Effects of pharmaceutical micropollutants on the membrane fouling of a submerged MBR treating municipal wastewater: case of continuous pollution by carbamazepine.
Effects of pharmaceutical micropollutants on the membrane fouling of a submerged MBR treating municipal wastewater: case of continuous pollution by carbamazepine.
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DOI：
10.1016/j.watres.2014.11.027
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发表时间：
2015-02
期刊：
影响因子：
12.8
通讯作者：
Chengcheng Li;C. Cabassud;B. Reboul;C. Guigui
中科院分区：
文献类型：
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作者：
Chengcheng Li;C. Cabassud;B. Reboul;C. Guigui
膜生物反应器（MBR）在城市污水处理和回用中的应用日益广泛，但近年来在水环境中发现的一些微量污染物，尤其是药物污染物，引起了人们的极大关注。因此，通过MBR去除药物微污染物已被广泛研究。但目前国内对生活污水中药物微污染物的存在对MBR污染的影响还缺乏了解。在不同的药物中，决定将重点放在抗癫痫药物卡马西平（CBZ）上，因为它存在于家庭废水中，并且在生物过程中具有持久性，包括MBR。研究了卡马西平连续污染对MBR膜污染的影响。通过进料向MBR中连续引入CBZ（进料中约90 μg L-1CBZ）引起TMP跳变。在MBR中加入CBZ后第1天，TMP的增加速率也显著高于加入CBZ前。这表明由CBZ诱导的药物胁迫导致更严重的膜污染。添加CBZ后，上清液中蛋白质含量在开始几天内显著增加，然后稳定在初始水平，而多糖含量无显著变化。HPLC-SEC分析表明，CBZ的加入诱导了上清液中100-1000 kDa蛋白样SMPs的减少和更显著的10-100 kDa蛋白样SMPs的增加。此外，还发现CBZ在MBR中的加入影响了污泥的微生物活性，因为观察到的外源呼吸速率的轻微抑制（约20%）。CBZ的投加导致MBR中生物量和上清液质量的变化可能是膜污染加剧的原因。该研究还表明，10-100 kDa的蛋白质样SMP可能在MBR运行期间在膜表面上形成的生物饼内积累，并在TMP跳跃现象中发挥重要作用。
Membrane bioreactor (MBR) is increasingly used for municipal wastewater treatment and reuse and great concerns have been raised to some emerging trace pollutants found in aquatic environment in the last decade, notably the pharmaceuticals. As a consequence the removal of pharmaceutical micropollutants by MBRs has been extensively investigated. But there is still a lack of knowledge on the effects of the current presence of pharmaceutical micropollutants in domestic wastewaters on MBR fouling. Among the different pharmaceuticals, it was decided to focus on carbamazepine (CBZ), an anti-epileptic drug, because of its occurrence in domestic wastewaters and persistency in biological processes including MBRs. This paper focuses on the effects of continuous carbamazepine pollution on MBR fouling. A continuous introduction of CBZ into the MBR via the feed (about 90 μg L−1CBZ in the feed) provoked a TMP jump. It occurred just 1 day after the addition of CBZ in MBR and a significantly higher increase rate of TMP was also observed after 1 day after addition of CBZ in MBR, as compared to that before addition of CBZ. This indicates that the pharmaceutical stress induced by CBZ causes more severe membrane fouling. Addition of CBZ was shown to induce a significant increase of the concentration of proteins in the supernatant at the beginning several days then stabilized to original level whereas no significant change was found for polysaccharides. HPLC-SEC analysis showed that addition of CBZ induced a decrease of 100–1000 kDa protein-like SMPs and a more significant increase of 10–100 kDa protein-like SMPs in the supernatant. Moreover it was found that addition of CBZ in the MBR affected the sludge microbial activities, as a slight inhibition (about 20%) of the exogenous respiration rate was observed. The increased membrane fouling could be related to the change in biomass characteristics and supernatant quality after addition of CBZ in MBR. This study allows also suggesting that 10–100 kDa protein-like SMPs might accumulate inside the biocake that was formed on the membrane surface during MBR operation and play an important role in the TMP jump phenomenon.