藻类对供水的影响研究论文

Cherish the water Good afternoon!my dear ladies and gentalman!today,I am glad to stand here to give you a speech and thank you giving me such a chance,I will not disappoint you. we all know that we can not live without water,although there is much water on the earth, but the water which we can drink ,it is very litte .It just occunt for thirty percent ,the other seventy percent is seawater.and the seventeen percent of the thirty percent is on the north pole and south pole's glancier.so we can't drink it maybe someone will ask me why we don't drink the seawater ? there is much seawater on the earth ,isn't there?Yes,I have to admit that is truth,but do you know why we can't drink the seawater? Because the seawater include much poisonous thing and saltcontant it's bad for our health. Now, because humankind built a lot of fictory on the earth, it made the water became yellow from green and the sky became grey from blue, the north pole and south pole's glancier has began to thaw,and the sealelvel and temperature has razen up. when I was a child , there is a river in my hometown, at that time ,there are many frogs and fishs in the river ,when spring come ,many frogs sang songs onthe bank ,many children swam in the river, it made the river full of vim .but now it has chenged , it became dirty and smelly,fishs and frogs disappear from this river ,it just leave much rabbish and weast-products in the river.accroding to this rivers experence ,I think if we don't control it .we will distroy ourselves. maybe someone will laugh at me and think I say frighting thing just to cause alarm,but we all know that the weather is more and more hot and arid,many river has began to dried-up, and many place became desert. so, ladies and gentalman, we must cherish the waterand protect our environment or it will do harm to us. thanks for listening !

影响水质 多了堵塞管道

3 藻类对制水的影响含藻原水进入净水厂后，对制水生产工艺、药耗以及构筑物池壁都会产生极大的不利影响，主要表现在以下几个方面：1．在光合作用下，水中pH值升高，且由于藻类作用，溶解氧增加，矾花密度降低，沉淀去除率下降，导致需要投加的混凝剂增多，高藻水的处理需要消耗大量的混凝剂。2．藻类物质在滤池中可大量繁殖，会使滤料层堵塞，使过滤周期缩短，减少产水量，增加冲洗水量并影响出水水质。3．对混凝土池壁构成很大的威胁，如长沙三水厂构筑物池壁由于藻类等物质的长期腐蚀，致使池壁粗糙老化，反过来又给藻类物质的寄生繁殖，水垢、青苔的附着生长，提供了有利的栖息场所。4．藻类细胞成层成为粘质物，附在混凝土池壁表面，形成一层润滑层，既影响制水过程中的感官质量，又增加了洗池的频率和费用，以及工人的劳动强度。5．藻类的存在使水质变化，从而干扰水处理操作，造成处理上的麻烦，生长着和死亡的藻类都会使水中有机物增加，增加氯耗，高藻水的处理更需要消耗大量的消毒剂。6．对水质影响更为严重的是有些藻类的降解产物中含有四氯乙烷、二甲基二硫化物等毒性物质，能引起人、动物中毒。

藻类及藻毒素对供水工程和饮用水安全的影响主要是富营养化。动物饮用含有有毒藻类的水而死亡的事故也经常发生。包括生物肽（肝毒素）、生物碱（神经毒素）和脂多糖（皮炎毒素）等。这种急性毒素可使饮用此水的陆生动物中毒死亡，其慢性毒素则以微囊藻毒素为代表，可经口、皮肤或随水气挥发等途径进入人体造成危害。藻毒素可以通过食物链传递，而且藻毒素易溶与水，耐热性强，自然降解过程十分缓慢，常规的方法很难完全消除水体中的藻毒素。家畜及野生动物饮用含藻毒素的水后，会出现腹泻、乏力、厌食、呕吐、嗜睡、口眼分泌物增多等症状，甚至死亡。