-------
       Chapter 2—Assessment of Ultraviolet Light Effipacy, Viability, and Operational Factors
  Sobsey (1989) summarized data on inactivation of pathogens in water and wastewater by ultraviolet light.
  He noticed that vegetative bacteria (i.e., bacteria that propagate by nonsexual processes, such as coliforms)
  are inactivated (>3 log reduction) at doses below the DHEW-recommended minimum level  of 16
  mWs/cm2 and that higher doses are required to achieve 3 log reductions in viruses, bacterial spores, and
  protozoan cysts.  Data show that all bacteria and viruses (including Simian rotavirus SA-11), with the
  exception of Reovirus 1, suffered 3 log reduction at doses below the ANSI/NSF-recommended level of
  38 mWs/cm2, regardless of the liquid medium except for sewage medium.  Data compiled by Sobsey
  (1989) are presented in Exhibit 2-8.

  As, can be seen from Exhibit 2-8, bacterial sensitivity to ultraviolet light .varies from one species to
  another.  Even  the same species exhibit nonuniform sensitivity. This variation is a function of medium
  quality, source  of microorganism, age of the microorganisms, microorganism population, and possible
  measurement errors or inconsistent methods in measuring the applied average ultraviolet light dose.  The
,  range of ultraviolet light doses to disinfect bacteria (3 to 4 ^reduction) in media other than sewage is
  0.14 for Escherichia coli to 60 mWs/cm2 for B. subtilis spores.

 The, range of sensitivity within tested viruses as reported in Exhibit 2-8 is 21 to 45 mWs/cm2 at 3 log
 reduction. Also, the data presented above show that ultraviolet light is effective against protozoa at high
 doses.  The 3 log removal of a protozoa (Acanthamoeba Castellanii)  reported in Exhibit 2-8 at a dose
 of 100 mWs/cm2  and  that of a  1 log removal of another protozoa (paramecium) at the same dose as
 reported by Meulemans, 1987,  show that inactivation  rates for some groups of microorganisms  vary
 considerably.

 Sobotka (1993) concluded that  a bactericidal dose of  25 mWs/cm2 is  sufficient for most pathogenic
 organisms; however, Sobotka (1993) did not provide any specific evidence or cites for his conclusion.

Sommer and Cabaj (1993), using three different cultural techniques of Bacillus subtilis spores, concluded
that one of the three methods gave consistent inactivation rates between  a dose of 200 j/m2 to 900 j/m2
(20  mWs/cm2 to 90 mWs/cm2)  with 5.5  log reduction at 90 mWs/cm2 and 6  log reduction at 120
mWs/cm2.  In their experiment, Bacillus subtilis spores  were suspended in potable water and irradiated
in a commercially available drinking water ultraviolet disinfection unit.  The results of inactivation  of
Bacillus subtilis  spores depending on cultural methods are presented in Exhibit 2-9.  Sommer and Cabaj
(1993) recommended the use of cultural method C because it yielded Bacillus subtilis spores that were
UV Light Disinfection Technology in
Drinking Water Application—An Overview    2-11                       Final—September 1990

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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
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t/V L/gftf Disinfection Technology in
Drinking Water Application—An Overview
2-12
Final—September 1996

-------
       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

      Exhibit 2-9. Inactivation of B. subtilis Spores Depending on Laboratory Cultural
     	  -•  ;          ~  Methods (Sommer and Cabaj, 1993)
        0


       -1


       -2


       -3


      -4


      -5


      -6


      -7
          Reduction [log]
                                  •   MethodA

                                  +   Method B

                                  *   Method C
         0
20         40        60        80
          Dose (mWs/cm2)
                                                            100
120
                                                                         022E-12
    Bacillus subtilis (ATCC 6633) spores were cultured with three different methods.

    Method A:  Bacteria were inoculated on Cplumbia agar plates (Oxoid) with 2% CaCL, incubated
    at 37°C for 7 days, harvested, and suspended in sterile aqua dest.

    Method B:  Bacteria were inoculated on Schaeffer sporulation agar plates (Munaka and Rupert
    1972), incubated at 37°C for 6 days, harvested, and suspended in sterile aqua dest.

    Method C:  Schaeffer medium was modified as a liquid enrichment bouillon   'Bacteria were
    inoculated, incubated at 37°C for 3 days, harvested by centrifugation (4,000 g, 15 min  10°C) and
    suspended in sterile aqua dest.                                                  -
UV Light Disinfection Technology in
Drinking Water Application—An Overview
                      2-13
                                                                Final—September 1996

-------
      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 more resistant to ultraviolet light  treatment and showed a  linear relationship between dose and log
 reduction over a wider dose range than Methods A and B.' Sommer and Cabaj's study is discussed further
 under section 2.4.4.

 Wilson et al. 1993 tested the sensitivity of pathogenic water borne microorganisms to ultraviolet light.
 The researches conducted experiments on nine different water borne bacteria (Klebsiella Terrigena, vibrio
 cholerae, Salmonella  typhi,  Escherichia coli 0157:H7,  Shigella dysenteriae,  Yersinia enterocolitica,
 Campylobacter jejuni, Aeromonas hydrophila, and Legionella pneumophild) and three  different water
 borne viruses (rotavirus SA-11, pqliovirus type 1 and hepatitis A virus) in addition to coliphage MS-2.
 The researches used collimated ultraviolet light test apparatus, laboratory-cultured microorganisms and
 phosphate-buffered distilled water. The individual microorganisms suspension was placed in a petri dish
 and exposed to collimated ultraviolet light beam.  The test results of Wilson et al.  1993 are presented in
 Exhibit 2-10 and Exhibit 2-11. Exhibit 2-10 shows that under similar conditions, all tested pathogenic
 bacteria will suffer a minimum of 5  log reduction at an ultraviolet dose of approximately 16 mWs/cm2.
 Exhibit 2-11 shows that under similar conditions, all tested pathogenic viruses will suffer a minimum of
 6 log reduction at a dose of  about -60 mWs/cm2.  It is important to  note that naturally occurring
 microorganisms are typically more resistant to disinfection than laboratory-cultured microorganisms.  In
 addition the phosphate-buffered distilled water may  have lower ultraviolet demand than fresh water.

 Wilson et al. 1993 using the coliphage MS-2 inactivation data conducted  a linear regression analysis to •
 estimate ultraviolet dose with 95 percent confidence intervals.

 Wilson et al. 1993 reported ultraviolet dose predictions are presented in Exhibit 2-12.

 Considering the lower end of the 95 percent confidence interval and based on Wilson et al. 1993 work .
 (see exhibits 2-10 and 2-11), an ultraviolet light dose of 60  mWs/cm2 will result in more than  4 log
 reduction for the viruses tested  and more than 6 log reduction in  all the tested pathogenic bacteria.

 The results and statistical inferences of Wilson et  al., 1993  are supported by a more  recent research.
 sponsored  by the American  Water Works Association  Research "Foundation (AWWARF). In  their
 AWWARF- supported research, Snicer  et ai., 1996, concluded that 4-log inactivation of MS-2 can be
 achieved by an ultraviolet light dose of 64 mWs/cm2 to 93 mWs/cm2. Snicer et. al., 1996 also concluded
that 4 log inactivation of rotavirus, poliovirus and Hepatitis A virus can be achieved by an ultraviolet light
UV Light Disinfection Technology in
Drinking Water Application—An Overview     2-14                       Final—September 1996

-------
       Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
Exhibit 2-10. Survival Curves of Ultraviolet Irradiated'Bacteria 
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\\


D Klebsiellaterrigena
•*• Aeromonas hydrophila
A Yersinia enterocolitica




0 4 8 12 16 2

^\ : • '• " ' .
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n Salmonella typhi
+ Campylobacterjejuni
A Vibrio cholerae
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UV Dose (rriW sec/cm2)
l.^J' te j*s ^ere done in phosphate-buffered distilled water usinq laboratory
cultured microorganisms. **w*r+M+*g t f ^\*lMl t\JM\J^y Hi
Drinking Water Application—An Overview    2-15
                                                                    Final—September 1996

-------
      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
     Exhibit 2-11.  Survival Curves of Ultraviolet Irradiated Viruses and Test Surrogate
                            Coliphage MS-2 (Wilson et al., 1993)
1 ' • N
0.
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1 1 IX 1^1 1 • 1
0 20 40 60 80 100 120 140
UV Dose (mW sec/cm2)
* All tests were done in phosphate-buffered distilled water using laboratory
cultured micro-organisms. '
. _.
n Coliphage MS-2
+ Rotavirus SA-11
A Poliovirus type 1
• Hepatitis A

  Exhibit 2-12.  Ultraviolet Estimation From Linear Regression Model of Coliphage MS-2
                                    (Wilson et al., 1993)
Ultraviolet Dose mWs/cm2
38
46.5
60
120
Relative Standard Deviation
. 21%
17.3%
13.4%
6.74%
95% Confidence interval mWs/cm2
29.9-46.1
38.5-54.6
51.9-68.1
112-128
 'one tailed t test.                                                                        .
 dose of 50 mWs/cm2, 23 mWs/cm2 to 29 mWs/cm2, and 6 mWs/cm2 to 15 mWs/cm2 respectively. Snicer
 et al., 1996, conducted pilot scale and bench scale studies and pipe loop studies on waters from different
 groundwater sources. The two pilot plants constructed for the experiments operated for one full year. One
 pilot plant simulated  intermittent water use while the other operated continuously.  The bench scale
• laboratory studies were designed to compare MS-2 sensitivity to ultraviolet light to that of poliovirus,
 rotavirus and Hepatitis A virus (HAV). The bench scale laboratory studies also were designed to compare
 UV Light Disinfection Technology in
 Drinking Water Application—An Overview
2-16
Final—September 1996

-------
         Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
    the effects of varying groundwater quality on ultraviolet light dose requirements to achieve a 4-log
    reduction in the tested microorganisms.

    The pilot scale studies demonstrated mat 4-log reduction in MS^2 can be achieved through ultraviolet light
    disinfection. An ultraviolet light dose of 87.4 mWs/cm2 was sufficient to achieve 4 log reduction in ground
    water containing up to 0.65 ppm iron (the USEPA has set the secondary MCL of iron at 0.3 ppm). It was
    also found that performance and maintenance is a function  of water quality especially when water
    chemistry lends itself to deposition or scaling.  In addition, pilot studies found that electronic ultraviolet
    light sensors should be calibrated at the time of installation to guarantee reliable, and accurate results.

   Pipe loop studies showed that the use of Assimilable Organic Carbon (AOC) as an indicator was not
   sensitive enough to detect differences in regrowth potential in low TOC groundwaters, and that ultraviolet
   light did not significantly increase or decrease regrowth. Snicer et al., (1996), did not infer any detailed
   conclusions from  the loop  study  because of the cursory nature of the study. Laboratory  studies
   demonstrated that groundwater quality is  directly related to required  ultraviolet light  dose for viral
   inactivation. Ultraviolet light doses ranging from 64 to 93  mWs/cm* are required for 4-log inactivation
   of MS-2 bacteriophage in the groundwaters studied.

   Ultraviolet light disinfection systems operating  cost estimates ranged between $0.059 and $0.106  per
   thousand gallons assuming an ultraviolet light dose of 60 mWs/cm2 and a power cost of $0.15/kWhr and
   excluding maintenance and lamp replacement costs (Snicer, et al., 1996).

   Karanis et al. (1992)  examined the sensitivity of different protozoan parasites and bacteria to ultraviolet  •
   light.  Karanis et al. (1992) research shows that  ultraviolet light can kill protozoan parasites, cysts, and
   trophozbites, but these organisms require  a  higher dose than that needed to kin the less complex and
   smaller bacteria.  The results of Karanis  et al. (1992) experiments are presented in Exhibit 2-13.  As can
  be'seen  from Exhibit 2-13, commercially available  ultraviolet light  systems are effective  against
  Escherichia coli bacteria, with 3 log reduction at 152 mWs/cm2, but less effective against bacterial spores
  with 3 log reduction of B. subtilis spores at 50,mWs/cm2.

  Abbaszadegan et al. (1993) conducted experiments on POU systems that combined a carbon block filter
  with an ultraviolet light system.  The carbon block filter was designed to remove Giardia  lamblia cysts
-. and CryptQsporidium oocysts.  The ultraviolet light dose, as reported in the published study, was greater
  UV Light Disinfection Technology in
  Drinking Water Application-An Overview    2-17                        Final-September 1996

-------
      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
   Exhibit 2-13.  Comparison of Protozoan and Bacterial Sensitivity to Ultraviolet Light
                                     (Karanis et al., 1992)
Microorganism
Reduction (log AMV0)
Dose (mWs/cm2)
Medium
Parasites
Trichomonas vaginalis
secondary
culture
secondary
culture
Acanthamoeba /ysocfes3
cysts
trophozo'rtes
Acanthamoeba quina/lugdunensi&
cysts
trophozoftes
Giardta lamblia
human cysts
gerfail cysts
N
<3
NG"
>2.3
NG

1.8
1.6

<2
2-7

2
2

402
160-240
241
80

72
60

72
72

180
180

0.9% NaCI,

water from medicinal spring


dist. H2O
tap water

dist. H2O
tap water

dist. H2O
dist. H2O
Bacteria .
Escherichia coli (ATCC 1 1229)
Salmonella typhimurium
(ATCC 13311)
Yerslnla enterocolftica
(ATCC 2371 5)
B. subtilis spores (ATCC 6051)
3
<3
3
3
15
10
10
50
buffered water
buffered water
buffered water
buffered water
 ^Acanthamoeba cysts and trophozoites were 7 days old.
 "NG = No growth.
than 128 mWs/cm2. Abbaszadegan et al. (1993) reported approximately 4 log reduction in HAV, Giardia
lamblia, and Cryptosporidium parvum.  Other inactivation rates reported in the study of Abbaszadegan
et al. (1993) are presented in Exhibit 2-14.

It must be noted that the reductions in microorganisms presented in Exhibit 2-14 are the function of the
combined carbon block filter and ultraviolet light system. The published study did not provide any details
on the reductions achieved by the carbon block alone and those achieved by ultraviolet light. However,
the study shows a consistent pattern of sensitivity to ultraviolet light, with cysts being more resistant to
inactivation by ultraviolet light than viruses and viruses being more resistant than bacteria.
UV Light Disinfection Technology in
Drinking Water Application—An Overview
2-18
Final—September 1996

-------
       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  Exhibit 2-14. Average Log Reduction of  Microorganisms Using Combined Carbon Block
     Filter with Ultraviolet Disinfection Unit (>128 mWs/cm2) (Abbaszadegan et ah, 1993)
                    Microorganisms
                      Log Reduction
   Poliovirus
                                                                          4.28
   Rotavirus
                                                                          4.29
   HAV
                                                                          3.92
   MS-2
   Giardia lamblia cysts
                                                                          3.99
   Cryptosporidium parvum
                                                                          4.3
   Vibrio cholerae
                                                                          5.96
   Shigella dysenteriae
                                                                          6.7
   Escherichia coll
                                                                          6.3
   Salmonella typhi
                                                                         6.52
 ANSWSF Standard 55-1991 for POU Class A systems, which requires a minimum 38 mWs/cm2 dose to
 disinfect clear drinking water, was based on the work of Chang (1985) and Harris (1986). Chang's work
 (1985) as cited in-ANSI/NSF (1991) shows 3, to 4 log reduction in both poliovirus and rotavirus and a
 projected 6 log reduction of Escherichia coli at an ultraviolet light dose of 30 mWs/cm2.

 Harris' work (1986) as cited in ANSI7NSF  (1991) shows a 5 log reduction of poliovirus at a dose of
 40mWs/cm2.   NSF concluded that a 4  log .reduction  of poliovirus will be  achieved at a dose of
 38mWs/cm2.                                             .
                            :           '             .                     ,        -'A
                                           .-='.-                   - ' /-
 Exhibits  2-2 through 2-14 and the  above discussion illustrate that inactivation rates  of specific
 microorganisms vary among investigators. It is hypothesized that the previously cited characteristics of
 microbes tested and/or test conditions contribute to such differences.  Generally  speaking, however, the
 data show  clearly and with few exceptions  that  algae, fungi, protozoa, and bacterial spores are more
 resistant (in that order) to ultraviolet light than bacteria and viruses.  Also, gram-positive bacteria are more
 resistant to ultraviolet light than, gram-negative bacteria. Generally, gram-positive bacteria have thicker
 walls than  gram-negative bacteria; therefore,  they provide the cell's DNA with better protection from
ultraviolet light exposure (Ellis, 1991).
UV Light Disinfection Technology in
Drinking Water Application—An Overview
2-19
Final—September 1996

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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 2.2.3  Cryptosporidium parvum Oocysts and Giardia muris Cysts Inactivation Rates
        Using Ultraviolet Light
 Under normal conditions, ground water sources are not expected to contain Cryptosporidium species or
 Giardia species. However, primary sources of ground water contamination are leaks from septic tanks,
 cesspools, drainage fields, municipal sewer systems, and treatment lagoons (Wolfe, 1990).  Also, in cases
 of floods, natural disasters, or failure of a well casing, ground water might come under direct influence  '
 of Cryptosporidium- and Giardia-containing surface water.

 This section and the following section are intended to provide available information about ultraviolet light
 doses needed to disinfect water that deteriorated in quality and that might contain pathogenic protozoa.
 Operators in such emergency situations have been known to  increase ultraviolet dose by increasing the
 electric potential difference (voltage) and/or by reducing the flow rate to increase the residence time as
 deemed necessary.

 In 1985, the USEPA (Carlson et al., 1985) funded a project to study the use of ultraviolet light to disinfect
 drinking  water for  small  water supply  systems. Giardia muris cysts, Yerisinia enterocolitica,  and
 EscJierichia coli were spiked into an ultraviolet light treatment unit influent.  The researchers found that
 Giardia nutris cysts .are more resistant "to ultraviolet light than  Yerisinia enterocolitica and Escherichia
 coli.  The researchers also'found that the presence of relatively small inorganic or organic particulates (5
 pm diameter or less) had no discernible effect on the ultraviolet light disinfection of cysts. In contrast,
 turbidity in the form of particulates (> 5 um) may provide shielding and protection to the organisms
 present in the treated water.  To achieve less than 1 percent  survival rate  of Giardia muris cysts, a
 minimum ultraviolet light dose of above  121 mWs/cm2 is needed (reported  intensity 0.0914 mW/cm2,
 exposure time 22 minutes).  Exhibit 2-15 is  a graphical presentation of Giardia muris cyst survival rates
 as reported by Carlson et al. (1985).

 Karanis et al. (1992) examined the disinfection capabilities of ultraviolet light against protozoan parasites.
The researchers used Giardia lamblia cysts extracted from both animals and humans. Both groups of
cysts suffered a 2 log reduction when irradiated by ultraviolet light at 180 mWs/cm2 dose (see Exhibits
2-13 and  2-16).  Karanis et al. (1992) also used lab-cultured  protozoa and  protozoa in dormant and
vegetative states  from human and animal sources along with  different types of bacteria to test then-
sensitivity to ultraviolet light (most of the experiments were conducted using distilled or buffered water).
UV Light Disinfection Technology in
Drinking Water Application—An Overview    2-20                       Final—September 1'996

-------
       Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
     Exhibit 2-15. Giardia muris Cyst Survival Percent Versus Ultraviolet Light Exposure
                   :                      (Carlson, 1985)
                                              Ptin Ray UV Bench-Scale Study
                                              1-Liter. 4-inch Diameter Vessel
                                                    2nd Fttm (9/27/83)
                                                    3rd Run (10/4/831
                                             m this experiment was 0.0914 mW/cm<
                                                                              35
           20        25        30
   Exposure Time, min
82.3      109.7     137.1     754.5    791.9
UV Dosegc. i
 Exhibit 2-16 clearly shows that the source of parasites is important in determining dose requirements and
'tfaatlhe growth stage of the microorganism is another important factor. As can be seen from Exhibit 2-16,
 Aconthamoeba rhysodes trophozoites are more sensitive to ultraviolet light than Acanthamoeba cysts at
 a dose of about 38 mWs/cm2 but more resistant to inactivation at a dose above 40 mWs/cm2.

 Campbell et al. (1995) used a low-pressure ultraviolet light system of a theoretical minimum intensity of
 14.58 mWs/cm2 at the germicidal wavelength of 253.7 nm for  10  minutes (ultraviolet  dose  8,748
 mWs/cm2) for the purpose of inactivating Cryptosporidium parvum opcysts. The preliminary results from
 Campbell et al. (1995) show a potential for inactivating Cryptosporidium parvum oocysts in clean water,
using an ultraviolet light disinfection system.  CampbeU et al. (1995) indicated that the  2 to  3  log
reduction in the viability of oocysts of Cryptosporidium parvum is a conservative estimate of the .actual
inactivation because the viable oocysts count is restricted by the limitations of the standard enumeration
technique developed by Campbell et al. (1992) (vital dye assays that rely on morphology and inclusion/
UV Light Disinfection Technology in
Drinking Water Application—An Overview
       2-21
                                                                      Final—September 1996

-------
      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
        Exhibit 2-16. Ultraviolet Irradiation Curves for Protozoan Type Organisms
                                     (Karanis et a!., 1992)
                                                    (a)
                                 50
                                        100
                                               150
                                                      200
                                 Dose mWs/cm2
        Ultraviolet irradiation curves (a) 48-h-o!d Trichomonas vaginalisirom a medicinal spring (5 x 104
        trichomonads/ml; n=10 trials), (b) Acanthamoeba rhysodesirom tap water (1x103amoebas/ml:)
        (o) 7 day-old-trophozoites (n=2 trials). (•) 28-day-old cysts (n=3 trails), (c) Giardia lamblia from
        distilled water: (a) 2 x 1034-9-day-oId group: cysts/ml from humans (1 trail);  (•) 9-27 x 10s 3-9-
        day-old group II cysts/ml from gerbils (n=4 trials).        .   .
UV Light Disinfection Technology in
Drinking Water Application—An Overview
2-22
Final—September 1996

-------
       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  exclusion of two vital dyes).  To adequately determine ultraviolet light disinfection potential against
  Cryptosporidium parvum using the same system and dose, Campbell et al. (1995) recommended the use
  of an automated counting system such as flow cystometer and suggested that the use of such technique
  might reveal an actual log reduction in viability that is higher than the morphological enumeration
  technique used by the researchers. The best defense against Cryptosporidium parvum is filtration, with
  slow sand filtration providing the possibility of 5 to 6 log reduction in oocysts (Jeffrey, 1991).

  A recent report (SWS, 1996)  by Clancy Environmental Consultants  (CEC), with the  support of the
  University of Arizona,  agrees generally with the above-cited findings  of Campbell et al. regarding the
  efficacy of ultraviolet irradiation of Cryptosporidium parvum in water.  The device, composed of filters
  (2 urn nominal) that capture  Giardia  and Cryptosporidium oocysts  and ultraviolet irradiation  at  a
  maximum dosage of greater than 8,000 mWs/cm2, was tested and found to produce a greater than 3 log
  reduction in  oocyst viability. Tests were conducted on cold (4°C) treated surface water. In addition, an
 accompanying animal infectivity study was conducted that led investigators to believe that reductions may
 have been much greater, because no animals were found to be infected. Some cautions were expressed
 by the investigators, mainly in the area of examination  of oocysts microscopically for physical
 characteristics, damage, and/or viability.  Evidently the animal infectivity part of this study provided
 greater confidence in the cyst-reduction  results. The investigators also point to  the need for additional
 study of the  ultraviolet treatment unit used in the experiment under differing water quality, including
 ground waters and finished surface waters. Mineral content, natural organics, and inorganic debris (silica,
 clay) could affect treatment (SWS, 1996).

 Recent research studies conducted by Bank et al.  (1990) and Dunn, Ott, and Clark (1995) on the use of
 new ultraviolet light manipulation-techniques to  inactivate  Cryptosporidium parvum are discussed in
 Appendix B of this report.

 2.2.4   Doses and Inactivation Rates Achieved in Wastewater Treatment as Compiled
        from the Scientific Literature             (
 The National  Water Research Institute (NWRI, 1993) proposed guidelines for wastewater reclamation in
 California that call for a minimum dose of 140 mWs/cm2 to disinfect filtered, secondary effluent. This
dose is  based on pilot studies in which  4  logs of inactivation of polioviras  were accomplished at an
ultraviolet dose between 100 and 120 mWs/cm2. The works of Chen and Kuo (1992) and CH2M HILL
(1992) were,cited as a_base for the above recommendation  (NWRI, 1993).
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 In a Canadian pilot plant study, Zukovs et al. (1986) applied ultraviolet light to disinfect effluent combined
 sewer overflows (CSOs).  Log reductions ranging from 1.5 to 3.5 for Pseudomonas aeruginosa were
 achieved at ultraviolet light doses of 100 mWs/cm2 to 500 mWs/cm2. Pseudomonas aeruginosa can cause
 illness, especially in immunodepressed patients. In water jt can be found even in the absence of coliform
 bacteria and can cause enteric, eye, ear, and upper respiratory tract infections (USEPA, 1984);

 Dizer et al. (1993) conducted a detailed study on the use of ultraviolet light for inactivation of bacteria
 and coliphage in a mix of 70 percent domestic wastewater secondary effluent and 30 percent  surface
 water. Dizer et al. (1993) also used cultured bacteria that were artificially added to the ultraviolet reactor.
 The results of his study are presented in Exhibit 2-17.  The reduction in inactivation rates in coliphage
 adsorbed to colloidal material from 94 percent (1.22 log reduction)  to 54 percent (0.34 log reduction)
 indicates the limits of ultraviolet use for disinfection of turbid or unfiltered drinking water sources at the
 dose used in this experiment.
   Exhibit 2-17.  Inactivation of Microorganisms in a Mix of 70% Domestic Wastewater,
      Secondary Effluent, and 30% Surface Water as Reported in Dizer et al. (1993)
Microorganism
Range of Log Inactivation9
11 2
3
-4
Natural " •
Total Coliform
E. Col!
Fecal streptococci
Colfphage f2
<***********>
<*""**"**>
1









Artificial Trter
Coliphage f2
Adsorbed Coliphage f2b
Free Coliphage 12°
Salmonella enteritidis
Streptococcus faecalis ,
<***********>
0.33
1.22
I









*

'Reported ultraviolet light dose in the study is 47 mWs/cm2. Residence time 3.54 seconds.
Introduced to the reactor adsorbed to colloids in a slurry containing fine sand soil sediment of 0.1 g/ml concentration.
introduced to the reactor in a slurry medium containing fine sand soil sediment of concentration of 0.1 g/ml.

Dizer .et al. (1993) results show lower inactivation rates when compared to experiments using laboratory-,
cultured microorganisms.  Reports of the high sensitivity of various laboratory-cultured microorganisms
to ultraviolet disinfection as compared with naturally occurring microorganisms confirm the findings of
Dizer et al. (1993)  (Martiny, Wlodavezzyk, and Riiden 1988; Martiny et al., 1988; Martiny, Seidel, and
Riiden, 1989; and Sommer et al., 1989).                              '..'•-.
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  Naranjo et al. (1993) evaluated the removal of coliphage MS-2, rotavirus SA-11, and poliovirus 1 from
  wastewater by ultrafiltration and ultraviolet disinfection. The study did not report the intensity, time, or
  dose of ultraviolet light applied. The study reported an average removal of MS-2 of more than 4 log in
  all tests after ultrafiltration achieved log reduction between 2.3 and 3 in four experiments.  Because of the
  high levels of viruses used in the study, Naranjo et al.  (1993) concluded that using this system to treat
  drinking water would result in no detectable enteric viruses in the final product water.

  In recent research, Oppenheimer et al. (1993)  conducted a study on microbial inactivation rates and by-
  products formation in reclaimed water in California. Oppenheimer et al. analyzed samples collected from
  tertiary effluent at the Elsinore Valley Municipal Water District (EVMWD) Regional Plant.   The
 bacteriological analysis included heterotrophic plate count, fecal streptococci, fecal coliform, total coliform,
 OX174 virus, MS-2 bacteriophage, and enterococci. The inactivation rates test results of Oppenheimer
 et al. are presented in Exhibit 2-18.  The tertiary effluent quality parameters include a total dissolved
 solids level of 664 mg/L, a turbidity level of 0.6 NTU, a nitrate level of 13  mg/L as N, and a TOC level
 of 5.6 mg/L.   Exhibit  2-18 shows that the bacteriophage MS-2 is more  resistant to ultraviolet light
 treatment than all the other microorganisms tested in the experiment.

     Exhibit  2-18. .Ultraviolet Light and Chlorine Doses to Achieve 99.9% Inactivation
             of Microorganisms in Reclaimed Water (Oppenheimer et al., 1993)
Organisms
Ultraviolet Light Dose (mWs/cm^)
Chlorine Dose* (mg/IY
Bacteria
Heterotrophic Plat Count •
Total Coliform
Fecal Coliform
Fecal Streptococci
Enterococci
70
35
30 '
30
30
3.0
2.5
1.5
.2.5
3.0
Virus
MS-2 ,
«>X174
85
20 ,
1.0
0.5
*2 hours contact time.
Ultraviolet light treatment pilot studies have been plagued by varying sensitivity of bacteria and the
differences in applied intensities or the lack of reporting for such information. Quails et al. (1985), using
a simplified system where various water quality parameters could be accurately measured, conducted an
average of 33 to 35 observations of irradiated unfiltered effluent samples and concluded that ultraviolet
light sensitivity of a single cell and small aggregates of coliforms are relatively uniform from plant to

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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 plant.  However, the wide variation in survival curves is caused by the varying degree of protection
 afforded by different particle sizes  arid by the varying proportion of coliforms that are aggregates or
 attached to colloids particles. Exhibit 2-19, provided by Quails et al. (1985), is useful as a generalized
 range of coliforms survival data for planning equipment needs where accurate dose-survival data do not
 exist and pilot studies are deemed expensive.  The upper and lower graph boundaries represent samples
 ± standard deviation bars.                                             '                .
   Exhibit 2-19.  Average 33 to 35 Observations of Log Survival of Co I if or m Bacteria in
                     .  Unfiltered Effluent Samples (Quails et al., 1985)
                  Or-
                                10
15    20     25    30
DOSE (mW-s/cm2!.
                                                                35
                                                                       4O
     45
Harris et al. (1987) studied the effects of turbidity on ultraviolet disinfection of secondary municipal
wastewater effluents and photoreactiyation potentials using two different ultraviolet light reactors.  Harris
et al. observed up to 2 log survival in total coliform photpreactivation and little evidence of photo-
reactivation of fecal streptococci. Exhibit 2-20 is  a graphical presentation of the relationship between
ultraviolet absorbance at 254 nm and turbidity as reported by Harris et al. 1987. The study showed highly
significant correlations between suspended solids, fecal coliforms survival at 5 mWs/cm2, and ultraviolet
light absorbance at 254 nm. The researchers concluded that wastewater turbidity can be used as a good
surrogate measure of disinfection efficiency and ultraviolet light absorbance. The graph shows that at a
turbidity level close to 5 NTU, about 25 percent of ultraviolet light transmittance is absorbed by turbidity-
causing wastewater constituents. It should be recognized that other factors (iron, organics, etc.) may play
an additional role in absorbing  ultraviolet light in practical drinking water use.   However, for drinking
water applications and in the absence of similar experiments in turbid drinking water, the Harris  et al.
work can be used as a base to account for turbidity absorbance of ultraviolet light.
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        Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  Exhibit 2-20.  Ultraviolet Light Absorbance as a Function of Turbidity (Harris et al., 1987)
         W.O
          4.0-
         2.O-
         0.0
                  Turbidity - 28.18 Absbrbonce  -2.26
                  r'-O.TS
                                 0.70        0.25        0.30
                                        UV Absofbonce (254 nm)
                                0.40
                                           0.48
 2.3    ULTRAVIOLET LIGHT OPERATIONAL FACTORS
 In this section, factors  such  as  operating procedures and requirements, maintenance  requirements,
 installation features, and  design elements are analyzed to determine the viability of ultraviolet light in a
 ground water treatment setting.-This section is organized as follows:  section 2.3.1 presents a general
 description of  ultraviolet light equipment operational factors; section 2.3.2 discusses water .quality
 considerations.  Hydraulic design considerations are presented in section 2.3.3; and design considerations
 specific to small systems are presented in section 2.3.4.

 2.3.1   Equipment Operational Factors
 Ultraviolet light bulb efficiencies decline over time. Therefore, it is important when adopting a standard
 for ultraviolet light treatment that the standard reflect the efficiency  of the light bulb at its lowest point
 according to the manufacturer's suggested effective use time. The current effective life of ultraviolet light
 bulbs ranges from 7,000 to  14,000 hours (Aquafine, 1995).  Industry brochures show about 30 percent
 reduction in light transmission efficiency over aperiod of 10,000 hours. Operators and maintenance crews
need to be adequately trained to service the equipment as recommended by the manufacturer.
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
The operational factors that affect adequate performance of an ultraviolet light system are lamp output,
lamp aging, and fouling of unit surfaces.                 '

2.3.1.1   Lamp Output
Ultraviolet lamp output is directly dependent on the optimum conditions of the mercury vapor discharge
requirements.  These requirements include a steady  electric potential that does  not fluctuate and drop
below a certain level set  by the designer.  For example, a drop of 5 volts ,in the electric potential
difference acting on a 5-amp lamp means a drop of 25 watts in energy available to the  lamp.

Another factor that affects the output of a standard ultraviolet lamp  is temperature.  The optimum
temperature for maximum ultraviolet lamp efficiency is generally between 35°C (95°F) and 50°C (122°F).
Maintaining optimum temperature and pressure in an ultraviolet lamp is important to maintain maximum
light emission at the desired wavelength.  This concern is less important in new ultraviolet lamp  models
that have devices to regulate temperatures and in those that can operate at temperatures higher than 50°C
(122°F).

2.3.1.2   Lamp Aging
Several factors affect the performance of an ultraviolet lamp as it advances in hours of use:  solarization
(i.e., the effect of ultraviolet light on the lamp and the sleeve that causes lamps to become opaque over.
time), electrodes failure, and plating of the mercury to the interior lamp wall.  If combined, these factors
might reduce the efficiency of an ultraviolet light lamp by as much as 30 percent after 7,000 hours of use.
The electrodes in an ultraviolet lamp will deteriorate progressively with an increase hi the number of times
the lamp is started.  According to various industry sources, the maximum allowed number of starts per
lamp per day is four. In a typical potable water application, ultraviolet lamps are expected to run 24 hours
per day. According to various industry sources, the current effective life span  of an ultraviolet lamp
ranges from a minimum of 7,000 hours to,a maximum of 14,000 hours.             •

2.3.1.3   Fouling and Plating of Lamps and Sleeves
Fouling of the  unit's  quartz sleeves surface reduces the light energy  reaching the volume of water.
Typically, high quality fused quartz sleeves have a transmissibility of more than 90 percent when new and
clean.  With time, the surfaces of  the quartz sleeves that are in contact with the body of water start
collecting organic and inorganic debrisr—such as calcium scale, silt,  or iron fouling—causing a reduction
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        Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  in transmissibility.  Therefore, it is very important to maintain the surfaces of the sleeves to ensure that
  they are clean and free of deposits.                                              .      -

  To .maintain clean ultraviolet units, mechanical wipers can be used.  However, like all other mechanical
  devices, they must.be checked periodically to ensure that they are sufficiently cleaning the lamps. To
  combat fouling, ultrasonics are highly recommended in hard water situations and in .ground water that
  contains iron.  The alternative to ultrasonics is the periodic use of detergents such  as sulfuric acid or
  hydrochloric acid.  To combat plating (forming a thin coating on surfaces), high water pressure also is
  used effectively to routinely clean the inside surfaces of the ultraviolet unit. High water pressure cleaning
  techniques are recommended in situations where ground water contains very fine silt materials, sulfites,
  or manganese.                                            \                                  .

  Kreft, Scheible, and Venosa (1986), based on hydraulic studies conducted on three wastewater ultraviolet
  treatment  units, recommended both chemical and physical cleaning of ultraviolet units. They  also
  suggested the use of high-pressure nozzles to scour fouled surfaces and arecirculation system for chemical
 cleaning. The researchers found that.wipers and ultrasonics have a great potential for keeping clean units,
 but neither negates the necessity for occasional chemical treatment or swabbing of the ultraviolet tubes.-

 2.3.2  Water Quality Considerations
 The performance of an ultraviolet disinfection system is directly related to ultraviolet light absorbance by
 the  treated water.  When ultraviolet light travels through the water body, the light intensity decreases as
 the  distance from the light source increases. This is  caused by energy dilution as light dissipates in a
 larger volume  of water.  Another  factor  that causes  ultraviolet light to  be absorbed is'water quality.
 Ultraviolet absorbance by water is analogous to chlorine  demand  in  chemical  disinfection processes.
 However, with respect to ultraviolet applications, Weber (1989) suggested that pure water also exerts an
 ultraviolet demand.  Weber (1989) reported that even distilled water absorbs about 8 percent of the applied
 ultraviolet energy at a depth of 3 cm'.                                                        ,    '

 The transmittance of water commonly is used to describe the ultraviolet demand. This can be determined
 from the absorbance measurement expressed in percent:

                               %  Transmission = 100 x  l(T(a-u-A:m)-d
            .Where:                  a.u. = absorbance units
                                       d = distance in centimeter

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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 The percent absorbed is 100 percent minus transmission.  The parameter most often used for design
 purposes is the Coefficient of Absorbance (C of A) or cc expressed as
                                        a = 2.3 (a.u./cm).
 The unit of ultraviolet absorbance coefficient is cm"1.
 In general, ultraviolet absorbance coefficients decrease with an increase in water quality.

 Exhibit 2-21 (courtesy of Aquafine Corporation) presents absorbance coefficient curves as a function of
 ultraviolet light  transmission and  distance.   For  ground water systems using  ultraviolet light for
 disinfection, it is important to determine the absorbance coefficient by sampling at different periods during
 the year to  account for seasonal and temporal water quality fluctuations.  In the absence of field data,
 Exhibit 2-21 or similarly constructed graphs can be used to select an appropriate absorbance coefficient.
 From Exhibit 2-21, an absorbance coefficient of 0.1 may be a reasonable conservative assumption "a"
 value for ground water.
            Exhibit 2-21.  Ultraviolet Transmission and Absorbance Coefficient
                            (Source:  Aquafine Corporation, 1995)
                                    C of A Values
      o
      1
      i
    High purity water: a = 0.01
    Municipal drinking water:  a = 0.06 to
                              a = 0.15
    % Transmission at "d": = 100 x'lo;(ail-/en*d
                           = 100 x e^"
              0   2   4   S  8 18  12  14  16  11
                       Distance (cm)
As with other disinfection technologies, better disinfection results are achieved with ultraviolet light if the
water is free of turbidity.  Ultraviolet industry representatives recommend that ground water with a
turbidity level of 5 Nephelometric Turbidity Units (NTUs) or more should be treated for turbidity removal
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        Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  before it is ran through the ultraviolet light reactor (Atlantic Ultraviolet Corporation, 1995a; Voitle, 1994;
  Wagenett and Lemley,  1994). Similarly, ground water with suspended solids levels of more than 10 mg/L
  (10 mg/L was the U.S. Department of Health drinking water standard for turbidity [Steel, I960]) should
  be monitored to determine whether the high levels are of a permanent, seasonal, or ephemeral nature.
  Knowing the upper range of suspended solids in water is important in order to determine which type of
  ultraviolet light unit will be required.

  In wastewater applications, ultraviolet systems are designed to accommodate liquids with suspended solids
  levels as high as 30 mg/L for any consecutive 30:day period (WPCF,  1986).  Therefore, ultraviolet
  systems for ground water disinfection could be designed to allow for high suspended solids situations
  although such levels are not expected to occur in drinking water situations. To compensate for ultraviolet
  light absorbed by high levels of suspended solids, higher ultraviolet light doses need to be applied in order
  to achieve desired levels of disinfection.

  The two major water quality factors that affect the performance of an ultraviolet unit in (clear) ground
  water are microbial factors and chemical factors.

  Severin, Suidan, and Engelbrecht (1983) studied the-effects of temperature on ultraviolet light disinfection
  and found that ultraviolet disinfection is relatively insensitive to temperature changes.  The disinfection
 tests were conducted at 5°C, 20°C, and  35°C.  However,  earlier in vitro studies showed  that more
 disinfection may occur at lower temperatures than at higher temperatures because at lower temperatures
 (below 25°C), single-stranded polynucleotides and DNA strands are in a stacked configuration. Stacked
 DNA and stacked single-stranded polynucleotides are more subject to dimerization than unstacked DNA
 (Rahn, 1970).  Malley, Shaw and Ropp, 1996 (as cited  in Snicer et al., 1996) concluded that pH levels
 might have an effect on ultraviolet light disinfection efficiency. The researchers attributed the detected
 effect to morphological changes in the nature of the protein coat that caused clumping of microorganisms.
 Montgomery (1985) and USEPA (1986) reported that disinfection by ultraviolet light is pH independent.
 As mentioned earlier, AWWA (1992) reported that research studies conducted at the University of New
 Hampshire show that ultraviolet light disinfection processes  are independent of water pH.   Therefore,
 unlike chemical disinfection processes,  water quality parameters such as temperature and pH have an
 insignificant effect on ultraviolet light disinfection capabilities. In chemical "disinfection processes, an
-increase in temperature  results in an increase in the killing rate  of the  disinfectant.  This, could be
 explained in the context of increased chemical reaction rate and in the decrease of surface tension between
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 microorganisms, microorganisms and colloidal particles, and the decrease in the viscosity of the medium
 (Gaudy and Gaudy, 1980). In chemical disinfection processes, pH influence on disinfection rate varies
 from one chemical to the other. For example, an increase in pH will decrease the disinfection efficiency
 of chlorine gas and slightly increase the disinfection efficiency of chlorine dioxide (Montgomery, 1985).
                             *.                                  .•-.-•
 Important microbial water quality parameters to be taken into account when selecting an ultraviolet unit
 for disinfecting ground water are the microbial water quality and the densities of the microbial population.
 High densities of the microbial population may cause a decrease in the inactivation efficiency of ultraviolet
 light by shielding and  hosting. For an adequate evaluation of the microbial parameters and the potential
 for microbial contamination, it is recommended that water samples be taken during the warm season after
 a rainy period to test for Heterotrophic Plate Count (HPC), HPC, also known as the standard plate count,
 is a procedure for estimating the number of live heterotrophic bacteria in water and measuring changes
 during  water treatment and distribution.  In an HPC procedure, colonies may arise from pairs, chains,
 clusters, or single cells, all of which are included in the term "colony-forming units" (CPU).  A high HPC
 of more than 500/ml may cause a decrease in inactivation rate of viruses (by shielding and hosting).
 Therefore, it is important to have the microbial data available before purchasing and installing an
 ultraviolet unit.

 The effect of  the ultraviolet light on microorganisms is a  function of  the energy absorbed by the
 microorganism. The energy absorbed is defined as the product of the rate at which the energy is delivered
 and  the length of time the microorganism is exposed to that intensity.

 The ideal ultraviolet disinfection model follows Chick's law (Chick, 1908) whereby:
        N   =  Noe'*1                           ;     -  .
 Where  No =  initial bacterial population
        N   =  surviving  bacterial population after exposure to ultraviolet  light
        k   =  rate constant
        i    =  intensity of ultraviolet light
        t    =  time of exposure.

Exhibit 2-22 is a graphical presentation of Chick's law and deviations from it.  Chick's law assumes a
uniform susceptibility of all organisms within the strain  or species. Deviations from this ideal first order
representation are manifested by tailing effects and shouldering. In general, the presence of "shoulders"
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       Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
               Exhibit 2-22.  Chick's Law and Deviations (Source:  USEPA, 1986)
  o
Z
 O
^5
 CO
oc
1
•>
D
                          C?
                                                Shoulder
                                                (Threshold dose)
                                                              Tailing
                               Ideal First Order
                                        = e
                                     UV Dose {Dose = IT)
 indicates a time lag between the application of ultraviolet light and the onset of disinfection. The presence
 of "tailing" indicates a decrease in the rate of inactivating surviving microorganisms at higher ultraviolet
 energy doses.             ,

 The presence of a "shoulder" or "tailing off' or both may be explained by the following:

        • The presence of protective extracellular layers                 '
        • The  presence of colloids that absorb ultraviolet light
        • The  presence of organic and inorganic substances that absorb ultraviolet light
        • The presence of organic and inorganic substances that induce microbial resistance to ultraviolet
          light.                                                             ......           .

        • Inherent differences in sensitivities of the microbial population.

 Although avoiding "shouldering" and "tailing off' in disinfection processes is difficult, knowing water
 quality parameters and designing an ultraviolet system accordingly may result in a lesser manifestation
 of such phenomena.
Like chemical disinfectants, there are chemical and water quality factors that affect the performance of
an ultraviolet light disinfection unit. These factors are presented in Exhibit 2-23 and include hardness,
nitrites, sulfites, manganese, and aromatic organics levels. These water quality factors are known to,
                                                                                         icause
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
Exhibit 2-23. Factors Affecting Ultraviolet Light Disinfection Performance*
Factor
Hardness
Iron
Nitrites
Sulfites
Manganese
HPC
Aromatic organics
Turbidity
Ultraviolet transmission
inorganic suspended solids
Color
> 100 mg/I
£ 0.2 mg/I
> 500
> 10 NTU
< 75%
> 5 urn
> 15 NTU
Short circuiting in contact chamber
High flow rate
Low line voltage supply
Improper lamps arrangement
Effect
Plating**
Fouling***
Plating
Plating
Plating
Decrease inactivation of viruses
Plating
Plating
•Inadequate destruction
Shielding
Reduce disinfection efficiency
Inadequate inactivation
Reduce disinfection efficiency
Low light transmission
Low light efficiency decrease inactivation efficiency
'USEPA, 1992. Draft Ground Water Disinfection Rule FR.; Negron, 1994.
"Forming a thin coating on surfaces.
""Incrustation.
plating (the coverage of inner surfaces with a layer of minerals) and fouling (the formation of a crust on
sleeve and inner sides of the unit) in ultraviolet units that are not equipped with mechanical wipers and
ultrasonic cleaners. "Plating and fouling cause inadequate ultraviolet light transmittance and a decrease in
inactivation efficiency.  Modern ultraviolet units  are equipped with automatic wipers and ultrasonic
cleaners. The continuous action of the mechanical wipers along with periodic ultrasonic cleaning greatly
reduces plating and fouling. It is recommended, as a good process tracking tool, that a log be maintained
to record all water quality parameters to recognize any change in ground water quality.  For example,
levels of nitrites in particular are required to be kept at less than 1 mg/L. Nitrites are regulated under the
National Primary Drinking Water Regulations, and their presence in ground water sources may indicate,
in the absence of any other explanation, a fresh contamination  that requires immediate response.

