School of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China.
Water Sci Technol. 2009;60(12):3275-84. doi: 10.2166/wst.2009.737.
In this study, an immediate aerobic-anaerobic-aerobic (O/A/O) biological process was established for the treatment of black liquor of cotton pulp and was tested by both laboratory-scale batch experiment and pilot-scale continuous experiment. The effects of the hydraulic retention time (HRT) were studied, as were the alkaliphilic bacteria number, the culturing temperature and the concentration of black liquor on COD (chemical oxygen demand) removal. The total COD (COD(tot)) removal rate of the novel O/A/O process, for a black liquor with influent COD(tot) over 8,000 mg/L and pH above 12.8, was 68.7+/-4% which is similar with that of the traditional acidic-anaerobic-aerobic process (64.9+/-3%). The first aerobic stage based on alkaliphilic bacteria was the crucial part of the process, which was responsible for decreasing the influent pH from above 12 to an acceptable level for the following treatment unit. The average generation time of the alkaliphilic bacteria in the black liquor was about 36 minutes at 40 degrees C in a batch aerobic activated sludge system. The efficiency of the first aerobic stage was affected greatly by the temperature. The COD(tot) removal at 55 degrees C was much lower in comparison with the COD(tot) removal at 45 degrees C or 50 degrees C. Both the laboratory-scale batch experiments and the pilot-scale continuous experiment showed that the COD(tot) removal rate could reach about 65% for original black liquor with a pH of about 13.0 and a COD of 18,000-22,000 mg/L by the immediate O/A/O process. The first aerobic stage gave an average COD(tot) removal of 45.5% at 35 degrees C (HRT = 72 h) at a volume loading rate of 3.4 kg COD m(-3) d(-1).
在这项研究中，建立了一种立即进行好氧-厌氧-好氧（O/A/O）生物处理工艺，用于处理棉浆黑液，并通过实验室规模的批量实验和中试规模的连续实验进行了测试。研究了水力停留时间（HRT）的影响，以及嗜碱菌数量、培养温度和黑液浓度对 COD（化学需氧量）去除的影响。新型 O/A/O 工艺对 COD（tot）进水超过 8000mg/L、pH 值高于 12.8 的黑液的总 COD（COD（tot））去除率为 68.7+/-4%，与传统酸性-厌氧-好氧工艺（64.9+/-3%）相似。基于嗜碱菌的第一好氧阶段是该工艺的关键部分，负责将进水 pH 值从高于 12 降低到后续处理单元可接受的水平。在 40°C 的批式好氧活性污泥系统中，嗜碱菌的平均世代时间约为 36 分钟。第一好氧阶段的效率受温度影响很大。55°C 时的 COD（tot）去除率远低于 45°C 或 50°C 时的 COD（tot）去除率。实验室规模的批量实验和中试规模的连续实验均表明，立即 O/A/O 工艺可将 pH 值约为 13.0、COD 值为 18000-22000mg/L 的原始黑液的 COD（tot）去除率提高到约 65%。在 35°C（HRT=72h）下，体积负荷率为 3.4kg COD m(-3) d(-1)时，第一好氧阶段的平均 COD（tot）去除率为 45.5%。
