PBS6-173630
THE LUBBOCK LAND TREATMENT SYSTEM RESEARCH AND
DEMONSTRATION PROJECT. VOLUME V: EXECUTIVE SUMMARY
Lubbock Christian College
Lubbock, TX
Feb 86
U.S. DEPARTMENT OF COMMERCE
National Technical Information Service
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&EPA
United States
Environmental Protection
Agency
• Robert S. Kerr Environmental
Research Laboratory
Ada OK 74820
EPA/600/2-86/027e
February 1986
Research and Development
The Lubbock Land
Treatment System
Research and
Demonstration
Project:
Volume V.
Executive Summary
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
1. REPORT NO.
EPA/600/2-86/027e
2.
3. RECIPIENT'S ACCESSIOf*NO.
173jb30/J.S
4. TITLE AND SUBTITLE
THE LUBBOCK LAND TREATMENT SYSTEM RESEARCH
AND DEMONSTRATION PROJECT
VOLUME V: EXECUTIVE SUMMARY
5. REPORT DATE
February 1986
6. PERFORMING ORGANIZATION CODE
>B> Georgej N-L> Altman, D.E. Camann,. B.J.
Claborn, P.J. Graham, M.N. Guntzel, H.J. Harding, R.B.
Harrist. A.H. Holauin. K.T. Kimball. N.A. Klein, cont-lii
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Lubbock Christian College Institute of
Water Research
Lubbock, TX 79407
10. PROGRAM ELEMENT NO.
CAZB1B
11. CONTRACT/GRANT NO.
CS-806204 and
CR-807501
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Robert S. Kerr Environmental Research Laboratory
P.O. Box 1198
Ada, OK 74820
13. TYPE OF REPORT AND PERIOD COVERED
Final 11/27/78 - 12/31/85
14. SPONSORING AGENCY CODE
EPA/600/15 .
15.SUPPLEMENTARY NOTES D.B. Leftwich, R.L. Mason, B.E. Moore, R.L.. Northrup, C. Becke^
Popescu, R.H. Ramsay, C.A. Sorber, R.M. Sweazy
Project Officers; Lowell E. Leach and Walter Jakubowski
16. ABSTRACT
The Lubbock Land Treatment System Research and Demonstration Project, funded
by Congress in 1978 (H.R. 9375), was designed to address the various issues
concerning the use of s-low rate land application of municipal wastewater. The
project involved the 1) physical expansion of overloaded 40 year old Lubbock
slow rate land treatment system; 2) characterization of the chemical, biological
and physical conditions of the ground water, soils and crops prior to and during
irrigation with secondary treated municipal wastewater; 3) evaluation of the.
health effects associated with the slow rate land application of secondary
effluent and 4) assessment of the effects of. hydraulic, nutrient and salt mass
loadings on crops, soil and percolate.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
13. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
125-
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
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EPA/600/2-86/027e
February 1986
THE LUBBOCK LAND TREATMENT SYSTEM
RESEARCH AND DEMONSTRATION PROJECT
VOLUME V
Executive Summary
by
D. B. George1, N. L. Altman5, D. E. Camann2, B. J. Claborn7,
P. J. Graham5, M. N. Guntzel\ H. 0. Harding2,
R. B. Harrist6. A. H. Holguin6, K. T. Kimball2,' N. A. Klein1,
D. B. Leftwichl, R. L. Mason2, B. E. Moore5, R. L. Northrup5,
C. Becker Popescu5, R. H. Ramsey7, C. A. Sorbet5, R. M. Sweazy7
1Lubbock Christian College Institute of Water Research, Lubbock, TX 79407
2Southwest Research Institute, San Antonio, TX 78284
^University of Illinois at Chicago, Chicago, IL 60680
^University of Texas at San Antonio, San Antonio, TX 79285
^University of Texas at Austin, Austin, TX 78712
6University of Texas School of Public Health, Houston, TX 77025
7Texas Tech University, Lubbock, TX 79409
EPA COOPERATIVE AGREEMENT CS806204
and CR807501
Project Officers
Lowell E. Leach
Jack L. Witherow
H. George Keeler
Curtis C. Harlin
Wastewater Management Branch
R. S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
Walter Jakubowski
Toxicology and Microbiology Division
Health Effects Research Laboratory
Cincinnati,Ohio 45268
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
/•a-
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DISCLAIMER
The information in this document has been funded in
part by the United States Environmental Protection Agency
under assistance agreement No. CS806204 to the Lubbock
Christian College Institute of Water Research and by the
Health Effects Research Laboratory, United States Environ-
mental Protection Agency under CR-807501 to Southwest
Research Institute. It has been subjected to the Agency's
peer and administrative review and has been approved for
publication as an EPA document. Mention of trade names or
commercial products does not constitute endorsement or
recommendation for use.
11
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FOREWORD
The U.S. Evironmental Protection Agency was established to coordinate
the administration of major Federal programs designed to protect the qual-
ity of our environment.
An important part of the Agency's effort involves the search for
information about. environmental problems, management" techniques, and new
technologies through which optimum use of the Nation's land and water
resources can be assured and the threat pollution poses to the welfare of
the American people can be minimized.
The U.S. Environmental Protection Agency's Office of Research and
Development conducts this search through a nationwide network of research
facilities. As one of these facilities, the Robert S. Kerr Environmental
Research Laboratory is responsible for the management of programs including
the development and demonstration of soil and other natural systems for the
treatment and management of municipal wastewaters.
The slow rate land treatment process of municipal wastewaters uses the
unsaturated soil profile and agricultural crops managed as the treatment
media. The Lubbock Land Treatment System Research and Demonstration Pro-
gram, funded by Congress in 1978 (H.R. 9375) was designed to address the
various issues limiting the use of slow rate land application of municipal
wastewater. The project involved expansion of the Lubbock Land Treatment
System to 2,967 hectares; characterization of the chemical, biological and
physical condition of the ground water, soils and crops prior to and during
irrigation with secondary treated municipal wastewater; and evaluation of
the U.S. Environmental Protection Agency's design criteria for slow rate
land application. Results demonstrate that, where such systems are cor-
rectly designed and operated, they can be cost effective alternatives for
municipal sewage treatment at sites where conditions are favorable for low
hydraulic loading combined with cropping practices.
This report contributes to the knowledge which is essential for the
U.S. Environmental Protection Agency to meet requirements of environmental
laws and enforce pollution control standards which are reasonable, cost
effective and provide adequate protection for the American public.
Clinton W. Hall, Director
Robert S. Kerr Environmental Research
Laboratory
111
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ABSTRACT
The Lubbock Land Treatment System consists of two privately owned
farms. The Gray farm comprises 1,489 ha and has been reusing treated
wastewater for crop irrigation for more than 40 years. In 1981 the land
application system was enlarged to include the Hancock farm which had 1,153
ha under cultivation. The primary irrigation mode employed by both farms
was spray irrigation using center pivot irrigation machines. The Lubbock
Land Treatment system Research and Demonstration Project involved the 1)
physical expansion of the Lubbock Land Treatment System; 2) characteriza-
tion of the chemical, biological and physical conditions of the ground
water, soils, -and crops prior to and during irrigation with secondary
treatment municipal wastewater; 3) evaluation of health effects of slow
rate land application of secondary effluent; and 4) assessment of the
effects of hydraulic, nutrient and salt mass loadings on crops, soil and
percolate.
During the period when a portion of the treated wastewater was divert-
ed to the Hancock farm, a decrease in the ground-water level beneath the
Gray farm was measured. In conjunction with the lowering of the ground-
water table was an increase in water quality beneath most of the farm (pri-
marily the ground water underlying the spray irrigated areas). The culti-
vation of' alfalfa in the spray irrigated areas was probably the primary
factor affecting the quantity and quality of percolate.
Chemical and nutrient constituents in the treated wastewater applied
to the Hancock farm were removed by the soil-crop matrix. An increase in
ground water beneath the Hancock farm resulted from deep percolation of
surface runoff collected in moats surrounding the reservoirs and excava-
tions constructed to reduce flooding of crop land. Deep percolation of
surface runoff leached existing nitrate and salt deposits within the soil
profile to the ground water; thereby, causing increased ground-water
nitrate and total dissolved solids concentrations.
The epidemiological study conducted on the populace in and surrounding
the Hancock farm indicated that wastewater spray irrigation produced no
IV
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obvious disease during the project period. However, the rate of viral
infections was slightly higher among participants who had a high degree of
aerosol exposure. The polio virus 1 infections during spring 1982 were
probably related to this.exposure.
Agricultural studies showed that cotton and grain sorghum produced
greater yields with increasing annual hydraulic loading rates up to
3m.ha/ha.yr. The highest alfalfa yields were obtained in test plots irri-
gated with 365 and 434 cm.ha/ha.yr. The alfalfa test plots appeared to
remove all nutrients applied in the wastewater stream. Salts were leached
beyond 91 cm of soil in all plots receiving 60 cm.ha/ha.yr or greater.
The Lubbock Land Treatment System Research and Demonstration Project
was conducted by Lubbock Christian College Institute of Water Research
(LCCIWR), Southwest Research Institute (SwRI), University of Illinois (UI)
University of Texas at San Antonio (UTSA), University of Texas at Austin
(UT), and Texas Tech University (TTU). This report was submitted in ful-
fillment of CR807501 and CS806204 by LCCIWR under primary sponsorship of
the U.S. Environmental Protection Agency. This report covers a summary of
research activities performed from May 1, 1980 through December 31, 1983.
This work was completed on June 30, 1985.
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CONTENTS
Foreword iii
Abstract iv
Figures viii
Tables ix
1. Introduction 1
Background 2
Description of Land Application System, Expansion 2
Effluent Quality 6
System Operation 13
2. Conclusions 19
3. Project Design -.25
Demonstration/Hydrogeologic Study 25
Lubbock Infection Surveillance Study 29
Percolate Investigation in the Root Zone 33
Agricultural Research Studies 37
4. Summary of Findings
Demonstration/Hydrogeologic Investigation . 41
Lubbock Infection Surveillance Study . 69
Agricultural Research Studies 81
References 88
Appendices
A. Agricultural Cropping Patterns 90
B. Supplemental Figures and Tables for Section 3 94
C. Supplemental Figures and Tables for Section 4 101
Preceding page blank
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LIST OF FIGURES
Number Name Page
1
2
3
4
5
6 '
7
8
9
10
11
Southeast Water Reclamation Plant Flow Diagram
Hancock Farm Hydraulic Distribution System
Precipitation During Project Period
Gray Farm Land Application Site
LISS Study Design: Time Frame of Monitoring in Relation to
Major Periods of Irrigation '. .
Plan of Test Facility .
Nitrate Concentration (mg/1) in Well Water under Gray Farm,
Baseline Period, 1981-1982 '
Illustration of Nitrite+Nitrate Lenses in Hancock Soil, 1981.
Inorganic Nitrogen in 183 cm Profile at the Hancock Farm. . .
Sampling Zones Comprising Study Area
Variation of Nitrate Concentration in Percolate and Accumu-
3
5
16
17
31
35
45
61
62
70
lated Weight of Leached Nitrate in kg/ha with Time for Tube
123 from July through December 1982' 79
12 Nitrogen Mass Balance for Trial 14000 Cotton Plots 83
13 Nitrogen Mass Balance for Trial 16000 Alfalfa Plots 85
14 Soybean Seed Yield vs Hydraulic Loading - Trial 17000 .... 86
15 Milo Whole Plant Yield vs Hydraulic Loading - Trial 17000 . . 86
vm
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LIST OF TABLES
Number Name Page
1 Characterization of Effluent Produced by Southeast Water
Reclamation Plant in 1980 and 1981 7
2 Concentration of Trace Elements in Treated Wastewater .... 9
3 Microorganism Concentrations in Wastewater Applied by
Sprinkler Irrigation 12
4 Bacterial Screen—Hancock Reservoir 12
5 Total Water Applied to Hancock Farm in 1983 15
6 Gray Farm Hydraulic Loadings/Crop 18
7 Type and Number of Underground Water Sampling Points by Site. 26
8 Treatment Matrix Hydraulic Loading Rate for Trial 17000 ... 39
9 Statistics of Depth to Water in Observation Wells at Gray
Site During Project 42
10 Percent of Gray Farm Well Water Samples Which Exceed or Equal
Drinking Water Standards for the Following Parameters .... 44
11 Trace Metals Mass Balance on Soils Collected from Flood
Irrigated Area 51
12 Statistics of Depth to Water in Observation Wells at Hancock
Site During Project 54
13 Percent of Hancock Farm Well Water Samples Which Exceed or
Equal Drinking Water Standards for the Following Parameters . 55
14 Metals Mass Balance for Hancock Farm 64
15 Cotton Yields, Hancock Farm 67
16 Elemental Shifts in Cotton Tissues Obtained from Hancock
Farm 1981 vs 1983 68
17 Comparisons of Shift.in Farmers' Income Pre-effluent to
Post-effluent 68
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SECTION 1
INTRODUCTION
Agriculture is the major user of freshwater in the United States with
approximately 99 percent of the agricultural water demand used for irriga-
tion (Williams, 1982). Increasing water demands by agriculture, industry
and municipalities have created severe water shortages in various regions
of the United States and the world. Application of municipal wastewater to
agricultural lands is a viable alternative to reduce the withdrawal of
freshwater from surface water and ground-water sources. In addition, land
application of wastewater is a cost-effective treatment alternative. Slow
rate wastewater application, usually in the form of spray irrigation, is
the most widely used form of land application.
The Lubbock Land Treatment System Research and Demonstration Program,
funded'by Congress in 1978 (H.R. 9375), was designed to address the various
issues concerning the use of slow rate land application of municipal waste-
water. The project involved the 1) physical expansion of the Lubbock Land
Treatment System; 2) characterization of the chemical, biological and phys-
ical conditions of the ground water, soils and crops prior to and during
irrigation with secondary treated municipal wastewater; 3) evaluation of
the health effects associated with the slow rate land application of secon-
dary effluent; and 4) assessment of the effects of hydraulic, nutrient and
salt mass loadings on crops, soil and percolate. Results from the Lubbock
Land Treatment Research and Demonstration Project are published in four
volumes:
1. Volume I: Demonstration/Hydrogeologic Study (George et al 1985);
2. Volume II: Percolate Investigation in the Root Zone (Ramsey and
Sweazy 1985);
3. Volume III: Agricultural Research Study (George et al 1985); and
4. Volume IV: Lubbock Infection Surveillance Study (LISS) (Camann
et al 1985).
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BACKGROUND
During the 1930s the City of Lubbock entered into a contractual agree-
ment with Dr. Fred Standefer to pump all the sewage effluent to his farm,
later to be known as the Gray farm. As Lubbock grew, the Gray farm was
able to expand to encompass 1,489 ha. Nonetheless, the Gray farm could not
adequately manage the hydraulic flow pumped from the City of Lubbock. Con-
sequently, the farm was over-irrigated and ground water accumulation oc-
curred beneath the farm with associated water quality problems.
In November 1980 construction commenced to expand the Lubbock Land
Treatment System to include the Hancock farm located 25 km southeast of
Lubbock. and directly north of the City of Wilson, Texas. The expansion was
designed to reduce the hydraulic and nutrient overloaded condition of the
Gray farm. The combined area of the Lubbock Land Treatment system was 2,967
ha (7,330 acres).
DESCRIPTION OF LAND APPLICATION SYSTEM EXPANSION
Lubbock1s Southeast Water Reclamation Plant (SeWRP) consists of two
trickling filter systems and an activated sludge system (Figure 1). Un-
chlorinated effluent from the two trickling filter plants.was pumped to the
Gray and Hancock farms.
A total wastewater discharge of approximately 5.5 x 10\i-Vd (15 mgd)
was to be divided equally between the Gray and Hancock land application
sites. Effluent from SeWRP was conveyed to the Hancock land from a three-
pump, pumping station through 25 km of 0.69 m force main.
The diurnal flow variation within the wastewater treatment system due
to the management of water between the trickling filter plants and the
activated sludge plant reduced flow through the trickling filters from 2:00
a.m. to 10:00 a.m. each day to 315 nvVhr (2.0 mgd). The pump capacity and
sump were not designed to absorb the variations in flow from the trickling
filter plant. Consequently, the dynamic nature of the effluent hydrograph
made it impossible to operate two pumps for more than 16 hours each day.
At the northern boundary of the Hancock farm, the effluent was routed
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Lime
Aeration
Treatment
Supernatant
Primary
Clarifiers
Trickling Secondary
Filters Clarifiers
X L_l
, , Anaerobic, Digesters
-*- Digested Sludge
Trickling
Filters
Hancock Hancock
Lagoons Farm
Secondary
Clarifiers
Screens Grit
Chamber
Return Sludge
Plant Generator
fteTurnSTudae'
Secondary
' Clarifiers
Chlorine
Contact Chamber I
I t SjJa^r^keILer_D^s^s^LO^tpige.sted Sludge
Power
Utility
Figure 1. Southeast Water Reclamation Plant Flow Diagram
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through three 0.38 m plastic irrigation pipelines to three separate reser-
voirs (Figure 2). The reservoirs were constructed on natural playa lakes.
The reservoir capacity was adequate to provide emergency storage during
rainfall events, and to prevent the necessity of irrigating during periods
of cultivation, seeding, and harvesting of crops. Approximately 3.5 months
of storage were provided by the three reservoirs. Irrigation pump sta-
tions were provided at each reservoir. Constant pressures were maintained
throughout the system by a variable speed (lead) pump and a-constant speed
(lag) pump located on Reservoir 1. Both pumps were controlled by system
pressure and discharge flow rate.
The hydraulic distribution system was designed to irrigate 1,153 ha
with 1,082 ha irrigated by electric drive center pivot irrigation machines.
Each center pivot was designed tg irrigate up to 15 cm in 20 days after
allowing for 20 percent loss due to evaporation. Without the use of the
reservoirs, five to six center pivots could be operated at the same time,
utilizing the flow pumped directly from Lubbock1s wastewater treatment
plant. Each center pivot had a centrifugal booster pump. The booster pumps
increased the line pressures to an operating level of 3.1 x 10° pascals (45
psi).
In-line screens were placed between the centrifuge booster pumps and
the center pivots to reduce clogging of the spray nozzles. On each irriga-
tion machine Nelson® spray nozzles were installed on drops located 3.2 m
apart. The size of the nozzles varied from 2.4 mm (3/32 in) to 7.1 mm
(9/32 in). Nozzles were positioned a distance of 1.2 m to 1.8 m above the
ground which allowed easy maintenance of the nozzles. Each nozzle provided
a 360° umbrella pattern with an effective wetted diameter of 8.5 to 9.1 m
(28 to 30 ft) to allow for the greatest application intensity. The energy
dissipating deflector incorporated into the nozzle assembly was a concave
plastic plate. Water discharged through the orifice was deflected upward
once it struck the deflector which enhanced the creation of aerosols during
the period of study and increased drift and evaporation of water. Convex
deflectors were installed on most nozzles after the LISS monitoring period
ended (i.e., after October 1983) to direct the water downward. This change
reduced aerosol formation and drift. In addition, end guns were provided
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Fore* Main
from S.WHP
Furrow Irrigation
Distribution Can
Figure 2. Hancock Farm Hydraulic Distribution System
5
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on each pivot to irrigate the corners.
EFFLUENT QUALITY
During 1980 and 1981, Lubbock's SeWRP was producing an effluent from
the trickling filter system which had a composition equivalent to a typical
medium untreated domestic wastewater (Table 1). The City of Lubbock's
wastewater discharge permit for SeWRP required the plant to produce an
effluent with a 30-day-average 5-day biochemnical oxygen demand (8605) not
greater than 45 mg/1. During the project monitoring period the effluent
BODj quality from SeWRP ranged from a monthly high of 260 mg/1 to a monthly
low of 27 mg/1:
Average Monthly Effluent 8005
_ Produced by Lubbock SeWRP
Month
January
February
March
April
May
June
July
August
September
October
November
December
This poor quality effluent was mainly attributable to the malfunctioning of
the anaerobic digestion process. From June 1980 to February 1982, the aver-
age effluent total organic carbon (TOC) produced from trickling filter
Plant 2 was 118.7 mg/1. Total Kjeldahl Nitrogen (TKN) concentration aver-
aged 38.59 mg-N/1 of which 67 percent was ammonia-nitrogen (25.95 mg N/l)
and 33 percent was organic nitrogen. Approximately 57 percent of the total
1982
mg/1
• 143
260
198
139
108
128
130
76
69
171
63
86
1983
mg/1
71
120
105.
65
30
39
49
27
43
31
63
49
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TABLE 1 . CHARACTERIZATION OF EFFLUENT PRODUCED BY
SOUTHEAST WATER RECLAMATION PLANT IN 1980 AND 1981
Parameter
Alkalinity (mg CaCOyl)
Specific Conductance (pmhos/cm)
Total Dissolved Solids (mg/1)
pH
Chloride Ion (mg/1)
Sulfate Ion (mg/1)
Total Kjeldahl Nitrogen (mg N/l)
Nitrite plus Nitrate Nitrogen (mg N/l)
Ammonia .Nitrogen (mg N/l)
Total Phosphorus (mg P/l)
Orthophosphate Phosphorus (mg P/l)
Organic Phosphorus (mg P/l)
Chemical Oxygen Demand (mg/1)
Total .Organic Carbon (mg/1)
Concentration
Average
337
2216
1695
7.54
468
315
38.59
0.29
25.95
14.43
8.36
5.15
302
118
Standard
Deviation
34
290
537
0.21
55
43
.15.23
0.30
6.69
.4.27
2.03
4.20
136
45
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phosphorus (14.43 mg/1) present in the effluent from the trickling filter
plant was orthophosphate phosphorus (PO^). During the spring of 1982,
SeWRP placed on-line additional anaerobic digesters and rehabilitated the
primary clarifiers and rotary distributors of the trickling filter plants.
A much higher quality waste stream was pumped to the Hancock and Gray farms
in 1982 through 1983. TOC levels at the terminus of the forced main were 46
percent less than the average concentrations measured in trickling filter
plant effluent samples obtained the previous sampling periods. No statis-
tically significant differences ( a = 0.05) were observed in TKN levels
measured in the waste streams from Plant #2 (38.59 mg N/l) and at the term-
inus of the force main (41.70 mg N/l). As SeWRP1s effluent reached the
Hancock farm, 62 percent of the TKN was ammonia-nitrogen (25.80 mg N/l).
The data indicate no nitrogen transformations through the force main.
