以双膜工艺为核心的城市平急两用水厂中试研究

Pilot study on urban daily-emergency dual using water plant with dual membrane process

武汉梁子湖水厂为国内较早的大型平急两用水厂,以平原湖泊为水源,应急供水规模50万m^(3)/d,日常供水规模20万m^(3)/d,在净水流程中采用了双膜工艺,并开展了中试研究。中试结果表明,针对原水低浑浊度、高有机物、季节性高藻等问题,采用沉淀-臭氧活性炭-超滤-部分纳滤的净水工艺,出水水质良好、运行稳定,并可较好应对低温低浊、藻类暴发等季节性水质问题。臭氧活性炭环节可有效缓解纳滤有机污染,超滤膜对于浊度有着很好的控制,二者对工艺流程总体的稳定运行有积极作用。运用中试结果,梁子湖水厂开展了工艺设计,纳滤规模10万m^(3)/d,对应日常工况COD_(Mn)可保持在1.5 mg/L左右,应急工况COD_(Mn)可保证在3 mg/L以内,并投加二氧化碳调节原水pH以降低残余铝含量从而减轻日后可能的纳滤膜污染。

Wuhan Liangzihu Water Plant is the first large-scale flat-emergency dual-purpose water plant in China.It takes plain lakes as its water source,with emergency water supply scale of 500000 m^(3)/d and daily water supply scale of 200000 m^(3)/d.Dual membrane technology is also adopted in the water purification process.The pilot test results show that for raw water characterized by low turbidity,high organic and seasonal high algae,the use of precipitation-O3-BAC-UFpartial NF process,effluent water quality is good,stable operation.O3-BAC can effectively alleviate NF membrane organic pollution,and UF has a good control of turbidity,both of which have a positive effect on the overall stable operation of the process.Based on the pilot test results,Liangzihu Water plant carried out the process design,in which the scale of NF is 100000 m^(3)/d,COD_(Mn) can be maintained at about 1.5 mg/L under daily working conditions,and can be kept within 3 mg/L under emergency conditions.Carbon dioxide is added to the raw water to reduce the residual aluminum content and control possible UF membrane contamination.