铁盐投加对浸没式膜生物反应器除磷及膜污染的影响。
Effect of ferric and ferrous iron addition on phosphorus removal and fouling in submerged membrane bioreactors.
机构信息
Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia; UNESCO Centre for Membrane Science and Technology, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
出版信息
Water Res. 2015 Feb 1;69:210-222. doi: 10.1016/j.watres.2014.11.011. Epub 2014 Nov 18.
The effect of continuously dosing membrane bioreactors (MBRs) with ferric chloride (Fe(III)) and ferrous sulphate (Fe(II)) on phosphorus (P) removal and membrane fouling is investigated here. Influent phosphorus concentrations of 10 mg/L were consistently reduced to effluent concentrations of less than 0.02 mg/L and 0.03-0.04 mg/L when an Fe(III)/P molar ratio of 4.0 and Fe/P molar ratio (for both Fe(II) and Fe(III)) of 2.0 were used, respectively. In comparison, effluent concentrations did not decrease below 1.35 mg/L in a control reactor to which iron was not added. The concentrations of supernatant organic compounds, particularly polysaccharides, were reduced significantly by iron addition. The sub-critical fouling time (tcrit) after which fouling becomes much more severe was substantially shorter with Fe(III) dosing (672 h) than with Fe(II) dosing (1200-1260 h) at Fe/P molar ratios of 2.0 while the control reactor (no iron dosing) exhibited a tcrit of 960 h. Not surprisingly, membrane fouling was substantially more severe at Fe/P ratios of 4. Fe(II) doses yielding Fe/P molar ratios of 2 or less with dosing to the aerobic chamber were found to be optimal in terms of P removal and fouling mitigation performance. In long term operation, however, the use of iron for maintaining appropriately low effluent P concentrations results in more severe irreversible fouling necessitating the application of an effective membrane cleaning regime.
本文研究了向连续投加氯化铁（Fe(III)）和硫酸亚铁（Fe(II)）的膜生物反应器（MBR）中添加铁对除磷和膜污染的影响。当 Fe(III)/P 摩尔比为 4.0 且 Fe/P 摩尔比（Fe(II)和 Fe(III)）分别为 2.0 时，进水磷浓度为 10 mg/L，始终能将磷浓度稳定降低至低于 0.02 mg/L 和 0.03-0.04 mg/L。相比之下，未添加铁的对照反应器中，出水浓度未降至 1.35 mg/L 以下。添加铁后，上清液中有机化合物，尤其是多糖的浓度显著降低。在 Fe/P 摩尔比为 2.0 时，与 Fe(II)投加（1200-1260 h）相比，Fe(III)投加（672 h）使临界污染时间（tcrit）明显缩短，临界污染时间是指污染变得更严重的时间。在对照反应器（未投加铁）中，tcrit 为 960 h。不出所料，在 Fe/P 比值为 4 时，膜污染更为严重。在好氧室投加 Fe(II)以达到 Fe/P 摩尔比 2 或更低的剂量，在除磷和减轻污染方面的性能最佳。然而，在长期运行中，为了保持适当低的出水磷浓度而使用铁会导致更严重的不可逆污染，需要应用有效的膜清洗方案。
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