Influence of Rural Sewage Effluent on Riverine Water Quality and Microflora

Abstract

In this study, the impact of rural sewage effl uent on the water quality of an agricultural water channel and rural river was investigated. Treated water samples from rural sewage, an agricultural water channel, and a rural river were analyzed. In addition, microfl ora analyses were conducted on the sediments and water samples from each location using the quinone profi le methodology. The results revealed the critical need to study the impacts of treated sewage effl uents on freshwater ecosystems. The nitrogen and phosphorus concentrations of water in the agricultural water channel increased downstream of the treated wastewater TW infl ow. The annual average nitrogen and phosphorus concentrations in the TW were 7.33 mg L -1 and 1.83 mg L -1 higher, respectively, than those measured in the agricultural water channel upstream of the reclaimed wastewater infl ow. Furthermore, a slight increase in the sediment microbial biomass, determined by the loss-on-ignition method, was observed in the treated water fl owing into the agricultural water channel. It was clarifi ed that rural sewage effl uents with a high concentration of nutrients affect the microfl ora in the agricultural water channel, and, in particular, contribute to the increase in the amount of denitrifying bacteria.