Research Of Residual Sludge With High Temperature Anaerobic Digestion In Lanzhou Area

This thesis conducts a analytical research of excess sludge during the process ofthermophilic anaerobic digestion, in which the index of total nitrogen, ammonia, totalphosphorus, organic materials, available K, arsenic and chromium are testified before andafter, or even during the digestion process. The preliminary study explores the influence oftotal nitrogen, ammonia, total phosphorus, organic materials, available K, arsenic andchromium in excess sludge during high temperature anaerobic digestion process. In addition,further comparison with the standard of the sludge in urban sewage treatment plant, sludgedisposal, landscaping (GB/T23486-2009) is explored and arrives at the followingconclusions.(1) The total nitrogen content of the excess sludge is decreased to48.78%during theprocess of thermophilic anaerobic digestion, with19.87g/kg of the total content afterdigestion; while the level of ammonia is increased to×10~5.59%with215mg/kg of the wholecontent after disgestion; available K amounts to93.44%with1.18g/kg post-digestive content;organic materials reduces by17.996%with257g/kg of post-digestion; total phosphorus addsup by16.667percent with14g/kg of post-disgestion; the content of arsenic lowered to52.241percent along with9.015mg/kg after digestion; and the level of chromium drops to42.132%together with79.031mg/kg after digestion.(2) The post-digestive sludge can be suitable for the cultivation of garden greeningmedium soil or soil improvement materials by high temperature anaerobic digestion. The totalnutrient in sewage sludge refers to the mass sum of the total nitrogen, total phosphorus, totalpotassium. This thesis only tests the available potassium content, therefore, the results containmass sum of the total nitrogen, total phosphorus, total potassium. However, it still fails tomeet the standard of the sludge in urban sewage treatment plant, sludge disposal as well aslandscaping (GB/T23486-2009)(3) Due to the fact that dynamic capacity Q is more suitable to the reality of nature thanstatic capacity Q0.Thus, dynamic capacity Q is chosen to compute the maximum annualutilization on sludge of high temperature anaerobic digestion. In Lan Zhou, choromiun extertthe huge influence on the maximum employment of sludge. This paper conducts a study ontwo kinds of soil in Lan Zhou, that is, great soil and acrisol. The research result shows that theutility quantity of acrisol is slightly larger than great soil. When confined to50years ofutilization, the great soil reaches6.3488×10~5kg/(hm~2·a) per year and acrisol arrives at6.3496×10~5kg/(hm~2·a) every year; when the environment expands to75years, the annualemployment of great soil sludge is6.3282×10~5kg/(hm~2·a) and the annual acrisol sludge is6.3292×10~5kg/(hm~2·a)；when environment reaches100years, the annual utilization of sludge amounts to6.3267×10~5kg/(hm~2·a) and the annual utility of acrisol is6.3267×10~5kg/(hm~2·a).