Treatment of high salt oxidized modified starch waste water using micro-electrolysis, two-phase anaerobic aerobic and electrolysis for reuse

Abstract

A combined process of micro-electrolysis, twophase anaerobic, aerobic and electrolysis was investigated for the treatment of oxidized modified starch wastewater (OMSW). Optimum ranges for important operating variables were experimentally determined and the treated water was tested for reuse in the production process of corn starch. The optimum hydraulic retention time (HRT) of micro-electrolysis, methanation reactor, aerobic process and electrolysis process were 5, 24, 12 and 3 h, respectively. The addition of iron-carbon fillers to the acidification reactor was 200 mg/L while the best current density of electrolysis was 300 A/m 2 . The biodegradability was improved from 0.12 to 0.34 by micro-electrolysis. The whole treatment was found to be effective with removal of 96 % of the chemical oxygen demand (COD), 0.71 L/day of methane energy recovery. In addition, active chlorine production (15,720 mg/L) was obtained by electrolysis. The advantage of this hybrid process is that, through appropriate control of reaction conditions, effect from high concentration of salt on the treatment was avoided. Moreover, the process also produced the material needed in the production of oxidized starch while remaining emission-free and solved the problem of high process cost.

Ultrasonic treatment improves the performance of starch as depressant for hematite flotation

“…In the literature, there are several physical and chemical methods available for the dissolution of starch, including high pressure microwave vessel method and oxidation, etc. The former method requires harsh dissolution conditions (such as high pressure and high temperature) to obtain complete dissolution of starch [13] , while the latter produces a large amount of NaCl during the oxidized modification process in the wastewater with high treatment difficulty [14] . It is worth noting that recently, Fletcher, et al [15] reported that starch after oxidization allowed greater recovery of chalcopyrite in the presence of graphite or copper-activated pyrite as gangue, pointing to selectivity potential.…”