The Experimental Study of Weight Reduced Wastewater Treatment by Two-stage Upflow Anaerobic Filter

Abstract

This research was done for experimental study to treat weight reduced wastewater (WR). WR wastewatercontained a lot of aromatic compounds (COD 66,000 mg/L) which were oligomers of terephthalate and hardlyto be degraded by anaerobic microorganisms. Therefore, chemical precipitation was selected to pretreat thiswastewater to remove most organic substances, then followed by two stage upflow anaerobic filter treatment. Theholding volume of acidogenic and methanogenic fermenters were 1.8 L and 6.2 L with hydraulic retention time(HRT) 0.9 day and 3.1 days, respectively.

From the experimental results, the appropriate pH for chemical precipitation by sulfuric acid solutionis pH 4 which could remove 62 %COD. Furthermore, biological treatment at organic loading 0.21 0.26 0.310.36 and 0.52 kg COD /m3/ day were concluded that 0.31 kg COD/m3/day was the optimum COD loading foracidogenic and methanogenic bacteria. Acidogenic bacteria could produce a good quantity of Volatile Fatty Acid(VFA) in acid fermenter. (VFA 354 mg/L as CH3COOH) At this loading, alkalinity, pH and VFA /alkalinity ratioin methane fermenter were optimized to methanogenic bacteria which has 85% VFA reduced rate. Total organicremoval efficiency of two-stage upflow anaerobic filter was 58%. At the higher organic loading, organic removalefficiency in both acid and methane fermenters were decreased due to the effect of high sulfate concentrationwhich inhibited the acidogenic and methanogenic bacteria.