Energy Requirement in Water PurificationTheoretical minimum energy requirementE=πVΠ=osmotic pressure=nCRTC is concentration (Molarity)R: 8.31 J/molK=.0821 (L*atm/K*mol)T: Temperature in Kelvinn: Number of ions in waterSomething that does not dissociate into ions, counts as 1 particleSeawater ExampleContains NaCl at about 33g/L= .56MN=2π=.56*.0821*2*298=27.6atmE=…Pa*m3  Joules, then convert to kWhMinimum Energy Requirement o Wastewater treatment50mg/L NaCl2g (COD/m^2) organicπ1=.04atmπ2=1*4*10^-6 *.0821 298= 1*10^-5atmE=.04*V~.001kWhChemical Oxygen Demand (COD) of wastewaterTypically 14.7 kJ/g CODEnergy from COD = 14.7kJ/g * 2g/m3=29.4kJ/m^3=.008kWhE from COD> E required for wastewater treatmentEnergy NeutralWastewater treatment is much more sustainableEnergy and Water 05/03/2012Energy Requirement in Water Purification- Theoretical minimum energy requiremento E=πVo Π=osmotic pressure=nCRT C is concentration (Molarity) R: 8.31 J/molK=.0821 (L*atm/K*mol) T: Temperature in Kelvin n: Number of ions in water Something that does not dissociate into ions, counts as 1 particleo Seawater Example Contains NaCl at about 33g/L= .56M N=2 π=.56*.0821*2*298=27.6atm E=…Pa*m3  Joules, then convert to kWh- Minimum Energy Requirement o Wastewater treatmento 50mg/L NaClo 2g (COD/m^2) organico π1=.04atmo π2=1*4*10^-6 *.0821 298= 1*10^-5atmo E=.04*V~.001kWh- Chemical Oxygen Demand (COD) of wastewatero Typically 14.7 kJ/g CODo Energy from COD = 14.7kJ/g * 2g/m3=29.4kJ/m^3=.008kWho E from COD> E required for wastewater treatment Energy Neutral- Wastewater treatment is much more