膜生物反应器用于居民区生活污水处理与回用

Membrane Bioreactor technology for the treatment and reuse of mixed domestic wastewater from residential areas

摘要:

本文采用“缺氧/厌氧-生物膜技术，结合活性炭过滤、紫外线氯消毒”的组合工艺深度处理居住区生活污水，分别以冲洗厕所和景观用水为目标，考察再生水的水质状况和主要参数；对比研究以混合生活污水和灰水分别作为中水源的技术和经济适用性。中试研究结果表明，以居住区生活污水（化粪池出水）作为中水源，运行条件停留时间8 h、污泥浓度3500~7500 mg•L-1、出水无色无味，化学需氧量浓度低于30 mg•L-1，五日生化需氧量浓度低于3 mg•L-1，氨氮浓度低于3.0 mg•L-1，可以稳定达到杂用水标准，但总氮、总磷浓度无法满足景观用水要求；模拟原污水（化粪池进水）的污染物浓度比例，运行条件为停留时间10 h、污泥龄50 d、回流比为200%、污泥浓度5500~6000 mg•L-1、外加聚合铝（有效铝）4~5 mg•L-1时，再生水的水质均优于冲厕和景观用水标准。在达到相同的再生水水质条件下，居住区的生活污水混合收集处理比灰水单独收集处理的工艺流程复杂，处理费用比后者高0.32元•m-3。居住区污水资源化采用何种收集和再生方式不仅要考虑技术经济合理性，还需结合居住区再生水的用途和用水量、当地气候条件等因素综合确定。

Abstract:

In many Chinese residential communities, reclaimed water reuse system meet the problem of long-term application for the poor water quality and sensory discomfort. Aimed to meet the “Standard of Urban Wastewater Reuse” for miscellaneous water consumption (GB/T 18920-2002) and scenic environment use (GB/T 18921-2002), a pilot-scale Anoxic/Oxic Membrane Bioreactor (AO-MBR) followed by activated carbon filter and ultraviolet combined chlorine disinfection devices were installed to treat the mixed domestic wastewater in a residential area in north China. The objectives of the research were to investigate the reclaimed water qualities and optimize the main operating parameters; furthermore, to analyze the technical and economic suitability for treatment of the mixed domestic wastewater with grey water only. The results showed that, when the mixed domestic wastewater (effluent of septic tank) was chosen for treatment, under the conditions of Hydraulic Retention Time (HRT) 8h, mixed liquor suspended solids (ρMLSS) 3500~7500 mg•L-1, the effluent was colorless and odorless, the chemical oxygen demand (ρCOD), Biochemical Oxygen Demand(ρBOD5) and ammonia nitrogen(ρNH3-N) was respectively below 30 mg•L-1, 3 mg•L-1 and 3.0 mg•L-1, which can stably meet the “GB/T 18920-2002”, however, the total nitrogen(ρTN) and total phosphorus(ρTP) concentration of effluent can’t meet the requirements of “GB/T 18921-2002”; While simulating the ρCOD: ρTN: ρTP ratio of the raw wastewater (influent of septic tank), under the conditions of HRT 10 h, SRT 50 d, the recycling ratio 200%, ρMLSS 5500~6000 mg•L-1, the dosage of poly-aluminum chloride(ρPAC) 4~5 mg•L-1, the effluent quality was better than the “GB/T 18920-2002” and the “GB/T 18921-2002”. To achieve the same reclaimed water quality, the mixed domestic wastewater treating process is more complicated than that of the grey water, at the same time, the operating cost is 0.32 Yuan•m-3 higher than the later. Therefore, from the views economic and technical feasibilities, it should be taken into account the demand and potential usage of the reclaimed water, the local climate conditions during selecting a suitable wastewater collecting and treating system in residential areas.