# Chapter 5 - CSTR

 The flashcards below were created by user Chelsear11 on FreezingBlue Flashcards. Assumptions aerobic heterotrophsCOD is limiting nutrient Hydraulic residence time= V/F c mean cell residence timeSRTVX/FwXw 4 mass balance equations needed Ss, XB,H, XD, Oxygen iO/XB,V 1.42 g COD/g VSS iO/XB,T 1.20 g COD/g TSS Mass Balance on Biomass Equation H= (1/c) + bH Monod equation Mass balance on soluble substrate tells us: The amount of biomass will increase if SSO increasessmall volume bioreactor has higher concentration of active biomass, although total mass is same as large rxras flow is increased with constant SRT, biomass increases fA active fraction of biomassConcentration of active biomass divided by total biomass concentrationXBH / Xtotal Active fraction of biomass ______ as SRT increases. Why? decreasesBuildup of biomass debris in the bioreactor Observed yield definition Actual net biomass formed per unit mass of substrate destroyedtakes into consideration loss from decay Larger SRT _______ observed yield. Why? decreases. greater opportunity of biomass decay and greater need for maintenance energy, leaving less energy for new cell synthesis Wtotal total biomass wastage rateFWXtotal Wtotal depends on these 3 things: SRTflowrateconcentration of substrate in rxr As SRT increases, biomass wastage rate ________. Why? increases at first and then decreasesincreased importance of decay, and decrease in excess biomassmore and more active biomass is oxidized and converted to debris and less must be disposed of COD balance states that the amount of oxygen that must be supplied to a bioreactor must equal ____________. The total COD in minus the total COD out, including COD of biomass and biomass debris. Phosphorus requirement is about ______ the nitrogen requirement 1/5 As SRT increases, Ss __________. Why? decreasesgrowth can be established and substrate removal increases. As SRT increases, total biomass (g) _________. increases. As SRT increases, oxygen demand ____________. Why? sharply increases, then steadily increases.little oxygen required at short SRT because substrate removal isn't completeas SRT increases, to the point where removal is complete, all oxygen is associated with biomass growthIncreasing further means more decay and increase in oxygen requirment is associated with decay SI Soluble non biodegradable organic matter. Influent concentration = effluent concentration XI Inert suspended solidsMass leaving = mass entering, but some get stuck inside and spend longer. XM,T Mixed liquor suspended solids on TSS basisIncludes acive biomass and biomass debrisUsed when influent has inerts The presence of active biomass in the influent _________ specific growth rate relative to SRT. reducesIf biomass is present in the influent the biomass in the reactor does not have to grow as fast to maintain itself as it does when the influent contains no biomass. If 2 reactors have the same HRT and SRT but one receives active biomass in the influent, it will produce an effluent with ________ substrate concentration Lower. AuthorChelsear11 ID149105 Card SetChapter 5 - CSTR DescriptionSRT, biomass Updated2012-04-21T22:23:55Z Show Answers