Research And Applications In Engineering Of Sewage Sludge Treated By Technology Of Thermophilic Aerobic Rapid Fermentation In Seel Cabin

This research was based on the sub-project integration and demonstration of sludgemade as biological carbon soil of Beijing Science and Technology Plan, andDevelopment Fund subject key technology and demonstration research of sewagesludge aerobic fermentation in tunnel cabin organized by China Academy ofMachinery Science technology. In order to search the engineering use of sewagesludge aerobic fermentation of tunnel cabin in a fast and high temperature way, amid-scale research and engineering project was established which aimed at the keyprocess parameters.First, based on the calculation of material, reflux ratio, degree of porosity, freeboard,the analysis of thermodynamics and ventilation system, the mid-scale seal cabin wasestablished. During the test, the changes of comparison was made among threepatterns, including pile temperature, moisture content, value of C/N, pH, pile density,value of ammonia, hydrogen sulfide generation, and humidity up the vent. Andfermentation resource products were evaluated. Then the value of ventilation capacityof fast and seal cabin sewage sludge aerobic fermentation was0.26m3/(min.m3).It was monitored that technology of sewage sludge aerobic fermentation in tunnelcabin would yield stink whose main composition is free ammonia during practicalproduction. In order to reduce the amount of ammonia, it was studied that the law ofnitrogen transformation under different material feed ratio. The studies show that theexperimental group containing42.5%peanut shells whose temperature rise faster andmoisture content reduce sooner and total nitrogen loss fewer.It was indicating thathigh carbon content of additives could ensure ventilation and moisture content controlof the pile and keeping nitrogen content well during fermentation. The biologicalfilter simulation test was processed according on stink escape of open crib type. Thetest showed that the active packing with proportion of fermented products: ceramsite:bark=2:5:3and inert packing with proportion of D50: D25=1:1could operate stablyand the removal rate of ammonia will exceed99%. According to preliminary tests, the design and commissioning of the demonstrationproject was carried out. The variation of pile temperature was studied under differentaeration ways. The results showed that more aeration quantity contributed to keep theappropriate temperature and less aeration quantity contributed to the temperaturerising and keep the higher temperature. The aeration intensity coefficient during thehigh temperature period and temperature dropping period is0.24to0.39m3/（min�'m3）but0.1to0.2m3/（min�'m3）during the temperature rising period. The variationof aerobic composting temperature, water content and organics content were studiedunder different back mixing rate. The odor concentration was monitored during thecomposting. Moreover, the aeration quantity was checked, and the aeration-inducedair model set up by Tecplot. Thanks to the model, the effect of pile temperaturegradient on the induced-air pressure in the composting seal cabin and the variation ofexhaust air moisture under different conditions was studied. The character of thedemonstration project and the devices were illustrated too.