MICROWAVE ENHANCED CHROMIUM EXTRACTION FROM SEWAGE SLUDGE AND SOIL-SLUDGE MIXTURES USING BIODEGRADABLE CHELANTS

Microwave enhanced chromium extraction from sewage sludge and soil-sludge mixtures was carried out using ethylenediaminetetraacetic acid (EDTA) more biodegradable chelating agents: methyleneglycinediacetic (MGDA), S, S’-ethylenediaminedisuccinic (EDDS) S-carboxyl-L-cysteine (SCLC). Raising the temperature microwave energy had particularly strong effect on Cr efficiency with MGDA all investigated biosolids. The higher temperature, larger amount of metal extracted – maximum removal at 150oC 38 times than that 20oC. microwave-assisted duration also significant effectiveness increased by 40-60 % while increasing 15 min up to 60 min, depending upon type biosolid tested. MW-enhanced mixture clay soil in cases significantly lower raw samples as well sandy soil. Extraction study showed such readily degradable agents EDDS can be successfully used wash biosolids presence contamination instead persistent EDTA when is applied, SCLC less efficient. According complexation efficiency, chelants ranked following order: EDTA≈MGDA>EDDS>SCLC, overall capacity better EDDS.