Energy consumption by forward osmosis treatment of landfill leachate for water recovery.
Forward osmosis (FO) is an alternative approach for treating landfill leachate with potential advantages of reducing leachate volume and recovering high quality water for direct discharge or reuse. However, energy consumption by FO treatment of leachate has not been examined before. Herein, the operational factors such as recirculation rates and draw concentrations were studied for their effects on the quantified energy consumption by an FO system treating actual leachate collected from two different landfills. It was found that the energy consumption increased with a higher recirculation rate and decreased with a higher draw concentration, and higher water recovery tended to reduce energy consumption. The highest energy consumption was 0.276±0.033kWhm-3with the recirculation rate of 110mLmin-1and 1-M draw concentration, while the lowest of 0.005±0.000kWhm-3was obtained with 30mLmin-1recirculation and 3-M draw concentration. The leachate with lower concentrations of the contaminants had a much lower requirement for energy, benefited from its higher water recovery. Osmotic backwashing appeared to be more effective for removing foulants, but precise understanding of membrane fouling and its controlling methods will need a long-term study. The results of this work have implied that FO treatment of leachate could be energy efficient, especially with the use of a suitable draw solute that can be regenerated in an energy efficient way and/or through combination with other treatment technologies that can reduce contaminant concentrations before FO treatment, which warrants further investigation.
Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Syeed Md
SM
Iskander
Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Shiqiang
S
Zou
Waste Management, Gaithersburg, MD 20882, USA.
Brian
B
Brazil
Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
John T
JT
Novak
Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. Electronic address: zhenhe@vt.edu.
Zhen
Z
He
D009995:Osmosis; D064091:Waste Disposal Facilities; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000032:analysis*; D060753:Water Quality
D062065:Wastewater; D014874:Water Pollutants, Chemical
Energy consumption; Forward osmosis; Landfill leachate; Recirculation; Water recovery