Other secondary contaminants need to be removed for other reasons.  For example, although iron is not
a primary drinking water contaminant, iron removal from drinking water sources is highly desirable and
is more economical at the treatment plant than at the tap.  Ground  waters with dissolved iron content
above 0.3 ppm will cause brown-red stains on sinks, porcelain, and bathroom fixtures. Upon heating, the
clear water color will turn brown-red and will cause cloth discoloration and brown-red stains on cooking
pots. At above 3 ppm of iron content, the water will have an offensive metallic taste and the water will
be colored.  In some cases, precipitation will occur; in  other cases,  a brownish cast  that does not
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 precipitate will persist.  Some iron-containing waters have iron in colloidal form, thus making drinking
 water very offensive to look at and to use for drinking, cooking, or washing (USEPA, 1991a). Although
 there are no known health risks associated with high iron levels in drinking water, aesthetic qualities are
 very important to assure users of the safety .of their drinking water,

 2.3.3   Hydraulic Design Considerations
 The major elements that must be considered in the hydraulic design and operation of an ultraviolet reactor
 include the following:                          .

         •  Dispersion .   .
         •  Turbulence
         •  Effective volume           ,
         •  Residence Time Distribution (RTD)                      _ -
         •  Flow rate.

 2.3.3.1   Dispersion
 Dispersion is the characteristic of water elements to scatter spatially in two or three dimensions. The ideal
 ultraviolet light disinfection reactor is a Plug-Flow Reactor (PFR).  In a PER,, water particles are assumed
 to enter into the reactor and discharge from the reactor in the same sequence they entered.  Therefore, in
 a PFR, each element of the water passing through the reactor resides in the reactor for the same period
 of time. Hence, an ideal PFR has no flow dispersion. In reactor design, this type of flow is approximated
 in a long tank with high  length-to-width ratio in which longitudinal dispersion is absent or minimal.

 2.3.3.2   Turbulence
 In addition to the desired PFR characteristics, an ideal ultraviolet light reactor is a reactor with a flow that
 is turbulent radially from the direction of flow with  no dead zones. The radially turbulent flow pattern
 promotes more uniform application of ultraviolet light. However, having a radially turbulent flow results
 in  some axial dispersion, thus disrupting the ideal plug  flow sought in a disinfection reactor.  By not
 aligning inlets  and outlets of units and using perforated.baffle plates, designers  accommodate the
contradicting plug flow and turbulence requirements.

2.3.3.3   Effective Volume
Avoiding dead  zones (i.e., areas of no or reduced flow)  results in maximum use of the volume of the
reactor. It also results hi an effective, volume as close as possible to the actual volume Available. Exhibit

UV Light Disinfection Technology in                                                    ,
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 2-24 presents a configuration (top figure) of a closed ultraviolet light reactor where dead zones are induced
 by a specific, inlet and outlet configuration. Trie exhibit shows how the introduction of perforated baffle
 plates can help distribute the flow over the entire cross-sectional plane of the reactor, thereby eliminating
 dead zones.

               Exhibit 2-24. Closed Ultraviolet Light Reactor (USEPA, 1986)
Lamp Battery (Generally
parallel to flow Path)
                                                     \_
                                                   /, /
                                                         Potential
                                                         Dead Zones
                                   Perforated Baffles
2.3.3.4   Residence Time Distribution (RTD)
RTD is used as a design and diagnostic tool to determine the effects of hydraulics on the ultraviolet
system performance.  The shape of the curve and the distribution of the area under the curve indicate the
hydraulic characteristics of a system and also indicate whether it is close to an adequate disinfection
design.  Exhibit 2-25 presents RTD curves for various flow characteristics.

An RTD curve closer to a Continuous-Flow Stirred Tank Reactor (CSTR) or to an arbitrary flow curve
than to a PFR curve indicates inadequate performance and poor design.  An RTD curve is generated by
sampling water at  successive intervals of time to measure for  concentrations of a  non-reactive
(conservative) tracer that is pulse-injected into the reactor and then plotting the concentration values versus
time. Detailed discussions on RTD and dispersion models in plug-flow reactors are found in Metcalf and
Eddy, 1991; USEPA, 1986; and WERF, 1995.
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       Chapter 2—Assessment of Ultraviolet Light Efficapy, Viability, and Operational Factors
                       Exhibit 2-25.  Residence Time Distribution Curves
                                      Flow Characteristics
                                                                Arbitrary (c)
                                                                Row
                         (Age Distribution)
                                     Area =
      (a) CSTR
      (b)PFR
      (c) Arbitrary
      (d) Hypothetical Resj
                              Concentration
                                   o*
                                 Tracer
 2.3.3.5   Flow Rate
 The flow rate is usually set by design based on projections of water consumption.  Because multiple
 parallel ultraviolet units may be used in a water treatment plant, balanced flow split between modules is
 important for two reasons:  first, the balance will avoid overloading a single unit or group of units,
 hydraulically and with deposits, and second, the inactivation rate increases as flow rate decreases (Sommer
 and Cabaj, 1993).          -      .  ,                                              -
                 /         ,                  .                     "                i          '
 Sommer and Cabaj (1993) conducted experiments on Bacillus subtilis spores using various flow rates of
 potable water and ultraviolet doses.  The researchers showed that a decrease in ultraviolet transmission
 results in a decrease in Bacillus subtilis spore inactivation. The spore reduction could be read directly as
 a function of dose and transmission, for different flows treated in the same reactor. The work of Sommer
 and Cabaj as presented in Exhibit 2-26 is important because it provides a view of the range of practical
 application of ultraviolet light in water disinfection under various flow conditions.  In  any case, it is
 important that actual flow through an ultraviolet unit does not exceed the manufacturer's recommended
Tflow rate.                                    •                                  ,

 2.3.4  Small System Design Considerations
 Ultraviolet equipment  varies in design.  Minor design details may have significant  effects  on operation
 and disinfection capabilities of the ultraviolet light unit.  Therefore, onsite testing of the equipment may
 be recommended to determine whether the unit is properly designed for a specific quality of water. It is
 UV Light Disinfection Technology in
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  Exhibit 2-26. Practical Application of Ultraviolet Light in Water Disinfection, Surrogate
                 Used Bacillus subtilis (Source:  Sommer and Cabaj, 1993)
           Reduction [log]
  Dose mWs/cm2
        5-
        4-
        3-
        2
        n

                  80
                  65
                  50

                 35
                  20
IS Im3/h]
2.5 (ma/hl
3.5lm3/h)
4.5lm3/hl
           0    10   20    30    40    SO   60   70    80
                  Transmission (10 cm; 254nm) %
recommended also that an engineer design the disinfection system or that an independent third party test
the efficacy and reliability of the equipment under various raw water conditions.  Testing an ultraviolet
unit should include efficiency tests under low flow conditions, high flow conditions, low quality water,
and for multiple lamp units, simulation of a situation where one or more lamps are not functioning.
(Efficiency tests involve injecting a bacterium stock [challenge microorganism] at a steady rate into the
reactor and assaying the effluent to determine surviving population.)

For small ground water applications, ultraviolet systems should consistof multiple units rather than one
unit, even if one is capable of carrying the entire design flow. Backup or dual units serve the purpose of
maintaining a continuous disinfection process while a unit is being serviced.  Also, a system with multiple
units can shut down a unit during low flow.  Therefore, at a niinimum, two ultraviolet units should be
provided per system with each unit capable of carrying peak hourly flows.

For a small public water system, it is recommended that all electric fittings be of the modular type in order
to make installation, replacement, and  maintenance  quick and easy.  It is also important that the
manufacturer provide information on the unit's theoretical and mean residence time at specific flows, as
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  well as information on peak design flow, ultraviolet transmission assumptions, and minimum dose at the
  end  of the lamp's  life.  Operation manuals should include a description of control systems, alarm
  functions, records, and reports.             >

  The manufacturer should provide an equipment operation plan that includes procedures and intervals for
  cleaning sleeves, frequency of lamp replacement, and frequency of calibration of monitoring equipment.
  The operator of the  ultraviolet unit should be well informed about the location, access, and quantity of
  a backup supply of lamps, ballasts, and Other critical components. Contingency plans for emergencies that
  necessitate a complete shutdown of the ultraviolet system should be drafted before the system is up and
  running.

  For small ground water systems installing an ultraviolet unit, the operators should consider the following:

        •  The ultraviolet system should be installed in a place that would permit free movement around"
           the unit and ample space for service (lamp and sleeve removal, periodic cleanup).
        -An ultraviolet unit should be equipped with before-and-after shutoff valves, and the housing
           should have a drain close to the ultraviolet unit to minimize the  amount of water the service
           personnel will encounter upon opening the unit for service.
        •  Cleanliness of an ultraviolet reactor is an important operation and maintenance issue; therefore,
           continuous intensity monitoring is recommended to detect fouling of the system.

 Operators of small public water systems should at a minimum do the following:

        • Check fail-safe devices for proper operation.
        •  Calibrate me ultraviolet intensity measuring periodically for proper sensitivity.
        -  Disconnect the unit and clean the lamps by wiping with a soft cloth moistened with ethanol
          (APHA, 1989) or any other solvent recommended by the manufacturer.
        •  Inspect and/or clean the ulterior of the ultraviolet chamber every 6 months.
        •  Examine seals annually (and then calibrate the intensity meter). Replace the lamps if they emit
          less than 70 percent of initial output.;
           '  '                     -•                           f
        •  Monitor water  turbidity  and  color  since they are  natural barriers to the transmission  of
          ultraviolet  light.   Also,  some dissolved minerals have  a  tremendous effect on ultraviolet
          absorbance. For example, iron as low as 1  ppm may increase absorbance of ultraviolet li^ht
          by more than 80 percent  (Weber, 1989).
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 Operators of very small ground water systems are not typically in the treatment plant on a daily basis and
 are not expected to be on duty 24 hours a  day.  Therefore, it  is recommended that the operator be
 equipped with a remote system (telemetering) that at a minimum can provide  alarm signals for major
 ultraviolet light  system failure.                                             .

 Major or high priority alarm systems are alarm systems that are initiated by a unit failure or a component
 failure that might result in an unacceptable level of disinfection. Major alarms, as opposed to minor
 alarms, are those alarms that would sound or flash in case of ultraviolet lamp failure, power failure, unit
 failure, or ballast failure. Minor alarms are those alarms that would indicate the failure of equipment that
 does not affect the disinfection process directly  such as a light-emitting diode failure.  Many ultraviolet
                                                                                               i
 light systems are equipped with automatic treatment plant shutdown in case of a major equipment failure.

 In its comment on the Draft EPA GWDR, AWWA suggested that ultraviolet light systems be.required to
 have the following minimum operational controls and procedures:          •

       • A central display showing indicators and alarms for power failure, lamp failure, hours of lamp
         operation, low ultraviolet dosage, high lamp temperature, high ballast temperature, and high
         system flows.              '    -          .
       • Systems that monitor lamp temperature, ballast temperature,  and system water flows.
       •• A photodiode sensor to monitor ultraviolet dosage at 254 nm. A minimum of two sensors per
         unit is recommended. These sensors must be'calibrated using  approved standards each time the
         lamps are cleaned or replaced or the ultraviolet chamber is serviced;                  •
       • Automatic ultraviolet system by-pass or shutoff to be activated whenever peak design flow rates
         are  exceeded, when ultraviolet dosage is low, or when lamp  or ballast temperatures are high.
       • System redundancy should be provided for  the average flow when the largest unit is out of
         service.                                                                 ...•/..,

To assess ultraviolet disinfection viability for small drinking water treatment systems, an evaluation should
be made  of system flexibility, reliability, complexity, and effectiveness. Ultraviolet systems in modular
units are easy to upgrade, accommodate flow expansion plans in phases, and are easy to maintain and
service.  For ground water situations where water quality does not fluctuate as much as surface water
quality, ultraviolet systems are reliable and can perform well if properly maintained.
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          «>                     .               -.--   ,                .1              ,       .
       Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

  Modern ultraviolet light systems are less complex than early ultraviolet models. They are easier to install,
  requiring only one electrical connection and two plumbing connections.  Changing lamps in modern
  models is no more difficult than changing a fluorescent light bulb.

  For small, ground water systems, particularly TNC and NTNC  water supply systems, ultraviolet
  disinfection systems may be more appropriate than chlbrination and ozonation, when the ground water is
  high in THM precursors, for the following reasons:


         • Ultraviolet light does not generate THMs.

         • For disinfection, ultraviolet light is pH and temperature independent.

         • Ultraviolet light is effective in inactivating many pathogenic bacteria and viruses and at higher
           doses is effective against protozoa.

         • There is no danger of overdosing.

         •  There are no safety precautions to  be taken for transporting, storing, or applying chemicals.

         • Environmental impacts from ultraviolet systems are lower'than impacts related to the use of
          chlorine or ozone.

        • The equipment is reliable and easy to maintain.  Many  manufacturers provide equipment
          warranties  and transmission performance warranties.
                               '.         .           i            ••           ' - .
        • Process control is flexible and simple.                         •

        • Overall, operation and maintenance costs are low.

        • There is no need for daily measurement of chemical dose.

        • There is no need to prepare fresh stocks of disinfectants (as. is the case when using sodium or
          calcium hypochlorite).
                         ' ..     •      '          .        -           -      N .    '         '
Following are additional factors that should be considered in the design and operation  of an ultraviolet
facility.

2.3.4.1   Inspections and Shutdown

For  small water systems using ultraviolet light for  disinfection, it is important  to. maintain a clean.
ultraviolet unit and conduct periodic inspections of all monitoring  devices.  Adequate training of the
ultraviolet unit operator is essential, and emergency plans should be in place in case of a ultraviolet system

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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  shutoff.  If a shutdown occurs, emergency plans must ensure that positive pressure is maintained in the
  water supply network to prevent infiltration and cross-contamination and to provide for fire protection.

  2.3.4.2   Distribution System             ,
  For small ground water systems installing ultraviolet units for disinfection, it is important to exercise good
  sanitary practices, particularly if ground water contains dissolved organic compounds (DOCs) and natural
  organic matter (NOM). It is recommended that these systems flush the distribution network, particularly
  dead ends, before installing ultraviolet units and at least once or twice  in spring through summer when
 temperatures rise. Flushing and cleaning the system is recommended to remove accumulated sediments
 and reduce biofilm accumulation in the pipe network, reservoirs, and storage tanks.  Both sediments and
 biofUm contain essential substrates that will increase the likelihood of microbial reactivation (as discussed
 in section 2.4.2).                                 .

 2.3.4.3  Monitoring Devices
 .Regular calibration of monitoring devices and checking key components for. proper functioning are
 important steps to avoid any sudden shutdown or malfunction.  For example, in some cases the Light-
 Emitting Diode (LED) may not give a true indication of whether the ultraviolet lamp is actually operating.
 Therefore, checking for a faulty LED, burned out LED, or malfunctioning ballasts  should be  done
 regularly.

 2.3.4.4  Manuals and Instructions
 Instructions for installation, operation, maintenance, and initiation of service should be provided with each
 system and component. Compliance with Federal, State, and local engineering, manufacturing, and safety
 laws and regulations must be ensured.  For example, power should be automatically switched off whenever
 a unit is opened for service to protect maintenance workers', eyes. Manuals provided by the manufacturer
 typically include drawings and lists of parts for ease of identification and for ordering replacement parts.
 Because ballasts of ultraviolet lamps may provide a different electrical potential difference (voltage) than
 those available for fluorescent lamps, operators of ultraviolet units used in water disinfection should not
use ballasts  other than those specified for use with ultraviolet lamps.
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,       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  2.3.4.5  Spare Parts and Disposal
'  Many small systems, particularly in remote areas, should have at a minimum a set of spare parts that
  includes ballast, lamps, and sleeves. All ultraviolet systems operators, particularly small system operators
  in remote areas,  should  follow the manufacturers' disposal and recycling  guidelines for ultraviolet
  mercury-containing lamps, ballasts, and sleeves.

  General operation  and maintenance practices are well documented in Chapter VI of Microorganism
  Removal for Small Water Systems, USEPA, 1983. In addition, ultraviolet system operators should follow
  the specific operation and maintenance practices for ultraviolet units that are documented in Chapter VH
  of Design Manual: Municipal Wastewater Disinfection, USEPA, 1986.

 2.4    OTHER CONSIDERATIONS RELATED TO THE USE OF ULTRAVIOLET
        LIGHT FOR DRINKING WATER  DISINFECTION
 This  section discusses issues related to ultraviolet treatment in drinking water. It presents  scientific
 findings on by-products formation and removal of organic contaminants from ultraviolet-treated drinking
 water.  It discusses the issues of microbial reactivation, residual disinfection, and availability of a
 challenge  surrogate microorganism.  Finally,  this  section presents efficiency comparisons  between
 ultraviolet light and chemical disinfectants.
  .- •           .            ,           ,                             '                 •
 2.4.1   By-Products Formation  and Removal of Organic Contaminants by Ultraviolet
        Light Treatment
 This section discusses the potential for by-products formation and removal of organic contaminants during
 the ultraviolet light disinfection process.  The effect of ultraviolet light on organic compounds is the result
 of two mechanisms. The first mechanism is the direct action of ultraviolet light on the chemical bonds
 of the targeted organic compounds.  The second mechanism is the action of ultraviolet  light on water
molecules and dissolved oxygen that results in the formation of powerful oxidizing agents, such as ozone
and hydrogen peroxide, which in turn react with the targeted organic compounds and destroy them.

Disinfection processes that result in chemical by-products  that are harmful or that might contribute to
microbial growth should be controlled to minimize  the presence of adverse chemical by-products in
drinking water. More details on prganics removal are presented in Appendix A.  Section 2.4.1.1 provides
information on the removal of known organic contaminants in drinking water by ultraviolet light. Sections
2.4.1.2, 2.4-1.3, and 2.4.1.4 provide information available on by-products formation.

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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 2.4.1.1  Removal of MX and Other Contaminants from Drinking Water
 In a study conducted in Japan, Fukui et al. (1991) used an 18-watt, 30-cm long low-pressure ultraviolet
 lamp to treat an aqueous solution containing a high potency Ames mutagen 3-chloro-4-(dichloromethyl)-5-
 hydroxy-2(5H)-furanone (MX). MX is a known by-product of the drinking water chlorination process.
 One milliliter of the solution was placed in  a petri dish 30 cm below the lamp and irradiated for 60
 minutes. The removal rate of MX was 76 percent, and its mutagenic potency was reduced by 79 percent.
 The researchers found that the hydroxyl radicals1 formed as by-products of the ultraviolet irradiation were
 not responsible  for the removal  of MX.   When ultraviolet irradiation effects  on  MX removal  were
 compared to those of oxidative treatments, including H2O2  and ozone in the presence of iron ions and
 thermal treatment, ultraviolet light treatment  proved more effective than thermal treatment (59 percent
 removal) and reductive treatments.  However, the researchers noted that thermal treatment is useful for
 drinking water application if boiled water is kept in a thermos jar more than 60 minutes, which is a
 practice shared by many Japanese in the work force.              •

 Beltrfn, Garcia-Araya, and Acedo,  1994,  conducted  experiments on atrazine removal by ultraviolet
 irradiation.  The researchers concluded that mainly hydroxyl radicals are responsible  for the oxidation of
 atrazine.  Therefore, atrazine-containing drinking water will be oxidized by ultraviolet light-generated
 hydroxyl radicals  during  the disinfection  process.  However, quantification of atrazine oxidation by
ultraviolet light needs further investigation to determine the dose-degradation relationship and the effects
 of chemical and physical water quality parameters oh the process.

Nick et  al. (1992) noticed that many herbicides do not absorb ultraviolet light above 240 nm and that only
those herbicides that contain an aromatic ring or similar chromophore may degrade at wavelengths above
240 nm. Nick et al. (1992) showed that a conversion of more than  10 percent of atrazine, simazine,
promazine, and terbuthylazine by  photodegradation did not result in mutagenicity (using the Ames test),
even when the irradiated material was applied in high concentrations.  Therefore, ultraviolet photolysis
                                                        i
of triazine herbicides did not give rise to new equally or more hazardous compounds.

At a low ultraviolet light dose of  25 mWs/cm2, four triazine herbicides in drinking water degrade by up
to 5 percent (Nick et al., 1993). Adding hydrogen peroxide and/or ozone to the water to be treated for
organics control (before applying  ultraviolet light) increases the reduction rate of contaminants (Frances,
   'Hydroxyl radicals are formed by the portion of ultraviolet light emitted by mercury:containing lamps at 185 nm.
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  1989; Berglind, Gjessing, and Johansen, 1979).  A high pH of approximately 10.3 to 10.5 also improves
  total organic carbon (TOC) reduction rates (Xu et al., 1989).

  Li et al., 1996, studied the effects of ultraviolet light (30-watt low-pressure lamp) on a 2 percent humic
  acid (a major organic compound  in natural water) solution.  The test results of Li et al., 1996, show a
  decrease in humic acid TOC (15 to 5 mg/L in about 375 minutes) and almost a complete loss of the
  yellowish-brown color of the solution.

  Awad, Gerba, and Magnuson (1993) conducted a demonstration-scale study to determine the effectiveness
  of ultraviolet light in disinfecting reclaimed water. During the pilot testing doses of 45 and 147 mWs/cm2
 were evaluated.  Samples .from the influent and effluent of the pilot unit were collected and analyzed for
 by-products, as presented in Exhibit 2-27.

           Exhibit 2-27.  Results of Disinfection By-Products of Ultraviolet Light
                            (Awad, Gerba, and Magnuson, 1993)
Parameter
Influent
Effluent
(45mWs/cm2)
Trihalomethanes, |ig/I
CHCI3
CHBrCL,
CHBr2CI
CHBr3
Total
0.88
0.13
0.11
0.19
1.3
0.61
. 0.11
ND
0.18
0.9
Effluent
(147mWs/cm2)
-
0.78
0.12
0.10
0.15
1.2
Aldehydes, ug/I - ' "
Formaldehyde,
Acetaldehyde
Heptaldehyde - • . -
Benzaldehyde
Glyoxal
Methyl glyoxal •
TOC, mg/l
UV absorbance
@254.nm, a.u./crh
Bromide mg/l
Bromate, mg/l
8- to 16-carbon hydrocarbons
, 3.54
5.94
ND
ND
2.55
1.25
8.27
0.173
0.11
<0.005
5.90
7.29
- ND
ND
2.73
1.26
8.60
0.165
0.11
<0.005
9.62
8.34
ND
ND
3.44
1.56
8.61
0.165
0.10
<0.005
2 log reduction was observed due to ultraviolet light treatment
Detection limits are 0.1 ug/I for trihalomethanes and 1 ug/I for aldehydes
As can be seen from the exhibit, some increase in formaldehyde, glyoxal, and acetyldehyde compounds
occurred,  with formaldehyde concentration  almost tripling at a dose  of  147 mWs/cm2., Another
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 observation  is that some trihalomethanes removal occurred at 45 mWs/cm2 and at 147 mWs/cm2.
 Formaldehyde is aBl carcinogen i.e. probable human carcinogen with limited evidence in epidemiological
 carcinogenicity  studies (based on inhalation exposure).   The  health advisory  for  the contaminant
 formaldehyde is 1 mg/L for a lifetime exposure for a 75 kg adult, and 20 mg/L for long-term exposure.
 For a 10-kg child, the longer-term health advisory for formaldehyde is 5 mg/L (USEPA, 1996). Therefore,
 the increases are insignificant and do not pose any known health risks. Moreover, it is unlikely to find
 formaldehyde in drinking water sources. (USEPA, 1996). There are no health advisories for acetyldehyde
 and glyoxal (USEPA, 1996).

 In a comparative study of highly concentrated effluents from nine wastewater treatment plants, Jolley et al.
 (1982) determined that the chemical effects of ultraviolet irradiation at 60 mWs/cm2 were relatively slight,
 with the elimination of mutagenic constituents in one effluent.              '

 As stated earlier, Oppenheimer et al. (1993) conducted a study on by-products formation in reclaimed
 water in California.  Compared to chlorination, ultraviolet light has minimal by-products formation and
 some contaminants removal  effect. Exhibit 2-28 shows that ultraviolet light either reduced or slightly.
 increased the concentrations  of some trihalomethane compounds.

 Exhibit 2-28.  Disinfection By-Products Found in Chlorinated and UV-lrradiated EVMWD
                        Tertiary Effluent (Oppenheimer et al., 1993)
Compounds Detected
4-methyl-2-pentanone
Chloroform
Dichlorobromomethane
Dibromochloromethane
Methyl Bromide
Bromoform
Before Disinfection
(H9/I)
5.4
2.7
0.9
1.1
2.8
<0.5
Chlorine" (iig/l)
5.9
21
22
<1.0
<1.0
3.1
uVftig/l)
4.5
2.9
1.0
0.8
<1.0 ,
<0.5
4 Chlorine = 9.8 mg/l dose and 2-hour contact time
" UV = 300 mWs/cm2
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       Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  2.4.1.2  Effects of Ultraviolet Light Treatment on Assimilable Organic Carbon
  Assimilable  Organic Carbon (AOC)2 compounds are  best described as  ready-to-eat substrate for
  microorganisms.  Therefore, the presence of AOC in drinking water may result in rapid increases in the
  microorganism population in the distribution system.  The relationship between the growth of coliform
  bacteria and AOC in finished water is well documented (USEPA, 1992a). The effects of AOC in treated
  drinking water can  be seen in biofilm growth in distribution systems and in episodes of high levels of
  coliform and nuisance bacteria in distribution systems. The following paragraph presents a preliminary
  literature review of the findings on the issue of AOC formation  in ultraviolet-disinfected water.

 The effects of ultraviolet light on the AOC of Pseudomonosfluorescens strain P 17 (AOC P 17) have been
 reported in an American Water Works Association-Research Foundation (AWWARF) publication. At low
 intensities of ultraviolet light sufficient to cause 1 to 2 log reduction of colony counts on a nutrient-poor
 nonselective medium, small increases of the AOC P 17 concentrations were observed (AWWARF, 1988)
 as shown in Exhibit 2-29. The literature search did not find any more recent studies on the effects of
 ultraviolet light at higher doses on AOC formation. Evidently, extrapolation from these limited data may
 not be reliable.  However, these data remain significant for assessing any future research needs in the area
 of ultraviolet light effect on drinking water quality.

  Exhibit 2-29. Effects of Ultraviolet Radiation on  AOC Concentration (AWWARF, 1988)
Log Reduction3 of
Colony Count
1.2
2.0
1.9
0.0
1-2
0.76
0.71
1.25
0.77
AOC (P 17)" ngr ac-Ce eq/l
Before UV
2.0
2.0
4.4
1.7
1.6
3.7
3.6-
4.3
4.4
After UV
2.8
2.8
7.0
1.9
1.6
4.5
3.9
4.4
5.4
 Colony counts (CFU/ml) streak plate method on diluted peptone meat extract agar incubated at 25°C for 10
days.                          ;               '
 Average values of duplicate measurements.
cac-C—acetate carbon.
   2AOC = Assimilable Organic Carbon.  Carbon in organic compounds that are easily biodegradable by a specified
microorganism.  These compounds •include proteins, peptides, amino acids, carbohydrates, carboxylic acids, and other
compounds that are components of the living biomass.
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      Chapter 2—Assessment of Ultraviolet Light Efficacy. Viability, and Operational Factors
 2.4.1.3   Effects on Nitrite Formation
 Groocock (1984) of the Derwent Division of the Severn-Trent Water Authority in the United Kingdom
 reported an average of about 1 percent conversion of nitrate to nitrite (as N) occurring with two ultraviolet
 light units used in the Derwent Division of the Severn-Trent Water Authority. The early experiences with
 ultraviolet light use in drinking water suggest that there can be some conversion of organic nitrogen and
 nitrate to nitrite due to the effect of radiation.of below 240 nm.  Groocock (1984) suggested the use of
 lamp envelopes made from  materials  that absorb wavelengths  below 240 nm (such as Vycor from
 Corning) in cases of high nitrite production. However, these envelopes have a higher rate of solarizatioh
 (thus preventing light from passing through) than the common envelopes and therefore a shorter effective  '
 lamp life.
       *
 In a more recent research, von Sonntag and Schuchmann (1992) concluded that by-product formation is
 of minor importance and significance.  The researchers discussed as an example the formation of nitrites
 from nitrates caused by ultraviolet application at doses used to disinfect water. However,  the researchers
 did not provide any data or citations to support the given example.  ,

 2.4.1.4   Effects on Mutagenicity Before and After Ultraviolet Light Application to River
          Water .
 Zoeteman et al. (1982) studied the mutagenic activity associated with by-products formed by drinking
 water from the Rhine River disinfection with chlorine, chlorine dioxide, ozone, and ultraviolet light at a
 dose of 120 mWs/cm2. The study showed that ultraviolet light application does not affect the mutagenicity
 level of Rhine River water. Prior to 1982, most of The Netherlands' drinking water was not chlorinated.
 Even part of the drinking water derived from polluted surface waters was distributed without chlorination
 when bank filtration was applied (Zoeteman et al., 1982).  The study by Zoeteman et al. (1982) shows
 that few compounds are formed and that some destruction of compounds occurs by ultraviolet irradiation.
 The study showed that some unidentified  compounds were formed by ultraviolet irradiation and that a
 known carcinogen, benzene, was detected at a level, of 1 ug/1.  There were no  more recent studies that
 confirmed the Zoeteman et al. finding of benzene formation in ultraviolet treated drinking water.
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  2.4.2  The Phenomena of Photoreactivation, Dark Reactivation, and Chemical
         Reactivation.                               .
  Ultraviolet radiation causes damage to nucleic acids. This damage is not always permanent.  Exposure
  of some damaged microorganisms to visible light (400 to 750 nm) reverses the damage, provided that the
  exppsure to the visible light occurs shortly after the exposure to ultraviolet light (Gaudy and Gaudy,  1980;
  Salle, 1973).  This is known as photoreactivation.  Also, exposure to visible light before exposure to
  ultraviolet light for inactivation reduces the damage in some microorganisms.  Environmental factors such
  as temperature and pH are. also important in the process of reactivation.  The reactivation phenomena
  associated with the use of ultraviolet light for wastewater disinfection may imply, to some extent, that the
  inactivation is temporary and hence  not an appropriate technology for drinking  water  disinfection.
  Therefore, it is important to present the issues surrounding microorganism reactivation mechanisms and
 the research conducted to investigate this phenomena.

 The key to the reactivation process in irradiated microorganisms is the presence of repair enzymes in the
 cell.  The speed at  which a microorganism can recover depends on the growth mechanisms. Spores and
 slow-growing microorganisms are less affected by ultraviolet light than fast-growing microorganisms.  In
 a fast-growing microorganism, the original DNA in a rapidly replicating active cell is lost to the changes
 caused by ultraviolet light before any repair activity could start.  When the cell is no longer exposed to
 ultraviolet radiation (at 254  nm wavelength), excited P/.(jc) electrons in not fully damaged DNA strands
 in slow-growing microorganisms will return to a lower energy state.  Under favorable conditions, the
 microorganism will repair the damaged sections using the cell's enzymes and resume replication activities.
 A detailed explanation of the physical action of ultraviolet  light on  chemical bonds is presented  in -
 Appendix B.

 Viruses do not have repairenzymes, and thus, theoretically, their inactivation is easier than the inactivation
 of bacteria or protozoa.  However, if a.virus is living as a parasite in a bacteria or  protozoa,  then the
viability of the virus, is subject  to the reactivation of the host cell.   In  other words, if the host  cell
reactivates, then viruses protected by the host cell will resume their activities as soon as the host  cell
reactivates.  The same principle applies to infectious bacteria inside a protozoa, such as Acanthamoebae
spp. or Cryptosporidium spp., where, upon photo or chemical  reactivation, the parasites may become a
source of bacterial contamination _(King et al., 1988).
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 The problems associated with photo reactivation and dark repair mechanisms have been studied since 1948
 (Witherell, Solomon,  and Stone,  1979).  It has been shown that microorganisms that are not fully
 destroyed  by ultraviolet light could be revived by exposure to long  wavelength light (visible  light of
 wavelength between 400 nm and 750 nm).  The degree of reactivation in visible light is a function of
 temperature, pH, and time and intensity of the exposure to visible light (Lamanna and Mallette, 1965).
 The longer the irradiated cells are kept in the dark, the fewer the number of cells reactivated in visible
 light  The degree of recovery possible is dependent on ultraviolet light dose. The greater the dose, the
 smaller  the population  of  the  cells  that  reactivate.   Temperature  effect was observed  in  the
 photoreactivation process. The warmer the cells during exposure to visible light, the greater the proportion
 of reactivated cells [up to a temperature of 45°C to 50°C (113°F to 122°F)] (Salle, 4 973). Exhibit 2-30
 shows the difference in the surviving fraction in four microbial species. As can be seen from  Exhibit
 2-30, the difference in the surviving fraction  (in this experiment of Kelner, 1949) of dark-kept arid light-
 kept irradiated cells ranges from 2 logs to 5  logs.

  Exhibit 2-30.  Surviving Fraction in Four Microbial Species After Ultraviolet Irradiation

Dark survival3
Light survival"
S. griseus
2.1 x10'6
6.6x1 0-1
E.coli
4,5x1 0'6
i:2xicr1
P. notatum
5.5x1 O^4
2.5x1 0'1 '
S. cerevisiae
1.px1Q-5
I.OxlO"3-
'Surviving cells kept in dark after exposure to ultraviolet light.
"Surviving cells after illumination with long wavelength light following exposure to ultraviolet light.
Source: Kelner, 1949, as cited in Lamanna and Mallette, 1965.
Cells irradiated by ultraviolet light may be reactivated by chemical means.  The chemical reactivation
phenomenon and the importance of the type of culture and media in which the  microorganisms are
irradiated have been observed since 1927. Bedford (1927) (as reported in Salle, 1973) irradiated growth
media and discovered the formation of hydrogen peroxide. This discovery is important because it .means
that the ultraviolet light dose inactivation rate relationship in a growth medium that produces hydrogen
peroxide as a by-product cannot be used for design purposes in drinking water application. Wyss et al.
(1948) (as reported in Salle [1973]) found that the addition of enzyme catalase would negate  the effects
of hydrogen  peroxide formed by  irradiation.  Addition of compounds  such as nicotinamide-adenuie
dinucleotide (NAD) and coenzyme A as well as pH adjustment can counter the effect 'of ultraviolet light
irradiation.  For example, reducing the pH from 8 to 5 within 2 hours  after irradiation increased the
number of survivors producing colonies of Escherichia coli by as much as 1 x 103  (Weatherwax, 1956,
as cited in Salle, 1973).                               ,          .
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 - '    -       j •             •             -a.           . i """ .     ^^^^^™"^^™""*"^"'*1"^^™""«"^^""^—«^^^^«^^—i^^^»«»
  Groocock (1984) discussed the issue of reactivation and repair mechanisms of microorganisms treated with
  ultraviolet irradiation.  One of these repair mechanisms (photorepair) is encouraged by exposure within
  2 to 3 hours of ultraviolet treatment to higher wavelength radiation, notably above 300 nm, i.e.,  in the
  ultraviolet long wavelength band/visible bands.  This would appear to be largely due to reversal  of the
  dimerization of pyrimidines  (chiefly  thymidirie)  caused by irradiation.   "Dark repair", mechanisms,
  however, exist—particularly where only one strand of the double link has been affected.  Enzyme action
  snips out  the damaged length and then uses the remaining undamaged strand as a template in  the
  reconstruction.  Groocock (1984) argued .that it would  seem likely that  the nucleic acids need  to be
  damaged in more than one place (i.e., more than one photon strike) to ensure permanent inactivation.
  Therefore, a dose threshold will probably be reached before this happens to any great extent.  Ellis (1991)
  cited Angehrn and Trager in their disbelief that reactivation and repair mechanisms are possible under
  operational drinking water conditions.  Ellis  (1991) cited Angehrn and Trager in reporting that no  cases
  of reinfection resulting from photprepair mechanisms have been proved in effectively treated drinking
  water.

 -The experience gained from using ultraviolet light  to disinfect wastewater shows that photoreactivatiog
 is seasonally influenced. During  the summer season (because of less cloud cover, because the northern
 hemisphere is directly facing the sun, and because of longer daylight time and higher cell temperature),
 a maximum repair of :i to 2.5 log increase in total coliforms, fecal coliforms, and Escherichia coli has
 been observed in ultraviolet-treated wastewater (USEPA, 1992b). Whitby and Palmateer (1993) conducted
 experiments to test the significance of photpreactivation in ultraviolet-treated wastewater. The researchers
 used labeled Escherichia coli in their experiment. -After ultraviolet treatment, the photoreactivated labeled
 Escherichia coli were detected in glass bottles but not in the receiving stream. The researchers concluded
 that in the natural environment, photoreactivation is not an important issue. Under operational wastewater
 conditions, microorganisms receiving insufficient ultraviolet dose (because of shielding as well as other
 wastewater quality  factors) may reactivate. The insufficiently ultraviolet-hit cells exhibit the state known
,as biostatic activity.  As stated earlier, biostatic  activity is a term that indicates inhibited metabolism.
 Some of  these cells do reactivate as they come hi contact with visible light as soon as they leave the '
 ultraviolet realtor, and as stated earlier, the faster the cells are put in a favorable environment the more
 likely  that  they will recover.   Under operational  ground drinking water conditions, with sufficient
 ultraviolet dose, it is very doubtful that many cells will be in the biostatic state.  It is very doubtful that
 cells in the biostatic state will be able to reactivate as soon as water is drawn from use from the faucets
 because there is some residence time spent in the dark closed distribution system.
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 The reactivation of microorganisms that have been subject to disinfection is not unique to the process of
 ultraviolet light disinfection. Because disinfection as a process is not sterilization, microorganisms injured
 by chemical disinfection and not completely destroyed can revive (as microorganisms disinfected with
 ultraviolet light do) under favorable conditions. At insufficient-to-kill chemical disinfectant concentrations,
 the disinfectant may cause the microorganisms .to go into a state known as biostatic activity. In a. biostatic
 state, metabolism is inhibited and that sets the microorganisms on a course that with time leads to death.
 The effect of the insufficient-to-kill chemical concentration could be reversed if the microorganisms were
 placed in a more favorable environment.  At concentrations lower than the concentrations sufficient to
 trigger the biostatic state in microorganisms, no inactivation effect of any kind may be exhibited, and with
 various disinfectants or microbial poisons a very small concentration may stimulate growth (Gaudy and
 Gaudy, 1981). The problems associated with reactivated microorganisms range from biofilm growth in
 drinking water distribution systems (USEPA, 1992a) to sicknesses that often go unreported as water-related
 (USEPA, 1984).

 To nunirnizephotoreactivation of microorganisms in ultraviolet treated drinking water, if proved to happen
 under operational conditions, four possible approaches that need further investigation may be followed:

        1.   Provide ample disinfection arid attenuation time (residence time in the ultraviolet reactor by
             reducing  the  flow rate, adding another in-series ultraviolet  unit, or  providing  a closed
             reservoir  immediately after the ultraviolet unit). This additional attenuation timemight not
             exceed few to tens of seconds, but is crucial for inflictirig greater damage on the genetic
             material of slow-growing microorganisms.
        2.   Increase the intensity and/or use a shorter wavelength emitting lamp (185 nm) along with
             the standard 254 nm emitting lamp (combine a low-pressure mercury lamp with a medium-
             pressure mercury lamp) to provide a broader range of germicidal wavelengths that include
             ozone, peroxides, and free radicals producing wavelengths.
        3.   In extreme cases use ozone or hydrogen peroxide or both for disinfection prior to ultraviolet
             to increase the disinfection power of the reactor, particularly  when high levels of organic
             compounds or assimilable organic compounds are present, and follow that by a GAC filter
             to eliminate any residual by-products.
        4.   Find the most appropriate disinfection wavelength for specific recalcitrant microorganisms
             and use the custom manufactured lamp that emits it, in addition to the low-pressure mercury
             lamp.

 2.4.3   Ultraviolet Light and Residual Disinfection
 Groocock (1984) noted, from the experience of the Severn-Trent Water Authority in the United Kingdom,
, that a small amount of ozone is produced by radiation at wavelengths below 200 nm, thus giving a slight
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       Chapter 2— Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  .enhancement and prolongment of the germicidal action.  In a 20-month pilot plant study, Lund and
  Ormerod,  1995, found that ultraviolet treatment had an inhibitory  effect on biofilm formation.   The
  inhibition effect of ultraviolet light is thought to be the 'result of hydrogen peroxide and/or other oxygen-
  containing free radicals produced by irradiation. Gjessing and Kallqvist (1991),  as cited in Lund and
  Hongve, 1994, reported the inhibition of Selenastrum capricornutum alga growth in ultraviolet irradiated
  water that  lasted for several weeks.  It is known that free radicals and oxygen species formed during
  ultraviolet are very reactive and snort lived, but H2O2, one of the known ultraviolet irradiation by-products,
  has a half-life in water ranging from 1 to 8 hours in natural  water and more than 80 hours under sterile
  conditions  i.e. H^ half-life is water quality dependant.  (Cooper and Zepp, 1990 as cited in Lund and
  Hongve, 1994).
 Lund and Ormerod, 1995, investigated the effects of chlorination, ultraviolet light treatment and ozonation
 on biofilm formation in water distribution systems. The ozonated test water received an ozone dose of
 1.8 ± 0.4 mg/L.  The ultraviolet irradiated water received a 42 mWs/cm2 dose.  The chlorinated water
 maintained a free residual chlorine level of at least 0.05 mg/L after a 30 minutes contact time. The control
 test water did not receive any treatment other than straining. The average values of the physicochemical .
 properties of tested water at the Baeram water treatment plant near Oslo, Norway are presented in Exhibit
 2-31. Exhibit 2-31 includes the  number of samples taken during the 20-month pilot study.

    Exhibit 2-31.  Baerum Average Water Quality Parameters (Lund and Ormerod, 1995)
Parameter
Turbidity (NTU)
pH
Color (mg Pt/L)
DOCa (mg C/L
Feb(ug/L)
Mn(ug/L)
Total N (mg N/L)
Total P (u,g P/L)
Number of Samples
146
95
94
24
40
36
15
14
Mean Value
0.4
6.4
35
4.6
128
36
0.34
4
Standard Deviation
0.06
0.16
5.2
0.76
23.5
7.6
0.05 r
0.8
aNo pronounced seasonal variation
"Maximum values in August 1988 and August 1989
All raw water used in the experiments of Lund and Ormerod, 1995 was strained with a 35 um mesh size.
The raw water pipe was forked into four laterals, one for control and one for each of the three disinfection
treatments. After the application of treatment at the head of each lateral pipe, the waters were pumped
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 at a flow rate of 0.20 to 0.25 I/s into 2.6m pipes of 20.4 mm inner diameter.  The lateral pipes used in
 the experiment were high density polyethylene (HDPE) pipes. Each of the four lateral pipes had pieces
 of mica held inside the HDPE pipe by a fitted-in poly vinyl chloride (PVC) pipe.  The pieces of mica were
 held in a position parallel to the flow of the tested water. Water samples were withdrawn on a monthly
 basis for measuring Biochemical Oxygen Demand (BOD), ultraviolet absorbance, and Dissolved Organic
 Carbon (DOC) content.                                                            •

 Forqualitative'characterization of thebiofilms formed, Lund and Ormerod, 1995 examined the mica pieces
 using an electron microscope.  The microscopic inspection of the mica pieces showed  that mica from
 chlorinated water was colonized by rod-shaped bacteria assembled in star-shaped colonies. The mica from
 the other three systems (control, ultraviolet treatment and ozone treatment) were colonized by rod-shaped
 and budding bacteria.  Extracellular polymer substances were not evident in the chlorinated system but
 were evident in the other three systems (forming networks on the mica surface) most in the ozonated
 system and least in the ultraviolet irradiated system.

 The BOD test results showed that ozonated water had the highest BOD level (10% higher than the control
 BOD level) which indicated an  increase in the content assimilable organic carbon. Ultraviolet irradiated
 water showed 70 percent less BOD than the control.

 Lund and Ormerod, 1995, noted that biofilm formation started early in the experiment, but amounts of
 sludge, measured as dry weight, were hot produced until the water temperature started to rise above 5°C
 in May.

 Exhibit 2-32 presents seasonal accumulation of biofilm measured as dry weight. The biofilm formed in
 ultraviolet irradiated water was  similar, but not identical, to the "biofilm found in the control system.
                                                                           ;

 Lund and Ormerod, 1995, concluded that prevention of biofilm formation in distribution systems is best
 done by removing as much as possible for the organic material (mean value of DOC in the treated water
 was 4.6 mg/L) from the source water and maintaining a low free  chlorine residual  in the distribution
 system.

