Abstract

The effect of applying different hydraulic retention times (HRTs) was investigated for a lab-scale membrane bioreactor (MBR) treating domestic wastewater. The submerged flat-type ultrafiltration MBR was operated under three HRTs (576 min, 462 min, and 372 min) corresponding to three operating periods to investigate its efficiency in removing organic content and nutrients from domestic wastewater. The chemical oxygen demand (COD) decreased from 99 to 96.5% with the HRT decreased from 576 min to 462 min. The bacteria performing nitrification were affected by the HRT change: the ammonium (NH₄-N) removal dropped from 98.5% (HRT of 576 min) to 74.2% (HRT of 462 min). With the HRT adjusted to the lowest value of 372 min, the COD and NH₄-N removals were 94.4% and 55.8%, respectively. The phosphate (PO₄-P) removal was 59.1%, 34.4%, and 28% during periods 1, 2 and 3, respectively. In terms of the COD removal efficiency, the treated effluent met the Turkish limits for discharge to the receiving water during all of the operating periods. The system performance was suitable in terms of NH₄-N removal for periods 1 (HRT of 576 min) and 2 (HRT of 462 min). However, applying the operating conditions of period 2 (i.e., maintaining the HRT at 462 min) requires additional post-treatment (e.g., low-cost chemical precipitation) to enhance the PO₄-P removal.

摘要

对于实验室规模的膜生物反应器（MBR）处理生活污水，研究了采用不同的水力停留时间（HRT）的效果。淹没式平板式超滤MBR在三个HRT（576分钟，462分钟和372分钟）下分别对应三个操作周期进行操作，以研究其从生活废水中去除有机物和养分的效率。化学需氧量（COD）从99％降低至96.5％，而HRT从576分钟降低至462分钟。进行硝化的细菌受到HRT变化的影响：铵（NH ₄ -N）的去除率从98.5％（576分钟的HRT）下降到74.2％（462分钟的HRT）。将HRT调整为372分钟的最小值后，COD和NH ₄-N去除率分别为94.4％和55.8％。在期间1、2和3期间，磷酸盐（PO ₄ -P）的去除率分别为59.1％，34.4％和28％。就COD去除效率而言，在所有运行期间，处理后的废水均达到土耳其的排放限值。就时段1（HRT为576分钟）和时段2（HRT为462分钟）而言，就NH ₄ -N的去除而言，系统性能是合适的。但是，应用阶段2的运行条件（即，将HRT保持在462分钟）需要进行额外的后处理（例如，低成本的化学沉淀）以提高PO ₄ -P的去除率。