Experimental Reasearch On Sludge Treatment Technology In Water Purification Plant

Water purification plants produce a lot of wastewater during the production of drinking water,accounting for about 2% to 10% of the water produced by the water purification plant.With the continuous development of society and the increasing demand for drinking water,the scale and number of water purification plants are constantly increasing.As a result,the amount of production waste water generated also increases.The sludge contains a large amount of colloidal particles,suspended solids,coagulants,and hydroxides produced by the coagulant.After the sludge discharged from the water purification plant is directly discharged into the water body,it will cause a certain degree of pollution to the environment.The treatment of the discharged mud water not only protects the environment but also saves water resources.This study investigated the treatment of sedimentation sludge from a sedimentation tank in a purification plant in northern China.The raw water source and quality of the influent water in the water purification plant,as well as the quality of the sludge discharged from the sedimentation tank were analyzed.Using the formula for calculating the amount of waste water and sludge in the production process,the amount of sludge discharged and the amount of sludge produced can be determined.The sedimentation performance of sedimentation ponds was analyzed.When the sludge concentration was high,the sedimentation performance was poor.Using the method of coagulation and sedimentation,use a variety of coagulants to coagulat e sludge in sedimentation tanks,select the best coagulant for PAM,the optimal dosage is 10mg/L,PAM after coagulation for 20 minutes Precipitated sludge concentration rate will not change significantly.The lower the sludge concentration,the lower the m oisture content of the precipitated sludge that is coagulated by PAM at the same time.By centrifuging the sludge,the time is best when the centrifugal speed is 4000 rpm and the centrifugation time is 15 minutes.The higher the sludge concentration,the h igher the moisture content of the centrifuged sludge.The gravity sedimentation supernatant water quality is slightly poorer,and a small part of the test items are higher than the National Standard for Drinking Water Sanitary Standards(GB5749-2006).The supernatant can be mixed with the water purification plant influent water.The natural sedimentation sludge is treated with a ceramic membrane,which can slow down the membrane blockage under aeration conditions.By comparison,the appropriate starting membrane fluxes are continuously operated.Analyze the condition of clogging of the ceramic membrane with different operating conditions and determine the appropriate membrane cleaning conditions.Using various optimum conditions,the ceramic membrane was treated with an intermittent backwashing process to concentrate the natural precipitated mud water approximately 5 times.The sludge treated by the ceramic membrane was treated by centrifugation.The solid content of the concentrated sludge was close to 4%.T he water quality of the centrifugal separation water is slightly poor,and it can be mixed and treated together with the water purification plant.The effluent of the ceramic membrane meets the National Standard for Drinking Water Hygiene(GB5749-2006),and the effluent can be treated together with the filter.The economic analysis of the sludge pretreatment by three methods of coagulation settlement,ceramic membrane treatment,and gravity settlement shows that gravity sedimentation has the lowest pretreatment cost for sludge removal.The pretreated sludge was concentrated by a ceramic membrane treatment method and then further separated by centrifugation.The economic cost of treatment was 1.70 yuan/ton.