To summarize, the test results of the 20-month pilot study by Lund and Ormerod showed that no biofilm
formed in the pipes carrying chlorinated water.  It also showed that the highest biofilm formation occurred
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

      Exhibit 2-32. Seasonal Accumulation of Biofilm, Measured as Dry Weight  in the
         Different Pipe Systems and Seasonal Variations in Raw Water Temperature
     	.                  (Lund and Ormerod, 1995)
                                                                     a .
                              FMAM J-J AS OND J FMAM J JASON
                            JFMAMJ J AS OND J F.M.AM J J A S O N;

                                      1988               1989
* Microstrained system
o Onzonated system
                              4 Ultraviolet irradiated system
                              D Chlorinated system
                     Periods with stagnant water
                     in pipe systems
in the pipes carrying  ozonated water followed by control  water.  The pilot study also showed that

ultraviolet-treated water formed considerably less biofilm production than the control water.


Lund and Hongve (1994) investigated the phenomena of bactericidal effect of ultraviolet-irradiated water. '•

To confirm that ultraviolet treatment yield a durable bacterial growth inhibitory effect, Lund and Hongve,

1994, conducted a series of experiments aimed at determining the duration of that inhibitory effect and

aimed at determining the residual bactericidal effect of ultraviolet treatment. The researchers used water
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 from Bserum waterworks near Oslo (Exhibit 2-33) and irradiated separate volumes with 42 mWs/cm2 and
 96 mWs/cm2. Heterotrophic bacteria inoculum was added to the ultraviolet treated water. Water samples
 were drawn after one minute and 60 minutes of inoculation for enumeration of surviving bacteria. The
 test results show that 7 days after ultraviolet irradiation, heterotrophic bacterial  growth was inhibited.
 Exhibit 2-34 presents the test results as reported in Lund and Hongve (1994). The researchers found that
 approximately 60 percent of the heterotrophic bacteria inoculum in the water samples from the pilot plant
 near Oslo, Norway, were inactivated within 1 hour of contact time with ultraviolet disinfected drinking
 water.                                                               .    *
         Exhibit 2-33.  Baerum Water Quality Parameters (Lund and Hongve, 1994)
Parameter
DOC (mg/0
UVjj* absorbance (per cm)
Color (mg Pt/l) =
PH .
Fe (mg/l)
Ca (mg/l)
Mn (mg/l)
Alkalinity (mmol/l)
Conductivity @25°-C (mS/m)
Level
3.9
0.17
30
6.4
0.01
• 3
: 0.35 ,
0.05
' 2.7
   Exhibit 2-34. Demonstration of Long-Term Inhibitory Effect in U.V.-lrradiated Water
            Compared to Raw Water, After Addition to Heterotrophic Bacteria
                                 (Lund and Hongve, 1994)
Storage Time of
U.V. Irradiated
Test Water at
4*C (days)
0
0
7
7
14
14
Contact Time
Between
Bacteria and
Test Water
(min)
1
60 .
1
60
1
60
Bacterial Counts (CPU/nil)
95% Conf. Intervals*
Normal U.V.
Dose
430±87a .
540±85m
4,056 ± 232"
2,570 ± 185"
overgrown
overgrown
High U.V. Dose
440 ±67
463 ± 79
4,'920±314
4,035 ± 284
overgrown
overgrown
Reduction in Bacterial
Concentration
Normal U.V.
Dose
42mWs/cm2
66%
57%
22%
51%
0%
0%
High U.V. Dose
96 mWs/cm2
, 65%
63%
5%
22%
0%
0%
* Poisson distribution model.
* Initial cone, was 1,250 £ 105 CFU/ml.
" Initial cone, was 5;200 ± 100 CFU/m!.
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       Chapter 2-Assessment of Ultraviolet Light Efficacy. Viability, and Operational Factors
  Over a period of 7 days, the growth curves for heterotrophic bacteria in inoculated control raw water and
  irradiated water samples, show an exponential growth after the first day of inoculation.  The growth rate
  for control samples is significantly higher than the growth rate in irradiated water.  The growth rate in
  control samples are double the rates of treated water samples. The water samples were stored in the dark
  at 4°C. The difference in results between the42 mWs/cm2 irradiated water and the 96,mWs/cm2 irradiated
  water is statistically insignificant (Lund and Hongve, 1994).

  Also Lund and Hongve, 1994, conducted  tracer studies to  measure metabolic inhibition and  replication
  inhibition of microorganisms in ultraviolet irradiated humic water. The researchers used 3H-labelled
  thymidine and leucine as a tool to quantify cell growth and replication  in ultraviolet-irradiated water.
  Leucine is knowii to be incorporated in the  DNA of active bacteria during protein synthesis and thymidine
  is known to be incorporated in the DNA when the cell is multiplying. The uptake of leucine and thymidine
 by a microorganism is dependent on  the presence of biodegradable organic substances: The physico-
 chemical properties of the humic water used in the tracer studies are presented in Exhibit 2-35^

  Exhibit 2-35. Water Quality  Parameters of the Basrum water used in Tracer Experiments
   	                    (Lund and Hongve, 1994)
                       Parameter
                                                                        Level
  DOC (mg/l)
                                                                          7.8
  UVg54 absorbance (per cm)
                                                                          0.30
  Color (mg Pt/l)
                                                                        60
  PH
                                                                         7.4
  Fe (mg/l)
                                                                         0.5
  Ca (mg/l)
  Mn (mg/l)
                                                                         0.08
  Alkalinity (mmol/l)
                                                                         0.3
  Conductivity @25°C (mS/m)
                             2.7
The tracer experiments were conducted on 0.2um filtered control water. In addition to the control samples,
the water samples were either preheated to 70°C or irradiated with an ultraviolet dose of 240 mWs/cm2.
Exhibit 2-36 shows bacterial uptake of 3H-labeled leucine in treated and control water samples.  The
uptake rates of Leucine in irradiated water compared to the uptake rates in control water show that
ultraviolet light has an inhibitory effect on bacterial growth.

Experiments on microorganisms uptake of 3H-labelled thymidine in ultraviolet irradiated water and control
of water samples during 24 hours were conducted with various volumes of added inoculum.  Exhibit 2-37
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  Exhibit 2-36.  Bacterial Uptake of 3H-Labelled Leucine in Water Samples with Identical
                       Inoculation Volumes (Lund and Hongve, 1994)*
             4 i—
         55.  3
         u
         CO
         W

         CO
         H.
         D
                                                  A
                                                  A
                                                  a
                                                  a
A
A
d?
                                 -H-
                                      50
                           100
ISO
                                              Minutes
 + Ultraviolet irradiated water samples (240 mWs/cm2)
 * Heated water samples (70°C)
 n Sterile filtered water samples (0.2 um)  '
 * Inoculants were prepared using 100 times the concentration of a chemically treated sewage effluent.
presents thymidine uptake test results. As can be seen from Exhibit 2-37, a near constant 3H-labelled
thymidine uptake levels for the control samples -are attained.  Lund and Hongve, 1994, attributed this
uptake inhibition, i.e., cell reproduction inhibition, to a micronutrient limitation. Exhibit 2-37 shows that
3H-labelIed thymidine uptake levels-in ultraviolet irradiated water samples are consistently lower than the
uptake levels in all the control water samples.    '                                           /

Lund and Hongve noted that ultraviolet irradiation alone may inhibit biofilm formation in new and clean
distribution  systems  and may prevent adherence of organic matter  on the  walls  of pipes in short
distribution systems.  However, Lund and Hongve 1994 cautioned that the inhibitory effect of ultraviolet
irradiated water may be very limited in distribution systems with well established biofilm or water high
in biodegradable organic substances.
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       Chapters-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
   Exhibit 2-37. Bacterial Uptake of 3H-Labelled Thymidine During 24 Hours in Ultraviolet-
      Irradiated and Untreated Control Samples for Various Volumes of Inocular Added
     • •                             (Lund jand Hongve, 1994)*
                    15 r—
                 u
                 o
                 to
                 >S
                 O
                .«
                 0.
                    10 -
                     5  -
                                             |  1 u.v.-irradiated water
                                             R53 Raw water
                                                          BJ
                           0.2
0.6          1.8  .,   5.1
 Inoculum, % of total volume
                                                                         14
  * The inoculated suspension was prepared using  100 times the concentration of particulate organic
    matter extracted from the same water.
 As stated earlier, ultraviolet radiation produces hydrogen peroxide in irradiated water. Lund and Hongve,
 1994, believe that the residual disinfectant effect in ultraviolet-irradiated waters is due to hydroxyl radicals
 produced as a by-product of hydrogen peroxide reaction with reduced compounds such as ferrous iron in
 humic compounds.  Lund and Hongve, 1994, allude, to the fact that oxygen species radicals produced in
 some disinfection processes such as ozonation, can give rise .to more biodegradable substances and hence
 surmised that ultraviolet irradiation may to some degree enhance bacterial growth in humic water.

 2.4.4   The Search for a Surrogate
 Because traditional surrogate microorganisms (e.g., total coliform)  are sensitive to ultraviolet light, and
 because it is not economically feasible to test every target pathogenic microorganism, an appropriate
 surrogate microorganism is needed to quantify the  correlation of its  inactivation rates  to  that of
 microorganisms  of interest, such as reoviras, rotavirus, or  Hepatitis A virus (HAV).  Therefore, the
 viability of ultraviolet technology  depends to  a certain extent on the  identification  of a surrogate
microorganism that is  suitable and reliable in quantifying ultraviolet efficacy against pathogenic micro-
organisms commonly found in ground water sources.
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      Chapter 2—Assessment of Ultraviolet Light Efficacy. Viability, and Operational.Factors
 Wilson et al. (1993) proposed the use of coliphage
 MS-2  as a challenge surrogate microorganism to
 test the efficacy of ultraviolet light.   The  main
 reason for his proposal is the similar reaction to
 chemical  and ultraviolet treatment exhibited  by
 MS-2 and members of the genus enteroviruses that
 includes  polioviruses, Norwalk,  and  Coxsackie
 virus.  Wilson et al. (1993) compared the ultra-
 violet inactivation results of, MS-2 to those of a
 variety of waterborne pathogens (see Exhibits 2-10
 and 2-11). The work of Wilson et al. (1993) shows
 that a 99.5 percent inactivation (2.3 log reduction)
 at 39.4 mWs/cm2 of MS-2 using ultraviolet light is
 equivalent  or greater than 6 log reduction  of
 Klebsiella Terrigena, vibrio cholerae,  Salmonella
 typhi,  Escherichia  coli   0157:H7,  Shigella
 dysenteriae, Yersinia enterocolitica, Campylobacter
jejuni,  Aeromonas. hydrophila,  and  Legionella
pneumophila. For the same (2.3 log) reduction in
MS-2, using ultraviolet light, a 4 log reduction was
obtained in HAV, rotavirus SA-11, and poliovirus
type  1.   In  this study, Wilson et  al.  (1993)
concluded that a minimum of 6 log reduction in all
of the above-mentioned pathogenic bacteria could
be achieved using an ultraviolet light dose of 15.6
mWs/cm2  and that  a 39.4 mWs/cm2 minimum
ultraviolet  dose  was  necessary  to   achieve  a
           Surrogates:  An "EPA Perspective
     Many problems are associated with trying to detect
     specific pathogens: Because of these problems,
     bacteria that are not themselves pathogenic are
     measured as surrogates for the more harmful
     bacteria. The ideal indicator for drinking water
     contamination is:
     •  Suitable for all types of drinking water
     •  Present in polluted water at higher concentrations
       than harmful bacteria
    „•  Able to survive in water at least as long as
       pathogens and is at least as resistant to
       disinfection
     •  Easy and inexpensive to measure in drinking
       water samples
     •  Generally not present unless harmful
       contamination is also present.
     (USEPA, 1992a)
minimum of 4 log reduction in the tested viruses.
         Surrogates: A German Perspective
    In Germany, drinking water is assumed to be
    microbiologically acceptable when coliform bacteria
    or E. coli are not detected in water samples.
    Carlson (1991) suggested specific requirements for
    microorganisms to be acceptable as surrogate
    indicators for microbial contamination:
    •  The microorganisms must.be present in large
       numbers.
    •  They must  be easily and reliably detected with
       routine methods.
    •  Their survival period should correspond at least
       to that of the pathogenic organism in question.
    The last requirement presents a problem because
    some pathogens, like certain viruses, remain
    infectious in the environment for longer periods than
    bacteria. As presented by Carlson (1991), the
    German view for selecting a surrogate vindicator
    microorganism is very close to the USEPA
    perspective on the subject, but not as specific as the
    USEPA point of view:        .               ,
Exhibit 2-38 presents  the bar graph inactivation
rates.  The work of Wilson et al.  (1993) may be
considered in the Agency's technical review for a
ground water disinfection requirement using ultraviolet light. However, it is worthwhile to consider that
UV Light Disinfection Technology in
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2-60
Final—September 1996

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        Chapter 2-Assessment of Ultraviolet Light Efficacy. Viability, and Operational Factors
         Exhibit 2-38. Extrapolated Inactivation Rates for Bacteria, Viruses, and Test
                         Surrogate Cbliphage MS-2 (Wilson et ai., 1993)
                99.9999%
   Inactivation*   99.99%
                   99.5%
                                                                            so        UV Dose
                                                                                  (mW sec/cm2)
                                                                                022E-16
    Inactivation rates extrapolated using linear regression model
 the above-cited 6 log and 4 log reductions presented in the bar graph in Exhibit 2-38 were concluded by
 extrapolation.  To extrapolate and estimate ultraviolet'doses, Wilson et al. (1993) used a linear regression
 analysis software (Statgraphics® Version 5.1,1991) to develop an MS-2 linear regression model (no tailing
 factor is considered) based on the data presented in Exhibits 2-10 and 2-11. From the linear regression
 model, ultraviolet light dose estimates with 95-percent confidence intervals were calculated using a one-
 tailed t test. It is important also to note that all challenge microorganisms and the proposed surrogate
 microorganism were tested in phosphate-buffered distilled water.  Phosphate-buffered distilled water media
 may have lower ultraviolet demand than does naturally occurring water. .In addition, naturally occurring
 microorganisms are typically more  resistant to disinfection than laboratory-cultured microorganisms.

 Wilson et al. (1993) argued in favor of adopting coliphage MS-2 as a surrogate microorganism because
 (1) it is more resistant to ultraviolet light than all the tested pathogenic bacteria and viruses; (2) it has
 highly reproducible ultraviolet light inactivation results;  (3) the cost is low; (4) high liters are easily
 attainable;  (5) it shows results  within 6 hours; and  (6) it is not pathogenic to humans.   Moreover,
 coliphage MS-2 requires 18 to 24 hours to culture.
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                                                                         Final—September 1996

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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
 Sommer and Cabaj (1993), realizing that lab-cultured microorganisms are more sensitive to disinfection,
 proposed criteria for selecting a suitable surrogate microorganism. The microorganism that satisfies these
 criteria would then be used to test the efficiency of ultraviolet light disinfection in drinking water.  The
 proposed criteria call for a microorganism with the following characteristics:

        •  A steady inactiva'tion over a wide dose
        •  A simple and sufficient culturability
        •  Nonpathogenic
        •  A temporal stability with regard to ultraviolet susceptibility.

 Sommer and Cabaj (1993) proposed a specific cultural procedure (method C) for Bacillus subtilis spores
 (ATCC6633) that satisfies the above criteria.  The proposed cultural procedure (presented previously in
 Exhibit 2-11) is not the same cultural procedure required under ANSI/NSF Standard 55-1991 for the same
                                                               c
 challenge microorganism Bacillus subtilis spores and was selected after two other cultural procedures
 failed to satisfy the proposed criteria (refer to Exhibit 2-11 for more details). Bacillus subtilis spores
 require 3 days to culture (method C).  The test results of its susceptibility to ultraviolet light are highly
 reproducible.

 2.4.4.1   ORP, a Non-Microbial Surrogate
 Carlson (1991) addressed the issue of microbiological water examination in Germany.  According to the
 provisions of the Bundes-Seuchengesetz  (Federal Communicable Disease Act), proving the existence of
 bacterial pathogens requires special permission from the authorities. Moreover, it is a time-consuming
 process, and it is impractical if not impossible for a public water system to get sampling test results before
 the water is pumped into the distribution network or consumed. The fact that various pathogenic bacteria
 actually lead to an outbreak after a long incubation period further complicates the issue of microbiological
 examination of water. For example, the incubation period of HAV infection is 15  to 50 days depending.
 on dose, with an average of 28-30 days.  A 1- to 3-week incubation is needed to have typhoid fever
 symptoms (APHA, 1981). If an operational error or system failure allowed the pathogens causing HAV
 infection or typhoid fever to be waterbome through the distribution system to the consumer, it would take
 at least 15 days before the first case of HAV infection would be reported  and a minimum of 1 week
before the first case of typhoid fever would be reported.  Thus, if water is examined  for the pathogen
                                                                         I
causing the typhoid fever.dt is more than likely that the microorganism will not be found because it would
have been flushed out of the system during the incubation period. Because of-the impracticality.of testing
UV Light Disinfection Technology in
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
  all pathogens that might exist in drinking water, surrogate challenge and indicator microorganisms are used
  to test disinfection  efficiency.   Still, testing for these surrogate microorganisms is time consuming,
  requiring skills that  might not be available in operators of small and remote water systems.

  Because the Oxidation  Reduction Potential (ORP)3 of  the medium  plays an  important part  in  the
  physiology and ecology of microorganisms, the metabolism of a microorganism and, consequently, its
  ability to survive and propagate are influenced by the ORP of the medium in which it lives.  The range
  of the ORP at which bacteria can live is limited, with anaerobes propagating in medium to low levels and
  aerobes in the low to high ORP levels. The inability of anaerobes and aerobes to survive at high ORP
  levels can be explained by the fact that the SH groups  (these are highly oxidizable groups that play an
  important role in electron transfer mechanisms in microorganisms) or radicals-containing enzymes, within
  the microorganism will be inactivated at high levels of ORP.  For microorganisms,  like all life forms
  including humans, placing them in  direct contact with an extreme  environment will be detrimental.
 Therefore, the elimination of microorganisms in drinking water can be achieved by high ORP, so that the
 vital enzymes are blocked. Appendix B of this report describes how ultraviolet light  is used to achieve
 high levels of ORP in polluted drinking water sources.  Carlson (1991) argued in favor of using ORP as
 an indicator of disinfection efficiency.  The researcher presented studies  that correlate the killing rates of
 pathogenic organisms to ORP levels. The studies .conducted by Carlson (1991) to determine ORP levels
 at which chlorination would  result in a satisfactory disinfection show that ORP  levels above 700 mV
 versus a saturated calomel electrode at pH 7 should be maintained  for at least 10 to 30 seconds. If this
 proves to be reliable, it will be easier to train water works operators on how to place an ORP probe in
, finished water and take a continuous reading than to take a water sample and to test for microbial presence
 on an occasional basis.

 2.4.5  Comparison of Ultraviolet Light to Chemical Disinfection
 Because it is not economically feasible to require public water supply systems to test for every pathogenic
 microorganism that might be present in drinking water, surrogate microorganisms are tested for and used
 as indicators of microbial water quality and disinfection.  'Traditional indicator surrogate microorganisms
    Oxidation is defined as the addition of oxygen tp a compound, the removal of a hydrogen, or the loss of a pair of
 electrons (Gaudy & Gaudy, 1980).  Reduction is the removal of oxygen from a compound, the addition of hydrogen, or
 the addition of a pair of electrons. In an oxidation-reduction reaction, a potential is formed at'a submersed platinum
 electrode by supplying and accepting electrons. This potential is measured by using an electronic voltmeter without
 drawing current against a reference electrode (saturated calomel electrode or silver-silverchloride electrode). The difference
 in potential between the reference electrode and the metal at which the oxidation and reduction reaction takes place is
 referred to as the ORP.                    •'/,'•

 UV Light Disinfection  Technology in
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      Chapter 2—Assessment of Ultraviolet Light .Efficacy, Viability, and Operational Factors

 (e.g., total coliform, Escherichia coli microorganisms) are sensitive to ultraviolet light. Therefore, it would

 be inappropriate to compare the inactivation rate of ultraviolet light and those of traditional chemical

 disinfectants for those indicator surrogate microorganisms.  Moreover, quantified comparison of chemical

 doses (in mg/L) and  ultraviolet light doses (in mWs/cm2)  for specific microorganism inactivation rates

 cannot be established at this point. However, when comparing chemical disinfection with ultraviolet light

 disinfection, a few issues stand out:
        • Cryptosporidium spp. is resistant to chemical disinfection and cannot be inactivated using
          chlorine or ozone at doses normally used for drinking water disinfection (USEPA, 1993).
          Therefore, for ground water contaminated with Cryptosporidium spp., chemical disinfection has
          no advantage over-ultraviolet light.

        • The 1991 Article 80 of the Uniform Fire Code (UFC) requires treatment systems to handle the
          accidental release of chlorine gas, chlorine dioxide, or sodium chlorite, as well as  provide
          emergency power sufficient to operate chemical scrubbing equipment (WERF, 1995). These
          new requirements may well double the costs of chlorination (gas type)  systems in States that
          require compliance with the UFC.                             .

        • For small systems where space is not available, or where capital and construction experience
          is not available,  ultraviolet systems  are useful in  upgrading and retrofitting with minimal
          construction work.  An ultraviolet unit can disinfect 0.5 MOD in a 40 ft2 space (USEPA, 1983)
          while a chlorination unit requires more than 1,000 ft2 space, assuming a 30-minute contact time
          and a flow velocity of 0.1 ft/sec.

        • Unlike chemical disinfection, there are no known risks associated with oversizing the unit and
          there is no limit on the dose that could be applied.  These qualities  give ultraviolet  light an
          edge over chemical disinfection in water applications where disinfection by-products pose health
          risks,  and their production is sensitive to chemical dose.

        • At proper dose applications, ultraviolet light systems are effective in  destroying bacterial and
          viral pathogens.  •    .                                                .


Exhibit 2-39 compares the germicidal effects of ultraviolet light with chemical disinfectants (Yip and

Konasewich, 1972).  Using fecal coliform log reduction as a yardstick to measure the number of yardstick

units required by chlorine, ozone, and ultraviolet light to achieve the same log reduction for a number of

pathogenic microorganisms, Yip and Konasewich (1972) showed that ultraviolet light is  comparatively

more effective than  chlorination and ozonation  with  about the same relative dose requirement  for five

different pathogens other than Escherichia coli.  However, another study by Chang et al. (1985)  showed

that ultraviolet light is less effective.


Chang et al. (1985)  address the issue of using coliforms as a valid indicator for disinfection efficiency

using ultraviolet light Based on the relative dose required to disinfect pathogenic organisms (see Exhibit

2-40), they concluded that the survival rate of coliform bacteria hi ultraviolet irradiated effluents does not
UV Light Disinfection Technology in                                                    .
Drinking Water Application—An Overview     2-64                       Final—September 1996

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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
    Exhibit 2-39.  Germicidal Effects oj Ultraviolet Light Versus Chemical Disinfectants in
                   Drinking Water Applications (Yip and Konasewich, 1972)
I
. *•
£4
!»
-L

•

o
uvao. a
III Tl



c
1
uv



1
0

•
c

...
uv
1
1




a


pj

u
V



UVCI
1
' .- * ? 4 5 ''•«.'
(1) EKberidila coll B C8) Salmonella fyphou
(9)Stapbjiococctuaaretu(4)Pollotypelvinu
CO CtaMdde AZ vinu («) Adenorlras lype S.
 directly reflect the level of disinfection needed to disinfect the more resistant organisms.  The ultraviolet
 light resistances of viruses and Escherichia coli as reported by Chang et al. (1985) are not as comparable,
 as implied by Yip and Konasewich (1972) (see Exhibit 2-39).  The Yip and Konasewich 1972 study
 showed a comparatively uniform ultraviolet light disinfection capability against a variety of pathogenic
 microorganisms, while Chang et al. showed a nonuniform ultraviolet light disinfection capability.  For
 example, Kip, and Konasewich  (1972) found that Escherichia  coli and poliovirus require the same
 ultraviolet dose to achieve the same log reduction.  Chang et al. (1985) found that the poliovirus requires
 more than three times the ultraviolet light dose-applied to  Escherichia coli to achieve the same log
 reduction.  To compare ultraviolet resistance by  various microorganisms, Chang et al. (1985) proposed
 the use of standardized growth conditions of the  tested microorganisms.

 The advantages of using ultraviolet light rather than chemical disinfection are the following:

        •  No known toxic or significant nontoxic by-products.
        •  No danger of overdosing.
        • Some removal of organic contaminants.
        • If used for volatile organic compound (VOC) destruction, no VOC emissions or toxic air
         emissions result (WWEMAj 1990).           •
        • No onsite smell and no final water product smell.
UV Light Disinfection Technology in
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2-65
                                                                       Final—September 1996

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      Chapter 2—Assessment of Ultraviolet Light Efficacy. Viability, and Operational Factors
          Exhibit 2-40.  Relative Ultraviolet Light Dose for Some Microorganisms
                                     (Chang et al., 1985)
2
MICROORGANIS


