Pilot scale investigation of zinc and sulphate removal from industrial discharges by biological sulphate reduction with molasses as electron donor.
A biological sulphate reduction process, with molasses as an electron donor, was used for the removal of zinc and sulphate from Rayon industrial wastewater. The process involved reduction of sulphate to sulphide under anaerobic conditions. The sulphide-rich effluent was used to remove zinc as zinc sulphide precipitate. The investigation was conducted at pilot scale with real wastewater from the Rayon industry as feed. The effects of sulphate loading rate and temperature of feeding wastewater were evaluated. The experimental results showed that there was no significant difference in sulphide production when the reactor was operated at 50 +/- 2 degrees C and 65 +/- 2 degrees C. Sulphide production was in the range of 500-515 mg L(-1). In addition, an increase in sulphate loading rate from 6.3 +/- 0.7 kg SO4 m(-3) d(-1) to 14.9 +/- 2.4 kg SO4 m(-3) d(-1) resulted in a dramatic decrease in sulphate removal efficiency. Furthermore, zinc sulphide precipitation at pH 7 removed more than 96% of zinc.
Liamleam
Warounsak
W
Environmental Engineering and Management, Asian Institute of Technology, P.O. Box 4, Klongluang, Pathumthani 12120, Thailand.
Oo
Zaw Ko
ZK
Thai
Phan Thong
PT
Annachhatre
Ajit P
AP
D008965:Molasses; D013431:Sulfates / Q000737:chemistry* / Q000302:isolation & purification*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification*; D015032:Zinc / Q000737:chemistry* / Q000302:isolation & purification*
D013431:Sulfates; D014874:Water Pollutants, Chemical; D015032:Zinc