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Long‐Term Wastewater Treatment Effectiveness of a Northern Wisconsin Peatland
Author(s) -
Nichols Dale S.,
Higgins Dale A.
Publication year - 2000
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2000.00472425002900050043x
Subject(s) - peat , effluent , phosphorus , environmental science , nutrient , wastewater , sewage treatment , sewage , environmental engineering , hydrology (agriculture) , chemistry , ecology , biology , geology , geotechnical engineering , organic chemistry
Secondary effluent from the Drummond, WI wastewater stabilization lagoon system was applied to an acidic, nutrient‐poor, 8.3‐ha peatland for the purpose of advanced wastewater treatment. Application occurred from June through October at an average rate of 10 cm yr −1 from 1979 to 1982, 24 cm yr −1 from 1983 to 1988, and 40 cm yr −1 from 1989 to 1996, increasing surface flow from the application area by 47, 78, and 154%, respectively. The pH of the peatland outflow increased from 4.2 to 6.7, chloride rose from 1.1 mg L −1 to 80 mg L −1 , and total phosphorus increased from 0.05 mg L −1 to 0.6 mg L −1 . Because raw sewage input was only one‐half of the lagoon system's design capacity, the lagoons provided a high degree of sewage treatment, removing 95% of suspended solids (SS), biochemical oxygen demand (BOD), and nitrogen from the wastewater stream. Phosphorus removal in the lagoons, which was 98% in the first years of operation, declined to 85% by 1995. The peatland contributed little additional treatment, removing only 37% of the nitrogen and 17% of the phosphorus remaining in the lagoon effluent. The peatland's capacity to retain phosphorus was exhausted after a few years of application. Increased pH, nutrient availability, and water levels altered the peatland vegetation community. The Sphagnum ground cover was reduced or eliminated in many places, and dense stands of cattail ( Typha sp.) developed in some areas. Small peatlands such as this one seem poor candidates for use as tertiary treatment systems.