Dewatered anaerobically‐stabilized primary sewage sludge composting: Metal leachability and uptake by natural Clinoptilolite

Abstract

Environmental problems associated with sewage sludge disposal have prompted strict legislative actions over the past years. At the same time, the upgrading and expansion of wastewater treatment plants have greatly increased the volume of sludge generated. The major limitation of land application of sewage sludge compost is the potential high heavy metal content in relation to the metal content of the original sludge. Composting of sewage sludge with natural zeolite (Clinoptilolite) can enhance its quality and suitability for agricultural use. Clinoptilolite has the ability to uptake heavy metals in satisfactory levels. Finally, in order to estimate the metal leach ability of the final product of compost, the Generalized Acid Neutralization Capacity (GANC) procedure was used and was found that by increasing the leachate pH, the heavy metal concentration decreases.

Nutrient release from extracted activated sludge cells using the microwave enhanced advanced oxidation process

“…For ratios higher than 5, characteristic of fulvic acid are shown. [24,26,27] In a separate set of experiment aimed to distinguish humic acid from fulvic acid, the E4/E6 values for the sewage sludge, the extracted EPS, and the microwave treated samples were 2.3, 2.3 and 2.2, respectively. Therefore, humic substances reported in the Table 1 were most likely to be humic acids.…”

Effect of natural zeolite (clinoptilolite) on ammonia emissions of leftover food-rice hulls composting at the initial stage of the thermophilic process

“…Clinoptilolite is the most abundant source of natural zeolite and has the chemical formula Na (Galli et al, 1983). Earlier studies have shown that clinoptilolite, and certain other natural zeolites are effective in removing ammonia from wastewater (Emadi et al, 2001;Zorpas et al, 1999). However, there are few studies on the effects of natural zeolites on ammonia reduction during the thermophilic stage of food waste composting.…”

Removal of Cu(II) from leachate using natural zeolite as a landfill liner material

“…It has also found application in removal and purification of cesium and strontium radioisotopes. Natural zeolites nowadays are mostly used in catalysis, in air enrichment, as filters in paper and rubber industry, in soil benefication, as animal feed supplements, and in water and wastewater treatment [13].…”