Chemical properties of coal bed methane product water in Qinshui Basin in China

The objective of this study was to examine the chem ical properties of CBM product water at discharge sand in associated impoundments across the Qinshui Basin. R esults show that TDS, pH and Total Alkalinity of pr oduct water for three areas increased in impoundments com pared with discharge sites. The CBM product water e relatively less change in ion and element concentra tions in Zhengzhuang impoundments, however, the dis solved F concentration increased in Shizhuang impoundments. Due to cation exchange and precipitation, concentra tions of HCO 3 - , Ca 2+ and Mg 2+ of product water increased considerably but concen tration of K + +Na + and CO 3 2- of product water decreased considerably in impoundment waters of Shizhuang and Guxian areas, concentration of Cl - , SO 4 2- , NH 4 + and dissolved Fe, Zn and Mn of product water showed less change in impoundment water of three areas. Dissolved As, Cu, Pb and Cd concentrations were non -detectable in both CBM discharge site and associat ed pond waters of the three areas.