The Pilot And Productive Research On Biological Nitrogen And Phosphorus Removal Enhanced By Composite Ferric Enzymatic Activated Sludge

Water pollution and eutrophication have become high-profile global issues, thesituation of water pollution and eutrophication in China are increasingly serious inrecent years, and have become the bottleneck problems that limit a rapid and steadydevelopment of our country’s economy and society. High content of nitrogen andphosphorus nutrient substances in water body is the root cause of eutrophication.Therefore, Effective control of urban sewage nitrogen and phosphorus and othernutrient substances discharge is an important way to solve the eutrophication problem.The existing wastewater biological nitrogen and phosphorus removal technologyhas the problems of lower nitrogen and phosphorus removal efficiency, pooroperational stability and more difficult nitrification in low temperature. The ferricenzymatic activated sludge biological nitrogen and phosphorus removal technology isthrough ferric iron getting involved into microbial biochemical reactions and energymetabolism, strengthen ferric iron participate in the electron transfer and the role ofenzymatic reaction activator to enhance biological nitrogen and phosphorus removalefficiency, provide a new idea for the development of efficient deep nitrogen andphosphorus removal technology. On the base of pre-existing research results in thisstudy, urban sewage as the research object, reveal the principle of ferric enzymaticactivated sludge reaction mechanism of biological nitrogen and phosphorus removalthrough the view points of the pollutions removal rate, nitrification rate and microbialactivity under hypothermic condition. By the productive experiment, analyze theprinciple of ferric enzymatic activated sludge biological nitrogen and phosphorusremoval and determined the best control parameters, through the view points of thepollutions sedimentation performance of activated sludge, removal rate nitrificationrate and the study on process optimization.The research results showed:（1） At low-temperature conditions, microbial activityand treatment ability of ferric enzymatic activated sludge and conventional activatedsludge all suffered the impact with different magnitudes, but the contrast resultshowed that the ferric enzymatic activated sludge had conspicuous resistance temperature changes ability, and its microbial activity and treatment ability weresuperior to those of conventional activated sludge, at the low temperature of13～16℃, compared with the conventional activated sludge, the NH₄⁺-N, PO₄^3--P andCOD removal rate of ferric enzymatic activated sludge were respectively increased by4.84%,21.36%and2.72%. At the low temperature of10～13℃, compared with theconventional activated sludge, the NH₄⁺-N, PO₄^3--P and COD removal rate of ferricenzymatic activated sludge were respectively increased by16.57%,39.79%and5.13%. At the low temperature of7～10℃, compared with the conventional activatedsludge, the NH₄⁺-N, PO₄^3--P and COD removal rate of ferric enzymatic activatedsludge were respectively increased by26.87%,52.13%and6.66%.（2） The specificnitrification rate of the composite iron enzymatic system and traditional system were1.20mgNH₄⁺-N/g MLSS·h and0.68mgNH₄⁺-N/g MLSS·h, which was43.33%higherthan that of traditional system; At low-temperature conditions of9.5～11.6℃。（3）When the ferric enzymatic activated sludge was gradually forming, its sludgeconcentration was obviously improved, formed large and dense flocculent structure,and enhanced the sedimentation performance of activated sludge. Compared withbefore the ferric enzymatic activated sludge was formed the COD, SS, TN and TPremoval rate of ferric enzymatic activated sludge were respectively increased by83.95%,87.20%,39.00%and46.38%.（4） After the ferric enzymatic activated sludgewas formed, determined the best control parameters through the effect of biologicalnitrogen and phosphorus removal in different conditions of DO, reflux ratio, feedmode, external carbon addition. The ferric enzymatic activated sludge has stableeffect and higher nitrogen and phosphorus removal efficiency in the best controlparameters condition, he COD,TN, NH₄⁺-N and TP removal rate of ferric enzymaticactivated sludge respectively90.9%,75.6%,99.3%and91.0%. The effluent qualitysatisfy the primary standard A of the “Cities Sewage treatment plant Pollutantdischarge Standard”.