Average total phosphorus (TP) and organic phosphorus (Org P) levels (11.82
mg/1 and 1.6 mg/1) contained in water samples obtained from the terminus of
the force main did decrease significantly from baseline effluent concentra-
tions. The decrease in TP appeared to be a result of a decrease in organic
phosphorus mass loading from the trickling filter plant. As anticipated,
the bulk (71 percent) of the nitrogen contained in the water entering the
Hancock farm (41.77 mg-N/1) was lost within the reservoirs. The reservoir
effluent average TKN concentration was 11.74 mg-N/1. The median nitrite
plus nitrate (N02+N03 level in the reservoir discharge stream was 0.27 mg
N/l. . .
Approximately 85 percent of the total phosphorus contained in the
effluent (11.82 mg/1) pumped to the Hancock farm was orthophosphate. Aver-
age orthophosphate levels decreased from 8.43 to 4.85 mg/1 and as the
wastewater flowed through the reservoirs total phosphorus concentrations
were reduced by 47 percent from 11.82 mg/1 to 6.31 mg/1. Orthophosphate
removal in the reservoir accounted for about 65 percent of the decrease in
TP.
The wastewater effluent pumped to the Gray farm was significantly
affected by the activated sludge plant. The nitrate-nitrogen concentration
averaged 3.45 mg/1. Furthermore, the higher treatment efficiency of the
activated sludge plant decreased the TOC levels to an average of 52.6 mg/1.
8
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Uptake of phosphorus by suspended biomass, also, significantly reduced the
average TP concentration (9.18 mg/1) in the waste stream pumped to the Gray
farm.
The sewage treated by SeWRP was primarily derived.from domestic
sources with less than 30 percent contributed from industrial sources.
Trace metal levels contained in SeWRP effluent reflected this low indus-
trial wastewater flow and presented no potential phytotoxicity problems.
Table 2 summarizes the concentration ranges of specific trace metals meas-
ured in treated wastewaters. No significant differences ( a= 0.05) In
trace metal and mineral levels were determined between any irrigation
water source from February 1982 to October 1983.
TABLE 2. CONCENTRATION OF TRACE ELEMENTS IN TREATED WASTEWATER
Element
As
B
Cd
Cr
Cu
Hg
Mo
Ni
Pb
Se
Zn
Wastewater Ef
Range*
(mg/1)
<0. 005-0. 023
0.3-2.5
<0. 005-0. 22
<0. 001 -0.1
0.006-0.053
<0. 0002-0. 001
0.001-0.018
0.003-0.60
0.003-0.35
0.004-.35
fluent Median Concentration (mg/1)
Median*
(mg/1)
<0.005
0.7
<0.005
0.001
0.018
0.0002
0.007
0.004
0.008
0.04
SeWRP
<0.005
0.027
<0.0005
0.060
0.047
<0.0004
<0.003
0.065
0.032
<0.005
0.133
Hancock
Reservoir
<0.005
0.038
. <0.0005
0.006
0.033
<0.0004
<0.003
0.007
<0.005
<0.005
0.066 "
* Chang and Page, Land Treatment of Wastewater, Vol. 1, pp.47
The data indicate that minerals may create salinity and sodic prob-
lems within the upper soil profile. The effluent produced by SeWRP was
slightly saline (dissolved solids from 1,000 to 3,000 mg/1). The low hy-
-------
draulic loading to the Gray and Hancock, farm (20 to 60 cm) could contribute
to the accumulation of salts within the upper soil profile. Without proper
salt management, salts could pose future phytotoxicity problems to farmers.
The adjusted sodium adsorption ratio (SAR) of the effluent stream from the
trickling plant averaged 21.6. Irrigation water with an adjusted SAR above
10 may create severe water penetration problems and development of alkali
soils (Stromberg and Tisdale 1979, EPA 1981, Loehr et al 1979). Proper
management of salts contained in the irrigation water was viewed as the
most important task which would govern the long term success of 'the land
application system.
Since agriculture is the major industry in the Lubbock area, herbi-
cides (e.g., atrazine and propazine) and by-products produced from the
decomposition of herbicides (e.g., 2,3-dichloroaniline and 3,4-dichloro-
aniline) existed in the SeWRP's effluent. Carbon tetrachloride, chloroben-
zene, and diethylphthalate .levels exceeded the respective organic concen-
tration range in municipal wastewater treatment plants cited by Majeti and
Clark (1981) and Pettygrove and Asano (.1984). A mean anthracene concentra-
tion of 6.1 ug/1, 4.0 yg/1 and 8,4 yg/1 was contained in the effluent from
the trickling filter plant; wastewater pumped to the Gray farm; and efflu-
ent at the terminus of the force main, respectively.
The average fecal coliform concentration in the waste stream pumped to
the center pivot irrigation machine exceeded EPA guidelines throughout the
study period. The guidelines state:
"Biological treatment by ponds or inplarit processes plus con-
trol of fecal coliform count to less than 1,000 MPN/100 ml -
acceptable for controlled agricultural irrgation except for
human food crops to be eaten raw." (USEPA, 1981)
The actual flow-weighted average fecal coliform concentrations of the
applied wastewater during the four major irrigation periods were:
10
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Fecal coliform concentration
colony forming units (cfu)/100 ml
Spring 1982 4,300,000
Summer 1982 840,000
Spring 1983 ' 5,200
Summer 1983 120,000
During the first two years of the study (June 1980 to February 1982),
total enterovirus levels as measured on HeLa cell monolayers ranged from
0.045 pfu/ml to over 1.0 plaque forming unit (pfu/ml) in the summer of
1980. The first effluent sample from the terminus of the force main was
obtained at the Hancock farm in February 1982 and represented a highly
atypical microbiological sample. Once a daily wastewater flow to the
Hancock site was established, the initial microbial and physical profile of
the wastewater delivered to the irrigation site was not dissimilar from the
wastewater previously characterized at the treatment plant. In 24-hour
composite samples, maximal viral levels of about 0.1 pfu/ml were detected
during the summer 1982 irrigation season. A similar pattern of enteric
viruses enumerated on HeLa cell monolayers was observed during 1983. While
viral levels in effluent at the pipeline terminus did not reach the highest
levels seen in June 1982, the number of viruses recovered remained rela-
tively constant from late June through August 1983 at over 0.25 pfu/ml.
A comparison of both indicator bacteria and virus levels showed that,
in general, organism concentrations in reservoir water were two to three
orders of magnitude lower than comparable wastewater at pipeline terminus
(Table 3). Of the 19 samples of reservoir water concentrate which were
assayed in two cell lines, enteroviruses were detected in only 12 samples
with a maximum level of about 0.06 pfu/ml. In most of the reservoir sam-
ples, viral levels were at or below the detection sensitivity of the recov-
ery procedures employed.
The most prevalent Enterobacteriaceae species encountered in waste-
water from Lubbock included Citrobacter, Enterobacter, Escherichia and
Klebsiella. Aeromonas hydrophila was the most abundant non-Enterobacteria-
ceae member recovered, followed by Pseudomonas species. The effectiveness
11
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TABLE 3. MICROORGANISM CONCENTRATIONS IN WASTEWATER APPLIED BY SPRINKLER
IRRIGATION
Measurement by
irrigation period
Wastewater Source
Pipeline
effluent
a
Reservoir
effluent0
FECAL COLIFORMS (colony forming units/ml)
Feb-Apr 1982
Jul-Sep 1982
Feb-Apr 1983
Jul-Sep 1983
ENTEROVIRUSES (plaque forming units/ml)
43,000
13,000
20,000
90,000
130
50
30
. Feb-Apr 1982
Jul-Sep 1982
. Feb-Apr 1983
Jul-Sep 1983
0.04
0.05
0.07 .
0.17
0.003
<0.004
<0.004
Geometric mean
Geometric mean
of four to eight 24-hour composite samples.
of four to five grab samples.
TABLE 4. BACTERIAL SCREEN-- HANCOCK RESERVOIR
Organisms (10 cfu/ml)
Sampling date
Jul 26-27,
1982
ENTEROBACTERIACEAE
Enterobacter cloacae
Klebsiella oxytoca
Klebsiella ozaenae
NON-ENTEROBACTERIACEA
Achromabacter xylosoxidans
Acinetobacter calcoaceticus var. Lwoffi
Aeromonas hydrophila
Alcaligenes sp.
CDC Group V E-2
Pseudomonas sp.
Psuedomonas cepacia
Pseudomonas maltophilia
0.4
0.1
0.1
0.9
0.2
4.3
0.5
0.1
0.5
0.1
0.3
a. Highest levels observed on either MacConkey agar of brilliant green agar
and identified by API 20E bio-chemical tests.
12
-------
of ponding for the reduction of microbial numbers was evident both by the
lower levels and the reduced diversity of organisms seen in a single bac-
terial screen completed on a sample from the Hancock reservoir (Table 4).
Since microorganism densities were much higher in the wastewater from the
pipeline than from the reservoirs, the exposure which most of the study
population received to most microorganisms via the wastewater aerosol was
greater in 1982 than in 1983.
During system operation, the fecal coliform concentration of the waste
stream from SeWRP and the discharge from the storage reservoirs greatly
exceeded EPA guidelines, especially in 1982. The effluent 8005 concentr-
ation produced by SeWRP did not satisfy Texas permit, requirements until May
1983. The system, however, was operated below hydraulic design capacity in
1982 and 1983.
SYSTEM OPERATION
Hancock Farm
The Hancock slow rate system had the following alternative operational
modes:
^
1. Direct irrigation with effluent from SeWRP;
2. Irrigation with water only from reservoir; and
3. Combined direct irrigation with SeWRP effluent and reservoir
water.
During 1982 the Hancock farm was irrigated primarily with secondary
effluent produced by SeWRP. Odorous compounds stripped from the effluent
stream as it was emitted from the spray nozzles created public nuisance
conditions. Consequently, the reservoirs were used to oxidize the odor
compounds prior to irrigation. In 1983 practically all of the water ap-
plied to land was pumped from the storage reservoirs. Since the same pipe-
line distribution network was used to provide water to the center pivot
irrigation machines and transport Water to the reservoirs, main pipelines
had to be dedicated to either irrigation from the reservoirs or transport-
ing water to the reservoirs. Increased head losses resulting from closing
of valves to accomplish irrigation solely from the reservoirs, in conjunc-
13
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tion with the wastewater management condition at SeWRP, reduced the flow
pumped to the Hancock farm. Consequently, the Hancock farm received only 28
percent (4,128,219 m3) of the total effluent produced from February through
December 1982. In 1983, 19 percent (3,744,395 m3) of the total effluent
was pumped to the Hancock farm from January 1 through October. The
hydraulic loading pumped through each center pivot irrigation machine in
1982 and 1983 is presented in Table 5. These hydraulic loadings are very
low for a slow rate land application system.
Due to the necessity to divert all SeWRP effluent to the reservoirs,
water management at the farm was a problem. A maximum of nine of 22 center
pivot machines were operated simultaneously. Consequently, system hydraul-
ics was the major factor which governed irrigation practices and not crop
requirements. Cotton was the primary crop grown at the Hancock farm prior
to 1982. Rainfall and associated hail during the months of May and June
1982 which were the 24th and 25th months of the study monitoring period
(Figure 3) destroyed over 8.09 x 10^ ha (2 x 10^ acres) of the cotton crop
in the South Plains of Texas. Only 16.2 ha (40 ac) of cotton remained on
the Hancock farm. The majority of the farmers planted grains to partially
recuperate financial losses. Tenant farmers at the Hancock farm planted
approximately 552 ha (1365 ac) of grain sorghum, 162 ha (400 ac) of sun-
flowers, and 257 ha (635 ac) of soybeans (Figure A.1).
During the summer of 1983, less than 2.5 cm (1 inch) of rain was
recorded from the end of 3une through mid-October. Figure A.2 shows the
crops grown in 1983 at the Hancock farm.
Gray Farm
Secondary treated effluent from SeWRP was delivered to the Gray farm
through three pipelines to three storage reservoirs (Figure 4). The esti-
mated hydraulic retention time of the ponds was 10 days.
Prior to 1982, with 75 to 80 percent of the farm planted in cotton,
water was applied to the cotton areas in early spring, February through
April (prewater); and in the summer from June through August. An estimated
70 cm of water was applied to the land designated for cotton planting
(Table 6). Any other irrigation (the remaining six months), with no stor-
14
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TABLE 5. TOTAL WATER APPLIED TO HANCOCK FARM IN 1983
Pivot No.
1
2
3
4
5
6
7
. 8
9
10
11
12 •
13
14
15
16
17
18
19
20
21
22
Total
(cm)
13.23
20.50
18.16
23.16
11.79
20.47
19.69
14.58
14.38
13.13
23.80
20.50
16.26
10.72
26.06
14.68
17.15
18.49
15.72
15.52
16.94
14.78
1982
(in)
5.21
8.07
7.15
9.12
4.64
8.06
7.75
5.74
5.66
5.17
9.37
8.07
6.40
4.22
10.26
5.78
6.75
7v28
6.19
6.11
6.67
5.82
Total
(cm)
20.0
34.0
. 27.0
48.0
40.9
50.0
31.8
26.9
38.4
29.0
29.2
31.0
33.3
22.9
43.9
35.3
29.2
29.0
30.2
17.5
20.6
27.4
1983
(in)
7.9
13.4
10.6
18.9
16.1
19.7
12.5
10.6
15.1
11.4
11.5
12.2
13.1
9.0
17.3
13.9
11.5
11.4
11.9
6.9
8.1
.10.8
15
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o
o
C\J
D Lubbock Airport
O Normal Precipitation
A Hancock Farm
-j~ Gray Farm
1.00
6.00
11.00 16.00 21.00 26.00
MONTHS (JUNE 1980-SEPT 1983)
31.00
36.00
m.oo
Figure 3. Precipitation During Project Period
-------
••••- Pipeline
Water
1 cm = 0.27 km
SPRINGS
Figure 4. Gray Farm Land Application Site
-------
age, had to be put on winter crop or grazing area (Figure A.3). From two
to 4.5 m/yr was applied to these areas in order to keep the main economic
crop (cotton) at maximum production. In the spring of 1982 over 506 ha
(1,250 ac) of alfalfa (Figure A.4) , 304 ha (750 ac) of wheat, and 121 ha
(300 ac) of soy beans were planted on the Gray farm.
TABLE 6. GRAY FARM HYDRAULIC LOADINGS/CROP*
Season
Prior to
1982
1982
1983
Flow
MGD
14
10
10
Cotton Milo Wheat
121 1
70 cm 65 cm — 465 cm
70 cm 230 cm
70 cm 207 cm
Soybeans Alfalfa
1 1 2
—
70 cm 70 cm 55 cm
70 cm 55 cm
* Approximate loadings applied based on maximum output pivot and number
of days of potential operation during the growing season.
1 Row or flood irrigation areas. Row water crops are based on one pre-
water application and six summer time applications.
2 Center pivot irrigation — Pivots are nozzled to deliver 15 cm/21 days,
over six months application time (7 on alfalfa). This yields hydraulic
loadings of 90 cm (105 cm on alfalfa). Because only enough pivots are
on hand to irrigate one-half of the acreage at any one time, these load-
ings must be halfed to 45 cm/yr and 52 cm/yr, respectively.
18
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SECTION 2
SUMMARY OF CONCLUSIONS
The Lubbock Land Treatment System consists of two privately owned
farms. -In the past years, the Gray farm suffered from inadequate storage
and distribution piping network to properly manage effluent produced by
Lubbock1s SeWRP. Consequently, an increase in ground-water elevation and
degradation of ground-water quality occurred beneath the farm. The system
was expanded in 1981 to include the t,478 ha Hancock farm which is located
25 km southeast of Lubbock, Texas. The expanded slow rate land application
system encompassed approximately 2,967 ha. From June 1980 to October 1983,
both farms were monitored to assess the impacts on ground water, soils and
crops of: 1) reducing the hydraulic, chemical, and biological mass loading
for the Gray farm; and 2) spray irrigation of effluent to the Hancock farm
which was primarily a dry land farm for ten years prior to 1982. Further-
more, an epidemiologic study at the Hancock farm was conducted to assess
the association between human exposure to the wastewater used for irriga-
tion and the development of new infections.
The findings of the project indicated that the major recharge of
ground water beneath the Gray farm was from flood irrigated wheat areas.
Deep percolation of irrigation water and precipitation continued in 1982
and 1983 in the flood irrigated areas. Physical limits of irrigation
equipment, hydraulic distribution system, water storage, and crop cultiva-
tion eliminated the capabilities for proper water management. With ade-
quate winter storage and the hydraulic capability to distribute more water
on the alfalfa in 1982 and 1983, minimal deep percolation would have
occurred through the soil throughout the farm. Comparison of 1981 and 1983
ground-water elevation data indicated that the ground-water levels beneath
the Gray farm decreased.
During the period from February 1982 to October 1983, an increase in
the ground-water quality also occurred beneath most of the Gray farm. Mass
balances conducted on nutrient and minerals indicated continued leaching of
19
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constituents through a soil depth of 183 cm beneath the flood irrigated
area; whereas, most of the chemical constituents applied by sprinkler irri-
gation were retained and/or removed through crop uptake beneath the spray
irrigated areas.
Statistically significant decrease in NQ.3-N levels were measured in
five of 27 monitoring wells from February 1982 to October 1983. In gen-
eral, 17 of 27 wells experienced a decrease in ground-water NOj-N levels. A
comparison of baseline data (June 1980 to February 1982) and data collected
after February 1982 indicated a decrease in the frequency of ground-water
NOj-N concentrations equaling or exceeding drinking water standards in nine
of 27 wells monitored.
Wastewater treated by SeWRP was primarily derived from domestic
sources with less than 30 percent contributed by industrial sources. Con-
sequently, trace metals posed no potential toxicity problems to humans or
plants.
Total irrigation at the Hancock farm varied from 16 cm to 20 cm in
1982 and 36 to 49 cm in 1983. An overall increase in ground-water eleva-
tion occurred beneath the Hancock farm. A maximum rise of three to five
meters was experienced in ground-water wells in close proximity to surface
runoff collection areas. Increases in ground-water elevation beneath the
Hancock farm were primarily due to percolation of surface runoff through
coarse material contained in moats surrounding the reservoirs and excava-
tions constructed to reduce flooding of cropland and migration of percolate
through material surrounding poorly sealed well casings. Increases in
ground-water elevation commenced approximately two months after heavy pre-
cipitation events.
Chemical constituents contained in the treated wastewater applied to
the Hancock farm were removed by the soil-crop matrix from percolate water.
Increases in ground-water chemical parameters appeared to be associated
with deep percolation of surface runoff contained in moats and excavation
pits constructed to contain surface runoff. Existing salt and nitrate
deposits within the soil profile were leached with percolate to the ground
water; thereby causing increases in nitrate and total dissolved solids
(IDS) levels in several wells.
20
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In general, no significant changes in trace metals or priority organic
pollutants occurred in the ground water during the monitoring period. Based
on values cited in literature, trace elements posed no public health prob-
lems.
Salt accumulation occurred in the upper 183 cm of the soil profile.
As expected, salt accumulations were directly proportional to mass loadings
from irrigation. Insufficient water was applied (less than 21 cm in 1982
and less than 50 cm in 1983) to leach salts below the root zone. Exchange-
able sodium percentage increased from two to six percent in the top 30 cm
of soil during the period from February 1982 to.October 1983.
Cotton and grain sorghum (milo) were the primary crops grown on the
Hancock farm in 1980, 1981 and 1983. Due to severe weather in 1982, sun-
flowers, soybeans and grain sorghum were planted as alternative crops to
cotton. While milo yields were low due to late planting and trifluralin
damage, sunflower and soybean yields were average for the High Plains area
of Texas. An improvement in cotton crop production occurred in 1983. With
irrigation with effluent, the cotton yields for the farm were 48 percent
greater than the Lubbock County average. 1983 cotton yields may have been
limited by possible nutrient shortages, boll worm infestation, and. cool
weather during late growing season. Cotton production in 1983 ranged from
353 to 740 kg/ha.
Amortized system construction cost over a 20 year period at ten per-
cent annual interest rate would be.$167/1 ,000 m3 per year ($0.63/1,000
gal). With 85 percent federal cost sharing amortized construction cost
would have been reduced to $25/1,000 m3/yr ($0.10/1,000 gal). Inclusion of
land cost would have increased annual capital cost by 24 percent. Total
operation and maintenance (0 & M) costs associated with the Lubbock Land
Treatment System Expansion were $156/1,000 m3 ($0.59/1,000 gal) in 1982 and
$139/1,000 m3 ($0.53/1,000 gal) in 1983. The City of Lubbock bore
$71/1,000 m3 of the total 0 & M cost in 1982 and $58/1,000 m3 in 1983. The
farmer's portion of the 0 & M was $85/1,000 m3 ($0.32/1,000 gal) and
$81/1,000 m3 ($0.31/1,000 gal) in 1982 and 1983, respectively. The economic
balance of cost expended and revenues received showed a net negative bal-
ance each year during the project period (1980 through 1983) ranging from
21
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$701,661.81 (1981) to $1,103,687.57 (1982). Net costs were $267.35/1,000
m3 ($1.00/1,000 gal) in 1982 and $161.28/1,000 m3 ($0.61/1,000 gal) in
1983. Crop revenues offset costs by 18 and 47 percent of total costs in
1982 and 1983, respectively.
Spray irrigation of unchlorinated wastewater piped from the treatment
plant was a more substantial source of aerosolized microorganisms than
spray irrigation of wastewater stored in reservoirs. Enteroviruses were
regularly recovered in the aerosol at 44 to 60 m downwind of irrigation
with piped treatment plant wastewater. The geometric mean enterovirus
density in the downwind air was 0.05 pfu/nr, although a much higher density
(17 pfu/m3) was sampled in August 1982. In addition, fecal streptococci
levels were detected at least 300 m downwind, and levels of fecal coli-
forms, mycobacteria and coliphage were isolated at least 200 m downwind.
Organism levels downwind were also significantly higher than background
levels in ambient air outside of participants' homes: fecal coliform
levels were higher beyond 400 m downwind, mycobacteria and coliphage levels
to at least 300 m and fecal streptococci levels to at least 200 m.
The results indicate that a general association between exposure to
irrigation wastewater and new infections existed, especially for 1982 when
there was exposure to higher levels of micro-organisms via wastewater
aerosol. Poliovirus 1 seroconversions were probably related to wastewater
aerosol exposure during the spring of 1982, even when the effects of polio
immunizations were controlled. However, even during 1982, the strength of
association remained weak and frequently was not stable. Wastewater of
poor quality from the pipeline, comprised much of the irrigation water in
1982. Of the many infection episodes observed in the study population, few
appear to have been associated with wastewater aerosol exposure, and none
resulted in serious illness.
The lack of a strong, stable association of clinical illness episodes
with the level of exposure to irrigation•wastewater indicates that waste-
water spray irrigation produced no obvious disease during the study period.
