Treatment of oil–water emulsion from the machinery industry by Fenton's reagent

Abstract

An oil-water emulsion from the machinery industry was treated using Fenton's reagent. The objective was to reduce the high chemical oxygen demand (COD) of this waste stream so that it would meet the COD effluent limit of Chinese Standard JS-7740-95. The optimal [H2O2]/[Fe2+] ratio for COD removal was 3. An orthogonal experimental design was developed based on the optimal [H2O2]/[Fe2+] ratio to evaluate the significance of four parameters relevant to the treatment process, namely, H2O2 dosage, initial pH, oxidation time and coagulation pH. The influence of the four parameters on COD removal efficiency decreased as follows: H2O2 dosage>oxidation time>coagulation pH>initial pH. The COD removal efficiency was further investigated based on the most important single-factor parameter, which was H2O2 dosage, as discovered in the orthogonal test. A well-fitted empirical correlation was obtained from the single-factor analysis and up to 98% COD removal was attained using 50 mM H2O2. Using the doses and conditions identified in this study, the treated oil-water emulsion can be discharged according to Chinese Standard JS-7740-95.

Treatment of microfiber alkali weight‐reduction wastewater with high salt concentration by Fenton oxidation and bacterial degradation

“…The COD was measured using spectro‐photometric according to the Chinese Standard HJ/T 399‐2007 (Feng et al , 2015). Samples were digested at 165°C for 10 min by COD special reagents (Chengdu Lianhua environmental protection technology co. LTD) with 5B3A COD rapid digestion device.…”

In situ treatment of metalworking wastewater by chemical addition-dissolved air flotation coupled with UV, H2O2 & ZnO

“…However, thanks to the consequences of thermal deterioration, particulate contamination, and biological contamination, it is needed that these emulsion fluids be replaced periodically. Thus, an awful lot of hazardous liquid is generated, which involves purification [16].…”

“…Since the each of biological treatment approaches needs a strong concentration of organic substances along poor low molecular weight and BOD to COD proportion more than 0.4 (a standard rate), the toxicity of these fluids is a downside for applying these processes as a pretreatment or even single treatment [8,9,10]. The Ozone-based advanced oxidation processes (AOPs) [29], heterogeneous photo-catalysis by applying semiconductors as TiO 2 [30], ZnO as well as homogenous processes such as Fenton reaction have advantage of the fast oxidation of pollutants to harmless end products especially when is motivated by ultraviolet (UV) radiation [9,16,25]. Recently, combining processes as hybrid techniques for MWF wastewater treatment has been investigated by many researchers such as incorporating biodegradation and advanced oxidation process [13], hybrid biological, electron beam and zero-valent Nano iron [28], the DAF followed with the photo-Fenton process and other DAF-based hybrid approaches [8,22,31].…”

Improve the Catalytic Activity of Feooh/Bentonite Material by Mechanical Activation

“…Even through Fenton oxidation is an effective technology to treat the wastewater containing recalcitrant organic pollutants, some drawbacks existing in conventional homogeneous Fenton system have prevented the wide industrialization of Fenton oxidation in wastewater treatment 1,2 . In order to overcome the drawbacks, heterogeneous catalysts used in Fenton system have aroused attention of the researchers.…”