Application Of High Pressure Filtration Dewatering And Consolidation Integration Technology In River Silt Treatment

Due to long-term pollution for many years,a large number of pollutants such as garbage and silt are deposited at the bottom of the river bed.These pollutants will affect the water quality of the river for a long time.In the dredging project of the river,a large number of dredged silt with high water content,high organic matter and high microbial content will be produced.The sludge is highly polluted due to its contaminants,such as pathogens,organic debris and heavy metals.The content of organic matter and nutrients in the sludge is relatively higher.The sediment polluted by oxygen-consuming organic matter is often black,gray-black and easy to re-suspend,which is the main cause of black and odorous water.The water content of river sediment is generally maintained above 95%,so the precondition of sediment treatment is how to reduce its water content quickly.At present,most of the sludge treatment technologies adopted at home and abroad are simple dewatering and consolidation.The nature of the sludge after simple treatment is not stable,and the purpose of"reducing,stabilizing and harmlessness"of the treated sludge can not be realized.Therefore,how to achieve successful consolidation It is urgent to apply silt cleaning and treatment,restore ecological rivers,repair polluted water bodies,as well as efficient and useful River silt treatment means or core technology requirements for water conservancy projects.This paper mainly studies how to use effective technology to treat sludge with high water content,low shear strength and heavy metal pollution.The main object of study is to select a practical case of a river comprehensive regulation project for research and analysis.The main research results are as follows:?1?Based on the siltation of river silt and the present situation of black and odorous water body in water conservancy projects,a comprehensive analysis is carried out.Samples are made in the test area,and the basic properties and corresponding characteristics of silt and water quality are analyzed.The results show that the environmental pollutants produced by the rapid development of industry and agriculture at different levels are serious endogenous pollution.The basic reason for low carrying capacity of the environment and the loss of self-purification ability of water body directly causes water pollution and harms to organisms and ecosystems;?2?According to the biochemical pollution indexes of sediment and water body,the causes of pollution were analyzed.The monitoring results of water body showed that the indexes of dissolved oxygen,CODcr,BOD₅,ammonia nitrogen,total phosphorus,total nitrogen,petroleum,anionic surfactant and fecal coliform group in the water body of the monitoring points exceeded the limits of the standard.Among them,dissolved oxygen,ammonia nitrogen,total phosphorus,total nitrogen and fecal coliform flora exceeded the standard most seriously,with the maximum exceeding multiples of 6.1,10.1,4.8,12.1 and17.0,respectively.The monitoring results of sediment showed that the organic matter content of the current river silt in the test area was higher,and the nitrogen,phosphorus and potassium contents in the silt were 0.37%,0.41%,2.06%,respectively.The pollution of heavy copper,zinc,nickel and cadmium is the most serious,and the biological toxicity of the sludge is high,so it can not be used as a nutrient soil for crop cultivation;?3?Through comprehensive analysis and comparison in many aspects,this paper draws a conclusion that the dredging scheme of silt adopts wet dredging method,the dredging machinery adopts environmental protection cutter suction dredger,and the dredging method adopts cutter suction dredger equipped with fully enclosed long-distance slurry pipeline transportation;at the same time,this paper establishes a feasible design of sludge dewatering and consolidation.According to the characteristics of high organic matter content and very fine granular sludge in urban rivers,the sludge separation and treatment system is specially designed and manufactured.The core technology is to use PAM?polyacrylamide abbreviation,Chinese name is polyacrylamide?anionic AN910SH and PAM cationic C4101 with a mass of1:1.The mixture is used as dehydrating agent,TNM1?mainly MgO-CaO-SiO₂?is used as consolidating agent,and high pressure filter dehydrator is used;?4?This paper makes a comprehensive analysis of the treatment capacity,compressive strength,binding capacity of heavy metals,seed germination rate and sludge leachate of the high pressure pressure pressure filtration system.The results show that the water content of the sludge can be reduced to less than 50%after mechanical dewatering and consolidation treatment,and the treated sludge will not encounter water and sludge.The solidified material stabilizes the pollutants by sealing and encapsulating pollutants and changing the form of heavy metals.It has good unconfined compressive strength and can effectively remove harmful substances from the sludge.The content of heavy metals in the solidified sludge leaching solution is lower than the limit value of relevant standards.The seed germination rate of treated sludge is three times higher than that of original sludge under the same conditions.It directly shows that the treated sludge can meet the normal growth needs of plants.It shows that the sludge dewatering and consolidation process studied in this paper is successful and effective in treating river sludge;?5?This process can provide reference for the subsequent reuse of sludge resources and has a demonstration role for the same type of dredged sludge treatment.