&ER& United States Environmental Protection Agency Municipal Environmental Research Laboratory Cincinnati OH 45268 Research and Development EPA-600/S2-82-019 May 1982 Project Summary Spreading Lagooned Sewage Sludge on Farmland: A Case History C. Michael Robson and Lee E. Sommers This report describes a case history on the use of anaerobically digested (stabilized) sewage sludge on agricul- tural land. Although this project involved a single application of sludge to soils, it revealed much about equip- ment, procedures, and regulatory agency requirements. The case history describes the dis- posal of approximately 420,000 m3 (111 million gal) of stabilized sludge and other materials that had been stored in holding lagoons at the Bel- mont, Indiana, Wastewater Treat- ment Plant, which is owned and operated by the Department of Public Works of the Consolidated City of Indianapolis, Indiana. The stabilized sludge and other materials were removed to enable the construction of new wastewater treatment facilities on portions of the Belmont site pre- viously occupied by the sludge lagoons. The major portion of the sludge (265.000 m3) was disposed of by application to privately owned cro- pland in adjacent Boone County, Indiana. Cadmium (Cd) and polychlorinated biphenyl (PCB) contents of the sludge were the major constraints in deter- mining the sludge application rates to the cropland. Frequent analyses of the sludge solids were needed to identify the appropriate rates. Landowners consigned about 5,000 ha (13,000 acres) for a single sludge application, after which corn and soybeans were grown. An effective public relations program minimized public resistance and secured the cooperation of area residents. Analyses revealed no measurable increases in the Cd and PCB contents of the grain after the single sludge application. Techniques were devel- oped for removing, transporting, and applying lagooned sludges and for administering and monitoring such a program. This Project Summary was devel- oped by EPA's Municipal 'Environ- mental Research Laboratory, Cincinnati, OH. to announce key find- ings of the research project that is fully documented in a separate report of the same title (see Project Report ordering information at back). Introduction Disposal of sludge produced during municipal wastewater treatment is a severe problem. To select a disposal method, an agency must consider numerous factors, including costs, pro- tection of the public health, pollution of air, water, and land, public acceptance, and resource conservation and recov- ery. Land application of stabilized sew- age sludge has become a viable sludge disposal option. Benefits of this method result from the use of sludge as a low- analysis fertilizer and soil conditioner. When the city of Indianapolis, Indi- ana, was required to construct advanced wastewater treatment facili- ties at the existing Belmont Wastewater Treatment Plant, they determined that ------- the most cost effective site for these new treatment facilities was the 10 sludge lagoons containing 420,000 m3 (111 million gal) of digested sewage sludge for up to 50 years. Of the 420,000 m3 of sludge originally con- templated for disposal by land spread- ing, 265,000 m3 was actually spread on land and the remainder disposed of in a landfill. The site preparation contract was awarded to a contractor who chose to dispose of the lagooned sludge by applying it to privately owned agricultu- ral cropland in adjacent Boone County, Indiana. Procedures The project consisted of the following major tasks: (1) obtaining approval from regulatory agencies; (2) obtaining coop- eration of landowners and farmers; (3) removing, transporting, and applying the lagooned sludge to soil; and (4) monitoring the impact on crops. Undefined state and Federal regula- tions hampered initiation of the project. To determine appropriate rates for sludge application on cropland, exten- sive analyses were conducted of the sludge stored in the lagoons. As expected, the sludge solids content was extremely variable, ranging from U1% near the surface to "30% at a 5-m depth. The Cd and PCB contents of the sludge were major constraints in determining sludge application rates to cropland. The Cd concentrations ranged from 122 to 241 mg/kg (with an average of 179). Sludge application rates were initially based on 1.1 kg Cd/ha and later increased to 2.1 kg/ha. The maximum amounts of lead (Pb), zinc (Zn), nickel (Ni), and copper (Cu) applied-were less than 26,48, 22, and 2.6 kg/ha, respec- tively. Corn and soybeans were the crops grown after a single soil applica- tion of the sludge. The subcontractor responsible for the sludge application developed an effec- tive public