限氧废水处理系统的再启动与ANAMMOX功能恢复

Restart-up of an oxygen limitation wastewater treatment process for the recovery of ANAMMOX

摘要:

为解决低碳氮比有机废水生物脱氮的难题,经济高效的厌氧氨氧化（ANAMMOX）技术得到广泛研究,但ANAMMOX菌群对环境要求苛刻且富集困难,系统启动缓慢,限制了其工程应用.前期研究中,构建了用于处理高氨氮低碳氮比养猪废水的升流式限氧生物膜反应器（UOLBR）,经180 d的启动运行实现了以ANAMMOX为主导的脱氮功能.将UOLBR闲置2个月,以COD与TN比为0.6～1.0的干清粪养猪废水为进水,在水力停留时间10 h、25 ℃和出水回流比25∶1的条件下再次启动,考察其处理效果和ANAMMOX功能的恢复情况.结果表明,经过溶解氧分别为2.5～3.0和0.2～0.5 mg/L两个阶段,共计53 d的连续运行,UOLBR的处理效能得以恢复并达到稳定状态,对COD、NH⁺₄-N、TN的平均去除率分别为64.0%,96.5%和91.7%,出水质量浓度分别仅为1,7.0和16.4 mg/L左右.微生物群落结构和物料平衡分析表明,UOLBR系统恢复了以ANAMMOX为主要脱氮途径的特征.该研究可为低碳氮比有机废水ANAMMOX处理系统的启动和运行管理提供指导.

Abstract:

Anaerobic ammonium oxidation (ANAMMOX) is known as the most effective process for nitrogen removal from organic wastewater with low ratio of carbon to nitrogen. But ANAMMOX population is difficult to enrich and sensitive to environment change, which results in a long start-up process. Thus, the tardy start-up of ANAMMOX process is a major issue for engineering application. In preliminary research, an upflow oxygen limitation biofilm reactor (UOLBR) was constructed to treat piggery wastewater with high ammonium (NH⁺₄-N) and low C/N ratio. After the 180-day start-up process, an excellent synchronous removal of chemical oxygen demand (COD) and total nitrogen (TN) was achieved with ANAMMOX as the dominant nitrogen removal pathway. Idled for 2 months, the UOLBR was restarted at 25 ℃ with a hydraulic retention time of 10 h and an effluent reflux ratio of 25∶1. Fed with manure-free piggery wastewater with the COD/TN ratio of 0.6-1.0, performance of the UOLBR during the restart-up process was evaluated. Operation process of the reactor was divided into 2 stages with a dissolved oxygen of 2.5-3.0 and 0.2-0.5 mg/L, respectively. The results showed that the UOLBR could recover from the idle state and a new steady state was reached within 53 days. Within the steady phase, the removal rates of COD, NH⁺₄-N, and TN in the reactor averaged 63.96%, 96.5% and 91.7%, with residues of about 1,7.0 and 16.4 mg/L in the effluent, respectively. Analysis of microbial community along with mass balance indicated that the recovered UOLBR was again characterized by ANAMMOX as the dominant approach for nitrogen removal from the wastewater. This work would be helpful for the start-up and management of ANAMMOX processes.