SULFIDE PRODUCTION AND WASTE-WATER QUALITY IN PRESSURE MAINS

An empirical model for predicting sulfide production in pressure mains (Hvitved-Jacobsen et al., 1988) was evaluated and modified based on r esults obtained from two intercepting pressure mains located in the No rthern part of Jutland, Denmark. Mass balances in pipe influent and ef fluent were made for volatile fatty acids, VFA (formate, acetate, prop ionate and butyrate), dissolved COD, DOC and sulfide and biofilm surfa ce rate for sulfide and organic matter were calculated. Relatively hig h sulfide formation rates were observed at low temperatures (5-12 degr ees C). The sulfide production rate strongly depended on wastewater qu ality in terms of VFA and dissolved carbohydrate concentration. Based on these two sets of observations wastewater quality and temperature - the original empirical model was modified. (C) 1998 IAWQ. Published b y Elsevier Science Ltd.