Effect of Electronic Water Treatment System on Calcium Carbonate Scale Formation in Landfill Leachate Collection Piping

Abstract

Clogging of leachate collection systems (LCSs) can cause potentially catastrophic failures in landfill operation. The primary cause of clogging is calcium carbonate precipitation, which forms inside the pipe around a nucleus of silt, sand, microbial colonies, or other particles. One approach that has been proposed to prevent clogging in LCS is electronic scale control (ESC) technology. To quantify the effectiveness of ESC to reduce clogging within a gravity LCS pipe network, a field-scale pipe network was constructed with side-by-side flow of composite leachate treated electronically on one side and untreated leachate on the other. Water quality parameters, saturation indices, and solids composition were compared for any differences between the treated and untreated leachate. With respect to water quality of leachate, no statistically significant differences were observed. Neither the Langelier Saturation Index (LSI) nor the Ryzner Index (RI) changed toward neutrality after treatment. X-ray diffraction/X-ray fluorescence (XRD/XRF) analysis of precipitates in the pipe network identified calcite (CaCO3) to be the predominant phase present, and there were no observed differences in composition between the treated and untreated precipitates.