A. eattttanS cyus

.
.... . t A saHK/i* ffntf*



	 | Standard plate eoynt

mm^f^fj ^^m coBwcwt
• \EtcJ*f*MocoU
,^^^J SrtlfftjfO 3QOft9f
~~~\Se*9on99G tyffif
i t i 11 i i

2 4 68 IO 12 14 16
DOSAGE RELATIVE TO El coti = 1
        •  Very little residence time (seconds versus minutes for chemical disinfection).
        •  No storage of hazardous material required.
        •  Minimal space required for equipment and contact chamber.
        •  Taste  is "not- negatively altered,  only  improved, with the  destruction  of some organic
          contaminants and nuisance microorganisms.
        •  Minerals in water are not affected.                         -
        •  No mutagenicity effect using the Ames test.
        •  No or little (disposal of spent lamps or obsolete equipment) impact on the environment.

The main disadvantage of using ultraviolet light for disinfection is that no long-term residual disinfection
is provided, Exhibit 2-41 presents a quick comparison between ultraviolet light and common chemical
processes.

2.5    FINDINGS
Ultraviolet light of sufficient intensity and exposure is an excellent disinfecting agent for drinking water.
However,  because of its limited penetration power at 254 nm,  microorganisms  that are covered with
protective membranes or are parasites in other microorganisms are less affected by the ultraviolet light
intensity and time of exposure needed to kill exposed microorganisms.   Ultraviolet light is suitable to
disinfect clear water at intensities and times of exposure that are feasible to accomplish disinfection rates
UV Ught Disinfection Technology in
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2-66
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       Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
Exhibit 2-41. Ultraviolet Light Versus Chlorination and Ozonation in Drinking Water
Parameter
Tannins, Humus,
Dissolved Organics, and
Colloidal Material
Iron and Magnesium
Suspended Solids
(Turbidity)
pH Effect
Temperature Effect
Mutagenicity
Time Required to
Inactivate Microorganisms
Limits of Solubility at
Normal Temperatures
Microorganism Inactivation
By-Product Formation
Hazardous Material
Storage Requirement
Chlorine
Increased
Demand
Increased
.Demand
Increased
Demand
Varies
Yes
Yes
Minutes
Varies
. Effective
Yes
Yes
Ozone
Increased
Demand
Increased
Demand
Increased
Demand
Little
Yes
Unknown
Minutes
Yes
Effective
Yes
No „
UV
Increased
Demand
Increased
Demand
Increased
Demand
None
No
No
Seconds
N/A
Effective
No
No
Remarks
Increased harmful by-products for both
chlorine and ozone. Some contaminants
removal by ultraviolet light.
Could require pretreatment for efficient
use of ultraviolet light.
Significant suspended solids levels are
not likely in most ground water.
Some chlorine compounds are sensitive
topH. pH is a factor in organics
destruction efficiency by ultraviolet light
Recent research suggests better
inactivation rates at lower temperatures
using ultraviolet light.
. - - •
Ultraviolet light systems have the
smallest space requirement.




 comparable to chemical disinfectants. The successful use of ultraviolet light for disinfection in the food

 industry is a testimony to its feasibility and viability.  In the food industry, ultraviolet light is used to

 sterilize equipment, control surface growth on bakery products, inhibit mold growth and bacterial growth

 in meat-processing plants, and treat water used for the depuration of shellfish and the production of cell
 protein.        '                                       .


 The data reviewed to date clearly show that:


        •  The required inactivation dose for bacteria using ultraviolet light varies from one organism to
          another and within the same species.  Many factors could contribute to this variance:

          — Source of microorganism                              •
          — Age of microorganism
          - Method of ultraviolet dose measurement
          — Medium used                                     -
          - Organic and inorganic  media quality parameters
          - Physical parameters
        •  — initial microorganisms  density
        " - Ultraviolet intensity used
          - Residence time
          - Flow rate.                                              :
UV Light Disinfection Technology in
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
         • The order of disinfection resistance with few exceptions is as follows: bacteria < viruses <
           bacterial spores < protozoan cysts and oocysts, with Gram-positive bacteria being more resistant
           to ultraviolet light than Gram-negative bacteria.
         • Naturally  occurring microorganisms are more resistant to inactivation by ultraviolet light than
           microorganisms cultured in laboratories.
         • Current indicator surrogate microorganisms are more sensitive to ultraviolet light than many
           identified  microorganisms (including viruses) that are of concern in drinking water.
         • In the meantime, two challenge surrogate microorganism candidates appear to be the best to test
           ultraviolet light disinfection efficiency: Bacillus subtilis spores and bacteriophage MS-2.

 Disinfectants, including ultraviolet light, have limitations, such as undesirable interaction with other water
 constituents, lack of residual effect, or O&M costs and problems. In many applications, it might be useful
 to consider the use of multiple disinfectants and water treatment processes.  .An example of the practical
 applicability of multiple use of disinfection treatment can be found aboard cruise ships that use ultraviolet
 light for disinfection (the DHEW guideline dose is 16  mWs/cm2) followed by chlorine as a secondary
 disinfectant for residual effect as per shipboard regulations (USEPA, 1983).   In  England, multiple
 disinfection systems  have been in use for more than  10  years; small systems of up to 2  MGD use
 ultraviolet light for primary disinfection followed by hypochlorite for distribution system residual effects
 (McCarty, 1986).  The new  studies from Norway concluded  that ultraviolet light has some residual
 disinfection effect  although this is believed to be. of very limited effect. For a large number of small
 NTNC and TNC ground water systems, a secondary disinfectant may not be necessary, as these systems
 have no or a small distribution network.    '                                        ,

 As a tool to disinfect drinking water, ultraviolet light is effective against microorganisms. Ultraviolet light
 is not, however, a panacea. For example, if a ground water source is iron-rich, it can cause fouling to the
 ultraviolet light system and, hence, reduce light transmissibility.  Therefore, the water needs to be treated
 before reaching the ultraviolet disinfection unit. Located at the end of the treatment process where proper
 pretreatment is needed  or required, water entering an ultraviolet unit  may be assumed to be  clear and
 contain little or no  suspended  matter or colloids.

 To summarize the data reviewed, the effectiveness of ultraviolet light depends on the proper wavelength,
 the intensity of the  radiation, the exposure time, the distance from the light source to the organism to be
 disinfected, and the water quality. Therefore, any guidelines to be developed for the use of ultraviolet
light for ground water disinfection need to consider the above-mentioned factors. However, based on the
UV Light Disinfection Technology in   •    •
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        Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors
   work of Sommer and Cabaj (1993), a 60 mWs/cm2 ultraviolet .dose-is  sufficient to achieve a 4 log
   reduction in Bacillus subtilis spores.  Based on Harris et al. (1987), a dose of 45 mWs/cm2 is sufficient
  • to achieve a 3 log reduction in Reovirus 1 in buffered distilled water. A dose of 40 mWs/cm2 is sufficient
   to cause a 5 log reduction in poliovirus (Harris, 1986).  The scientific literature review revealed that a
   greater than 2 log reduction of Giardia muris cysts can be achieved using ultraviolet light at a dose of 121
   mWs/cm2. A minimum of 2 to 3 log reduction in Cryptosporidium parvum oocysts can be achieved using
   an ultraviolet light dose of about 8,750 mWs/cm2.:
•  '                 .•          !         ....••               • .               ,
   Some by-products formation is associated  with the use  of ultraviolet light to "disinfect effluent waters.
   However, by-products formation is insignificant in effluent -treatment and extremely insignificant  in
   drinking water applications. Moreover, by-products formation in ultraviolet disinfection processes in water
  and  wastewater application is far less than that produced  with  the use of chlorination or  ozonation.
  Guidance on use of ultraviolet disinfection technology should identify a minimum specific intensity and
  residence time and specify lamp arrangement and spacing based upon principal water quality parameters.

  A breakdown in etiological agents of waterborne disease in outbreaks in the United States between 1971
  and 1977 shows that in ground water systems bacteria accounts for 33 percent (main agents:  Shigella,
  30 percent; S. typhi, 2 percent; arid Salmonella, 1 percent). .HAV conies in second place as a microbial
  agent of waterborne diseases with 3 percent.  Finally, Giardia comes in third place with Jess than  1
  percent. -Other agents of waterborne disease include chemical agents  (6 percent) and unknown agents (58
  percent) (USEPA, 1993b).  The non chemical-related waterborne disease outbreaks in all water systems
  resulted in about 130,000  cases of illness between 1971  and 1988 (USEPA, 1993b). The information
  provided in USEPA, 1993, shows that 35 percent of outbreaks of waterborne diseases in the United States
  occurred in non-community water supply systems.  This figure is  very conservative because  of long
  incubation periods and because symptoms of illness often  occur in geographical areas far from where the
  exposure occurred. A study by Moore et al., 1993 shows-that 68 percent of outbreaks (for the 1991-1992
  period) of waterborne disease associated with drinking water occurred in non-community  systems with
  well water being the source in 77 percent of the cases. Therefore,  any form of disinfection in TNC and
  NTNC water systems will greatly reduce the number of outbreaks. The reviewed data clearly  show that
  many pathogenic bacteria (such, as Vibrio choleroe) and viruses (such aspoliovirus'and HAV) associated
  with high morbidity and mortality around the world and that might be found in ground water sources, are
  susceptible to ultraviolet disinfection.  TNC ground water  systems and NTNC ground water systems that
  are not under direct influence of surface water (protozoa free) and that have little or  no distribution
  systems may benefit the most from ultraviolet light application.

  UV Light Disinfection Technology in
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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

 2.6    REFERENCES

 Abbaszadegan M., et al. (1993).  Evaluation of the Disinfection Efficiency  of a Point-Of-Use Water
 Treatment System on Protozoan, Viral and Bacterial Pathogens. Proceedings Water Quality Technology
 Conference; Part I Toronto, Ontario, Canada.  November 15-19, 1992, pp. 399-421.

 ANSMNSF  (1991).   Standard  Number 55,  Ultraviolet Microbiological Water Treatment  Systems.
 American National Standards Institute/National Sanitation Foundation International.

 APHA (1981).  Control of Communicable Diseases in Man.  Abram S. Benenson, editor.  13th ed.

 APHA (1989).  Standard Methods for the Examination of Water and Wastewater.  APHA, AWWA,
 WPCR  17th ed.

 Aquafine (1995).  Aquafine Corporation Brochure.

 Aquafine (1995a).  Aquafine Corporation. Personal Communication  with Mr.  Bak Srikanth, Senior
 Application Engineer.  July 1995.

 Atlantic Ultraviolet Corporation (1995). Mighty Pure and Sanitron Ultraviolet Water Purifiers brochures.

 Atlantic  Ultraviolet Corporation  (1995a).  Personal Communication with Ann Wysocki,  Marketing
 Director, September 22, 1995.

 Atlantic Ultraviolet Corporation (1996). Letter from Mr. Hilary Boehme, President, to Mr. Marc  Parrotta,
 OGWDW, USEPA, July 25, 1996.

 Awad, J., Gerba, C., and Magnuson, G. (1993).  "Ultraviolet Disinfection for Water Reuse."  Planning,
 Design,  and Operation of Effluent Disinfection Systems. Specialty Conference Series,  May 23-25,
 Whippany, New Jersey, pp. 1-12.

 AWWA (1992).  American Water Works Association. GWDR Comments.

 AWWARF (1988).   The Search for A Surrogate.   American  Water Works Association Research
 Foundation Cooperative Research Report. 421pp.        .                                     ,,,

 Bank, H.L.,  et al.  (1990).   "Bactericidal Effectiveness of Modulated UV Light."   Applied and
 Environmental Microbiology. Vol. 56, No. 12, pp. 3888-3889.

 Battigelli, D.A., Sobsey, M.D., and Lobe, D.C. (1993).  "The Inactivation of Hepatitis A Virus and Other
 Model Viruses by UV Irradiation." Water Science Technology. Vol. 27, No. 3-4, pp. 339-342.

 Bedford, TJHLB. (1927). "The Nature of the Action of Ultraviolet Light on Microorganisms." British J.
 of Experimental Pathology.  Vol. 8, p. 437 (as cited in Salle, 1973).

 Beltran, FJ., Garcia-Arayo, J.F., and Acedo, B. (1994).  "Advanced Oxidation of Atrazine in Water—H
 Ozonation Combined with Ultraviolet Radiation." Water Research. Vol., 28, No. 10, pp. 2165-2174.

 Berglind, L., Gjessing, E., and Johansen, E. Skipperud (1979). Oxidation Techniques in Drinking Water
 Treatment: Drinking Water Pilot Project, Report 11 A, Advanced Treatment Technology. USEPA ODW,
Washington, DC.  EPA-570/9-79-020.


 UV Light Disinfection Technology in
 Drinking Water Application—An Overview     2-70                       Final—September 1996

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       Chapter 2-Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

  Bryant, E.A., Fulton, G.P., 'and Budd, G.C. (1992).  Disinfection Alternatives, for Safe Drinking Water
  Hazen and Sawyer Environmental Engineers & Scientists. New York:  Van Nostrand.

  Butler, R.G., Lund, Vv, and Carlson, D.A. (1987).  "Susceptibility of Campylobacter jejuni and Yerisinia
  enterocohtica to UV Radiation."  Appl. Environ. Microbiol. Vol. 42, pp. 546-547 (as cited in Sobsey,
  1989).                        '."••".

  Campbell, A.T., Robertson, L.J., and Smith, H-V' (1992). "Viability of Cryptosporidium parvum Oocysts-
  Correlation of in vitro Excystation with Inclusion/Exclusion of Fluorogenic Vital Dyes " Awl environ
  Microbiol.  Vol. 58, pp. 3488-3493.                                                     ..

  Campbell, A.T., et al. (1995). "Inactivation of  Oocysts of  Cryptosporidium parvum  by Ultraviolet
  Radiation."  Wat. Res. Vol. 29, No. 11, pp. 2583-2586.     .                    .    .-

  Capital (1995). Facsimile from Mr. Shaun Pierson of Capital Controls Company, Inc. to Faysal Bekdash
  dated August 3, 1995.

  Carlson, D.A., et al. (1985).  "Ultraviolet Disinfection of Water for Small Water Supplies." Cincinnati
,OH:  U.S. Environmental Protection Agency, Office of Research and Development, EPA/600/2-85/092.'

 Carlson, S. (1991). "Fundamentals of Water Disinfection." J. Water SRT-Aqua. Vol. 40, No.  6, p 346-
 356.

 Chang, J.C., et al. (1985).  "UV Inactivation of Pathogenic and Indicator Microorganisms."  Appl Environ
 Microbiol. Vol. 49, pp. 1361-1365.                                                             '

.Chen, C.L.,  and Kuo, J.F. (1992).   UV Inactivation  of Bacteria and  Viruses in Tertiary  Effluent
 Presentation to the DHS UV Disinfection Committee on Research at the County Sanitation Districts of
 Los Angeles County (as cited in WERF, 1995).

 Chick, H. (1908).  "Investigation of the Laws of Disinfection." 7. Hygiene, Vol. 8, p. 92.

 CH2M HILL (1992).   UV Disinfection Pilot Study  - Rapid Infiltrationfcxtraction (RIX) Demonstration
 Project. Prepared for Santa Ana Watershed Project Authority, City of San Bernardino, City of Colton (as
 cited in WERF, 1995).                                                     .'.'.'

 DHEW CDC (1974). Recommendations on Vessel Sanitation (as cited in Witherell, L.E., Solomon RL
 and Stone, K.M., 1979).                                                                   '  ' "'

 Cooper, W.J. and Zepp, R.G. (1990).  "Hydrogen Peroxide Decay in Waters with Suspended Solids-
Evidence for Biologically Mediated Processes." Can. J. Fish. Aquat. Sci., Vol. 47,-pp.  888-893.

Dizer, H., et al. (1993). /'Use of Ultraviolet Radiation  for Inactivation of Bacteria and  Coliphages in
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Ellis, K.V. (1991).  "Water Disinfection: A Review with  Some Consideration of the Requirements of the
Third World."  CRC Critical Reviews in Environmental Control, Vol. 20, No. 5/6, pp. 341-407.
UV Light Disinfection Technology'in                   .
Drinking Water Application—An Overview    2-71                       Final—September 1996

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     Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

FDA (1995). CFR 21 Part 129.8a.. Personal communication with Ms. Shelly Davis of the U. S. Food and
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McGraw-Hill.                                                          .

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Harris, G.D., et  al. (1986). "UV Inactivation of Selected Bacteria and Viruses with Photoreactivation of
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UV Light Disinfection Technology in
Drinking Water Application—An Overview.    2-72                 ;     Final—September 1996

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        Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

   KaraniSi P., et al. (1992).  UV Sensitivity of Protozoan Parasites.  Journal of Water Supply Research and
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 *•          ' '         • '       .        >         -            ' •                        .        •  ''
  Martiny H., et al. (1988).  "Anwendung von UV-Strahlen zur Desinfektion von Wasser. I. Mitteilung:
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  UV Light Disinfection Technology in
.  Drinking Water Application—An Overview     2-73                       Final—September 1996

-------
      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

 Martiny H., Wlodavezzyk, K., and Riiden, H. (1988). Anwendung von UV-Strahlen zur Desinfektion von
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                                                               i
 Masschelein,  WJ. (1989).   "UV-Reactor Geometry'for Water Treatment, Part  2:  Development of
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 Nick, K., et al.  (1992).  "Degradation of Triazine Herbicides, by UV Radiation Such as Used in the
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 NIOSH (1995).  Personal communication with Mr. Gene  Moss.

 NIPH (1989).  A Guidance for the Disinfection of Drinking  Water.  Ultraviolet Irradiation.  National
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NRWA (1992).  National Rural Water Association. GWDR Comments.  2 selected pages. •

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                                                      .  '           ,           ;
 Oda, A. (1969).   Ultraviolet Disinfection  of Potable  Water Supplies.   Ontario Water  Resources
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 UV Light Disinfection Technology in
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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

 ODHR (1992). Oregon Department of Human Resources.  GWDR Comments.  3 selected pages.

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 Quails, R.G., and Johnson, J.D. (1982).  "Bioassay and Dose Measurement in Ultraviolet Disinfection."
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                                                                                  x".
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 Rahn, R.O.  (1970). In Photochemistry ofMacromolecules, Reinisch, R.F.,ed., New York:  Plenum Press,
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                  *         \                   -      .                 .
 Rice, E.W.  and Hoff, J.C. (1981).  "Inactivation  of Giardia lamblia Cysts  by Ultraviolet Irradiation."
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 Severin, B.F., Suidan, M.T., and Engelbrecht, R.S. (1983). "Effects of Temperature on Ultraviolet Light
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 Sobotka, J.  (1992).  "AppKcation of Ultraviolet Radiation for Water Disinfection and Purification in
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 Quarterly Report (as cited in USEPA, 1991).                            :

 Sobsey, M.D.  (1989).   "Inactivation  of Health Related Microorganisms  in  Water By Disinfection
Processes."  Water Science and Technology. Vol.  21, No. 3, pp.  179-195.   '

Sommer et al. (1989). Zbl Hyg. No. 189, pp. 214-224 (as cited in Sommer and Cabaj, 1993).

Sommer, R. and Cabaj,  A. (1993).  "Evaluation of the Efficiency of a UV Plant for Drinking Water
Disinfection."  Water Science and Technology: Vol. 27, No. 3-4, pp. 357-362.
UV Light Disinfection Technology in                                           ^
Drinking Water Application—An Overview    2-75           ,            Final—September 1996

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      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

 Steel, E.W. (1960).  Water Supply and Sewerage. 4th ed.  McGraw-Hill.

 SWS (1996).  Evaluation of the Safe Water Solutions, L.L.C.  Cryptosporidium Inactivation Device for
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 Tobin, K.S., et al. (1983). "Methods for Testing the Efficiency of Ultraviolet Light Disinfection Devices
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 Trojan (1992). Trojan Technologies Inc.  Comments received by USEPA in response to EPA draft
 Ground Water Disinfection Rule dated July 31,  1992.

 USEPA (1983). Microorganism Removal for Small Water Systems.  Office of Drinking Water. - EPA
 570/9-83-012.                .

 USEPA (1984).  Committee on Challenges  of Modern Society (NATO/CCMS), Drinking Water
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 USEPA (1986). Design Manual:  Municipal  Wastewater Disinfection. ORD. EPA 625/1-86/021.

 USEPA (1989).  Technologies for Upgrading Existing or Designing New Drinking Water Treatment
 Facilities.  Office  of Drinking Water. EPA 625/4-89/023.                             '      /

 USEPA (1991). Guidance Manual for Compliance with the Filtration and Disinfection Requirements for
 Public Water Systems Using Surface Water  Sources:  Science and Technology Branch, Criteria and
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 USEPA (1991a): Manual of Small Public Water Supply Systems. Office of Water.  EPA 570/9-91-003.

 USEPA (1992). Draft Ground Water Disinfection Rule.  July 31, Federal Register, Vol. 57, p. 33960.

 USEPA (1992a).  Seminar Publication:  Control of Biqftlm Growth in Drinking Water Distribution
 Systems.  EPA/625/R-92/001.
                                                                   \      '• .
 USEPA (1992b).  UV Disinfection Technology Assessment.  Office of Wastewater Enforcement and
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 USEPA (1992c). Technologies and Costs for Control of Disinfection By-Products (Draft).  Science and
Technology Branch,  Criteria and Standards Division, OGWDW, Malcolm Pirnie, Inc.

USEPA (1996). Drinking Water Regulations  and Health  Advisories.  February.

USEPA (1993) Cryptosporidium,  Drinking Water Health  Advisory.  Health and Ecological Criteria
Division, Office of Science and Technology, Office of Water.

USEPA (ax).   Very Small Systems Best Available Technology  Cost Document.  Drinking Water
Technology Branch,  OGWDW.  Draft Document, Malcolm  Pirnie, Inc.

USEPA (1993b). Technologies and Costs for Ground Water Disinfection.  Drinking Water Technology
Branch, OGWDW. Draft Document, Malcolm Pimie, Inc.
UV Light Disinfection Technology in
Drinfang Water Application—An Overview    2-76                      Final—September 1996

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       Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

 Van Nostrand (1989). Ultraviolet.  Van Nostrand's Scientific Encyclopedia, pp. 2887-2889.

 Voitle,. R. (1994). "Mastering Difficult Ultraviolet Applications." Water Technology, September, pp. 78-
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 von Sonntag, C., and Schuchmann, H.P. (1992). "UV Disinfection of Drinking Water and By-Product
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 Wagenett, L.,  and Lemley, A. (1994).  "When Is It Effective? UV Radiation for Treating Drinking
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 Weatherwax, R.S. (1956).   "Reactivation of Ultraviolet-Irradiated  Escherichia coll" J. Bacteriology
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 Weber, J., Jr. (1989)., Physicochemi'cal Processes for Water Quality Control  John Wiley and Sons.

 WERF (1995).  Comparison of  UV Irradiation to Chlorination: Guidance for Achieving Optimal UV
 Performance Disinfection.  Water Environment Research Foundation.
                                                 i                                        - l

 Whitby,  G.E. (1989). Ultra-Violet Light Disinfection of Water for Small Systems. In Drinking Water
 Treatment Small System Alternatives. Toft, Tobin, and Sharp, eds.. New York: Pergamon Press, pp. 159-


 Whitby,  G.E.,  and  Palmateer (1993).   The  Effect of  UV Transmission,  Suspended Solids, and
 Photoreactivation on Microorganisms in Wastewater Treated with UV Light.- Wat. Sci Tech  Vol 27
 No. 3-4, pp. 379-386.

 Wiedenmann et al. (1993). Disinfection of Hepatitis A Virus and MS-2 Coliphage in Water by Ultraviolet
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 Witherell, L., Solomon, R., and Stone, K.M. (1979).  Ozone  and Ultraviolet Radiation Disinfection for
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 WWEMA (1990),  Study on the Application of Ultraviolet Disinfection for the Potable Water Industry.
 Water and Wastewater Equipment Manufacturers Association, Inc. Comments  on GWDR, pp. 1-5.

 Wyss, O.,  et al. (1948).   "The Role of Peroxide  in  the  Biological Effects  of Irradiated  Broth."
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 Xu, S., et al. (1989). "Treatment of Pyridine Containing Wastewater by Qzonation Under UV Irradiation."
 Ozone in Water Treatment,  pp. 743-750.


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                                                                          ,
      Chapter 2—Assessment of Ultraviolet Light Efficacy, Viability, and Operational Factors

 Yip, R.W., and Konasewich, E. (1972). "Ultraviolet Sterilization of Water, Its Potential and Limitations."
 Water & Pollution Control (Can.), Vol. 110, pp. 6-14.

 ZefF, JJD. (1993). "Testing of a Full Scale UV/Oxidation System to Obtain a Permit for Removing PCE
 from a Drinking Water at a Well Site in the City of South Gate,  California."  Ozone in Water and
 Wastewater Treatment. Vol. 2, pp. S-13-1—S-13-14.

 Zoeteman, B.C.J., et al. (1982).' "Mutagenic Activity Associated With By-Products of Drinking Water
 Disinfection by  Chlorine,' Chlorine  Dioxide,  Ozone and UV-Irradiation."   Environmental Health
 Perspectives, Vol. 46, pp. 197-205.

 Zukovs, G., et al. (1986). "Disinfection of Low Quality Wastewaters by Ultraviolet Light Irradiation."
 J. Wat. Pollut. Control Fed.  Vol. 58,  pp. 199-206.

 Zumdahl, S. (1989). Organic Chemistry. 2nd ed.  D.C. Heath and Company, pp. 264, 869-870, 983.
UV Light Disinfection Technology in
Drinking Water Application—An Overview.    2-78                       Final—September 1996

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  CHAPTER 3.  EVALUATION OF ULTRAVIOLET LIGHT TECHNOLOGY
  COSTS AND  COMPARISON TO OTHER DISINFECTION PROCESSES

 3.1    INTRODUCTION

 Presented in this chapter are findings to date on costs associated with using ultraviolet light to disinfect
 ground water sources of public drinking water.  Cost factors relevant to ultraviolet light disinfection
 include capital costs (i.e., equipment and construction costs) and operation and maintenance costs (i.e.,
 parts replacement, power, and labor costs). Ultraviolet light costs derived from available information are
 presented in section 3.2.  Section 3.3 compares these costs with ultraviolet system cost estimates developed
 previously by USEPA.  Ultraviolet light costs are compared to costs associated with other disinfection
 technologies such as chlorination and ozonation in section 3.4, while the costs of providing secondary
 disinfection (i.e., a residual to  protect distribution systems) are addressed in section 3.5.  Section 3.6
 presents costs from some foreign ultraviolet light systems.

 The ultraviolet light system cost estimates and costing methodology in this report were based on previous
 USEPA cost estimate reports, cost information collected from ultraviolet light equipment manufacturers,
 other USEPA drinking water reports, and articles published in the scientific literature. Cost information
 collected from ultraviolet light equipment manufacturers was used to compare current  market prices with
 previously reported cost  estimates and to compare current ultraviolet costs with the cost of other well-
 established disinfection technologies such as chlorination and ozonation. The costs presented in this report
 are estimates and subject to some variance.  Site-specific considerations, such as influent water quality,
 are a major Variable in cost estimation and would impact the overall cost of the ultraviolet disinfection
 system. In addition, USEPA considers these to be preliminary estimates of cost which will be subject to
 change as cost methodologies, and groundwater disinfection requirements develop.

 The cost estimates in this report are for USEPA flow categories 1 through  5. This includes all U$EPA
 flow categories for small water  systems,  one medium-flow, and one large-flow USEPA category. The
 average flow, design flow, and population served for those flow categories are presented in Exhibit 3-1.

Capital and operation and maintenance costs were studied for two doses: 40 mWs/cm2 and 140 mWs/cm2
at 253.7 nm for USEPA flow categories 1 through 5. The 40 mWs/cm2 dose was selected based on the
work of Harris (1986) that showed a 5  log reduction of poliovirus.  Harris' work was adopted as the base
UV Light Disinfection Technology in
Drinking Water Application^-An Overview    3-1                      Final—September 1996

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           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
          	to Other Disinfection Processes	

                Exhibit 3-1. USEPA Flow Categories and Population Served
USEPA Row
Category
1
2
3
4
5
Average Flow (MGD)
0.0056
0.024
0.086
0.23
0.7
Peak Factor
4.3
3.6
3.1
2.8
2.6
Design Flow (MGD)
0.024
0.087
0.270
0.650
1.80
Population Range
25-100
101-500
501-1,000
1,001-3,300
3,301-10,000
 for ANSI/NSF (1991) standard 55-1991 for Class A POU drinking water disinfection treatment systems.
 The 140 mWs/cm2 dose is the minimum dose required under the National Water Research Institute
 (NWRI, 1993) guidelines for water reclamation (e.g., for agricultural end users) in California.  The NWRI
 (1993) guidelines are based on the works of Chen and Kuo (1992) and CH2M HILL (1992) that showed
 a 4 log reduction of poliovirus in treated domestic wastewater.

 Costs can be expressed as annual costs or costs per thousand gallons of treated water. Costs per thousand
 gallons are helpful in estimating the impact on the consumer's water bill. Both methods of cost expression
 are used in this chapter to facilitate the use of the generated cost figures to assess the impact on the
 consumer's water bill and to assess the national economic impact of using ultraviolet light for disinfecting
 ground water for drinking.

 Costs in this report are based  on the use of modular vessels (closed systems) that require one electrical
 connection and two plumbing connections.  The capacity of modular units is assumed to follow the
 following criteria:

       • There' is a minimum of two units per treatment plant.
       • When one unit is not in service, the other unit(s) have the capacity to carry peak design flow
         (daily or hourly).   The  determination of whether the remaining units should be capable of
         carrying hourly  or  daily peak flow capacity must be based on the system's water storage
         capacity to account for peak hourly demand.

These criteria are based on USEPA's suggested recommendations for the use of ultraviolet systems under
the Draft Ground Water Disinfection Rule (GWDR).                                ,  ,
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-2
Final—September 1996

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            Chapter 3— Evaluation of Ultraviolet Light Technology Costs and Comparison
  _    - -  •        _ to Other Disinfection Processes
  3.2    ULTRAVIOLET DISINFECTION COSTS
                                           -' s               " .   ,
  The total  cost estimate for an ultraviolet system is the sum of two major costs:  capital, including
  equipment cost, and operation and maintenance cost.

  Due to the fact that costs rise and fall in accordance with the economic market, costs need to be adjusted
  to current value. Capital costs are adjusted through the use of the Engineering News Record Construction
  Cost (ENRCC) Index (ENR, 1995).  Operation and maintenance costs are adjusted using the Producer
  Price Index, which  is found in the publication Producer Prices and Price Indexes (PPPI,  1995).  All
  capital costs obtained from earlier reports and used in this:study were adjusted to the August 1995 20-city
  average ENRCC Index value of 5506.33. This average value is not as accurate as a value for a specific
  city  or region of the United States and  may  overestimate or underestimate  costs due  to varying
 construction costs in different parts of the country.  If a specific city or region is known to be the future
 site of an ultraviolet treatment system, the ENRCC index for that city or region should be used.  This
 method of cost adjustment is more applicable to chlorination systems than to ultraviolet systems, because
 ultraviolet systems require very little construction work.                                     '

 Cost data in other literature were updated for comparison with current costs using the following standard
 equation (WERE, 1995):
                 Construction  Cost  = — : - 5506.33 _ _     ReDorted r ^
                                      Reported ENRCC Index     KeP°rte
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                                 to Other Disinfection Processes
 Capital Cost (c/kgal) =
             Capital Cost ($) x Amortization factor x
       lOOc x   1 Year   x   1 MG
        $1  X  365 days  X 1000 Kgal.
                                          Flow (MOD)
3.2.1   Capital Costs
The capital cost for an ultraviolet system is mainly the equipment cost. Capital costs for this quasi "turn-
key" system involve the purchase of equipment and construction (if any) of a protection structure (room
or shed) and installation of the system. These costs depend on several factors, such as flow rate, degree
of treatment, and influent water quality. As flow rate increases, more lamps will be needed to provide
adequate light energy. The equipment becomes larger and more complex, and the cost rises accordingly.
The degree of treatment also affects the cost of equipment. An ultraviolet treatment for drinking water
that is closer to sterilization requires doses that are far higher than the doses required for disinfection.
Therefore, a high degree of treatment could be far more expensive than current disinfection requirements.
By the same token, a "poor" quality water that is high in microorganism densities or in plating and fouling
agents requires more ultraviolet energy to achieve the desired treatment levels.

The degree of treatment considered in this analysis is based on the use of ultraviolet systems  capable of
delivering 40 mWs/cm2 and  140 Mws/cm2 doses to achieve the 5 log reduction of poliovirus  in "good,"
i.e., filtered water sources that are low in plating and fouling agents, and a 4 log reduction of poliovirus
in "poor" water quality sources comparable to a filtered secondary wastewater effluent, respectively.

3.2.1.1   Equipment Costs
The cost estimates presented here are quotes from tiiree manufacturers that have considerable market share
and experience in ultraviolet technology.   The equipment considered for use in small  water systems
includes closed chamber ultraviolet modules  with lamps and quartz sleeves,  module  support  racks,
                                                                        i
instrumentation and control panels, power supply  distribution and ballasts, automatic cleaners, pipes and
valves, and other equipment to control and monitor the system. Through the use of modular systems, the
equipment cost can be calculated easily by estimating the number of modules required.  The cost of
shipping and installation is included in the estimates. It is assumed in this study that all units include self-
cleaning mechanisms.  Prefilter cost, if any, is not included in this analysis. The equipment costs and the
number of modular units and lamps required for  different systems are summarized in Exhibit 3-2. As
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-4
Final—September 1996
-------
           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison

           	•                to Other Disinfection Processes
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                            3-5
                                                                       Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
	to Other Disinfection Processes	   .  	
shown in Exhibit 3-2, the cost range for equipment delivering 40 mWs/cm2 is $8,000 to $143,000 and
$11,000 to $381,000 for equipment delivering 140 mWs/cm2.for flow categories 1 through 5.

3.2.1.2   Construction Costs
Because ultraviolet modules are typically small in size, no major construction costs are assumed in this
cost analysis.  However, a 20-percent markup of the equipment cost is included in total capital cost to
account for engineering (10%); legal, fiscal, and administrative services (3%); sitework and interconnecting
piping (6%); and contingencies (1%), including any minor construction work that may be necessary, such
as a small shed to protect the ultraviolet equipment and its spare parts from the elements. This is shown
in Exhibit 3-3. According to USEPA (1993a), factors such as contractor's overhead and profit, electrical
connections, and standby power should be added to equipment costs to calculate capital costs for all types
of systems.  However, these cost factors are not included here because closed ultraviolet systems resemble
a turnkey job more than  an engineering design, construction, and supervision job.  Also, USEPA (1993a)
states that  electrical work would cost  $1,300 per installed horsepower or approximately  $1,740 per
installed kilowatt.  This is not applicable to  ultraviolet  systems; because  there is little electrical work
involved beyond plugging the system in. In addition, such costs account for comparatively insignificant
amounts.

                  Exhibit 3-3.  Added Engineering and installation Costs
Item i
Engineering
Legal, Rscal, and Administrative
Sitework and Interconnecting Piping
Contingencies
Cost*
10 percent of equipment cost
3 percent of equipment cost
6 percent of equipment cost
1 percent of equipment cost
•Modified from USEPA (1993a).
3.2.1.3   Total Capital Costs
Equipment costs are the major source of capital costs. Therefore, total capital cost is equipment cost plus
20 percent, as detailed earlier. Although sheds, piping, electrical connections, engineering, legal services,
and construction in general do not account for a fixed percentage, the 20-percent markup in equipment
costs allows for variations in prices from one region to another and among different industries. For large
systems, the 20-percent markup might be an over-estimation, thus providing a more conservative cost
assessment of ultraviolet systems. This is illustrated in Exhibit 3-4, which gives, a straightforward total
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-6
Final—September 1996
-------
           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                  '" ' '          to Other Disinfection Processes
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          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
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 of capital costs in dollars and capital costs estimates in cents per thousand gallons for ultraviolet systems

 delivering the two set doses of 40 mWs/cm2 and 140 mWs/cm2 for USEPA flow categories 1 through 5.


 3.2.2  Operation and Maintenance Costs

 Once a  treatment system is in place, costs  are incurred in the  everyday operation of the facility.

 Continuous 24-hour per day operation for the treatment system is assumed.  However, during periodic

 maintenance, a unit can be shut down while another unit or units carry the design flow.  Operation and

 maintenance costs include parts replacement,  electric power consumption, and labor. The subsequent

 operation and  maintenance cost estimates are based  on the following assumptions:


       • The size of the system is based on design flow with redundancy in equipment, i.e., a minimum
          of two module units with each unit capable of carrying design flow; if more than two module
          units are used, then the total number of units minus one unit should be capable of carrying the
          set design flow.

       • Power consumption of lamp and ballast is calculated according to manufacturer's estimates (the
          range is 70 - 85 watts for low-pressure lamp units).

       • Lamp replacement is calculated according to manufacturer's estimates of lamp life at 70 percent
          of its initial efficiency (as measured after 100 hours of service, the range is 8,000 -  14,000
          hours).  -

       • Ballast replacement is done every ten years (worst case assumption).

       • Quartz sleeves are replaced every five years (worst case assumption).

       • Labor is estimated at 0.5 hours per lamp per year for cleaning and repairs. (The range  is 0.25
          hours per year to two hours per year)."                                             •

       • Chemicals  (0.1 gallon per lamp per year) for cleaning once every 6 months (range 6 to 12
          months).

       • Miscellaneous  equipment repair costs are accounted  for at 0.1% of  capital costs with a
          minimum of $15 per year [for repairs such as replacement of a malfunctioning LED].


It is assumed that ultraviolet equipment is disposed of in a safe manner consistent with the disposal of any

electrically driven equipment, such as high-efficiency mercury-containing lamps and fluorescent lamps and

ballasts, and therefore present no significant additional costs. It should be noted that, sqme manufacturers

willingly take back ultraviolet lamps and ballasts for recycling of materials, presumably at no cost to the

water system user.
UV Light Disinfection Technology in
Drinking Water Application—An Overview     3-8                       Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                                to Other Disinfection Processes
3.2.2.1   Parts Replacement
Regular maintenance of equipment is necessary to keep the system operating properly.  Materials in need
of regular replacement in an ultraviolet treatment system include ultraviolet lamps, ballasts, and sleeves.
Based on industry quotes, lamps cost between $40 and $100 each and should be replaced every 8,000 to
14,000 hours.   Ballasts  and LEDs may need to be replaced every  10 years.  Quartz  sleeves and
miscellaneous switches, valves, and rings may need to be changed every 5 years,

Exhibit 3-5 presents part replacement costs for equipment used to provide for the doses considered in this
report. These costs were provided by ultraviolet equipment manufacturers.  Exhibit 3-5 shows that .the
difference in maintenance costs could be significant.  The calculated maintenance costs for manufacturer
"A" are almost twice those of manufacturer "B" for all ultraviolet systems delivering 40 mWs/cm2 and
more  than thrice  the calculated maintenance costs of  manufacturer  "B" for systems delivering
140mWs/cmV              '

3.2.2.2   Power Costs
Power costs are estimated assuming a unit rate of $0.086 per kilowatt-hour (USEPA, 1993b). This rate
is highly variable based .on the geographic location of the facility in the country and the source of electric
power. Power costs are based on the power requirements for each type of lamp and unit as provided by
the manufacturers assuming 24-hour per day operation.
              (             '          **.•                            -
Exhibit 3-6 presents calculated power costs in cents per thousand gallons of treated water for the doses
considered in this report and for USEPA flow categories 1 through 5.

3.2.2.3   Labor Costs
The facility's  labor requirements are for the replacement of parts, general maintenance (cleaning of lamps,
sleeves, and the unit body), and monitoring.  Cleaning requirements are highly site-specific in frequency,
level of effort, and time requirements. For high-quality water, an annual cleaning could be accomplished
by flushing the unit  with a liquid detergent  (approved  synthetic organic detergent,  ethanol, dilute
phosphoric acid, or dilute hydrochloric acid) after recycling it under pressure for a specific time, according
to manufacturer's recommendations.  For low-quality water with fouling and plating problems, a monthly
cleaning might be necessary.  The labor rate is assumed to be $15.50 per hour.  This rate is in August
1995 dollars and is -based on estimates cited by DPRA (1993) fo^ a 10-city average for non-union scale
UV Light Disinfection Technology in
Drinking Water Application—An Overview     3-9                       Final—September 1996
-------
           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison

          	          to Other Disinfection Processes
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                                     3-10
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           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
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UV Light Disinfection Technology in
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3-11
                                                                  Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
 	to Other Disinfection Processes
 laborers.  The hourly rate of $15.50 includes an average salary of $9.15 per hour plus a 12.2 percent
 fringe benefit and a 50 percent labor overhead cost.  Average salaries ranged from $7.65 to  $10.75 per
 hour in the south central and western United States,  respectively.  , Fringe  benefit  rates ranged from
 approximately 8 to 15  percent, depending on the region of the country (DPRA, 1993).

 Based on these .assumptions, Exhibit 3-7 presents labor requirements in hours per lamp per year, total
 hours per year, labor costs per year,  and labor costs in cents per thousand gallons. As can be seen from
 Exhibit 3-7, the labor costs for ultraviolet systems of 140 mWs/cm2 dose capacity are about double those
 required for ultraviolet  systems of 40 mWs/cm2 dose capacity for the same treated flows. Labor costs are
 directly tied to the total number of lamps used in an ultraviolet light system. The increase in labor costs
 between flow  categories 4 and 5  could be traced back to the number of lamps used (see Exhibit 3-2).

 3.2.2.4   Summary of Operation and Maintenance Costs
 Major operation and maintenance costs can be found simply by adding part replacement cost, power cost,
 and labor cost. It may be most appropriate to put major operation and maintenance costs in cents per
 thousand gallons, as this allows for simple estimation of cost based on a plant's flow. Exhibits 3-5 (parts
 replacement costs), 3-6 (power costs), 'and 3-7 (labor costs) are summarized in Exhibit 3-8.

 Exhibit 3-9 presents an itemized  account for total operation and maintenance costs per year and in cents
 per thousand gallons.  All the components of major operation and maintenance costs are  included plus
 miscellaneous  and chemicals costs. The. figures in Exhibit 3-9 are average figures calculated from Exhibits
 3-5, 3-6, and 3-7 according to the assumptions detailed in section 3.2.2.  Where possible, unit prices are
 listed, or a range  is specified or a calculation method is provided. As can be, seen for Exhibit 3-9, for
 every flow category, parts replacement costs constitute the highest  operation and maintenance costs
 followed by power consumption costs.  Labor costs come in third place constituting less than  10 perpent
 of the total operation and maintenance costs /for ultraviolet systems of 140 mWs/cm2 and 40 mWs/cm2 for
 USEPA flow categories 1 through 5.
UV Light Disinfection Technology in
Drinking Water Application—An Overview     3-12 •                  .   Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison

            -  .                 to Other Disinfection Processes
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     3-13
                                                              Final—September 1996
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UV Light Disinfection Technology in
Drinking Water Application—An Overview
                                3-14
                              Final—September 1996
-------
           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison

            -                    to Other Disinfection Processes
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UV Light Disinfection Technology in

Drinking Water Application—An Overview
                                          3-15
Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
 	to Other Disinfection Processes	
 3.2.3   Total Costs of Ultraviolet Disinfection (Capital Costs and Operation and
        Maintenance Costs)
 Total production cost is the capital cost, amortized at 10 percent interest over a period of 20 years, plus
 the operation and maintenance cost. The total cost estimates of ultraviolet systems as per quotes available
 from ultraviolet equipment manufacturers are presented in Exhibit 3-10. Exhibit 3-10 was constructed
 by combining the annualized cost estimates presented in Exhibit 3-4 (capital costs) and Exhibit 3-9
 (operation and maintenance costs). Analysis of total production costs and operation and maintenance costs
 indicate a linear relationship with flow capacity above 0.087 MOD.

                             Exhibit 3-10. Total Current Costs
                                      Dose 40 mWs/cm2
USEPA
Row
Category
1
2
3
4
5
Design
Flow
(MGD)
0.024
0.087
0.27
0.65
1.8
Cost per Year
Total
Capital**
1.30
1.66
3.65
7.68
16.56
Total
O&M
0.38
0.79
1.69
3.70
9.74
k$)
Total
Production
Costs
1.7
. 2.5
5.3
11.4
26.3
Cost (c/kgal)
Total
Capital**
14.80
5.24
3.70
3.24
2.52
Total
O&M
4.32
2.49
1.71
1.57
1.48
Total
Production
Costs
19
8
5
5
4
                                     Dose 140 mWs/cm2
USEPA
Flow
Category
1
2
3
4
5
Design
Flow
(MGD)
0.024
0.087
0.27
0.65
1.8
Cost per Year (k$)
Total
Capital"
1.66
3.63
10.01
16.45
42.05
Total
O&M
0.79
2.05
5.49
9.39
33.98
Total
Production
Costs
2.5
5.7
15.5
25.8
76.0
Cost(cTkgal)
Total
Capital**
18.99
11.42
10.16
6.94
6.40
Total
O&M
8.97
6.45
5.57
3.96
5.18
Total
Production
Costs
28
18
16
•11
12
'August 1995 dollars.
"Costs amortized at 10% for 20 years.
UV Light Disinfection Technology in
Drinking Water Application—An Overview    3-16
Final—September 1996
-------
            Chapter ^Evaluation of Ultraviolet Light Technology Costs and Comparison
           '     	      to Other Disinfection Processes
  3.3   COMPARISON OF CURRENT ULTRAVIOLET SYSTEMS COST ESTIMATES
         TO ULTRAVIOLET COSTS REPORTED IN A 1993 USEPA  DOCUMENT
  For comparison,  the document titled Very Small Systems Best Available  Technology Cost Document
  (USEPA, 1993a) provides a recent estimate of costs of using-ultraviolet technology in drinking water
  treatment.                                                                             '
                                                                    V,
  As  stated earlier, cost estimates calculated in section 3.2 are based on  two ultraviolet light doses
  40 mWs/cm2and 140 mWs/cm2.  Very Small Systems Best Available Technology Cost Document (USEPA,
  1993a) presents  models  for the calculation of ultraviolet light system  capital  and operation and
  maintenance costs.  These models were not used in the development of cost estimates for this report
  because.they were based on the 1984 WATER model, which assumes an ultraviolet light dose of 16 to
  30 mWs/cm2.  Also, when equipment and costs are being considered, it is reasonable to assume that the
  ultraviolet technology of 1984 does not include all the components of 1995, such as better control systems
  and greater lifespan.  Moreover, the 1984 WATER model is an old model that might not reflect all the
  cost variables encountered in 1995 ultraviolet systems (such as ultrasonic cleaners and automatic wipers).
 The cost estimates generated using the USEPA 1993a cost analysis are presented here to show similarities
  and differences among cost estimates.

  For flows less than or equal to 270 kgpd, the governing equation used in USEPA (1993a) to calculate
  capital costs is:                                                    -               "

:  GAP = 0.099[FLOW] +3.45            .          ,  •
  WHERE:  CAP =  Total capital costs (k$)
          "FLOW = Design flow (kgpd)
  The governing equation:
        CAP = 0.125 [FLOW] + 4.16                                      .

  is used to calculate capital costs for flows greater than  270 kgpd.  The capital costs according to this
  equation, adjusted to 1995 dollars, are presented in Exhibit 3-11 for the five EPA flow categories.
 UV Light Disinfection Technology in
 Drinking Water Application—An Overview    3-17                     Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
        	to Other Disinfection Processes

         Exhibit 3-11.  Ultraviolet Capital Cost Estimates (Source:  USEPA, 1993a)
USEPA Row
Category
1
2
3
4
5
Average Flow
(kgpd)
5.6
24
86
230
700
Design Flow
{kgpd)
24
87
270
650
1,800
Capital Cost
(k$)
5.83
12.06
30.18
85.41
229.16
Annualized: Capital Cost*
(c/kgal)
7.82
4.46
3.60
4.23
4.10
 •Costs are annualized at 10% interest for 20 years.  ,


 The WATER model for operation and maintenance costs for ultraviolet light disinfection systems assumes

 a maximum 30 mWs/cm2 dose and 0.12 hours per week for labor requirements.  The model does not

 explicitly indicate whether equipment redundancy is considered in the cost estimates.



 For flows less than or equal to 86 kgpd, the governing equation used in USEPA, 1993a to calculate
                                !• '                                   '
 operation and maintenance is:       "                      ,
     1
       OM = 17.8 [AVG]-0'427 + 209.4 [LAB]' [AVG

WHERE:   OM  = Operation and maintenance costs (c/kgal)
          AVG  = Average daily flow (kgpd)
          LAB  = Labor required (hours/week).
For flows greater than 86 kgpd, the equation used to calculate operation and maintenance cost is:


       OM = 17.8[AVG]-°-427 + 398;9 [LAB] [AVG]-1


The operation and maintenance costs calculated using this model are presented in Exhibit 3-12.


           Exhibit 3-12.  Ultraviolet Operation and Maintenance Cost Estimates
                                 (Source:  USEPA, 1993a)
USEPA Flow Category
1
2
3
4
5
Average Flow (kgpd)
5.6
24
86
230
700
Design Flow (kgpd)
24
87
270
650
1,800
O&M(c/kgaI)
13.02
5.63
2.95
1.95
1.15
•August 1995 dollars.
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-18
Final—September 1996
-------
           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                     ,   •	  to Other Disinfection Processes
 To account for varying labor estimates for different flow categories, the USEPA (1993a) O&M estimates
 are adjusted in Exhibit 3-13 using average labor requirements from three manufacturer quotes based on
 an ultraviolet light dose of 40 mWs/cm2. A graphical comparison of total production costs based on
 USEPA (1993a) labor  requirement  estimates  (see Exhibit  3-12)  and based  on manufacturer's labor
 requirement estimates (see Exhibit 3-13) is presented in Exhibit 3-14.  Exhibit  3-14 is constructed by
 adding the USEPA, 1993a annualized capital costs (see Exhibit 3-11) to USEPA, 1993a operation  and.
 maintenance costs (see Exhibit 3-12), and to the adjusted operation and maintenance costs (see Exhibit
 3-13). Exhibit 3-14 shows that adjusted labor costs have the greatest impact on the total production costs'
 of flow category one.

     Exhibit 3-13. Adjusted (USEPA, 1993a) Operation and Maintenance Costs as per
                     Manufacturers'Estimates of Labor Requirements
USEPA Flow
Category
1
2
3
- 4
5 . -
Average Flow -
(kgpd)
5.6
24
86
230
700
Design Flow
. (kgpd)
24
87
270
650
1,800
Labor Required*
(hours per week)
0.045
0.090
0.160
0.346
0.782
Adjusted O&M
Costs (c/kgal)
10.21
5.37
3.05
2.35
1.53
 •Based on average labor requirements as recommended in three manufacturer quotes. .
 Exhibit  3-15  summarizes the total cost estimates  of ultraviolet systems calculated based on labor
