BIOLOGICAL WASTE TREATMENT
USING. THE BIOLAC SYSTEM
A TECHNICAL NOTE
September 1986
Prepared For:
U.S. Environmental Protection Agency
Off ice-, of. Municipal Pollution Control
Municipal. Facilities Division
. 401 M Street,, S.W.
Washington, D.C., 20460
Prepared By:
Environmental Resources Management/ Inc.
. 999 West Chester Pike
West Chester/ Pennsylvania,- 19382
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ACKNOWLEDGMENTS
ERM wishes to thank Charles Morgan of the Parkson Corporation
(Fort Lauderdale/ Florida) and Carl Janson of Riordan Mater-
ials/ Haverford/ Pennsylvania* for their willingness to discuss
the characteristics/ design/ and performance of the BIOLAC
system.
This report is a technical assessment of the BIOLAC System/
based entirely on data obtained from the manufacturer of the
BIOLAC system and on accepted theories of biological treatment.
It was prepared for the Office of Municipal Pollution Control
under contract number 68-01-7108. The information was compiled
to assist those involved in the innovative and alternative
technology program. This document has not been subjected to the
agency's peer and administrative reviews/ and therefore does not
necessarily reflect the views of the agency.
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TABLE OP CONTENTS
Page
I. Description of Process and Systea Design 1
A. Process and Process Options 1
B. Existing and Proposed Installations 6
C. Manufacturer's Claims 6
II. Evaluation of Design Procedure - Hew
Construction and Retrofits 7
A. Design Procedure Recommended by the
Manufacturer/Supplier 7
B. Comments on the Design Procedure 8
III. Evaluation of Systev Perfornance 8
A. Manufacturer's Claims 8
B. Availability and Suitability of Existing
Operations Data 8
IV. Level of Confidence in the BIOLAC Treatnent
Concept 9
A. BIOLAC Process Innovations 9
B. Basis for Assigning a Good Level of
Confidence 9
C. Benefits of Strengthening Certain Design
Parameters Via a Field Test 10
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I. Description of Process and Syatea Design
A. Process and Procesa Options
BIOLAC is a complete biological treatment system for municipal
and industrial wastewaters. BIOLAC/ an acronym for "Biological
Wastewater Treatment System using Aeration £hains"/ consists of
an earthen basin/ or lagoon/ with floating aeration chains
intended to aerate and mix the wastewater. Additional aerated or
unaerated polishing lagoons and a final channel for nutrient
uptake are optional. The design goal is direct discharge of
clarified effluent of secondary treatment quality or better to a
receiving stream. Some wastewaters may require pretreatment or
post-chlorination. Parkson Corporation/ which markets BIOLAC/
offers two systems for different applications/ as shown in
Figure 1 and described below:
BIOLAC-L. An aerobic/ flow-through system for the biological
treatment of domestic wastewater with organic loadings of 30 to
300 pounds of BOD per day. In this system/ wastewater flows from
a first-stage lagoon into a second-stage polishing lagoon with a
quiescent solids settling zone at one end/ and then into an
optional channel containing nutrient-removing aquatic plants.
Polishing consists mostly of additional solids settling.
BIOLAC-R. An extended aeration/activated sludge system for the
treatment of domestic and/or industrial wastewaters with organic
loadings of 300 to 30/000 pounds of BOD per day. Unlike
BIOLAC-L, BIOLAC-R features an integral concrete clarifier with
sludge return at the end o'f the first-stage lagoon/ and a sludge
storage pond with decant to the first-stage lagoon. The stored
sludge is claimed to develop a five to ten percent solids
content.
There are notable differences between the design/ intended
application and performance of BIOLAC-L and BIOLAC-R. For
instance/ BIOLAC-L is designed to be a flow-through system
without appreciable solids retention time/ while BIOLAC-R is
designed to be an extended aeration system with 20 to 30 days of
solids retention time. Also/ while BIOLAC-L is intended for
treatment of domestic wastewaters with relatively low organic
loading/ BIOLAC-R is intended for domestic or industrial waste-
waters of much higher organic loadings. In addition/ BIOLAC-R
is capable of removing greater amounts of BOD/ yet maintaining a
lower biological solids concentration through extended aeration.
In contrast/ BIOLAC-L is capable of relatively low BOD removal
and is designed to maintain a certain hydraulic detention time/
rather than a particular biological solids retention time. The
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Influent
Figure 1
Schematic of a BIOLAC Treatment System
(Adapted From a Parkson Corporation Product Brochure) Effluent
T
c
Optional Oxidation Ditch With Aquatic Plants
Sludge' Return ,., Sludge Wasting
,r |_; :-x
Second-Stage Lagoon
For Polishing
KEY
_*_}Biolac-R Only
1 - Operations Building
with Automatic
Bar Screen
2 - Optional Gnt
Chamber
3 - Flow Measuring
Equipment
4 - Centrally Located
Blowers
5 - Aerated Chains
6 - Floating Overflow
* 7 - Integral Clanfier
(Concrete)
8 - Sampling Point
9 - Floating Plaslicized
Cloth Wall With
Openings for
Wastewater Flow
*10 - Sludge Pond
with Decant Return
Not To Scale
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manufacturer believes that the unique features of BIOLAC-R are
more applicable for meeting the more stringent discharge
limitations placed on domestic and industrial wastewaters.
