Reverse electrodialysis for power generation using seawater/municipal wastewater: Effect of coagulation pretreatment
Reverse electrodialysis for power generation using seawater/municipal wastewater: Effect of coagulation pretreatment
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DOI：
10.1016/j.desal.2020.114356
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发表时间：
2020-05-01
期刊：
影响因子：
9.9
通讯作者：
Higa, Mitsuru
中科院分区：
文献类型：
--
作者：
Mehdizadeh, Soroush;Yasukawa, Masahiro;Higa, Mitsuru
反向电渗析（RED）将盐度梯度能量（SGE）转化为电能。海水和河水是RED最有前途的进料解决方案，但如果废水处理厂靠近大海，则城市废水而不是河水也是可以接受的，因为河水通常用于人类需求，即，饮用水和农业灌溉。此外，还必须考虑混合点（微咸水区）的环境影响。废水预处理是必要的，以防止在随后的RED过程中性能下降。本研究以模拟和真实的城市污水和海水为研究对象，考察了聚合氯化铝（PAC）作为混凝剂预处理对RED性能的影响。结果表明，混凝后的PAC残留物的存在下产生负面影响，随后的RED过程中，特别是因为增加阳离子交换膜的电阻，这导致在发电量减少40%。然而，优化的PAC剂量（和较低量的PAC残留物）导致RED发电量提高20%，因为50%的废水有机物含量已被去除。因此，混凝预处理与优化的PAC剂量是有用的RED发电前，当使用城市污水。
Reverse electrodialysis (RED) converts salinity gradient energy (SGE) into electrical energy. Seawater and river water are the most promising feed solutions for RED, but municipal wastewater instead of river water could be acceptable if the wastewater treatment plant is close to the sea because river water is often used for human demands, i.e., for drinking water and agricultural irrigation. In addition, the environmental impact at the mixing point (the brackish water region) must be considered. Wastewater pretreatment is necessary to prevent performance reduction in the subsequent RED process. In this study, the effect of pretreatment using polyaluminum chloride (PAC) as a coagulant on the RED performance was investigated using model and real municipal wastewater and seawater samples. The results reveal that the presence of PAC residue after coagulation negatively affected the subsequent RED process, especially because of the increased cation exchange membrane resistance, which resulted in a 40% reduction in power generation. However, the optimized PAC dosage (and lower amount of PAC residue) resulted in a 20% improvement in RED power generation because 50% of the wastewater organic content had been removed. Thus, coagulation pretreatment with the optimized PAC dose is useful before RED power generation when using municipal wastewater.