Heavy Metals In Waste Water Treatment Technology

The article discusses the questions about the pollution of heavy metal such as Cd, Hg, Pb, As, Cr based the large numbers of research or study literatures and datas. The questions involved many sides such as the input of heavy metal to environment, the transferring and transforming of heavy metal in chain which be formed with water, soil, plant and animal, the influence and harm of heavy metal to life-forms, the purifying of heavy metal in every kinds of waste and environment.As the gross of As and Hg that input to environment approaches 47000t/a and 20000t/a, we have to think the pollution of heavy metal is very serious at present. We must pay attention to it.After enter to environment and occur complicated chemistry process, heavy metal may become many kinds of pollutions which be in different shape and different struction. For example, in soil, heavy metal can be differentiated five shapes generally, namely, dissolved, permutable by feeble permutoid, permutable by strong permutoid, original mineral, secondary mineral.The transferring and transforming mean the long period pollution of heavy metal in chain which formed with water, soil, plant and animal. Actually, heavy metal may be concentrated in the body of life-forms. They can harm the health of human through the food chain finally. Hg may be concentrated 105 times from water to invertebrate. The harm of methyl mercury compound cause the three main symptoms in human, namely, cerebell-muscle locomotion malajustment, eyeshot shrinking, pronunciation embarrassment. Hg is embryo-poison and procreation -poison also.We designed some treatment schniques to control the input and harness the pollution bases the chemistry characteristi of hevy metal. Chemistry method, reverse-infiltration method, adsorption method, evaporation-concentration method, electroanlysis method, electrodialysis method have been used successfully.Thebiology-technique for treating the abio-heavy metal hydronium in liquid waste have been investigated and tryouted positively at present.Microorganism have the potential power to central or treat and harness heavy metal pollutions. (1)Activated sludge is a new kind material for treating heavy metal pollution perhaps. Activated sludge can protect the live-forms in coexisted system from harm of heavy metal intut to later. (2)Dryness sorbent be made of float-swim hydrophily algaes and microzyme have the ability to purify the heavy metal in wastes and environment. (3)The phase fruit of experimental study that EM a new kind of microorganism material purify the mercury wastewater shows, mercury can poison EM, EM have tolerance and adaptability for mercury (tolerance 5mg/L Hg"+ at least, adapt 2.5mg/L Hg2+ with 8d, adapt 1.25mg/L Hg2+ with 2d) . The experimental study is a fundamental work for exerting and digging the potential of EM in biological treatment and harnessing for heavy metl pollution more.