However, when more sensitive indicators of infection were used, the evi-
dence indicates an association existed, especially for 1982. A particular
concern from a public health standpoint is the evidence that the poliovirus
22
-------
1 seroconversions were related to wastewater aerosol exposure during the
spring of 1982, even when the effects of polio immunizations were con-
trolled. Because of the low prevalence of poliovirus antibody observed
during the baseline period, the study population was immunized, and thus
was probably better protected against polio than other rural populations.
High concentrations of both bacteria and enteric viruses were observed in
the 1982 poor quality wastewater applied as received via pipeline directly
from the Lubbock sewage treatment plant. Exposure would have been reduced
by using wastewater from the reservoirs for irrigation rather than irrigat-
ing directly from the pipeline.
Annual hydraulic loading rates up 3 m.ha/ha.yr did not adversely
affect cotton, grain sorghum, and alfalfa crop production. Highest alfalfa
yields were obtained in test plots irrigated with 365 and 434 cm.ha/ha.yr.
Total dissolved solids and associated sodium salts were leached beyond 91
cm soil depth within plots irrigated with 61 cm of treated sewage per year
or greater. Bermuda yields were limited by transport of macro and micro
nutrients past the root zone.
Soybeans with a relatively shallow root system, produced highest
yields with more frequent irrigation (i.e., one irrigation per week).
Soybeans were unable to develop a deep root system to utilize deeper soil
moisture during periods of water stress (one irrigation every four weeks or
one irrigation every eight weeks); consequently, crop yields were reduced.
During long periods between irrigation events, the deep root system
developed by grain sorghum enabled the plant to utilize available soil
moisture and inorganic nitrogen at greater depths. Highest grain sorghum
production was achieved in plots irrigated 61 and 122 cm/yr at application
frequencies of once every four weeks and once every eight weeks.
Increasing the quantity of water applied to a crop transports sodium
salts deeper into the soil profile. Soybean seed and stalk analysis indi-
cated leaching of sodium from the root zone commenced almost immediately at
the 122 cm/yr hydraulic loading. At the 61 cm/yr loading, irrigation
events must occur at intervals of two weeks or longer to promote leaching
of sodium. Practically no leaching occurred even at the one application
per eight weeks frequency at the effluent loading of 31 cm/yr. With the
23
-------
shorter growing season experienced in 1982, soybeans may have had a higher
water consumption rate than the grain sorghum due to the crop's maturity.
Higher water requirement of soybeans in conjunction with its shallow root
system may have caused higher sodium accumulations in the upper 61 cm than
observed in grain sorghum test plots.
24
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SECTION 3
PROJECT DESIGN
The human and environmental monitoring portions of the Lubbock Land
Treatment Research and Demonstration Project was divided into two periods,
each monitoring period having a time span of approximately two years. T-he
baseline monitoring period extended from June 1980 to February 1982. Dur-
ing this time frame no effluent from SeWRP was pumped to the Hancock farm.
In February 1982 treated sewage from the City of Lubbock1s wastewater
treatment facility was pumped to the Hancock farm. The second phase of the
project monitoring period encompassed the land application of wastewater at
the Hancock farm which began in February 1982 and continued through Decem-
ber 1983. The design of each project investigation is presented in the
following text.
DEMONSTRATION/HYDROGEOLOGIC STUDY
The objective of the environmental monitoring program of the Demon-
stration/Hydrogeologic Study was to establish a data base characterizing
conditions at the Gray and Hancock farms that would allow the detection of
any changes which might occur in the ground water, soils, and crops due to
reduction of sewage effluent loading at the Gray farm, and use of sewage
effluent at the Hancock farm.
Ground water beneath the Gray and Hancock farms was monitored each
year after spring pre-irrigation (April), at the end of summer irrigation
(September) and in winter (December). Ground water samples were taken from
newly constructed monitoring wells, pre-existing irrigation wells, seeps
and springs at the Gray farms, and drinking water wells of residents on or
near the Hancock farm. Table 7 gives the number and types of ground-water
monitoring wells at each site. Sampling locations were selected using
hydrogeologic data in order to best monitor the movement and quality of
water on the farms. Figures B.1 and B.2 show the ground-water monitoring
location for each site.
25
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TABLE 7. TYPE AND NUMBER OF UNDERGROUND WATER SAMPLING POINTS BY SITE
Number of
Wells
1
5
3
15
23
1
5
11
10
1
11
Type of Well
HANCOCK FARM
Organic Non-contaminated well .30 cm (8 in)
Continuous water level recording wells 20 cm (12 in)
Non-continuous recording observation wells 10 cm (4
Pre-existing irrigation wells (currently in use)
Home drinking water wells
GRAY FARM
Organic non-contaminated well 20 cm (8 in)
Continuous water level recording wells 20 cm (8 in)
Non-continuous -recording observation wells 10 cm (4
Pre-existing irrigation wells (currently in use)
Multiple depth well [includes four, 12.5 cm (5 in)
Seeps, springs and retention pond overflows
in)
in)
wells]
During each sampling period depth to water measurements were made just
prior to taking water samples. Wells without pumps were sampled using a
7.6 cm (3 in) diameter, 122 cm (4 ft) long polyvinylchloride (PVC) bailer
with a neoprene check valve connected to a 0.6 cm (1/4-in) diameter cotton
rope. The bailer was cleaned between use in each well by immersion in
ethanol followed by a distilled water rinse. The bailer removed approxi-
mately 4 1 (1 gal) of water each time it was withdrawn from the well. Five
to 15 bails of water, depending on depth of water in the well's saturated
zone, were wasted before samples were obtained. The waste volume .was ap-
proximately 60 to 80 percent of the water in the well.
Twenty-four hour composite water samples were obtained from 1) the
Hancock and Gray effluent pump stations at the SeWRP; 2) the flow distri-
bution can at the terminus of the force main prior to the Hancock water
26
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distribution system; and 3) flow distribution cans which divided the efflu-
ent from the reservoirs to various locations on the farm.
Water samples from the Lubbock Land Treatment System Research and
Demonstration Project were analyzed for physical parameters, priority
organic pollutants, other organics, metals, other inorganics, and indicator
bacteria. During the project monitoring period, water samples were analyzed
for 104 parameters listed in Table 8.1.
Soil Samples
Soil sampling locations in the demonstration area were determined by
first dividing each farm into 65 ha areas (one quarter-section). On the
Hancock farm, each pivot encompassed approximately 65 ha (one quarter-
section). Each field on the Gray farm was approximately 65 ha (one quarter-
section) . Sampling locations were randomly selected within the 65 ha area.
Soil cores were pulled from each location and composited at 0.3 m (1 ft)
increments to make one sample for each depth. Soil samples were cored just
after harvest for cotton (November) and twice a year for double cropped
areas (April and November).
During the first sampling period (March 1981) and final sampling per-
iod (November 1983), 1 .8 m cores were obtained using a 10.2 cm diameter,
1.2m long coring tube. Cores were taken to only 0.91 m depth during the
intermediate sampling periods.
Soil samples were analyzed for the parameters shown in Table B.2. Soil
samples from the baseline years and final sampling period (winter of 1983)
were analyzed for the complete list of parameters. The 1982 soil samples
had only the top three, 30 cm sections analyzed for pH, conductivity,
potassium, total Kjeldahl nitrogen, total phosphorus and priority organ-
ics.
Crop Sampling
The purpose of crop sampling was to obtain plant samples which repre-
sented each farm, crop and type of irrigation. Sampling locations for crop
samples were determined in a manner similar to that for soil samples. The
two farms were divided into approximately 65 ha (quarter-sections) sampling
27
-------
areas, from which crop samples were randomly collected. Crop samples were
collected at harvest time when the crops had developed maximum maturity.
Normally, harvest occurred from mid-October through January. Some portions
of the farms had two crops grown per year. These "double cropped" areas
were harvested and sampled twice a year; mid-October through January and
April through mid-May.
Crop samples were obtained for laboratory and yield tests. For labor-
atory analysis, all the plants within a square meter area in each sampling
location were removed and composited into sterile, plastic bags to obtain
one plant sample per 65 ha area (field or pivot). Crop samples were divid-
ed into specific plant parts (i.e., seed, stem, leaves, etc.) at the labor-
atory.
The analyses performed on crop samples were determined by the type of
plant and plant part (Table B.3). Those parameters such as metals and
nutrients, which could be translocated from the soil to all parts of the
plant, were analyzed on all plant tissue samples. Bacteria, yeast and
fungi, which could contaminate exposed surfaces of crops, were analyzed on
all samples.
Irrigation Records
Documentation of the quantity of treated sewage applied to a specific
area of the farm was necessary for the interpretation of soil and crop
data. Furthermore, the records were used in assessing the economics of
domestic wastewater reuse through farming. Finally, the irrigation records
were used in assessing the exposure of participants in the Lubbock Infec-
tion Surveillance Study (LISS) to pathogens contained in aerosols generated
from the spray irrigation center pivot machines. Each farmer recorded the
daily amount of effluent pumped through a center pivot machine and the
starting and final position of the machine in the field.
Economics
The economics of land treatment were monitored through operation and
maintenance cost records provided by the City of Lubbock and the farmers
utilizing the land treatment system. The city supplied yearly summaries of
28
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the cost of treating the water supplied to each farm and the cost of oper-
ating and maintaining the pump station delivering water to the Hancock
farm. Most of these costs were divided into monthly subtotals. Yearly,
the farmers turned in their financial statements including operation and
maintenance costs of the center- pivots, electrical costs of their share of
the reservoir pumps, farming costs, and monetary returns.
THE LUBBOCK INFECTION SURVEILLANCE STUDY (LISS)
The LISS involved a four-year health watch of people residing on or
near the Hancock farm and individuals farming the Hancock sites. Further-
more, organism levels of the wastewater and aerosols generated through
spray irrigation were monitored.
The City of Wilson was the nearest community to the Hancock farm. It
was situated at the southern boundary of the farm. The population of 576
(1980.census) occupied 181 residences ranging from small two bedroom stucco
or frame bungalows to large all-brick homes. Local commerce was based pri-
marily on agriculture.
The municipal water supply for city residents was obtained from six
wells which tapped the Ogallala aquifer. A water tower and underground
tank provided storage facilities where the water was intermittently chlori-
nated manually prior to distribution. Continuous chlorination of the City
of Wilson water supply system commenced in March 1983.
All but ten of the household within the city limits were serviced by a
municipal wastewater collection and treatment system. The treatment plant
consisted of an Imhoff tank preceded by a bar screen. Plant effluent was
allowed to evaporate from a series of lagoons while the settleable solids
were removed from the tank on a monthly basis and placed in an adjacent
drying bed. Those households not connected to the municipal system had
septic tanks.
The rural portion of the study area lay primarily in Lynn County (1980
census population, 8,605), with a small portion above the northern boundary
in Lubbock County. Approximately 130 households were located in this area
in 1980 with an estimated population of 450.
29
-------
Almost every rural household obtained its drinking water from a nearby
private well which tapped the Ogallala aquifer. Treatment of domestic
wastewater was accomplished by septic tank systems in half of the rural
houses while the other half, typically the older homes, utilized cesspools.
The Hancock site was" unique in that a typical rural community with no
prior wastewater exposure was challenged by the enteric agents aetive in a
much larger urban community (Lubbock). Persons residing around the Hancock
site may have been exposed to infectious agents indigenous in the Lubbock
population but not circulating in the study area. Thus, many in the study
population may have been relatively susceptible to the pathogens in the
wastewater. A health watch of the rural community was maintained before,
during, and after periods of wastewater spray irrigation. The health watch
focused on infections detected serologically and through isolates recovered
from routine fecal specimens. To-enhance the likelihood of interpreting
observed episodes of infectionj the likely routes of introduction and
transmission were monitored.
Disease surveillance was maintained to protect the population from any
obvious untoward effects. However, the study focused on infections and the
infecting agents rather than illness in order to obtain greater objectiv-
ity, sensitivity, specificity, and etiologic evidence.
All participants were asked to provide blood samples semiannually,
usually in June and December (Figure 5). Sera were assayed for antibody
titers to .specific enteroviruses and other microorganisms known or suspect-
ed to be present in the sprayed wastewater. A seroconversion, defined as
the fourfold or greater increase in agent-specific antibody titer in simul-
taneously tested successive sera from one individual, was-considered sero-
logic evidence that the individual had been infected by the agent during
the time interval between the blood collections. Since mycobacteria were
present in the wastewater, tuberculin skin tests were administered annually
to give suggestive evidence of a non-tuberculosis mycobacterial infection.
An adult from each household and any children under 13 years of age
were designated as fecal donors. Each donor, whether well or ill, was ask-
ed to submit routine stool specimens for microbiological testing during
scheduled weeks which spanned each major irrigation period in 1982 and
30
-------
UJ
I
ui — »
8.0
6.O
4.0
2.0
to
I
— o.o
HEALTH WATCH
Blood Collections
Scheduled Fecal Specimens
Household Health Reports
and Illness Specimens
Skin Test
t
Activity Diary
ENVIRONMENTAL
MONITORING
Aerosol Sampling
Wastewater Sampling
Drinking Water Sampling
I I I I I I I
1980
M|J|J|A|S|0|N|D
I I I I I
I ii
1981
J|F|M|A|M|J|J|A|S|0|N|D
A
AA A
1982
J|F|M|A|M|J|J|A|S|0|N|b
AA
AAA
A
A
A A
1983
J|F|M|A|M|J|J|A|S|0|N|D
AA
A A
LEGEND
Activity
, Irrigation from Pipeline
, Irrigation from Reservoir
Figure 5. LISS Study Design: Time frame of monitoring in'relation to major periods of irrigation
-------
1983. A series of three 1-week fecal collection sessions were scheduled
before, during, and near the end of each irrigation period to detect
infection events occurring in the interim. Clinical bacteriological.analy-
ses were performed to isolate overt and opportunistic pathogens. Clinical
virological analyses were performed to isolate enteric viruses in the fecal
specimens by tissue culture techniques. Electron microscopic examination
was performed on about one-fourth of the routine fecal specimens to detect
a variety of virus-like particles, many of which are not recoverable by
tissue culture techniques. Detection of a specific virus by laboratory
cultivation or by electron microscopic examination was considered evidence
of a viral infection. Each non-adenovirus viral infection was regarded to
be new, unless the same agent had been recovered from the individual in the
prior six weeks.
Each household was contacted weekly by telephone for a report of any
illnesses during the prior week. When a sufficiently recent respiratory or
gastrointestinal illness was reported, the ill participant was requested to
submit a throat swab or stool specimen to identify the causative agent.
Weekly self-reports of illness and appropriate illness specimens were ob-
tained over the entire period of irrigation from January 1982 until October
1983 and over baseline periods corresponding to seasons of heavy irriga-
tion.
The types and densities of potentially pathogenic bacteria and viruses
were monitored in the wastewater, wastewater aerosol, and other environ-
mental routes of introduction and transmission. An effort was made to
determine the fluctuations in levels of every measurable infectious agent
utilized in the health watch. However, the low densities of many agents in
environmental samples necessitated reliance on indicator organisms to
establish environmental patterns. -Wastewater samples of the effluent from
the pipeline and reservoirs to be utilized for spray irrigation, and of the
Wilson effluent, were obtained and analyzed for indicator bacteria and
enteroviruses biweekly to span the major irrigation periods. Identical
analyses were conducted on the Wilson sewage to ascertain if any signifi-
cant differences existed between Lubbock and Wilson wastewaters. Baseline
wastewater samples had been obtained with the same frequency in 1981 and at
32
-------
lesser frequency in 1980 to characterize the effluents. Microbiological
screens of indigenous enteric bacteria were conducted on one sample each
from the pipeline and the reservoir per irrigation season. The purpose of
the routine wastewater samples was to document the presence, prevalence,
longitudinal pattern, and passage through the study community of viral and
bacterial pathogens possibly introduced by the wastewater. Extensive aero-
sol sampling was conducted to characterize the aerosol density of indicator
microorganisms produced by the spray irrigation of both pipeline and reser-
voir wastewater. Virus runs were also conducted to measure the density and
diversity of enteroviruses in aerosols emanating from the sprinkler rigs.
Drinking water, houseflies, and dust storms also were evaluated as other
means of introducing microorganisms into the study population.
An aerosol exposure index (AEI) was devised to measure the degree of a
participant's cumulative exposure to microorganisms in the wastewater
aerosol, relative to all other study participants during a given irrigation
period. When a number of similar infection events were observed either
serologically or microbiologically in the study population within a time
interval corresponding to an irrigation period, this infection episode was
statistically analyzed for association with wastewater aerosol exposure
using AEI. Infection incidence rates were compared among exposure sub-
groups and with baseline rates to determine the relative risk of infec-
tion.
PERCOLATE INVESTIGATION IN THE ROOT ZONE (PIRZ)
The PIRZ study investigated the impacts resulting from physical,
chemical, and biological activities in the soil root zone on percolate flow
and quality. To monitor percolate flow and possible quality changes with
depth, a lysimeter system was installed at the Hancock and Gray farms so
that percolate could be obtained at three different levels within the root
zone. Measurements were made of the precipitation and of the irrigation
waters applied to three cropping systems that were of economic importance
to the region and which exhibited a range of water and nutrient require-
ments during growth. The crops grown on each test facility site were cot-
33
-------
ton, grain sorghum, and bermuda grass.
Tray and tube non-weighing lysimeters were employed in the percolate
collection system (Figure 6). Vacuum devices were used to obtain percolate
from the lysimeters. The vacuum level maintained in the percolate collec-
tion system of these units was adjusted to levels measured by a tensiometer
located in adjacent undisturbed soil.
Replicates of the two lysimeter technique for collecting soil perco-
late were utilized on each test plot. Tubes containing undisturbed soil
cores and trays containing disturbed soils placed in contact with undis-
turbed soils were installed on each plot. Three trays, located in cavities
108 degrees apart, were placed at depths of 61, 122, and 183 cm. Pairs of
tube lysimeters were emplaced with the upper surfaces 30 cm underground so
that normal tillage operations could be conducted. Percolate was collected
from one pair of tube lysimeters at a depth of 122 cm and from the other
pair at 183 cm. One plot on each farm area had an additional pair of tube
lysimeters which collected percolate at the 244 cm depth.
An underground chamber was installed at the center of each test plot.
These chambers contained the necessary support equipment for the installed
vacuum extractors. The lysimeters were placed in the soil at varying
depths radially around the chamber and at distances far enough from it so
as not to be influenced by the chamber's interference with soil percolate
flow.
A traveling-gun irrigation system was employed to apply treated sewage
to approximately 2.5 ha of land. The amount of precipitation was monitored
with both recording and non-recording rain gauges.
Hater Collection and Analyses
The quantity of treated wastewater applied during the irrigation event
was determined by the catch-can procedure. Lysimeters were inspected
daily. The percolate volume collected in the 20 liter glass bottle which
functioned as the specific percolate storage unit for the lysimeter was
drained and measured in a graduated cylinder. Water quality analysis was
limited by the volume of percolate collected. Grab samples were collected
when a lysimeter first began percolate production; started percolate col-
34
-------
Extraction Tray
1.52m x .15m
(3 Trays will be emplaced at
each of the 3 specified depths)
Ul
Vacuum Pump
Manhole
Sample Collection
Units
Tensiometers
Tube Lysimeters
2 - 1.07m Length
2 - 1.68m Length
Buried 0.3m below surface
Figure 6. Plan of Test Facility
-------
lection again after a period of operation with no percolate collection
activity; and, by protocol, for a sample collection event.
Weekly composite samples were prepared by taking a portion of the dai-
ly collection volume from the lysimeter and compositing it with the water
composited from the previous days. The compositing of percolate samples
was accomplished by taking a constant volume sample from each daily perco-
late collection event prior to April 1983. After April, percolate samples
were composited on a volume weighted basis by taking 10 percent of the dai-
ly percolate volume for the composite sample.
The original water quality analysis is presented in Table B.4. The
parameters that were measured were reduced to a priority listing based pri-
marily on the limited sample volume collected. In April, 1983 a sampling
schedule was developed to obtain more quality data from the collected per-
colate. Based on the amount of sample present, the analyses to be per-
formed on each- type of composite sample were prioritized as follows. For
the samples not acid-fixed, the analyses were: 1) pH; 2) COD; 3) TDS; 4)
50^; and 5} alkalinity. For the acid-fixed samples they were: 1) N02+N03;
2) NH3; 3) TKN; 4) COD; 5) minerals (i.e.", Na, K, Ca, Mg); 6) Cl; and 7)
TOC.
Grab samples were taken once a week from each lysimeter that had col-
lected percolate over the previous 24-hour period. The sample analysis
priorities to be followed under the grab sample collection schedule were:
1) conductivity; 2) N02+N03; 3) orthophosphate; 4) bromide; 5) total pho-
sphorus; and 6) organic phosphorus. Also, irrigation water applied to the
test plots were to be analyzed for 1) nutrients (TKN, N02/N03, NH3, Total
P, PO^, Organic P);.2) minerals (i.e., Na, K, Ca, Mg); 3) COD; 4) TDS.
Soil Collection and Analysis
Soil cores extraction and analysis followed the same protocol as pre-
viously described in the Demonstration/Hydrogeologic Study. Three 1 .8 m
soil cores were collected from each test plot. Cores were taken only to a
depth of 90 to 107 cm on the plots at the Gray site because of the hard
caliche layer below those depths. A 7.6 cm x 120 cm flight auger was used
to obtain soil samples from the bottom of the core hole to a 183 cm depth.
36
-------
The cores were taken within 6.0 m of the ends of the lysimeter trays. Each
core was divided into 30 cm sections. Sections from the same depth at each
test plot were composited to make a sample. Soil samples obtained with the
auger were not subdivided.
Crop Collection and Analysis
The procedure used to determine the yield and quality of crops grown
on each test plot was the same as the protocol established for crop moni-
toring in the Demonstration/Hydrogeologic Study. Yield data on each plot
were calculated from crop samples taken from three subplot areas that had
been laid out parallel with the path of the traveling-gun irrigation unit
and in line with the lysimeter battery.
AGRICULTURAL RESEARCH STUDIES
Agricultural research activities conducted at the Hancock farm focused
on crop management to minimize problems associated with high hydraulic,
nutrient, and salt loading rates.
Experimental plots were established to evaluate the effect of hydraul-
ic loading rates on various crops, soil, and percolate water. Similarly,
research plots were designed and planted to determine the effect of hy-
draulic loading rates and frequency of application on salt accumulation in
soils and the ultimate impact on crops.
