Petroleum wastewater: Environmental protection, treatment, and safe reuse: An overview.

Oil petroleum production consumes about 1.0-7.2 bbl. The needed water for such production ranges between 0.47 and 7.2 L water to 1.0 L crude. Between 80 and 90% of the consumed water is disposed of as wasted effluents. Consequently, there is an important connection between petroleum production and the contamination of the environment and surface water in addition to their ecotoxicological effects. The objective of the present review is to through light on the hazardous impact of petroleum wastewater on the environment and water ways. The present study presents several wastewater treatment technologies in handling the petroleum produced water (PPW) and reducing the hazardous impact to the environment. Safe reuse is also presented including simple, advanced, and environmentally friendly techniques. The reported treatment technologies are divided into five main categories: membrane technologies, biological treatment processes, electro-chemical coagulation, physical/chemical treatment processes (dissolved air flotation (DAF)/air flotation (IAF), adsorption, and chemical flocculation), and catalytic oxidation including chemicals such as advanced and Fenton oxidation processes (AOPs). The analysis and observation of each treatment process are also presented. Implementing of these processes in sequential and/or in combined to avoid the drawbacks of any poor treatment are discussed. The present review discusses; also, in detail each of these treatment technologies and their efficiency including the observation and conclusions of each one. The study shows; also; how the final treated effluent can be reused for non-potable purposes as an additional water resource according to the degree of decontamination. An additional advantage of treatment is protection of both the environment and the water ways by avoiding any discharge of such hazardous wastewater.

Treatment of leather industrial wastewater via combined advanced oxidation and membrane filtration.

The liming/unhairing operation is among the important processes of the leather industry. It generates large amounts of effluent that are highly loaded with organic hazard wastes. Such effluent is considered one of the most obnoxious materials in the leather industry, causing serious environmental pollution and health risks. The effluent is characterized by high concentrations of the pollution parameters. Conventional chemical and/or biological treatment of such wastewater is inefficient to meet the required limits of standard specifications, due to the presence of resistant and toxic compounds. The present investigation deals with an effective treatment approach for the lime/unhair effluent using the Fenton reaction followed by membrane filtration. The experiment was extended to a laboratory pilot-scale in a continuous treatment study. In this study the raw wastewater was treated with the predetermined Fenton's optimum dose followed by membrane filtration. The wastewater was efficiently treated and the final effluent met the standards for unrestricted water reuse.

Anaerobic/aerobic treatment of greywater via UASB and MBR for unrestricted reuse.

The aim of the present study was to investigate the efficiency of integrated up-flow anaerobic sludge blanket (UASB) as anaerobic system followed by membrane bioreactor (MBR) as aerobic system for the treatment of greywater for unrestricted reuse. Pilot-scale UASB and MBR units were installed and operated in the NRC, Egypt. Real raw greywater was subjected to UASB and the effluent was further treated with microfiltration MBR. The necessary trans-membrane pressure difference is applied by the water head above the membrane (gravity flow) without any energy input. The average characteristics of the raw greywater were 95, 392, 298, 10.45, 0.4, 118.5 and 28 mg/L for total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphates, nitrates, oil and grease, and total Kjeldahl nitrogen (TKN), respectively. The pH was 6.71. The UASB treatment efficiency reached 19.3, 57.8, 67.5 and 83.7% for TSS, COD, BOD5 and oil and grease, respectively. When the UASB effluent was further treated with MBR, the overall removal rate achieved 97.7, 97.8, 97.4 and 95.8% for the same parameters successively. The characteristics of the final effluent reached 2.5, 8.5, 6.1, 0.95, 4.6 and 2.3 mg/L for TSS, COD, BOD, phosphates, oil and grease and TKN, respectively. This final treated effluent could cope with the unrestricted water reuse of local Egyptian guidelines.