relations program involving demonstration plots, radio and news- paper advertising, and written mate- rials. Landowners consigned about 5,000 ha (13,000 acres) for sludge application. The subcontractor col- lected the soil samples, provided soil and sludge analysis data, and applied limestone when the soil pH was below 6.5. The sewage sludge was resuspended in each lagoon, pumped into semi- trailer tankers, trucked to Boone County, and either applied immediately or placed in temporary storage lagoons. A variety of equipment was used to sur- face apply or inject the sludge into soil. Adverse weather conditions reduced the time available for sludge application and thereby delayed project completion by several years. Discussion Sludge Disposal Procedures A high rate of sludge handling was achieved by using procedures and equipment developed in similar bulk material handling industries. A cable- controlled, pontoon-mounted device was used to homogenize and move the sludge in the lagoons to a pump station for transfer to a truck loading station. Four large semi-trailer tankers could be loaded in 5 min at the bulk-fuel-oil type loading facility. Each tanker truck transported 29.5 m3 of sludge over 80 km (50 miles) to an adjacent county where it was again transferred to a field-spreading vehicle or to an interim sludge-holding lagoon. A variety of spreading equipment was used over the 4-year sludge speading period. The contractor initially used low-speed, agricultural-type equip- ment. This equipment was unable to maintain high rates of sludge applica- tion on a round-the-clock basis. The heavier, faster, construction-grade spreading units used in the last 2 years of the project demonstrated the availa- bility of equipment for large-scale land application of sludge projects. Summar- ized specifications for this type of equip- ment are included in the report. Public Relations Even though a technically sound sludge application program might be designed, public opposition could pre- vent the program from being initiated. The contractor therefore realized that an effective public relations program was essential to insure acceptance of sludge utilization in the county where sludge was to be spread. Two sectors of the public were addressed by the public relations program: The farmers who were to receive the sludge, and their neighbors. The farmers needed to be convinced of the economic benefit of using sludge, which in their experience was an unknown soil amendment when compared with conventional fertilizers. The neighbors of the farmers were sen- sitive about the dumping of urban wastes in rural communities, and their concerns included odors, pathogens, and groundwater pollution. The contractor addressed the public relations problem with a broad approach that included: (a) establishing good media relations, (b) holding group meetings, (c) carrying out test plot dem- onstrations, (d) having a motion picture of the project prepared for loca I viewing, and (e) gaining the active Support of agronomy experts. Retention of a Consulting Agronomist The city identified a need for a person with special expertise in the field of sludge disposal on agricultural land. In addition to providing technical assist- ance, this consultant provided addi- tional project credibility with both the general public and the regulatory agen- cies. At the request of the city, the con- sulting agronomist prepared an evaluation of the agronomic implica- tions of the land application of sludge for this project. He concluded that the project was well designed and incorpo- rated the latest concepts for land appli- cation of sludge. The consulting agronomist supported the Indiana State Board of Health (ISBH) requirements for continuous monitoring of the sludge removal and spreading operations. He continued to be associated with the pro- ject in a consulting role and was involved in designing a program for sampling and analyzing the corn and soybean crops raised on sludge-treated fields. Crop Monitoring The state regulatory agency required that samples of corn and soybean grain be collected and analyzed the first year after sludge applications. Random sam- ples of grain were collected by hand harvesting in September of each year. Samples were collected from both the sludge-treated fields and adjacent fields not treated with sludge. Because the same varieties of corn and soybeans were not necessarily grown in adjacent fields, the comparisons of Cd and PCB concentrations in crops grown on sludge-treated and non-sludge-treated areas (Table 1) may reflect the influence of both crop variety and sludge applica- tion. All crop samples were obtained during the first cropping season after