Hydraulic Loading Rate Studies
Cotton was planted in 4.1 m x 13.7 m test plots. Four replicates were
tested for each treatment. Treatments consisted of annu.al treated waste-
water hydraulic loading rates ranging from zero cm.ha/ha.yr to 297
cm.ha/ha.yr. A total of 13 hydraulic treatments were tested. Similarly,
grain sorghum test plots were irrigated with 0, 122, 183, 229 and 297 cm of
treated sewage/yr. Two replicate plots were established for each treat-
ment .
The investigation not only considered the production of cotton and
grain sorghum but also certain high nitrogen and water consuming crops such
as alfalfa and bermuda. Certain alfalfa test plots were irrigated with 434
37
-------
cm.ha/ha.yr in 1983 while specific common bermuda test plots had 396 cm
ha/ha.yr applied in 1983. Three fresh water control alfalfa plots were
established to differentiate the affects of increasing hydraulic loadings
on crop yield and quality from the growth response of crops and associated
quality resulting from certain constituents in the wastewater effluent.
Irrigation of test plots was minimal until a crop stand was established.
Once a stand was established, hydraulic loadings were increased to test
water tolerance of crops and nutrient utilization. The alfalfa was initi-
ally watered with fresh water and sprinklers to get the best stand possi-
ble. Irrigation of seedlings with slightly brackish water (average TDS
1,227 mg/1) may have presented germination problems.
Alfalfa was harvested every 28 to 30 days. All test plots were flood
irrigated. Each month from 12.7 to 58.8 cm of water had to be applied to
the corresponding test plot per irrigation period.
Hydraulic Application Frequency Study
The average total dissolved solids (TDS) level in the wastewater
applied to the Hancock farm was approximately 1200 mg/1. The major cation
present in the waste stream was sodium. Sodium adsorption ratio of the
effluent was about 10. Accounting for alkalinity (average concentration
344 mg/1 as CaC03), the adjusted SAR was approximately 22. Management of
salt and water in wastewater reuse systems can be greatly affected by the
crop grown, hydraulic loading and the frequency of wastewater applications.
Two operational parameters which potentially will aid in the management of
salts are the hydraulic loading rate and the frequency of application.
A solid set sprinkler irrigation system was employed which reflected
the method of irrigation used at the Hancock farm and is the most widely
used throughout the United States. Three nozzles spaced 6.1 m (20 ft)
apart on 3.8 cm (1.5 in) PVC was moved through the field to attain the
necessary irrigation. Crop samples, yield and soil samples were obtained
from within the circular irrigated areas. A four frequency by three hy-
draulic loading rate matrix was established with two crops, soybeans and
grain sorghum (Table 8). Annual, hydraulic loadings of 30, 61, and 122 cm
were scheduled with applications made at one, two, four and eight week
38
-------
TABLE 8. TREATMENT MATRIX HYDRAULIC LOADING RATE FOR TRIAL 17000
Application Treatment
Frequency Code
1
1
1
1
application 01
per week
application 02
per 2 weeks
application 03
per 4 weeks
application 04
per 8 weeks
30
(12
1
(0
2
(0
4
(1
8
. (3
cm/yr
")
.02
.4
.03
.8
.6
.6
.13
.2
Rate
cm
in)
cm
in)
cm
in)
cm
in)
Treatment 61 cm/yr
Code ' (24")
05 2
(0
06 4
(1
07 8
(3
08 16
(6
.03
.8
.06
.6
.13
.2
.26
.4
Rate
cm
in)
cm
in)
cm
in)
cm
in)
Treatment 122
Code (48
09 4.
(1.
10 8.
(3.
11 16.
(6
12 32.
(12
cm/yr
11 )
06
6
13
2
26
.4
51
.8
Rate
cm
in)
cm
in)
cm)
in)
cm
in)
VjJ
-------
intervals. As the time intervals between applications increased, the
amounts of water per application increased to maintain the scheduled yearly
loadings.
Sample Collection and Analysis
Irrigation water was derived from three sources: 1) -from the distribu-
tion pipeline as the effluent was pumped to the Hancock farm from the City
of Lubbock; 2) from the reservoir wastewater discharge; and 3) from a well
used to provide ground water for the alfalfa fresh water control plots.
In 1982 approximately 95 percent of the effluent applied to test plots
was derived directly from the pipeline, prior to the reservoirs, and 15
percent of the effluent came from the reservoirs. The following year 80
percent of the effluent was obtained from the storage reservoirs' and the
remaining 20 percent from pipelines prior to reservoir storage. A well
located adjacent to research plots was used for the fresh water source.
The fresh water source was sampled in April, August, and December of each
year. The effluent water from the City of Lubbock as the waste stream
ar-rived at the Hancock farm, and from the reservoirs was sampled monthly
during the irrigation seasons. The exact position of the effluent monitor-
ing location was usually the effluent box at the northern end of the farm
where the effluent force main from the City sewage treatment plant entered
the farm. Except for trace organic compounds, water samples were analyzed
for the same constituents monitored in the Demonstration/Hydrologic Study
(Table B.1).
Soil and crop samples were collected from each trial. The soil and
crop sampling, locations within replications (reps) of a treatment were ran-
domly selected. Soil and crop samples were composited across reps to
obtain a representative sample of each treatment.
Each year prior to pre-irrigation and after harvest, soil samples were
obtained representing each treatment and crop within a trial. Depending
upon the particular number of treatments and replicates per trial, one to
three soil cores were taken per plot, composited within a plot, and com-
posited across reps. Sample collection and constituent analysis were sim-
ilar to procedures stated previously. .
40
-------
SECTION 4
SUMMARY OF FINDINGS
DEMONSTRATION-HYDROGEOLOGIC INVESTIGATION
Gray Farm
Ground-water Levels—
An objective of expanding the Lubbock land treatment system was to
relieve the hydraulic and nutrient mass overloading experienced at the Gray
land application site. Prior to diverting treated wastewater to the Han-
cock farm, the Gray farm received up to 57,000 m-Vday of SeWRP effluent
which was used to irrigate approximately 1,200 ha (Wells et al 1979). This
was an average annual hydraulic loading of 1.7 m. Water percolation to the
ground water created a ground-water mound beneath the Gray farm^ Depth to
water ranged from 4.6 m (15 ft) to 22.8 m (75 ft). Ground-water quality
beneath the Gray farm was degraded due to water management problems and
inappropriate cropping patterns. Figure C.1 presents ground-water level
contours beneath the Gray farm in December 1981. Flow occurs from the Gray
site toward the north, east, and south. During 1983, the water levels in
most of the observation wells dropped (Table 9).~. In 1982 only 25 percent
of SeWRP's total effluent (16,650,613 m3) to be•used for irrigation was
transported to the Hancock farm. From January 1, 1983 to October 31, 1983,
the Gray farm received 11,406,287 m3 which was 69 percent of the total
effluent applied to land. During 1982 and 1983 ground water withdrawal from
beneath the Gray farm by the City of Lubbock to provide recreational water
for its citizens remained relatively constant with withdrawal rates in 1980
and 1981. Consequently, the decline in ground-water beneath the Gray farm
probably was only slightly affected by the transfer of water to the Hancock
farm. The change in cropping pattern to "alfalfa may have been the major
contributing factor to the decrease in ground water level.
Ground-water Quality—
Prior to 1982 hydraulic and nutrient overloading applied to the farm
41
-------
TABLE 9. STATISTICS OF DEPTH TO WATER IN OBSERVATION WELLS
AT GRAY SITE DURING PROJECT
Depth to Water m (ft)
Well No.
6880
6881
6882
6883.
6884
6885
6886
6887
6888
6889
6890
6891
6892
6893
6896
6895A
6895B
6895C
6895D
7000
Initial
19.9
21.5
22.9
18.9
8.5
8.2
15.2
10.7
19.8
13.7
4.6
5.1
8.5
12.1
12.6
13.8
7.9
7.7
7.7
6.9
(65.3)
(70.6)
(75.0)
(62.0)
(28.0)
(26.8)
(50.0)
(35.0)
(65.0)
(45.0)
(15.0)
(16.7)
(28.0)
(39.6)
(41.3)
(45.3)
(25.8)
(25.4)
(25.3)
(22.8)
Minimum
10.61
21.3
22.3
18.6
5.3
5.0
15.2
10.7
19.8
13.2
3.4
4.1
3.4
10.1
3.6
9.7
5.9
5.9
6.1
5.9
(34.9)
(34.9)
(73.0)
(61.1)
(17.3)
(16.4)
(50.0)
(35.0)
(65.0)
(43.3)
(11.3)
(13.4)
(11.0)
(33.0)
(11.9)
(31.7)
(19.4)"
(19.5)
(19.9)
(19.3)
Maximum
19.9
22.1
25.6
21.0
10.7
10.1
16.7
13.2
21.3
14.4
5.8
6.1
' 12.2
12.1
15.0
13.8
8.3
8.3
8.7
8.3
(65.3)
(72.5)
(84.1)
(68.8)
(35.1)
(33.0)
(54.7)
(43.2) .
(70.0)
(47.4)
(19.1)
(20.0)
(40.0)
(39.8)
(49.1
(45.3)
(27.2)
'(27.2)
(28.4)
(27.2)
Final
17.7
21.5
22.2
18.9
9.2
8.4
16.5
12.8
21.2
14.3
4.3
5.6
8.9
11.3
12.8
9.8
8.0
8.0
8.2
7.9
(58.1)
(70.5)
(73.0)
(62.0)
(30.2)
(27.6)
(54.1)
(42.0)
(69.5)
(46.9)
(14.0)
(18.5)
• (29.2)
(37.0)
(42.0)
(32.0)
(26.2)
(26.2)
(26.8)
(26.0)
42
-------
had increased the quantity of ground water at the expense of ground-water
quality. Table 10 presents the percent of well water samples collected
from the Gray wells which contained constitutents equaling or exceeding
drinking water standards. Due to improper nitrogen management on the farm,
sufficient nitrate-nitrogen was leached to the ground water to create water
quality problems (>10 mg N/l) throughout the entire aquifer beneath the
farm. Several water samples contain Se concentrations greater than the
drinking water maximum constituent level (MCI) (0.01 mg/1). Iron and man-
ganese levels consistently equaled or exceeded recommended secondary con-
stitutent levels of 0.3 mg/1 and 0.05 mg/1, respectively. During the base-
line period hydraulic overloading leached salt from and through the soil
profile thereby increasing IDS, SO^ and Cl levels in the ground water above
recommended secondary constituent levels with regard to drinking water
sources.
The range of the average concentration of.specific water quality con-
stituents contained in the ground water beneath the Gray farm during the
baseline monitoring period (June 1980 to February 1982) and the irrigation
monitoring period (February 1982 to October 1983) is presented in Appendix
C. (Table C.1).
Nitrogen—Prior to pumping water to the Hancock farm, the average
N02+N03-N levels in the ground water beneath the Gray farm ranged from 5.05
mg/1 to 35.89 mg/1. Figure 7 illustrates that the higher ground-water
N02+N03 were experienced in areas which were row watered or flood irrigated
and wells down gradient from these areas. Once SeWRP's effluent was pumped
to the Hancock farm, ground-water N02+N03-N concentrations beneath the Gray
farm ranged from 0.77 mg/1 to 33.43 mg/1. Comparison of the average base-
line and irrigation monitoring period nitrate data showed a nitrate de-
crease in 17 of 27 monitoring wells while five wells (6852, 6855, 6885,
6864, and 6883) had an increase in average nitrate levels. Excessive pre-
cipitation (approximately 35 cm) in May and June 1982 caused surface runoff
which inundated a few poorly sealed well casings producing a pulse increase
in total Kjeldahl nitrogen (TKN). During the baseline period, TKN concen-
trations varied from 0.28 mg/1. to 6.97 mg/1. Once water was diverted from
43
-------
TABLE 10. PERCENT OF GRAY FARM WELL WATER SAMPLES WHICH EXCEED OR EQUAL
DRINKING WATER STANDARDS FOR THE FOLLOWING PARAMETERS
Total Number of Wells = 25
Maximum Constituent Level
Date
06/25/80
08/19/80
09/25/80
01/08/81
03/27/81
06/02/81
10/28/81
11/02/81
01/27/82
05/27/82
10/11/82
11/01/82
05/19/83
10/10/83
*Values
No. of
Wells
11
9
24
. 25 '
1
24
19
3
25
23
20
5
25
25
AS
0
0
0
0
0
0
. 0
0
0
0
0
0
4
0
BA
0
0
0 .
0
0
0
0
0
0
0
0
0
0
0
CD
9
0
0
0
0
4
0
- 0
0
0
0
0
0
0
CR
0
11
0
0
0
0
0
0
0
0
0
0 ..
0
0
PB HG
0 27
11 11
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
N03*
73
100
79
84
100
83
74
33
84
74
55
60
60
52
SE
0
0
0
0
0
4
5
33
0
0
5
0
4
0
AG
0
0
0
0
0
0
0
0
0
0
0
0
0
0
reported as nitrogen
Recommended Secondary
Date
06/25/80
08/19/80
09/25/80
01/08/81
03/27/81
06/02/81
10/28/81
11/02/81
01/27/82
05/27/82
10/11/82
1 1 /01 /82
05/19/83
10/10/83
No. of
Wells
11-
9
24
25
1
24
19
3
25
23
20
5
25
25
Constituent
CL
55
89
63
84
100
83
68
33
80
78
65
80
76
76
Levels
CU
0
0
0
0
0
0
0
0
0
0
0
0
0
0
FE
18
0
0
12
100
13
26
33
12
43
35
100
4
72
MN
82
0
0
8
100
13
26
33
16
17
15
30
16
12
S04 TDS
64 100
7 100
4- 92
56 96
0 100
63 96
53 79
0 67
60 92
48 91
45 80
60 100
64 88
36 88
ZN
0
0
0
0
0
0
0
0
0
0
0
0
0
0
44
-------
Well
£-:: Water
1 cm = O.27 km
Figure 7. Nitrate Concentration (mg/1) in Weil Water under Gray Farm, Baseline Period, 1981-1982
-------
the Gray farm to the Hancock farm, average TKN levels ranged from 0.20 mg/1
to 7.65 mg/1.
Phosphor us--Aver age total phosphorus (TP) levels in the ground water
beneath the Gray farm ranged from 0.10 to 3.49 mg/1 during the baseline
period (Table C.1). During the irrigation period, from February 1982 to
October 1983, ground wate'r TP levels generally remained relatively stable
with average concentrations ranging from <0.07 to 1.94 mg/1. Eighteen
wells contained water which dropped in TP levels during the irrigation
period.
Organic Carbon—Ground water COD measurements were quite variable from
June 1980 through October 1982 and appeared to stabilize during 1983. Dur-
ing the baseline and irrigation periods, average COD values ranged from
27.2 mg/1 to 125.4 mg/1 and 11.4 mg/1 to 100.3 mg/1, respectively. Median
COD values were from 12.1 mg/1 to 159.1 mg/1 from June 1980 to February
1982 and 10.3 mg/1 to 46.9.mg/1 during the irrigation period. Approximate-
ly 80 percent of the Gray wells contained less than average COD in their
respective ground water during.the irrigation period compared to the base-
line COD concentrations. Similarly, ground water TOC concentrations de-
creased from baseline period through the irrigation period.
Minerals—The salt management procedure employed at the Gray farm
prior to transporting water to the Hancock farm was leaching. The average
concentration of total dissolved solids (TDS) in the ground water beneath
the Gray farm varied from 1,010 mg/1 to 2,271 mg/1.
Calcium, magnesium, potassium, and sodium salts were the primary con-
tributors to the ground-water dissolved solids beneath the Gray farm. The
average ground-water calcium levels ranged from 47.7 mg/1 to 161.7 mg/1
during the baseline period. No significant (a = 0.05) differences in
ground-water calcium concentrations were determined when comparing the data
obtained prior to February 1982 and the data from February 1982 to October
1983. A comparison of average ground-water calcium levels computed for the
baseline and irrigation periods, however, does indicate a slight increase
in calcium levels in 72 percent of the wells. Furthermore, magnesium con-
centrations increased slightly in 19 of 25 wells. Average magnesium concen-
46
-------
trations were from 21.8 mg/1 to 137.6 mg/1 from June 1980 to February 198.2
and from 38.5 mg/1 to 148.7 mg/1 during the irrigation period.
Associated with the increase in Ca and Mg in the ground water was a
decrease in Na levels in 15 of 25 wells. . The combined reduction in Na and
increases in Mg and Ca produced a decrease in SARacji in 17 wells. During
the baseline period the average SARacj-j of ground water from 25 wells
exceeded 9 with well 6893 exhibiting the highest SARadj value of 23.9.
Severe sodic problems would develop in the soils of adjacent farms which
utilized this ground-water source for irrigation. As expected, ground
water beneath the farm areas which were historically irrigated by flood or
ridge and furrow method (row water) contained the higher, sodium levels. In
1982 the cropping pattern was changed and alfalfa became the primary crop
grown. A more even and reduced hydraulic distribution of water over the
entire farm associated with higher evapotranspiration reduced leaching of
sodium from the upper soil profile.
During the irrigation period, significant increases in ground-water
iron concentration were measured in several wells. Saturated soil condi-
tions in May and June 1982 caused reduction of iron to soluble ferrous iron
and subsequent percolate water transported increasing quantities of ferrous
iron to the ground water. Percolation resulting from heavy precipitation
events in May and August/September 1981 leached sufficient quantities of
iron to the ground water to exceed or equal drinking water standards.
Major anions associated with the salts were chlorides and sulfates.
Average chloride concentrations ranged from 208 mg/1 to 535 mg/1 during the
baseline monitoring period and 154 mg/1 to 686 mg/1 during the irrigation
period. Before effluent was pumped to the Hancock farm, average ground-
water sul fate concentrations varied from 149 mg/1 to 795 mg/1. Once the
hydraulic loading was reduced, 148 mg/1 to 399 mg/1 was the range of
average ground-water sulfate (504) concentrations measured in the ground
water beneath the Gray farm. Use of the ground water located beneath the
flood or row water irrigated areas for sprinkler irrigation of alfalfa and
grain sorghum may cause foliar injury.
Trace Metals—The majority of trace metals analyzed in each water sam-
47
-------
pie were at low concentrations. This was anticipated since the irrigation
stream contained low levels of trace metals and the soil matrix had the
ability to remove most metals. Nonetheless, certain metals did increase
significantly in the ground-water samples obtained from certain wells and/
or equaled or exceeded drinking water MCls. The data show that trace
metals present in the ground water posed no potential public health risk.
With the alkaline soils which existed at the Gray farm, anionic heavy
metals such as As and Se were more soluble and consequently an apparent
association was observed with rainfall events and slight As and Se increase
in the ground water. Colloidal particulates entering the well casing dur-
ing construction or after heavy rainfall events may have caused slight
pulse increases in Pb, Cr, Cd, and Co concentration in ground water ob-
tained from a few wells.
Priority Organic Pollutants—The ground water beneath the Gray farm
contained very low levels of specific priority organic pollutants (POP)
assayed. Contamination of ground water by priority organic pollutants was
not a problem during the study period. The soil matrix was very efficient
in removing and biologically degrading these organics.
Statistical analysis of propazine'levels obtained from wells 6884 and
6892 showed an increase in propazine concentration during the irrigation
period. Propazine was a common herbicide used to control weeds in grain
sorghum crop production. Consequently, the small increase in propazine
could have been attributable to leaching of the herbicide during the May
precipitation or transport of a small quantity of particulates containing
propazine directly into the well or through the gravel packing surrounding
the well casing.
Bacteriological data—Bacterial indicator organisms, total coliform,
and fecal streptococci were assayed in each water sample to determine the
potential presence of pathogenic organisms. Salmonella was isolated in
four wells during the baseline period. Three of five Salmonella isolations
were measured during the fall 1981. Contamination of these wells by Sal-
monella and the indicator organisms was associated with heavy rainfall
events. Similarly, heavy precipitation in May and June 1982 caused flood-
48
-------
ing of well 6884 which introduced Salmonella to water contained in the
poorly sealed well. The presence of Salmonella in this water sample was
the only isolation measured from February 1982 to October 1983.
Soils—
The Gray soils contained a higher percentage of coarse material
throughout the upper 122 cm of the profile than measured in the soil pro-
file at ,the Hancock farm. The predominate soil texture within the upper 30
cm of the profile was sandy loam. Sandy clay loams existed from a depth of
30 cm to 91 cm. Soil texture at depths greater than 122 cm varied primar-
ily from clay to clay loams. An indurated caliche soil was observed at
depths from 40 to 183 cm.
Nitrogen—The Gray farm crops were predominantly cotton in 1981 and
alfalfa in 1982 and 1983. Nitrate nitrogen concentrations were fairly
uniform throughout the entire 183 cm soil depth in 1981. Analysis of soils
in 1983, however, indicated a decrease in nitrate levels in the upper 91 cm
which resulted from greater nitrogen uptake by alfalfa. Ammonia nitrogen
existed primarily in the top 30 cm of soil. No appreciable change in ammo-
nia concentrations was observed between soil samples collected in 1981 and
1983. The bulk of the soil nitrogen was incorporated in organic matter. A
reduction of organic nitrogen from the 1981 levels was measured in 1983. A
nitrogen balance on the soil indicated that nitrogen uptake by crops grown
beneath the center pivot irrigation machine was the major mechanism govern-
ing nitrogen losses. Deep percolation of inorganic nitrogen beneath the
center pivot machines was not a major mechanism of nitrogen loss in 1982 or
1983. The results of the nitrogen mass balance for the flood irrigated
area showed deep percolation of nitrates to the ground water remained a
significant process for the loss of nitrogen from the soil profile in the
flood or row water areas. The ground-water quality data also substantiate
this conclusion.
Phosphorus—Phosphate-calcite reactions were probably an important
mechanism for the removal of phosphorus from the soil solution. A total
phosphorus mass balance showed annual phosphorus removal by crops in 1981,
49
-------
1982 and 1983 was less than the mass applied through irrigation. Only 33
percent of the applied TP was consumed by crops. The remainder was proba-
bly fixed into the soil matrix.
The phosphorus uptake by wheat (flood irrigated) was only 12 percent
of the estimated 1,072 kg/ha applied from 1981 through 1983. Fixation of
phosphorus may have been the major mechanism which governed phosphorus re-
moval from the soil solution.
Minerals—Total dissolved solids in the soil matrix beneath the center
pivot machines increased gradually with depth in 1981; whereas, frequent
leaching of salts in the wheat -areas produced a more uniform TDS concentra-
tion throughout the entire soil profile. A TDS mass balance indicated
flood and row irrigation and precipitation leached salts below a depth of.
183 cm during the period from spring 1981 through 1983. Chloride and sul-
fate mass balances further substantiated the deep percolation of anions
past 183 cm depth in the flood irrigated areas. The salts applied to cot-'
ton and alfalfa areas, however, were somewhat retained in the soil profile.
