Study of the Pollution Features of Domestic Sewage in Zhuzhou City

The water quality of domestic sewage in Zhuzhou City was monitored at 4 different positions for one year (4 seasons per year, 3 days per season and 4 times per day).The monitoring results show that BOD 5 and Inorg P were two main pollutants in domestic sewage and that with the alteration of sampling time and sampling site, concentrations of pollutants in domestic sewage changed in a certain pattern.Firstly, the pollution level in noon and dusk was higher than that in morning and midnight;Secondly,in winter and spring, the domestic sewage contained more pollutants than the other two seasons;Thirdly,the domestic sewage from the site containing thick population and restaurants was polluted more seriously than that from the business quarter and mixed parts.Over 60% of total nitrogen and phosphorus in domestic sewage existed in the form of inorganic salts;At present, there is no evident difference in annual production between domestic sewage and industrial wastewater from the primary pollution sources and meanwhile,the total quantity of BOD 5 and CODcr in domestic sewage has been larger than that in industrial wastewater.So,the pollution pressure from domestic sewage on Xiangjiang River should not be ignored.Higher biodegradability (BOD 5/CODcr)and suitable CODcr/T P value in domestic sewage of Zhuzhou City indicated that biological purification would eliminate this kind of pollution effectively.