sludge application. In 1978, some corn grain samples showed slightly increased concentrations of Cd. No Cd or PCB's were present at detectable lev- els in any subsequent samples of corn and soybean grain. ------- Table 1. Concentrations of Cadmium and PCB's in Corn and Soybean Grain Grown on Sludge-Treated and Untreated Soils in Boone County, Indiana (ug/kg) PCB in Grain Cd in Grain Year 1978 1979 1980 Crop Sludge-Treated Corn (9f <1 Soybeans (6) <1 Corn (9) <1 Corn (12) <1 Untreated 1 Sludge-Treated 100 60 <50 <50 Untreated <20 <50 <50 <50 a The numbers in parentheses indicate the total number of samples analyzed. Conclusions This project demonstrates that a met- ropolitan treatment plant can remove and apply to croplands a large volume of liquid stabilized sewage sludge that has been stored in lagoons. The project involved transportation of the sludge by semi-trailer tankers and either surface or subsurface application to cropland with conventional equipment. The sludge was applied on privately owned land in an adjacent rural county through a cooperative agreement between the farmers and contractor. The planning and conduct of a land application project requires expertise in many technical and sociological disci- plines. Critical areas identified during this project include materials handling and transport, public relations, sludge application equipment, soil and crop production, soil and groundwater moni- toring, sludge application and crop pro- duction scheduling, experience in relating to farmers and their problems, obtaining regulatory approvals, and establishing the mechanism for flow of project data and information. Adverse weather conditions caused delays in applying sludge to farmland, and the growth of row crops (corn and soybeans) minimized the number of days that sludge could be applied to soils. Coordination of crop production and sludge utilization programs is diffi- cult because of uncertainties caused by adverse weather conditions. A public relations program must be started very early in a project to obtain the support of the agricultural commun- ity. Both the benefits and problems must be presented to all interested par- ties. The project developed numerous procedures for monitoring sludge appli- cation rates and for maintaining a wide variety of records. The equipment initially chosen for applying sludge did not perform as anticipated. Alternative equipment was selected later that could withstand continuous use. All equip- ment should be evaluated onsite before purchase. A single application of sewage sludge at a rate ranging from 1.12 to 2.1 kg Cd/ha caused no measurable increases in the Cd content of corn and soybean grain. Plant uptake of PCB's was also not detectable. If at all possible, off site storage of sludge in either temporary or perma- nent lagoons should be avoided. A far preferable procedure is to locate stor- age lagoons near the treatment plant and then transport the sludge just before it is to be appl ied to cropland. The two temporary storage lagoons near the sludge spreading site resulted in the only negative public response to the land application project. This project demonstrates that a large metropolitan sanitary district can trans- port and apply sludge to cropland in a neighboring rural area without wides- pread public resistance. To accomplish this goal, it is essential to involve local agricultural leaders, develop an effec- tive and honest public relations pro- gram, use aesthetically acceptable methods for sludge application, and develop sludge application procedures compatible with prevailing farming practices. The full report was submitted in ful- fillment of Contract No. C2575NASX by C. Michael Robson under the sponsor- ship of the U. S. Environmental Protec- tion Agency. C. Michael Robson and Lee E. Sommers are with Purdue University, West Lafayette, IN 47907. Gerald Stern is the EPA Project Officer (see below). The complete report, entitled "Spreading Lagooned Sewage Sludge on Farm- land: A Case History," (Order No. PB 82-181 082; Cost: $12.00. subject to change! will be available only from: National Technical Information Service 5285 Port Royal Road Springfield. VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Municipal Environmental Research Laboratory U.S. Environmental Protection Agency Cincinnati. OH 45268 •ft US GOVERNMENT PRINTING OFFICE. 1982 — 559-017/0728 ------- United States Center for Environmental Research Environmental Protection Information Agency Cincinnati OH 45268 Agency EPA 335 V _ Official Business Penalty for Private Use $300 RETURN POSTAGE GUARANTEED Third-Class Bulk Rate MERL0063240 LOU W TILLEY REGION V EPA LIBRARIAN 230 S DEARBORN ST CHICAGO IL 60604 ------- |