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CE 521 Environmental Biotechnology

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Term Paper Abstracts (Fall 2001):

SWINE WASTE TREATMENT IN CONSTRUCTED WETLANDS: A  REVIEW OF MECHANISMS, DESIGN PROCEDURES, AND RESULTS

by Aron D. Butler

 ABSTRACT

             Sustainable and inexpensive swine waste treatment alternatives are increasingly important as hog production operations continue to increase the number of animals being raised in a given facility.  In 2000, the number of U.S. hogs in operations with more than 5,000 animals increased by 4% from 1999, while all smaller operations decreased in size (USDA, 2001).  Constructed wetlands have been shown to be a viable option for secondary treatment between the lagoon and the final land application site, reducing odors and application area required.  Pollutants of interest are typically BOD, TSS, nitrogen, phosphorus, metals, and pathogens.  Removal mechanisms are both physical and biological, including processes such as sedimentation and filtration as well as microbial decomposition, conversion, and assimilation.  Wetlands models are based on first order plug flow kinetics with modifications.  Two popular design procedures are outlined here, and some results are given.  Typical removal efficiencies are: BOD, 38%; TSS, 86%; total nitrogen, 61%; ammonia nitrogen, 76%; phosphorus, 55% (SCS, 1995).

 Keywords: swine waste, treatment wetlands, phosphorus removal, nitrogen removal, Presumptive Method, Field Test Method, nutrient cycling, sedimentation 

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