摘要：
Emitter bio-clogging has a close relation with the formation and growth of its internal clogging substances – the biofilms attached in the reclaimed water drip irrigation system. Chlorination with lateral flushing is one of the most effective measures to control the formation of biofilms within emitter, by using the chlorine to inhibit microbial growth and the shearing force to scour the clogging substances out of the system. Based on these, a field experiment using the reclaimed water treated with the cyclic activated sludge system (CASS) technology was carried out in the sewage treatment plant in order to study the controlling effects of 3 types of modes on emitter clogging, which were lateral flushing (flushing velocity was 0.45 m/s), chlorination (chlorination concentration was 5.00 mg/L) and chlorination with lateral flushing; chlorine and lateral flushing frequency were both once every 2 weeks (the time interval was 50 h). The result showed that chlorination with lateral flushing could effectively reduce the microbial contents in the attached biofilms within the emitters, as the phospholipid fatty acids (PLFAs) microbial content was 18.8μg at the second sampling, which was decreased by 52.2%, 44.2%, 73.2% compared with lateral flushing, chlorination and CK (the control, neither lateral flushing nor chlorination) treatment, respectively, and the secreted sticky extracellular polymeric substances (EPS) content was also reduced by 28.0%, 22.9%, 63.9%, respectively. EPS content was 0.47 mg at the second sampling, so that the total amount of clogging substances within emitter decreased by 47.4%, 43.1%, 69.1% with the joint action of the microorganisms and the secreted viscous polymer, thus making the emitter discharge ratio variation (Dra) and coefficient of uniformity (CU) improved by 40.0% and 53.0% respectively at the maximum, and the CU was kept more than 70%. The PLFAs microbial content and EPS content increased from the inlet of the drip irrigation lateral for the same treatment. The results also indicated that the content of EPS in the emitter did not show the same trend in comparison with the chlorination and lateral flushing. The effect of lateral flushing on the secretion of viscous EPS was better than that of chlorination treatment for the head part of emitter, but it was opposite for the middle and end part of emitter. Chlorination and lateral flushing could kill microorganisms, the species of microorganisms marked by PLFAs decreased obviously, and the microbial community structure in the emitter changed, but the types of dominant microorganisms were not changed. Thus it was more likely to delay chlorination starting time, and when the emitter Dra was reduced to 80%, chlorination could still reach a satisfactory controlling effect. Chlorination with the lateral flushing kills microorganisms and scours away the clogging substances at the same time, which makes the biofilm continued to grow and detach. But microorganisms produce resistance, and the production of resistant bacteria increases microbial activity to adapt to the changing external environment. So chlorination with lateral flushing increased microbial activity significantly by 36.5%, 29.0% and 15.7%, respectively, compared with lateral flushing, chlorination and CK treatment. It also decreased the recovery effect on emitter clogging gradually. In general, chlorination with lateral flushing can effectively control emitter clogging for drip irrigation using the reclaimed water treated with CASS.%再生水滴灌系统中灌水器生物堵塞与其内部堵塞物质-附生生物膜的形成、生长有着密切关系，加氯配合毛管冲洗既可以借助加氯杀菌抑制微生物生长，又可以利用毛管冲洗的剪切力作用而促进毛管内部堵塞物质的脱落而冲出系统外部，有望成为一种控制灌水器内部生物膜形成与堵塞的有效措施。为此，借助周期循环式活性污泥法（cyclic activated sludge system，CASS）工艺污水处理厂现场再生水滴灌系统灌水器堵塞试验，研究毛管冲洗、加氯、加氯配合毛管冲洗3种模式对再生水滴灌系统灌水器堵塞控制效果。研究发现加氯配合毛管冲洗可有效降低灌水器内附生生物膜中微生物的数量，较单独的毛管冲洗、加氯以及未进行任何处理条件下微生物磷脂脂肪酸（phospholipid fatty acids，PLFAs）含量分别降低了52.2%、44.2%、73.2%，微生物分泌的黏性胞外聚合物（extracellular polymeric substances，EPS）含量也分别降低了约28.0%、22.9%、63.9%，在微生物及其分泌的黏性多聚物的共同作用下，使得灌水器内部堵塞物质总量分别降低了47.4%、43.1%、69.1%，进而使得灌水器相对平均流量和灌水均匀度最高分别提升了40.0%、53.0%，灌水均匀度（coefficient of uniformity，CU）达到了70%以上。同时表明在推迟加氯起始时间后（即灌水器相对平均流量（discharge ratio variation，Dra）降至80%开始加氯），加氯仍可以达到满意的堵塞控制效果。但加氯配合毛管冲洗也会显著增加微生物活性，分别提升了36.5%、29.0%、15.7%，这也使得对灌水器堵塞的恢复效果逐渐降低。