Increases in TDS levels measured in 1983 did not appear to be associ-
ated with increases in sodium ion. A slight increase in the average sodium
concentration was measured at depths of 61 and 91 cm in 1981. Sodium lev-
els were fairly uniform throughout the soil profile in 1983. Based on a
cation exchange capacity (CEC) in the upper 30 cm of 22 meq/100g an ex-
changeable sodium percentage (ESP) of approximately seven was computed for
sodium in the top 30 cm beneath the spray irrigated area. Therefore, sod-
ium levels were maintained sufficiently low by leaching to prevent sodic
conditions (ESP <15) in the soil. Similarly, the ESP value for 1981 and
1983 in the upper 30 cm of the flood or row water areas was seven.
Trace Metals--Table 11 presents the total average mass of specific
trace metals applied by flood and row irrigation. Over a three year period
from 1981 through 1983, input of trace metals through irrigation to the
soil was low. Compared to the concentration of metals in the soils, the
concentration of metals in the crop tissue was negligible. Anionic metals
such as arsenic and chromium (VI) probably were transported by percolate to
depths greater than 91 cm within the alkaline soils. In addition, barium,
50
-------
copper and nickel possibly leached beyond the 91 cm soil depth. Possible
accumulation of cadmium, cobalt and lead occurred in the upper 91 cm of
soil in the flood irrigated areas. Special variability had the most impact
on deficiencies in trace metal levels measured in 1981 and 1983.
Priority Drganics Pollutants—The majority of soil samples analyzed
for specific priority organic compounds, contained levels below their
respective detection limits. In both the spray and flood irrigated areas,
solvents such as benzene and chloroform existed throughout the 183 cm soil
profile in 1981.
TABLE 11. TRACE METALS MASS BALANCE ON SOILS COLLECTED
FROM FLOOD IRRIGATED AREA
Trace
Metal
As
Ba
Cfl
Co
Cr
Cu
Pb
Ni
Mass Applied
(kg/ha)
1.887
26.96
0.276
0.358
4.820
5.167
2.962
4.235
Mass in Soil
(kg/ha)
1981
85.0
2351
2.56
36.8
593.7
202.2
34.4
175.0
Profile
1983
26.9 .
1267
4.40
90.1
189.4
83.3
101.4
118.6
Change in
Soil Profile
(kg/ha)
-58.1
-1084
+1.84
+53.3
-404.3
-118.9
+67.0
-56.4
Unaccounted
Mass (kg/ha)
-60.0
-11.11
+1.56
+52.9
-409.1
-124.1
+64.3
-60.6
Benzene levels decreased to levels barely exceeding detection limits in
1983. In 1983, however, chloroform levels appeared to have increased above
baseline levels. Furthermore, chloroform concentration increased with
depth.
Carbon tetrachloride and tetrachloroethylene were not measured at con-
centrations above detection limits in 1981, but were detected at levels
exceeding analytical limits in practically all samples collected from flood
and spray irrigated areas in 1983.
51
-------
Chlorinated aniline, compounds such as 2,3-dichloroaniline and 3,4-
dichloroaniline may have been derivatives of herbicides or fungicides. In
general, 2,3-dichloroaniline was more prevalent at soil depths from 91 cm
to 183 cm beneath the center pivot machines in 1983 than in 1981. Further-
more, less amounts of chlorinatedanilines were detected in the flood irri-
gated soils.
Acenaphthylene and the various dichlorobenzene forms in the soils may
have been derived from application of insecticides. These organic com-
pounds existed primarily in the upper 61 cm of the soil profile.
The presence of trace organics in the soil profile in 1981 and 1983
may have been directly related to the mass loadings of specific organics
through flood irrigation of wheat. Decreased organic mass loadings by
spray irrigation, however, reduced the potential of residual levels of pri-
ority organic compounds in 1983 being derived solely from irrigation.
Bacteriological Data—Total coliform, (-TC) fecal coliform (PC) and
fecal streptococcus (FS) were primarily retained in the top 30 cm of soil.
Furthermore, FS was detected at greater concentrations in the spray irri-
gated areas in 1983 than in 1981. Certain soil samples obtained from the
flood irrigated areas contained concentrations of TC and FS exceeding
detection limits at depths of 183 cm.
Fungi and actinomycetes concentrations within the soil profile were
relatively constant throughout the farm and the monitoring period. Changes
in hydraulic loading or cropping patterns did not appear to affect the num-
ber of actinomycetes or fungi present throughout the entire 183 cm soil
core.
Crops—
Cotton yields prior to 1982 equaled or exceeded irrigated Lubbock
County yield averages of 434 to 457 kg/ha in 1980 and 1981, respectively.
Alfalfa yields in 1982 (crop establishment year) ranged from 1.8 to 2.7
metric tons/ha which was relatively low compared to a normal range of 5.4
to 7.0 metric tons/ha. The yield reduction was partially due to 1) delays
in watering, thereby delaying regrowth; 2) poor stand establishment; and 3)
weed competition. Weed competition also affected the quality of the hay
52
-------
harvested; thus lowering the crop's marketability. The 1983 alfalfa yields
on the Gray farm were again reduced by delays in watering which reduced the
number of cuttings. Normally, five to seven cuttings of alfalfa are ex-
pected in the Lubbock area (Texas A & M Extension Service). The Gray farm
produced three to four cuttings. Alfalfa yields were slightly improved
over 1982 values. Soybean yields averaged 2,494 kg/ha (37 bu/ac). Wheat
yields from the Gray farm were difficult to determine since no grain har-
vest was planned and forage harvest was accomplished by grazing. Analysis
of crop tissue indicated macro and micro nutrients were within normal
.ranges. Potential toxic trace metals did not. appear to accumulate in the
crop tissue.
Hancock Farm
Ground-water Levels—
The saturated thickness of the aquifer beneath the Hancock farm was
less than'6.1 m (20 ft). Depth to water varied from 24.4 to 36.6 m (80 to
120 ft). In 1981 ground-water flow occurred toward both the north and the
south from a ridge through the center of the property (Figure C.2).
Ground-water levels increased beneath the Hancock site during the per-
iod from January 1982 to October 1983 (Table 12). Ground-water recharge
from surface runoff contained in the moat areas surrounding the reservoirs
and through coarse material along the fringes of the playa lakes most like-
ly caused the water level rises beneath the farm. Irrigation amounts dur-
ing the study period were far less than crop evapotranspiration rates;
consequently irrigation . does not appear to be a source of ground-water
recharge.
Ground-water Quality—
Prior to land application of treated wastewater at the Hancock farm,
the range of average concentration of constituents measured in the ground
water beneath the Hancock farm is presented in Table C.2. Several well
water samples contained levels of contaminants which exceeded or equaled
drinking water maximum constituent levels (Table 13).
Nitrogen--Associated with the deep percolation of rainfall surface
53
-------
TABLE 12. STATISTICS OF DEPTH TO WATER IN OBSERVATION WELLS AT
HANCOCK SITE DURING PROJECT
Depth to Water m (ft)
Well No.
10112
10211
10521
10721
10731
10821
10842
10931
10932
11032
20112
20243
20711
20721
20842
21141
21152
21234
21323
30312
40231
40331
Initial
34.0
37.0
24.2
25.9
24.7
21.9
26.9
21.5
20.6
28.4
35.7
41.5
31.4
27.4
30.5
27.4
26.3
26.3
29.6
32.0
30.2
29.6
(111.4)
(121.5)
( 79.3)
(- 85.0)
( 81.0)
( 72.0)
( 88.1)
( 70.4)
(67.7)
( 93.1)
(117.0)
(136.0)
(103.0)
( 90.0)
(100.1)
( 90.0)
( 86.2)
( 86.3)
( 97.1)
(105.0)
( 99.0)
( 97.0)
Minimum
27.9
36.5
22.9
19.1
19.0
18-. 9
20.6
17.4
13.4
27.2
33.7
41.5
31.1
24.8
25.3
25.0
22.0
22.7
29.0
31.4
29.6
28.2
- ( 91.6)
(119.9)
( 75.0)
( 62.6)
( 62.4')
( 67.7)
.( 62.0)
( 57.0)
( 43.9)
('89.3)
(110.7)
(136.0)
(102.0)
( 81.3)
( 83.0)
( 81.9)
( 72.1)
( 74.4)
( 95.0)
(103.1)
( 97.0)
( 92.7)
Maximum
34.4
40.3
25.8
28.1
25.2
27.3
27.3
21.5
20.7
28.7
36.1
44.6
32.4
29.5
30.7
27.7
26.3
26.6
30.2
32.4
30.8
29.6
(113.0)
(132.1)
( 84.8)
( 92.2)
( 82.8)
( 72.0)
( 89.7)
( 70.5)
( 67.9)
( 94.3)
(118.3)
(146.3)
(106.3)
( 96.7)
(100.8)
( 91 .0) "
( 86.4)
( 87.3)
( 99.1)
(106.3)
(101.0)
( 97.0)
I
32.6
36.6
22.9
19.1
19.0
18.9
24.9
18.3
15.5
27.4
34.2
41 .6
31.2
24.8
28.0
25.0
22.4
22.7
29.0
31.5
29.8
28.9
•inal
(106.8)
(120.0)
( 75.0)
( 62.6)
.( 62.4)
( 62.0)
( 81.8)
( 59.9)
.( 51.0)
( 90.0)
(112.2)
(136.4)
(102.2)
( 81.3)
( 92.0)
( 82.0)
( 73.5)
( 74.4)
( 95.1)
(103.4)
( 97.7)
( 94.8)
54
-------
TABLE 13. PERCENT OF HANCOCK FARM WELL WATER SAMPLES WHICH EXCEED OR EQUAL
DRINKING WATER STANDARDS FOR THE FOLLOWING PARAMETERS
Total Number of Wells =27
Maximum Constituent Level
Date
07/22/80
10/30/80
11/11/80
01/26/81
03/27/81
06/11/81
10/29/81
11/18/81
01/18/82
06/14/82
09/22/82
11/10/82
02/15/83
03/14/83
05/09/83
07/20/83
09/15/83
No. of
Wells
12
7
16
23
2
24
2
22
27
27
25
2
7
12
27
1
27
AS
0
0
0
0
0
0
0
5
0
0
0
0
0
0
0
0
0
BA
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
CD
17
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
CR
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
PB
8
0
0
0
0
0
0
0
0
4
0
0
0
0
0
0
0
HG
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
N03
8
0
25
0
0
13
0
27
4
11
12
0
57
8
15
0
7
SE
0
29
0
0
0
4
50
18
19
15
0
0
0
0
15
0
11
AG
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
(continued)
-------
Table 13, continued
Recommended
Date
07/22/80
10/30/80
11/11/80
01/26/81
03/27/81
06/11/81
10/29/81
•* 11/18/81
01/18/82
06/14/82
09/22/82
11/01/82
02/15/83
03/14/83
05/09/83
07/20/83
09/15/83
Secondary Constituent Levels
No. of
Wells
12
7
16
23
2
24
2
22
27
27
25
2
7
12
27
1
27
CL
0
0
0
0
0
0
0
9
0
4
0
0
0
0
4
0
7
CU
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
FE
25
14
0
22
0
4
100
73
85
96
92
100
0
0
59
0
89
MN
67
71
25
30
100
42
50
45
52
52
44
100
0
0
30
0
48
so,
0
0
0
0
0
4
0
0
0
4
8
0
14
0
4
0
4
IDS
8
0
0
0
0
4
0
0
4
.7
0
0
29
0
7
0
11
ZN
0
0
0
0
0
4
0
0
0
0
0
0
0
0
0
0
n
-------
runoff captured in playa lakes or moat areas surrounding the storage reser-
voirs was the leaching of nitrate nitrogen to the ground water. Nitrate
levels in water obtained from seven wells, which were adjacent to surface
runoff collection areas, increased after heavy precipitation events. The
rapid increase in ground-water nitrate concentrations may have resulted
from migration of percolate around poorly sealed well casings to the
ground water. Most of the ground-water samples collected during the moni-
toring period contained less than one ppm TKN.
Phosphorus--During the baseline monitoring period, average TP levels
measured in the ground water ranged from 0.19 mg/1 to 0.58 mg/1. -The aver-
age ground-water TP concentration from February 1982 through October 1983
ranged from 0.02 mg/1 to 0.41 mg/1. The data indicate a decreasing trend
in TP from baseline through irrigation. This decrease was primarily due to
a decrease in organic phosphorus in the ground-water.
There appeared to be an increase in TP and PO^ in most wells in June
1982. During the baseline period ground-water P04 levels ranged from <0.01
to 0.22 mg/1. From February 1982 to October 1983, the majority of water
samples analyzed contained less than 0.10 mg/1 orthophosphate phosphorus.
Organic Carbon—Median COD concentrations during the baseline and
irrigation periods ranged from 4.1 mg/1 to 94 mg/1 and 3.8 mg/1 to 88 mg/1,
respectively. High COD levels were primarily the result of soil entering
the well during construction. Ground-water organic carbon levels decreased
during the period from June 1980 to October 1983.
Minerals—Pripr to transporting SeWRP's effluent to the Hancock farm,
the average TDS in the ground water beneath the farm ranged from 363 mg/1
to 989 mg/1. As was observed with increases in ground-water nitrate
levels, increases in TDS in water obtained from a few wells appeared to be
associated with heavy precipitation events.
Comparison of baseline and irrigation period average sodium adsorption
ratio (SAP) for the water extracted from each well indicate a general
change in composition of salts. From June 1980 to February 1982, the aver-
age adjusted SARs (SARacy) of the ground water ranged from 3.0 to 8.4. To
prevent the creation of sodic soils, irrigation water should have an SARa(jj
57
-------
below six (Stromberg and Tisdale 1971). Eleven wells contain water -with
average SARacn less than six. Increasing problems, however, may occur with
SARac|j from six to nine. Computed SARacjj values for ground water obtained
from 24 wells were between six and nine. Therefore, no severe problems
with water penetration were indicated by the data. During the irrigation
monitoring period, SARacjj values ranged from 2.1 to 11.0. Approximately 60
percent of the wells demonstrated an increase in Ca and Mg, and Na was re-
duced in 79 percent of the wells during the irrigation period. Therefore,
in 18 wells the SARacjj was lowered during the irrigation period.
In general, no significant changes in ground-water chloride ion con-
centrations was detected throughout the monitoring period. A significant
increase in Cl ion levels was observed in the monitoring wells adjacent to
the moat area surrounding reservoir 2. During the baseline period, chlor-
ide levels ranged from 22 mg/1 (0.6 meq/1.) to 246 mg/1 (6.9 meq/1) and from
17 mg/1 (0.4 meq/1) to 345 mg/1 (9.7 meq/1) from February 1982 to October
1983. Chlorides present in the ground water would not cause foliar injury
to crops grown on the Hancock farm which were primarily cotton, grain sor-
ghum, and alfalfa.
Trace Metals—As previously stated, trace metals were not a major con-
cern due to the limited industrial waste water contribution to SeWRP's sew-
erage load and the "ability of the alkaline calcareous soil profile to ade-
quately remove and render relatively insoluble most trace metals. Trace
metals posed no potential agricultural or public health problems during the
project monitoring period.
Priority Organic Pollutants—In general, slow rate land application of
organic compounds contained in municipal waste water should pose no hazard
to ground water, soil microbial community and vegetation (Overcash 1983,
Davidson et al 1980). The ground-water data confirms this statement. Major
priority organic compounds measured in the ground-water samples were
phthalates (i.e., dibutylphthalate, diethylphthalate, diisooctylphthalate).
Phthalates are used as plasticizers in polymers and migrate quite readily
to the surrounding environment. Consequently, phthalate contamination may
have been an artifact of well construction, sample collection, and presence
58
-------
of plastics within the laboratory.
Ground water in well 10521, 10931, 10721, 30312, and 10721 experienced
a pulse increase in atrazine in 1983. Average atrazine concentrations in
wells 10521,. 10931, 10721, 30312, and 10731'were all less than 2.0 ppb dur-
ing the baseline period and 13.9 ppb, 2.5 ppb, 11.9 ppb, 10.8 ppb, and 12.6
ppb, respectively, from February 1982 to October 1983. Atrazine was used
to kill weeds and grasses in borrow ditches, and around each center pivot
irrigation machine. In addition, patches of weeds surrounding playa lakes
or extending into fields were treated with atrazine.
Bacteriological data—During the baseline period, indicator organisms
were isolated in water from more than 85 percent of the wells. A small
biochemical study identified the fecal streptococci organisms to have been
possibly S. faecalis subspecies liquefaciens and not of human source. A
potential source of Salmonella, fecal coliform and fecal streptococci was
most likely rodents which burrowed beneath concrete pads surrounding well
casings. Detection of Salmonella in' water samples decreased during the
irrigation period. In general, very little difference was observed between
bacteriological data obtained during the baseline and irrigation monitoring
periods.
Soils—
At .the Hancock farm, the soil texture within the upper 30 cm (1 ft) of
the soil profile was generally sandy clay loam. Clay to clay loams domi-
nated the soils from a depth of 30 cm to 122 cm (4 ft) within the profile.
The majority of soils from 122 cm to 183 cm (6 ft) were clays. An indurate
layer of calcium carbonate (caliche) existed within the soil profile at a
depth of 61 cm to 183 cm throughout the farm.
Soils at the Hancock farm were alkaline and calcareous with pH values,
within the upper 183 cm, of seven to eight. Cation exchange capacities
(CEC) were greater than 20 meq/100 g (average 22.4 meq/100 g + 3.7) which
were characteristic of the clay/clay loam soils.
Nitrogen—The bulk of the nitrogen in the soil profile was in the
organic form, which appeared to decrease linearly through the upper 152 cm
of the profile. Carbon to nitrogen (C/N) ratios of the organic matter
59
-------
ranged from three to 47 with only three percent of 235 cores having a C/N
ratio greater than 20. C/N ratios less than 22 are associated with net
mineralization and ratios higher than 22 indicate net immobilization. The
average C/N ratios of the effluent pumped to the farm and from the reser-
voirs were 4.0 and 5.9, respectively. Therefore, net mineralization-of
organic nitrogen predominated within the soil profile. Nitrate-nitrogen
was the major inorganic nitrogen form within the soil profile. Nitrate
lenses were detected within the lower 91 cm of several soil cores (Figure
8). Low moisture conditions due to the semiarid climate of the South
Plains may have inhibited decomposition of organic matter and denitrifica-
tion of nitrate-nitrogen.
Nitrogen mass balances were conducted on the soil-crop matrix. The
spacial variability of the data in conjunction with the error associated
with the assumptions imposed on the model produced highly variable results.
At the lowest annual hydraulic loading (42.2 cm) the processes included in
the nitrogen model described most of the nitrogen transformation within the
soils (Figure 9). Increased nitrogen losses due to denitrification, vola-
tilization, or possible leaching were not accounted for in the mass balance
at the 52.2 cm/yr irrigation loading.
The nitrogen mass balance model when applied to the area of the farm
irrigated with an average hydraulic loading of 68.9 cm/yr, predicted inor-
ganic nitrogen mass in the profile of 302 kg/ha compared to a measured
average of 277 kg N/ha. In general, the assumption that, inorganic nitrogen
was not leached from the upper 183 cm of the profile appeared to be sub-
stantiated by the nitrogen mass balance.
Phosphorus—Phosphate-calcite reactions were believed to be a major
factor in the removal of phosphorus from the soil solution. The soil pro-
files throughout the farm denote a general decrease in TP from 1981 levels
to 1983 levels.
A phosphorus mass balance on the soils at each hydraulic loading show-
ed that the crops utilized more phosphorus than was applied in 1982. In
1983, the mass of phosphorus removed by crops was less than applied. Fur-
thermore, the amount of phosphorus removed by the cotton was less than the
60
-------
o
=»*.
o
o.
OJ
o
tO
J—o
Q_ c\J
o
o
oo
o
=f_
o
o
Hancock Farm
D Soil Core 02003
O Soil Core 05071
A Soil Core 06043
0.00
Figure 8.
0.03
0.07
0.10
o.m
0.17
I
0.21
-i
NITRITE + NITRATE (MG N/G)*1O
Illustration of Nitrite+Nitrate Lenses in Hancock Soil, 1981
0.2U
0.28
-------
N in Root Zone in 19U1
N from Organic N in Root Zone
N Applied in Effluent
Removed by Crop
Denitrification
Measured level in Profile 1983
Difference between Measured and
Predicted - Potential Leaching
400
300
(0
^200
c
0
O)
o 100
4-1
z
'c +
O
£
100
200
300
400
, 42.2cm ^52. 2 cm , 68.9cm
9
\
I !
! **
i
i
•
h
1
!Si
1
1
1
'
S
•I
| S \
. _
IS
• S
i! 1
NITROGEN
' SOURCES
1
1
1
I
NIT
LO
1
1
ROGEN
SSES
Figure 9. Inorganic Nitrogen in 183 cm Profile at the Hancock Farm
62
-------
normal crop requirement of the 15 kg/ha.yr to 34 kg/ha.yr.
Minerals—In general, salts accumulated in the upper 122 -cm of the
profile. In the double cropped areas (68.9 cm hydraulic loading) IDS lev-
els increased at the 152 cm and 183 cm depths, where no increase at these
depths was detected in soils irrigated with less amounts of water. Assum-
ing negligible crop uptake of salts, a mass balance of the IDS in the soil
profile, indicated the majority of applied salts were retained within the
183 cm soil zone.
Sodium salts composed most of the salt load to the Hancock farm. A Na
mass balance indicated that sodium was retained in the soil profile. The
exchangeable sodium percentage (ESP) was approximately two in the upper 30
cm in 1981 and was increased to a maximum of six in the double cropped
areas. Future use of SeWRP's effluent without proper management of sodium
in the soil profile may produce sodic soil (ESP > 15) in the upper 30 cm.
Both Cl and SO^ ions accumulated within the upper 122 cm of the soil
profile. Average Cl levels ranged from 12 to 70 mg/1 in soil samples col-
lected in 1981 and 38 to 162 mg/1 in soils obtained in the fall of 1983 and
winter of 1984. The Cl concentration increased throughout the entire 183
cm soil profile beneath areas where the highest Cl mass loading was ap-
plied. The majority of soils analyzed contained Cl levels at the lower end
of the normal range of 50 to 500 mg/1.
Trace Metals—Due to the low levels of metals in the wastewater, trace
metals were not considered to pose a problem to crops or public health. A
mass balance computed on the trace metals (Table 14) indicated the change
in metals levels from 1981 to 1983 was not attributable to irrigation.