Aeration Chains. Both the BIOLAC-L and BIOLAC-R systems are
equipped with floating "aeration chains"/ shown in Figure 2, for
mixing and aeration. Wyss" flexible sheath diffusers are sus-
pended from the floats of these aerated chains/ which are
anchored to the edge of the lagoon by stainless steel cables.
1. Design Parameters and Assumptions
BIOLAC design parameters are similar to those of conventional
biological systems. Table 1 compares typical design criteria for
BIOLAC-L with conventional flow-through aerated lagoons and
BIOLAC-R with extended aeration/activated sludge systems. Table
1 shows that the BIOLAC-L system design/ like the aerated lagoon/
is based on hydraulic detention time rather than organic loading
or biomass requirements. The six to fifteen days of detention
time recommended for BIOLAC-L is a somewhat higher range than the
typical aerated lagoon detention time of three to ten days. In
addition/ BIOLAC's manufacturer predicts that power requirements
for mixing BIOLAC aeration basins are much less than the typical
ones for mixing conventional aerated and extended aeration
lagoons/ as shown in Table 1.
The conventional extended aeration lagoon is designed for an F:N
ratio of between 0.05 and 0.15 pounds of BOD per pound of MLVSS/
while the BIOLAC-R system is designed for a ratio of 0.03 to
0.10 in order to minimize sludge yields. The recommended MLSS
concentration range is also somewhat lower for BIOLAC-R than for
the conventional system. The manufacturer claims that
nitrification will also occur in the extended aeration basin
(first stage lagoon).
2. Typical Operating Conditions
For the BIOLAC aeration system/ Parkson suggests a minimum
standard oxygen transfer rate of four to five pounds of oxygen
per horsepower-hour/ a minimum of 0.08 to 0.12 aerator horsepower
per 1/000 cubic feet of lagoon volume for mixing/ ten-to fifty-
foot spacing between aeration chains/ and 9 to 30 inches of
clearance for diffusers above the bottom of the lagoon. Each
float assembly is equipped with either two or four Wyss" flexible
sheath diffusers/ each of which provides one to five standard
cubic feet of air per minute. Four diffusers could thus provide
up to twenty standard cubic feet of air per minute. Aeration
chains are typically between 30 and 400 feet in length. The EPA
document/ EPA 625/8-85-010/ indicates that EPA has studied the
Wyss" diffusers and classified them as fine bubble diffusers. The
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Figure 2
Schematic of a BIOLAC Aerated Chain System
Float Assembly
Hose Clamp
D
Air Pipe
Downcoming Air Tube
o .
° - °..o
O ma a
Water Surface
Two or Four "Wyss" Diffusers
' Per Float Assembly
9" - 30"
iw^vt:**^7Viv;;i:^
Float
* -^ ^ * * ^
Water Surface
"Wyss" Flex-a-Tube
Flexible Sheath
Not to Scale
^:V-r,*^-?.:-?i'--'''?'-'.
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Ul
TABLE 1
MANUFACTURER'S DESIGN CRITERIA FOR BIOLAC SYSTEMS
IN COMPARISON WITH AERATED LAGOONS AND
EXTENDED AERATION/ACTIVATED SLUDGE
Design Criteria
Parameter
Lagoon Depth/ Feet
Hydraulic Detention Time/ Days
Food: Microorganism Ratio/
Ib. BODs/day/lb. MLVSS
BCD Removal/ %
HLSS, mg/1
Solids Retention Tine (SRT) days
Effluent TSS, mg/1
Aeration Basin Mixing Require-
ment (HP/MG of basin volume)*1'
Aerated Lagoon*
6 to 20
3 to 10
Not Applicable
80 to 95%
NR
3 to 6
260 to 300
70 to 130<2)
Biolac-L**(l)
8 to 20
6 to 15
Not Applicable
90% / typically
NR
NR
NR
3-6 HP/MG
(Typical)
Extended Aeration/*
Activated Sludge
Not Applicable
.75 to 1.5
0.05 to 0.15
75 to 95%
3/000 to 6/000
20 to 30
20 to 30
130 to 200<2>
Biolac-R**(l)
8 to 20
1 to 2
0.03 to 0.10
99%, typical 1]
1,500 to 5,00(
50 to 70
NR
12 to 15 HP/MC
Sludge Recycle Ratio
Not Applicable
Not Applicable
0.75 to 1.50
Adjustable
NR: Not Reported
* Reference: MeteaIf and Eddy/ Inc., Wastewater Engineering, 1972.
