Energy consumption by forward osmosis treatment of landfill leachate for water recovery. (May 2017)

• Record Type: Journal Article
• Authors: Iskander, Syeed Md; Zou, Shiqiang; Brazil, Brian; Novak, John T.; He, Zhen
• Is Part Of: Waste management. Volume 63(2017)
• Page Start: 284
• Page End: 291
• Publication Date: 2017-05
• Subjects: Forward osmosis -- Landfill leachate -- Energy consumption -- Recirculation -- Water recovery; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2017.03.026
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: Energy consumption by FO treatment of landfill leachate is investigated. A higher recirculation rate leads to higher energy consumption. A higher initial draw concentration results in lower energy consumption. The highest energy consumption is 0.273 ± 0.033 kW h m −3 . The leachate with lower contaminant concentrations will require less energy. Abstract: 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 ± 0.033 kW h m −3 with the recirculation rate of 110 mL min −1 and 1-M draw concentration, while the lowest of 0.005 ± 0.000 kW h m −3 was obtained with 30 mL min −1 recirculation 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.