Galvanic Corrosion of Lead Solder in Copper Pipework

The galvanic corrosion potentials of thirty-eight different waters were measured on site, using 'Oliphant' corrosion cells, for lead-tin solder coupled to copper. A wide range in corrosion potential was found, and the chloride-sulphate ratio had the most significant effect on corrosion potential. Tests to reduce corrosion potentials by dosing sulphate, silicate, zinc and orthophosphate were carried out. Zinc dosing, especially in combination with ortho-phosphate, was the most effective treatment for all waters, but posed problems.
Contamination of tapwater by galvanic corrosion of lead solder occurs early in the life of new plumbing, and risk of exposure to contamination can be reduced by flushing before drawing dietetic water. Best-of-all, lead-tin solder should not be used.     

浅谈简易自来水在山区县农村的应用和设计

农村农药和化肥的大量使用,使地表水受到了严重污染,农村经济基础薄弱,饮水设施又十分简陋,这些造成了大量村民饮水困难。针对山区县农村人口分散的特点,采用建分散式简易自来水工程的方式来解决村民饮水困难的问题,并就简易自来水工程的组成和设计方法进行探讨。     

三种水质对煤沥青水浆制备及性质的影响

以中温煤沥青为原料,采用冷冻粉碎方法制得具有一定粒度级配的煤沥青粉后,再加入适量分散剂与去离子水、自来水和焦化废水分别制备煤沥青水浆.考察了分散剂用量与煤沥青水浆流变性的关系,并对分散剂在煤沥青表面的吸附和Zeta电位进行了研究.研究表明,三种水均能制得浆体浓度为70%的煤沥青水浆,且浆体的表观黏度均随剪切速率的增加呈下降趋势.由去离子水、自来水和焦化废水制得煤沥青水浆的低位发热量、挥发分和灰分均达水煤浆Ⅰ级标准,硫分达Ⅱ级标准.三种水的分散剂溶液在煤沥青表面的吸附量和Zeta电位均随分散剂浓度的增加呈增大趋势,当分散剂浓度达到一定值后继续增加分散剂的浓度,吸附量和Zeta电位稍有下降,且吸附量和Zeta电位达到最大时对应的分散剂浓度基本相同.     

黄河自来水混凝预处理的研究

针对黄河自来水的水质状况,试验采用混凝+机械过滤工艺预处理黄河自来水。通过单因素变量分析及正交混凝试验,以COD和浊度作为混凝效果的参照指标,试验确定了最佳混凝工艺:PAM最佳用量0.15 mg/L,PAC用量3.0 mg/L,混凝时间8 min,过滤速度8 m/h,其产水水质稳定并处理量较大。