MWRA是美国联邦43个社区的未过滤地表水批发商 马萨诸塞州。目前的处理方法包括用次氯酸钠进行一次消毒。这是 随后在下游约5小时添加苏打灰、二氧化碳和氟化物。氯气是 在苏打灰下游约10小时处添加氨水进行残余消毒 附加 MWRA的水源水pH值和碱度通常低于7.2，碳酸钙为5 mg/L， 分别地添加纯碱和二氧化碳主要是为了控制腐蚀 来解决铅和铜的规则。铅和铜的含量都大幅下降，到了第90天 百分位铅水平徘徊在15 ppb左右。目前的操作目标是pH值9.1和 碳酸钙的碱度为35 mg/L。这种腐蚀控制方案的额外好处包括 废水生物固体中铜和铅含量降低，投诉减少 变色的水，以及可控的硝化水平。 本文主要研究缓冲容量增加对铁的影响之间的相互作用 释放以及铁释放与氯胺和pH稳定性以及氯胺稳定性的相互作用 以及硝化作用。该结果应适用于其他原水碱度和使用量较低的系统 氯胺用于残留消毒。 包括3个参考文献、图表。

MWRA is an unfiltered surface water wholesaler to 43 communities in the Commonwealth of Massachusetts. Current treatment includes primary disinfection with sodium hypochlorite. This is followed by soda ash, carbon dioxide and fluoride addition about 5 hours downstream. Chlorine gas is added followed by ammonia for residual disinfection about 10 hours further downstream from the soda ash addition. MWRA's source water pH and alkalinity are typically less than 7.2 and 5 mg/L as calcium carbonate, respectively. The soda ash and carbon dioxide addition was implemented for corrosion control, primarily to address the lead and copper rule. Both lead and copper levels have decreased tremendously and the 90th percentile lead level is hovering around the action level of 15 ppb. Current operating targets are pH 9.1 and alkalinity of 35 mg/L as calcium carbonate. Added benefits from this corrosion control scheme include decreases in both copper and lead levels in the wastewater bio-solids, decreases in complaints about discolored water, as well as manageable levels of nitrification. This paper focuses on the interactions between the effects of increased buffering capacity on iron release and the interaction of iron release with chloramine and pH stability, as well as chloramine stability and nitrification. The results should be applicable to other systems with low raw water alkalinity and use chloramine for residual disinfection. Includes 3 references, figures.