原水厂集水井溶解氧过低原因分析及应对控制措施

Analysis and Solution of Lower Dissolved Oxygen in Water-Collecting Well at Raw Water Plant

原水厂取水自流管投运3年后出现了集水井溶解氧较原水偏低现象,经分析与探摸验证发现主要是由于自流管管壁内零散分布淡水壳菜群落等好氧微生物,在水温适宜时大量繁殖过度耗氧;此外,自流管管道流速过低,也加剧了这一过程。为避免其后续对供水水质和管道输水能力可能造成的不利影响,制定并实施了取水头部投加次氯酸钠药剂的方案与措施,抑制或灭活管道内好氧生物生长繁殖等活动,同时加大流速对剥落的淡水壳菜贻贝类水生生物的有效冲刷。生产实践表明,5月中下旬在取水头部开始投加次氯酸钠,并根据集水井内余氯等水质情况以及排出的贻贝生物数量、水质数据,适当调整投加方式、投加量、持续时间,能有效确保管道内好氧生物的排除效果,同时不对后续生产工艺造成负担。

Dissolved oxygen in water-collecting well at raw water plant was lower than that of source water,and it occurred 3 years after water intake pipe was put into operation.It was found that aerobic microorganisms such as Limnoperna fortunei in the wall of water intake pipe were multiplied at a suitable temperature and excessively consume oxygen.In addition,the flow rate of water intake pipes was too low,which also exacerbates this process.Considering the unfavorable influence of aerobic growth on water quality and the capacity of pipe transmission,the technical schemes and measures of adding and adjusting the concentration of sodium hypochlorite in water intake head were taken to inhibit or inactivate the activities of aerobic growth and reproduction.Velocity in water intake pipe was increased to effectively scour aerobic microorganisms in this process.Practice showed that sodium hypochlorite in water intake head were taken about mid-late May,the method,amount and duration were adjusted appropriately according to the residual chlorine in the water-collecting well and the number of mussels discharged and the water quality data.It can get rid of aerobic organisms in pipe effectively and does not burden subsequent process.