Priority Organics--The majority of samples analyzed for priority or-
ganics in 1981 and 1983 contained organic compounds at levels below detec-
tion levels of the analytical procedure. Atrazine, common in herbicides
used on the farms, was measured in some soil samples in 1981 but was less
than detection levels in 1983. Both 2,3-dichloroaniline and 3,4-dichloro-
aniline were detected in a few samples in the upper 30 cm of soil. These
organic compounds were probably degradation products of the trifluralin
herbicide which was commonly used on the farm. Benzene and chloroform
63
-------
TABLE 14. METALS MASS BALANCE FOR HANCOCK FARM
42.2 cm
As
Ba
Cd
Co
Cr
Cu
Tl
Pb '
Ni
Se
Zn
52.2 cm
As
Ba
Cd
Co
Cr
Cu
Ti
Pb
Nl
Se
Zn
68.9
As
Ba
Cd
Co
Cr
Cu
Tl
Pb
Ni
Se
Zn
Total Mass
Applied
(kg/ ha)
a
0.026
0.165
0.009
0.138
0.032
0.055
0.021
. 0.091
0.06
0.021
0.474
0.32
0.203
0.012
0.026
0.045
0.068
0.026
0.111
• 0.073
0.026
0.585
0.041
0.257
0.012
0.034
0.054
0.087
0.034
0.117
0.073
0.026
0.585
Soil Profile Mass
(kg/ha)
1981
b
108.0
1.79
56.32
317.9
147.1
24.7
64.1
288.89
4.694
152.55
6815 '
1.750
62.26
377.65
140.95
22.62
71.77
184.8
1181.0
122.30
9532.9
1.37
56.37
218.35
143.08
48.09
184.8
1181.0
1983
c
170.4
2.13
91.87
206.3
93.9
22.6
81.3
172.82
6.4
124.30
1284
2.688
93.84
158.14
75.53
12.80
72.41
137.8
957.9
337.83
1566.1
2.65
118.37
200.00
81.29
124.43
137.8
957.9
4 in Profile
(kg/ha)
d = c - b
+62.4
+0.34
+35.55
-111.6
-53.2
-2.1
+ 17.2
-110.07
+I.706
-28.25
-5531
• +0.938
+31.58
-219.51
-65.42
-9.82
+0.64
-47.0
-223.1
+215.53
-7966.8
+1.28
+62
-18.35
-61.79
+76.34
-47.0
-223.1
Unaccounted
Mass
( kg/ha)
e = d - a
+58.8
+0.331
+35.41
-111.6
-53.3
-2.1
+17.1
-110.13
+1.685
-28.57
-5531
+0.926
31.55
-219.55
-65.49
-9.84
+0.53
-47.
-224
+215.49
-7967.1
+ 1,27
+62
-18.40
-61.88
+76.22
-47.
-224
Percent Error
e
(b + a)
54
18
63
35
36
8
27
38
36
19
81
53
51
58
86
43
0.7
' 25
19
176
84
92
110
8
43
158
25
19
Mass Balance Computed on 91 cm of Soil
64
-------
within the profile in 1981 and 1983 was most likely used as a solvent for
herbicides sprayed on the land. Another solvent, tetrachloroethylene and
carbon tetrachloride, was measured above detection limits in 1983. Organic
compounds used as insecticides (i.e., acenaphthylene, m-dichlorobenzene,
p-dichlorobenzene, and p-dichlorobenzene) were also isolated in the upper
30 cm of soil in 1981. The mass of each organic in the irrigation stream
contributed very little to the mass detected in the soil profile.
Bacteriological Data—Irrigation with effluent apparently did increase
the concentration of coliform bacteria in the -upper 30 to 61 cm of the soil
profile. Similarly, fecal streptococcus was detected in the upper 91 cm at
levels greater than analytical limits in 1983 in soils collected from areas
receiving 52.2 cm and 68.9 cm of treated sewage per year. Due to the fre-
quency of isolation of fecal coliform above detection limits in samples
from the irrigation wastewater and soil, fecal coliform appears to have a
higher die-off rate than fecal streptococcus.
Average actinomycetes levels within the soil profile ranged from 10^
to 10^2 counts per gram of soil. During the irrigation period, actinomyce-
tes within the upper 91 cm experienced a one-to-two log increase in concen-
tration. Since an increase in actinomycetes normally follows increased
bacterial and mold growth, the rise in actinomycetes indicated a general
increase in biological activity in the upper 91 cm.
Crops—
In 1982 the Hancock farm was planted in three crops: sunflowers, soy-
beans, and grain sorghum. For late planted crops, sunflower yields were in
the normal range recorded for the High Plains, 1,124 to 2,247 kg/ha (1,000
to 2,000 Ibs/ac). Soybean production ranged from 2,036 kg/ha (30.2 bu/ac)
under Pivot 19 up to 2,697 kg/ha (40 bu/ac) on Pivot 2 which was within the
High Plains soybean range of 1,685 to 2,697 kg/ha (25 to 40 bu/ac) cited by
Texas A & M Extension Service. Grain sorghum yields were less than ex-
pected and ranged from 3,307 kg/ha (2,943 Ib/ac) beneath Pivot 9 to 6,691
kg/ha (5,944 Ib/ac) under Pivot 19.
The 1980, 1981 and 1983 cotton yields obtained from the Hancock farm
65
-------
are presented in Table 15. A definite improvement in crop production was
experienced in .1983. Regardless of irrigation, an increase in production
was anticipated since 1'983 was the only year during the study when a nat-
ural disaster did not affect crop planting and establishment. In general,
cotton production in 1983 exceeded average yields obtained from irrigated
land in Lubbock County.
The overall decrease of nitrogen and phosphorus in tissues from 1981
to 1983 was partially due to the failure of the irrigation stream to meet
crop nutrient requirements. Originally, irrigation was expected to provide
sufficient nitrogen and phosphorus to satisfy crop needs; however, due to
odor problems the effluent was transported through the reservoirs before
application to the soil. Nitrogen concentrations in the irrigation water
were reduced from 42 mg/1 to approximately 12 mg/1 by passing the effluent
through the reservoirs. The nitrogen reduction, in conjunction with a 50
percent reduction in the total hydraulic loading resulted in a nitrogen
deficiency in many of the fields. In addition, no accumulation of trace
metals appeared to have resulted from land application of the City of Lub-
bock's wastewater (Table 16).
Economics—
In the Lubbock land treatment situation, the Hancock farm was private-
ly owned utilizing tenant farmers. The farm owner could not make land pay-
ment by $41,265 in 1980, $16,959 in 19"81, and $45,063 in 1982; but gained
$84,171 in 1983. Therefore, the landowner has experienced a four year net
loss of $19,116. In addition, the tenant farmers as a group netted $30,584
in 1980, $65,564 in 1981, and $202,364 in 1983; but lost $15,584 in 1982.
The farmer's operational cost did not include living expenses for the farm-
ers. The average farmers net income during 1980 through 1983 was
$70,715/yr. If each of nine tenants received an equal share of the profit
then each tenant would have received an average net income of $7,857/yr for
their families to live on.
A comparison of the shift in tenant farmers income between pre- and
post- irrigation periods is given in Table 17. The table shows in general
that the years the farmers had irrigation water (1982 and 1983) they made
66
-------
TABLE 15. COTTON YIELDS, HANCOCK FARM
ON
-vj
Tenant Ha.
Farmer A 56.7
Farmer B 87.8
Farmer C 120.2
Farmer E 171.2
Farmer F 100.8
Farmer G 82.2
Farmer H 116.1
Farmer I 87.4
Lubbock County***
Lubbock County***
1980*
Ac. kg/ha
140
217
297
423
249
203
287
216
70
137
234
100
85
417
393
109
156*
Ib/ac
62
122
208
89
76
371
350
97
Ha.
56.7
143.3
172.0
213.7
100.8
.82.2
116.1
87.4
1981*
Ac . kg/ha
140
354
425
528
249
203
287
216
222
118
178
131
274
316
196
246
373*
Ib/ac
198
105
158
117
244
281
174
219
Ha.
56.7
142.5
65.6
207.2
50.6
82.2
116.1
29.9
1983*
Ac . kg/ha .
140
352
162
512
125
203
287
74
615
579
676
560
740 .
572
353
i
597
(312)*
395**
Ib/ac
547
515
602
498
659
509
314
531
* Dryland
** Irrigated Land
*** Texas A & M Extension Service, Lubbock, Texas
-------
TABLE 16. ELEMENTAL SHIFTS IN COTTON TISSUES OBTAINED FROM HANCOCK FARM
1981 vs. 1983
Concentration
1981 > 1982
Concentration
1981 1983
Concentrations
1981 < 1983
TKN Stalk
TP Stalk
Ca Stalk
Ca Seed
K Stalk
Na Stalk
Na Seed
Cd Stalk
Cd Seed
Cu Stalk
Cu Stalk
Pb Stalk
TKN Seed
TP Seed
K Seed
Fe Stalk
Fe Seed
Ba Seed
Cr Stalk
Cu Seed*
Cu Seed**
Pb Seed
* Overall the same but one or two sharp rises or drops show inconsist-
ency in trend
** Pivots 3 and 11 show substantial drops but overall trend is same or a
little increase
TABLE 17. COMPARISONS OF SHIFT IN FARMERS'
PRE-EFFLUENT TO POST-EFFLUENT
INCOME
1980 + 1981
Net Average
$Income/acre
*$/acre x 2.17 = $/hectare
1982 + 1983
Net Average
$Income/acre*
Pre to Post
Irrigation
$Net acre/yr*
Farmer A
Farmer B
Farmer C
Farmer D
Farmer E
Farmer F
Farmer G
Farmer H
Farmer I
-5.22
+2.82
-0.59
-9.83
-0.96
-9.01
+15.72
+42.30
+25.58
+66.58
+56.57
+ 0.32
+21.40
+105.20
+15.34
-44.79
+89.05
+71.37
+59.39
+ 1.22
___
+22.36
+114.21
+ 9.63
+ 2.49
+63.48
68
-------
more net income per hectare than the baseline period (1980 and 1981) when
there was no effluent water applied. All of the farmers had a positive
four year average net income primarily due to the income received in 1983.
The City of Lubbock paid for all costs associated with the treatment
of the municipal wastewater and transporting the treated sewage to the
Hancock farm. Assuming Lubbock paid 15 percent of the construction costs,
the City's cost per 1000 m3 would have been $98 ($0.37/1000 gal) and $83
($0.31/1000 gal) for 1982 and 1983, respectively.
LUBBOCK INFECTION SURVEILLANCE STUDY (LISS)
The rectangular area within 4.8 kilometers (3 miles) to the north, 4.0
km (2.5 .mi) to the south, and 3.2 km (2 mi) to the east and west of the
perimeter of the spray irrigation rigs on the Hancock farm was designated
as the study area. This area, which includes the small city of Wilson,
Texas and the rural areas north, northwest, and northeast of Wilson, was
divided into six sampling zones (Figure 10). The rectangular Zone 1 in-
cluded all rural households located on the Hancock farm and within 0.5
miles of its perimeter. Zone 2 contained the households located within 0.5
miles of the Hancock site boundary within Wilson. Included in Zone 3 were
all rural residences located from 0.5 to 1.0 (E and W) or 1.5 (N or S)
miles from the Hancock farm. Zone 4 consisted of the Wilson households
which were located 0.5 to 1.0 miles from the site. Zone 5 contained the
rural households which were located from 1.0 or 1.5 to 2 miles (E and W) ,
2.5 miles (S) and 3 miles (N) of the Hancock farm boundary. Zone 5 was
extended to approximately 3 miles .north of the farm due to the prevailing
southerly winds. The households of the small number of Hancock farm work-
ers who resided outside the study area were placed in Zone 6.
The LISS monitored four major periods of wastewater irrigation at the
Hancock farm. These periods were termed spring 1982 (February 16-April
30,1982), summer 1982 (July 21-September 17, 1982), spring 1983 (February
15-April 30, 1983) and summer 1983 (June 29-September 20, 1983). The qual-
ity of the wastewater used for irrigation varied substantially by irriga-
tion period. All of the irrigation wastewater was obtained via pipeline
69
-------
KEY
Rural household participating
during irrigation period(s).
Figure 10. Sampling Zones Comprising the Study Area
70
-------
directly from the Lubbock SeWRP in the spring 1982 irrigation period, since
operation of the reservoirs had not been approved at that time. The qual-
ity of this pipeline effluent was similar to that of a low quality, primary
effluent. Pipeline wastewater comprised 64%, 0?o and 1%, respectively, of
the total applied by spray irrigation in the summer of 1982, spring of
1983, and summer of 1983 irrigation periods. There was some improvement in
the pipeline wastewater quality during summer 1982 and spring 1983, but it
did not reach the quality expected of secondary effluent until summer 1982.
Reservoir wastewater was more consistently of secondary effluent quality in
all three of these periods. This observation is important, since the
majority of irrigation wastewater used during 1982 came via pipeline
directly from the SeWRP, while essentially all the wastewater applied dur-
ing 1983 was from the irrigation reservoirs.
The wastewater utilized at the Hancock farm contained a broad spectrum
of enteric bacteria and viruses. Spray irrigation of wastewater received
via pipeline directly from the Lubbock SeWRP was found to be a substantial
aerosol source of each group of microorganisms monitored in the aerosol
sampling (i.e., fecal coliforms, fecal streptococci, mycob'acteria, Clos-
tridium perfringens, coliphage, and enteroviruses). Microorganism levels
in air downwind of spray rigs using pipeline wastewater were found to be
significantly higher than upwind levels: fecal streptococci levels to at
least 300m downwind, and levels of fecal coliforms, mycobacteria and coli-
phage levels to at least 200 m downwind. The downwind levels were also
significantly higher than the background levels in ambient air outside the
home of participants. Fecal coliform levels were higher than background
levels to beyond 400 m downwind, mycobacteria and coliphage levels to at
least 300 m downwind, and fecal streptococci levels to at least 200 m down-
wind. Operation at night and at high wind speeds appeared to elevate
microorganism levels to greater downwind distances. Enteroviruses were
recovered in the aerosol at 44 to 60 m downwind of irrigation with pipeline
wastewater on each of four virus runs. The geometric mean enterovirus den-
sity in air was 0.05 pfu/m-*, although a much higher density (17 pfu/m-*) was
sampled on one run in August 1982. Spray irrigation of reservoir wastewater
was also found to be a source of aerosolized fecal coliforms, fecal strep-
71
-------
tococci and coliphage, sometimes to downwind distances of at least 125 in.
Since microorganisms densities were much higher in the wastewater from
the pipeline than from the reservoirs, the exposure which most of the study
population received to most microorganisms via the wastewater aerosol was
greater in 1982 than in 1983. The irrigation period in which aerosol ex-
posure at a given distance downwind was estimated to be highest was: sum-
mer 1982 for enterov iruses, summer 1982 for fecal coliforms, and spring
1982 for fecal streptococci. For each of the microorganism groups with
adequate aerosol and wastewater monitoring data, summer 1982 was the irri-
gation period when most of the more highly exposed study population
received either their largest or their second largest cumulative dose from
the wastewater aerosol.
Findings from Self-reported Illness Data
Disease surveillance did not disclose any obvious connection between
illness and degree of wastewater exposure. Self-reports of illness are
always subject to respondent bias. Nevertheless, the participants in the
high exposure level (AEI>5) reported the highest rate of illness shortly
after the onset of wastewater irrigation, both in spring 1982 and in summer
1982. The e*xcess total acute illness among high exposure level partici-
pants over the spring 1982 irrigation period occurred primarily during
February 14-27, 1982, in the initial two weeks of wastewater irrigation.
The high exposure level participants also reported a significant excess of
total acute illness in August 1982, primarily during August 15-28 (after
more than three weeks of wastewater irrigation had elapsed). The high
exposure level participants did not report a comparable excess of acute
illnesses during either irrigation period in 1983. This pattern of excess
illness during both irrigation periods in 1982 is consistent with the
hypothesis of an association of illness with exposure to wastewater irri-
gation: the pattern appeared both upon initial wastewater exposure and in
the summer 1982 irrigation period which produced highest exposure to micro-
organisms in the wastewater aerosol. However, the patterns did not persist
throughout either irrigation period in 1982. In addition, the effects of
known risk factors such as age and social economic status have not been
72
-------
taken into account. A small excess rate of illnesses might have been
associated with the initial and heaviest periods of microorganism emission
from wastewater irrigation. Since the agents which the LISS monitored
clinically and serologically show a very high proportion of asymptomatic
infection, it is difficult to correlate the findings for self-reported
illness with those for the clinically and serologically detected infec-
tions.
Findings from Seroconversion Incidence Densities
An overview of the association of serologically detected infections
with exposure to wastewater aerosols was obtained by comparison of the
seroconversion incidence densities for serum donors in the three levels (or
two groups) of aerosol exposure, for both the entire baseline (June 1980-
Oanuary 1982) and the entire irrigation (January 1982-October 1983) periods
of observations. The high exposure level participants had a higher inci-
dence density of coxsackievirus B4 infections versus intermediate level
participants during the entire irrigation period. In contrast, partici-
pants in the high exposure level had no elevated infection incidence dens-
ity to specific agents in the baseline period. Based on test-based 95%
confidence intervals for the crude incidence density ratios, the high
exposure group (AEIX5) had a significantly greater incidence of infections
to coxsackievirus 82 and echovirus 11 over the irrigation period, but a
significantly greater infection incidence only to one agent, echovirus .9,
during the baseline period.
During the baseline period, individuals in the high exposure level had
the lowest infection incidence densities of the three exposure levels to
all of the adenoviruses tested, to all coxsackie B viruses tested, and to
all echoviruses tested. In the irrigation period, individuals in the high
exposure level had the highest incidence densities of infection by all
coxsackie B viruses tested and by all echoviruses tested. Moreover, in the
irrigation period the high exposure level'also had the highest incidence
density of infections to all of the tested viruses which had been recovered
from the irrigation wastewater. These crude incidence densities suggest a
probable association between seroconversions (especially to viruses
73
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recovered from the wastewater) and wastewater aerosol exposure. The crude
incidence density ratios of the high exposure level to.the intermediate and
low exposure levels during the irrigation period were 1.8 and 1.5, respec-
tively, for the viruses recovered from the wastewater, indicating some
excess risk of viral infection from wastewater aerosol exposure.
Evidence of Association of Specific Infection Episodes with Wastewater
Aerosol Exposure
Specific infection episodes which displayed good or marginal evidence
of association with wastewater aerosol exposure were identified by compar-
ison of results from four methods of investigation; i.e., confirmatory
statistical analysis, exploratory logistic regression (ELR) analysis, con-
fidence intervals of incidence density ratios, and risk ratio scoring.
Some excess risk of viral infection was associated with wastewater
aerosol exposure, based on comparison of'crude seroconversion incidence
densities by aerosol exposure level and by irrigation vs. baseline period.
A symmetric risk ratio score approach provided evidence of a stable and
dose-related association between infection events -and wastewater aerosol
exposure in the infection episodes observed by the LISS. Furthermore, some
infection episodes appear to have been re-lated to wastewater aerosol
exposure, because more statistically significant associations than expected
were found in the confirmatory analysis of independent infection episodes
using a one-sided Fisher's exact test. An exploratory logistic regression
analysis found significant (p<0.05) associations between presence of infec-
tion and degree of aerosol exposure while controlling for the effects of
extraneous variables in four infection episodes.
Additional evidence was considered regarding recovery of the infectious
agent from the irrigation wastewater, seasonal correspondence of the infec-
tion response to aerosol dose, association with contaminated drinking
water, alternative risk factors identified by ELR, and within-household
transmission of infections. The eight, infection episodes with good or mar-
ginal evidence of wastewater aerosol exposure association were placed in
three categories based on the likelihood of causal association of the
infection events with wastewater aerosol exposure:
74
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1) More plausible alternative explanation identified:
o Episode of Klebsiella infections in summer 1983
—alternative: eating food prepared at local restaurant A
o Spurious control episode of echovirus 9 seroconversions
in the baseline period
—alternative: within-household spread
2) Both aerosol exposure and identified alternative explanation(s)
are plausible risk factors (evidence inconclusive):
o Episode of clinical viral isolates excluding adenoviruses
and immunization-associated polioviruses in summer 1982
—alternative: eating food prepared at local restaurant A
o Episode of echovirus 11 seroconversions in 1982
—alternatives: o contaminated drinking water
o Caucasian, large household
o Episode of seroconversions to viruses isolated from waste-
water in summer 1982
—alternatives: o contaminated drinking water
o low income, Caucasian
o Episode of seroconversions to viruses isolated from waste-
water in 1982
—alternative: farmer, history of pneumonia
o Episode of seroconversions in summer 1982 to all serum
neutralization-tested viruses
—alternative: contaminated drinking water
3) Strong evidence of aerosol exposure association and no alterna-
tive explanation identified:
o Episode of poliovirus 1 seroconversions in spring 1982
All five of the infection episodes in Category 2 relate primarily to
echo or coxsackie B viral infections observed in summer 1982 and to agents
recovered from the wastewater at that time. Hence, it is reasonable to
consider these to be five manifestations of a single nonpolio enterovirus
episode centered on the summer 1982 irrigation season. With the heavy rain-
fall, widespread drinking water contamination and other unusual circum-
75
-------
stances which occurred during this summer, it is not surprising that frag-
mentary evidence of various alternative explanations surfaced for this non-
polio enterovirus episode.
All the evidence, however, supports the finding that the episode of
poliovirus 1 seroconversions in spring 1982 was associated with wastewater
aerosol exposure. The results indicate that a general association between
exposure to irrigation wastewater and new infections existed for 1982.
However, even during 1982, the strength of association remained weak and
frequently was not stable. Wastewater, directly from the pipeline, com-
prised much of the irrigation water in 1982. The isolation of entero-
viruses from pipeline wastewater was greater than that observed with the
wastewater that had been retained in reservoirs. The methods employed
resulted in the observation of a large number of infection episodes, none
of which resulted in serious illness. The voluntary nature of participa-
tion and the unrepresentative circumstances of the study area make general-
ization of the results unwise. A larger sample size with greater compar-
ability of the exposure groups on the basis of drinking water sources and
frequency of visiting the same eating establishments would have reduced
their confounding effects.
From the public health standpoint, the lack of a strong, stable asso-
ciation of clinical illness episodes with the level of exposure to irriga-
tion wastewater indicates that wastewater spray irrigation produced no
obvious disease during the study period. However, when more sensitive
indicators of infection were used, a general association was found to
exist, especially for 1982. A particular concern is that statistical
interpretation of the data indicates that the poliovirus 1 seroconversions
were probably related to wastewater aerosol exposure during the spring of
1982, even when the effects of polio immunization were controlled. Because
of the low prevalence of poliovirus antibody observed during the baseline
period, the study population was immunized, and thus was. probably better
protected against polio than other rural populations.
