Investigation Of Sewage Treatment Facilities And Study On Enhanced Phosphorus Removal By Its Core Processing Unit In Southern Rural Areas

Owning to the present economic state, the living habits of people and many other factors in rural areas in China, most rural domestic sewage is discharged without any treatment, which affects the water resources and does great harm to the living conditions. Therefore, it is essential to resolve the problem. Compared with cities, the economy in rural areas is not so developed, and the technical and managerial personnel are not adequate, which should be taken into consideration in sewage treatment. After an investigation of the rural sewage treatment facilities in Southern Drainage Basin, it is believed that constructed wetland is practical as the core processing unit.Generally, the removal rate of organic pollutants and nitrogen by constructed wetland is high, but that of phosphorus is not so satisfactory. Fly ash brick can be used as the substrate for enhanced phosphorus removal in constructed wetland. This paper studies P removal efficiency of FAB through isothermal adsorption experiments and constructed-wetland model experiments.The P adsorption capacity of FAB and various influencing factors are studied through isothermal adsorption experiments. The result shows:P adsorption of FAB could be well simulated by Langmuir and Freundlich isotherm equation, and the theoretical maximum of P adsorption by FAB is to be 21277mg/kg; the main content s of FAB are SiO2, CaO, Al2O3 and a little Fe2O3, and there isn't much change during the experiment, but the P content in FAB increased in large amount after adsorption in accordance with X-ray fluorescence analysis. When other reaction conditions stay the same, the longer the reaction time is, the smaller the grain diameter of FAB is, and the higher the temperature is, the higher the removal efficiency is.Constructed wetland model is built to study the P removal efficiency of stimulant wastewater and the data shows when the P concentration in raw water is about 3mg/L, nearly all the phosphate is removed. The first two models are run to study the influence of hydraulic load on P removal efficiency, and it is found that the P removal efficiency is decreased as the hydraulic load increases.The urban sewage around the South Lake is used as raw water to verify the P removal efficiency of FAB wetland in real life. The result shows:the P in raw water mainly consists of TDP, whose largest component is SRP; the SRP removal is accomplished well and its content in effluent is less than 0.03mg/L; the PP removal is completed unsatisfactorily through the physical buffer by substrate, and the P removal efficiency is about 50%; the concentration of other forms of P in TDP like dissolved organic phosphorus and condensation phosphate is less than 0.05mg/L in influent, and theirs are not remarkable. The main component of the raw water in FAB wetland is PP and the effluent can meet I A standard in TP content, according to "Municipal Wastewater Treatment Plant Pollutant Emission Standards" (GB18918-2002), and the effluent is of stable quality.Different forms of P in domestic sewage in Hongxia Village and South Lake are analyzed comparatively and the result shows:there exists some similarities between the Hongxia Village sewage and South Lake sewage, mostly TDP, which mainly consists of SRP. FAB wetland is effective in the treatment of Nanhu urban sewage, hence it is safe to assume that it will also be feasible in sewage treatment in villages like Hongxia Village.