Sulfidogenesis in Pretreatment of High-Sulfate Acidic Wastewater Using Anaerobic Sequencing Batch Reactor and Upflow Anaerobic Sludge Blanket Reactor

摘要

In rubber skim block production, use of sulfuric acid is a general practice, which generates acidic wastewatern(pH 2.4 – 0.5) with high chemical oxygen demand (COD) (14,911 – 1,819mg/L) and sulfate (6,506 – 1,038mg/L).nOur work aimed to pretreat this wastewater separately prior to combining with the other wastewaters tonfacilitate efficient anaerobic digesters that follow. Results indicated that sulfate removal efficiency of the an-naerobic sequencing batch reactor (ASBR) pretreating raw rubber skim wastewater (pH 2.43 – 0.50) was onlyn7.25%– 4.01% and gradually improved with increasing influent pH to 45.45%– 3.75% at pH 7. In the second part,nupflow anaerobic sludge blanket (UASB) and ASBR fed with the rubber skim wastewater at pH 7 faced systemnfailure after 97 days of operation. When the influent pH was adjusted to 8, sulfate removals of UASB and ASBRnat 27.37%– 2.55% and 46.58%– 1.98%, respectively, could be sustained. A distinctive ASBR operation that allowsnmixing and settling phases was deemed as key to enable, respectively, better substrate dispersion and retentionnof the poor granulating sulfate-reducing bacteria.