** Reference: Parkson Corporation
1 Data from manufacturer, Parkson Corporation
2 Horsepower required for mixing, which is typically greater than that for oxygen demand in the systems noted.
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EPA report does not indicate/ however/ that the Wyss" diffusers
meet the ASCE criteria for fine bubble diffusers. When fully
charged with air/ the manufacturer notes/ the air bubbles
approach medium size.
3. Major Equipment
BIOLAC-L and BIOLAC-R systems both require air blowers/ aeration
system controls/ influent and effluent pumps/ and overflow weirs.
Temperature and pH recorders are optional. BIOLAC-R also re-
quires an integral clarifier/ a sludge airlift pump and possibly
a sludge wasting pump. Lagoon liners may be required to meet
environmental requirements.
B. Existing and Proposed Installations
Of the 100 BIOLAC systems operating in Europe/ performance data
are available for only three: BIOLAC-R systems located in
Konigslutter, Rot am See/ and Bielefeld/ West Germany. At ten
sites/ substitution of existing aeration systems with aeration
chains (a type of retrofit) has occurred. Site locations include
Franklin/ Ohio/ and Pierrepont Manor/ New York. Eight other
retrofits are planned for installation/ are currently being
installed/ or are in a start-up phase for the treatment of
domestic/ poultry/ industrial wastewater in the United States.
One BIOLAC-R project has been granted funding under the EPA's
Innovative/Alternative Program. It will be located in Columbiana/
Alabama (EPA Region IV).
C. Manufacturer's Claims
According to the Parkson Corporation/ the BIOLAC system is
applicable to any biodegradable wastewater and incorporates many
proven treatment processes in a highly efficient and innovative
way. Presently/ German BIOLAC installations treat food and
beverage industry as well as domestic wastewaters with organic
loadings ranging from 40 to 22/000 pounds per day of BOD and flow
rates ranging from 0.01 to 1.6 NGD. In comparison with conven-
tional extended aeration/activated sludge systems/ the BIOLAC
system is claimed to have greater system stability/ equal or
better BOD removal capability/ reduced sludge production and
greater nitrification (BIOLAC-R only)/ and lower construction!
operating/ and maintenance costs. The manufacturer attributes
these benefits to the longer design SRT used. Major advantages
cited are the efficient use of submerged/ flexible sheath
diffusers/ earthen lagoons/ and the system's ability to perform
at low organic loading rates and in cold climates.
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II- Evaluation of Design Procedure - Hew Construction and
Retrofita '
A.- Design Procedure Recoanended by the Manufacturer/
Supplier
Information on specific procedures used in the design of existing
plants was not available. However/ the manufacturer recommends a
design based on conventional parameters (source/ quality and flow
rate of wastewater/ the desired effluent quality) and the design
criteria indicated in Table 1. A treatability study is recom-
mended prior to design/ particularly for wastewaters with a
significant industrial component/ in order to optimize the system
design. Following system installation/ the manufacturer empha-
sizes the need to monitor the lagoons for dissolved oxygen/
temperature/ and pH/ as is advisable with any aerobic treatment
system. However/ the manufacturer believes that less monitoring
effort is needed than with conventional systems.
Generally/ for domestic wastewaters at less than 200/000 gpd a
BIOLAC-L system is recommended/ while BIOLAC-R is recommended for
higher municipal flows and industrial wastewaters. Each waste-
water should be evaluated for selection of the type of system to
be applied. To provide extended aeration and desired effluent
quality/ BIOLAC-R lagoons are designed to provide specific ranges
for hydraulic retention time/ food to microorganism ratio/ and
NLSS. The BIOLAC-R sludge storage pond is typically sized to
provide at least six months of storage to allow stored sludge to
dewater to a predicted five to ten percent solids.
Parkson does not provide'specifics on retrofitting an existing
lagoon/ but indicates that performance data for the lagoon will
determine whether its size is adequate for the intended treat-
ment. The manufacturer claims that a conventional lagoon can be
modified to resemble a BIOLAC system.
Replacement of existing surface aerators or fixed diffusers with
aerated chains is recommended to improve mixing/ lessen aeration
energy requirements (versus surface aerators and coarse bubble
diffusers)/ simplify maintenance and reduce maintenance costs.
For both new construction and retrofits/ the aeration chain
system is designed according to the selected lagoon depth/ the
wastewater quality and flow rate/ seasonal temperature fluctua-
tions/ and the oxygen demand of the wastewater. The required air
discharge pressure and blower capacity are determined from this
information and the design of the Wyss1" diffusers.