 requirements as reported in Very Small Systems  Best Available Technology Cost Document (USEPA,
 1993a), and based on adjusted operation and maintenance costs.

 For cost verification purposes, graphical comparisons of the costs developed by SAIC under this task for
 ultraviolet systems delivering a 40 mWs/cm2 dose and a 140 40 mWs/cm2 dose and costs calculated based
 on the methodology provided in USEPA (1993a).  Graphical presentation for capital costs are presented
 in,Exhibit 3-16.  As can be seen from Exhibit 3-16,  for How category 1 (design flow 24 Kgpd), capital
 costs for ultraviolet systems delivering doses ranging from 16-30 mWs/cm2 to 140 mWs/cm2 are very
 close.

For flow categories 2 and 3, capital costs for ultraviolet systems delivering an ultraviolet light dose of less
than 40 mWs/cm2 are almost identical.  The capital costs of 140 mWs/cm2 ultraviolet treatment system
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-19
Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                             to Other Disinfection Processes
  Exhibit 3-14. Comparison of Total Production Costs with Varying Labor Requirements
        25
        20  -
    *
    1
     8
        10  -
         5  -
        0
                 0.024
0.087       0.27        0.65
    Design Flow (MGD)
      1.8
             Total Production Costs: USEPA (1993a) Estimate of Labor Requirements

             Total Production Costs: Manufacturers' Estimates of Labor Requirements
UV Light Disinfection Technology in
Drinking Water Application—An Overview
          3-20
Final—September 1996
-------
           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
           	' •           to Other Disinfection Processes
              Exhibit 3-15.  Ultraviolet Cost Estimates (Source:  USEPA, 1993a)
USEPA
Flow
Category
1


4

Average
Flow
(kgpd)
5.6
r 24
86
230
700
Design
Flow
(kgpd)
24
87
270
650
1,800
Capital
Cost (k$)
5.83
12.06
30.18
85.41
229.16
Annualized
Capital Cost*
(c/kgal)
7.82
4.46
3.60
4.23
4.10
O&M**
(c/kgal)
13.02
5.63
2.95
1.95
1.15
Total
Production
Costs
(c/kgal)
21
10
7
6
5
Total Production
Costs with
Adjusted O&M
Costs (c/kgal) •
18
10
•7
7
6
 •Capital cost amortized at 10% interest over 20 years.                      '      .
 "Based on USEPA (1993a) tebor requirements of 0.12 hours per week, for all flow categories.
                                         '               '   '  •           •            V
 is the highest for flow categories 2 through 5.  For flow categories 4 and 5, current capital cost estimates
 for 40 mWs/cm2 ultraviolet systems are lower than capital cost estimates calculated based on the USEPA,
 1993a water cost model for a 16-30 mWs/cm2 ultraviolet treatment system.  Graphical presentations of
 operation and maintenance costs for 16-30 mWs/cm2,40 mWs/cm2,and 140 mWs/cm2 ultraviolet treatment
 systems are presented in Exhibit 3-17. As can be seen from Exhibit 3-17, operation and maintenance cost
 estimates for a 140 mWs/cm2 ultraviolet treatment system are higher than the operation and maintenance
 cost estimates for a 40 mWs/cm2 ultraviolet treatment system for flow categories 1 through 5.  Operation
 and maintenance cost estimates for a 140 mWs/cm2 ultraviolet treatment system are higher than  the
 operation and maintenance costs estimates developed  using USEPA,  1993c methodology for flow
 categories 2 through 5.               ,              -

 Graphical comparisons of total production cost estimates  developed by SAIC under'this  task for 40
,mWs/cm2 and 140 mWs/cm2 ultraviolet treatment systems and total production cost estimates for 16-30
 mWs/cm2 ultraviolet treatment systems developed using USEPA, 1993a methodology are presented in
 Exhibit 3-18.                                     ,

 As can be seen from Exhibit 3-18, the costs estimated by USEPA (1993a) are close  to those estimated
 using manufacturer's quotes for the 40 mWs/cm2 dosage.  Overall, however, costs for ultraviolet systems
 delivering 40  mWs/cm2  dosage are consistently approximately two cents per thousand gallons less
expensive than the USEPA (1993a) estimates for total production costs for ultraviolet systems delivering
 16to  30 mWs/cm2 dosage.
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-21
                                                                      Final—September 1996
-------
         Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                              to Other Disinfection Processes
           Exhibit 3-16. Comparison of Capital Costs of Ultraviolet Treatment
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-22
.Final—September 1996
-------
          Chapter 3-Evaluation of Ultraviolet Light Technology Costs and Comparison
         „	/to Other Disinfection Processes
  Exhibit 3-17. Comparison of Operation and Maintenance Costs of Ultraviolet Treatment
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-23
Final—September 1996
-------
         Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison

                             to Other Disinfection Processes
       Exhibit 3-18.  Comparison of Total Production Costs of Ultraviolet Treatment
                                                              o

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o
-------
           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
       "-   .      .  ' '	   to Other Disinfection Processes

 3.4   ULTRAVIOLET LIGHT SYSTEM COSTS COMPARED TO CHLORINATION
        AND OZONATION DISINFECTION TECHNOLOGIES

 In this section, the current total cost for ultraviolet treatment is compared to that of chlorination and

 ozonation. Chlorination and ozonation costs reported here are obtained from USEPA (1993a), calculated
 in August 1995 dollars.


 3.4.1   Ozonation Costs

 The following formulas apply to small and large decentralized systems employing primary treatment
 through ozonation (USEPA,  1993a):


 CAPITAL COSTS:          :

 For flows less than or equal to 270 kgpd, the equation used to calculate capital costs  for an ozonation
 system that can deliver an ozone  dose of 1 mg/L is:
                 |0.272
 CAP1 = 24.2[DES]

 WHERE:  CAP1 =.Total capital cost, 1 mg/L ozone dose (k$)
          DBS = Total design .flow (kgpd)

 For flows greater than 270 kgpd, the equation used to calculate capital costs for an ozonation system that
 can deliver an ozone dose of 1  mg/L is:

 CAP1 = 28.0PES]0-269

 WHERE: CAP1 = Total capital cost,  1 mg/L ozone, dose (k$) •
         DBS = Total design flow (kgpd)     ,


 These ozonation costs are based on a dose of 1 mg/L and an assumed contact time of 10 minutes.  This

 dose is  a "low demand" dose with an assumed residual of Q.I mg/L.  Ozone treatment at this  dose

 provides the lowest cost estimate for ah ozone drinking water disinfection system.


 O&M COSTS:                                                      ,

 For flows less than or equaTto 86 kgpd, the equation used to calculate operation and maintenance costs
 of an ozone system delivering 1 mg/L is:
OM1 = 24.8[AVG]^-486 + 209.8[LAB][AVG]
UV Light Disinfection Technology in
Drinking Water Application—An Overview    3-25                     Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
 	to Other Disinfection Processes	
 WHERE: OM1 = O&M costs, 1 mg/L ozone dose, (c/kgal)
          AVG = Average daily flow (kgp'd)                       ,
          LAB = Available labor for O&M (hrs/week)
 For flows greater than 86 kgpd, the equation used to calculate operation and maintenance costs is:
 OM1 = 24.8[AVG]-°-486 + 398.9[LAB][AVG3-'
 WHERE: OM1 = O&M costs, 1 mg/L ozone dose, (c/kgal)
          AVG = Average daily flow (kgpd)
          LAB = Available labor for O&M (hrs/week)

 According to USEPA (1993a), labor requirements are assumed to be 7 hours per week. The cost estimates
 for the ^installation of such an ozone facility include an off-gas destruction unit, ozone gas detector and
 alarm, and building with ventilation to house the system  (USEPA, 1993a).

 Exhibit 3-19 is a tabular representation of the calculated costs of ozone treatment from USEPA (1993a).

                       Exhibit 3-19. Small System Ozonation Costs
                                 (Source:  USEPA, 1993a)
USEPA Row
Category
1
2
3
4
5
Average
•Flow (kgpd)
5.6 .
24
86
230
700
Total Capital
(k$)
57.44
81.54
110.95
159.39
210.29
Total Capital
(0/kgal)
77.02
30.16
13.22
7.92
3.76
Total O&M
(c/kgal)
273.99
66.48
19.92
13.90
5.02
Total Production
Cost (c/kgal)
351
97
33
22-
9
'August 1995 dollars.
"Cost amortized at 10% for 20 years.
3.4.2  Chlorination Costs
Chlorination cost estimates are based on a 5 mg/L dose with an assumed residual concentration of at least
0.5 mg/L and a labor requirement of seven to ten hours per week. This extrapolates (linear extrapolation)
to 7, 7.1, 7.4,  8.1, and 10 hours per week for flow categories 1 through 5, respectively.  While chlorine
treatment dose could range from 1 to 10 mg/L, the 5 mg/L dose also reflects a "medium demand" dose
and provides a reasonable cost estimate for a Chlorination process (sodium hypochlorite feed system).  The
cost estimates based on the USEPA (1993a) document for the installation of a Chlorination facility include
a metering pump, a mixer and storage tank, and various pipes and valves.
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-26
Final—September 1996
-------
             Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
   •  •   -                    	to Other Disinfection Processes              ,
    CAPITAL COSTS
   .For flows less than or equal to 270 kgpd, the capital cost!;are assumed to be:
  .  CAP = 4.7 •                          '.    .   •     .•-.'"        •'•       '   '.-   .
    For flows greater than 270 kgpd, the capital costs are assumed to be:
    CAP = 6.9                .                          '  '.                   ,
    WHERE: CAP = Total capital cost (k$)

    It is important to note that the capital costs do.not vary with flow due to the wide range of pumping rates
•   achievable by similarly priced pumps (USEPA, 1993a)

   O&M COSTS:         .
  • For flows less than or equal to 86 kgpd, the governing equation for operation and maintenance costs is:
   OM = 66.0CAVG]-1 + 0.67[C1] + 209.4[LAB][AVG]-1
   WHERE:  OM=t O&M costs (c/kgal)
             AVG = Average daily flow (kgpd)                           ,
             Cl = Chlorine dosage (mg/L)
            LAB = Available labor for O&M (hrs/week)  '
 .  For flows greater than 86 kgpd, the governing equation for operation and maintenance costs is:
   OM = 66.0[AVGr] + 0.67[C1] + 398.9[LAB][AVG]-1
   WHERE: OM = O&M costs (c/kgal)
            AVG = Average daily flow (kgpd)
            Cl = Chlorine dosage (mg/L)
            LAB = Available labor for O&M (hrs/week)        ,                '

   Exhibit 3-20 presents the calculated costs for chlorination based on the equations provided in the USEPA
   (1993a) document.       •                                                        '

   Exhibit 3-21 is a tabular presentation of current ultraviolet light system costs developed for ultraviolet
   light doses of 40 mWs/cm2 and 140 mWs/cm2 compared to ozonation and chlorination. Exhibit 3-22 is
   a graphical presentation of current ultraviolet light costs for an" ultraviolet dose of 40 mWs/cm2 developed
   under this work assignment compared to costs of ozonation and chlorination. Exhibit 3-23 is a graphical
   presentation of current ultraviolet light system costs for an ultraviolet light dose of 140 mWs/cm2
   developed under this task compared to costs of ozonation and chlorination.
  UV Light Disinfection Technology in
  Drinking Water Application—An Overview     3-27                      Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
        	to Other Disinfection Processes	/	
         Exhibit 3-20.  Small System Chlorination Costs (Source:  USEPA, 1993a)
USEPA Flow
Category
1
2
3
4
5
Average
Flow
(kgpd)
5.6
24
86
230
700
Total
Capital
(k$)
4.70
4.70
4.70
6.90
6.90
Total
Capital
(c/kgal)
6.30
1.74
0.56
0.34
0.12
Labor
Requirements
(hours/week)
7
7.1
7.4
8.1
10
Total O&M
(c/kgal)
276.89
68.05
22.14
17.68.
9.14
Total
Production Cost
(c/kgal)
283
70
23
18
9
*Costs amortized at 10% interest for 20 years.
"August 1995 dollars.
 Exhibit 3-21. Ultraviolet Light System Costs for USEPA Flow Categories 1-5 Compared
              to Chlorination and Ozonation in Cents per Thousand Gallons*
USEPA Row
Category
1
2
3
4
5
Design Flow
MGD
0.024
0.087
0.27
0.65
1.8
Ultraviolet
Dose
40 mWs/cm2
19
8
5
5
4
Chlorination
Dose 5 mg/L
283
70
23
18
9
Ozonation
Dose 1 mg/L
351
97
33
22
9
Ultraviolet
Dose
140 mWs/cm2
28
18
16
11
12 '
'August 1995 dollars..                        '  ,

Based on the above, it is clear that ultraviolet light technology is an economically viable and feasible
technology, particularly for small water systems that lack highly paid qualified operators. Moreover, it
is anticipated that, as  more ultraviolet light technology is developed, the capital and operation and
maintenance costs associated with ultraviolet treatment will decrease, making this technology  more
competitive.                                     '                 .
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-28
Final—September 1996
-------
         Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
   	'  •     	  to Other Disinfection Processes                .

    Exhibit 3-22. Ultraviolet [40 mWs/cm2], Chlorination, and Ozonation Total Costs:
                             USEPA Flow Categories 1-5
       400
      300  -
   ^

    I
200  -
      100  -
         0
                 0.024       0.087        0.27        0.65
                                  Design Flow (MGD)
                                                              1.8
          Ozonation Dose: 1 mg/l           §• Ghlorination Dose: 5 mg/L

          UV Radiation Dose: 40 mWs/sq cm
UV Light Disinfection Technology in
Drinking Water Application—An Overview    3-29
                                                        Final—September 1996
-------
         Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                            to Other Disinfection Processes
   Exhibit 3-23. Ultraviolet [140 mWs/cm2], Chlorination, and Ozonation Total Costs:
                            USEPA Flow Categories 1-5
       400
       300  -
   ff

   I
    8
200  -
      100  -
         0
                 0.024       0.087        0.27        0.65
                                 Design Flow (MOD)
                                                              1.8
         Ozonation Dose: 1 mg/1

         UV Radiation Dose: 140 mWs/sq cm
                                       Chlorination Dose: 5 mg/1
UV Light Disinfection Technology in
Drinking Water Application—An Overview    3-30
                                                        Final—September 1996
-------
          Chapter 3— Evaluation of Ultraviolet Light Technology Costs and Comparison
    .   _ __ _ to Other Disinfection Processes  .
 3.5    COST OF ULTRAVIOLET DISINFECTION WITH SECONDARY TREATMENT
        THROUGH  CHLORINATION
 Because a residual may be desired in the distribution system, ultraviolet disinfection may be supplemented
 by chlorination as a secondary treatment process. This typically involves the use of sodium hypochlorite
 or calcium hypochlorite. A chlorine concentration of 1 mg/L can "be assumed.  Such a concentration is
 sufficient to control microbial growth in the distribution system.

 3.5.1   Cost of Secondary Treatment
  -                         "                 .               '  -        ,             •        i
 For our purposes, sodium hypochlorite will  be used, which, according  to USEPA (1993a),  costs
 approximately $190 per ton of chemical.  The amount of chemical to be used per day can be calculated
 by dividing the amount of chlorine required per day by the percentage of -available chlorine in the
 chemical to be purchased.  One can assume that sodium hypochlorite (NaOCl) or calcium hypochlorite
 [Ca(ClO)2] is at least 65 percent available chlorine (practical grade; theoretical available chlorine in NaOCl
 is 95.4% and in Ca(ClO)2 is 99.2%). The use of the dose-dependent equation for chlorine disinfection
 costs presented iri USEPA (1993a) as shown in section 3.4.2 is appropriate here, assuming a chlorine dose
 of 1 mg/L. This dosage is high enough to leave a residual and ensure thorough disinfection while low
 enough to minimize costs.

 Although it is not necessary to determine the amount of chlorine required to satisfy a 1 mg/L dosage
 requirement, doing so may  shed some light on the size of storage tank needed and the amount of labor.
 required to mix the chemicals and fill the storage tank. The following equations may be used to determine
 chlorine arid stock solution  requirements:                       -

       • Pounds per day chlorine required =.

 .-:'-    Average  Flow f-^-1 x dose fail x     l ^    x  — *i x '
                                     '
                                                             —
                           dayj      ' (I )    1000000 mg    0.45kg     gal

       • Assume 65% available chlorine in sodium hypochlorite and a 5% stock solution
       • Gallons per day of stock solution requires =

                                     Qbs/day chlorine)
                            (5% Hypochlorite Strength) x 8.3   £
                                                           gal

The resulting stock solution requirements are presented in Exhibit 3-24.
UV Light Disinfection Technology in
Drinking Water Application— An Overview    3-31                      Final— September 1996
-------
           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                                to Other Disinfection Processes
     Exhibit 3-24. Amount of Chlorine Stock Solution Required Per Day (1 mg/L Dose)
USEPA How
Category
1
2
3
4
5
Average Daily Flow
(kgpd)
5.6
2.4
86.0
230.0
. 700.0
Gallons/Day Stock
Solution Required - .
0.12
0.48
1.71
4.60
14.00
 Because these are relatively small amounts of required stock solution, a standard 150-gallon tank would
 be too large. If a 150-gallon stock is prepared for use, the chlorine would evaporate out of the solution
 before the solution is completely used.  A smaller storage tank that would necessitate refilling with stock
 solution would be more suitable.  To prepare fresh stocks, a 2-hour labor requirements is assumed every
 4 days for flow categories one, two, and three (35 hrs/week). A 2-hour labor requirement is assumed for
 flow categories four and five with chlorine stock solution prepared every other day (7 hrs/week).
                                                                                i
 The costs associated  with secondary  treatment are presented  in tabular .form in Exhibit 3-25 and
 graphically in Exhibit 3-26. Some non-community water systems may find the 1 mg/L dosage of chlorine
 suitable for complete water treatment, in which case these  costs could be adapted to estimate primary
 disinfection through chlorination.  In  a 20-month pilot study, 0.05 mg/L of free chlorine after ultraviolet
 treatment was found to be sufficient to suppress biofilm formation (Lund and Ormerod, 1995).  In  small
 systems, a residual free chlorine levels of 0.2 mg/L are considered to be sufficient to protect water supplies
 (Huck, 1989).  It is of interest to note that the overall cost of treatment with 1 mg/L chlorine differs from
 treatment with 5 mg/L chlorine by only a few cents per thousand gallons.

 Exhibit 3-25. Total Production Costs of Secondary Treatment Through 1 mg/L Chlorine
USEPA
Flow
Category
1
2
3
4
5
Average
Row
(kgpd)
5.6
24
86
230
700
Design
Row
{kgpd)
24
87
270
650
1800
Capital
Cost (k$)
4.70
4.70
4.70
6.90
6.90
Amortized
Capital Cost
(c/kgal)
6.30
1.74
0.56
0.34
0.12
Labor
Requirement
(hrs/week)
3.5
3.5
3.5
7.0'
7.0
O&M
Costs
(c/kgal)
143.33
33.96
9.96
13.10
4.75
Total
Production
Costs (c/kgal)
150
36
11
13
5 .
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-32
Final—September 1996
-------
           Chapter 3-Evaluation of Ultraviolet Light Technology Costs and Comparison
                                to Other Disinfection Processes
  o>
  0)
  o
  Q
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  O
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 O
 U)
 I

 o
 '•5
 w
 5
 •5
 •§
 o
 (6
 «
 4»
 s
 x
 UJ
t/1/ L/g/jf Disinfection Technology in
Drinking Water Application—An Overview
3-33
                                                                    Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
 	to Other Disinfection Processes
 3.5.2  Total Production Costs for Ultraviolet Disinfection with Chiorination
 Total production costs of primary disinfection through ultraviolet treatment and secondary disinfection
 through chlorination are presented in Exhibit 3-27.  These costs were found by simply adding the costs
 of ultraviolet treatment at dosages of 40 and 140 mWs/cm2 to the costs of chlorination at a dosage of 1
 mg/L. Total production costs for ultraviolet treatment and secondary disinfection through chlorination are
 presented graphically in Exhibit 3-28.
            Exhibit 3-27. Total Production Costs of Ultraviolet Treatment with
                                  Secondary Disinfection
USEPA
Row
Category
1
2
3
4
5
Average
Flow
(kgpd)
5.5
24
86
230
700
Design
Flow
(kgpd)
24
87
270
650
1800
Total Production Costs (c/kgal)
40 mWs/cm2
UV Treatment
19
8
5
•• 5
. 4
140 mWs/cm2
UV Treatment
28 . .
18
16
11
12
40 mWs/cm51 UV
Treatment with
1 mg/L Chorine
169
44
16
18
9
140 mWs/cm2 UV
Treatment with
1 mg/L Chorine
178
54
27
24
17
3.5.3  Comparison to Other Treatment Techniques
Exhibits 3-29 and 3-30 are graphical presentations of the total costs of ozonation,  chlorination, and
ultraviolet disinfection with 1 mg/L chlorine secondary treatment, at ultraviolet doses of 40 mWs/cm2 and
140 mWs/cm2, respectively. Exhibit 3-31 is a tabular presentation of the costs of ultraviolet light system
with chlorination compared to ozonation and chlorination.      '

3.6    ULTRAVIOLET LIGHT SYSTEM COST ESTIMATES FROM OTHER
       SOURCES
                                                                            E
The Canadian pilot plant study cited earlier (Zukovs et al., 1986) compared the costs of ultraviolet light
application in combined sewer overflows (CSOs) to those of chlorination/dechlorination systems required
to achieve similar bacterial kill.  The estimated capital costs for ultraviolet light systems used on low-
quality CSOs were consistently higher than those for chlorination/dechlorination systems for flow rates
between 5,000 and 500,000 m3/d (1.3 MOD - 132 MOD). However, the operation and maintenance costs
for both systems were within the same order of magnitude (Exhibit 3-32).
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-34
, Final—September 1996
-------
           Chapter 3-Evaluation of Ultraviolet Light Technology Costs and Compari
                                to Other Disinfection Processes
son
      Exhibit 3-28. Total Production Costs for Ultraviolet Disinfection with Chlorination
                                           noijonpoo&
UV Light Disinfection Technology in
Drinking Water Application—An Overview    ,3-35
                                                                  Final—September 1996
-------
         Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                            to Other Disinfection Processes
      Exhibit 3-29. Total Costs: Ozonation, Chiorination, and Ultraviolet Radiation
                       (40 mWs/cm2) with Secondary Treatment
       400
      300  -
   k>
   •^

   1
      100  -
         0
                 0.024      0.087       0.27        0.65
                                 Design Flow (MOD)
                             1.8
       Ozonation Dose: 1 mg/L             Hi Chiorination Dose: 5 mg/L

       UV Radiation Dose: 40 mWs/sq cm plus 1 mg/L chlorine
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-36
Final—September 1996
-------
           Chapter 3-Evaluation of Ultraviolet Light Technology Costs and Comparison
             '•	_	  to Other Disinfection Processes

        Exhibit 3-30. Total CoSts  ozonation, Chlorination, and Ultraviolet Radiation
                        (140 mWs/cm2) with Secondary Treatment
          0
                  0.024      0.087       0.27        0.65
                                  Design Flow (MOD)
                        1.8
        Ozonation Dose: 1 mg/L
I Chlorination Dose: 5 mg/L
        UV Radiation Dose: 140 mWs/sq cm plus 1 mg/L chlorine
:UV Light Disinfection Technology in
Drinking Water Application—An Overview    3-37
                                                               Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                                to Other Disinfection Processes
 Exhibit 3-31. Total Production Costs of Ultraviolet Treatment with Secondary Treatment
                          Compared to Chlorination and Ozonation
USEPA Row
Category
1
2
3
4
.5
Design
Row
(MGD)
0.024
0.087
0.27
0.65
1.8
Average
Flow
(kgpd)
5.6
24
86
' 230
700
Total Production Costs (Cents per Thousand Gallons)1
Chlorination
Dose 5 mg/L
280
70
20
20
;10
Ultraviolet
Dose 40
mWs/cm2
with 1 mg/L
Chlorination
170
40
20
20
10
• Ozonation
Dose 1 mg/L
350
100
30
20
10
Ultraviolet
Dose 140
mWs/cm2
with 1 mg/L
Chlorination
180
50
30
, 20
20
 'Rgures are rounded to nearest ten.

    Exhibit 3-32. Estimated Capital and Operating Costs for Ultraviolet Irradiation and
                      Chlorination/Dechlorination (Zukovs et al., 1986)'
Flowrate MGD
1.3
13.2
132
UV Irradiation
Capital Cost ($1985
Canadian)
245,200
2,208,180
21,801,000
O&M Cost ($1985
Canadian/Year)
.18,110
78,925
672,700
Chlorination/Dechlorination
Capital Cost ($1985
Canadian)
50,560
84,120
380,305
O&M Cost ($1985
Canadian/Year)
16,790
60,700
496,000
In an actual case study of costs associated with ultraviolet disinfection in the Zevenbergen drinking water
treatment plant (the Netherlands), the annual costs associated with a design flow of 450 nrVhr (1,981 gpm)
with an actual production of 2.5 x 10s m3/yr (1.8 MGD) using'two different ultraviolet light disinfection
devices were $0.0054/m3 and $0.0057/m3 (2.04 c/kgal and 2.16 c/kgal) (see Exhibit 3-33). The annualized
cost of ultraviolet light disinfection reported in the text of the article by Kruithof  et al; (1992) at
$1/2,000 m3 (0.1893 c/kgal) is  one  order of magnitude less than, the figures  shown in Exhibit 3-33.
Evidently, this low cost figure of 0.1893 c/kgal. is the result of a mathematical error on the part of the
authors.

As can be seen from Exhibit 3-33, the high cost estimates of ultraviolet light water disinfection systems
in the United States (see Exhibits 3-4, 3-9, and 3-10) compared to the costs of ultraviolet disinfection
systems in the Netherlands  as reported in Kruithof et al.  (1992) has to do primarily with capital costs
($73,000 to $80,000 per system in the Netherlands compared  to $91,200  to $171,100 per system for the
same flow category as a 40  mWs/cm2 ultraviolet dose in the United States) and energy  costs (5.2 to 5.5
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-38
Final—September 1996
-------
           Chapter-3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                                 to Other Disinfection Processes
                   ~  Exhibit 3-33.  Ultraviolet Light Treatment System
Model Berson ,
3X2HGS-200
Depreciation
$73,000; annuity 15 years, 7%
Energy Consumption
61,325 kWhr for UV radiation
7,700 kWhr for headless
Replacements
6 UV-bymers
2 Quartz tubes
Total Costs
Costs: perm3
per kgal
$8,000
$3,200
$420
$1,350
$270
$13,240
$0.0054
$0.0204
Model Katadyn
2XGFM6
Depreciation
$80,000; annuity 15 years, 7%
Energy Consumption
1 0,946 kWhr for U V radiation
20,989 kWhr for headless
Replacements
20UV-bumers
4 Quartz tubes
Total Costs
Costs: per m3
per kgal
$8,700
$600
$1,1500
$2,900
• $1,000
$14,350
$0.0057
$0.0216
  cents per kWhr in the Netherlands compared to 8.6 cents per kWhr in the United States). The average
  annualized cost of ultraviolet disinfection systems in the Netherlands is about 2 c/Kgal for a flow of 1.8
  MOD. The average annualized cost estimated for comparable systems in the United States is 4.4 c/Kgal.

  3.7   SMALL NON^COMMUNITY WATER SYSTEMS FLOW REQUIREMENTS AND
        COST IMPLICATIONS
  Ultraviolet disinfection cost estimates for USEPA flow category 1 are estimated at $1,700 per year for an
  ultraviolet light system delivering 40 mWs/cm2, and at $2,500 per year for an ultraviolet light system
  delivering 140 mWs/cm2. As stated earlier, USEPA flow category 1 has a design flow of 24,000 gallons
 per day and an average flow production of 5,600 gallons per day. Such  design and average flow
  assumptions are believed to be sufficient to satisfy me drinking water requirements of a population of 25
/to 100 persons  served by a Community Water Supply (CWS) system.  These flows and population
 assumptions imply a minimum average water production of 56 gallons per person per day (based on a
 population of 100).

 While such assumptions are useful to USEPA in its evaluation of costs projected for community  water
 supply systems, it is  unlikely that they will apply to many Non-Community Water  (NCW)  systems
 according to some sources.  The drinking water requirements for water use in many NCW systems are
 expected to be much lower than those required in small CWS systems. The information obtained from
 USEPA's Safe Drinking Water Information System (SDWIS) shows that approximately 91,000 ground
 water NCW systems service a population of about 12 million.  Exhibit 3-34 presents  SDWIS data on
 ground water NCW systems facility type for two population ranges.
 UV Light Disinfection Technology in
 Drinking Water Application—An Overview     3-39
Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
      	to Other Disinfection Processes

       Exhibit 3-34. Ground Water NCW Systems Serving Two Population Ranges
Facility
(SDWIS Description)
Day Care Center
Dispenser
Homeowners Association
Hotel/Motel
Highway Rest Area
Industrial/Agricultural
Interstate Carrier
Institution
Medical Facility
Mobile Home Park
Mobile Home Park, Principal
Residence
Municipality
Other Area
Other Non-Transient Area
Other Residential Area
Other Transient Area
Recreation Area
Residential Area
Retail Employees
Restaurant
School
Sanitary Improvement District
Summer Camp
Secondary Residences
Service Station
Subdivision
Water Bottler
Wholesaler (Sells Water)
TOTAL
Number of Systems Serving a
Population of 25 to 50
Persons
280
-
-
1864
293
2059
11
437
122
346
.
,
4,840
946
314
10,450
7,609.
716
•
7,649
921
-
895
-
1,376
- •
-
42
41,170
Number of Systems Serving a
Population Greater Than 3,300
Persons
- ' •
, -

2
37
19
2
3
4
. . .
- '
-
18 . •.
8
-
22
68
6
-
10
14
-
3
• -
• 1
-
-
-
217
 ' Based on 9/25/96 SDWIS data for ground water NCW systems with treatment equipment '
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-40
Final—September 1996
-------
           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
  	 .  .;	        to Other Disinfection Processes
  Exhibit 3-35 provides a list of average water use per person at typical NCW facilities. If the USEPA flow
  rate for category 1 (i.e., 5,600 gpd) were used in this context (for small NCW systems), then NCW
  systems servicing carry-out restaurants or airports, could conceivably be providing enough water for 1,865
  persons and 1,600 persons, respectively, which is far greater than the number of people served by that
  flow category (25 - 100).                   •                   -   .            •
        Exhibit 3-35.  Typical Rates of Water Use in Non-Community Water Systems*
Facility
Airport 	 —
Amusement Parks: - : 	 	
^H? wf ter enterta'inment, food facilities, flush toilets, and shower facilities
Without water entertainment, but with food facilities and flush toilets

Camps:
Construction •
Day with no meal served
Luxury
Resorts . -
Tourist with central bath' and toilet facilities
Cottages . : . r. —
Country Club , "- 	 '- 	 	 ~
Day Care Center : "
Department Store r • < 	
Factory •.'••• : 	
Highway Rest Area 	 	
Highway Rest Area with Minimarket : ~~~
Hospital — —
Lodging House/Tourist House
Medical Facility • 	
Motel 	
Office - . 	
Parks: 	 —•
Overnight with Flush Toilets •
Trailers
Picnic Areas 	
Restaurant: - : —
Conventional
Carry-Out
Bar and Cocktail Lounqe • ,
Schools:' "~- :
With cafeteria, gymnasium, and showers
With cafeteria, but no gymnasium or showers
Without cafeteria, gymnasium, or showers
Side Road Store
Shopping Center ;
Theater : 	
Worship Places: • :
With day care facility, and no permanent residents
With abolition facilities, day care facility, and no permanent residents
With less than 25 permanent residents and day care facility '
With less than 25 permanent residents and no day care facility
Average Water Use
gal/person/day
3.5
40
10
10
50
15
100
50
35
50
40
4
10

10

100
40
10
40
15
25
40
10
9
3
.15
25
• 20
15
5
o
4
2
5
12
10
'Based in part on best professional judgment, Metcalf and Eddy, 1991 and Corbitt, 1990.
UV Light Disinfection Technology in
Drinking Water Application—An Overview
3-41-
                                                                      Final—September 1996
-------
          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
                                to Other. Disinfection Processes
 •"""—^-^mm•••WMMWVMi^^_«M.^..'ma^^—m«H^MMIM^^^^^^-VM.
 Water use rates shown in Exhibit 3-35 were compiled in part from Metcalf and Eddy, 1991, and Corbitt,
 1990, and based in part on best professional judgment. Exhibit 3-35 suggests a need for developing new
 flow methodologies for USEPA treatment cost analyses addressirig  various types of NCW systems.

 3.8    CONCLUSIONS
 Based on the cost estimates presented in this chapter, ultraviolet light technology is an economically viable
 and feasible technology, particularly for small water systems. The costs of using ultraviolet light alone
 (at a dose of 140 mWs/cm2 or less) to disinfect ground water are far lower than using ozone and more
 economical than chlorination for flow categories 1 through 4 (design flow 0.024 to 0.65 MGD). The costs
 of using ultraviolet light alone at a dose of 40 mWs/cm2 are far lower than using ozone or chlorine
 (hypochlorites) for primary disinfection for flow categories 1 through 5 (design flow 0.024 to 1.8 MGD).

 The costs of chlorination, used in this chapter for comparison purposes, do not include the additional costs
 incurred to cover the new requirements under Article 80 of the Uniform Fire Code (UFC) of 1991. These
 new requirements include additional equipment to handle accidental release of chlorine gas or chlorine
 dioxide and its onsite production components (where used) and emergency power sufficient to operate
 chemical scrubbing.equipment. The costs associated  with these requirements can represent as much as
 25 percent of  the total capital costs for small systems using chlorine  gas or chlorine  dioxide for
 disinfection (WERE, 1995).

 The costs of using  ultraviolet light (at a dose of 140 mWs/cm2 or less) for primary disinfection in
 combination with chlorination for secondary disinfection to disinfect ground water are lower than the costs
 of ozonation and chlorination for flow categories 1 and 2.  Ultraviolet disinfection costs, at a dose of 140
mWs/cm2, plus the costs of chlorination for residual disinfection, are comparable to ozonation costs for
USEPA flow categories 3 and 4 and higher than the costs of ozonation and chlorination alone for USEPA
flow category 5.  Ultraviolet light disinfection costs at 40 mWs/cm2 plus the costs of chlorination for
residual disinfection are comparable to the costs of chlorination for USEPA flow categories 3 through 5
and are comparable to the costs of ozonation for USEPA flow categories 4 and 5 and lower than the costs
of ozonation for USEPA flow category 3. Also, it is concluded that  rationale are available to justify use
of an alternate flow regime and, therefore, alternate cost estimates that would better fit in the analysis of
non-community type water systems.                                                 v
UV Light Disinfection Technology in
Drinking Water Application—An Overview     3-42                       Final—September 1996
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           Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
    -   •'	• '•  -	to Other Disinfection Processes

  3.9    REFERENCES


  ANSI/NSF (1991).  American National Standards Instimtl/Natibnaf Sanitation Foundation International
  Standard Number 55, Ultraviolet Microbiological Water Treatment Systems.

  Chen, C.L.  and Kuo, J.F.  (1992).   UV Inactivation of Bacteria and Viruses in Tertiary Effluent
  Presentation to the DHS UV Disinfection Committee on Research at the County Sanitation Districts of
  Los Angeles County.  (As cited in WERF, 1995)                  .

  CH2M HILL (1992).  UV Disinfection Pilot Study - Rapid Infiltration/Extraction (RIX) Demonstration
  Project.  Prepared for Santa Ana Watershed Project Authority, City of San Bernardino, City  of Colton
  (As cited in WERF, 1995)                     -.-'..

  Corbitt, R.A. (1990). Standard Handbook of Environmental Engineering.  McGraw-Hill, Inc.

  DPRA (1993). Small Water System By-products Treatment and Disposal Cost Document.  Draft Final
 Prepared for USEPA OGWDW.

 ENR (1995). "Construction Cost Index History 1907-1995:"  Engineering News Record, March 27,1995.
 p. 80.                           '                               .'-.'.,

 Harris, G.D., et al. (1986). "UV Inactivation of Selected Bacteria and Viruses with Photoreactivation of
 the Bacteria." „ Water Resources, Vol. 21, pp. 687-692.

 Huck, P. (1989).  "Reduction in Organic Levels and Disinfection Demand by Slow Sand Filtration in
 Western Europe." Drinking Water Treatment Small.System Alternatives. Toft, T.obin, and Sharp, editors
 New York:  Pergamon Press, pp. 77-94.  .                           "

 Kraithof, J.C.,  van der Leer, R.C.,  and Hijnen, W.A.M.  (1992).  "Practical Experiences With UV
 Disinfection in  the Netherlands." Aqua, Vol. 41,"No! 2, pp. 88-94.
                        A                    .                     •         ,           ••*.•  =
 Lund,  V. and Orrrierod, K. (1995).' The Influence of Disinfection Processes on Biofilm Formation in
 Water Distribution Systems.  Water Research,  Vol. 29, No. 4, pp. 1013-1021.

 Metcalf and Eddy (1991).  Wastewater Engineering:  Treatment; Disposal and Reuse. 3rd Ed. McGraw-
 Hill, Inc.

 NWRI (1993). UV Disinfection Guidelines for Wastewater Reclamation in California and UV Disinfection
 Research Needs Identification.  National Water Research Institute, pp. 1-28.

 PPPI (1995).  "Survey of Current Business." Producer Prices and Price Indexes, Vol. 75, -No. 8. U.S.
 Bureau of Labor Statistics, U.S. Department of Commerce.                                  .

USEPA (1983). Microorganism Removal in Small Systems. Office of Drinking Water  EPA 570/9-83-
012.         .                          ,

USEPA (198,9).  Technologies for Upgrading Existing or Designing New Drinking Water Treatment
Facilities. .Office of Drinking Water.  EPA 625/4-89/023.
UV Light Disinfection Technology in
Drinking Water Application—An Overview    3-43                      Final—September 1996
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          Chapter 3—Evaluation of Ultraviolet Light Technology Costs and Comparison
 	to Other Disinfection Processes	

 USEPA  (1992).  UV Disinfection Technology Assessment.  Office of Wastewater Enforcement and
 Compliance.  EPA 832-K-92-004.

 USEPA  (1993a).  Very Small Systems Best Available Technology Cost Document.  Drinking Water
 Technology Branch, OGWDW, USEPA. Malcolm Pirnie, Inc.

 USEPA (1993b). Technologies and Costs for Ground Water Disinfection. Drinking Water Technology,
 Branch, OGWDW, USEPA. Draft Document, Malcolm Pirnie, Inc.

 USEPA (1993c). Technical and Economic Capacity of States and Public Water Systems to Implement
 Drinking Water Regulations—Report to Congress.

 WERF (1995).  Comparison of UV Irradiation to Chlorination:  Guidance for Achieving' Optimal
 Performance.  Water Environment Research Foundation.

 WWEMA (1992). Water and Wastewater Equipment Manufacturer's Association, Inc. Comments on the
 Ground Water Disinfection Rule.                                                         ,

 Zukovs, G., et al. (1986). "Disinfection of Low Quality Wastewaters by Ultraviolet Light Irradiation."
J. Wat. Pollut. Control Fed.  Vol. 58, pp. 199-206.
UV Light Disinfection Technology in
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3-44
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                  CHAPTER 4.  OPERATIONAL CASE STUDIES
  4.1    INTRODUCTION
  In this chapter, ultraviolet light operational case studies are presented.  The purpose of this chapter is to
  provide brief summaries of available information from public water systems (PWS) that have installed
  ultraviolet (UV) treatment for ground water disinfection.  The availability of information from operators
  of PWS systems or the lack of it provides insight into  the practicality of using ultraviolet treatment.
  Operators' information provides an opportunity to assess actual field experiences. Such assessment helps,
., in determining the degree and level of operation and maintenance this technology requires and provides
  a realistic estimate of the expenses incurred by various communities to obtain and maintain an ultraviolet
  system.                                             -

 In general, case studies indicate actual performance evaluation of the technology investigated, and indicate
 realistic operation and maintenance problems for specific site  conditions. Ultraviolet light technology .
 application case studies  also serve as an indicator for the acceptance or rejection of technologies that are
 not well established, (or accepted by the scientific community or by the USEPA as a reliable technology)
 to disinfect drinking water.

 The case studies also may serve as indicators of the price small and often rural and isolated communities
 are willing to'pay in the absence of State mandates for ground water disinfection.  Another aspect of these
 case studies is reported water use and production capacities  in Transient Non-Community (TNC) arid Non-
 Transient Non-Community (NTNC) water systems.  The information reported by the operators of very
 small TNC and NTNC systems shows that average water production appears to be much less than the
 water consumption generally assumed in calculating treatment costs for Community Water Systems (CWS)
 with similar population sizes. In addition to the ultraviolet light application in drinking water case studies,
 this chapter also presents information collected from two ultraviolet light equipment service contractors
 and a general discussion of ultraviolet units costs as demonstrated from the case studies and the design
 flows of the investigated systems.  Finally, this chapter presents suggested criteria for the use of ultraviolet
 light units based on the interviews conducted to develop the case studies.
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                              Chapter 4—Operational Case Studies
 The case studies presented from the State of New Jersey are for TNC and NTNC ground water. The case
 study presented from the State of Oregon is a ground water CWS case study. A surface water case study
 from the State of Montana and a brief case study from the State of Maryland where ultraviolet light is
 used in a wastewater reclamation facility are presented. Moreover, one case history from the Netherlands
 is presented.

 To obtain information about drinking water systems that have installed ultraviolet light technology for
 disinfection, the USEPA contacted drinking water program supervisors in four states (New Jersey,
                                                               "     -             >        '
 Montana, Oregon, and California).  The State of New Jersey provided the name, address, and contact
 person  telephone number for twenty drinking water facilities  that  use ultraviolet light for primary
 disinfection (Monaco, 1996). The State of Oregon provided information on the single public water system
 that uses ultraviolet light for primary disinfection and chlorine as a secondary disinfectant.  The State of
 California informed the USEPA that  they are not aware of any PWS systems that have installed an
 ultraviolet light unit to disinfect drinking water.  The State of Montana provided the telephone number
 of the contact person in a PWS that uses ultraviolet light for primary disinfection.

 Apparently there are many private non-community water systems that use ultraviolet light for disinfection
 in the State of Oregon1  and in the State "of New Jersey2. These private/water systems include private
 homes and  small shops.  Interviews, conducted with two water treatment units service contractors,
presented in this report, show the extent to which very small communities, families and individuals are
 willing to go to have safe disinfected drinking water available on demand.

Most of the information presented in this chapter was collected through telephone interviews with systems'
managers or operators.  The  information provided here on  the CWS that uses ultraviolet light for
 disinfection in the State of Oregon  was collected by the State. The information collected via telephone
interviews  with system operators  or  through field visits by State representatives  were based on  a
 questionnaire that covers basic  information on operation and maintenance, system costs and water quality
parameters and compliance.  The questionnaire is presented in Appendix C.
    'Personal communication with Mr. Gary Burnett and Ms. Kari Sails of the Oregon Drinking Water Program
(5/20/96).
    Personal communication with Mr. Pete Cicalese an ultraviolet light equipment service contractor (fi/27/96).
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                               Chapter 4-—Operational Case Studies
  Newly proposed ultraviolet light use regulations developed by the State of New Jersey are included in
  Appendix D.  Also, Appendix D includes drinking water regulations from the State of Utah, and the U.S.
  Department of Health, Education, and Welfare (DHEW) [now the Department of Health and Human
  Services (HHS)] 1966 Policy Statement on the use of ultraviolet light for drinking water disinfection.
  While theproposed regulations for the use-of ultraviolet light in the State of New Jersey require the same
  minimum dose (16 mWs/cm2) mandated under current State regulations, the new regulations specify some
  construction and light monitoring requirements (New Jersey, 1995).  The ultraviolet light disinfection
  application regulations in the  State of Utah appear to be modeled oh the DHEW regulations.  .

  4.2    CASE STUDIES FROM THE STATE OF NEW JERSEY
  The case studies,presented from the State of New Jersey cover mainly TNC and NTNC systems and
  reflect satisfaction with ultraviolet use for disinfection. The systems in these case studies draw their water
  from ground water sources. All ultraviolet light units were reported to operate 24 hours per day and the
 majority had one unit in operation without a backup unit onsite. These case studies include a TNC system
 that has been  in operation for more than 10 years.  Another case study presents a TNC  system that
 switched from chemical disinfection to ultraviolet disinfection.

 Examining the information collected from the case studies conducted in the State of New Jersey revealed
 that  ultraviolet, units receive little attention and require very little supervision.   On the  other hand
 operators of the PWS do not  know much about the technology or the  units that were purchased and
 installed, Basic water quality parameter information is typically not kept onsite and certain parameters
 that could affect.the disinfection efficiency of an ultraviolet unit such as iron or turbidity had never been
 tested.  Very few operators know the minimum ultraviolet dose their unit could provide.  Not a single
 PWS operator or contact person complained about operation and maintenance costs. All contacted persons
 praised the minimum service time ultraviolet units require and how practical it is to use such a technology.
 All the persons who had experience with chemical disinfection equipment complained about equipment
 monitoring and service time and costs.in  contrast to ultraviolet treatment operational requirements.  In
 addition, it appears that in most of these systems installation costs were very minimal, as were engineering
 requirements and site modification.

 4.2.1  PWS in Phillipsburg, New Jersey
The  public water supply system in Phillipsburg, New Jersey, serving about 30 persons, installed its
ultraviolet light disinfection unit in October 1995.  The age of the majority of the population served is

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                              Chapter 4—Operational Case Studies
 above 47 years (range 47 years to 98 years). The disinfection capacity of the. unit, at 30 mWs/cm2- is 20
 gpra (29,000 gpd).  The  system has no backup unit and no storage capacity.  The reason given for
 favoring ultraviolet disinfection over chlorination is the dislike of chlorine taste and that in ultraviolet
 treatment, chlorine and chemicals do not have to be added to drinking water.  The unit is equipped with
 a 5 micron filter, a light emitting diode, a sound alarm and a manual wiper.  The ultraviolet light unit is
 a closed ultraviolet light unit, made in Vermont and came with a 1-year warranty on parts. According the
 manager of the system the ground water source is of "good quality". There are no turbidity measurements,
 but according to  the contact person, the ground water is clear and ,the turbidity may be assumed to be
 "very low". There have been no conform outbreaks from the time the system was installed.  Once a week,
 in a few seconds, the system manager would manually clean the bulbs by pulling and pushing the arm of
 the manual wiper a few times.  No detergents or chemical agents are used in the weekly cleaning.  During
 the annual service, the ultraviolet light bulb is changed (i.e., once every 9,000  hours) and the unit is
                                                                 t
 thoroughly cleaned.  The capital cost of the system was $2,100 including engineering, installation and
 instruction.  The operation and maintenance cost is estimated at $90 to $100 per  year.  /

 4.2.2   TNC in Lebanon, New Jersey
 The ultraviolet light disinfection equipment at this TNC in Lebanon, New Jersey was installed near the
 end of the year 1994. Before installing the present unit the facility had an old ultraviolet light unit that
 could not be maintained any longer.  The present unit serves an average of 50  persons per day.  The
 owners of the facility estimate water consumption at 200 gpd. The unit's design flow is 15 gpm (21,600
 gpd). Part of the facility that uses the unit is a restaurant.  The negative effect of chlorination on water
 taste and the operation and maintenance requirements for chlorinators favored the use of ultraviolet light
 technology over traditional chemical disinfection technology.  The system has a  storage capacity of 80
 gallons. The unit delivers a minimum dose of 17 mWs/cm2 assuming water with an absorbance coefficient
 of 0.1 (a level between an absorbance coefficient of 0.06 for municipal drinking water and ah absorbance
 coefficient of 0.15 for sea water).      •                                                      .

The unit, manufactured in Pennsylvania, is equipped with a mechanical wiper, a sound alarm system, and
 one ultraviolet lamp, and is made out of stainless steel. It came with a 1-year warranty.  Water tests have
 shown no presence of total coliform in the finished water. The person who services the system said that
he has not noticed any biofilming in the storage tank or the pipes connected to the ultraviolet light, unit.
The unit is cleaned with synthetic detergents and alcohol. The owners of the facility say that once a year
the bulb is changed and the full service cleanup takes  about 1/2 an hour. The capital cost was estimated
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                               Chapter 4—Operational Case Studies
 at $2,000 to $3,000 (including engineering and installation). The operation and maintenance is contracted
 out. The operation and maintenance costs for the system are estimated at $500 per year including all
 quarterly water sampling, analysis, testing and reporting requirements.

 4.2.3  TNC in Branchville, New Jersey
 The ultraviolet light system was installed in 1990-1991.  It serves an average population of 40 per day.
 Ultraviolet light was considered because of its effectiveness against nuisance microorganisms and because
 it does not add any taste to the water. Before installing the ultraviolet light unit, disinfection was available
 through an iodinator. The use of chemical disinfection was not satisfactory because of its effects on the
 taste of the beverages served at the facility such as tap soda.  In addition, some operation and maintenance
 problems associated with the chemical disinfection unit, such as measuring and applying the right chemical
 dose, brought the owner to the decision of installing an ultraviolet unit with the promise that it requires
 little attention. The unit was manufactured in the United States and is equipped with one light bulb and
 a sound alarm system. The system has a storage capacity of 40 gallons.

 Turbidity levels and iron levels are unknown. However, for some time the system was. equipped  with a
 softener which at the time of the interview had not been, used for over a year and a half.  There were no
 eoliform or other microbiological outbreaks;

 Service of the ultraviolet light unit is contracted out to the firm that installed it. The unit is serviced once
 per year.  The service includes cleaning the unit and replacing the light bulb.  The annual service of the
 unit takes about 20 minutes.  As stated earlier the unit was put in service 5 to 6 years ago, nevertheless,
 no diodes, ballasts, or sleeves have been replaced. Moreover, the owners of the facility have not noticed
 any biofilm accumulation in the pipes or the storage tank. The cost of the system including engineering
 and installation was $1,500.  The operation and maintenance cost is estimated at $125 to $150 per year.

 4.2.4  NTNC in Harmony Township, New Jersey
The ultraviolet light unit at this system was installed in the winter of 1994. The unit is a closedrtype unit.
The treated water is used by 20 employees for showering and washing only.  The owners of the facility
provide bottled water for drinking.  The average water consumption is about 10,000 gallons per day. The
ultraviolet light unit has the capacity of treating 24 gallons per minute (34,560 gallons per day).  Water
treatment includes an activated carbon filter installed before the ultraviolet unit.  The facility where the
ultraviolet unit is installed is a  chemical manufacturing  facility.  The ultraviolet light unit was

UV Light Disinfection Technology in
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                               Chapter 4—Operational Case Studies
 manufactured in New Jersey and came with a 1-year warranty on parts.  The-unit is equipped with two
 ultraviolet light bulbs, a sound alarm  system and mechanical wipers.  The quarterly tests for coliform
 bacteria in treated waters show an absence of coliforms.                               ,
                                                                               i
 The unit is serviced once every 6 months.  It takes about one person-hour to clean and service the unit.
 Iron deposits are removed using dilute acids.  The installer did not provide any special training for the
 employee  who services the unit.  Bulbs are replaced when ultraviolet light emission is  at 50 percent of
 the maximum power.  The .caretaker of the unit could not provide any information on the intensity of the
 unit or its dose.  Installation and capital costs  are not known, however, the operation and maintenance
 costs are estimated at $1,000 per year.

 4.2.5   TNC in Ringoes, New Jersey          '
 This TNC  system in Ringoes, New Jersey, is a deli store with 12 regular employees. It serves about 300
 persons per day.  The ultraviolet unit was installed in 1985. .The reason for selecting  ultraviolet light
 treatment over chemical treatment is unknown to the current owners.  The unit is a closed-type Unit
 equipped with one ultraviolet light bulb and a  water meter. The unit is not equipped with a light or a
 sound  alarm system or any other accessories.   The current owners do not know  where the unit was
 manufactured and could not tell whether it was covered by any form of a warranty. The system has a
 storage capacity of 50 gallons.  The water is pre-treated by means of a "paper-like" filter of unknown pore
 size. This  filter removes some silt and sediments. The operators could not provide any information on
 the ultraviolet light intensity the unit is capable of delivering.

 The unit is cleaned once a year. The cleaning  is done manually and the unit is flushed with a chlorine
 solution.  During the past 10 years there has  been one positive coliform test, in  1992.  The owners
 attribute the positive coliform test to the fact that the ultraviolet light bulb was not changed in a year and
 half.                                    '.'..'.'

 The owners could not provide any information  on capital, installation and operational and maintenance
 costs.  However, the owners expressed satisfaction with the performance of the unit as it requires very
 little attention on their part and its service is contracted out to a plumbing company.
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                               Chapter 4—Operational Case Studies
  4.2.6  NTNC in Ringoes, New Jersey
  According to the contact person at this PWS, this system provides water to about 30 residents in an
