Abstract
The microbiological quality of treated waste water is always a concern when waste water is disposed to the environment. However, when treated appropriately, such water can serve many purposes to the general population. Therefore, the treatment and removal of contaminants from swine waste water by continuous flow-constructed wetlands involves complex biological, physical, and chemical processes that may produce better quality water with reduced levels of contaminants. Swine waste contains E. coli populations and other bacterial contaminants originating from swine houses through constructed wetlands, but little is known about E. coli population in swine waste water. To assess the impacts of seasonal variations and the effect of the wetland layout/operations on water quality, E. coli isolates were compared for genetic diversity using repetitive extragenic palindromic polymerase chain reaction (REP-PCR). None of the isolates was confirmed as Shiga toxin producing E. coli O157:H7 (STEC); however, other pathotypes, such as enterotoxigenic E. coli (ETEC) were identified. Using a 90% similarity index from REP-PCR, 69 genotypes out of 421 E. coli isolates were found. Our data showed that the E. coli population was significantly (p = 0.036) higher in November than in March and August in most of the wetland cells. Furthermore, there was a significant (p = 0.001) reduction in E. coli populations from wetland influent to the final effluent. Therefore, the use of continuous flow-constructed wetlands may be a good treatment approach for reducing contaminants from different waste water sources.
Highlights
Continuous flow-constructed wetland is a natural process for the treatment of waste water [1,2,3].It is an alternative to conventional technologies for wastewater treatment [2]
The present study looks at E. coli serotype identification, population structure, and genetic diversity of E. coli in a surface flow-constructed wetland systems in association with continuous flow ponds
We previously showed a 98% decrease in E. coli with subsurface constructed wetland, and this reduction was significantly correlated with TN, NH+ 4, total phosphorous (TP) and PO3− 4 decreased from influent to effluent in the wetland [2]
Summary
Continuous flow-constructed wetland is a natural process for the treatment of waste water [1,2,3].It is an alternative to conventional technologies for wastewater treatment [2]. Continuous flow-constructed wetland is a natural process for the treatment of waste water [1,2,3]. Swine waste is high in dissolved and particulate organic matter, ammonia and organically bound phosphorus and nitrogen as well as biological oxygen demand, and other contaminants. Swine waste may contain E. coli, protozoan parasites such as Cyrptosporidium and Giardia, as well as viruses. E. coli can be transported through storm water after a heavy rainfall washing infected manure into the farming community’s wells and subsequently contaminating ground water and soil. Water contamination by E. coli is becoming common in rural areas of the United States, with up to 40% of tested wells found to be contaminated [4]
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