Removal of nitrogen from tile drainage
Subtitle: a summary report.
By: Based on reports prepared by the California Department of Water Resources; Environmental Protection Agency, Water Research Center [and] Environmental Protection Agency, Region IX.
Contributors: United States. Environmental Protection Agency. Water Research Center.; United States. Environmental Protection Agency. Region IX
Series: Water pollution control research series; Bio-engineering aspects of agricultural drainage, San Joaquin Valley, California
Publisher: [Environmental Protection Agency, Office of Research and Monitoring] For sale by the Supt. of Docs., U.S. Govt. Print. Off.
Published: 1971
Place of publication: Washington
Language: eng
Number of pages: 30
Subjects: Water -- Purification.; Nitrogen.
Description: Studies have shown that it is technically feasible to reduce 20 mg /l nitrate-nitrogen in agricultural tile drainage to 2-5 mg/l by either algae stripping or bacterial denitrification. Conditions necessary for maximum algal growth included 8- to 12-inch pond depth, addition of small amounts of nutrients (CO₂, Fe, and P), up to four hours of daily mixing and detention times of from 5 to 16 days, depending on the season. The algae were harvested by coagulation-sedimentation followed by vacuum filtration. Bacterial denitrification was tested in anaerobic deep ponds and filters using methanol as a carbon source. Required detention times were on the order of 8 to 50 days for covered ponds (uncovered ponds were not suitable) and 1 to 2 hours for filters. Preliminary cost estimates are given. Laboratory studies indicated that nitrogen removal effectively lowered the biostimulatory nature of the waste with respect to algal growth in potential receiving waters. Two desalination processes were also studied -- electrodialysis and reverse osmosis.
Notes: "13030 ELY 5/71-6; REC-R2-71-6; DWR no. 174-9; DWR-WOO grant no. 13030 ELY; DWR-USBR contract no. 14-06-200-3389A"

"The agricultural drainage study was conducted under the direction of: Robert J. Pafford, Paul De Falco [and] John R. Teerink"

Bibliography: p. 27.