臭氧对陶瓷膜超滤-生物活性炭组合工艺效果的影响

利用处理量为3L/d的臭氧陶瓷膜-生物活性炭(BAC)(工艺Ⅰ)和陶瓷膜-BAC(工艺Ⅱ)2种组合工艺处理受污染的原水,研究了工艺对原水中浊度、氨氮和有机物的去除效果,同时考察了臭氧对膜通量和BAC的影响.结果表明,未投加臭氧和2.0mg/L臭氧投加量下,两种组合工艺可去除原水中96%以上的浊度.组合工艺均可去除原水中1.0~2.0mg/L的氨氮.提高溶解氧浓度至30mg/L可强化氨氮的去除能力,两种组合工艺可至少彻底去除5.5mg/L的氨氮.投加2mg/L臭氧后,工艺Ⅰ可去除原水中48.3%的总有机碳(TOC)和51.8%的UV254.工艺Ⅱ对TOC和UV254的平均去除率分别为51.1%和48.2%.臭氧对浊度的去除无影响,但臭氧可改变部分有机物的结构,减轻膜的有机物污染.与未投加臭氧的工艺Ⅱ相比,投加臭氧使工艺Ⅰ中的膜通量提高了25%~30%.但残留臭氧可能影响后续BAC中的微生物,对BAC去除氨氮和有机物的能力产生不利影响.

Effect of ozone on the combination performance of ceramic membrane ultrafiltration-biological activated carbon filtration

Two combination processes, including ozonation-ceramic membrane-biological activated carbon (BAC) (processⅠ) and ceramic membrane-BAC (processⅡ), were tested to treat polluted raw water. The performance was evaluated with the removal efficiencies of turbidity, ammonium and organic matters in a scale of 3L/d.The effects of ozone on membrane flux and BAC were also considered. More than 96% of turbidity was removed by both combination processes either with or without ozone addition. The ammonium that can be removed by both processes was limited to 1.0~2.0mg/L. Increasing the dissolved oxygen to 30.0mg/L can lead to a complete removal of ammonium with the concentration as high as 5.5mg/L. The average removal efficiencies of the total organic carbon (TOC) and ultraviolet absorbance at 254nm were 48.3% and 51.8% for processⅠwithout ozone addition, 51.1% and 48.2% for processⅡwhen ozone dosage was 2.0mg/L. Ozonation had no effect on turbidity removal, while it resulted in the changes of organic molecular structure at an ozone dosage of 2.0mg/L and this helped alleviate the membrane fouling. Membrane flux in processⅠincreased by 25%~30% compared with that in processⅡ with no ozone addition. However, residual ozone may affect the microbial activities in the BAC, which impacted the removals of organic matter and ammonia negatively.