重金属离子对有效微生物群处理污水能力的影响

Effect of Heavy Metals on the Ability of Effective Microorganisms (EM) Purifying Domestic Sewage

在生活污水中添加不同种类不同体积质量的重金属离子， 研究了重金属离子对有效微生物群（Ｅｆｆｅｃｔｉｖｅ Ｍ ｉｃｒｏｏｒｇａｎｉｓｍ ｓ，简称ＥＭ ）去除生活污水化学需氧量（ＣＯＤｃｒ）的影响．结果表明：重金属对ＥＭ 有毒害作用，且体积质量越高，毒害作用越大；当其它条件保持不变时，ＣＯＤｃｒ 的去除率随重金属离子体积质量的增加而逐渐减少；另外，不同的重金属离子对ＥＭ 的降解能力影响也不同，其中，Ｈｇ２＋ ，Ａｓ３＋ 的毒性最大，Ｚｎ２＋ ，Ｐｂ２＋ 的毒性最小；ＥＭ 对污水中重金属离子的耐受体积质量分别是，对 Ａｓ３＋ 的耐受体积质量为０． ０５ ｍ ｇ ·Ｌ－ １， Ｈｇ ２＋ 为 ０． １０ ｍ ｇ · Ｌ－ １， Ｃｕ２＋ 为 ０． ５０ ｍ ｇ ·Ｌ－ １， Ｃｒ６＋ 为 ０． ５０ ｍ ｇ ·Ｌ－ １， Ｃｄ２＋ 为 ０． ５０ ｍ ｇ ·Ｌ－ １， Ｚｎ ２＋ 为１．００ ｍ ｇ·Ｌ－ １，Ｐｂ２＋ 为１．００ ｍ ｇ·Ｌ－ １．总之，用ＥＭ 处理生活污水时。

In this paper, the effect of heavy metals on the ability of Effective Microorganisms(EM) purifying domestic sewage was studied by adding 7 kinds of solutions containing different contents of Cu 2+ ,Zn 2+ ,Pb 2+ ,As 3+ ,Cr 6+ ,Cd 2+ and Hg 2+ to sewage.The results showed that every kind of heavy metal could poison EM ,and the higher the concentration of heavy metals in domestic sewage, the more serious the poisoning. When other conditions were given, the removal rate of CODcr was gradually reduced with the increase of heavy metals' concentration. In addition, each heavy metal had its own extent of effect on the ability of EM. Among 7 heavy metals, As 3+ and Hg 2+ had the strongest toxicity to EM; however, Zn 2+ ,Pb 2+ had weaker toxicity than others. The tolerance of EM to heavy metals were listed as follows: Cu 2+ 0.10 mg·L -1 ; Zn 2+ 1.0 mg·L -1 ;Pb2+ 1.0 mg·L -1 ;As3+ 0.05 mg·L -1 ;Cr 6+ 0.5 mg·L -1 ; Cd 2+ 0.5 mg·L -1 ;Hg 2+ 0.1 mg·L -1 . Generally, it is quite necessary to maintain lower concentrations of heavy metals in domestic sewage before using EM to purify it.