  apartment building, and a store with 3 employees which serves about 50 to 100 customers per day.  The
  system was installed 7 years ago.  The new owner does not know why ultraviolet light was selected by
  the previous owner.  According to the  store manager where the ultraviplet light unit is located, the
  ultraviolet light system is an open-type unit.  The'unit is installed in a storage room. The contact person
  knows that the unit is working by looking at  the blue light coming from the unit (ultraviolet light units
  do emit some gray-blue visible light).   Microbiological  tests are conducted by the  county health
  department.  The new owner did not know that the unit needs periodic service such as  changing the
  ultraviolet light bulbs or occasional service such as cleaning. According to the contact person there is no
  sign at the door where the ultraviolet light unit is located to warn the users  of that room that  looking
  directly at the light emitted from the ultraviolet lamps is  hazardous and could cause temporary and
 permanent eye injury.  Store employees,  where the unit is located, did not appear to be warned in any
 manner against gazing at the unit with its serene blue light.
                                                                -.-.      ' f •'.--"-.
 4.2.7  NTNC in Stewartsville, New Jersey
 This NTNC system is located in a metal work manufacturing facility.  The population served is 50 persons
 per day.  The capacity of the ultraviolet unit is 20 gallons per minute (29,000 gpd). The intensity and
 dose of the unit are not known. The unit was installed, in 1991, when for the first time the ground water
 source tested positive for cohTorm bacteria.  Because the water source is contaminated with hightevels
 of nitrates and nitrites,  the treated water isjised  only for washing,  sanitation  and  toilets flushing.
 According to the contact person at the facility, the source of ground water contamination is a 1.5 million-
 chicken farm, located about 2 miles away from the facility.  According to the  contact  person, the well
 water is tested by the county department of health for microbial contamination once every 6 months and
 possibly for nitrates/nitrites. The ultraviolet unit installed 5 years ago was manufactured in the  United
 States, it contains two ultraviolet light bulbs and came with a 2-year warranty ;on parts. The system does
 not have any storage capacity. There has been no positive coliform test after the installation of the unit.
 Twice a year, the unit is fully serviced.  This service includes replacing the bulbs and cleaning the unit
 with detergents.  The full service is done by one person and it takes several hours to complete.  The unit
 cost including engineering and installation was about $1,000. The operation and maintenance costs are
 estimated at $200 per year.     _
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                             Chapter 4—Operational Case Studies
 4.2.8   TNC Ground Water System in Washington, New Jersey
 Merrill Creek Visitors Center in Washington, New Jersey, is a transient non-community water supply
 system. The system has three sites where ultraviolet light is used for ground water disinfection. The sites
 include a visitors center, a rental property (guest houses), and a pump house.

 The Center has four closed ultraviolet light units—three units each with one bulb and one unit with four
 bulbs (guest houses site).  The operator could not provide information on the dose or intensity used. The
 population served is estimated by the operator to be between 5,000 to 10,000 per year. The system is not
 equipped with  an  alarm  or telemetry system.  The  system is a U.S.-made  system, -manufactured in
 California.  It was -installed 8  years ago.  There is no  distribution system and the system has no storage
 capacity. Also, chlorination is not used as a secondary disinfection.

 There are no turbidity measurements taken.  There have been no conform outbreaks and no biofilm
 formation in the pipes within the buildings. The system uses a pH adjuster on only one site and applies
 hardness and iron removal treatment prior to ultraviolet treatment.  Microbiological samples are taken on
 a monthly basis. Cleaning of the units is performed once HPC reaches 100 CFU/ml. If the HPC count
 remains high, the light bulbs are replaced. Also, light bulbs are changed annually; during the past 8 years,
 only one faulty ballast was changed; and no diodes have been changed. The system is not equipped with
 wipers or ultrasonics.  Cleaning of units occurs once  every 6 months and it takes 2 hours to finish the
 cleaning process. The operator mentioned that over the last 8 years only two quartz sleeves were broken
 during maintenance.

The estimated O&M costs are $100 to $200 per year, and the capital costs for one of the units, including
 pH adjuster and softener, were  approximately $4,000 to $5,000 (personal communication with the
 supervisor, 1996).

4.3   CASE STUDIES FROM THE STATES OF OREGON, MONTANA, AND
       MARYLAND
The case study presented from the State of Oregon covers a ground water CWS. The case study reflects
satisfaction with ultraviolet use for primary disinfection. The four ultraviolet units installed in this CWS
operate 24 hours per day.  A  close look at the information presented in this case study shows that the
theoretical flow capacity of this CWS system is 100,800 gallons per day or 70 gpm.  The theoretical
disinfection capacity of the installed ultraviolet units  is even greater at 115,200 gallons per day.  The
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                               Chapter 4—Operational Case Studies
  USEPA assumed design flow category for a CWS population of less than 100 persons is 24,000 gallons
  per day or 16.67 gpm. The USEPA average flow category for a CWS population of less than 100 persons
  is 5600 gallons per day or 3.89 gpm. The ratio of USEPA design flow category to the USEPA average
  flow is 4.3.  Some authorities use a factor of three for instantaneous peak factor (i.e., maximum water
  demand/average water demand per day) (Masschelein,  1992). Using the USEPA peak  factor figure to
  determine average water demand would yield 245 gallons per capita per day (population  served 96).  An
  average water demand of 52 gpd is normally considered to calculate water demand in very high-standard
 residential areas (Masschelein, 1992). The case study from Montana is a Ranney-filtered drinking water
 application.  The case study from Montana reflects satisfaction with ultraviolet application for primary
 disinfection.  The case study from Maryland covers a water reclamation facility that uses an open channel
 ultraviolet system.  The  case  study from Maryland reflects satisfaction with ultraviolet application  for
 treated wastewater disinfection.    .

 4.3.1   Villadom Mobile Home Park CWS In Umatilla County, Oregon
 Only one public water system in Oregon has installed ultraviolet light  for primary disinfection, with  '
 chlorination providing secondary disinfection.' This community water system, Villadom Mobile Home
 Park is located just north of Milton-Freewater, in Umatilla County.  The system has a well  with a capacity.
 of 70 gpm, and serves a population of 96.

 Ultraviolet light was first considered at Villadom in 1990, but was-not chosen as  a disinfectant until June
 of 1994 when a  series of samples (May and June) tested positive for total coliform. With no existing
 disinfectant capabilities, the owner decided to install bpth an ultraviolet light system, and a liquid sodium
 hypochlorinator to provide the required residual. Household bleach (5.25%) is used and diluted 1:5. The
 owner chose not to use chlorine as the main disinfectant due to the undesirable taste and high maintenance
 needs.

 The ultraviolet light system installed, Water Soft model UV-20F, is a stainless steel cylinder with a space
 requirement of 13 x 7 x 36 inches per unit.  The system uses four units in parallel, each  preceded by a
 120-mesh  screen filter, to provide a maximum capacity of 80 gpm  (note:  this capacity exceeds well
capacity).  The shipping  weight of  each unit is 23 pounds.   The dose provided  by each unit is  30
mWs/cm2.  Each unit has a capacity of 20 gpm,  and is equipped  with' an automatic  shut-off valve
("Failsafe" brand) in case of a malfunction or a weak bulb.  The shut-off valve is also hooked up to an
alarm.  The manufacturer location is  unknown, as Water Soft purchased the product and  marketed it as

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                              Chapter 4—Operational Case Studies
 a Water Soft product. Pump and Drilling Supply, located in Wilsonville, OR, was the distributor for these
 units, but the line has been discontinued. The distributor offered a 1-year warranty, but overall the CWS
 system operators have not found any major problems with the product.

 Villadom Mobile Home Park has a storage capacity of 75 gallons, from three pressure tanks.  The feed
 pump for chlorination is a 28 gpd capacity Mec-a-Matic, with a theoretical dosage of 1.6 ppm. However,
 at the time of the field visit, a chlorine residual was barely detected (<0.2 ppm).  The owner was not
 available for further questioning.

 Turbidity levels for this system are not known. The source is a 48 foot deep well, and sand entering the
 treatment system has been an occasional problem in the past. No problems other than complaints about
 the aesthetic water quality were experienced.  There is no noticeable iron in the source water, although
 there is no record of any lab analysis results. All monthly tests for coliform bacteria after June 1994 have
 been negative.  The chlorine residual is not routinely measured at the time of sample collection, so the
 level of protection provided by chlorine is unknown. No increase in biofilm formation has been noticed
 in the PVC distribution pipe. No other microbiological problems are known.

 The pre-filters would be cleaned only when sediment builds up, and this has not been necessary in the 2
 years the system has been in operation.  The ultraviolet units are cleaned with alcohol whenever the bulb
 is changed. With the Failsafe  feature, the unit ceases  operation if the ultraviolet light bulb  is out or
 weaker than the set dosage.  The local supplier is on call for any operation or maintenance needs.  The
 supplier attended a 4-day "Water Soft" seminar covering all aspects of the ultraviolet light units in order
 to be able to sell and service them.  He changes  the light bulb at least every year, and cleans  the glass
 sleeve at that time. It takes one person about an hour and a half to accomplish both of these tasks on all
 four units.   He has never broken a sleeve or bulb during cleaning or changing, though he says it is
 common with inexperienced private  homeowners. The sleeves, diodes, and ballasts have not yet needed
 to be replaced, and the safety  valve would shut the unit off should anything go wrong.  As far as
 calibration, the only adjustable parameter the service person knew of was the capacity, which is  designed
for 20 gpm per unit but could be lowered using the flow control  valve,

The  cost of the ultraviolet light system was about $20,000.  Each 20 gpm unit costs $5,000, including
engineering and installation.  Operation and maintenance costs  are as little as $550 per year,  which
includes materials and labor (about an hour and a half to change, the bulbs and clean the sleeves).
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                               Chapter 4—Operational Case Studies
  4.3.2V  Fort Benton, Montana
  The city of Fort Benton, Montana, obtains drinking water from the Missouri River.  The filtration plant,
  which is more than 20 years old, was in need of upgrading due to coliform bacteria outbreaks.  Rather
  than building a new filtration plant, the city built a new 0.088 m3/sec (2 MOD) treatment plant in 1987.
  Water is drawn through Ranney collectors installed 6 to 7.5 m (20 to 25 ft) below the river bed, a system
  that allows the river bed to naturally filter the raw water. Turbidities of water entering the treatment plant
  average 0.08 NTU.  No Giardia cysts have been found in the flow from the Ranney collectors.

  The water is treated with ultraviolet radiation fof primary disinfection, then chlorinated for secondary
  disinfection.  An applied chlorine dosage of about 1 mg/L is used.  The entire water treatment system is
  housed in a 2.97-m2 (32 sq ft) building.

  The ultraviolet disinfection system consists of six irradiation chambers, two control cabinets with alarms,
  chart  recorders, relays, hour-run meters, lamp and power on-lights, six thermostats, electrical door
 interlocks, mimic diagrams, and six ultraviolet intensity monitors measuring total ultraviolet output. Each
 irradiation chamber contains one 2.5 kW mercury vapor, medium-pressure arc tube, generating ultraviolet
 radiation including radiation at 253.7 nm.
                    i      "       . -                •..,.•      .      .      -   •  • -     •

 The initial ultraviolet dosage is 41 mWs/cm2 at maximum water flow of 104 L/S (1,650 gal/min) through
 each irradiation unit. Expected arc tube life is 4,500 operating hours, providing a minimum .ultraviolet
 dosage of 25  mWs/cm2 at 253.7 nm.  These conditions were assumed to reduce concentrations of
 Esckerichia coli organisms by a minimum of 5 logs (10s reduction) (USEPA, 1989).

 The system (made in EnglandXis equipped with a telemetry control system and fully  automated backup
 system.  Each bank of three irradiation chambers has two units on-line at all times, with the third unit
 serving as backup.  In the event that the ultraviolet intensity drops below acceptable limits (20 mWs/cm2
 in any of the chambers), the automatic butterfly valve on the standby unit will open.  The alarm system
 also is activated if ultraviolet intensity drops below acceptable limits in any of the chambers.  The
 ultraviolet alarm system is  interfaced with an automatic dialer and alarm system.

 In 1987, total equipment costs for the six-unit ultraviolet irradiation system with butterfly valves  were
 $74,587 (USEPA; 1989). The current population served by the system is about 1,700. No outbreaks of
UV Light Disinfection Technology in
Drinking Water Application—An Overview    4-11                       Final-September 1996
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                             Chapter 4—Operational Case Studies
 conform bacteria have occurred since the installation of the ultraviolet unit.in 1987, and the system is
 cleaned once a year (personal communication 'with superintendent, 1996).

 4.3.3   Mayo Water Reclamation Facility, Maryland
 In the Greater Washington, D.C. area, the Mayo Water Reclamation Facility (that treats gray water before
 discharging it into a river) uses ultraviolet light for disinfection. The Mayo Water Reclamation Facility
 is located in Anne Arundel County on the Eastern Shore of Maryland, near the town of Edgewater. The
 ultraviolet disinfection system is  an  open-channel system that has been in operation for 7 years.  The
 system was designed and built by Trojan and disinfects a peak flow of about 0.5 MOD. The BOD levels
 are about 90 mg/1, and the suspended solids levels are about 60 mg/1.  The effluent from the ultraviolet
 disinfection system is discharged directly to Rhode River.   The dose  applied at the Mayo water
 reclamation facility could not be verified by the current operator.

 An early problem in operating the system was rapid algae growth in the ultraviolet unit. The problem was
 corrected  by  covering  the open channel and preventing the sunlight from reaching the  water.  The
 operation and maintenance crew clean the ultraviolet lamps weekly with diluted HC1 solution. The unit
 is equipped with an intensity meter to indicate when the lamps must be- cleaned and an alarm system to
 indicate a lamp failure.  Although the manufacturer recommended that lamps  be replaced once  a year,
 according to the operator, some lamps that were put in operation  a few years ago are still functioning
 satisfactorily (personal communication with operator, 1995).

 4.4   CASE HISTORY, LANDEUS WATER TREATMENT PLANT IN THE
       NETHERLANDS
 Kruithof et al. (1992) presented a ground water treatment plant case history from the Netherlands.  The
 case history shows that ultraviolet light was used  at the Landeus water treatment  plant following an
 outbreak of coliforms and Escherichia coli bacteria in 1980. In the 5-year period (1981-1985) following
 the installation of an ultraviolet light  disinfection system, Escherichia coli tested positive in the finished
 water five times of 200 measurements.  Simultaneously, the source water total coliforms were detected
 116 times and Escherichia coli were detected 65 times. The reason for Escherichia coli presence in the
finished water (five times out of 65 Escherichia coli detection in  source water) was low ultraviolet
radiation dose.  In three cases, the cause of the low  dose was a malfunctioning  ultraviolet light intensity
monitor showing a higher dose than the actual.  In the other two cases, the dose was experimentally
reduced to 23 mWs/cm2, a level that did not eliminate all coliform bacteria.  In the 6 years that followed

 UV Light Disinfection Technology in
Drinking Water Application—An Overview     4-12  .                     Final-r-September 1996
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                                Chapters—Operational Case Studies
   the year 1985, no Escherichia coli outbreaks occurred. The no-outbreak period came following more
   accurate monitoring and routine lamp replacement at 60 percent (24 mW/cm2) of the original intensity (40
   mW/cm2).  No capital or operation and maintenance coks were  reported by Kruithof et al. (1992).
   However, Kruithof etal.  (1992) reported costs associated  with the use of ultraviolet light for drinking
   water disinfection for other treatment plants in the Netherlands.  The costs reported by Kruithof et al.
   (1992) are presented in chapter 3.

   4.5    PERSPECTIVE OF TWO WATER TREATMENT UNITS  SERVICE
          CONTRACTORS
   As the case studies have revealed, many ultraviolet units operation and maintenance services are contracted
   out to professional contractors or plumbing firms, and these are typically the same firms that market and
,   install the units. This indicates that some ultraviolet units are sophisticated enough to warrant professional
   assistance particularly when thorough cleaning is required.  Two contractors were interviewed to provide
   information that  the contact  persons could not  provide  about  their systems'  ultraviolet light  unit.
   Moreover, the contractors were asked two specific questions that raised some concerns about possible
   environmental impacts of spent ultraviolet light bulbs, and about actual operation and maintenance costs.
   The first question was about the fate of the spent bulbs." The second question was about how often bulbs
   and sleeves get broken when being installed or replaced. The fact that ultraviolet light bulbs contain some
   mercury, and  that at least in  one  State (California) wastewater treatment plants  utilizing ultraviolet
   technology for disinfection are required to recycle spent bulbs, prompted the first question. The second
   question was in response to claims that the expensive ultraviolet light bulbs and sleeves often break during
   cleaning and replacement.                      '

  The interviewed contractors, in New Jersey and the other in Umatffla county, Oregon, said that ever since
  they started servicing ultraviolet units, they have not broken any ultraviolet light bulbs. The contractor
  in New Jersey said that his  firm services well over 150 ultraviolet units per year.  The contractor admitted
  to breaking one sleeve 3 years ago.  Both contractors  indicated that bulbs and sleeves do break if an
  inexperienced person like a homeowner tries to do  the job himself or herself. Usually people try to do
  the replacement themselves in the first or second year of installing the unit.  Then when the expensive
  bulb breaks they ask for help.                                           :

  The contractor in New Jersey said that spent ultraviolet light bulbs are disposed of along with regular
  trash.  The contractor in Oregon said that spent bulbs are disposed of along with other toxic substances
  UV Light Disinfection Technology in
  Drinking Water. Application—An Overview    4-13                       F/na/—September 1996
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                             Chapter 4—Operational Case Studies
in a toxic wastes landfill.  When asked if spent bulbs break in the shop or before being disposed of during
transportation or storage, the contractor in Oregon said that never happens because the bulbs come in well
padded corrugated cardboard boxes.  When'asked if he thinks that spent ultraviolet light bulbs constitute
an environmental hazard his response was that the amount of mercury in the bulbs is less than the amount
one would find in the old electric heating and air conditioning switches installed in homes, therefore the
pollution risk in his view is small.

The contractor in New Jersey estimates his service charge at an average of $175 per Unit, with one light
bulb per year. This includes changing the bulb and the "O" rings, and cleaning the unit.  The contractor
in Oregon charges $46 per service call plus parts.

The contractor in Oregon  services chlorinators also, including that used for secondary disinfection at the
ViUadom Mobile Home  Park  CWS.  Servicing a chlorinator is time consuming and requires close
attention.  The  service includes checking and cleaning the valves once every 2 mpnths and testing the
chlorine level once per week. It also entails filling the chlorine tank and preparing the solution once every
3 days. His fees for these services are the same as those for servicing an ultraviolet unit (i.e., $46 per
service call plus materials with each service call lasting for about an hour).  The contractor in New Jersey
also services chlorinators at private homes and very small private water systems! The contractors' remarks
                                             -      .          ,._>_.
on chlorinators were similar to those expressed by the service contractor in Oregon adding that the  service
requirements are cumbersome to private home owners and time consuming to the service worker.

Both service contractors indicated that they have not noticed any biofilm accumulation in pipes or storage
tanks and did not need to change diodes. According to the contractor in New Jersey, ballasts are changed
once every 4 years, mostly because of improper use or lightening. The contractors experience with the
industry indicates that the ultraviolet industry stands behind the quality of its products and the parts it
supplies.

4.6   COSTS OF ULTRAVIOLET LIGHT UNITS AND DESIGN FLOWS OF TNC
       AND NTNC SYSTEMS AS REVEALED FROM THE CASE STUDIES
The costs of the ultraviolet light treatment units reported in these case studies reflect actual costs incurred
by these  systems.  The installed equipment  costs for treating flows  less  than 100,000 gpd ($1,000 to
$5,000), vary greatly although the units provide similar disinfection power to almost similar flows. The
reported capital costs reflect the variance in price quotes obtained  directly from.ultraviolet light unit
UV Light Disinfection Technology in  .
Drinking Water Application—An Overview    4-14                       Final—September 1996
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                                Chapter 4—Operational Case Studies
   manufacturers and reported in Chapter 3 of this report. The same observation, can be made when looking
   into the reported operation and maintenance costs ($90 per year per unit to $200 per year per unit). The
   operation and maintenance costs reported in Chapter 3. of this report are comparable to those reported in
   these case studies (the-operation and maintenance costs reported in chapter 3 of this report are higher
   because they include power costs and other miscellaneous costs  for ultraviolet units with higher dose
   capabilities).  None of the investigated PWS systems were equipped with telemetry equipment.  The
   benefit of equipping water systems troubled with microbiological and monitoring Violations is reported
   in a case study  from California (USEPA, 1995), In this case study installing telemetry equipment reduced
   operation and maintenance costs by about 33 percent.  This was  in a rural California.system that was
   plagued with bacteriological and monitoring violations.  Installing  telemetry  equipment reduced the
   required daily inspection visits to weekly visits, thus reducing the time required to operate and maintain
   the system to 13 hours per month including travel time.                    '

   The flows reported in the case studies above show that many small systems have some storage capacity.
   Having some storage capacity helps in reducing the peak demand on the treatment plant.  This reduction
   in peak demand at the treatment plant also translates into installing equipment with smaller capacity and .
   hence lower capital and operation costs. The case studies also show thatjn small systems, using chemicals
   to maintain residual  disinfection in the  network might not be  necessary.   As stated earlier the flow
   requirements  for  TNC and NTNC systems might not be the  -same as those of CWS  with similar
   population.  This area warrants further investigation as it  bears  heavily on treatment options and cost
'  estimates.

  4.7    SUMMARY OF FINDINGS
  The presented case studies revealed important commonalities in general systems' features and in specific
  operation and maintenance procedures. Examination of the information collected from the.case studies
  shows the following:

         • All the investigated systems have ultraviolet units with disinfection capabilities for flows that
           exceed actual water' demand. The summary table presented below clearly shows that the per
           capita water consumption availability atthese systems exceeds, by far, normal residential water
           consumption demand. The reported estimate of average water consumption at the TNC  PWS
           in Lebanon, NJ is 4  gallons per capita per day while  the system's  conservative available
           average demand capacity is at 100  gallons per  capita per day.  Installing equipment with'
           appropriate capacity and having some storage capacity  would certainly result in lower capital
           costs  and operation costs.
  UV Light Disinfection Technology in
  Drinking Water Application—An Overview    4-15                       Final—September 1996
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                              Chapter 4—Operational Case Studies
        • All ultraviolet units operate 24 hours per day.       s            .

        • There are no backup units available onsite:

        • Maintenance is contracted out.

        • Operation and maintenance costs were not specifically raised as a concern.

        • Installation costs are part of the equipment costs and site modification are either minimal or not
          necessary.  Space requirements are very small and the weight of a single unit is less than 25
          pounds.

        • Chemical and physical water quality parameters are often not known.

        • No coliform violation occurred with ultraviolet treatment.

        • No biofilming in networks pipes or reservoirs occurred.

        • Operat6rs and users expressed satisfaction with the performance of the installed ultraviolet units,
          and the simplicity of its  operation and maintenance requirements.

        • Sleeves and bulbs breakage was not specifically reported as a concern.

                                                                   f
Exhibit 4-1 presents a summary table of ultraviolet light disinfection applications in drinking water based

on case studies.
UV Light Disinfection Technology in
Drinking Water Application—An Overview    4-16                        Final—September 1996
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                               Chapter 4—Operational Case Studies
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-------
                             Chapter 4—Operational Case Studies
4.8    SUGGESTED CRITERIA FOR THE USE OF ULTRAVIOLET LIGHT UNITS
        BASED ON THE PRESENTED CASE STUDIES

Based on the interviews conducted with operators of public water systems using ultraviolet light to

disinfect drinking water or water for human consumption, the following requirements are suggested for

the use of ultraviolet units in small public water, systems:


        •  All units must be of the closed-type.

        •  Mechanical  wipers and ultrasonic cleaners should be mandatory if water fouling agents such
          as iron are present in the water entering the unit.

        •  Annual cleaning of the unit, at a minimum.

        •  Minimum set dose at any wavelength(s) within the 250nm to 270nm spectruni (this needs to
          be  decided by the work group).

        •  Automatic shutoff valve, flow control valves with shutoff triggered when light intensity falls
          below the minimum set level.

        •  Sound and light alarm and-telemetry equipment if users or operators' are not close by.

        •  The unit body needs to be made of material that would  not permeate or degrade under the
          effect of ultraviolet light, such as high quality stainless steel.

        •  Testing the disinfection efficiency of the unit as a whole by means of bioassay or actinometry
         before installation.  Research might be necessary to determine whether recalibration of the
          installed unit is necessary after years of service.  Testing the unit's ballasts and diodes after
         years of service ajso requires some research to determine the time span when such testing might
         be necessary.                   '                                     .               .

        • Microbiological tests for ultraviolet treated finished water should include HPC tests.  HPC
         microorganisms may provide a better assessment  of disinfection than the ultraviolet sensitive
         coliforms.                                                                         .

        • Education of the users and the servicepersons about the hazardous compounds contained in the
          components  of the ultraviolet light unit and proper ways of disposing spent parts.

        • When possible a backup unit should be available or at least one set of spare parts stored onsite.
UV Light Disinfection Technology in
Drinking Water Application—An Overview    4-18                      Final—September 1996
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                             Chapter 4—Operational Case Studies
 4.9    REFERENCES

 Kruithof, J.C., Van der Leer,  R.C., and Hijnen, W.A.M. (1992).   "Practical Experiences with UV
 Disinfection in the Netherlands."  Aqua, Vol. 41, No. 2, pf>. 88-94.

 Masschelein, W. J. (1992). Unit ^Processes in Drinking Water Treatment. Marcel Dekker Inc. New York!

 Monaco Vince, (1996). Memoranda to Dr. Faysal Bekdash Sr. Environmental Engineer dated 4/18/1996
 and 4/30/1996.

 New Jersey, (1995).  Regulations for Disinfection by Ultraviolet Light. New Jersey Register CITE 27
 N.J.R 4112. November 6, 1995.

 USEPA, (1995).  Restructuring Small Drinking Water Systems. Options and Case Studies.  Office of
 Water. Washington D.C. EPA 810-R-95-002.
UV Light Disinfection Technology in
Drinking Water Application—An Overview    449                     Final—September 1996
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                      CHAPTER 5.  SUMMARY OF FINDINGS
 This chapter summarizes the findings presented in the previous chapters. Sections 5.1,5.2, and 5.3 present
 the main findings of chapters 2 and 3. Section 5.4 presents the main findings of chapter 4.


 5.1     EFFICACY AND APPLICABILITY

 The initial summary of findings  presented below is based on the reviewed literature and information

 provided by non-governmental organizations and ultraviolet light manufacturers.  These findings are
 presented in more detail in section 2.5.


        •  Ultraviolet light (at a 253.7 nm wavelength) is effective against a wide range of pathogenic and
           nuisance microorganisms commonly found in ground water.

        •  The required inactivation dose of bacteria using ultraviolet light varies from one organism to
           another and within the  same species.

        • GeneraUy, the order of disinfection resistance is as follows:  bacteria (least resistant) < viruses
          < bacterial, spores < protozoan cysts and oocysts (most resistant).

        • Naturally, occurring microorganisms are more resistant to inactivation than-microorganisms
          cultured in laboratories.

        • Current contamination  indicator surrogate  microorganisms (total coliform  bacteria, fecal
          coliforms; EschericMa colt) are. more sensitive to disinfection by ultraviolet light than many
          identified pathogenic microorganisms (including viruses) that are of concern in drinking water.

        • Bacteriophage MS-2 inactivation data show that in a pilot study setting a 4 log reduction can
          be achieved by an ultraviolet light dose of 93 mWs/cm2.  Bacillus subtilis spores inactivation
          data show that in  a laboratory setting a 4 log reduction can be achieved using an ultraviolet
          light dose of 60 mWs/cm2.  A 60 mWs/cm2 dose  is sufficient to cause more than a 5 log
          reduction in  poliovirus.  A 50 mWs/cm2 dose is  sufficient to achieve 4 log reduction in
          rotavirus, which is more resistant to ultraviolet light than poliovirus and Hepatitis A virus.

        •  Two log reduction of Giardia lamblia is achieved at a dose of 180 mWs/cm2.  A minimum of
          3 log reduction of Cryptosporidium is achieved at a dose of about 8,750 mWs/cm2.

       .•  For water with a turbidity level of 5 NTU, 25 percent of the ultraviolet light  is absorbed by
        ',  turbidity-causing water constituents.
UV Light Disinfection Technology in
Drinking Water Application—An Overview     5-1                       Final—September 1996
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                                 Chapter 5—Summary of Findings
 Additional advantages of using ultraviolet light for disinfection are:        .


        •  Based on the current literature research, the use of ultraviolet light for water disinfection is not
           associated with the formation of known toxic or non-toxic conventional treatment by-products.
           If used for VOC destruction, no VOC  emissions result.

        •  Unlike chemical disinfectants, there  are no  known risks  associated  with over-sizing the
           disinfection chamber and there is no limit to the dose that could be applied in the disinfection
           process.  Overdesign of ultraviolet systems may be advantageous to cover transient periods
           during which surface water may contaminate a source.

        •  Ultraviolet light is successfully being applied in the field to mitigate contaminated ground water
           at Superfund sites. The literature search conducted for this report shows that even at low doses
           of ultraviolet light (doses'that are normally applied in POU commercially available devices)
           certain commonly used organic pesticides are slightly reduced.

        •  Ultraviolet light disinfection systems are very practical tools for upgrading and retrofitting small
           systems requiring small space with minimal or no construction work.

        •  Ultraviolet light disinfection systems require no storage of hazardous material.

        •  No onsite smell and no final water product smell.

        •  Very little residence time.

        • Taste is not altered (only improved) with the destruction of some organic contaminants  and
          nuisance microorganisms.                                                       .*••

        • Minerals in water are not affected.

        •  No or little (disposal of spent lamps or  obsolete equipment) impact on the environment  (some
          States require recycling of ultraviolet lamps).        -'


The Dutch waterworks guidance on the use of ultraviolet shows that if both the number of microorganisms

and AOC concentrations are low  (no  definite figure given), then post-disinfection can  be omitted

completely (ultraviolet light application fits  here  as an additional safety measure). In a typical  Dutch

waterworks, this occurs when multiple filtration steps (rapid filtration, GAC filtration, and slow sand filter)

are the final treatment steps. If the high concentrations of AOC are  present in the water, then regardless

of the number of microorganisms,  post-disinfection with a residual disinfectant is necessary.  If high

numbers of microorganisms and low concentrations of AOC are present in the water (this may happen

when GAC filtration is the final step in the treatment train), then disinfection to decrease the number of

microorganisms is needed. It is in this last situation where ultraviolet light technology, fits best for ground

water application (Kruithof et al., 1992).
UV Light Disinfection Technology in                  ,
Drinking Water Application—An Overview     5-2                        Final—September 1996
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                                  Chapter 5—Summary of Findings
  Therefore (according to the Dutch experience), the main parameter used to determine the applicability of
  ultraviolet light as a disinfectant instead of chemical disinfectants is the AOC level in the water before
  'the disinfection stage.                           '  .  '                 ,  '
                                                     are:
  Disadvantages of using ultraviolet light for disinfection

         • Lack of measurable disinfection residual.

         • Lack of an in-place standardized mechanism to measure and calibrate equipment efficiencv
           before and after installation.
         • Lack of a firm technical database on system efficacy in various water quality conditions.
         : Need for a secondary disinfectant for distribution network.        •

 5.2    OPERATIONAL FACTORS
 Closed ultraviolet light systems are recommended for drinking water applications rather than the open
 ultraviolet systems used in wastewater treatment.   The practical advantages of closed ultraviolet light
 systems, which are commonly used for drinking-water disinfection, are:

        • Minimal or no exposure hazards to workers as compared to open systems
   ,     • Very small space requirement; therefore, minimal or no construction costs
        • Simplicity  of installation  due to  modular design with two plumbing connections  and one
          electrical hook-up                                                  ,
        • Simplicity  of dismantling and replacing small units with larger units as population increases
          without the need for extensive construction
        • Lower maintenance requirements as  compared to open systems, .which are exposed to
          depositions from the air.                           ,

Ultraviolet light systems designed for small drinking water systems should consist of several modular units
to allow for a  continuous operation while one or two units are maintained.  For small ground water
systems, it is recommended that all electric fittings be of 'the modular type to facilitate installation,
replacement, and maintenance. All ultraviolet light systems should be equipped with monitoring devices
and before-and-after shut off valves.
UV Light Disinfection Technology in                                 ~"~"~	
Drinking Water Application-An Overview     5-3                       Final-September 1996
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                            Chapter 5—Summary of Findings
 5.3   EVALUATION AND COMPARISON OF ULTRAVIOLET LIGHT TECHNOLOGY
       COSTS TO OTHER DISINFECTION PROCESSES
 Capital costs for two ultraviolet light systems (one provides a dose of 40 mWs/cm2 and the other provides
 140 raWs/cm2) were compiled from three ultraviolet,light equipment manufacturers.  The average total
 costs are presented in Exhibit 5-1.  Exhibit 5-2 compares the costs of the ultraviolet systems at the two
 set doses to ozonatikra at 1 mg/1 and chlorination at 5 mg/1. Exhibit 5-3 compares the costs of ultraviolet
 systems that included chlorination as a secondary disinfectant at a dose of 1 mg/1 to ozonation at a dose
 of 1 mg/1 and chlorination at a dose of 5 mg/1.

       Exhibit 5-1. Average Total Costs for Ultraviolet  Light Disinfection Systems*
                                  Dose 40 mWs/cm2
EPA Row
Category
1
2
3
4
5
Design
Flow
(MGD)
0.024
0.087
0.27
0.65
1.8
Cost per Year (k$)
Total
Capital
1.3
. 1-7
3.7
7.7
16.6
Total O&M
0.4
0.8
1.7
3.7
9.7
Total
Production
Cost
1.7
2.5
5.3'
11.4
26.3
Cost per Year (c/kgal)
Total
Capital
14.8
5.2
3.7
3.2
2.5
Total
O&M
4.3
2.5
1.7
1.6'
1.5
Total
Production
Cost
19
8
5
• ;5 . •
,4
                                 Dose 140 mWs/cm2
EPA How
Category
1
2
3
4
5
Design
Flow
(MGD)
0.024
0.087
0.27
0.65
1.8
Cost per Year (k$)
Total
Capital
1.7
3.6
10.0
16.5
42.1
Total
O&M
0.8
2.1
5.5
9.4
34.0
Total
Production
Cost
2.5
5.7
15.5
25.8
76.0
Cost per Year (c/kgal)
Total
Capital
19.0
11.4
10.2
6.9
6.4
Total
O&M
9.0
6.5
5.6
4.0
5.2
Total
Production
Cost
28
18
16
11
12
"August 1995 dollars
UV Light Disinfection Technology in
Drinking Water Application—An Overview
5-4
Final—September 1996
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                               Chapter 5—Summary of Findings
  Exhibit 5-2. Comparison of Ultraviolet Light Disinfection Process Costs to Chlorination
               and Ozonation Process Costs in Cents per Thousand Gallons
USEPAFlow
Category \
1
2
3 ,
..-4
5
« •*»
Design *Ffow ,
~MGD*
0.024
0.087
0.27
0.65
1.8
- Ultraviolet
„ Dose
^mWs/cm2
19
8
5 V .
5
4
Chlorination '
~ ^Dose
' Smgfl
280
70
20
20 ,
10
Ozonation
..'Dose
-' 1 mgfl
350
100
30
20 -
10
Ultraviolet
". Dose
140 mWs/cm2
30
20
'20
10
10
     Exhibit 5-3.  Comparison of Total Production Costs of Ultraviolet Treatment with
              Secondary Disinfection to Chlorination and Ozonation Process
                            Costs* in Cents Per Thousand Gallons
USEPAFlow
Category
1
2
3
4
5
Design: Flow
(MGD)
- 0.024
0.087
0.27
0.65
1.8
40mWs/cm2
Ultraviolet
Dose with 1
mgfl chlorine
170
40
20
20
: 10
Chlorination
Dose 5 mg/I
280
70
20
20
10
Ozonation
Dose 1 mg/1
350
100
30
20
10
140mWs/cm2
Ultraviolet Dose
withlmg/l
chlorine
180
50
30
20
20
*Costs are rounded to the nearest ten.

As can be seen from Exhibit 5-2, ultraviolet light disinfection at the selected doses (without Chlorination
as a secondary disinfectant) is more economically feasible than ozonation and Chlorination for treating all
TJSEPA'flow categories  1 through 4;  and is more feasible than ozonation and Chlorination  at a 40
mWs/cm2 dose for the largest flow category. At 140 mWs/cm2, ultraviolet light treatment cost for flow
category 5 is more expensive but comparable to ozonation and Chlorination costs. As can be seen from
Exhibit 5-3, at the selected doses ultraviolet light technology  plus Chlorination is still economically as
feasible or more feasible than ozonation for flow categories 1  through 4, less feasible at 140 mWs/cm2
than ozonation for flow category 5, but has the same cost estimate as ozonation at 40 mWs/cm2 for flow
category  5.   Ultraviolet  light  disinfection at 40 ~mWs/cm2 plus Chlorination is  more feasible than
UV Light Disinfection Technology in
Drinking Water Application—An Overview
5-5
Final—September 1996
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                               Chapter 5—Summary of Findings
 chlorination alone for USEPA flow categories 1 and 2 and as feasible as chlorinatioh for USEPA flow
 categories 3 through 5. At a 140 mWs/cm2 dose plus chlorination, ultraviolet light is economically more
 feasible than chlorination for USEPA flow categories 1 and 2, less feasible for flow categories 3 and 5,
 and as feasible as chlorination as flow category 4.

 5.4    CASE STUDIES
 Satisfaction with ultraviolet treatment in water and wastewater applications has been expressed by the
 operators and systems managers contacted for this report. Ease and low cost of operation and maintenance
 were stated to be the major factors in selecting ultraviolet technology over chlorination.
UV Light Disinfection Technology in
Drinking Water Application—An Overview
5-6
Final—September 1996
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               APPENDIX A.  OTHER ULTRAVIOLET-RELATED
               DRINKING WATER DISINFECTION TECHNIQUES

 This appendix provides a brief description of nonconventional ultraviolet disinfection technologies. These
 technologies include photoassisted heterogenous catalytic oxidation (PHGO), and pulsed or modulated
 ultraviolet irradiation.

 The new ultraviolet manipulation techniques are either at experimental  stage or have  limited field
 applications. Both techniques seem to be very promising and warrant further investigation and investment
 in terms of research and development. At this point, both techniques lack a firm technical database for
 system design and feasibility (technical and economical). One technique manipulates the amplitude of
 ultraviolet light (pulsed ultraviolet light technique).  The other one uses ultraviolet light on a catalyst
 (TiO2), the water to  be treated (PHGO).                                       ~

 A.1 .  PHOTOASSISTED HETEROGENOUS CATALYTIC OXIDATION (PHCO)
 Purifies®, an ultraviolet light firm in Canada, uses a new ultraviolet light manipulation technique known
 as Photoassisted Heterogeneous Catalytic Oxidation (PHCO) to inactivate microorganisms and to destroy
 organic contaminants. This technique is being used successfully at many contaminated ground water sites
 (Purifies, 1995). PHCO is a process where photoactivated titanium dioxide (TiO2) is illuminated with near
 visible ultraviolet light in an oxygenated suspension.  The energy absorbed by titanium dioxide would
 produce a redox environment sufficient to mineralize organic compounds. The high oxidation reduction
 potential (ORP) levels achieved through this technique are also sufficient to inactivate microorganisms in
 water and wastewater.  The source of ultraviolet light could be either artificial or natural. TiO2 could be
 used in the form of TiO2-coated mesh or hi the form of powder suspended hi an aqueous solution.  The
 PHCO process has  been reported to be effective in degrading disinfection  by-products precursors
 compounds (Hand, Perram,  and Crittenden,  1995).   Also, the PHCO process has been  shown to
 successfully  degrade a wide variety of organic  contaminants, including drinking water regulated
 contaminants, such as polychlorinated biphenyls (PCBs) and polyaromatic  hydrocarbons (PAHs), into
 simple mineral acids, carbon dioxide, and water.  As mentioned above, the PHCO process has been
reported to inactivate microorganisms. However, one of the known drawbacks of the process is the lack
of a residual disinfectant after treatment. Richardson  et al.  1996 (unpublished study) investigated the
effects of using chlorination for residual disinfection on water treated with ultraviolet-activated TiO2.  The
UV Light Disinfection Technology in
Drinking Water Applications-Art Overview     A-l                      Final—September 1996
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 	Appendix A. Other Nonconventional Drinking Water Disinfection Techniques	
 research investigated the presence of by-products before and after chlorine treatment. As a result of the
 PHCO alone, the research identified one disinfection' by-product (tentatively identified as 3-methyl-2,4-
 hexanedione). When chlorine was used as a secondary disinfectant following the PHCO treatment, several
 chlorinated and bromrnated DBFs were formed.  Most of these DBFs (although less in number and lower
 in concentration than DBFs resulting from chlorination only) were the same as those DBFs identified when
 chlorine was used alone for disinfection (Richardson et al., 1996).

 Wei et al., 1994, and Ireland  et al., 1993,'investigated the  inactivation of Escherichia coli by TiO2
 photocatalytic oxidation.  The researchers concluded that  the PHCO process is effective  against
 Escherichia coli and reported 100 percent destruction at a TiO2 catalyst dose of 1 g/L and a contact time
 of 30 minutes.  The researchers cautioned that although the results may be exciting,  any optimism must
 be tempered by the fact that Escherichia coli and other traditional surrogate microorganisms are rather
 "easy" targets for disinfection by ultraviolet disinfection techniques. The real challenge would involve
 demonstration of the efficacy of TiO2 in inactivating  recalcitrant pathogenic microorganisms  such as
 Giardia lamblia and Cryptosporidium parvum (Wei et al., 1994).
                                                                                      /

 Hand,  Perram, and  Crittenden, 1995, demonstrated in a laboratory  setting that PHCO degrades DBF
 precursors using an .artificial ultraviolet light source or sunlight. A minimum of 66 percent of the Total'
 THM Formation Potential  (TTHMFP)  were destroyed (contact time 30  minutes).  Hand et al., 1995,
 provided information on PHCO process cost estimates using artificial light and sunlight as a source for
 TiO2 illumination. The Hand et al. cost estimates for treating 1 MOD are presented  in Exhibit A-l.
         Exhibit A-l. Cost Estimates for the Removal of DBF Precursors from 1 MGD
                         Using the PHCO Process (Hand et al., 1995)
Contact Time
(min)
Artificial Light
15
30
45
60
Sunlight
Capital Costs
(K$)

75.3
117
143 ,
176.7
1,082
• Annualized
Capital Cost (K$)

8.844
13.750
16.800
20.800
127
Annual
Operation and
Maintenance (K$)

109
193
267
346
49
Total Production
Cost(e7Kgal)

32
57
75
100
48
UV Light Disinfection Technology in
Drinking Water Application—An Overview
A-2
Final—September 1996
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           Appendix A.  Other Nonconventional Drinking Water Disinfection Techniques
 Exhibit A-l shows that the operation and maintenance cost of sunlight-activated PHCO process is about
 56 percent of the total annual cost of treatment; the operation and maintenance cost of artificial light is
 about 97 percent of the total annual cost of treatment.  Hand et al., 1995, reported that electricity costs
 alone account for 80 percent of the total annual cost of treatment in systems using artificial ultraviolet
 lights.                                                       .

 Hand et al. (1991), as reported in USEPA (1992) at 4-41, gave the following advantages:

        • Removal of non-purgeable organic carbon (NPOC) and disinfection  by-products (DBF)
          precursors                 ..  •                                     . ' •
        • Reduction in biodegradable fraction of NPOC
        • Lower disinfection dosage, compared to the use  of direct ultraviolet light
        • Mineralization of trace organics such as pesticides, hydrocarbons, chlorinated hydrocarbons, and
          taste and color compounds     -
        •  Inactivation of pathogenic microbes
        •  Sunlight or near-ultraviolet light will activate the catalyst.

 Disadvantages:
        »  Uncertainties in cost (no information is available at this point)
        •  Lack of a firm technical database for system design.
                                                                                         \
 A.2    INACTIVATION RATES ACHIEVED WITH  THE USE OF MODULATED
        ULTRAVIOLET LIGHT
 Bank et al. (1990) studied the effectiveness of computer-controlled modulated ultraviolet-C (200 nm to
 280 nm) hi a series  of in vitro experiments.  The low-intensity pulsed1 lamp (< 0.04-mW/cm2 at 8 cm
 distance) was used to irradiate 5 strains of bacteria. The exposure time was 60 seconds, which implies .
 an ultraviolet light dose of about 2,5 mWs/cm2 at 8 cm  distance  using the pulsed lamp.  Bacteria were
 irradiated  with modulated ultraviolet light for 60 seconds at 31 cm, which indicates -a  dose that is
 considerably less than 2.5 mWs/cm2.  The bactericidal effect was almost the same for Escherichia coli
ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa  ATCC 27853, Serratia
   'In pulsed energy techniques, power (energy/time) is magnified many times by means of a capacitor. A capacitor stores
the electric energy and then releases it rapidly all together.  This allows power to be amplified using average power
consumption.                                   .                          -  .     -           •

UV Light Disinfection Technology in
Drinking Water Application—An Overview    A-3                       Final—September 1996
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 	Appendix A. Other Nonconventional Prinking Water Disinfection Techniques 	.
 marcesceus ATCC 8100, and Staphylococcus epidermidis VAS 9, with 6 to 7 log reduction in the number
 of viable  bacteria.  When bacteria were irradiated with non-modulated ultraviolet light at the same
 intensity and distance,  the number of colonies surviving the treatment was more than 100 times the
 number of colonies surviving the modulated treatment.  The energy requirements and costs of this new
 technique are considerably less than those of the traditional ultraviolet systems required to meet same log
 reduction; however, the capital costs are unknown and the applications are still in the experimental stage.

 Dunn,  Ott, and Clark (1995) reported  a  6  to  7 log reduction  of  both Klebsiella terrigena and
 Cryptosporidium parviim ooqysts, using pulsed ultraviolet light at a dose of 1000 mWs/cm2.  The dose
 is delivered in one flash. The source of Cryptosporidium parvum oocysts was infected mouse feces.  The
 same results were achieved by two pulsed-light flashes at a dose of 500 mWs/cm2 each.

 For surface applications (food, equipment, etc., disinfection), Dunn, Ott, and Clark ,(1995) reported that
 the cost of apulsed-ultraviolet light system capable of delivering 4,000 mWs/cm2 is less than a few tenths
 of a cent per square foot of treated area.  This conservative cost estimate includes equipment amortization,
 lamp replacement, electricity, and maintenance (Dunn, Ott, and Clark, 1995).

 A.3    REFERENCES
 Bank,  H.L., et al. (1990).   "Bactericidal Effectiveness  of Modulated UV  Light."   'Applied  and
 Environmental Microbiology.  Vol. 56, No. 12, pp. 3888-3889.                            "
 Dunn,  Ott, and Clark (1995). "Pulsed-Light Treatment  of Food and Packaging." Food  Technology,
 September,  pp. 95-98.
 Ireland, et al. (1993).  "Inactivation of Escherichia coli by Titanium Dioxide Photocatalytic Oxidation."
Applied and Environmental Microbiology. Vol. 59, No. 5, pp. 1668-.
 Purifies (1995).  Personal communication with Mr. Brian Gutters  and Mr. Tony  Powell.
Richardson, et al. (1996).  "Identification of TiO2/UV By-Products in Drinking Water," draft paper of
research conducted by the USEPA Ecosystems Research Division, National Exposure Research Laboratory,
Athens, Georgia, and the USEPA Drinking Water Research Division, National Risk Management Research
Laboratory, Cincinnati, Ohio.  13 pages, 29 references, 5 figures,  and 2 tables.
                                                                          it
USEPA (1992).  Technologies and Costs for Control of Disinfection By-Products (Draft).  Science and
Technology Branch, Criteria and Standards Division, OGWDW. Malcolm Pimie, Inc.
Wei, et al. (1994).  "Bactericidal Activity of TiO2 Photocatalyst in Aqueous Media:  Toward a Solar
Assisted Water Disinfection System."  Environmental Science and Technology.  Vol. 28, pp. 934-.
UV Light Disinfection Technology in
Drinking Water Application—An Overview     A-4                       Final—September 1996
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                      APPENDIX B.  ORGANICS DESTRUCTION
                     ""•^""^•••••••••^••••"••^"••^"•^^••^^^•••••••^^••^^••l
   B.     INTRODUCTION
   This appendix provides a brief description of the theoretical scientific foundation that explains the potential
   destruction capabilities of ultraviolet light against organic-compounds. It presents current findings from
   a literature search and information provided by ultraviolet light equipment manufacturers.  Appendix B
   also describes the analysis' of ultraviolet light technology potentials for the destruction of volatile organic
   compounds and other priority organics that might be found in drinking water sources.

   B.1     BACKGROUND
   Molecules  absorb specific wavelengths (range) of electromagnetic radiation.  The most useful region of
   the ultraviolet spectrum for transferring energy to a molecule is at wavelengths greater than 200 nm.
   When a molecule, absorbs ultraviolet radiation, the energy level in the bonds  of that molecule increases.
   The absorption of ultraviolet radiation also  results in an increase hi the  orbiting level of the excited
   electron or electrons hi higher energy orbitals (Fessenden and Fessenden, 1986).  In general, molecules
   that require more energy for electron promotion absorb photons at shorter wavelengths and molecules that
   require less energy absorb photons at longer wavelengths.                         ;

   As a practical electromagnetic energy form, ultraviolet light has  been employed in many chemical
   manufacturing processes. A classical example of the use of ultraviolet light to form chemical compounds
   is  the production process of the widely used solvent, carbon tetrachloride (CG1J (Giancoli,;i991).
