Abstract

The removal of nickel, lead, arsenic, and zinc was investigated by a lab-scale submerged membrane bioreactor (MBR) combined with granular activated carbon (GAC). Membrane fluxes of 16 L m⁻² h⁻¹, 20 L m⁻² h⁻¹, and 24 L m⁻² h⁻¹ with corresponding hydraulic retention times (HRTs) of 12.8 h, 10.4 h, and 9.2 h were applied as variables to examine their influence upon the removal efficiency. Synthetically prepared wastewater was pretreated in the MBR and GAC adsorption was employed as the post-treatment. Under the lowest applied flux value or, equivalently, the highest HRT applied, chemical oxygen demand (COD), ammonium (NH₄-N) and phosphate (PO₄-P) removals were found to be the highest (96.8%, 98.9% and 46%, respectively) for the MBR effluent. These results may be considered to be the result of alleviated membrane fouling and greater biomass growth. The highest heavy metal removal efficiency after the first treatment stage (i.e. the MBR effluent) was obtained at the lowest flux value of 16 L m⁻² h⁻¹. Ni, Pb, Zn, and As removals were measured to be equal to 96.9%, 98.3%, 98% and 8.5%, respectively. More important, the heavy metal concentrations were below the limit of detection after the GAC post-treatment; over 99% removal was achieved for all heavy metals. The adsorption of heavy metal ions onto the GAC may minimize biomass exposure to their toxicity, thereby creating the conditions for further improved MBR-GAC system performance. Coupling MBR technology with GAC adsorption seems a promising option for the effective treatment of wastewater containing heavy metals.

摘要

通过实验室规模的浸没式膜生物反应器（MBR）和颗粒状活性炭（GAC）进行了镍，铅，砷和锌的去除研究。施加了16 L m ^-2 h ^-1，20 L m ^-2 h ^-1和24 L m ^-2 h ^-1的膜通量，相应的水力停留时间（HRT）为12.8 h，10.4 h和9.2 h作为变量来检查其对去除效率的影响。合成制备的废水在MBR中进行预处理，GAC吸附作为后处理。在最低的应用通量值或等效的最高HRT下，化学需氧量（COD），铵（NH ₄ -N）和磷酸盐（PO ₄-P）的清除率最高（分别为MBR废水的96.8％，98.9％和46％）。这些结果可以被认为是减轻的膜污染和更大的生物量生长的结果。在第一个处理阶段（即MBR废水）之后的最高重金属去除效率是在最低通量值为16 L m ^-2 h ^{-1时获得的}。测得的Ni，Pb，Zn和As去除率分别等于96.9％，98.3％，98％和8.5％。更重要的是，GAC后处理后的重金属浓度低于检出限。所有重金属的去除率均超过99％。重金属离子在GAC上的吸附可最大程度地降低生物量对其毒性的暴露，从而为进一步提高MBR-GAC系统性能创造条件。MBR技术与GAC吸附耦合似乎是有效处理含重金属废水的一种有前途的选择。