Study On The Technology Of Domestic Sewage Treatment By No-Media Hydroponics Plant System

In view of the city life sewage, this paper designed a no-media hydroponics plant system to research the treatment effects, including the development status of plants and biofilm growth. The experimental results were showed as follows:(1) The average influent concentrations of COD, NH3-N, TN, and TP were 104.4mg·L-1,39.3mg·L-1,26.7mg·L-1, and 3.3mg·L-1, respectively. The average effluent water yield of spinach system were 35.1mg·L-1, 1.9mg·L-1, 5.5mg·L-1, and 0.3mg·L-1, respectively. And the removal rates were 66%,93%,86%, and 90%, respectively. The average effluent water yield of rice were 39.6mg·L-1,2.6mg·L-1,6.9mg·L-1, and 0.8 mg·L-1, respectively. And the removal rates were 62%,90%,83%, and 77%, respectively.(2) The quality of sewage effluent is related to the concentrations of the sewage influent. With the increasing of pollutants concentrations in sewage influent, the concentrations of sewage effluent increases. While the concentration of COD, NH3-N and TN were less than 108 mg·L-1,32 mg·L-1 and 47 mg·L-1, respectively, the quality of the water can reach the national standard of Urban Sewage Treatment Plant Emission Standards (GB 18918-2002).(3)With the increasing of the reaction stages, the standard deviation and variation coefficient of COD, NH3-N, TP, and TN in single stage were decreased, and the stability of the system was improved. At the same time, adding the reaction stages was conducive to realize microbial structure and function division, and then system operated more efficiently in terms of a single stage removal rate, independent removal rate, per unit area of biofilm removal load and the change of unit mass of biofilm removal load.(4)The plant biomass was increased in the time-dependent manner. And the reproductive growth of plants was influenced by the elements of P and N. In the test, the amount of rice scion increased first and then decreased, and the amount of rice scion was most in the third stage.(5) In the system, the development of biofilm was affected by pollutants and plant species. Stage ?, Stage ?, Stage ?, and Stage? of biofilm biomass of per unit area in swamp cabbage system were 1.60 g·m-2,1.33 g·m-2,0.63 g·m-2, and 0.28 g·m-2, respectively. Stage ? Stage?, Stage?, and Stage? of biofilm biomass of per unit area in rice system were 1.22 g·m-2,0.31 g·m-2,0.24 g·m-2,0.17 g·m-2, respectively.