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4119442 
Journal Article 
Control concrete sewer corrosion via the crown spray process 
Sydney, R; Esfandi, E; Surapaneni, S 
1996 
1 
Water Environment Research
ISSN: 1061-4303
EISSN: 1554-7531 
BIOSIS/96/34775 
68 
3 
338-347 
English 
BIOSIS COPYRIGHT: BIOL ABS. The crown spray process involves the spray application of a high-pH mixture to the crown area of the sewer. The aim is to deactivate the sulfur- or sulfide-oxidizing bacteria (SOB) and neutralize the acid at the sewer crown; to render the sewer crown environment unfavorable for regrowth and recolonization of SOB; to leave a residual alkalinity on the sewer crown to neutralize the acid produced as the SOB recolonize the sewer, and, consequently, control the crown corrosion process. A number of different chemicals, both hazardous and nonhazardous, were investigated for use with the process. The use of biocides as additives to enhance the deactivation potentials of the various treatment mixtures was also evaluated. To gauge the effectiveness of the treatment, surface pH of the sewer crown is measured before and after treatment. Immediately after spraying the surface, pH of the crown generally increases from less than 2 to greater than 9 and then gradually decreases with ti