76
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PERCOLATE INVESTIGATION IN THE ROOT ZONE (PIRZ)
Percolate Quantity
During the PIRZ study several problems such as flooding of service
manholes, improper vacuum system performance, inflexibility in irrigation
schedule, etc., limited the amount of percolate quantity and quality data
obtained from the root zone investigation. Therefore the objectives of the
PIRZ study were not achieved. The percentages of the design irrigation
application rates that were actually applied in 1982 to bermuda, cotton and
grain sorghum were 27 percent (99 cm), 114.6 percent (57 cm) and 98.2 per-
cent (99 cm), respectively, at the Hancock site; and 26.1 percent (97 cm),
83.5 percent (38 cm) and 60.7 percent (48 cm) at the Gray site. Only 25 of
the 41 lysimeters on the Gray site contributed percolate during the five
months of the 1982 growing season. At the Hancock site, 26 of the 46 units
had contributed percolate by the end of September.
With increased amounts of irrigation in August and September and with
decreased evapotranspiration requirements due to crop maturity during the
latter part of the growth period, percolate flow increased in lysimeters on
the crop plots. The increase of moisture in the soil profile during the
fall of 1982 led to decreased air leakage in the vacuum systems at all man-
holes and reduced daily vacuum pump operations. In late November and dur-
ing December, the number of lysimeters contributing percolate began to in-
crease at both sites. Fall irrigation, fall precipitation, and decreased
evapotranspiration improved soil moisture conditions in the profile and
subsequently led to percolate generation. During the 1983 growing season,
the percentages of the design application rates actually applied to the
plots for the bermuda, cotton and grain sorghum at the Hancock site were
44.8 (164 cm), 17.5 (9 cm) and 18.4 (19 cm) percent, respectively. At the
Gray site, the respective rates were 15.7 (55 cm), 46.6 (21 cm) and 24.4
(19 cm) percent of design loadings for bermuda, cotton and grain sorghum.
Failure to apply the design hydraulic loading had a major impact on perco-
late collection amounts during the 1983 season. The amounts of percolate
captured by the lysimeters at the Hancock and Gray sites during the study
period are presented in Tables C.3 and C.4. In September 1983 the bermuda
77
-------
and cotton test plots were flood irrigated with approximately 40 cm of
water. The tray lysimeters on the bermuda plot at the Hancock site were
kept operative until November 16, 1983. Percolate was collected from the
three trays at the 61 cm depth and two trays at the 183 cm depth. The
depths of percolate collected by these trays in' November were:
Tray Depth in mm
108 <1
102 4.6
103 . 5.3
108 4.2
109 19.4
Tray 109 had contributed percolate in only one previous event over the
project period. If the water had been in the profile, there was a possi-
bility that more lysimeters would have contributed during the study
period.
Percolate Quality
Many of the water quality samples were of such small volume that only
a few parameters could be measured. Comparison of the geometric means of
parameter concentrations generally revealed a decrease in nutrient levels
in the percolate samples. Levels of total Kjeldahl nitrogen, ammonia
nitrogen, total phosphorus, orthophosphate phosphorus, and organic phos-
phorus decreased by a factor of 10 or greater. The levels of nitrite plus
nitrate-nitrogen (N02+N03) increased in the percolate. Most of this
nitrogen was assumed to be in the form of nitrates. The increase in con-
centration of nitrate resulted from the oxidation of the other nitrogen
compounds present in the applied wastewater as well as from the mobiliza-
tion by the percolate of nitrates stored in the profile.
Examination of sample data sequentially taken over the project period
showed a general decrease in the concentrations of the chemical constitu-
ents recorded as the total volume of percolate collected by the unit in-
creased. This was easily noticeable in sample values obtained over time for
TDS, N03 (Figure 11), NH3, TP, and PO^. Decreases in conductivity, Cl, and
78
-------
I
340
320
300
280
260
240
160
120
100
300
—o
200 .
100 •
_JU
JL
AUG
1ST
.SEPTEMBER
OCTOBER
NOVEMBER
DECEMBER
Figure 11. Variation of Nitrate Concentration in Percolate and Accumulated Weight of
Leached Nitrate in kg/ha with Time for Tube 123 from July through December
1982
-------
504 also occurred during the monitoring period.
Soils
Nitrogen and Phosphorus—
As observed in the Demonstration/Hydrogeologic Study, organic nitrogen
was the primary nitrogen form in the soil profile. The increase in soil
moisture at the Hancock test site resulting from irrigation created favor-
able conditions for the mineralization of organic nitrogen and consequently
a decrease in organic nitrogen. At the Gray site, the average TKN of the
three plots at the 90 cm depth for each sampling period showed little
change.
Nitrate-nitrogen was the major inorganic nitrogen form present in the
soils at both test sites. The nitrate content in the soil profiles at the
Hancock site were generally higher at both the start and end of the project
than the levels measured at the Gray test site. The higher initial nitrate
levels at the Hancock test site probably resulted from the drier soil con-
ditions which historically have been experienced at this site. The drier
soils will retain water-soluble nitrogen forms until excess soil water is
available to leach them from the profile. The average profile nitrate con-
tent for the three sampling periods in the top 90 cm showed a general
decrease over time. High concentrations of nitrates were found in the
initial percolate volumes intercepted by many lysimeter units.
Average orthophosphate phosphorus values in the profile decreased over
the project period in the upper 90 cm depth at both sites. The addition of
this nutrient in the irrigation water would have offset some of the losses
caused by vegetative growth. The total phosphorus consumed by the crops
was less than the amount applied in the irrigation water; therefore, a
portion of the orthophosphate was transformed to more insoluble compounds.
Priority Organics Pollutants—
The composition of the project soils at the beginning and end of the
project period showed reductions in most of the priority organics measured
at both sites. Increases had occurred in the concentration of nine com-
pounds: carbon tetrachloride, dibutylphthalate, hexadecane, methylhepta-
decanoate, methylhexadeconate, octadecane, phenol, propazine, and tetra-
80
-------
chlorethylene. The greatest increase in the soil profile occurred in the
levels of carbon tetrachloride, hexadecane, and dibutylphthalate. The two
former compounds are solvents. The wastewaters pumped to the Hancock site
during the project period contained an average concentration of 4.7 pg/1
for carbon tetrachloride (0.145 kg/ha); <2.0 yg/1 for hexadecane (0.05
kg/ha); and 104 ug/1 for dibutylphthalate (2.6 kg/ha). In water going to
the Gray site the values were 3.2 ug/1 for carbon tetrachloride (0.066
kg/ha) and 140 pg/l for dibutylphthalate (1.98 kg/ha).
Bromide—
Sodium bromide was applied to the surface of the sub-plots annually in
order to trace the movement of percolate through the soil profile. In
1982, the bromide moved about 1.5 cm down through the profile for each
centimeter of water applied at this site. Variability in movement was much
greater" at the Gray site. The bermuda sub-plot, with a much larger
hydraulic loading, showed a bromide ion accumulation in the 60 and 90 cm
level which corresponded to the depth of the indurated caliche layer. The
movement of bromide on the other two plots was approximately 1 .95 cm per
centimeter of applied water.
In the fall of 1983, the cotton and grain sorghum sub-plots still had
bromide present in the surface layer. Some translocations were evident in
the bermuda plots because of the heavier hydraulic loading on these plots.
At the Gray test site, the effect of the caliche layer on the bromide was
evidenced by build-up of bromide in the 45 to 60 cm layer on the bermuda
plots.
AGRICULTURAL RESEARCH STUDIES
Hydraulic Loading Study
Crops—
Crop yield data indicated grain sorghum yields increased as treated
wastewater hydraulic loading increased to approximately 3 m.ha/ha.yr.
Average cotton lint yields obtained from test plots irrigated with 122
cm.ha/ha.yr to 297 cm.ha/ha.yr ranged from 1,300 to 1,538 kg/ha. Cotton
test plots having less than 122 cm.ha/ha.yr of treated sewage applied pro-
81
-------
duced an average lint yield of 100 to 925 kg/ha. In general alfalfa irri-
gated with 365 and 434 cm.ha/ha.yr of treated sewage generated the highest
yields during each cropping period. Furthermore, the alfalfa production
was greatest during the month of June. Common bermuda grass production in
test plots receiving treated sewage was greater than dryland plots. During
June and September 1983, the highest bermuda yield (9368. -+2327. kg/ha)
was harvested from the lowest annual effluent hydraulic loading of 152 cm.
Chemical analysis of the bermuda plant tissue indicated that the crop
had several macro and micro nutrient deficiencies. With the shallow root
system of bermuda increased irrigation may have leached nitrogen past the
root zone; thereby, limiting nitrogen availability to the crop. Other
nutrients such as phosphorus, zinc, potassium and iron appeared to be
deficient in the bermuda tissue.
• Grain sorghum and cotton tissue experienced less nitrogen content in
1983 compared to 1982. Protein content in alfalfa ranged from 24 to 28
percent. Alfalfa irrigated with 137 cm.ha/ha.yr or greater contained more
than 26 percent protein. Phosphorus and potassium, however, may have been
deficient in the alfalfa tissue.
Soils —
Soil texture within the upper 30 cm (1 ft) of the soil profile were
generally sandy clay loam. Clay to clay loams dominated the soils from a
depth of 30 cm to 122 cm (4 ft) within the profile. The majority of soils
from 122 cm to 183 cm (6 ft) were clays. Cation exchange capacities (CEC)
within the test plots were greater than 20 meq/100 g (average 23.6 meq/100 g
+3.3) which were characteristic of the clay/clay loam soils.
Nitrogen--As observed throughout the Hancock farm, organic nitrogen
was the primary nitrogen from within the soil profile. In general, nitrate
nitrogen was the major form of inorganic nitrogen. Leaching of inorganic
nitrogen past a soil depth of 91 cm appeared to have occurred as annual
hydraulic loadings of 61 cm or greater within the cotton test plots (Figure
12). Nitrogen mass balances indicated that nitrates were leached beyond
183 cm of soil in cotton, grain sorghum and bermuda test plots irrigated
with 122 cm.ha/ha.yr or greater.
82
-------
en
*<0
^c
5
o
V.
*»
IS
eO
'c
2k
2*
o
c
300
2OO ~
100
—
100
200
0 cm 20 cm 41 cm 51 cm 61 cm
i i i I i I || i
»
IB :
1
IS, -
* IB! ^
*
1
ISl1
( i^i
. •' •• ••
i.
s *
Si ;
is! 1
•• i1
i" •• • i- =i
i §l
! i
•
••
••••• N Root Zone Pre- irrigation 1983
^KfSt N From Organic N in Root Zone
— — — N Applied in Effluent
69 cm
I I
#
a *
I
i
iB: 1
if
-i
ii
i
86 cm 102 cm
( I I I
*
* *
s- * «' *
I 1
I i !
n n
i1. !i
"l 1
1 1
122
I
i
i
1
ill
cm
1
*
*.
*
*
*
*
*
J
•r
•1
1
1
1
1
Hydraulic
Loading
300
**
ii N Removed by Crop
•i N Removed by Denitrification
• N Measured in Profile Post-irrigation 1983
# N Difference between Measured and Predicted
Figure 12. Nitrogen Mass Balance for Trial 14000 Cotton Plots
-------
All nitrogen mass applied to the alfalfa plots, however, was consumed
and nitrogen fixation was a source of inorganic nitrogen for the crop (Fig-
ure 13). Nitrite plus nitrate-nitrogen (N02+NQ-3) lenses were measured
beneath the entire research area. Nn2+NQ-3 levels decreased with depth as
hydraulic loadings increased. Inorganic nitrogen apparently was not leach-
ed beyond depth of 183 cm.
Minerals--Accumulations of total dissolved solids (IDS) were limited
through leaching of IDS through the soil profile in test plots irrigated
with 122 cm.ha/ha.yr or more. In the grain sorghum plots the exchangeable
sodium percentage (ESP) was less than seven in the top 30 cm of soil. As
the annual hydraulic and salt mass loading increased in the cotton plots
(122 cm.ha/ha.yr to 297 cm.ha/ha.yr) and alfalfa test plots (137
cm.ha/ha.yr to 434 cm.ha/ha.yr) the ESP values within the top 30 cm of soil
increased. In the fall of 1983, the ESP values within the top 30 cm of soil
collected from cotton test plots irrigated with 183 cm and 297 cm/yr were
9.2 and 8.1, respectively. ESP levels were less than 10 within the upper
61 cm of soil. Sodic conditions may have existed within the upper 30 cm of
the plots irrigated with 434 cm/yr. High water consumption of alfalfa
caused accumulations of sodium within 1.8 m of the soil profile at sched-
uled hydraulic loadings of 137, .198, and 259 cm/yr.
Hydraulic Application Frequency Study
Crops—
Yield data (Figure 14) indicated soybean production was highest with
more frequent wastewater application (i.e., one irrigation/week and one
irrigation/2 weeks); whereas, grain sorghum yields were significantly high-
er with longer periods between irrigation (1 irrigation/4 weeks and 1 irri-
gation/8 weeks)(Figure 15). Soil moisture within the profile corresponded
to the type of root system. Less soil moisture was measured beneath the
grain sorghum at soil depths of 122, 152, and 183 cm. These soil moisture
differences possibly were due to: (1) the more extensive grain sorghum
root system and (2) the fact that growing season for soybeans ends with a
complete shutdown of the plant while the milo plants stay green and con-
tinue to extract moisture from the soil until frost kills the crop.
84
-------
CD
800
600
I 400
o>
^ 200
O> -|-
V,
1 20°
| 400
600
800
Effluent Water
I
137 198 259 3O5 365 43'
1
t
t
t
t
1
1 1
1 1
I 1
1 1
1 1
! i i
i !
• '•
i ' •
iiii!
: : : ! !
*• s : i i Si
Si Si i V 5 8
IS1 B ' ^ ' fi ' 5' 8 '
iSi . l^i. . iS: • !0: I iM . .Si
i! ii! iii :* JU
•* ii i ! !«
i • i 1 1
: i
Well Water
| 1 1
4 0 365 3O5 259 cm/
• i5 • .B! • i5l • .Si 1
"•"!?"" |l • | w I T — —••*•- • i If
i i i i I i
i t jt •*
m I
i ;
i
*•••• N Root ^one Pre- irr iijyt inn 19BJ
^fftfQI N From Organic N id Knot Zone
•••————— N ADD 1 i eel in Ef t'l ijtnt.
^ • •• • M Removed by Crop
• •• •• N Keinuveci hy Dertitr i f'icat ion
IHH^ N t-Vj;isure<1 in Prof i l« Post- i rr itjat ion 1985
* # '* N Dtflurenct: between Mcauured and Predicted
Figure 13. Nitrogen Mass Balance for Trial 16000 Alfalfa plots
-------
a
UJ<
'S
"
O
Application Frequency
D1 Application/wk
O1 Application/2 wks
A 1 Application/4 wks
-f- 1 Application/8 wks
0.00
20.00
UO.OO
60.00 80.00 100.00
HTDRflULJC LORDING -(CM)
120.00-
1110.00
160.00
Figure 14. Soybean Seed Yield vs Hydraulic Loading - Trial 170GO
"og
"8-I
— o
a -
Application Frequency
D - 1 Application/wk
O - 1 Application/2 wks
A - 1 Application/4 wks
+ - T Application/B wks
0.00
20.00
UO.OO
I 1 I
60.00 60.00 100.00
HYORflULJC LOflDING (CM)
120.00
mo. oo 160.00
Figure 15. Milo Whole Plant Yield vs Hydraulic Loading - Trial 17000
86
-------
At an annual hydraulic loading of 30 cm/yr, symbiotic nitrogen fix-
ation apparently provided inorganic nitrogen to the soybeans. Once the
hydraulic loading was increased to 61 cm/yr, sufficient nitrogen mass was
applied to soybeans to inhibit nitrogen fixation. In the soybean test
plots inorganic nitrogen leached through the 183 cm soil profile when 122
cm of effluent/yr was applied at irrigation intervals greater than once per
week. Similarly, nitrogen was leached from the 91 cm profile within the
grain sorghum test plot irrigated with 122 cm/yr.
Sodium increased in the grain sorghum at low irrigation rates. Leach-
ing of Na within the plots resulted when greater quantities of water were
applied per irrigation period. Consequently, less Na was available for the
crop. Grain sorghum, with a deeper more extensive root system, was not
affected by minor changes in loadings or frequencies of application, while
a small shift of either of these factors on the soybean crop changed the
availability of sodium.
Soil —
The ability of the crop to adapt to water stress conditions was a fac-
tor which influenced Na accumulation within the soil profile. Due to the
shorter growing season in 1982, soybeans with a more shallow root system
and possibly greater water requirements than sorghum, utilized water within
the upper 61 cm of soil. Consequently, the greatest Na levels as a percent
of base saturation was observed in the upper 61 cm of the soil. In addi-
tion, higher water application frequency appeared to increase ESP values in
the upper soil profile.
Water utilized by grain sorghum caused an accumulation of Na at great-
er soil depths than soybeans. Upward migration of water due to capillary
action during water stress periods (increased time intervals between irri-
gation) may have caused an increase in Na in the upper profile.
87
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REFERENCES
1. Camann, D. et al. Health Effects Study for the Lubbock Land Treat-
ment: Lubbock Infection Surveillance Study. Vol. IV of the Lubbock
Land Treatment System Research and Demonstration Project. EPA. U.S.
EPA Health Effects Research Laboratory, Cincinnati, Ohio, 1985.
2. Chang, A. C. and A. L. Page.' Toxic Chemicals Associated with Land
Treatment of Wastewater. International Symposium, State of Knowledge
in Cold Regions Research and Engineering Laboratory, Hanover, New
Hampshire, 1978. pp. 47-57.
3. EPA. Process Design Manual for Land Treatment of Municipal Waste-
water. EPA 625/1-81-013, U.S. EPA Center for Environmental Research
Information, Cincinnati, Ohio, 1981.
4. George, D. B., N. A. Klein, and D. B. Leftwich. Agricultural Research
Studies: Vol. Ill of the Lubbock Land Treatment System Research and
Demonstration Project. EPA. U.S. EPA. Robert S. Kerr Environmental
Research Laboratory. Office of Research and Development, Ada, Okla-
homa, 1985.
5. George, D. B. et al. Demonstration/Hydrogeologic Study: Vol. I of
the Lubbock Land Treatment System Research and Demonstration Project.
EPA. U.S. EPA, Robert S. Kerr Environmental Research Laboratory,
Office of Research and Development, Ada, Oklahoma, 1985.
6. Loehr, R. C., W. 0. Jewell, G. D. Novak, W. W. Clarkson, G. S. Fried-
man. Land Application of Wastes. Vols. 1 and 2. ' Van Nostrand Rein-
hold, New York, 1979.
7. Majeti, V. A. and C. S. Clark. Health Risks of Organics in Land
Application. In: Journal of the Environmental Engineering Division,
Proceedings of the American Society of Civil Engineer, ASCE, Vol. 107,
No. EE2, 1981.
8. Overcash, M. R. Land Treatment of Municipal Effluent and Sludge:
Specific Organic Compounds. In: Utilization of Municipal Wastewater
and Sludge on Land. University of California, Riverside, California,
1983. pp. 199-231.
9. Pettygrove, G. S. and T." Asano (ed). Irrigation with Reclaimed Munic-
ipal Wastewater - A Guidance Manual. Report No. 84-1 wr, California
State Water Resources Control Board, Sacramento, California, 1984.
10. Ramsey, R. H. and R. M. Sweazy. Percolate Investigation in the Root
Zone: Vol. II of the Lubbock Land Treatment System Research and Dem-
onstration Project. EPA. U.S. EPA, Robert S. Kerr Environmental
Research Laboratory, Ada, Oklahoma, 1985.
-------
11. Stromberg, L. K. and S. L. Tisdale. "Treating Irrigated Arid- Land
Soils with Acid-Forming Sulphur Compounds". Tech. Report No. 24, The
Sulphur Institute, Washington, D.C., 1979.
12. Wells, D. M, R. M. Sweazy, and G. A. Whetsone. Long Term Experiences
with Effluent Reuse. Journal of the Water Pollution Control Federa-
tion, Vol. 51, No. 51, 1979. pp. 2641-2648.
13. Williams, R. B. 1982. Wastewater Reuse - An Assessment of the Poten-
tial and Technology. Water Reuse. Edited by E. 3. Middlebrooks. Ann
Arbor Science Publ., Inc., Ann Arbor, Michigan, pp. 87-136.
89
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APPENDIX A
Demonstration/Hydrogeologic Study
Agricultural Cropping Patterns
i.
