去除藻毒素的水处理方法

蓝-绿藻水华及其所含毒素已成为我国许多富营养化水源的主要问题.蓝-绿藻所含的毒素是复杂的有机化合物,其中包括神经毒素、肝毒素和皮肤毒素.在水处理时如能有效去除藻类,则藻毒素将随之减少.除藻措施可在水源地或水厂内同时进行.在水源处可采取的措施是预氧化、投加除藻剂和防止水源水因水质或水温而引起的上下分层.一般水厂常规处理工艺不能有效去除藻毒素,可以采用强化混凝、优化粉末活性炭和臭氧以及氯的投加量、用生物活性炭过滤或组合工艺.其中生物预处理、臭氧氧化、粉末或颗粒活性炭吸附有较好去除效果.但是在藻类大量繁殖时,须慎重采用预氧化,否则当用氯或臭氧进行预氧化时,如投药量不当,会使藻细胞破裂,反而析出较多的毒素到水中.蓝-绿藻毒素的最佳去除工艺是臭氧和活性炭相结合的生物活性炭法.

Removal of algal toxins in water treatment

The occurrence of blue-green algal blooms and the production of algal toxins have become major problems for water industry.Toxic cyanobacteria are complex organisms which include nearotoxins,hepatotoxins and dermatoxins.With the removal of algae in water treatment processes,the toxic cyanobacteria will be reduced,and this can be done in both water source and water works.Many conventional water treatment practices(coagulation,sedimentation,filtration and chlorination) are ineffectual in removing them,it is important to use remedial action that can be taken to reduce the toxins risk.The technologies of remove algal toxins involve biological pretreatment,strengthening coagulation,optimizing the dosage of ozone,Cl_2 and activated carbon,etc.Among them the combination of ozone and activated carbon adsorption,i.e.BAC process is the best technology for the removal of toxins.However,attention must be paid to pre-oxidation during the period of a thriving growth of algae since the improper dose of chemicals will damage cyanobacterial cells and consequently result in the release of toxins to water body.