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The manufacturer claims that the aeration chains provide adequate
mixing at much less energy than that required for aeration and/
therefore/ the aeration system design is controlled by the
aeration requirements. This contrasts with the practice of
sizing conventional lagoon aeration systems on the basis of
mixing requirements.
The manufacturer recommends that the second lagoon be installed
in every BIOLAC system in order to provide additional buffering
capacity for handling peaks in organic concentrations and
hydraulic loads. The buffer is intended to reduce the level of
operator attention required.
B. CoMDenta on the Design Procedure
Since BIOLAC systems utilize conventional treatment processes and
are designed on the basis of well-established principles of
biological treatment/ their design procedure is correct in
theory. However/ since specific documentation on the design
procedures is not available/ further information is necessary to
verify the basis of the design. The use of submerged diffusers
should reduce drops in lagoon temperature. It is not clear how
much benefit is provided by the second aeration lagoon in
BIOLAC-R/ since about 95 percent of the treatment occurs in the
extended aeration lagoon.
III. Evaluation of System Performance
A. Manufacturer'a Claina
No opportunity was available to compare the manufacturer's claims
with reports from actual BIOLAC operators in Europe. The
manufacturer feels that the wide application of the BIOLAC in
Europe attests to its high performance. In addition/ two
BIOLAC-R and ten individual aeration chain systems have been
sold/ and will begin operating by mid-1987.
B. Availability and Suitability of Existing Operations
Data
More design and operational data are needed to fully evaluate the
BIOLAC treatment concept. For example/ only limited case
histories from three West German BIOLAC-R plants are available/
although they show high BOD removals and represent a wide range
of influent flows. None of the available operations data pertain
to BIOLAC-L plants/ and none include percent removals of suspend-
ed solids/ the degree of dewatering in the sludge settling ponds/
or performance during an entire winter or over the long term.
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Only one case history provided data for nitrification and COD
removals. Furthermore/ only a limited amount of design data (BOD
loadings and population equivalents) are available for comparing
specific BIOLAC designs to actual plant construction and perform-
ance.
IV. Level of Confidence in the BIOLAC TreatBent Concept
A. BIOLAC Process Innovations
The BIOLAC system employs several unproven design features.
These include:
1. The efficient use of submerged flexible sheath
diffusers in a large volume/ earthen lagoon
system/ which is predicted to increase oxygen
transfer efficiency and reduces capital cost;
2. The use of low F:M ratios and longer solids
retention times in an economical system (relative
to lagoons with conventional aeration systems)/
to produce a low-volume/ well-stabilized sludge
and to achieve process stability/ high BOD
removal/ and nitrification;
3. The use of integral clarifiers to reduce construc-
tion costs (BIOLAC-R only); and
4. The use of "aeration chains" to "sweep" the
lagoon/ reducing the mixing horsepower require-
ments. ' '
Critical design variables for BIOLAC are solids retention time/
hydraulic detention time/ organic loading/ and aeration horse-
power requirements.
B. Basis for Assigning a Good Level of Confidence
ERN can assign a good level of confidence to the theory of the
BIOLAC concept for the treatment of wastewater in the United
States. However/ due to incomplete design and operational data/
and the fact that as of September 1986, there are no operational
non-retrofit BIOLAC installations in the United States/ use of
theBIOLAC system would carry "relatively high technological
risk" according to guidelines issued by EPA. Therefore the
BIOLAC system would fall under "Area A: Field Test to Verify
Design for Innovative Designation/" of Figure 1: Window of Risk/
as shown in the "Guidance on Designating Projects as Innovative,"
(USEPA/ Office of Municipal Pollution Control). The recent EPA
grant for a BIOLAC-R system in Alabama may serve as this field
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test. If so/ successful operation of this BIOLAC-R may allow
BIOLAC to be later designated as having the potential for further
designation as Innovative. However/ the fact that there are over
100 operating systems in Europe is a very strong indication that
the system could have successful application in the United
States. In addition/ two complete BIOLAC-R and ten individual
aeration chain systems are scheduled for start-up in mid-1987.
Furthermore/ no new treatment theories are apparently used in the
BIOLAC design; all components of the BIOLAC system appear to be
designed on the basis of accepted/ conventional theories of
biological treatment.
No final conclusion about the performance of the aeration chain
systems can be made. The manufacturer reports no mechanical
failures to date but recommends an annual inspection of the
aeration system.
C. Benefits of Strengthening Certain Parameters Via a
Field Teat
Field tests would improve BIOLAC design guidelines for similat
treatment applications/ and thereby increase the probability that
such a system would perform well and not require additional
expenditures for system modifications. Design criteria could be
strengthened for particular wastewater types and climates/ and
the system components could be sized more accurately.
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