-------
Reservoir
-1-2-1 Playa
Soybeans
+ + + Sun Flowers
Figure A.1. Summer 1982 cropping pattern for Hancock Farm
90
-------
I I COTTON
i&SS MIIO
WHEAT » MILO
f f -r
•fffff. WHEAT « BEANS
I-"-""-' WHEAT » ALFALFA
ROW IRRIGATION
DISTRIBUTION CAN
DISTRIBUTION LINE
HANCOCK LAND
DISPOSAL SITE
Figure A.2. Summer 1983 cropping pattern, Hancock Farm
91
-------
vo
N>
Grazing
::-:>-:: Water
1 cm = O.27 km
Figure A.3. Winter 1982 crop and grazing areas at Gray Farm
-------
WINTER CROP
1982-1983
ALFALFA
1982-1983
Figure A.4. Cropping patterns on Gray Farm during 1982 and 1983
93
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APPENDIX B
Supplemental Figures and Tables
for Section 3 (Project Design)
-------
TABLE B.1. WATER ANALYSIS
Alkalinity, mg/1 CaOIj
Total Organic Carbon (TOC), mg/1
Specific Conductance, umhos/cm
Total Dissolved Solids (TDS), mg/1
pH
Chloride (Cl), mg/1
Total Kjeldahl Nitrogen (TKN), mg N/l
Nitrite plus Nitrate (N0.2+N03), mg N/l
Ammonia (Nh^), mg N/l
Total Phosphorus (TP), mg P/l
Orthophosphate Phosphorus (P04), mg P/l
Organic Phosphorus (Org P), mg P/l
Chemical Oxygen Demand (COD), mg/1
Sulphate (504), mg S04/1
Total Coliform (TO/100 ml
Fecal Coliform (FC)/100 ml
Fecal Streptococci (FS)/100 ml
Salmonella/300 ml
Aluminum (Al), mg/1*
Arsenic (As), mg/1*
Barium (Ba), mg/1*
Boron (B), mg/1*
Calcium (Ca), mg/1*
Cadmium (Cd), mg/1*
Cobalt (Co), mg/1*
Chromium (Cr), mg/1*
Copper (Cu), mg/1*
Iron (Fe), mg/1*
Lead, (Pb), mg/1*
Magnesium (Mg), mg/1*
Nickel (Ni) , mg/1*
Potassium (K), mg/1*
Selenium (Se), mg/1*
Silver (Ag), mg/1*
Sodium (Ag), mg/1*
Thallium (Tl), mg/1*
Zinc (Zn), mg/1*
Anthracene/phenathrene (yg/1)
Atrazine (yg/1)
Benzene (yg/1)
Benzeneacetic acid, (yg/1)
4-t-butylphenol, (yg/1)
Carbontetrachloride, (yg/1)
4-chloroaniline, (yg/1)
Chlorobenzene, (yg/1)
Chloroform, (yg/1)
2-chlorophenol, (yg/1)
1-chlorotetradecane, (yg/1)
Dibutylphthalate, (yg/1)
2,3-dichloroaniline, (yg/1)
3,4-dichloroaniline, (yg/1)
Dichlorobenzene M,P,0, (yg/1)
Dichloromethane, (yg/1)
2,4-dichlorophenol, (yg/1)
Diethylphthalate, (yg/1)
Diisooctylphthalate, (yg/1)
Dioctylphthalate, (yg/1)
Dodecanoic acid, (yg/1)
Ethyl Benzene, (yg/1)
Heptadecane, (yg/1)
(continued)
-------
TABLE B.1, continued
Manganese (Mn), mg/1*
Mercury (Hg), mg/1*
Molybdenum (Mo), mg/1*
Methylhexadecanoate, (yg/1)
1-methylnaphthalene, (yg/1)
2-methylphenol, (y'g/1)
4-methylnaphthalene, (yg/1)
Naphthalene, (yg/1)
Octadecane, (yg/1)
Hexadecane, (yg/1)
Hexadecanoic acid, (yg/1)
Methyheptadecanoate, (yg/1)
Phenol, (yg/1)
Propazine, (yg/1)
ct-terpineol, (yg/1)
Tetrachloroethylene, (yg/1)
Toluene, (yg/1)
Trichloroethylene, (yg/l)
*Total and Dissolved
95
-------
TABLE B.2. SOIL ANALYSIS
Alk, mg/g as
TOC, mg/g
Specific Conductance, pmhos/cm
IDS, mg/g
pH
Cl, mg Cl/g Total
TKN, mg N/g Total
N02+N03, mg N/g
NH3, mg N/g
P, mg P/g
PO^, mg P/g
50^, mg S/g
CaC03, mg/g as CaC03
Cationic Exchange
Anionic Exchange
Organic Matter
Buffer Capacity
Solution Cations, mg/g
Sulfur, mg/g
Specific Gravity
Texture
Bulk Density
Consistency
Color
Humus, mg/g
Total Coliform/g
Fecal Coliform/g
Fecal Strep/g
Actinomycetes/g
Fungi/g
Al, mg/g*
As, mg/g*
Ba, mg/g*
B, mg/g*
Ca, mg/g*
Cd, mg/g*
Co, mg/g*
Cr, mg/g*
Cu, mg/g*
Fe, mg/g*
Pb, mg/g*
Mg, mg/g*
Mn, mg/g*
Hg, mg/g*
Mo, mg/g*
Ni, mg/g*
K, mg/g*
Se, mg/g*
Ag, me/g*
Na, mg/g*
Tl, mg/g*
Zn, mg/g*
Acenaphthylene, (pg/kg)
2-chlorophenol, (pg/kg)
Atrazine, (pg/kg)
Benzene, (pg/kg)
Benzeneatic acid, (pg/kg)
4-t-butylphenol, (pg/kg)
Carbontetrachloride, (pg/kg)
4-chloroaniline, (yg/kg)
Chlorobenzene
Chloroform, (pg/kg)
Anthracene/phenanthrene, (pg/kg)
1-chlorotetradecane, (pg/kg)
Dibutylphthalate, (pg/kg)
2,3-dichlorotetradecane, (pg/kg)
3,4-dichlorotetradecane, (pg/kg)
Dichlorobenzene, ( g/kg) M,P,0 (3)
Dichloromethane, (pg/kg)
2,4-dichlorophenol, (pg/kg)
Diethylphthalate, (pg/kg)
Diisooctylphthalate, (pg/kg)
Dioctylphthalate, (pg/kg)
Oodecanoic acid, (pg/kg)
Ethylbenzene, (pg/kg)
Heptadecane
Hexadecane, (pg/kg)
Hexadecanoic acid, (pg/kg)
Methylheptadecanoate, (pg/kg)
Methylhexadecanoate, (pg/kg)
1-methylnaphthalene (pg/kg)
2-methylphenol, (pg/kg)
4-methylphenol, (pg/kg)
Napthalene, (pg/kg)
4-nonylphenol, (pg/kg)
Octadecane, (pg/kg)
Phenol, (pg/kg)
Propazine, (pg/kg)
a-terpineol, (pg/kg)
Tetrachloroethylene, (pg/kg)
Toluene, (pg/kg)
Trichloroethane, (pg/kg)
Trichloroethylene (pg/kg)
*Total and Available
96
-------
TABLE B.3. CROP ANALYSIS PROTOCOL
COTTON
Lint, Seed, Burs, Stems:
TC, PC, FS
TKN, TP
K, Ca, Mg, Na, Zn, Mn, Fe, B, Al, Cd, As
Seed:
Protein, Cl, Oil
GRAIN SORGHUM (MILD)
Grain, Stalk, Leaf:
TC, FC, FS
TKN, TP, Cl
K, Ca, Mg, Na, Zn, Mn, Fe, B, Al, Cd, As
Stalks, leaf:
HCN, Fiber
Grain:
Protein, Starch, Oil
ALFALFA, BERMUDA
Whole Plant:
TC, FC, FS
TKN, TP, Protein, Cl
K, Ca, Mg, Na, Zn, Mn, Fe, B, Al, Cd,
Fiber
SOYBEANS, SUNFLOWERS
Leaf, Stem, Seed:
TC, FC, FS
TKN, TP, Cl
K, Ca, Mg, Na, Zn, Mn, Fe, B, Al, Cd, As
Seed:
Protein, Oil
WHEAT, DATS
Leaf, Stem, Seed:
TC, FC, FS
TKN, TPS, Protein, Cl
K, Ca, Mg, Na, Zn, Mn, Fe, B, Al, Cd, As
Seed:
Starch
As
97
-------
TABLE. B.4. WATER qUALITY ANALYSIS SCHEDULE FOR PERCOLATE SAMPLES
Group
Parameter Classification
Alkalinity A
COD A
IDS A
Specific Conductance A
pH A
Total Kjeldahl Nitrogen A
NH3 • A
N02 + N03 A
Total Phosphorus A
Organic Phosphorus A
Orthophosphate Phosphorus A
TOC A
Ca B
Cl A
K A
Mg B
Na A
. B
Heavy Metals C
Ag, As, Ba, Cd, Cr, Cu, Fe, Hg, Ni
Pb, Se, Zn, Co, Al, Mn, Tl, Mo, B
Trace Organics D
Fecal Coliform C
Viruses C
Key: A - weekly; B - Monthly; C - Quarterly; D - Yearly
98
-------
MD
•—• Boundary
Road
° Well
: Water
Figure B.1. Gray Farm ground water monitoring locations
-------
DRINKING WATER
O
o
GROUND WATER
10212
A / Road
Location '
Figure B.2. Hancock Farm Ground Water and Drinking Water Monitoring Locations
-------
APPENDIX C
Supplemental Figures and
Tables for Section 4 (Summary of Findings)
-------
TABLE C.1. GROUND WATER QUALITY - GRAY WELLS
Parameter
Alkalinity (mg CaC03/l
Conductivity (umhos/cm)
TDS (mg/1)
pH
Cl (mg/1)
S04 (mg/1)
TKN (mg N/l)
N02 + N03 (mg N/l)
NH3 (mg/1)
TP (mg P/l)
P04 (mg P/l)
Org P (mg P/l)
COD (mg/1)
TOC (mg/1)
TC (Counts/100 ml)
FC (Counts/100 ml)
FS (Counts/100 ml)
Metals, Dissolved (mg/1)
Al
As
Ba
B
Ca
Cd
Co
Cr
Cu
Fe
Pb
Monitoring
June 1980-Jan. 1982
224-402
1 ,244-2,882
1,010-2,271
7.10-7.72
208-680
149-795
0.28-6.97
5.05-35.89
0.02-2.05
0.10-3.49
<0. 01-0. 84 . .
0.08-2.31
27.2-125.4
12.2-38.6
0-300,000,000
0->3603
0-4,501
0.080-3.530
<0. 058-0. 243
0.058-0.243
0.521-3.671
47.7-161.7
<0. 001 -0.004
<0. 005-0. 012
<0. 005-0. 025
<0. 005-0. 106
0.021-0.556
<0. 002-0. 060
Period
Feb. 1982-Dec.1983
140-439
1,098-3,846
723-2,812
7.28-8.13 •
154-686
148-1,067
0.20-7.65
0.77-33.43
<0.01-6.96
<0. 01-1 .94
<0. 01-1. 68
<0. 01-0. 23
11.4-100.3
1.1-9.9
0->31,700
0-30,000
0-26,660
0.153-1.477
<0. 005-0. 038
0.019-0.250
<0. 100-1. 174
44.1-175.1
<0. 001 -0.004
<0. 005-0. 030
<0. 005-0. 023
<0. 005-0. 020
0.021-1.105
0.003-0.041
(continued)
101
-------
Table C.1, continued
Parameter
'Mg
Mn
Hg
Mo
Ni
K
Se
Ag
Na
Tl
Zn
Metals, Total (mg/1)
Al
As .
Ba
B
Ca
Cd
Co
Cr
Cu
Fe
Pb
Mg
Mn
Hg
Mo
Ni
K
Monitoring
June 1980- Jan. 1982
22-138
0.002-0.260
<0. 001 -0.003
<0. 003-0. 055
<1. 005-0. 077
8-40
<0. 005-0. 009
<0.005
73-476
<0. 005-0. 007
0.027-0.591
0.146-36.340
<0. 005-0. 018
0.028-4.750
<0. 100-5. 10
30-394
<0. 001-0. 011
<0. 005-0. 096
0.003-0.096
-------
Table C.1, continued
Parameter
Se
Ag
Na
Tl
Zn
Organics (ppb)
Acenaphthylene
Anthracene
Atrazine
Benzene
4-t-butylphenol
Carbon tetrachloride
4-chloroaniline
Chlorobenzene
Chloroform
2-chlorophenol
1 -chlorotetradecane
Dibutylphathalate
2 ,3-Dichloroaniline
3 ,4-Dichloroaniline
Dichlorobenzene meta
Dichlorobenzene para
Dichlorobenzene ortho
Dichloromethane
2,4-Dichlorophenol
Diethylphthalate
Diisooctylphthalate
Dioctylphthalate
Monitoring
June 1980- Jan. 1982
<0. 005-0. 017
<0. 005-0. 031
93-434
<0. 005-0. 012
0.061-0.923
<5.0
<2.0-2.9
<2.0-5.7
<1.0-11.9
<2.0-3.4
<5.0
<10.0
<1.0-1 .2
<1. 0-8.4
<2.0-3.3
<2.0-5.7
<2. 0-14.1
<5. 0-8.1
<2.0-2.6
<2.0-3.2
<2. 0-2.1
<2.0-4.2
NR
<2.0-4.6
<2.0-11.7
<2. 0-757. 7
<2.0-34.4
Period
Feb. 1982-Dec.1983
<0. 002-0. 013
<0.001
118-573
<0.005
<0. 020-1 .568
<2.0-4.3
<2.0-5.2
4.7-10.0
<1.0-6.2
<1. 0-3.0
2.4-6.5
<10.0
<1.0
<1.0-2.5
<1. 0-3.0
<2.0-4.9
<1. 0-8.8
<2.0-8.9
<2.0-2.6
O.O-1.7
<1.0-1.7
0.0-1.9
NR
<2. 0-3.0
<2 .0-862.1.
<2. 0-475.0
<2.0
(continued)
103
-------
Table C.1, continued
Parameter
Ethyl Benzene
Heptadecane
Hexadecanoic. Acid
Methylheptadecanoate
Methylhexadecanoate
1 -Methylnapthalene
2-Methylphenol
4-Methylphenol
Naphthalene
4-nonylphenol
Octadecane
Phenol
Propazine
o-terpineol
Tetrachloroethylene
Toluene
Trichloroethane
Trichloroethylene
Monitoring Period
June 1980-Jan. 1982 Feb.
<1 .0-2.1
<2. 0-3.0
9.0-111.0
<2. 0-14.1
<2.0-6.9
<2.0-2.9
<2.0-2.7
<5.0-5.2
<2.0-7.5
2.09
(1 data point) (1
<2.0-4.4
<10.0
<2.0-2.3
<2.0-2.3
<1.0-5.4
<1 .0-4.6
<5.0
1.4-4.6
1982-Dec.1983
<1. 0-2.1
<2.0
NR
<2.0-2.3
<2.0
<1.0-1.9
<1.0-1 .9
<2.0=-31.0
<1 .0-4.0
<2.0
data point)
<2. 0-4.0
<1 .0-10.5
<1. 0-2.1
<1. 0-2.1
<1.0-5.3
<1.0-2.2
<5. 0-10.4
0.0-7.2
104
-------
TABLE C.2. RANGE OF AVERAGES WATER QUALITY CONSTITUENTS -
HANCOCK FARM
Parameter
Alkalinity (mg CaC03)
Specific Conductivity (umhos/cm)
TDS (mg/1)
pH
Cl (mg/1)
S04 (mg/l>
Total N (mg N/l)
N02 + N03 (mg N/l)
NH3 (mg N/l)
Total. P .(mg P/l)
Ortho P (mg P/l)
Org P (mg P/l)
COD (mg/1)
TOC (mg/1)
Total Coliform (counts/100 ml)
Fecal Coliform (counts/100 ml)
Fecal Strep (counts/100 ml)
Metals-Dissolved (mg/1)
Al
As
Ba
B
Ca
Cd
Co
Cr
Cu
Monitoring
6/80-1/82
230-349
504-1287
363-989
7.32-7.2
22-246
32-243
0.10-4.21
0.79-10.90
0.03-1.36
0.08-0.58
<1. 01 -0.29
<0. 01-5. 50
6.6-116.7
7.1-53.3
0-200,004,032
'0-150,002,752
0->4,604
0.124-9.180
<0. 005-0. 018
0.042-0.369
0.188-1.186
24-150
<0. 001 -0.004
<0. 005-0. 016
<0. 005-0. 031
<0. 005-0. 090
Period
2/82-12/83
238-382
694-1933
462-1250
7.33-8.14
17-345
44-271
0.11-24.89
0.10-14.99
0.03^15.15
0.02-1.02
<0. 01-0. 85
<0. 01 -0.08
5.8-84.3
0.9-15.4
65-43,275
0-45,005
8-19,200
0.173-4.656
<0. 010-0. 010
0.022-0.236
0.510-2.175
29-118
<0. 001-0. 003
<0. 005-0. 008
<0. 005-0. 008
<0. 005-0. 126
(continued)
105
-------
Table C.2., continued
Parameter
Fe
Mg'
Mn
Mo
Ni
K
Se
Ag
Na
Tl
Metals, Total (mg/1)
Al
As
Ba
B
Ca
Cd
Co
Cr
Cu
Fe
Pb
Mg
Mn
Mo
Ni
K
Se
Ag
Na
Monitoring
6/80-1/82
0.170-4.688
21-70
0.006-0.650
0.004-0.058
<0. 005-0. 162
7-13
<0. 005-0. 011
<0.005
30-148
0.028-0.247
0.114-6.650
<0. 003-0. 020
0.059-0.482
<0. 100-0. 792
29-103
<0. 001-0. 008
. 0.003-0.005
0.002-0.047
0.004-0.112
0.113-3.710
<0. 002-0. 022
37-85
0.003-1.230
0.010-0.085
<0. 005-0. 133
8-15
0.001-0.009
<0.005
78-686
Period
2/82-12/83
0.337-8.885
28-69
0.009-1.642
NR
<0. 005-0. 190
6-17
<0. 005-0. 134
<0. 001-0. 005
34-181
<0. 005-0. 007
0.379-2.850
0.002-0.011
0.059-0.150
NR
20-137
NR
<0.005-
<0.005-
<0. 005-0. 006
0.580-6.410
<0. 002-0. 006
31-55
0.020-0.132
NR
<0.005
11-18
<0. 005-0. 009
<0.001
78-159
(continued)
106
-------
Table C.2., continued
Parameter
Tl
Zn
Qrganics (ppb)
Acenapththylene
Anthracene
Atrazine
Benzene
4-t-Butylphenol
Carbon Tetrachloride
4-Chloroaniline
Chlorobenzene
Chloroform
2-Chlorophenol
1 -Chlorotetradecane
Dibutylphathalate
2 ,3-Dichloroaniline
3 ,4-Dichloroaniline
Dichlorobenzene meta
Dichlorobenzene para
Dichlorobenzene ortho
2,4-Dichlorophenol
Diethylphthalate
Diisooctylphthalate
Dioctylphthalate
Ethylbenzene
Heptadecane
Hexadecane
Hexadecanoic Acid
Methylheptadecanoate
Monitoring
6/80-1/82
0.001-0.009
0.072-0.0436
-
<5.0-5.9
<2.0-4.4
<2.0-38.9
<1.0-2.3
<2.0-75.9
<5. 0-193.0
<10. 0-11.1
<1.0
<1.0-7.4 •
<2.0
<2.0-52.2
<2. 0-111 .0
<5.0-9.2
2.0-7.1
<2. 0-3.9
<2.0-9.6
<2.0-3.6
<2.0-5.8
<2.0-16.7
9.9-223.8
<2.0-62.2
<1.0-2.6
<2.0-3.7
<2.0-2.5
17.6-36.0
<2. 0-36.0
Period
2/82-12/83
<0.005
<0. 020-0. 096
<3.0-3.9
<2.0-7.2
4.7-13.9
<1.0-3.7
1.3-2.5
2.8-5.4
<10.0
<1.0-1.6
<1. 0-12.2
<2.0
<2.0-8.9
2.6-16.4
2.8-8.2
<2.0-8.3
<2.0
<2.0
<2.0
<2.0-5.8
3.0-62.3
<2. 0-378.0
<2.0-2.9
<1.0-1 .8
<2. 0-3.1
<2.0
<1.0
<2.0-3.4
(continued)
107
-------
Table C.2., continued
Parameter
Monitoring Period
6/80-1/82
2/82-12/83
Methylhexadecanoate
1-Methylnaphthalene
2-Methylphenol
4-Methylphenol
Naphthalene
Octadecane
Phenol
Propazine
a-terpineol
Tetrachloroethylene
Toluene
Trichloroethane
Trichloroethylene
<2.0-560.0
<2.0-2.1
<2.6-2.8
<5.0-6.8
<2.0-7.0
<2.0-6.7
<10.0-24.9
<2.0-4.5
<2.0-4.4
O.O-
0.0-12.3
<5.0-11.5
<1.0-8.9
<2.0-4.3
2.0-3.2
<2.0
<5.0
<2.0-3.4
<2.0-6.1
<10.0
5.6-9.8
2.0
<1.0-4.9
<1 .0
<5.0
0.0-5.8
108
-------
TABLE C.3. DEPTH OF PERCOLATE INTERCEPTED BY LYSIMETER UNITS OVER STUDY PERIOD AT THE HANCOCK FARM
Location
Tray
0.61 m
1.22 m
1.83 m
Tube
1.22 m
1.83 m
2.44 m
Controls
1.22 m
1.83 m
Bermuda
Units
101a
102
103
Avg.b
104
105
106
Avg.
107
108
109
Avg.
111
112
Avg.
113
114
Avg.
121
122
Avg.
123
124
Avg.
Depth
(cm)
5.1
12.2
4.4
7.2
0.9
0.9
Neg.
1 .1
0.3
4.1
2.2
0.1
0.1
108.1
43.1
75.6
171.3
155.3
163.3
113.3
114.9
114.1
Grain Sorghum
Units
201
202
203
Avg.
204
204
206
Avg.
207
208
209
Avg.
211 .
212
Avg.
; 213
214
Avg.
215
216
Avg.
Depth
(cm)
0.8
1.7
1.25
0.8
0.8
0.8
0.3
Neg
Neg
0.3
0.5
0.5
Neg
1.4
1.4
Cotton
Units
301
302
303
Avg.
304
304
306
Avg.
307
308
309
Avg.
311
312
Avg.
313
314
Avg.
Depth
(cm)
Neg
3.9
3.9
3.5
3.5
3.2
0.9
1 .6
0.7
2.9
0.8
1.5
10.8
1.2
6.0
2.0
2.0
1.2
f?Unit code — the first digit identifies the plot and the next two identify lysirneter type and depth.
DAverage of producing units.
-------
TABLE C.4. DEPTH OF PERCOLATE INTERCEPTED BY LYSIMETER UNITS OVER STUDY PERIOD AT THE GRAY SITE
Bermuda
Location Units
Tray
0.6 m 101a
102
103
Avg.b
1.22 m 104
105
106
Avg.
1.83 m 107
108
109
Avg.
_» Tube
0 1.22 m 111
112
Avg.
1.83 m 113
114
Avg.
2.44 m 115
116
Avg.
Depth
(cm)
Neg
6.1
6..1
0.3
1.8
0.6
0.9
3.3
4.1
1.5
3.0
31.1
10.8
21.0
10.1
14.1
12.1
28.9
25.1
27.0
Cotton
Units
201
202
203
Avg.
204
205
206
Avg.
207
208
209
Avg.
211
212
Avg.
213
214
Avg.
Depth
(cm)
12.3
3.6
6.6
• 7.5
5.2
0.6
4.3
3.4
2.9
0.2
2.0
1.7
5.8
6.7
6.3
0.4
0.4
0.4
Grain Sorghum
Units
301
' 302
303
Avg.
304
305
306
Avg.
307
308
309
Avg.
311
312
Avg.
313
314
Avg.
Depth
(cm)
17.2
33.2
15.5
22.0
1.7
7.2
4.5
1.3
1.0
4.3
2.2
5.0
18.8
11.9
17.0
33.1
25.1
aUnit code — the first digit identifies the plot and the next two identify lysimetr type and depth.
DAverage of producing units.
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CONTOUR ELEVATIONS IN FEET (.3048 M/ft)
Figure C.1. Water Level Contours, December 1981, Gray Farm
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CONTOUR ELEVATIONS IN FEET
(.3048 METERS/FT)
Figure C.2. Water Level Contours, December 1981, Hancock Site
112
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