改进的高温微好氧消化工艺处理市政污泥研究

Improved Thermophilic Micro-aerobic Digestion Process for Treatment of Sewage Sludge

对单级自热式高温微好氧消化工艺进行改进,采用先短期(4 d)中温厌氧消化再高温微好氧消化的工艺处理市政污泥,分析了对污泥的稳定化效果。至第14天该工艺对挥发性有机物(VSS)的去除率为40%,达到美国环保局503条款和我国《城镇污水处理厂污染物排放标准》(GB 18918—2002)中稳定化的要求,且与高温微好氧消化达到污泥稳定的时间相同。其ORP与高温微好氧消化工艺的类似,初期呈现厌氧水解状态,处于-50 mV以下,随后逐渐上升至100 mV左右。中温厌氧/高温微好氧消化系统中产生挥发性有机酸(VFA),污泥上清液中的VFA在第11天达到最高为269 mg/L。此外,污泥上清液中的总有机碳(TOC)在第8天达到最高为5 040 mg/L。污泥消化至第30天TOC仍高达1 980 mg/L,表明污泥中存在一些难以去除的可溶性有机物。

The single-stage autothermal thermophilic micro-aerobic digestion （ATMD） process was improved to treat sewage sludge by 4-day mesophilic anaerobic digestion followed by ATMD （short for MAD-ATMD）. The stabilization of sludge was analyzed. The volatile suspended solid （VSS） removal rate of 40% was stabilized by the MAD-ATMD process on the 14th day, meeting the standards of Class A issued by US EPA, Item 503, and the Discharge Standard of Pollutants for Municipal Wastewater Treat- ment Plant （GB 18918 -2002）, same as that achieved by the ATMD process. The oxidization-reduction potential （ORP） of the sludge in the MAD-ATMD process system, which was similar to that in the ATAD process, was below -50 mV due to the initial hydrolysis reaction, and then gradually increased to about 100 mV. The volatile fatty acids （VFAs） and total organic carbon （TOC） produced in the MAD-ATMD process system could reach the highest values of 269 mg/L on the llth day and 5 040 mg/L on the 8th day, respectively. While TOC still remained at 1 980 mg/L through the digestion time of 30 d, which showed that some soluble VFAs could not be removed during the 30 d digestion.