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Civil and Environmental Engineering

California Polytechnic State University, San Luis Obispo

Series

2009

Wastewater treatment

Articles 1 - 3 of 3

Full-Text Articles in Engineering

Algae Grown On Dairy And Municipal Wastewater For Simultaneous Nutrient Removal And Lipid Production For Biofuel Feedstock, Ian Woertz, A. Feffer, Tryg Lundquist, Yarrow Nelson Nov 2009

Algae Grown On Dairy And Municipal Wastewater For Simultaneous Nutrient Removal And Lipid Production For Biofuel Feedstock, Ian Woertz, A. Feffer, Tryg Lundquist, Yarrow Nelson

Civil and Environmental Engineering

Algae grown on wastewater media are a potential source of low-cost lipids for production of liquid biofuels. This study investigated lipid productivity and nutrient removal by green algae grown during treatment of dairy farm and municipal wastewaters supplemented with CO2. Dairy wastewater was treated outdoors in bench-scale batch cultures. The lipid content of the volatile solids peaked at Day 6, during exponential growth, and declined thereafter. Peak lipid content ranged from 14–29%, depending on wastewater concentration. Maximum lipid productivity also peaked at Day 6 of batch growth, with a volumetric productivity of 17 mg/day/L of reactor and an …


Nutrient Removal & Greenhouse Gas Abatement With Co2 Supplemented Algal High Rate Ponds, Ian Woertz, Laura Fulton, Tryg Lundquist Oct 2009

Nutrient Removal & Greenhouse Gas Abatement With Co2 Supplemented Algal High Rate Ponds, Ian Woertz, Laura Fulton, Tryg Lundquist

Civil and Environmental Engineering

High rate algae ponds fed clarified domestic wastewater and CO2-rich flue gas are expected to remove nutrients to concentrations similar to those achieved in mechanical treatment technologies, such as activated sludge. However, the energy intensity of wastewater treatment with CO2-supplemented high rate ponds (HRPs) would be less than that of mechanical treatments. In conjunction with anaerobic digestion of algal biomass and co-substrates, the algae-based system would produce a substantial excess of electricity. Greenhouse gas abatement from such CO2-HRP/digestion systems would stem mainly from energy conservation and the offset of fossil fuel electricity with biogas-derived …


Biogas Production From Algae Biomass Harvested At Wastewater Treatment Ponds, Michael Salerno, Yakup Nurdogan, Tryg J. Lundquist Oct 2009

Biogas Production From Algae Biomass Harvested At Wastewater Treatment Ponds, Michael Salerno, Yakup Nurdogan, Tryg J. Lundquist

Civil and Environmental Engineering

Waste-grown microalgae are a potentially important biomass for biofuel production. However, most of the 7,000 wastewater treatment ponds systems in the US do not use algae harvesting. Those that do, typically return the biomass to the ponds, where it decomposes on the pond floor, releasing methane to the atmosphere and degrading water quality. Instead, the algae biomass could be processed in anaerobic digesters. Algae typically yield less methane than wastewater sludge (~0.3 vs. 0.40 L CH4/g volatile solids introduced). Ammonia toxicity and recalcitrant cell walls are commonly cited causes of the lower yields. Ammonia toxicity might be counteracted by co-digesting …