Goel R, Yasui H, Shibayama C
Kurita Water Industries, Research and Development Center, 7-1, Wakamiya, Morinosato, Atsugi, Kanagawa, Japan 243-0124.
Water Sci Technol. 2003;47(12):261-7.
To maximize the sludge degradation efficiencies during anaerobic digestion, pre-ozonation of raw activated sludge and/or post-ozonation of anaerobically digested sludge were used in combination with a reactor operated without solid withdrawal (closed loop operation scheme). Out of the two studied configurations, the configuration with the post-ozonation of digested sludge was found to be superior with respect to degradation efficiencies, lower accumulation of total volatile solid (TVS) and lower required ozone dose. The TVS concentration in the reactor with post ozonation was found to be around 26 +/- 2 g/l at an average TVS loading of 0.6 kgTVS/m3 x d. The maximum TVS removal efficiencies were observed to be around 85% with average specific gas recoveries of 0.36 l CH4/gTVS fed. The ozone dose of 3% on the recycle sludge was found to be sufficient as it was observed that the higher ozone doses of 6% neither improved the TVS reduction efficiency nor reduced the TVS concentration in the reactor. The ozone requirements were estimated at around 0.054 gO3/gTVS removed or 0.045 gO3/gTVS fed. The soluble COD concentrations from the reactor ranged from 500-875 mg/l with negligibly small amount of VFA. The average COD in the centrate of the digested sludge was around 3000 mg/l suggesting the presence of colloidal COD in the reactors.
为了在厌氧消化过程中使污泥降解效率最大化，将原生活性污泥的预臭氧化和/或厌氧消化污泥的后臭氧化与不进行固体排放的反应器（闭环运行方案）结合使用。在研究的两种配置中，发现消化污泥后臭氧化的配置在降解效率、较低的总挥发性固体（TVS）积累和较低的所需臭氧剂量方面表现更优。在后臭氧化的反应器中，在平均TVS负荷为0.6 kgTVS/m³·d的情况下，TVS浓度约为26±2 g/l。观察到最大TVS去除效率约为85%，平均比气体回收率为0.36 l CH₄/g进料TVS。发现对循环污泥投加3%的臭氧剂量就足够了，因为观察到6%的更高臭氧剂量既没有提高TVS降低效率，也没有降低反应器中的TVS浓度。估计臭氧需求量约为0.054 gO₃/g去除的TVS或0.045 gO₃/g进料的TVS。反应器中可溶性化学需氧量（COD）浓度范围为500 - 875 mg/l，挥发性脂肪酸（VFA）含量极少。消化污泥的滤液中平均COD约为3000 mg/l，这表明反应器中存在胶体COD。
