A Experimental Study On The Efficient Technology To Water Plant Wastewater Treatment In Shenzhen City

Wastewater discharged directly from water plant not only leads to clogging of received water-body, but also wastes vast amount of water resource. Engineering practice and experimental study on treatment and reuse of wastewater has been developed in many domestic and foreign water plants in order to protect environment and save water resource. For the particular geographical and climatic conditions, wastewater of water plant in Shenzhen city has such characteristics as high organic matter content, easily zymolytic and poor sediment ability and dewaterability. Traditional treatment process couldn't fit for it. Thus, the experimental study on wastewater of Shenzhen water plant was carried on to find a new efficient treatment process.Traditional treatment processes were introduced at first, and then experimental study on sludge conditioning theory was developed. Based on the experimental results, an integret theory-Capillary model was put forward and used to interpret all sludge conditioning methods. The Capillary model considers the sludge dewaterability is determined by coeffcient of compressibility S, sludge particle size distribution uniformity T, filtrate absolute viscosity ,capillary length / and particle size d and its expression is P = .Thesmaller S and , the better sludge dewaterability, and the larger l, T and d suggests better sludge dewaterability.The experimental study on wastewater treatment of Shenzhen water plant by pelleting fluidized bed technology (PFBT) was developed to verify the possibility of this new efficient concentration technology. Before this, laboratory screening polymers was carried out, and FO4240SH, PAM-IIand PHP-IV were selected for sludge conditioning. The experimental results shew PFBT could significantly improve sludge thickening performance and reduce sludge thickening time. Under the experimental condition, particle sediment speed can beenhanced from 0.00047-0.0087 mm/s to 0.42~6mm/s and sludge thickening time can be shorten from 8~12h to 10~30min.; PFBT could greatly enhance sludge concentration within a short period of time. Under the experimental condition, sludge concentration can be enhanced from 2000~5000mg/L to 18000~35000mg/L within 10-30 minutes; PFBT could significantly improve sludge dewaterability. Using each polymer, SRF can be reduced to a value below 5 1011m/kg and the sludge can be easily dewatered; The effluent water quality was stable. Its turbidity was 6-30NTU and color was 30-40 and pH is 7.5-8.0. Compared with traditional treatment processes, PFBT has many advantages, such as high efficiency, good sludge thickening performance, low dosage, small area, and simple operation. This new process is more suitable for treatment of wastewater of Shenzhen Water Plant.At last, the wastewater treatment processes in Meilin Water Plant were investigated, some problems during the processes were pointed out and some improved methods were put forward.