Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/1999
Publication Date: N/A
Technical Abstract: Constructed wetlands used for wastewater treatment are generally limited by nitrification. This is particularly true for those used for animal wastewater treatment. To resolve this problem, various methods of pre-wetland nitrification have been investigated. One of these methods makes oxidation an integral part of the constructed wetland via a Marsh-Pond-Marsh (MPM) design. In this design the first section of marsh/wetland removes BOD. The subsequent pond section promotes growth of aquatic flora and the associated photosynthetic production of oxygen. The combined effect of these two cells is to make conditions favorable for nitrifying bacteria and conversion of significant quantities of ammonia to nitrate. The nitrate is subsequently denitrified particularly in the final marsh stage. The investigated MPM wetlands were located in Greensboro, NC, and have been used intermittently for the treatment of swine wastewater for rabout two years. Initial denitrification enzyme assay values were low relative to values obtained from other wetlands in NC that were of simple "marsh only" design. This was true for the control as well as the nitrate and carbon amended treatments. However, this may change as the system is operated continually and at high loading rates.