1CE 421/521 Environmental Biotechnology - Fall 2008Biogeochemcial Cycles (C, N, P, & S)• composition of b_______ cell (molar formula:C5H7O2N with P 1/5 of the N requirement) • limiting nutrients are _____ and _____2Organic NNH3NO2-NO3-N2NITROGEN! Atmosphere is _____% nitrogen, yet nitrogen is considered a l__________ n__________! required in p____________Fixation! _____________ metrictons/y compared to2.5x1010 metric tons C/y! c__________________ &few others " non-s_________ –Clostridia" symbiotic –Rhizobium! n_______________ –requires Mg2+ & ATP (15to 20 ATP/N2)Assimilation – NH3 (NH4+) preferred, will use NO3- but has to be reducedto NH4+! C/N ratio is approximately ______:1 for aerobes! C/N ratio is approximately ______:1 for anaerobes! C/N ratio is approximately ______:1 for anaerobes in highly loaded(high rate) system! cell c_____________ is characterized by the empirical formula: C H O N with the P requirement as _________the N requirement(alternatively C60H87O23N12P)! in general cell composition is * 50%* 20%* 10-15%* 8-10%*1-3%* 0.5-1.5%Ammonification: breakdown of o_________ N to inorganic nitrogenex. urea:3proteins: proteins º amino acidsNitrification: two step process1.2.! requires _____________ mg O2/mg NH4+-N convertedto NO3- – NNitrification Kinetics (double M__________, pronounced muh no2!)μμ=+⋅+maxSKSSKSNHSNHOOO4422where μmax = maximum specific g__________ rate, h-1KS = half s________________ coefficient for ammonia, mg/L as NH4-NKO = half saturation coefficient, mg/L as O2Yield = mg b____________ formed/mg a________________ utilized4μμ=+⋅+maxSKSKKINHSNHII44Nitrosomonas Nitrobacterparameter range typical (@ 20°C) range typical (@ 20°C)μmaxKSKOYield0.014 - 0.0920.06 - 5.60.3 - 1.30.04 - 0.130.0321.00.50.10.006 - 0.060.06 - 8.40.3 - 1.30.02 - 0.070.0341.30.680.05Optimum pH for nitrifiers is around 8.0, range 7.5 - 8.5 (higher than for most other biological processes).Nitrifiers are sensitive to • d_________________ o___________________• t_______________• p___• i_______________________where I = concentration of inhibitor, mg/LKI = inhibition coeficient, mg/LEffects of Temperaturederivation of the A_______________ equation kAeRT=−μkkTT2121=−θ()where k1,2 = reaction rate coefficient at temperature T1,2θ = t______________ c_____________________________-theta valuesNitrosomonas NitrobacterμmaxKSkd1.098 - 1.1181.1251.029 - 1.1041.068 - 1.1121.1571.029 - 1.1045μμ=+⋅+−−maxSKSNOKNOSNO333given the following measured data, calculate the theta valueT, °C b, h-1102030400.00370.00950.02290.0372DENITRIFICATION1. A_____________________ nitrate reduction: NO3- º NH4+ nitrate is incorporated into cellmaterial and reduced inside the cell2. D___________________ nitrate reduction (denitrification)NO3- serves as the t____________ e_______________ a_________________ (TEA) in an anoxic(anaerobic) environment nitrate reductase nitrite r. nitric oxide r. nitrous oxide r. NO3- º NO2- º NO º N2O º N2 summarized as:NO3- º NO2- º N2 requires o______________ m________________(example: methanol)6 NO3- + 5CH3OH º 3N2 + 5 CO2 + 7 H2O + 6 OH-calculate COD of methanol:calculate alkalinity:kinetics for denitrification similar to those for heterotrophic aerobic growth6Nitrogen Removal in Wastewater Treatment PlantsTotal Kjeldahl Nitrogen (TKN) = o___________ n___________ + a______________ (measured by digesting sample with sulfuric acid to convert all nitrogen to ammonia)• TKN ~ 35 mg/L in influent• p____________ t____________ removes approximately 15%• additional removal with biomass w______________3 Methods for Nitrogen Removal1. Biological• n_______________• d________________• ANAMMOX: ammonium is the electron donor, nitrite is the TEA NH4+ + NO2- º N2 + 2 H2O2. Chemical/Physical• air s_______________• breakpoint c__________________• ion e_____________________• reverse o___________________Concerns for nitrogen discharge:1. T________________2. D________________ of DO3. E__________________________4. Nitrate in d________________ water – causes methemoglobinemia (blue baby) oxidizeshemoglobin to methemoglobinPHOSPHORUS — limiting n___________________ in algae (at approximately 1/5 the nitrogen requirement) — 15% of population in US discharges to l_________________ — wastewater discharge contains approximately 7- 10 mg/L as P — o__________________ — i______________: orthophosphateRemoval of Phosphorus1. Chemical precipitation:a. traditional p___________________________ reactions Al+3 + PO4-3 º AlPO4 Fe+3 + PO4-3 º FePO4b. as s__________________ (magnesium ammonium phopshate, MAP)7 Mg+2 + NH4+ + PO4-3 º Mg NH4PO42. Enhanced Biological Phosphorus Removal (EBPR) see handoutSULFUR — inorganic: SO4-2 S° H2S— organic: R — O — SO3-2— four key reactions:1. H2S o__________________ — can occur aerobically or anaerobically to elemental sulfur (S°)a. a___________________ : Thiobaccilus thioparus oxidizes S-2 to S° S-2 + ½ O2 + 2H+ º S° + H2Ob. a_______________________: — phototrophs use H2S aselectron donor — filamentous sulfur bacteria oxidize H2S to S° in sulfur granules: Beggiatoa, Thiothrix2. Oxidation of E_______________ Sulfur (Thiobacillus thiooxidans atlow pH) 2S° + 3 O2 + 2 H2O º 2 H2SO43. A_______________________ sulfate reduction: proteolytic bacteriabreakdown organic matter containing sulfur (e.g. amino acids: methionine,cysteine, cystine)4. D_______________________ sulfate reduction: under anaerobicconditions — s_____________ r________________ b_________________ (SRB) SO4-2 + Organics º S-2 + H2O + CO2 S-2 + 2H+ º H2S— Desulvibrio and others— Sulfate is used as a TEA & l_____ m______________ w___________ organics serve as theelectron donors8— Low cell y___________________— P___________________ of SRB depends on COD:S ratio, particularly readily degradable (e.g.,VFA) COD— SRB compete with