Department of Civil Engineering, University of Calgary, Calgary, AB, Canada.
Administrator - Private Sewage Systems, Standards Development and Support - Mechanical, Alberta Municipal Affairs, Canada.
Sci Total Environ. 2021 Feb 10;755(Pt 2):142446. doi: 10.1016/j.scitotenv.2020.142446. Epub 2020 Sep 22.
This study aimed to investigate the efficacy of private septic systems retrofitted into aerobic bioreactors with 'SludgeHammer' technology. In addition, the study attempted to characterize the strength of domestic wastewater released from 'green' households practicing water conservation strategies. Ten retrofitted onsite septic systems were studied in the Edmonton area, Alberta (AB) Canada during winter. These systems could remove BOD and TSS by 92 ± 5 and 92 ± 6% respectively which, according to Albertan regulatory standards, were characteristic removal efficiencies of the secondary treatment in the subsequent drain field. These removal efficiencies were remarkable given the strength of the influent wastewater. The raw wastewater carried significantly high pollutant concentrations (1160 ± 350 mg BOD/L, 1653 ± 1174 mg TSS/L, 99 ± 19 mg NH-N/L, 100 ± 56 mg TN/L, and 39 ± 28 mg PO-P/L), characterizing it as high-strength domestic wastewater. Mixing provided by the aerator could only suspend 1/34 (3% m/m) of the solids in the bioreactor and consequently released significantly low solid concentrations (195 ± 206 mg TSS/L) into the final treatment component. As such, this technology did not impair the natural function of septic tanks or did not create any unintended excessive solid loading on drain field as a consequence of the added mixing energies provided by the active aeration. Nitrogen balance suggested the possibility of simultaneous nitrification and denitrification (SND) in the aerobic bioreactors. In some cases, PO-P removal efficiency was as high as that in enhanced biological phosphate removal (EBPR) process (81-97%). Phosphorus balance estimated that non-assimilative pathways (i.e., EBPR + biologically induced phosphate precipitation (BIPP)) contributed 50-99% to overall phosphorus removal in the system. Long HRTs, high influent BOD and anaerobic/aerobic zoning in the bioreactor most likely provided favorable conditions for SND and high phosphorus removal efficiencies in the retrofitted onsite wastewater treatment systems (OWTS).
本研究旨在探讨经“SludgeHammer”技术改造的有氧生物反应器中私人化粪池的效能。此外，本研究还试图对采用节水策略的“绿色”家庭排放的生活污水的强度进行特征描述。在加拿大艾伯塔省（AB）埃德蒙顿地区，冬季研究了 10 个经改造的现场化粪池系统。这些系统可以分别去除 92±5%和 92±6%的 BOD 和 TSS，根据艾伯塔省的监管标准，这是后续排水场中二级处理的典型去除效率。鉴于进水污水的强度，这些去除效率非常显著。原污水携带的污染物浓度非常高（1160±350mg BOD/L、1653±1174mg TSS/L、99±19mg NH-N/L、100±56mg TN/L 和 39±28mg PO-P/L），将其定性为高强度生活污水。曝气器提供的混合只能悬浮在生物反应器中 1/34（m/m）的固体，因此，仅有非常低的固体浓度（195±206mg TSS/L）释放到最终处理组件中。因此，这种技术既没有损害化粪池的自然功能，也没有因为活性曝气提供的额外混合能量而对排水场造成任何意外的过度固体负荷。氮平衡表明，有氧生物反应器中可能存在同时硝化反硝化（SND）。在某些情况下，PO-P 的去除效率高达增强生物除磷（EBPR）过程（81-97%）。磷平衡估计，非同化途径（即 EBPR+生物诱导磷沉淀（BIPP））对系统中总磷去除的贡献为 50-99%。长 HRT、高进水 BOD 和生物反应器中的厌氧/好氧分区很可能为 SND 和经改造的现场废水处理系统（OWTS）中的高磷去除效率提供了有利条件。
