THE EFFECTS OF NATURAL ZEOLITE ON STORMWATER MANAGEMENT

Heavy metals from tires, automobiles exhausts, road asphalt, a fuel combustion wash into urban stormwater runoff and its discharge into water sources, which results in public health and environmental hazards (Reddy et al., 2014). When stormwater contaminated with heavy metals are discharged into the environment, non-biodegradable metals can accumulate and cause significant health conditions in humans and animals including damage to the central nervous system, lungs, and digestive system. Over the past several decades, scientists have examined treatment methods that remove pollutants from urban stormwater. Adsorption is a favored process that involves physical and chemical processes; it removes dissolved metal ions from liquid wastes in a cost effective and convenient manner.

Because of zeolite’s significant adsorption capacity, its application in water treatment processes is a promising technique in the environmental cleaning process (Wang & Peng, 2010). The utilization of natural zeolites has focused on the removal of ammonium and heavy metals through ion exchange. Zeolite can provide a low-cost solution to water treatment processes, as the minerals are less expensive when compared to commercial sorbents like activated carbon.

A study by Reddy et al. (2014) examined how permeable filter systems consisting of adsorptive media can be used to remove pollutants, particularly from urban environments. The study investigated the potential of zeolite, calcite, sand, and iron filings to adsorb and remove heavy metals from stormwater run-off. The findings indicated that the maximum removal of heavy metals by zeolite were: 95 – 100 percent for cadmium, lead, zinc, and copper; 90 percent for nickel. No one single mineral used in the filter system was capable of removing all metals, but a combination of all filter minerals was deemed effective for the simultaneous removal of contaminants.

Smith et al. (2004) examined the impact of zeolite filters on ammonia nitrogen removal from stormwater. A water sample was collected from a pond and supplied with a zeolite-packed filter that operated at a 0.9 hour detention time for 57 days. After three weeks, nitrate and nitrite concentrations declined and minimal ammonia breakthrough was observed from the filter. The results indicate that zeolite filtration removes ammonia from stormwater. Potential applications of zeolite filters include in-ground or above- ground filtration of residential runoff, side bank filtration from stormwater detention ponds, and filtration of parking lot and roadway runoff (Smith et al., 2004).

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