Constructed wetlands for livestock wastewater management

In 1995, the Gulf of Mexico Program (GMP) sponsored efforts by the Alabama Soil and Water Conservation Committee and the National Council of the Pulp and Paper Industry for Air and Stream Improvement (NCASI) to conduct a revi ew of the literature concerning the use of constructed wetlands for treatin g concentrated livestock wastewaters. The scope of the literature review an d summary of design/operation data included all of North America. Both publ ished and unpublished data have been provided by researchers to be included in the database. The database format used for the GMP project is only slig htly modified from the format developed for the US Environmental Protection Agency (EPA) North America Treatment Wetland Database, which includes info rmation from municipal, industrial and stormwater treatment wetlands. The G MP Livestock Wastewater Treatment Wetland Database includes information fro m 68 sites with a total of 135 pilot and full-scale wetland systems (system s include parallel units at individual research facilities), Types of lives tock wastewater being treated by constructed wetlands include dairy manure and milkhouse wash water, runoff from concentrated cattle-feeding operation s, poultry manure, swine manure and catfish pond water. Over 1300 operation al data records are summarized in the database. These data indicate that re moval rates for 5-day biochemical oxygen demand (BOD5), total suspended sol ids (TSS), ammonium nitrogen (NH4-N), total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD) and fecal coliforms are potentially ver y high in constructed wetlands receiving animal wastewaters. Average concen tration reduction efficiencies were: BOD5 65%, TSS 53%, NH4-N 48%, TN 42%, and TP 42%. Removals are a function of inlet concentrations and hydraulic l oading rates. Successful wetland design must include adequate pretreatment to protect the health of the wetland biota and must include adequate wetlan d area to meet the quality goals. (C) 2000 Elsevier Science B.V. All rights reserved.