مقاله انگلیسی رایگان در مورد غلیظ کردن فاضلاب کارخانه ملاس – الزویر 2018

Sugarcane molasses based alcohol distilleries in India are one of the most water intensive and polluting industrial sectors with a fresh water consumption of about 9e21 L/L alcohol and wastewater generation of 7e15 L/L alcohol (GoI, 2014). The wastewater has a very high organic load, low pH, high total dissolved solids, unpleasant odor and dark brown color. A major cause of color is melanoidins, a product of Maillard reaction between reducing sugars and amino acids, which constitutes 2% (w/v) of the wastewater (Arimi et al., 2014; Yadav and Chandra, 2012). Melanoidins are characterized by complex structure, possess antioxidant properties and are not readily biodegradable. The presence of these compounds deters biological treatment and color removal in distillery wastewater poses a major challenge. On the other hand, its antioxidant properties can be exploited in applications like food preservation and personal care products. Considering the stringent regulations imposed by the Central Pollution Control Board (CPCB) on fresh water consumption (maximum of 15 L/L of alcohol production) and zero liquid discharge (ZLD) from distilleries, alternatives to existing treatment options like anaerobic digestion, incineration and reverse osmosis continue to be of interest. As fresh water is required for various non-process applications like steam generation, cooling tower make-up water, washing of fermenters, distillation units, floors etc., appropriately treated wastewater offers potential for reuse. Furthermore, antioxidant components in distillery wastewater could be an additional value added resource that could be recovered. Forward osmosis (FO) is a membrane based separation process operating on osmotic pressure difference between the low osmotic pressure feed solution and the high osmotic pressure draw solution separated by a semi-permeable membrane. In combination with other membrane separation processes like reverse osmosis, membrane distillation and microfiltration, FO has been used for treatment of various complex wastewaters to either enrich the feed in trace components by reducing the feed volume or to reclaim the wastewater for direct potable reuse. Examples of such applications include (i) selective removal of pharmaceutical micropollutants (carbamazepine, diclofenac, ibuprofen and naproxen) from synthetic feed (Madsen et al., 2015; D’Haese et al., 2013; Jin et al., 2012; Xie et al., 2012; Hancock et al., 2011; Linares et al., 2011); (ii) dewatering drilling wastewater from oil and gas exploration (Hickenbottom et al., 2013); (iii) treatment of domestic wastewater in osmotic membrane reactor (OMBR) (Zhang et al., 2012a, 2014; Alturki et al., 2013, 2012b; Cornelissen et al., 2010; Achilli et al., 2009); (iv) treatment of municipal wastewater (Hey et al., 2016a, 2017, 2016b); (v) nutrient recovery from domestic wastewater (Devia et al., 2015); (vi) upgrading rain water to replace fresh water for cooling water make-up in steam plant (Wang et al., 2014). In most of the above-listed applications, cellulose triacetate (CTA) and thin film composite (TFC) commercial FO membranes were used. CTA membrane was compared with newly developed biomimetic aquaporin membrane for rejection of three trace organics. Partial rejection was reported with CTA membrane whereas over 97% rejection was obtained with aquaporin membrane (Madsen et al., 2015). CTA and TFC membranes were also tested along with aquaporin membranes for municipal wastewater treatment (Hey et al., 2016a, 2016b). Biomimetic FO membranes have been largely studied for desalination (Grzelakowski et al., 2015; Tang et al., 2013) where high water flux (~20 L/m2 h) and high salt rejection (~97%) have been obtained at 5 bar (Zhao et al., 2012).