Yang P Y, Cao K, Kim S J
Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu 96822, USA.
Water Environ Res. 2002 May-Jun;74(3):226-34. doi: 10.2175/106143002x139947.
An entrapped mixed microbial cell (EMMC) process was investigated for simultaneous removal of carbon and nitrogen from a synthetic wastewater in a single bioreactor. The influent had a soluble chemical oxygen demand (SCOD)/nitrogen ratio varying from 4 to 15 and an alkalinity of 140 and 230 mg/L as calcium carbonate. An alternating schedule of intermittent aeration was used for two sizes of carriers: 10 x 10 x 10 mm3 and 20 x 20 x 20 mm3. The medium carrier (10 x 10 x 10 mm3) was found to achieve higher removals of nitrogen, chemical oxygen demand, and 5-day biochemical oxygen demand of 92, 95, and 97%, respectively. These higher removal rates occurred at a 12-hour hydraulic retention time (HRT), an aeration/ nonaeration ratio of 0.5:2 hours, and an SCOD/nitrogen ratio of 15 in the influent. Influent alkalinity concentrations of 140 and 230 mg/L as calcium carbonate were found to have minimum effect on the removal of carbon and nitrogen. However, the oxidation-reduction potential, ranging from -100 to 400 mV (during air-off period), provides better nitrogen removal efficiency to maintain the total nitrogen (nitrate, nitrite, and ammonium) less than 10 mg/L when an SCOD/nitrogen ratio of 10 or 15 is maintained in the influent. Nitrogen removal efficiency increased with increasing ratios of SCOD/nitrogen in the influent (i.e., SCOD/ nitrogen ratio of 15 > 10 > 7 > 4.0). The results of actual wastewater operation based on a study of synthetic wastewater show that organics removal efficiencies (94.6 and 94.2%) and nitrogen removal efficiencies (61.0 and 60.9%) are similar for reactors packed with medium and large carriers, respectively, when they are operated with a 9-hour HRT, an air on/air off ratio of 1 hour:2 hours and an SCOD/nitrogen ratio of 4.6.
研究了一种截留混合微生物细胞（EMMC）工艺，用于在单个生物反应器中同时去除合成废水中的碳和氮。进水的可溶性化学需氧量（SCOD）/氮比在4至15之间，以碳酸钙计的碱度为140和230mg/L。对两种尺寸的载体采用交替间歇曝气方案：10×10×10mm³和20×20×20mm³。发现中等尺寸载体（10×10×10mm³）对氮、化学需氧量和五日生化需氧量的去除率更高，分别为92%、95%和97%。这些较高的去除率出现在水力停留时间（HRT）为12小时、曝气/非曝气比为0.5:2小时且进水SCOD/氮比为15的情况下。发现以碳酸钙计的进水碱度浓度为140和230mg/L时，对碳和氮的去除影响最小。然而，当进水保持SCOD/氮比为10或15时，氧化还原电位在-100至400mV（在停止曝气期间）范围内，能提供更好的氮去除效率，使总氮（硝酸盐、亚硝酸盐和铵）保持在10mg/L以下。进水SCOD/氮比增加时，氮去除效率提高（即进水SCOD/氮比为15＞10＞7＞4.0）。基于合成废水研究的实际废水运行结果表明，当以9小时HRT、曝气/停止曝气比为1小时:2小时且SCOD/氮比为4.6运行时，填充中等尺寸和大尺寸载体的反应器的有机物去除效率（分别为）94.6%和94.2%，氮去除效率（分别为）61.0%和60.9%相似。