   Ultraviolet light energy is used td break the C-H bonds hi natural methane gas (CH^ hi the presence of
'   chlorine molecules (C12):                    ;

                                  , CH4 + 2CLJ hv  CC14 + 2H,
  At a wavelength of 254 nm, organic compounds with double conjugated bonds like the C=C bond absorb
  ultraviolet radiation. The presence of pesticides and other organic contaminants hi varying amounts in
  ground water sources raises the issue of the efficacy of ultraviolet light for destroying organic compounds
  found in ground water and of the possibility of harmful by-product formation.
  UV Light Disinfection Technology in
  Drinking Water Application—An Overview     B-l                       Final—September 1996
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                              Appendix B. Organics Destruction
The scientific literature contains sufficient evidence that ultraviolet light, alone and in combination with
03 and H2O2, is a viable tool in degrading toxic and nuisance organic compounds that occur in ground
water. However, the efficacy of ultraviolet light at doses typically applied in household treatment devices
to destroy organic compounds has not been studied by many researchers.

B.2  DESTRUCTION POTENTIAL
The effects of ultraviolet light on organic compounds are well known.  The formation of ozone and
hydrogen peroxide from the action of ultraviolet light on drinking water is one of two mechanisms that
lead to the disinfection of microorganisms and destruction of organic compounds. The other mechanism
is the direct action of ultraviolet light on the bonds connecting the atoms in organic compounds, thus
destroying the fundamental building blocks in an organic compound or microorganism.  In contaminated
ground water, the use of ozone and hydrogen peroxide in combination with ultraviolet light hastens the
oxidation process and, hence, the destruction of both microorganisms and organic contaminants.

The destruction potential of organic compounds using ultraviolet light  can be explained through
understanding the chemical bonding processes and the effect of electromagnetic energy on the electrons
engaged in bonding processes.  The figures and illustrations presented within Exhibit B-l are intended
to be used as theoretical background information and are not intended to be used as exact figures or for
interpolation for direct field application.
                                                                                 t
Ultraviolet light is  a viable technology for destroying  organic contaminants in drinking water sources,
however, cost may be an  obstacle. For example, the equipment manufactured to destroy high levels of
organic  contamination in ground water Superfund sites is designed to produce ultraviolet light at
significantly higher doses and intensities than those needed for conventional drinking water treatment
purposes.  Therefore,  the power costs required to operate equipment specifically intended for  organic
destruction are high.                                ''•'•:*
UV Light Disinfection Technology in
Drinking Water Application—An Overview     B-2                       Final—September 1996
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                                Appendix B.  Organics Destruction
              Exhibit B-1. A Precis Description of Chemical Bonding to Explain
                    Organics Destruction Potential Using Ultraviolet Light
    A coyaient bond results from the sharing of a pair of electrons by two atoms,  m a covalent bond,
    the molecular orbital that is symmetrical about its axis is called a sigma (a) molecular orbital and
    the covalent bond is a sigma bond. An example of a cr bond is a C-H bond in a methane molecule.

    The energy from ultraviolet light pushes  the pair of electrons into a higher orbital level, causing the
    electrons to become out-of-phase (in wave function). This is called an antibonding orbital and is
    given the symbol a*.                                            -

    The figure below shows a two-dimensional schematic presentation of electrons in orbital motion.
    Closer to reality representation is far more complex and beyond the scope of this report. The
    important aspect of this presentation is that it shows that when two electrons are in phase forming
    a bond, .both electrons do move together above and below the axial plane.  The positive  and
    negative signs'in the figure are used to indicate the presence of electrons above the plane or below
    the plane and are not an indication of charge or anything else.

                       Electrons in in Phase and out of Phase Wavelengths
                                               or
                                     In Phase Electrons
                                               or
                                        Out of Phase
                                                                                 022E-06
   A covalent Pi (TC) bond is a molecular orbital bonding joining two atoms and is located above and
   below the plane of sigma bond. An example of this bond would be the double bond in ethylene
   H2C = GH2 where the first C-C bond is the a bond and the second C-C bond is the 7t bond.  When
   a TC  bond is  unexcited, the, electrons are in phase.  When ultraviolet light is absorbed by the
   molecule, the electrons become out of phase and the antibonding orbital is called K* (McMurrv
  - 1992).                                                                          .      J'

   Because all organic contaminants have a and n bonds, the transition of TC and o electrons into an
   antibonding state is a very important step in the destruction of organic contaminants hi drinking
   water. Many of the slow or non-biodegradable organic contaminants found in ground water have
   ring  molecules like benzene, pyridine, and furan compounds.  Ultraviolet light is very effective in
   breaking up rings and making these compounds more prone to undergo mineralization or become
   more biodegradable.        .

   Also important in the understanding of molecular destruction through ultraviolet light is the role of
   nonbonded electrons.  These  are pairs of electrons (called the (i\) pair  of electrons) that fill a
   molecular orbital,  but were not formed by a bond.

   An example of (T|) electrons is the electron pairs of an oxygen atom in methyl alcohol CH3OH..
UV Light Disinfection Technology in
Drinking Water Application—An Overview
B-3
Final—September 1996
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                               Appendix B. Organics Destruction
             Exhibit B-1. A Precis Description of Chemical Bonding to Explain
             Organics Destruction Potential Using Ultraviolet Light (Continued)
    When ultraviolet light is absorbed by such a molecule, the orbital containing (TJ) electrons does not
    have an antibonding orbital like 
-------
                           Appendix B. Organics Destruction
            Exhibit B-1. A Precis Description of Chemical Bonding to Explain
            Organics Destruction Potential Using Ultraviolet Light (Continued)
              Cl
              j
          H-C-CI
              I
              Cl
         Trichloromethane (Chloroform)
                        Examples of Photochemical Reactions
 Cl
           \
                  Cl
                  \
         Cl        H
         Trichioroethene
         Cl

         p-Dichlorobiphenyl
                Os/hv
                 H2O
                 Os/hv
                 H20
                           HO     OH
                            Oxalic Acid
                   hv
        HCOOH
        Formic Acid
            o
             II     +hv
        CHsCCHs
        Acetone
                  CO2 + H2O
                              -C^O  +  CH3
                              I  OH-      10H-
                          CHgCOOH   CH3OH
                                    Methyl Alcohol (Methanol)
                               Acetic Acid
CHsCOOH
Acetic Acid
                                                       OH-   COOH
                    OH-
                     hv
                           COOH     hv   COOH
                   CO2 + H2O
                                                    .  GOOH
                                                    Oxalic Acid
                                                            022E-07
UV Light Disinfection Technology in
Drinking Water Application—An Overview
                              B-5
                                                            Final—September 1996
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                               Appendix B.  Organics Destruction
 The destruction of an organic compound by ultraviolet light is given in the following example:

 Trichloroethylene (TCE) is a contaminant found in many ground water sources in the United States.
                              C  = C   + hv  — >• CO2 + HjO + 3C1
Ultraviolet light absorbed by dissolved oxygen and water molecules ultimately leads to the formation of
unstable radicals such as hydroxyl radicals. These radicals react with excited TCE molecules and break
them up, leading to the formation of the innocuous final product of water and carbon dioxide.

To effectively control organic compounds in water and wastewater using ultraviolet light, three approaches
can be followed:
1.     Determine the optimal absorption wavelength of the target compound, and order the hardware that
       can deliver ultraviolet light at that wavelength.  The absorption  spectra of many  organic
       compounds are available in the literature.
2.     Use ultraviolet-light to produce compounds that can attack the target compound.  For example,
       ultraviolet light at 184.9 nm attacks water molecules to produce H" and OH" radicals that are
       powerful oxidizing agents.
3.     Increase the oxidizing power available by adding oxidizing agents such as ozone and hydrogen
       peroxide and then irradiate the water.  The use of ultraviolet light not  only will produce free
       radicals as in approach number 2 but also will excite the added ozone and hydrogen peroxide, thus
       increasing their already powerful oxidizing power.

It must also be noted that  the oxidation  potential of ultraviolet-produced radicals in drinking water
compared to those of chlorine gas and ozone (in volts) is in the following order (Jody, Klein, and Judeikis,
1989):                                                  .         ,             .
                      OHT  >  O-   >  03   >  H02*  >  C12
                      2.80     2.42     2.07     1.70       1.36     in volts ,
The literature search conducted for this report resulted in the following findings regarding the destructive
potential of organics using ultraviolet light. Nick et al. (1992) studied the degradation of selected triazine
herbicides by ultraviolet light as used in the ultraviolet disinfection of drinking water. Triazine herbicides
are a family of herbicides that include simazine and atrazine. Atrazine is a commonly used herbicide in
UV Light Disinfection Technology in
Drinking Water Application—An Overview     B-6   .               •      Final—September 1996
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                                Appendix B.  Organics Destruction
  corn cultivation  and is  found in many ground water sources.  In their research, Nick  et al.  (1992)
  addressed two issues:

         • The extent  to which ultraviolet photolysis  of herbicides  gives rise to  new anthropogenic
           compounds  that are as, or more, dangerous than the original compounds
         • The extent to which herbicides degrade during normal ultraviolet application to drinking water.

 Nick et al. (1992) noticed that many herbicides do not absorb ultraviolet light above 240 nm and that only
 those herbicides that contain an aromatic ring or similar chromophore may degrade at wavelengths above
 240 nm. Using an ultraviolet lamp of an average dose of 25 mWs/cm2, Nick et at (1992) concluded that
 the degradation of triazine herbicides remains below 5 percent.  Nick et al. (1992) also reported that a
 conversion  of more  than 10 percent  of  atrazine,  simazine,  propazine;  and  terbuthylazine by
 photodegradation  did not result in mutagenicity (using the Ames test),  even when the irradiated material
 was applied in high concentrations.  Therefore, ultraviolet photolysis of triazine herbicides  did not give
 rise to  new equally or  more hazardous compounds,  mtraviolet photolysis of triazine compounds does
 eliminate the mutagenicity risks associated with the triazine compounds. Treatment of drinking water for.
 disinfection by commercially available POU ultraviolet lamps, even at doses as low as 25 mWs/cm2, has
 a positive side effect. The Nick et al. (1992) research shows a herbicide degradation of less than 5 percent
 for four triazine compounds.

 Exhibit B-2 presents the photodegradation of herbicides of the atrazine family as reported by Nick et al.
 (1992).              '                       .'       '                              .   .-.

            Exhibit  B-2. Photodegradation of Herbicides of the Atrazine Family
Herbicide
Atrazine
Simazine
Propazine
Terbuthylazine .
Fraction Decomposed at
25mWs/cm2(%)
2.4
3.4
4.1
4.4
Dose Required to Achieve 90%
Decomposition (mWs/cm2)
2400
2700
1400
1300
As can be seen from Exhibit B-2, the dose required to degrade 90 percent of the initial herbicide
concentration in the solution is about two orders of magnitude higher than the  dose emitted by most
commercially available ultraviolet devices used for disinfection purposes.
UV Light Disinfection Technology in
Drinking Water Application—An Overview
B-7
                          Final—September 1996
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                               Appendix B. Organics Destruction
 Francis (1989) studied the physio-chemical parameters of oxidating organic pollutants using ultraviolet
 light and ozone.  Using ethylene glycol as a surrogate and a 2 kw antimony halide medium-pressure lamp,
 Francis (1989) concluded that using ultraviolet light after saturating the flow with ozone increased the
 reduction rate of TOC. Francis (1989) made another important observation. He. observed that a smaller
 reactor in series with a larger reactor leads to an increase in TOC reduction.  Francis (1989) attributed this
 increase in TOC reduction to the improved uniformity of the ultraviolet light distribution in the smaller
 reactor.

 Berglind, Gjessing, and Johansen (1979) studied the effects of ultraviolet light in combination with H2O2
 on aquatic humus and organic compounds. The early results compiled by the researchers showed that,
 after one minute of irradiating hydrogen peroxide containing water, a 45 percent reduction in color and
 a 43 percent reduction hi organic carbon were achieved. The researchers also reported their own research
 on water containing humus and, 65 ug/1 of the contaminant 3,4-benzo(a)pyrene [B(a)P] (a polyaromatic
 hydrocarbon [PAH] compound, which is a contaminant regulated under the National Primary Drinking
 Water Regulations [NPDWR]), 1 ug/I 2-methylisoborneol (MB), 100 ug/1 of chloroform, and  100  ug/1
 of bromodichloromethane (BDCM).  The results of the researchers' experiments are presented in Exhibit
 B-3.  The ultraviolet radiation unit consisted of six 30-watt ultraviolet lamps; however, the intensity was
 not reported in the published paper.

 As can be seen from Exhibit B-3, after 2 hours of irradiation without hydrogen peroxide, 29 percent of
 B(a)P was destroyed and 91 percent was destroyed in the presence of hydrogen peroxide.

 The results for chloroform and BDCM were better, with 58 percent and 91 percent reduction in chloroform
 and 25  percent and 91  percent reduction in BDCM without and with the addition of 0.1 ml 35-percent
 hydrogen peroxide in a 0,8 liter reactor.                                      .

 Xu et al. (1989), using ozone and ultraviolet light, examined TOC reduction in wastewater under different
 pH conditions. Xu et al. (1989) used the compound pyridine as a surrogate for refractory compounds
 commonly found in industrial wastewater.  The Xu et al.  (1989) research shows that at high pH, better
 TOC reductions could be attained.  The  research also suggests that the breakup of pyridine molecules
 occurs in stages where the ozone breaks the ring molecule, leading the way to more oxidative intermediary
UV UgM Disinfection Technology in
Drinking Water Application—An Overview     B-8                       Final—September 1996
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                               Appendix B.  Organics Destruction
     Exhibit B-3.  Removal of Organic Chemicals from Water with Ultraviolet Radiation
                                   and Hydrogen Peroxide
ug/l (percent destruction)
'
Minutes UV
Radiation
0
30
.60
120
' 240
Without H2Q2
B(a)P
65(0)
-
-
42 (29)
-
Chloroform
100(0)

92 (8) '
42 (58)
-
BDCM
100(0)
-
91 (9)
75 (25)
-
With 0.1 ml-35%H.,O,/l
B(a)P
'- - •
-
18 (72)
6(91)
1 (98)
MIB
1
0 (100)
—
.—
-.
Chloroform
100 (0)
75 (25)
68 (32)
9(91)
-
BDCM
100(0)
58 (42)
44(56)
9 (91)
—
  B(a)P:  3,4-Benzo(a)pyrene
  MIB:   Methylisoborneol
  BDCM:' Bromodichloromethane
  ():     Denotes percent-reduction
                                       B(a)
                                         Percent reduction of chemicals in aqueous solutions with
                                         different "UV doses"; 0.1  ml 35% \^QJ\ was added.
                                         MIB = Methylisoborneol
                                         BDCM = Bromodichloromethane
                                         B(a)P = 3,4 Benzo(a)pyrene
          30  60
                      120             240

                   Minutes UV - Radiation
    022E-01
 compounds.  Once all pyridine molecules are destroyed, a fast degradation of TOC occurs as the newly

 formed intermediary compounds quickly mineralize (i.e., breaking organic compounds down to inorganic

 compounds such as CO2 and H2O). Xu et al. (1989) found that pH 10.3 to be the optimal.pH.  The results

 of the Xu et al. (1989) work are presented in Exhibits A-4 and A-5.



 Exhibit B-4 shows that the breakup rate of pyridine in an ozone/ultraviolet system was faster than the TOC

'reduction rate  in the  same system and  under the  same  conditions.   This  implies  that complete

 mineralization of pyridine is not direct and that intermediary organic compounds are formed in the process.

 Exhibit B-4 also shows that a combined ozone/ultraviolet system is more effective in destroying pyridine

 and reducing TOC than an ozone  system alone.
 UV. Light Disinfection Technology in
 Drinking Water Application—An Overview
B-9
Final—September 1996
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                            Appendix B.  Organics Destruction
   Exhibit B-4.  Elimination of Pyridine and TOC Reduction by O3/UV and Ozone Alone
               100
            
           CC   50
           6
                25
                                                   Og/UV
                            60
                                               240
                   120       180
                  Time (Minutes)

b. Percent reduction of pyridine TOC by Og/UV and O3 alone
                                                           022E-03
                                                        T=40°C
                                                        pH=10.5
                                                        O3=11mg/I
                                                        UV=50w
                                                        T=40°C
                                                        pH=10.5
                                                        O3=11mg/l
                                                        UV=50w
UV Light Disinfection Technology in
Drinking Water Application—An Overview
                              B-10
                                               Final—September 1996
-------
                              Appendix B. Organics Destruction
           Exhibit B-5. Pyridine Elimination and TOC Reduction at Different pHs
                           60             120
                                 Time (Minutes)

             a. Percent elimination of pyridine at different pHs
180 -
022E-04
         too -
     o
     e.
                          60            120           180
                                Time (Minutes)
            b. TOC reduction at different pHs
                                                                      1. pH=2.1
                                                                      2. pH=12
                                                                      3. pH=7.8
                                                                      4. pH=10.5

                                                                      T=40°C, UV=50W
                                                                      O3 at 10,7-10.8 mg/l
                                                                      initial concentration
                                                                      of pyridine 194ppm
              1. pH=2.1
              2. pH=12
              3. pH=3.5
              4. pH=7.8
              5. pH=10.5

              T=40°C, UV=50W
              O3 at 10.7-10.8 mg/l
              initial concentration
              of pyridine 194ppm
UV Light Disinfection Technology in
Drinking Water Application—An Overview     B-ll
             Final—September 1996
-------
                                Appendix B.  Organics Destruction
 Exhibit B-5 shows that at low pH, pyridine destruction rate and TOC reduction rates are the lowest.  The
 highest pyridine destruction rate and TOC reduction rate occurred at a pH of 10.5.

 Yu, Wan, and Tsai (1989) compared TOC removal from activated sludge using oxygen/ultraviolet systems
 versus ozonation as pretreatment. The researchers found that in activated sludge, pretreatment with ozone
 had a better effect on the biodegradability of phenolic compounds than the O2/UV system. The researchers
 did not report any ultraviolet doses in their published paper.

 Zeff, Leitis, and Barich (1989) used ultraviolet/ozone and ultraviolet/H2O2 systems to control an array of
 contaminants usually found  in ground  water at  Superfund sites.   The researchers  reported  that
 tetrachloroethylene or perchloroethylene (PCE) contaminated water treated with these systems resulted in
                                                                                   \
 the  reduction  of VOCs  and  color  to  below  State  action  level.    They  also  reported  that
 dibromochloropropane  (DBGP)  and PCBs were reduced to less than 1 ppb.  Both contaminants are
 regulated under NPDWR with an MCL of 0.002 mg/1 for DBCP and an MCL -of 0.0005 mg/1 for PCBs.
 The researchers reported direct operation and maintenance costs associated with treating PCE-contaminated
* drinking ground water of 200 ppb as being $0.20 to $0.30 per 1,000 gallon (1989 prices).

 Jody, Klein, and Judeikis (1989), using ozone/ultraviolet systems to treat wastewater containing hydrazine
 compounds, found that the presence of metal ions  such as copper and iron help in the destruction of
 hydrazine compounds. The researchers also confirmed the findings of Xu et al. (1989) that the destruction
 of organic compounds is more efficient at high pH.  The researchers did not report any, ultraviolet doses
 in their published paper.  More research on the effects of metal ions on  the destruction of organic
 contaminants is needed to elucidate the processes involved and determine the kinetics of the destruction
 process.    '                   •

 In a more recent study of Ultrox®, Zeff (1993) reported the results of using an ozone/hydrogen peroxide/
 ultraviolet system to remove PCE from a contaminated ground water well. The results are presented in
 Exhibit B-6. As can be seen from Exhibit B-6, the system tested is capable of reducing PCE levels to
 below MCL levels and 1,1,2-trichloroethane (TCA) levels in two tests. However, the author did not report
 any specific ultraviolet doses.                       .
 UV Light Disinfection Technology in
 Drinking Water Application—An Overview    B-12                      Final—September 1996
-------
                               Appendix B. Organics Destruction
        Exhibit B-6. Uitrox® Demonstration at South Gate Ground Water Supply Site
' ,
Test No.
1
2
3
4
5
6
7
8
9
10
11
12 '

O3 Dose
(rrig/|)
13
19 '
19
0
0
0
13
0
o
9
13
9
Pilot Test Procedures and Analytical Results*
(all tests run at 50 gpm)
H2O2 Dose
(mg/l)
None
None
8.3
13
8.3
0
8
8.3
8.3
4
0
0
UVLamp
Complement
Full
Full
None
None v
One Third
Full
None
One Fourth
One Half
None
None
None
PCE Analysis
Infl.HjQ
(PPb)
14
20
17
17
17
17.5
18
16
J6
18
-
18
Effl.H.,0
-------
                              Appendix B. Organics Destruction
    Exhibit B-7. Chlorinated Hydrocarbon Elimination with Ozone/Ultraviolet Treatment
                        'in Drinking Water Supply of Niederrohrdorf
Parameter
1 ,1 -Dichloroethylene
cis-1 ,2k-DichIoroethylene
Chloroform
1 , 1 -Dichloropropene
Trichloroethylene
Perchloroethylene
Sample A (ng/I)
Before
After
Ozone/UV-Treatment
<0.05
31
0.12
0.12
100
0.12
0.12
0.37
<0.05
<0.05
5.9
<0.05
Sample B (pg/l)
Before
After
Ozone/UV-Treatment
n.a.
16
<0.05
n.a.
84
n.a.
n.a.
0.06
•0.1
n.a.
5.3
n.a.
 Gehringer et al. (1993) investigated the feasibility of using an ozone/ultraviolet system to treat TCE- and
 PCE-contaminated water in a real situation compared to an ozone/electron beam system. The researchers
 found that the destruction of organic compounds using an O3/electron beam system was about one order
 of magnitude higher than the destruction obtained using the ozone/ultraviolet system.  Moreover, the
 researchers found that the electric power consumption in an ozone/electron beam accelerator system was
 five times less than that of an ozone/ultraviolet system.  The ultraviolet lamp used in the experiment had
 an output of 7.8 kw and the electron beam output was a 500 keV electron accelerator, or 8xlO~14 Joules.1

 In 1994, the Journal of Hazardous Waste Consultants  compared the use of ultraviolet systems for the
 destruction of VOCs  with other technologies and noted that ultraviolet systems destroy VOCs found in
 drinking water, while air stripping systems, for example, transfer the VOC contamination from the liquid
 phase to the gas phase (JHWC, 1994).           .                                      i

 B.4    OPERATIONAL FACTORS                                           ,  V
 Operational factors that should be considered for maximizing the effectiveness of ultraviolet systems for
 the destruction of organic contaminants are the following:
       • Proper selection of an ultraviolet lamp that emits the proper effective wavelength range and .that
         delivers the required dose.
       • Age of the lamps.
   'KeV « 1.6 x 10-'s Joules
    1 Watt = 1 Joule/sec
UV Light Disinfection Technology in
Drinking Water Application—An Overview
B-14
Final—September 1996
-------
                                  Appendix B.  Organics Destruction
           • Keeping track of lamp efficiency, particularly when lamps are at the end of their operational
             life span.
           • Cleaning the unit periodically as recommended in the manufacturer's manual, regardless of
             whether the unit looks clean-to the naked eye.
           • Waters that contain light-obstructing material, such as colloids or certain minerals such as iron,
             need to be treated before entering the ultraviolet unit.
           • Keeping a record of influent and effluent quality parameters such as pH and ORP (oxidation
             reduction potential) to monitor any sudden changes that require immediate attention.

   The following  section  discusses factors related  to ultraviolet wavelength transmission and  presents
   intensities required to destroy certain chemical bonds normally found in organic contaminants.  Other
   operational factors are discussed hi more detail in Chapter 2.                  .

   The graphical presentation for the distribution of wavelengths emitted by low- and medium-pressure arcs
   given in (Exhibit 1-3) was constructed from a paper published by Legan in 1982.  As can be seen from
   Exhibit 1-3 and Exhibit B-8, for that specific low-pressure lamp, about 93 percent of ultraviolet light is
,   transmitted at 254  nm and 6 percent is transmitted at 185 nm.

   The distribution of wavelengths emitted by modern low-pressure arcs used in water application varies but
   is assumed to be at a minimum about 85 percent of the energy at 254 nm (range 85% - 90%), 7-10
   percent of the emitted energy in the 180 to. 185 nm range, and 5 percent at more than 254 nm (von
   Sonntag and  Schuchman,  1992).  This spectrum  of ultraviolet light range increases the likelihood of
   ultraviolet absorption by different molecules. As stated earlier, molecules absorb ultraviolet energy at
   specific wavelengths and not at all wavelengths. For example, benzene absorbs ultraviolet light at 260
   nm. Thus, when a  low-pressure ultraviolet light is used for disinfection of drinking water, a contaminant
   that -absorbs  a wavelength other than 254 nm wavelength will  absorb  the specific  wavelength that
   constitutes a small  fraction of the light emitted by the ultraviolet lamp.   "

   There are medium-pressure and high-pressure arc lamps that are capable of producing a broader spectrum
   of the ultraviolet range,  and  there are high-pressure  arc lamps that produce the bulk of their ultraviolet
   light at a higher energy wavelength (180 to 185  nm).  These high-energy (shorter)2  wavelengths  are
   Intensity is defined as the power transferred across a unit area, where:
   Power = Work/time = Energy transferred/time, where Energy is inversely proportional to wavelength.
   For further details, please refer to page vii.

   UV Light Disinfection Technology in
   Drinking Water Application—An Overview    B-15                        Final—September 1996
-------
                               Appendix B. Organics Destruction
 capable of producing unstable radicals that in turn attack other organic compounds found in the water.
 This is an important mechanism in which contaminants that do not absorb the ultraviolet light emitted
 energy, or only a small portion of it, get destroyed by intermediaries formed by ultraviolet light action.

 Exhibits A-9 and A-10 (presented below) are intended to give an idea of the destruction potential of
 ultraviolet light against various organic and inorganic compounds. The maximum wavelengths (lowest
 energy) needed to break a bond (a or TC) varies from one compound, to the other. This variation in energy
 requirements to break an organic compound also can be found in the range of wavelengths that could be
 absorbed in certain compounds. For example, for aromatic compounds, intense ultraviolet light absorption
 occurs at 205 nm, while weak ultraviolet light absorption occurs at 260 nm (McMurry, 1992).
       •
 The power of various wavelengths emitted by different ultraviolet lamps are presented in Exhibit B-8.
 Exhibit 2-8 shows that the wavelengths emitted by ultraviolet light vary from one pressure lamp to  the
 other. As can be seen from Exhibit B-8, low-pressure arc lamps emit the bulk of their energies at about
 254 nm wavelength, while medium- and high-pressure lamps emit their energies at a wider range. The
 germicidal effects of ultraviolet light at 254 nm are high.  Because of that, when ultraviolet light is to be
 used for disinfection, low-pressure mercury lamps are selected over medium- and high-pressure mercury
 lamps.

 Exhibit  B-9  presents the maximum light wavelengths (minimum energies) absorbed by electrons in
 different chemical bond settings and leading to their dissociation. Exhibit B-9 shows the energy required
 to break different types of covalent bonds. The values presented in Exhibit B-9 are to be Viewed as trend-
 indicative and  not as exact values.  Exhibit B-9  shows  which wavelengths, and therefore ultraviolet
 energies, can interfere in the motions of a pair of electrons forming  a covalent bond to the level of
 breaking the  bond they form.  For example, the H-O bond in water will break under the effect of
ultraviolet light at a wavelength of about 185 nm.  This H-O bond break will lead  to the formation of
powerful hydroxyl  radicals.   In natural  waters,  these radicals react with organic compounds  or
microorganisms normally found in water and cause a change in their nature.
                           ,    '                           .                           .     •
Exhibit  B-10  presents important photochemical  reactions that relate to  organics destruction and
microorganisms disinfection. The photochemical reactions presented in Exhibit B-10 show the formation
of free radicals in water under the effect of ultraviolet light.
UV Light Disinfection Technology in
Drinking Water Application—An Overview    B-16                       Final—September 1996
-------
                              Appendix B.  Organics Destruction
          Exhibit B-8. Power of Light Erhitted by Mercury-Vapor Ultraviolet Lamps
Wavelength, nm
Infrared
1,367.3
1,128.7
1,0.14.0
Visible
578.0 (yellow)
546.1 (green)
435.8 (blue) .
404-5 (violet)
Ultraviolet
366.0
334.1
313.0
302.5
296.7
289.4 ,
280.4 -
275.3
270.0
265.2
257.1
253.7 (germicidal)
248.2,
240.0
232.0
184.9
• .
Total ultraviolet power
Power, W
Low-pressure
(85W)

' _
— ' •
- • -'
"•
3.04
0.26
.0.30
0.12

0.16
0.01
0.18
0.02
0.06
0.01 ,
0.01
0.01
—
0.02
• . ' — ' • -
30.00
. • — '
— -. '
— ,
1.80
32.30
Medium-Pressure
(550W)

4.6
3.8
12.2

23.0
28.2
23.3
12.7

30.1,
: 2.8
15.0
8.2
5.0
1.8
2.8
0.8
, 1-2
4.6
1.8
5.0
2.6
2.2
2.4
0.3
95.2
High-Pressure
(7J500W)

39.3
46.2
165.0
' •'
297.0
290.0
216.0
150.0

44.30
46.6 -
270.0
117.6
66.9
21.0
'63.9
'21.6,
22.9
158.0
31.0
137.0
41.8
31.9
31.2
8.2
1,619.1
 Source: Canrad-Hanovia, Inc., as cited in Legan, 1982.
UV Light Disinfection Technology in
Drinking Water Application—An Overview
B-17
                                                                  Final—September 1996
-------
                            Appendix B. Organics Destruction
                 Exhibit B-9. Dissociation Energies for Chemical .Bonds




Bond
Carbon
C-C
C-C
GeC
C-C1
C-F
C-H
C-N
C=N
CaN
C-O
C=O (aldehydes)
C=O (ketones)
C-S
• C=S
Hydrogen
H-H
Nitrogen
N-N
N=N
NsN
N-H (NH)
• N-H (NHg)
N-O
N=O
Oxygen
0-0(02)
-o-o-
O-H (water)
Sulfur
S-H
S-N
S-O


Dissociation
Energy,
kcal/gmol

82.6
145.8
199.6
81.0
116.0
98.7
72.8
147.0
212.6
85.5
176.0
179.0
- 65.0
166.0

104.2 .

52.0
60.0
226.0
85.0
102.0
48.0
162,0

119.1
47.0
117.5

83.0
115.0
119.0
UVLight
Maximum
Wavelength
to Break
Bond, nm

346.1
196.1
143.2
353.0
246.5
289.7 ;
392.7 ,
194.5
134.5
' 334.4
162.4
159.7
439.9
172.2 ,

274.4

549.8
476.5
126.6
336.4
280.3
595.6
' 176.5

240.1
608.3
243.3

344.5
248.6
240.3
Will UV Light at These
Wavelengths Break the Bond?



253.7 nm

yes
no
no
yes
•' no.
yes
yes
no
no
yes
no
no
yes
no

yes

yes
yes
no
yes
yes
yes
no

no
yes
no

yes
no
no


184.9 nm

yes
yes
no
yes
yes ,
yes
yes
yes
no
yes
no
no
yes
no

yes

yes
yes
no
yes
yes
yes
no

yes
yes
yes

yes
yes
yes
 Source:  Dean, 1973, as cited in Legan, 1982.
UV Light Disinfection Technology in
Drinking Water Application—An Overview
B-18
Final—September 1996
-------
                            Appendix B. Organics Destruction
          Exhibit B-10. Examples of Photochemical Reactions and Their Effects
Reaction
H20 + hv = H' + HO'
H202 + hv = 2 HO*
O2 + hv = O3
RH + hv = H' + FT
Fe+2 + hv = Fe*3 .
Fe(CN)6'4 4- hv = Fe(CN)6-3 "
NO + hv = N2 + O2
NO2 + hv = NO + O
NH3 + hv = NH2* + H* ,
Effective
Wavelength,
nm
184.9
253.7
253.7
184.9
253.7
184.9
184.9
313.0
184.9
Result
Water broken into free radicals
Hydrogen peroxide broken into hydroxyl radicals
Oxygen molecules converted to ozone
Organic broken into free radicals
Ferrous ion converted to ferric ion
Ferrocyanide ion converted to ferricyanide ion
Nitric oxide decomposed (smog avoided)
Nitric oxide formed (part of smog cycle)
Ammonia broken into free radicals '
  Source: Calvert and Pitts, 1966, as qited in Legan, 1982.

 B.5   ULTRAVIOLET LIGHT TECHNOLOGY AND CURRENT SAFE DRINKING
       WATER REGULATIONS
 Ultraviolet light is not identified as a Best Available Technology (BAT) for the treatment of any NPDWR
 contaminant, the  current advances in ultraviolet technology and its wide applications alone and in
 combination with ozone and hydrogen peroxide in treating ground water contamination in many Resource
 Conservation and Recovery Act (RCRA) Superfund sites strongly suggest its dual beneficial use. as a
 disinfectant and as an organics control technology.
UV Light Disinfection Technology in
Drinking Water Application—An Overview    B-19
Final—September 1996
-------
                              Appendix B.  Organics Destruction
 B.6    REFERENCES

 Berglind, L., Gjessing, E., and Johansen, E. Skipperud (1979). Oxidation Techniques in Drinking Water
 Treatment: Drinking Water Pilot Project, Report 11A, Advanced Treatment Technology. USEPA ODW,
 Washington,  DC. EPA-570/9-79-020.      ,

 Fessenden, R.J.,  and Fessenden,  J.S.   (1986).   "Spectroscopy I:   Infrared and Nuclear Magnetic
 Resonance."  Organic Chemistry:  pp. 313-317'.  Brooks/Cole Publishing Company.

 Francis, P.D. (1989). "Oxidation of Organic Pollutants by UV Light and Ozone: Modelling the Process
 Parameters in a Flow Reactor."  Ozone in Water Treatment,  pp. 672-687.

 Gaudy, A.F., and Gaudy, E.T.   (1980).  Microbiology for Environmental Scientists and Engineers.
 McGraw-Hill.                             ,                                        .

 Gehringer P. et al. (1993). "Groundwater Treatment for Chlorinated Ethylenes Using Ozone and Electron
 Beam Irradiation." Ozone in Water and Wastewater Treatment.  Vol 2, pp. S-13-26 - S-13-32.

 Giancoli, D.C. (1991). Physics,  Principles -with Applications. 3rd ed. Prentice-Hall.

 JHWC (1994). "Comparing Treatment Options for VOC-Contaminated Ground Water." The Hazardous
 Waste Consultant, pp. 1.20-1.24.

 Jody, BJ., Klein, M.J., and Judeikis, H. (1989).  "Catalytic O/UV Treatment of Wastewater Containing
 Mixtures of Organic and Inorganic Pollutants." Ozone in Water Treatment, pp. 619-631.

 Legan, R.W. (1982).  Ultraviolet Takes on CPI Role.  Chemical Engineering.  January 25, 1982.  pp. 95-
 100.             "   -                                                            -

 Leitzke, O. (1993). "Treatment of Contaminated Ground Water with the Ozone/UV Combination System."
 Ozone in Water and Wastewater Treatment. Vol 2, pp. S-13-15-S-13-25.

 McMurry, J. (1992).  Organic Chemistry. 3rd ed.  Brooks/Cole Publishing Company.

 Nick, K., et al. (1992).   "Degradation  of Triazine Herbicides by UV Radiation  Such as Used in the
 Disinfection of Drinking Water."   / Water SRT-Aqua  Vol 41, No 2, pp. 82-87.

 von Sonntag, G., and Schuchmann, H.P. (1992). "UV Disinfection of Drinking Water and By-Product
 Formation—Some Basic Considerations" J Water SRT—Aqua Vol. 41, No. 2, pp. 67-74.

Xu, S., et al. (1989).  "Treatment of Pyridine Containing Wastewater by Ozonation Under UV Irradiation."
 Ozone in Water Treatment,  pp. 743-750.                  ,                :

 Yu, Y., et al. (1989). "Comparison Between O3 and O/UV in Their Effects on the Biodegradability of
 Some Phenolic Compounds." Ozone in Water Treatment, pp. 751-765.

Zeff, J.D. (1993). "Testing of a Full Scale UV/Oxidation System to Obtain a Permit for Removing PCE
 from a Drinking Water at a Well Site in  the City of South Gate, California."  Ozone in  Water and
 Wastewater Treatment.  Vol 2, pp. S-13-1-S-13-14.

Zeff, JJD., Leitis, E. and Barich, J.T. (1989).  "UV-Oxidation Case Studies on the Removal of Toxic
 Organic Compounds in Ground, Waste and Leachate Waters." Ozone in Water Treatment, pp. 720-730.
UV Light Disinfection Technology in
Drinking Water Application—An Overview    B-20                      Final—September 1996
-------
 APPENDIX C.  QUESTIONNAIRE USED FOR STATE INQUIRY AND AS

                       GUIDE IN TELEPHONE INQUIRIES


        u.s. EPA                                             :    .   .
        SAIC Contract 68-C3-0365                                    -
        Ultraviolet Light Disinfection Study


 C.1    GENERAL SYSTEM QUESTIONS AND EQUIPMENT


        1.   What is the location of the system?                  '                           •


       .2.   What is the population served and design flow?                   ,   •'


        3.   When was the system installed?                           ." .   -


        4.   Why was UV treatment selected?  What was the anticipated advantage over traditional
            disinfection systems?


     ,   5.   Is the UV system a closed-type system or an open type system?


        6.   Is the system equipped with telemetry control system? Is there a fully automated backup
            system in place?


       7.  Was the UV system locally manufactured? Did it come with a warranty?


       8.  Does the public water, system have storage capacity? What is the capacity? "Open reservoirs
           or cisterns?


       9.  Type of treatment applied before and after UV. treatment (secondary disinfection)?


       10.  If chlorination is used as a secondary disinfectant what kind of chlorination (gas, chloramine,
           calcium or sodium hypochlorites)? What are the assumed and residual doses?


       11.  How are UV intensity and dose measured?                                  .


C.2   WATER DATA
                                  • *      '               .                     •

       1:   What is the maximum turbidity levels before and after UV treatment?


       2.   What are the maximum iron levels in source water or before UV treatment?


       3.   Have there been any coliform outbreaks? Any increase in biofilm formation in the network
           has been noticed?


       4.   Have there been any microbiological problems?
UV Light Disinfection Technology in
Drinking Water Application—An Overview    C-l                     Final—September 1996
-------
      Appendix C.  Questionaire Used for State Inquiry and as Guide in Telephone inquiries

 C.3    OPERATION AND MAINTENANCE

        1.   How often does the system get cleaned?

        2.   Is the system equipped with  mechanical wipers? Ultrasonic cleaners? Are cleaning agents
            used to clean the system manually? Is water Tinder high pressure used to clean the units? At
            what  pressure? If any which cleaning agents are used (synthetic detergents,  dilute
            hydrochloric acid, dilute sulfuric acid, dilute phosphoric acid)?

        3.   Was any special training provided for employees dealing with UV equipment?

        4.   How much time does it take to clean a unit? How many persons do the cleaning at a time?

        5.   How often does a sleeve or bulb get broken during cleaning?

        6.   How often are bulbs, sleeves, diodes, and ballasts replaced?             .

        7.   How often and by what method does the system get calibrated?

 C.4    COSTS                                                            ,

        1.   What was the cost of the system?

        2.   Were engineering, installation, and  training included in the price?  If not, what was the ,
            additional cost?

        3.   What are the operation and maintenance costs? What are the labor requirements (hours per
            week) and costs?                .                          .

       4.   If the system is equipped with telemetry control, what was the cost?

 C.5    ON-SITE CONTACT

        1.   Contact name, phone number, and address
UV Light Disinfection Technology in
Drinking Water Application—An Overview
C-2
Final—September 1996
-------
    APPENDIX D.  REGULATIONS AND STANDARDS  FOR DRINKING
            WATER DISINFECTION USING ULTRAVIOLET LIGHT

  D.   INTRODUCTION
  This appendix provides available regulations and standards regarding the use of ultraviolet light for
  drinking water disinfection.  This appendix includes the 1966 U.S. Department of Health, Education, and
  Welfare (DREW) policy statement on the use of ultraviolet light for water disinfection (copies provided
  by Ideal Horizons, Inland Atlantic Ultraviolet Corporation).  Also, this appendix presents ultraviolet light
  regulations, guidance, and standards used in .the States of Utah, Wisconsin, Pennsylvania, and New Jersey.
  In addition, Sections 1 through 6 and the preface of the ANStfNSF Standard 55-1991 are presented in this
  appendix. These excerpts are reprinted with permission from NSF International.  All the regulations,
 guidance, and standards are copied verbatim and seriatim from documents provided by the respective
 State's drinking water supervision managers.                                     -
UV Light Disinfection Technology in
Drinking Water Application—An Overview
D-l
                                                                Final—September 1996
-------
  Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light
 D.1   DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
                                                                               [April 1, 1966]
                DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
                                PUBLIC HEALTH SERVICE
                    Division of Environmental Engineering and Food Protection
            Policy Statement on Use of the Ultraviolet Process for Disinfection of Water

 The use of the ultraviolet process as a means of disinfecting water to meet the bacteriological requirements
 of the Public Health Service Drinking Water Standards is acceptable provided the equipment used meets
 the criteria described herein.

 In the design of a water treatment system, care must be exercised to insure that all other requirements of
 the Drinking Water Standards relating tp the Source and Protection, Chemical and Physical Characteristics,
 and Radioactivity are met.  (In the case of an individual water supply, the system should meet the criteria
 contained in the "Manual of Individual Water Supply Systems", Public Health Service Publication # 24.)
 The ultraviolet process for disinfecting water will not change the chemical and physical characteristics of
 the water. Additional treatment, if otherwise dictated, will still be. required, including possible need for
 residual disinfectant^ in the distribution system.

 Color, turbidity, and organic impurities interfere with the transmission of ultraviolet energy and may
 decrease the disinfection efficiency below levels requked to insure destruction of pathogenic organisms.
 It may be necessary to pretreat some supplies to remove excess turbidity and color. In general, units of
 color  and turbidity are not adequate measures  of the decrease that may occur in  ultraviolet energy
 transmission. The organic nature of materials present in waters can give rise to significant transmission
 difficulties. As a result, an ultraviolet intensity meter is required to measure the energy levels to which
 the water is subjected.               •

Ultraviolet treatment does  not provide residual bactericidal action. Therefore, the  need for periodic
flushing and disinfection of the'water distribution system must be recognized.  Some supplies may require
routine chemical disinfection, including the maintenance of a residual bactericidal agent throughout the
distribution system.
UV Light Disinfection Technology in
Drinking Water Application—An Overview    D-2                      Final—September 1996
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   Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

  D.1   DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE (CONTINUED)

                   Criteria for the Acceptability of an Ultraviolet Disinfecting Unit


  1.     Ultraviolet radiation at a.level of 2,537 Angstrom units must be applied at a minimum dosage of
        16,000 microwatt-seconds per  square  centimeter at all points.throughout the water disinfection
        chamber.

  2.    Maximum water depth in the chamber, measured from the tube surface to the chamber wall, shall
       not exceed three inches.                                                           -   '

  3.    The ultraviolet tubes shall be:

       A.   Jacketed so that a proper operating tube temperature of about 105°F is maintained.
       B.   The jacket shall be of quartz or high silica glass with similar optical characteristics.

 4.    A flow or time delay mechanism shall be provided to permit a two minute tube warm-up period
       before water flows from the unit.

 5.    The unit shall be designed to permit frequent mechanical cleaning of the water contact surface of
       the jacket without disassembly of the unit.

 6.    An automatic flow control valve, accurate within the expected pressure range, shall be installed to
       restrict flow to the maximum design flow of the treatment unit.

 7.    An^ accurately calibrated ultraviolet intensity meter, properly filtered to restrict its sensitivity to the
       disinfection spectrum shall be installed in the wall of the .disinfection chamber at the point of
       greatest water depth from the tube or tubes.          •

 8.     A flow diversion valve or automatic shut-off valve shall be installed which will permit flow into
       the potable water system only when at least the minimum ultraviolet dosage is applied. When
       power is not being supplied to the unit, the valve should be in a closed (fail-safe) position which
       prevents the flow of water into the potable water system.

 9.     An automatic, audible alarm shall be installed to warn of malfunction or impending shutdown if
       considered necessary by the Control or Regulatory Agency.

 10.   The materials of construction shall not impart toxic materials into the water either as a result of the
      presence of toxic constituents in materials of construction or as a result of physical of [sic] chemical
      changes resulting from exposure to ultraviolet energy.

 11.   The unit shall be designed to protect the operator against electrical shock or excessive radiation.
UV Light Disinfection Technology in
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  Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.1  DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE (CONTINUED)

 As with any potable water treatment process, due consideration must be given to the reliability, economics,

 and competent operation of the disinfection process and related equipment, including:


 1.    Installation of the unit in a protected enclosure not subject to extremes of temperature which cause
      malfunctions.                              •   •

 2.    Provision of a spare ultraviolet tube and other necessary  equipment to  effect prompt repair by
      qualified personnel properly instructed in the operation and maintenance of the equipment.

 3.    Frequent inspection of the unit and keeping a record of  all operations, including maintenance
      problems.                                         .          '  .
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   Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

  D.2  UTAH


                                 R309 Drinking Water Regulations
                            Utah Department of Environmental  Quality,
                                    Division of Drinking Water

  R309-107-9. Ultraviolet Light.



  Proposals for use of ultraviolet disinfection should be discussed with the Division of Drinking Water prior

  to the preparationi of final plans and .specifications.



 Secondary disinfection and maintenance of the required residual will.be necessary where disinfection of

 the supply is required.



 Ultraviolet disinfection will be permitted where the design conforms to the minimum recommendations

 of the U.$. Public Health Service listed below.        .



 (1)  Ultraviolet radiation at a level of 2,537 Angstrom units mus~t be applied at a^minimum dosage of
      16,000 microwatt-seconds  per square centimeter per second (1,600 Finsen Units), at all points
      throughout the water disinfection chamber.                                          .

 (2)  Maximum water depth in the chamber, measured .from the tub surface to the chamber wall, shall
      not exceed three inches.                         •

 (3)   The ultraviolet tubes shall be:

 (a)   Jacketed so that a proper operating tube temperature of about 105 degrees F is maintained.

 (b)   The jacket shall be of quartz, or high silica glass wim similar  optical characteristics.

 (4)   A flow or time delay mechanism shall be provided to permit  a two minute tube warm-up period
      before water flows from the unit.
                                                                                   s
 (5)   The unit shall be designed to permit frequent mechanical cleaning of the water contact surface of
      the jacket without disassembly of the unit.

 (6)   An automatic flow control valve, accurate within the expected  pressure range, shall be installed to
      restrict flow to the maximum design flow of the treatment unit.                             •  f

 (7)   An accurately calibrated ultraviolet intensity meter, properly filtered to restrict its sensitivity to the
      disinfection spectrum, shall be installed in the wall  of the disinfection chamber at the point of
      greatest water depth from the tube or tubes.           .
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  Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.2  UTAH (CONTINUED)

 (8)   A flow diversion valve or automatic shut-off valve shall be installed which will permit flow into
       the potable water system only when at least the minimum ultraviolet dosage is applied.  When
       power is not being supplied to the unit, the valve should be in a closed position which prevents the
       flow of water into the potable water system.

 (9)   An automatic, audible alarm shall be installed to warn of malfunction or impending shutdown.

 (10)   The materials of construction shall not impart toxic materials into the water either as a result of the
       presence of toxic constituents in materials of construction or as a result of physical or chemical
       changes resulting from exposure to ultraviolet energy.

 (11)   The unit shall be designed to protect the operator against electrical shock or excessive radiation.

 (12)   As with any potable water treatment process, due consideration must be given to the reliability,
       economics, and component operation of the disinfection process and related equipment, including:

 (a)    Installation of the unit in a protected enclosure not subject to extremes of temperature which could
       cause malfunction.

 (b)    Provision of a spare UV tube and other necessary equipment to effect prompt repair by qualified
       personnel properly instructed in the operation and maintenance of the equipment.
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                P- Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light
     D.3  WISCONSIN

            ,                   Department of Natural Resources Criteria for
                                 Ultraviolet (UV) Water Treatment Devices
.                           for Private and Non-Community Public Water Supplies
                                 To Control Microbiological Contamination
                                           November 17,  1995      ,                     .
     .Introduction

     The Department'has historically required use of wells that naturally produce bacteriologically safe water.
     The rational is that  micrqbiologically safe groundwater provides the best long-term public health
     protection.  The potential for providing a naturally safe water source must be fully evaluated and found
     to be impracticable before a treatment process caii be approved by the Department.
  .,           •-              -'"'"'.      ' •                    ''           /
     This document^contains information about UV treatment design criteria for microbiologically contaminated
     private and non-community public water supplies. It contains general information and guidance, specifies
     when DNR approval is required, lists information that is to be submitted for DNR approval and lists likely
     approval conditions.  Refer, to the well code, Chapter NR 812, Wis.  Adm., Code, specifically  ss. NR
     812.09 and NR 812.37, for specific administrative code requirements.                             :

    General

    Well owners may  install a UV water treatment system  on  a safe water supply without Department
    approval.  The Department recommends that the owner comply with the design criteria specified in the
    remainder of this document.  Unsafe water supply  wells eligible for UV treatment are those that have
    confirmed positive test results for total coliform or Escherichia coli bacteria more than once, have failed
    three attempts at batch chlorination to eliminate the problem and which do not appear to be correctable
    by well reconstruction  or replacement.

    Wells where treatment is proposed for microbiological contamination shall comply with chapter NR 812,
    Wis. Adm. "Code requirements.  The well depth and depth of casing must be determined from the well
    construction  report  or  an actual  measurement.  Casing depths shall  meet either the special  casing
    requirement-for the  area or be extended to a greater depth than the present special casing requirement.
    An exception may be made when the Department agrees that there is a low probability of acquiring safe
    water at a greater depth. In this case, the required minimum well casing depth shall be determined on a
