【作者】 崔航宇；

【导师】 顾平；

【作者基本信息】 天津大学 ， 市政工程， 2012， 硕士

【摘要】 双膜工艺的广泛应用使得反渗透(RO)浓水产生量剧增,RO浓水中的难生物降解有机物和高含盐量成为其资源化无害化处理的难题,尤其是有机物对RO膜危害严重,成为RO浓水进一步回收利用的最大障碍。本文中采用两种不同工艺针对RO浓水中的有机污染物进行去除,使浓水中溶解性有机碳(DOC)含量低于10 mg/L,能够达到反渗透进水的水质要求,在提高RO工艺回收率的同时减小RO浓水的直接排放量。生化处理法作为有机物降解最彻底最经济的方法,首先被用来去除RO浓水中有机污染物。本研究采用臭氧和曝气生物滤池组合工艺,利用臭氧的强氧化性提高RO浓水的可生化性,然后在高盐水中驯化微生物进行有机物降解。实验中原水臭氧投量20 mg/L,接触时间25 min,臭氧氧化后的水在储水罐放置12 h后进入曝气生物滤池,水力停留时间2 h。实验结果显示,该组合工艺对有机物去除效果不明显,COD去除率仅为11.8%,难以达到处理要求。膜分离技术的日益成熟,为粉末活性炭(PAC)吸附-微滤(MF)组合工艺的工业化应用提供了技术保障。研究中提出了PAC-MF累积二级逆流吸附方法去除RO浓水中有机物,利用微滤高效截留PAC颗粒的能力,延长了PAC在反应器中的停留时间,充分发挥了PAC的吸附容量。根据理论计算,在相同吸附效果下,累积二级逆流吸附较单级吸附操作节约42.3%的PAC,通过静态烧杯实验和动态反应柱实验均验证了理论计算的正确性。采用该工艺技术,DOC能达到出水目标值,且PAC的投加对微滤膜污染控制也很有利,运行结束后仅物理清洗即可使膜比通量值恢复至原来的89.1%。同时,PAC-MF组合工艺相比于其他RO浓水处理工艺,经济可行,是很有发展前途的处理工艺。更多还原

【Abstract】 The extensive application of dual-membrane process makes a rapid increase of reverse osmosis (RO) concentrate. Due to the biorefractory pollutants and high salt content, RO concentrate is difficult to reuse and harmlessly dispose, particularly organics cause a serious fouling to RO membrane, becoming the biggest obstacle for the further recovery of RO concentrate. Two different processes for the removal of organic pollutants from RO concentrate were studied in this paper, aimed to reduce the dissolved organic carbon (DOC) to less than 10 mg/L, which was required by the RO feeding. As a result, the RO system’s recovery rate would be improved while discharge of RO concentrate could be reduced.Biochemical treatment as the most cost-effective and thorough method for organic matter degradation was firstly used to remove the organic pollutants from RO concentrate. The combination of ozonation and biological aerated filter was used in the study. Ozone with its strong oxidation was introduced to improve the biodegradability of RO concentrate and acclimated microorganism in high salinity wastewater system was intended to degrade organic pollutants. In the experiments, the dosage of ozone was 20 mg/L and contact time was 25 minutes for raw water. After ozonation, RO concentrate was stored for 12 hours in a storage tank, and then elevated into BAF with the hydraulic retention time of 2 hours. The result showed that the combined process had a little effect on degradation of organics, with only 11.8% of COD removal, which was difficult to reach the processing demands.Technical guarantee for industrial application was provided by the hybrid process with wide use of membrane technology. Powdered activated carbon (PAC) adsorption and microfiltration (MF) accumulative two-stage countercurrent adsorption process was put forward in this study. In the process, PAC was retained in the reactor by microfiltration, which could prolong the adsorption time of PAC, and play a great role in use of adsorption capacity. According to the theoretical calculation, accumulative two-stage countercurrent adsorption could save approximately 42.3% PAC than single-stage operation in the same adsorption. Moreover, the theoretical calculation was proved by jar test and bench-scale test, and DOC in the effluent could reach the target. In addition, it was favorable to control MF membrane fouling by adding PAC. MF membrane specific flux was recovered to 89.1% of the original one by physical cleaning after bench-scale test. Meanwhile, compared to other RO concentrate treatment technologies, hybrid process of PAC and MF as a promising treatment process was cost-effect and feasible.更多还原