1ESM 219Wastewater MicrobiologyWastewater Microbiology•Microbes are the catalysts in biological treatment, converting dissolved nutrients to biomass which is then separately disposed of•Harmful microbes are killed by disinfection prior to releasing the final effluent•Solids may be digested by anaerobic microbes, producing energy rich gasWastewater constituentsMajor classes– Suspended solids (TSS, VSS, etc.)– Biodegradable organics (BOD, COD– Pathogens (bacteria, viruses, protozoa, etc.)– Nutrients (N, P, etc.)– Priority pollutants (EPA designated toxics)– Organics that don’t biodegrade (refractory)– Heavy metals (Cd, Zn, Pb, Hg, Cu)– Ions (pH; contribute to TDS e.g. Ca2+, Na+, SO4-2)– Temperature– toxicityBiochemical Oxygen Demand (BOD)•Establishes biological “strength” based on oxygen uptake by microbes during aerobic metabolism of organics in waste•5-day (BOD5) and 20-day (BOD20)•Carbonaceous (CBOD)•Nitrogenous (NBOD)•Ultimate (UBOD)BOD•Standardized•Need:IncubatorBottlesDO meterDilution waterSeed (opt.)Expressed in mg/L
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