Characteristics of Domestic Wastewater Quality and Quantity Discharged from Typical Villages and Small Towns by the Riverside in Three Gorges Reservoir Region

To understand the pollution condition of sewage from typical villages and small towns by the riverside in Three Gorges Reservoir and to conduct the wastewater treatment engineering design,the characteristics of domestic wastewater quality and quantity from Shibao village and small town in Chongqing were investigated by using on-site sampling and the experimental analysis from May to November in 2008.The results showed that the domestic wastewater discharged from this type of towns had the characteristics of high nitrogen,medium phosphorus and low organic matter concentration with the low carbon nitrogen ratio.Inorganic forms of nitrogen and phosphorus were dominant.The flow rate and the concentrations of different pollutants in the wastewater changed over time with a general identical tendency in a whole day,but the variations in the scale of hours differed.Wastewater flow rate and TP concentration showed obvious differences in different functional days.However,the concentrations of COD and TN had no significant changes.With the variation of water-consuming activities as a result of the monthly changes of temperature and the seasonal distribution of rain water,wastewater flow rate varied significantly in the study period(from May to November),and the concentrations of main pollutants also exhibited a similar variation trend,the concentrations of pollutants in June and November were obviously higher than the other months in the monitoring period.The above mentioned variation tendencies of wastewater flow rate and pollutants concentrations basically reflected the characteristics of domestic wastewater discharging,the life styles and living schedules of local residents at typical villages and small towns by the riverside in Three Gorges Reservoir Region.