On-line Process Monitoring in a Liquid Waste Treatment Facility Using Ion Chromatography

On-line monitoring of process and wastewater streams optimizes the control of treatment methods by providing early indications of problems that could increase discharges of hazardous compounds to the environment. On-line monitoring is important for the immediate detection and remediation of process upsets in critical streams. The waste flow to the Radioactive Liquid Waste Treatment Facility (RLWTF) at the Los Alamos National Laboratory (LANL) is processed before discharge and requires monitoring. Process chromatography is used to monitor trends of contaminants in real time. The purpose of this study is to develop an automated on-line chromatography procedure for the simultaneous determination of anions in LANL wastewater. INTRODUCTION Waste management programs are occasionally concerned with the various compounds of nitrogen, due to the effects that nitrogeneous compounds can have on the environment. Trace quantities of nitrates are found in surface waters, but high quantities of nitrates maybe found in some groundwaters. At LANL, a 10 mg/L nitrate as nitrogen has been imposed on drinking water to prevent methemoglobinemia. The use of nitric acid throughout the LANL complex produces the nitrates in the plant influent discharged to Mortendad Canyon. The extensive use of fertilizers and improper disposal of wastewater are the primary cause of the nitrate problem in New Mexico. The RLWTF treats industrial and radioactive liquid wastes generated at multiple research and production facilities across the LANL (Fig.1). This facility processes about 28,000 gal/day of wastewater. Waste is collected and treated to reduce radioactive contamination to levels that meet the limits specified in the National Pollutant Discharge Elimination System (NPDES) permit and the Department of Energy (DOE) orders. The permit is administered by the New Mexico Environmental Department (NMED) and requires LANL to meet the drinking water limit for nitrates. The RLWTF perform chemical and physical separation processes to concentrate radioactive constituents in a sludge that is dewatered to 30 percent solids. The solidified sludge, depending on radionuclide concentration, is either disposed of as LLW or stored as TRU wastes. WM’00 Conference, February 27 – March 2, 2000, Tucson, AZ Fig.1. LANL Radioactive Liquid Waste Collection System (RLWCS) TA-3 TA-3 South Mesa Site