供水管网内生物膜与余氯衰减交互作用

为研究生物膜与余氯衰减之间的交互作用,通过静态试验、动态试验相结合的模拟方式,在自制供水管网模拟装置内进行实验.选择铸铁、PE、不锈钢3种管材及1,3,4 mg/L 3个投氯量,多角度研究不同质量浓度余氯存在条件下生物膜的形成和发展差异,以及生物膜作用下的余氯衰减情况,探讨管网内余氯和生物膜的相互影响.结果表明:余氯质量浓度对生物膜的形成和发展具有较显著的影响,另一方面,在生物膜作用下,余氯衰减呈现不同的规律,二者之间交互作用,具体表现为:投氯量升高,PE和不锈钢管内生物量均逐渐降低,而铸铁管内生物量反而升高;在生物膜作用下,余氯衰减分为快速消耗阶段(0~30 min)和稳定消耗阶段(30 min之后);铸铁管内生物膜对余氯衰减状况影响较大,PE管次之,不锈钢管对余氯衰减影响最小;生物膜的生物多样性对余氯衰减影响不大,而生物量与余氯衰减之间关系密切;流速和初始氯质量浓度对余氯衰减影响较大.本研究结果可为供水管网氯消毒的控制以及氯衰减模型的建立提供必要的理论支撑,强化管网水质安全的保障.

Interaction effects between biofilm and chlorine decay in water distribution network

In order to know the interaction effects between biofilm and chlorine decay, influences of chlorine residual on biofilm formation and chlorine decay rules under the existence of biofilm were investigated through static and dynamic simulation in simulated pipelines. Three kinds of pipe materials (cast iron, PE, stainless steel) and 3 chlorine dosage (1,3, 4 mg/L) were chosen. Results show that chlorine decay and biofilm development interacted, and the specific results are as follows. With the increase of chlorine, biomass decreases in PE and stainless steel, while increases in cast iron; with the existence of biofilm, chlorine decay could be divided into two parts: fast decay (0-30 min) and stable decay (after 30 min). Cast iron influences chlorine decay seriously, followed by PE, and the effects of stainless steel is minimum. Influence of biological diversity on chlorine decay is not obvious, while biomass is closely related with chlorine decay. Velocity and chlorine dosage influenced chlorine decay evidently. This research could support disinfection, chlorine decay modeling and water quality security in water distribution network.