Evaluation of free water surface constructed wetlands for treatment of livestock waste in Indiana

Richard Paul Reaves, Purdue University


Interest in the use of non-traditional waste management systems is increasing. This research determines the feasibility of using free water surface constructed wetlands for wastewater treatment on dairy and swine operations in northern Indiana. Research was conducted on a 16-cell in parallel constructed wetland system at the Purdue University Animal Sciences Swine Research Complex, a 3-cell in parallel constructed wetland system at Norwood Farms, Inc., and a 2-cell in series constructed wetland system at Tom Brothers Dairy. All sites are in the northern third of Indiana. Data were collected from Norwood Farms in 1993 and 1994, and from Purdue University and Tom Brothers in 1994 and 1995. Constructed wetlands may be used as components in total animal waste management systems. These systems reduce levels of nutrients in wastewater, reducing the amount of land needed for final disposal of wastewater through land application. Reductions in carbonaceous biochemical oxygen demand, fecal coliform bacteria, total suspended solids, phosphates, total phosphorus, ammonia-nitrogen, and total nitrogen have been achieved with both dairy and swine wastewater. Constructed wetland systems require that raw wastewater be pretreated in lagoons, or similar separation systems, to remove solids from the waste stream. Operators must perform routine system maintenance and follow year-round management plans for wetland systems to be successful. Chemical tracers show that unlined systems, placed on farms where soils have low hydraulic conductivity, pose little threat to groundwater contamination. Designs that incorporate multiple cells in series are recommended. Alternating areas of open water with vegetated areas within wetland systems should improve treatment of ammonia-nitrogen and phosphates. An initial open water area should be used if influent suspended solids levels are above 500 mg L$\sp{-1}.$




DuBowy, Purdue University.

Subject Area

Agricultural engineering|Environmental science|Environmental engineering

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