Bucknell University, Lewisburg, Pennsylvania.
DC Water, Washington, District of Columbia.
Water Environ Res. 2019 May;91(5):386-398. doi: 10.1002/wer.1028. Epub 2019 Feb 12.
The goal of this study was to evaluate using feed dilution/solids retention time (SRT) control to manage potential ammonia inhibition in highly loaded anaerobic digesters after thermal hydrolysis. The study compared three digesters operated at the same target volatile solids (VS) loading rate of 5.5 kg VS/d-m , but at different feed concentrations resulting in SRTs of 10, 15, and 18 days. Lowering the feed concentration decreased the digester total ammonia nitrogen concentrations which averaged 1,580, 2,610, and 3,080 mg -N/L for the 10-, 15-, and 18-day digesters. The VS reduction and methane yields were equivalent for the 15- and 18-day digesters and about 4% lower for the 10-day digester. Ammonia inhibition of the 18-day digester occurred early in the study, but the system acclimated over time. Feed dilution reduced the viscosity and the potential for volume expansion due to gas holdup and foaming. PRACTIONER POINTS: Feed dilution reduces digester ammonia concentrations and inhibition potential without sacrificing digester performance at lower SRTs. Feed dilution greatly reduces digester viscosity and associated issues with digester volume expansion due to gas holdup and foaming. Operating at the lower SRT does not impact cake solids after dewatering and substantially decreases polymer demand for conditioning.
本研究的目的是评估在经过热水解后，利用饲料稀释/固体停留时间（SRT）控制来管理高负荷厌氧消化器中潜在的氨抑制。该研究比较了三个以相同的目标挥发性固体（VS）负荷率 5.5 kg VS/d-m 运行的消化器，但进料浓度不同，导致 SRT 分别为 10、15 和 18 天。降低进料浓度会降低消化器中的总氨氮浓度，对于 10、15 和 18 天的消化器，平均浓度分别为 1580、2610 和 3080 mg-N/L。VS 减少和甲烷产率在 15 天和 18 天的消化器中相当，而在 10 天的消化器中约低 4%。18 天消化器中的氨抑制在研究早期发生，但系统随着时间的推移逐渐适应。饲料稀释降低了消化器中的氨浓度和抑制潜力，同时在较低 SRT 下不会影响消化器性能。饲料稀释大大降低了消化器的粘度和由于气体夹带和泡沫引起的体积膨胀的潜在风险。实践要点：饲料稀释可降低消化器中的氨浓度和抑制潜力，同时在较低 SRT 下不会影响消化器性能。饲料稀释可大大降低由于气体夹带和泡沫引起的消化器粘度和体积膨胀相关问题。在较低的 SRT 下运行不会影响脱水后的饼状固体，并且大大减少了调理所需的聚合物需求。
