IMPACT OF SODIUM AND POTASSIUM ON ENVIRONMENTAL SYSTEMS

Health effects associated with sodium-cycle water softening has led to the consideration of potassium-cycle ion exchange as an attractive al ternative. Regulatory agencies, however, have expressed concern regard ing the environmental impacts associated with discharge of potassium-l aden brine. To assist in providing guidance regarding the relative env ironmental impacts deriving from discharge of sodium- and potassium-cy cle softener regeneration brine, this article summarizes available lit erature exploring systems potentially impacted by brine discharge. The literature indicates that replacing sodium chloride with potassium ch loride as a water softener regenerant appears to result in a more envi ronmentally benign scenario and may, in certain circumstances, be envi ronmentally beneficial. Some areas where potassium chloride may be adv antageous are land application of sewage sludge, viral inactivation, m obility in soil, effects on soil properties and impacts on plant life. There are no significant differences between sodium chloride and pota ssium chloride in effect on engineered physicochemical processes of in inaquatic life systems. The impact of sodium may be detrimental to th e environment because the uptake of phosphorus by algae was reportedly enhanced by sodium. Potassium, on the other hand, was not reported to enhance phosphorous uptake. Some questions remain about the impact of potassium and sodium on septic tank bacteria, biological waste treatm ent processes, and effects on natural flora. The literature reviewed o n these topics was somewhat conflicting. Further efforts to assess the impact of potassium and sodium should be directed at resolving these literature discrepancies.