西安建筑科技大学：《水资源利用与保护》参考资料_Wastewater as a resource_Wastewater characteristics

Wastewater characteristics related to treatment processes

Wastewater characteristics related to treatment processes

Criteria to describe the characteristics Physical(SS, VSS, TSS..) Chemical (pH, Heayy metals P Biochemical (COD, BOD, TOC..) e Hygienic(Strain No of E. Coli,

Criteria to describe the characteristics Physical (SS, VSS, TSS…… ) Chemical (pH, Heavy metals…… ) Biochemical (COD, BOD, TOC…… ) Hygienic (Strain No of E. Coli, …… )

Understanding well the characteristics of wastewater to be treated is the first step towards a successful process design

Understanding well the characteristics of wastewater to be treated is the first step towards a successful process design

Constitution of influent cod Influent coD Biodegradable Unbiodegradable Biomass CoD COD COD Readily Slowly Soluble Particulate Biodegradable Biodegradable Unbiodegradable Unbiodegradable COD (SS) COD (XS COD(SD COD(X)

Influent COD Unbiodegradable COD Biodegradable COD Readily Biodegradable COD (SS) Biomass COD Slowly Biodegradable COD (XS) Soluble Unbiodegradable COD (SI) Particulate Unbiodegradable COD (XI) Constitution of Influent COD

Carbonaceous compounds behavior in biological activated sludge process e S, will pass through the treatment process and be discharged with the effluent X is enmeshed in the activated sludge. The mass of X entering the system will equal the mass leaving the system via activated sludge wasting. Thus, XI has the principal effect of increasing the mixed liquor suspended solid(Mlss)concentration e Ss is taken up by activated sludge in a matter of minutes and metabolized, giving rise to a high unit rate of oxygen demand for synthesis e Xs must first be absorbed onto the microorganisms, and broken down to simple chemical units(ss) by extracellular enzymes before finally being metabolized by the microorganisms 05/10/2002

Carbonaceous compounds behavior in biological activated sludge process SI will pass through the treatment process and be discharged with the effluent. XI is enmeshed in the activated sludge. The mass of XI entering the system will equal the mass leaving the system via activated sludge wasting. Thus, XI has the principal effect of increasing the mixed liquor suspended solid (MLSS) concentration. S S is taken up by activated sludge in a matter of minutes and metabolized, giving rise to a high unit rate of oxygen demand for synthesis. X S must first be absorbed onto the microorganisms, and broken down to simple chemical units (S S) by extracellular enzymes before finally being metabolized by the microorganisms. 05/10/2002

COD flow in activated sludge process Growth Nitrifier Decay Heterotrophs ydrolysis Growth 05/10/2002

XA SNH So SNO XS XP XH Decay Decay So Growth Ss Hydrolysis Growth Nitrifiers Heterotrophs COD flow in activated sludge process 05/10/2002

Constitution of influent Nitrogen Influent Nitrogen Inorganic Nitrogen Organic Nitrogen Free and Saline Nitrite Nitrate Soluble Organic Particulate Organic Nitrogen(SNH Nitrogen(SNo) Nitrogen(SND) Nitrogen(XND)

Constitution of influent Nitrogen Influent Nitrogen Inorganic Nitrogen Organic Nitrogen Free and Saline Nitrogen(SNH ) Nitrite & Nitrate Nitrogen(SNO ) Soluble Organic Nitrogen(SND ) Particulate Organic Nitrogen(XND )

Nitrogen flow in activated sludge process Particulate organic nitrogen (XND Hydrolysis Soluble organic nitrogen (SND) Ammonification Ammonia and ammonium Assimilation Organic nitrogen nitrogen (Bacterial cell) Nitrified Nitrite and nitrate Denitrification Nitrogen gas(N2) nitrogen(SNo)

Particulate organic nitrogen (XND) Soluble organic nitrogen (SND) Ammonia and ammonium nitrogen (SNH) Nitrite and nitrate nitrogen (SNO) Hydrolysis Ammonification Nitrification Nitrogen gas (N2 Denitrification ) Assimilation Organic nitrogen (Bacterial cell) Lysis and decay Nitrogen flow in activated sludge process

Nitrogen compounds behavior in biological activated sludge process SNH can be used directly as a nutrient for bacteria growth, or nitrified into SNo by autotrophic bacteria; P SND must be firstly decomposed into SNH (Ammonification), then participates in the SNH material flow XND must be firstly hydrolyzed into SND, then participates in the snd material flow 05/10/2002

Nitrogen compounds behavior in biological activated sludge process SNH can be used directly as a nutrient for bacteria growth, or nitrified into SNO by autotrophic bacteria; SND must be firstly decomposed into SNH (Ammonification), then participates in the SNH material flow; XND must be firstly hydrolyzed into SND, then participates in the SND material flow. 05/10/2002

Characteristics of sewage compositio in Xi'an COD- COD/ BODS Ss S, Xs X, SNH SNoXND BEI SHIQIAOI 649 51314 2.7 230.63 BEI SHIQLAO*62651.41320483.41405 6262.1715.30.5618.3 DIAN ZICUN*4005720338.918.229013402.725 20.1 Monthly average dada ** Data obtained by the university *** Data obtained by the university 05/10/2002

CODT CODf BOD5 Ss SI Xs XI XBH SND SNH SNO XND BEI SHIQIAO* 649 51 314 2.7 23 0.63 BEI SHIQIAO** 626 51.41 320 48 3.41 405 107 62.6 2.17 15.3 0.56 18.3 DIAN ZICUN** 400 57 203 38.9 18.2 290 13 40 2.7 25 0 20.1 05/10/2002 Characteristics of sewage composition in Xi’an * Monthly average dada ** Data obtained by the University *** Data obtained by the University