Reaserch On Condensate Characteristics Of Sewage Sludge In Superheated Steam Drying

With the rapid pace of economic curve and the process of urbanization is accelerating in our country,more and more industrial wastewater and urban sewage need to be discharged.While the sewage sludge production also increased.The feature of sludge is high moisture,huge volume and other characteristics,and also contains a large number of pathogenic micro-organisms,heavy metals,other toxic and hazardous substances.If the sludge cannot be harmless and reduced,human living environment is bound to be jeopardized.The traditional sludge treatment and disposal is landfill,composting,incineration.But no matter what method is adopted,the key step of sludge treatment is to reduce the moisture content.Superheated steam drying technology is the development of emerging technologies in recent years,compared with the traditional hot air drying with low energy consumption,good dry quality and security risks and other advantages.During the use of superheated steam drying,the exhaust gas discharges a large amount of water vapor and contaminants,which can be pretreated by means of cooling and condensing.Therefore reducing the volume of exhaust emissions and increasing the discharge efficiency of the subsequent treatment.This paper mainly studies are the use of superheated steam as the drying medium,to analyze the condensate influence on water quality and organic matter analysis at difference drying temperature for continuous.So a set of superheated steam drying test system was set up to collect the condensate at each temperature.The entire experimental system mainly consists of steam generation system,heating system,drying system,condensation system and other devices.According to the experimental requirements,the design of relevant parts and selection of equipment had been completed.The overall structure of test apparatus is compact,safe and reliable.In this paper,the water quality and organic matter of the sludge condensate were analyzed in the process of drying the sludge at 180 ?,220 ? and 260 ?,by measuring the p H value,turbidity,COD value,BOD5 andNH₄⁺-N of the condensate and analyzing chromatography-mass spectrometry of organic matter.The results are summarized as follows:?1?The sludge in the drying process,the collected condensate to form a buffer system so that the PH value of the range of variation in the 5.59 6.39 fluctuations.?2?The COD value of the condensate collected at 180 ? was the smallest under three continuous drying conditions,while the COD value of the condensate at 220 ? was the largest.The results indicating that some of the organic matter in the sludge needed to reach a certain temperature before it was evaporated.With the increase in drying temperature,the biodegradable substances in the condensate have little effect.?3?With the increase of temperature,the concentration of-N in the condensate is increasing,and the turbidity value in the condensate is also increased from 25.2 NTU at 180 ? for drying to 123 NTU at 260 ?.?4?The main components of the organic matter in the condensate are alcohol-based substances at the temperature of 180 ? and 220 ? continuous drying.At 260 ?,the main organic components are aldehyde class.