Department of Civil and Environmental Engineering, University of Idaho, Moscow, ID, USA.
Water Environ Res. 2018 Jul 1;90(7):659-671. doi: 10.2175/106143017X15131012153130.
Enhanced biological phosphorus removal (EBPR) is an engineered water resource recovery facility (WRRF) process configuration that can produce effluent P < 0.5 mg/L. To consistently achieve low effluent P concentrations, EBPR requires volatile fatty acids (VFAs) to induce requisite biochemical reactions. Moreover, returned activated sludge (RAS) nitrate concentrations must be minimized. Returned activated sludge fermentation can potentially address process needs. However, research detailed herein highlights concerns with RAS fermentation integrated with EBPR. Under 2 and 4 hours of RAS fermentation periods, no consequential VFA production was observed; similar results were observed in batch tests with RAS from a full-scale EBPR WRRF. More critically, EBPR performance was poor, with average effluent concentrations of 1.0 to 2.4 mg/L. Furthermore, the glycogen accumulating organism (GAO) fraction under RAS fermentation was 4.3 to 8.7 times higher than in a conventional EBPR mixed microbial consortium (MMC). Integrated RAS fermentation-EBPR only performed well under "high" RAS nitrate; thus, should RAS fermentation be implemented, careful control to prevent anaerobic conditions in the fermentation zone is required.
强化生物除磷（EBPR）是一种经过工程设计的水资源回收设施（WRRF）工艺配置，可以生产出磷含量 < 0.5 mg/L 的出水。为了始终如一地实现低磷出水浓度，EBPR 需要挥发性脂肪酸（VFAs）来引发必要的生化反应。此外，必须将回流活性污泥（RAS）中的硝酸盐浓度降至最低。回流活性污泥发酵有可能解决工艺需求。然而，本文详细介绍的研究强调了将 RAS 发酵与 EBPR 集成的相关问题。在 2 小时和 4 小时的 RAS 发酵期内，没有观察到明显的 VFA 生成；在全规模 EBPR WRRF 的 RAS 批处理测试中也观察到了类似的结果。更关键的是，EBPR 的性能不佳，出水浓度平均为 1.0 至 2.4 mg/L。此外，在 RAS 发酵期间，糖原积累菌（GAO）的比例比传统 EBPR 混合微生物群落（MMC）高 4.3 至 8.7 倍。只有在“高”RAS 硝酸盐条件下，集成的 RAS 发酵-EBPR 才能良好运行；因此，如果要实施 RAS 发酵，则需要进行仔细的控制，以防止发酵区出现厌氧条件。