  / case-by-case basis.
   UV Light Disinfection Technology in       ~-  ~~                  """                  •
   Drinking Water Application—An Overview     D-7          /            Final-September 1996
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  Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.3  WISCONSIN (CONTINUED)

 Private residential UV water treatment devices serving one or two dwellings must be approved by the
 Department of Industry, Labor and Human Relations (DILHR) prior to installation or sale.  Installation.
-must be made according to manufacturers printed instructions  and Chapters BLHR  81  through  86,
 Wisconsin Administrative Code. An owner may install the treatment device on their residence.  A
 licensed pump installer or plumber is required for installation on rented property that an owner does not
 occupy and for non-community systems. Contracted work shall be done by a licensed pump installer if
 the device will be installed before the pressure tank.  A licensed plumber must install the equipment after
 the pressure tank. All work must comply with applicable code requirements.


 Water .Quality Characteristics

 The water supply shall be analyzed for the following water quality parameters and the results shall be
 included in the UV application. Pretreatment is required for UV installations if the water quality exceeds
 any of the following maximum limits. When an initial sample exceeds a maximum limit, a check sample
 shall be taken and analyzed.
           Parameter
           Color       •   ,
           Dissolved Iron
           Dissolved Manganese
           Hardness
           Hydrogen Sulfide
           Iron Bacteria
           PH
           Suspended Solids
           Turbidity
           Total Coliform
           Escherichia coli
Maximum
15 APHA units
0.3 mg/L
0.05 mg/L
120 mg/L
Non-Detectable
None
6.5 to 9.5
10 mg/L
5.0 NTU,
1,000  Colonies/100 mg/L
100           .
Preferred
No APHA units
<0.01 mg/L
<0.0004mg/L
17.1  mg/L
Same
Same
Same
<1 mg/L
1.0 NTU
Raw water quality shall be evaluated and pretreatment equipment shall be designed to handle water quality

changes.  Turbidity caused by rainfall events is of special concern.


UV with Microfiltration Approval Process

DNR approval is required prior to installation of a UV water treatment device on a microbiologically
unsafe water supply.
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   Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light
  D.3  WISCONSIN (CONTINUED)
  1.   'The owner must sign a short statement describing the steps taken to correct the microbiological
  problem and send it along with the application to:
                                  DNR Private Water Supply WS/2
                                            Box 7921                                          ,
                                     Madison, WI 53707-7921
  2.    The DNR win review the application for completeness.  Incomplete materials will be returned
  Disapproved applications will be returned to the applicant with the reasons for disapproval  There is no
  fee for reviewing the application.
  3.    Installation of the  DNR approved  water treatment system  may proceed  subject to approval
  conditions.  Most approvals require:                                                    ,
       a.     Installation according to the submitted plans and approval conditions.
 '   •.   b.     Initial sampling of raw water and treated water at startup and a routine sampling program.
       c.     Routine maintenance requirements.
       .d.     Non-Community public water supply systems will be required to submit periodic reports of
             sample results and maintenance actions to the Department.

 Application
 The information that is required for a complete application is  found in the attached outline.   The
 Department asks that you take the time to obtain the information specified and be as complete as possible
 in your application.  Information as requested in item #5 on the attached outline about .the depth of well
 casing, casing integrity and the well's .total depth must be obtained in order to evaluate the request. In
 addition, the water quality data specified in item #6 on the attached outline is critical in designing a UV
 water treatment system. Attached are the UV specifications that must be met in order for the Department
 to approve the installation of the water treatment device(s) on a microbiologically unsafe water supply.
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  Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.3  WISCONSIN (CONTINUED)

 Application Content
  1.    Property Owner:   .

  2.    Water Treatment Device,
        Operator:
  3,    Property Location and Legal
       Description:
  4.    Property Map:
  5.    Well Description:
 6.    Water Quality:
 7.    Water Quantity:
  Include the name, mailing address, and telephone number.

  Provide the name, mailing address and telephone number
  of the water treatment device operator if different from
  owner above.

  Provide the village or city street and number or if rural,
  the road and fire number and the legal description
  including the 1A1A Section, V* Section, Section number,
  Town and Range numbers, and County.

  Locate the property on a map.  A plat map or topographic
  map is acceptable.

  Provide a copy of the well construction report if available.
  If not available, provide the  following information:
  a.    The approximate date  of well construction,
  b.    The total depth of the  well and
  c.    The depth of the casing in the well.
  d.    A copy of an inspection report showing compliance
      .of the well and pumping system with Chapter
       NR812.                          !

 Results of the following well water quality tests collected
 at the well sampling faucet:

 a.    Total coliform bacteria,
 b.    E-Coli bacteria,
 c.    Iron bacteria,                     •
 d.    Color,
 e.    Dissolved iron,
 f.-    Dissolved'manganese,                 •  .
' g.    Hardness,
 h.    Hydrogen sulfide if odor is present,
 i.     pH,
 j.     Suspended solids,
 k.    Turbidity

 These tests shall be performed by a state Safe Drinking
 Water Act certified laboratory.

 Measure or estimate the average daily water usage in
 gallons.  Indicate the pump capacity in gallons per
 minute.
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  Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.3  WISCONSIN (CONTINUED)
  8.
Water Distribution System
Sketch:
  9.
Water Treatment Device or
System Installation Information:
  10.   Maintenance Program:
Provide a sketch of the water distribution system from the
well to the final treated water distribution point including
the location of any sampling faucets, pressure gauges,
shutoff valves, by-pass piping, pressure tanks, any other
treatment devices, and the proposed location of the water
treatment device or water treatment system.

Provide the name of the manufacturer, the product name
and model number.

Describe the required maintenance for the UV water
treatment device and any pretreatment devices to be
installed. Provide a copy of any maintenance and
operational agreements. Specify the responsible party for
maintaining the water treatment system.
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                                    D-ll
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  Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.3  WISCONSIN (CONTINUED)

 DESIGN AND OPERATIONAL CRITERIA

 FOR POINT-OF-ENTRY INSTALLATIONS USING ULTRAVIOLET (UV) FOR PRIVATE AND
 NON-COMMUNITY WATER SUPPLY SYSTEMS.

 The following are Wisconsin Department of Natural  Resources (WDNR) criteria for installation,

 monitoring and replacement requirements for consideration of UV treatment of a microbiologically unsafe

 water for private and non-community public water supplies. The following criteria must be met in order

 to install a UV water treatment device on a bacteriologically unsafe water supply well.


 A.   CRITERIA FOR UV WATER TREATMENT DEVICES

      1.    UV water treatment devices must comply with Class A criteria under the American National
      Standard Institute  (ANSI)/National Sanitation Foundation  (NSF) Standard 55  -  Ultraviolet
      Microbiological Water Treatment Systems;  Residential UV models shall be approved by the
      Department of Industry, Labor and Human Relations (DILHR); each UV water treatment device
      shall meet the following standards;

            a.    Ultraviolet radiation at an [sic] wavelength  of 253.7 nanometers shall be applied at a
      minimum dose of 38,000 microwatt-seconds per square centimeter (uW-sec/cm2) at the failsafe set
      point at the end of lamp life;

            b.    The UV device shall be fitted with a lamp viewing port to safely visually verify
      electrical operation of the lamp(s);

            c.    The UV light assembly shall be insulated form direct contact with the influent water
      by a lamp jacket and the lamp and lamp jacket shall be  replaceable;              '

            d.    An automatic  fixed flow rate control  shall be provided to prevent flow above the
      manufacturer's  maximum rated  flow over the manufacturer's recommended  operating  pressure
      range;                           •         .     •,

            e.    The UV assemblies shall be accessible for visual observation, cleaning and replacement
      of the lamp jackets and sensor window/lens;

            f.    The ultraviolet tube(s) shall be 1) jacketed so that a proper operating lamp temperature
      of about 104 degrees Fahrenheit is maintained and  2) the jacket shall be of quartz or high silica
      glass with similar optical and strength characteristics;

            g.    A  narrow band  UV monitoring device shall be provided.  It shall be  accurately
      calibrated to 253.7 nanometers and installed at the point of greatest water depth. The device  shall
      trigger an audible alarm in  the event the sensor or lamp fails or if insufficient dosage is  detected
      as defined in item "a" above;
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  Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.3   WISCONSIN (CONTINUED)

            h.    An automatic shutdown valve shall be installed ahead of the UV treatment system that
       will be activated whenever the water treatment-system loses power or is tripped by a monitoring
       device when me dosage drops below 38,000 uW-sec/cm2.

            i.     The UV housing shall be stainless steel 304 or 316L;

       2.    A flow delay mechanism shall be provided to permit a sufficient time for tube warm-up per
       manufacturer recommendations before water flows  from the unit upon startup.

       3.    Identical parallel UV treatment systems shall be provided at public water systems to provide
       a continuous water supply when one unit is out of service;

       4.    No bypasses shall be installed;

       5.    All water from the well shall be treated;                      •

       6.    The well pump shall have adequate pressure  capability to maintain minimum water system
       pressure after the water treatment devices;             ;


B.    PRETREATMENT                                                            '

       1. ••   A 5 micron sediment prefilter shall be installed before the UV device. The filter model shall
      be approved by DILHR" if installed on a residential  water supply;       ,

      2.    A filter rated for cyst reduction shall be installed before the UV device.  The filter shall be'
      approved by DILHR if installed on a residential 'water supply;

      3.    The prefilter and cyst reduction filter shall be replaced when the pressure loss across an in
      use filter has increased by 10 psig above a clean new filter at the manufacturers rated service flow
      rate.              •  •.                                  .

      4.     Other pretreatment water treatment devices may be necessary depending on source water
      quality.


C.    REQUIRED ONGOING WATER QUALITY MONITORING

      Total coliform monitoring will be used to evaluate  UV treatment effectiveness.  The monitoring
      frequency will be as follows:

      Startup and 2 weeks after start up - one raw and one treated sample - all systems
      Monthly thereafter for all public water systems - raw and treated
      Private water system owners  are encouraged, but not required, to routinely monitor effectiveness
      of the water treatment system.

     ' Monitoring  for additional parameters or total coliform on an increased frequency may be required
      by the Department on a case-by-case basis.


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  Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.3  WISCONSIN (CONTINUED)

 D.    OVERSIGHT AND MONITORING

       UV light intensity of each installed unit shall be monitored continuously., Treatment units and the
       water system shall automatically shutdown if the UV dosage falls below the required output of
       38,000 uW-sec/cm*. Water systems that have a large variation in the turbidity of the water source
       may be required to install a turbidimeter ahead of the UV water treatment device.  An automatic
       shutdown valve shall be installed and operated in conjunction with the turbidimeter. Each owner
       shall  have at least one replacement lamp, quartz sleeve, 5 micron replacement, filter and cyst
       reduction filter available onsite.

 E.    SEASONAL OPERATIONS

       UV water treatment devices that are operated on a seasonal basis shall be inspected and cleaned
       prior  to use at the start of each operating season. All prefilters shall be replaced prior to start up
       of the water supply system after a shut down of greater than three months. The UV water treatment
       system including the filters shall be disinfected prior to placing the water treatment system back into
       operation.  A  procedure for  shutting down and starting up the UV treatment system shall be
       developed for or by each  owner based upon manufacturer  recommendations and submitted  in
       writing to the department.                                      *

 F.    APPLICATION, RECORD  KEEPING and ACCESS

      A record shall be kept of the water quality test data,  dates of lamp replacement and  cleaning, a
      record of when the device was shutdown and the reason for shutdown, and the dates  of prefilter
      replacement.

      Department representatives shall have access to the UV water treatment system and records.

      Non-community wajer systems will be required to submit operating reports and required sample
      results on a monthly or quarterly basis as described in the conditions of approval.
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  Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

  D.4  PENNSYLVANIA
                                                      ?                                '

                              Public Water Supply Manual - Part IV
                             Noncommunity System Design Standards
                      Pennsylvania Department of Environmental Protection

 3.3   Ultraviolet Irradiation (UV)

       Ultraviolet light produced by UV lamps has been shown to be effective bactericide for certain
       pathogenic bacteria. However, the department does not consider the use of UV acceptable for the
       inactivation of Giardia lamblia. Only UV systems approved as Class A units under the National
       Sanitation Foundation (NSF) Standard 55 - Ultraviolet Water Treatment Systems are acceptable for
       use in drinking water disinfection.

       Ultraviolet light disinfection will be considered only for small nonresidential water supplies and in
       certain special cases where other methods are not considered feasible. As ultraviolet treatment does
       not provide a residual disinfectant, post-chlorination may be required to maintain safe water in the
       system.   ,                                                               ~    •

       UV system or component shall be designed and constructed so that its intended purpose shall be
       accomplished  when  installed and operated according  to  the manufacturer's  instructions.
       Components shall not be adversely affected by the normal environment to which they are subjected.
       Normal environment shall include usual vibration, shock, climate condition and cleaning procedures
       as prescribed by the manufacturer.

       3.3.1 Materials
  -   -     .      •••• V    '•     -      •--  ''•         ~,    '-•'; •     '
          , The materials in contact with water must not impart undesirable taste, odor, color, and/or
            toxic materials into the water as a result of the presence of toxic constituents in materials of
            construction or as a  result of physical or chemical  changes resulting from exposure from
            ultraviolet energy. Materials exposed to ultraviolet irradiation shall be formulated to  resist
            deterioration and shall not impart undesirable tastes, odor, color, and/or toxic chemicals to
            the water upon irradiation.

            Systems and/or  components  shall  be constructed of materials  suitable  to  withstand
            temperatures generated during sustained periods when the unit is not in use.

      3.3.2 Design Criteria

            The use of UV devices as a means of disinfection of public water supplies in Pennsylvania
            is acceptable provided the equipment used meets the design criteria described herein:

            1.     Ultraviolet radiation at a level of 2,537 Angstrom units must be applied at a minimum
                  dosage of 16,000 microwatt-seconds per square centimeter at all points throughout the
                 , water disinfection  chamber;                  .

            2.     The UV system or component  shall be provided with a visual  means  to verify
                 .electrical operation of lamps;
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 Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.4  PENNSYLVANIA (CONTINUEQ)

            3.    UV lamp assemblies shall be designed to be insulated from direct contact with the
                  influent water. If the ultraviolet lamps or assemblies are intended to be replaced, they
                  shall be removable;

            4.    The unit is to have an automatic flow control device, accurate within the expected
                  range of operating pressures, so that the maximum design flow rate of the unit is not
                  exceeded;

            5.    The systems and all components subject to  line pressure shall be designed for a
                  working pressure of at least 689 kPa'(100 psig);

            6.    The system or component' shall be  designed  to  be accessible for cleaning and
                  replacement of the lamp jackets and sensor window/lens which are provided on the
                  systems. The manufacturer's cleaning procedures shall result in thorough cleaning of
                  the system. The treatment chamber shall be designed so that at least one end can be
                  dismounted for cleaning.

            7.    Maximum water depth in the chamber measured from the tube surface to chamber wall
                  must not exceed three inches;                            .                     .

            8.    The ultraviolet tubes must be:               •            '

                  a.    Jacketed so that a proper operating tube temperature of  about  105° F is.
                       maintained,

                  b.    The jacket  shall be  of quartz or high  silica glass  with  similar  optical
                       characteristics;                                                          :

            9.     A flow or time delay mechanism is to be provided to permit a two minute tube warm-
                  up period before water flows from the unit;

            10.    An accurately calibrated  ultraviolet intensity  meter, properly filtered to  restrict its
                  sensitivity to the disinfection chamber at the point of greatest water depth from the
                  tube(s) shall be provided;

            11.    A flow diversion valve or automatic shut-off valve is to  be installed which permits
                  flow into the potable water system only when at least the minimum ultraviolet dosage
                  is applied.  When power is not being  supplied to the unit, the valve should  be in a
                  closed (fail-safe) position which prevents the flow of water into the potable water
                  system;                        '

            12.    The unit must incorporate a device for monitoring or sending ultraviolet transmission
                  or intensity through the maximum depth of water in the chamber during operation.
                  The monitoring or sensing device is to be installed that triggers an audible alarm hi
                  the event of lamp or sensor failure or if insufficient ultraviolet light reaches the sensor;

            13.    The unit must protect the operator against electrical  shock or excessive  ultraviolet
                  energy;


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  Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.4  PENNSYLVANIA (CONTINUED)

            14.   The operation of the ultraviolet light unit shall be synchronized with the operation of
                  the well pump.                        ,

       3.3.3 Installation                                                                      ,


            1.     The unit should be installed  in a protected enclosure not subject to extremes of
                  temperature which could cause malfunction.    .

            2.     Spare UV tubes and other necessary equipment are to be provided to effect prompt
                  repair by qualified personnel properly instructed in the operation and maintenance of
            .the equipment.                                ,


           "3.     The unit is to be installed so as to allow ease of access for disassembly, repairs, or
                  replacement.                                '     '    •
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  Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

  D.5  NEW JERSEY
               NEW JERSEY PROPOSED REGULATIONS FOR DISINFECTION
        BY ULTRA-VIOLET LIGHT AS APPEARED IN THE NEW JERSEY REGISTER
                            CITE 27 NJ.R.4112 NOVEMBER 6,1995

 (c) Regulations for disinfection by ultra-violet light are as follows:

 1.    Ultra-violet tubes shall be jacketed so that a temperature of 105 degrees Fahrenheit is maintained.
 2.
 4.
 5.
 6.
 7.
 The jacket on the ultra-violet light tubes shall be quartz or high-silica glass with similar optical
 characteristics.
 3.    The ultra-violet light disinfection unit shall be designed to permit frequent mechanical cleaning of
       the water contacts surface of the ultra-violet tube jacket without disassembly of the unit.
The maximum water depth in the disinfection chamber, measured from the ultra-violet light tube
surface to the outer walls of the chamber, shall not exceed three inches.

Ultra-violet radiation at a level of 2,537 Angstrom shall be applied at all points throughout the
disinfection chamber at a minimum rate of 16,000 microwatt seconds per square centimeter.

An automatic flow control valve, accurate within the expected pressure range, shall be installed to
restrict flow to the maximum design flow of the  ultra-violet disinfection unit.

An accurately calibrated ultra-violet  light intensity meter, filtered to confine its sensitivity to the
range of disinfection spectrum, shall be installed in the wall of the disinfection chamber at the point
of greatest water depth from the light transmitting source.
 8.    A flow diversion valve or automatic shut-off valve controlled by the ultra-violet light intensity
      meter shall be installed so as to permit water flow into the water system only when the minimum
      radiation level specified at (c)5 is applied.  When power is not being supplied to the unit, the valve
      shall be in a closed (fail-safe) position to prevent the flow of water into the water system.

 9.    The ultra-violet light disinfection unit shall be installed in a manner such that it cannot be bypassed.
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                                      D-18
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   Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light
  D.6  ANSI/NSF STANDARD 55-1991
                                          STANDARD55
                                               FOR
            ULTRAVIOLET MICROBIOLOGICAL WATER TREATMENT SYSTEMS
                                            PREFACE
,  This standard was developed  for the purposes of establishing reliable methods  for determining the
  performance,of point-of-entry and point-of-use ultraviolet water treatment systems designed to reduce
  specific contaminants from public or private water supplies,  Systems covered by this standard are in
  keeping with the Report of Task Force on Guide Standard and Protocol for Testing Microbiological Water
  Purifiers, April 1987.l                                             .

  It is recognized that the federal, state and local objective is to provide a safe water supply without user
  treatment.  However, many users are faced with the presence of contaminants of both aesthetic and health
  concern in their water supply and need guidance as to the availability of tested and certified point-of-entry
  and point-of-use ultraviolet water treatment systems.  This standard will help to'meet this need, but cannot
  be expected to address claims beybnd those covered in this standard.

  Since it was  not  economically feasible to mount a  routine  testing program using  all of the target
  microorganisms, e.g.,  bacteria, viruses, and protozoan cysts, an equivalent "disinfection" set of tests and
  requirements were developed for point-of-use and point-of-entry ultraviolet disinfection systems.

  A virus reduction of 4-log against a poliovirus and rotavirus challenge and a bacteriological reduction of
  6-logs against a challenge of a coliform bacteria (Klebsiella terrigena) has been recommended by Schaub
  and an expert task force (1987).2                                                    ;        ••'  '

  The technical and health protection problems (laboratory staff)  and the inherent cost of establishing and
  maintaining a live virus test program precludes its routine application in a multipurpose standards testing
  laboratory.   Consequently, an alternate means of assuring virus efficacy  was developed.
     Guide Standard and Protocol for Testing Microbiological Water Purifiers, Report of Task Force, submitted bv Steven
 A. Schaub to the USEPA, April 1987.                                   -
'                '•        '                   ••.'-.•          •.•••-,-•.'•'
 ~  2Ibid.,p. 7.                          -             '      •             .

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   Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light
  D.6  ANSI/NSF STANDARD 55-1991 (CONTINUED)
  Survival data for poliovirus and rotavirus (Chang, 1985)3, show between a 3 to 4-log reduction in both
  poliovirus and rotavirus may be accomplished by a UV'dosage of 30,000 fiW-sec/cm2 while a greater than
  6-log reduction of Escherichia coli may be projected.  Additional data (Harris,  1986)4 shows a 5 log
  reduction of poliovirus at 40',000 uW-sec/cm2.  Consequently, a minimum UV dosage of 38,000 uW-
  sec/cm2 at the failsafe setpoint is set as an equivalent 4-log virus reduction requirement.

  Since ultraviolet light has limited cysticidal ability, information will be required for the use as to the need
  for a prefflter complying with ANSI/NSF Standard 53: Drinking Water Treatment .Units - Health Effects
  for cyst reduction.

  Where drinking water is considered to be free of disease causing pathogenic organisms and has a turbidity
  level within acceptable drinking water standards, ultraviolet treatment may be useful for the supplemental
  treatment  of this  drinking water.  It would  be suitable for the reduction  of normally  occurring
  microbiological flora (non-spore forming heterotrophic  bacteria)  commonly found in drinking water.
  Survival data (Chang, 1985)5  show a greater than 2 log reduction of non-spore forming heterotrophic
 bacteria may be accomplished by an ultraviolet dosage of 16,000 uW-sec/cm2.   The yeast  organism
 Saccharomyces cerevisiae was chosen as the test challenge to allow for a reasonable influent concentration
 and an easily measured reduction in the effluent. Most vegetative bacteria including cbliform species are
 too susceptible to UV radiation at the dose range of 16,000 uW-sec/cm2 to allow for measurable testing.

 This standard and the accompanying testing program will provide assurance to the use and the regulatory
 officials that point-of-entry and point-of-use ultraviolet water treatment systems will perform, with proper
, operation and maintenance, in accordance with the claims made under the standard.  However,  final
 acceptance of systems for any application covered under governmental regulation will be subject to the
 approval of the appropriate federal, state, and/or local regulatory agency having jurisdiction.
    *UV Inacdvation of Pathogenic and Indicator Microorganisms, Chang, J.C., Johnson, J. Donald, et al. Journal of
 Applied Environmental Microbiology, Vol. 49, pp. 1361-1365, 1985.
    *UV Inactivation of Selected Bacteria and Viruses With Photoreactivation of the Bacteria, Harris, D.'George Adams
 Dean, et al., Water Resources, Vol, Vol. 21, pp. 687-692, 1986.                                            .
    slbid., p. 1362.

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   Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

  D.6  ANSI/NSF STANDARD 55-1991 (CONTINUED)

                                   SECTION 1.  GENERAL


  1-0   SCOPE:   This standard covers  ultraviolet (0V) microbiological  water treatment  systems and
        components for point-of-use (POU) and point-of-entry (POE) applications.  Systems are intended
        to be used under the following specific conditions.

        1.0.1  CLASS  A SYSTEMS:  Class A point-of-entry and point-of^use systems covered by this
             standard are designed to disinfect and/or remove microorganisms from contaminated water
             including bacteria and viruses, to a safe level.   Systems covered by this standard are not
             intended for the treatment of water that has an  obvious contamination source, such as raw
             sewage; nor are systems intended to convert wastewater to microbiologically safe drinking
        .    water. The systems are intended to be installed on visually clear water (not colored, cloudy,
            or  turbid).  Systems intended for treatment of surface waters will need to  be installed
            downstream of a prefilter tested for cyst reduction in compliance with ANSI/NSF Standard
            53:  Drinking Water Treatment Units - Health Effects.

       1.0.2 CLASS B SYSTEMS OR COMPONENTS: Class B poiht-of-use systems covered by this
            standard are designed for supplemental bactericidal treatment of treatedand disinfected public
            drinking  water or other drinking water which has been tested and deemed acceptable for
            human consumption by the state or local health  agency having jurisdiction. The system is
            designed to reduce normally occurring nonpathogenic or nuisance microorganisms only. The
            Class B system is not intended for the disinfection of microbiologically unsafe water.

 1.1    MINIMUM REQUIREMENTS:  Variations from these minimum requirements may be permitted
       if they make the system or component as resistant to corrosion, wear, and physical damage  or if
       they improve the general operation or performance  of  the system or component.  Proposed
       variations  shall be accepted by the testing agency prior  to use.  Systems  with components or
       functions  covered under existing NSF standards or criteria shall comply with those applicable
       requirements. •     *

•1.2    ALTERNATE MATERIALS:  If specific  materials   are mentioned, other materials equally
       satisfactory from the standpoint of performance and sanitation that meet the requirements of the
       standard shall be acceptable.

 1.3   REVIEWS AND REVISIONS: A. complete review of the standard shall be conducted at least every
      five years. These reviews are to be conducted by representatives from the industry, public health
      and user groups of the NSF Joint Committee on Drinking Water Treatment Units.


                                SECTIONS.  DEFINITIONS

2.0   ACCESSIBLE:   Fabricated to be exposed for cleaning and inspection  using simple tools
      (screwdriver, pliers, open-end wrench).   >
              i         '       v     -    .         . ' •      .     : -  t
      2.0.1 READILY ACCESSIBLE:' Fabricated to be exposed for cleaning and inspection without
           using tools.    •
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  Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.6  ANSl/NSF STANDARD 55-1991 (CONTINUED)

 2.1   CHALLENGE WATER:  The stream entering a component, system, or process.

 2.2   CLASS A SYSTEMS: Systems qapable of producing an ultraviolet dosage at the failsafe setpoint )
      equivalent to a dosage of 38,000 uW-sec/cm2.

 2.3   CLASS B SYSTEMS: Systems capable of producing an ultraviolet dosage equivalent to" a dosage
      of 16,000 jiW-sec/cm2 at 70 percent of the ultraviolet lamp normal output or at the failsafe point.

 2.4   CORROSION RESISTANT MATERIAL: Capable of maintaining original surface characteristics
      under prolonged contact with the use environment.

 2.5   DISINFECTION:   The action of removing, killing, or inactivating all types  of disease-causing
      microorganisms to render contaminated water safe for drinking.

 2.6   DRINKING WATER: Water intended for human consumption.

 2.7   EFFLUENT WATER: The stream emerging from a unit, system, or process.

 2.8   FAILSAFE SET. POINT:  The point at which the ultraviolet sensor activates the alarm.

 2.9   FLOW  CONTROL: An automatic flow control device which limits flow over a pressure range to
      the specified flow rate for the system or component.

 2.10  JOINING MATERIAL:  Any substance used to produce a tight joint; e.g., solvent cements,
      adhesives; or elastomeric seals.

 2.11   NORMAL OUTPUT (CLASS B  SYSTEMS): The UV dosage provided by the ultraviolet lamp
      after a 100 hour conditioning period.

 2.12  POINT-OF-ENTRY SYSTEMS:.  A system used to treat all or part of the water for the facility at
      the point of entry. For Class A systems a/acility shall be considered a single  family dwelling.

 2.13   POINT-OF-USE SYSTEMS: A system used to treat the water at a single tap or multi-taps, but not
      for the entire facility.           .                            ,                      ,

 2.14  REMOVABLE: Fabricated to be taken away from the system or component us.ing simple tools
      (screwdriver, pliers, open-end wrench, etc.).

      2.14.1     READILY (OR EASILY) REMOVABLE: Fabricated to be taken away from the main
                system or component without using tools.            .

 2.15   SENSITIVITY CALIBRATION: A measured level of spore and/or yeast inactivation resulting from
      the specified ultraviolet dose.  (Term is synonymous with UV sensitivity.)         ,          '•  ,

2.16   TOXIC: Having an adverse physiological effect on humans.

2.17   TURBIDITY:  A condition caused by the presence of suspended and/or colloidal matter, which
      results in the scattering and/or absorption of  light rays.


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  Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

  D.6  ANSi/NSF STANDARD 55-1991 (CONTINUED)

  2.18  ULTRAVIOLET SENSOR:  The  physical sensing system used to measure the intensity of
       ultraviolet light (225-300 Nanometers [nm]) transmitted.

  2.19  ULTRAVIOLET COMPONENT: the ultraviolet treatment lamp of an ultraviolet system.

  2.20 ' WASTEWATER:  Blackwaste and  grey waste generated from residences, commercial buildings,
       industrial plants, and institutions, and the water or medium used to transport it.

       2.20.1      BLACKWASTE:  Human and/or animal body waste, toilet paper, and any other
                  material intended to be deposited in and discharged therefrom a receptacle designed
             ;._    to receive urine and/or feces.

       2.20.2      GREYWASTE:  Waste materials,  exclusive of urine,  feces,  or industrial waste,
                  deposited in and discharged therefrom plumbing Fixtures found hi  residences'
                  commercial buildings, industrial plants, and institutions.


                                 SECTIONS. MATERIALS

 3.6    GENERAL: Materials in contact with water shall not impart undesirable taste, odor, color, and/or
       toxic substances to the water when tested and evaluated in accordance with Annex A.  Materials
       used in me construction of systems or components shall be capable of withstanding exposure to the
       intended use environment. Materials exposed to ultraviolet irradiation shall be formulated to resist
       deterioration and shall not impart undesirable tastes, odor, color, and/or toxic chemicals to the water i
      upon irradiation.                   ,     ,

 3.1   TEMPERATURE RESISTANCE: Systems and/or components shall be constructed of materials
      suitable to withstand temperatures generated during sustained periods of no water use.

 3.2   CORRODIBLE MATERIALS-:  Corrpdible materials shall be provided with a corrosion resistant.
      protective coating completely covering all wetted surfaces.

 3.3   GASKETS, O-RINGS, SHAFT SEALS, AND PACKING MATERIALS:  Gaskets, o-rings, shaft
      seals, and:packing materials shall conform to the applicable requirements of Item 3^0.

 3.4   DISSIMILAR METALS:    Dissimilar metals not  normally considered  compatible on  the
      electromotive scale shall not be in direct contact.

 3.5   INSULATING FITTINGS: Insulating fittings shall be provided when materials are not compatible
      on the electromotive scale with adjoining fittings or parts.                            '

 3.6   PLASTICS: If plastics are exposed to UV light, the manufacturer shall provide data to substantiate
      that the plastics meet the requirements of Items 3.0 and 3.1.

3.7   SOLDER:  Solder and fluxes on water contact surfaces shall be hard solder and shall conform to
      the requirements of Item 3.0.  Lead based solders (0.2% lead or greater) shall not be used.
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 Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.6  ANSI/NSF STANDARD 55-1991 (CONTINUED)

 3.8   WELDING: Welded seams and deposited Weld material shall meet the requirements of Items 3.0
      and 3.4.


                       SECTION 4. DESIGN AND CONSTRUCTION

 4.0   GENERAL:  A  system  or component evaluated under this  standard shall be designed >and
      constructed so that its intended purpose will be accomplished when installed and operated according
      to the manufacturer's instructions. (Components shall not be adversely affected by the normal
      environment to which they are  subjected.  Normal environment shall include usual vibration, shock,
      climate condition, and cleaning procedures as prescribed by the manufacturer.   Systems and
      components shall be designed to eliminate UV light exposure to humans when  operated and
      serviced according to manufacturer's recommendation.

 4.1   LAMP OPERATION INDICATION: The UV system or component shall be provided with a visual
      means to verify electrical operation of all lamps.

 4.2   UV LAMP ASSEMBLIES: UV lamp assemblies shall be designed to be insulated from direct
      contact with the influent water. If the UV lamps or assemblies are intended to be replaced,'they
      shall be removable.

 4.3   FLOW CONTROL: An automatic fixed flow rate control shall be provided to prevent flow above
      the manufacturer's maximum rated flow over the manufacturer's recommended operating pressure
      range.                              •                        .

 4.4   PERFORMANCE INDICATION: Class A systems shall be equipped with an UV sensor to monitor
      UV transmission or intensity through the water during operation. A visual and/or auditory alarm
      shall be used to indicate ineffective operation. A system that terminates discharge when ineffective
      operation occurs shall be considered as meeting this requirement.  Class B systems or components
    "  are exempt from these requirements. If an alarm is provided on a Class B system to measure UV
      transmission the alarm shall comply with Item 4.4.1.        .   .

      4.4.1 The alarm shall operate for at least 100 on-off cycles when tested in accordance with Annex
           F-

4.5   ELECTRICAL REQUIREMENTS: Systems and components shall be accepted by a recognized
      electrical testing laboratory (Underwriters Laboratories  [UL] or equivalent)  when applicable.
      Certification of conformance shall be provided by the manufacturer.

4.6   WORKING PRESSURE:  The systems, and all components subject to line pressure, shall be
      designed for a working pressure of at least 689 kPa (100 psig).

4.7   LAMP REPLACEMENT (CLASS B SYSTEMS):  The recommended lamp replacement intervals
      for Class B  systems shall be verified by submittal of intensity vs. time curves. The intensity shall
      be measured at 254 nm at a distance of 1 m (3.3 ft,).

4.8   MAINTENANCE: The system or component shall be designed to be accessible for cleaning and
      replacement of the lamp jackets  and  sensor  window/lens provided, on  the systems.    The


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   Appendix P.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

  D.6   ANSI/NSF STANDARD 55-1991 (CONTINUED)

        manufacturer's cleaning procedures shall result in thorough cleaning of the system.  The treatment
        chamber shall be designed so that at least one end can be dismounted for cleaning.


                                SECTIONS.  PERFORMANCE

  5.0    GENERAL: Systems and components covered under this standard shall be designed to meet the
        microbiological performance requirements at the manufacturer's recommended operating pressures
        and flow rates.

  5.1   STRUCTURAL INTEGRITY PERFORMANCE:  Systems and components shall comply with the
       following, structural integrity performance requirements when tested in accordance with Annex E.

       5.1.1 Units with permanent pressure vessels less than 203 mm (8 in.) in diameter subject to line
            pressure shall conform to the foUowing requirements:

           "•     Complete assemblies shall withstand a hydrostatic test pressure of 2.4  times  the
                  working pressure or 1654 kPa,(240 psig), whichever is greater,  for a period of 15
                  minutes without leakage of water from the unit..                -   -    .

                  Metallic pressure vessels shall withstand a hydrostatic test pressure of 24 times the
                  working pressure or 1654 kPa (240 psig), whichever is greater,  for a  peri9d of 15
                  minutes without excessive permanent distortion, defined as an  increase  in  vessel
                  circumference more than 0.2 percent of the original circumference or top or bottom
                  head deflection more than 0.5 rpercent of the tank diameter.

            *      Nonmetallic pressure vessels  shall have a burst pressure of at least 4.0 times the
                  .working pressure or 2756 kPa (400 psig), whichever is greater.

                  Nonmetallic pressure vessels shall be watertight at 1034 kpa (150 psig) and after a
                  minimum  of 100,000 pressure cycles of 0 to 1034 kPa (0 to 150 psie) at 20 ± 2 5° C
                  (68±5°F).          .  "   '   .  •      ,

                  Valves and controls subject to line pressure shall be watertight at 1034 kPa (150 psig)
                  and after a minimum of  100,000 pressure cycles of 0 to 1034 kPa (0 to 150 psig) at
                  20 ± 2.5°  C (68 ± 5° F).                                        ,              -

      5.1.2  Units with permanent pressure vessels 203 mm (8 in.) and greater in diameter subject to line
            pressure shall conform to the following requirements:

            •     Complete  assemblies shall withstand a hydrostatic test pressure of 1.5 times the
                 working pressure or 1034 kPa (15p psig), whichever is .greater, for a period  of 15
                 minutes without leakage of water from the unit.

                 Metallic pressure vessels shall withstand a hydrostatic test pressure of 1.5 times the
                 working pressure or 1034 kPa (150 psig), whichever is greater, for a period of 15
                 minutes without excessive permanent distortion,  defined as  an  increase  in tank
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  Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.6  ANSI/NSF STANDARD 55-1991 (CONTINUED)

                  circumference more than 0.2 percent of the original circumference, or top or bottom
                  head deflection more than 0.5 percent of the vessel diameter.

            •     Nonmetallic pressure  vessels  shall have a burst pressure of at least 4.0 times the
                  working pressure or 2756 kPa (400 psig), whichever is greater.

       5.1.3 DISPOSABLE PRESSURE  VESSELS:  Disposable pressure vessels and. all replaceable
            components subject to line pressure shall meet the following requirements:

            •     Disposal pressure vessels and replaceable components shall withstand a hydrostatic test
                  pressure of 2.4 times  the working pressure or 1654 kPa (240 psig), whichever is
                  greater, for a period of 15 minutes without leakage of water from the unit.

            •     Disposable pressure vessels and replaceable components shall be water-tight and show ,
                  no evidence of failure after being subjected to 10,000 pressure cycles of 0 to 1034 kPa
                  (0 to 150 psig) at 20 ± 2.5° C (68 ± 5° F).

      5.1.4 UNITS DESIGNED FOR OPEN DISCHARGE:   All  components subject to pressure,
            including connecting tubing where required, shall meet the following requirements:

            •     Complete assemblies,  with the  outlet  plugged, shall  withstand a hydrostatic test
                  pressure of 1.2 times the working pressure or 867 kPa (120 psig), whichever is greater,
                  for a period of 15 minutes without leakage of water from the unit.
                                                                      I

            •     Complete assemblies, with the outlet plugged, shall be watertight at 344 kPa (50 psig)
                  after a minimum of 10,000 cycles of 0 to 344 kPa (0 to 150 psig) at 20 ± 2.5° C (68
                  ±5°F).

      5.1.5  PORTABLE UNITS:  Portable units, not designed for direct pressurized connection to a
            water line, shall meet the following hydrostatic requirements:
                                                  f
            •     Units designed to be pressurized by the user shall withstand a hydrostatic test pressure
                 of 1.5 times the working pressure for a period of 15 minutes without leakage of water
              .  from the unit.             .                                     ,         •   . •

            •     Units designed for only atmospheric (open) pressure or only  gravity flow  shall be
                 exempted from hydrostatic tests, but shall be water-tight in normal use.

5.2   SENSmVITY CALIBRATION: Spore and/or yeast sensitivity calibration (UV sensitivity) shall
      be determined in accordance with Annex B prior to conducting performance testing in accordance
      with Annex C or D.

5.3   DISINFECTION PERFORMANCE: Disinfection performance for a-Class A system shall provide
      a minimum UV dose equivalent to 38,000 uW-sec/cm2 at the fail-safe point, as determined by the
      inactivation of spores whose sensitivity has been determined in Item 5.2,

5.4   MICROBIAL REDUCTION PERFORMANCE: Microbial reduction performance for a  Class B
      system shall provide a minimum UV dose equivalent to 16,000 uW-sec/cm2 at 70 percent of the

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   Appendix P., Regufations and Standards for Drinking Water Disinfection Using Ultraviolet Light

   D.6  ANSI/NSF STANDARD 55-1991 (CONTINUED)

        UV lamps'normal output or at the fail-s^fe point as determined by the inactivation of yeast whose
        sensitivity has been determined in Item 5.2.-  .'


                       SECTION 6. mSTRUCTION AND INFORMATION

  6.0   OPERATION; MAINTENANCE, AND  INSTALLATION INSTRUCTIONS:  instructions for
        installation, operation, maintenance, and initiation of service shall be provided with each system or
        component.  Installation instructions shall note the need for compliance with state and local model
        laws and regulations.  Supply sources for expendable components and supplies for the system or
        component shall  be clearly stated. A manual shall be provided which includes drawings and parts
        lists for easy identification and ordering of replacement parts and shall include:

             Model number and class designation

        •     Statement  of applications:       ~

             This Class  A system conforms to NSF Standard 55 for the disinfection of microbiologicallv
             contaminated water that meets all other public health standards. The system is not intended
             for the treatment of water that has an obvious contamination source, such as raw sewage; nor
             is the system intended to convert wastewater to microbiologically safe drinking water 'The
             system is .intended to be installed on visually clear water (not colored,  cloudy  or turbid
             water).  If this system is used for the treatment of surface, waters a prefilter found to be in"
             compliance for cyst reduction under ANSI/NSF Standard 53:  Drinking Water treatment
             Units - Health Effects shall be installed upstream of the system.

            NSF Standard 55 defines wastewater to include human and/or animal body waste 'toilet
            paper, and  any other material intended to be deposited in a receptacle designed to receive
            unne and/or feces (blackwaste); and other waste materials deposited in plumbing fixtures
            (greywaste).

            OR                                                            :

            This Class B system or component conforms to NSF Standard 55, and contains ultraviolet
           ) lamps that require replacement at intervals in accordance with the manufacturer's instructions
            The system is  designed for the supplemental  bactericidal treatment of either treated and
            disinfected public drinking water or other drinking water which has been tested and deemed
            acceptable for human consumption by  the state or local health agency having jurisdiction
            The system is designed to  reduce  normally occurring  non-pathogenic or nuisance
            microorganisms only. Class B Systems are not intended for treatment of contaminated water.

 •     •     Model number of UV lamp
      •     Use limitations
      •     Cleaning instructions
      •    Maximum and minimum flow rates
  ;    •    Recommended frequency for the replacement of UV  lamps (Class B  systems)
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 Appendix D. Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

D.6  ANSI/NSF STANDARD 55-1991 (CONTINUED)

6.1   DATA PLATE: A data plate or plates shall be clearly and permanently affixed to the system or
      component in a readily accessible location and shall contain:

      •    Manufacturer's name and address
      •    Model number and class designation
      •    Model number of UV lamps
      •    Maximum operating feed water temperature in degrees C (degrees F)
      •    Applicable warning signs                                                         ;.
      •    Use limitations statement:  "See instruction manual for use conditions."
      •    Maximum rated operating pressure in kPa (psi)
      •    Maximum flow rate in L/min (gpm or gpd)
      •    Operational volts, amperage, and Hertz of system
      •    Recommended frequency for the replacement of UV lamps (Class B systems)
      •    The following applicable statement:

           CLASS A SYSTEM: Conforms to NSF Standard 55 for the disinfection of microbiologically
           contaminated waster that meets all other public health standards. The system is not intended
           for the treatment of water that has an obvious contamination source, such as raw sewage; nor
           is the system intended to convert wastewater to microbiologically safe drinking water.

           ,OR

           CLASS B SYSTEM: The system or component conforms to NSF Standard 55, and contains
           ultraviolet lamp(s) that require replacement at intervals in accordance with the manufacturer's
           instructions.  The system is intended for the supplemental bactericidal treatment of either
           treated and disinfected public drinking water or other drinking water that has been tested and
           deemed acceptable for human consumption by the state or local health agency  having
           jurisdiction.   The  system is designed to reduce normally  occurring non-pathogenic of
           nuisance microorganisms only. Class B Systems 'are not intended for the disinfection of
           contaminated water.

6.2   SALES FACTS SHEET:  A sales fact sheet shall be available to the purchasers and shall  include
      the following information:

      •    Model number and class designation

      •    Statement of applications:

           This Class A system conforms to NSF Standard 55 for the disinfection of microbiologically
           contaminated waster that meets all other public health standards. The system is not intended
           for the treatment of water that has an obvious contamination Source, such as raw sewage; nor
           is the system intended to convert wastewater to microbiologically safe drinking water. The
           system is intended to be installed on  visually clear water (not colored,  cloudy, or turbid
           water).  If this system is used for the treatment of surface waters a prefilter found to be in
           compliance for cyst reduction under ANSI/NSF Standard-53: Drinking Water Treatment Units
           - Health Effects shall be installed upstream of the system.
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  Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

 D.6  ANSI/NSF STANDARD 55-1991 (CONTINUED)

            NSF Standard 55 defines wastewater to Delude human and/or animal body waste, toilet
            paper, and any other material intended to be deposited in a receptacle designed to receive
            urine and/or feces (blackwaste); and  other waste materials deposited in plumbing fixtures
           , (greywaste).

                  OR

            This Class B system or component conforms to NSF Standard 55, and contains ultraviolet
            lamps that require replacement at intervals in accordance with the manufacturer's instructions.
            The system is designed for the supplemental bactericidal treatment of either treated and
            disinfected public drinking water or other drinking water which has been tested and deemed
            acceptable for human consumption by the state or local health agency having jurisdiction.
            The system is designed  to  reduce normally occurring  non-pathogenic  or  nuisance
            microorganisms only. Class B Systems are not intended for treatment of contaminated water.

      •     Manufacturer's name and address

      •     Rated service flow rate in L/min (gpm or gpd)                                v

      •     Pressure drop of unit in kPa (psig) at rated flow.

      •  „  Electrical characteristics, volts, amperage, and Hertz.  Recommended service life of UV
            lamps

      •     Maximum and minimum operating pressure in kPa (psig).

     '» •    Maximum operating feed water temperature in degrees C (degrees F).

      •     Use limitations

            Recommended frequency for the replacement of UV lamps (Class B systems)
UV Light Disinfection Technology in
Drinking Water Application—An Overview    D-29.                     Final—September 1996
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   Appendix D.  Regulations and Standards for Drinking Water Disinfection Using Ultraviolet Light

  D.6  ANSVNSF STANDARD 55-1991 (CONTINUED)

      'The  preface  and pages 1  through  9 of ANSI/NSF  Standard 55-1991  "Ultraviolet
       Microbiological Water Treatment Systems" are  reprinted with the permission of NSF
       International.  To assure you have the complete and current standard, please contact:

            NSF International
            3475 Plymouth Road                                      •
            P.O. Box 130140
            Ann Arbor, MI  48113-0140
            1-800-NSF-MARK
            World Wide Web Address: http://www.nsf.org
            &-Mail Address:  info@nsf.org
UV Light Disinfection Technology in
Drinking Water Application—An Overview    D-30                     Final—September 1996
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