Journal of Global Ecology and Environment 2(4): 221-226, 2015
International Knowledge Press www.ikpress.org
NEUTRALIZATION OF DYEING INDUSTRY WASTEWATER AND SLUDGE BY FIXATION OF POLLUTANTS IN VERY HIGH QUALITY HEU-TYPE ZEOLITIC TUFF ANESTIS FILIPPIDIS1*, GEORGIOS PAPASTERGIOS1, NIKOLAOS KANTIRANIS1 AND SAWAS FILIPPIDIS1 1
Department of Mineralogy-Petrology-Economic Geology, School of Geology, Faculty of Sciences, Aristotle University, GR-54124 Thessaloniki, Greece.
AUTHORS’ CONTRIBUTIONS This work was carried out in collaboration between all authors. Author AF designed the study, wrote the protocol and interpreted the data. Author GP managed the literature, the chemical analyses and produced the initial draft. Author NK performed the mineralogical analyses, gathered the data and performed the data analysis. Author SF performed the experiments. All authors read and approved the final manuscript.
Received: 31st May 2015 Accepted: 27th June 2015 Original Research Article Published: 9th July 2015 __________________________________________________________________________________ ABSTRACT Treatment of dyeing industry wastewater of pH 7.5 with very high quality zeolitic tuff and coagulants, resulted in clear water of pH 7.2, free of odours and improved quality characteristics (colour, suspended particles, COD: Chemical Oxygen Demand, P2O5, NO3-, Cr) by 74 to 98%. The very high quality zeolitic tuff is 3 to 60% more effective than the coagulants, concerning COD, Cr and NO3-. The treatments produced sludge (using coagulants) and zeo-sludge (using very high quality zeolitic tuff and coagulants). The zeo-sludge is odourless and cohesive. The leaching by deionised water of sludge reached values up to 100% for the quality characteristics, while that of the zeo-sludge reached significantly lower values (only up to 18%). The chemical composition of the seepage water from the zeo-sludge proved the fixation of pollutants, such as NO3- and Cr by the very high quality zeolitic tuff. Keywords: HEU-type zeolite; zeolitic tuff; dyeing industry wastewater; dyeing industry sludge; fixation; safe deposition.
1. INTRODUCTION Zeolitic tuff is the rock which contains one or more from the different (>65) phases of zeolites. Zeolites are microporous, aluminosilicate solid crystalline materials, with open structure and void space. The zeolite with numerous applications is the HEU-type zeolite (clinoptilolite-heulandite) that shows tabular crystals and contains micro/nano-pores in a
framework of channels with 10- and 8-member rings, in dimensions of 7.5x3.1 Å, 4.6x3.6 Å and 4.7x2.8 Å [1,2]. For industrial, environmental, agricultural and aqua-cultural uses, the recommended HEU-type zeolite content should be greater than 75 wt.%. The presence of fibrous zeolites (e.g., erionite, mordenite, roggianite, mazzite, scolecite, mesolite, natrolite, ferrierite) is inhibitory for the use of the zeolitic tuff. In humans and animals, inhaled or injected or
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Filippidis et al.; JOGEE, 2(4): 221-226, 2015
swallowed, fibrous zeolites (mainly erionite and mordenite, and to a lesser extent, roggianite and mazzite) were proved to be toxic, carcinogenic and highly pathogenic [3-5]. The zeolitic tuffs, depending on the HEU-type zeolite content, are ranked as a) 85% very high quality [6,7]. Very high quality HEU-type zeolitic tuffs, displays unique physical and chemical features and have a great variety of environmental, industrial, aquacultural and agricultural applications. Almost every dyeing industry area is served by wastewater treatment facilities that aim to treat dyeing industry wastewater and dispose the sludge in a safe manner using a variety of techniques (e.g., anaerobic, aerobic, coagulation/precipitation, composting) [8-20]. The aim of the present study was to evaluate the purification of dyeing industry wastewater by applying firstly a process only with coagulants (polyaluminium chloride, sodium aluminate, decoloring and polyelectrolyte) and then a process which combines both coagulants and zeolitic tuff of very high quality. The suitability for the safe deposition of the zeo-sludge produced was also investigated.
2. MATERIALS AND METHODS The zeolitic tuff sample used was supplied by the Company “GEO-VET N. Alexandridis & Co OE”. Petrographic investigation of the zeolitic tuff was performed on thin and polished thin sections. The morphology and the chemistry of the minerals were studied by Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), JEOL JSM840 equipped with a Link-AN 10000 EDS system. The mineralogical composition of the zeolitic tuff was determined by X-Ray Powder Diffraction (XRPD) method (PHILIPS PW1710 diffractometer with Nifiltered CuKa radiation). Clay mineralogy was identified from air-dried, glycolated and heat-treated oriented samples [13,20]. Combined methods of SEM-EDS (microanalyses), thermal treatment at 450ºC for 8 hours and XRPD [21] were applied for the distinction of the HEU-type zeolites of group I (clinoptilolite), group II (intermediate heulandite) and group III (heulandite). The ammonia ion exchange capacity (sorption ability) of the zeolitic tuff was measured by the Ammonium Acetate Saturation (AMAS) method [22]. The chemical composition (major and trace elements) of the zeolitic tuff was determined by the methods FUS-
ICP-OES (Fusion-Inductively Coupled PlasmaOptical Emission Spectrometry), TD-ICP-MS (Total Digestion-Inductively Coupled Plasma-Mass Spectrometry) and INAA (Instrumental Neutron Activation Analysis). The dyeing industry wastewater was treated at room temperature with very high quality zeolitic tuff of
