Treatment of real wastewater produced from Mobil car wash station using electrocoagulation technique

Techno-environmental study on the consequences of carwash wastewater and its management methods

Carwash wastewater (CWW) is an important source of environmental pollution. The aim of this study was to investigate the characteristics of CWW and technical comparison of its treatment methods. For this purpose, a systematic search was conducted and after three stages of screening the found articles, finally 30 articles were selected for this review. The results showed that due to the differences in the type of washing, the geological condition, the type of car, and the climatic conditions, the CWWs have temporal and spatial variation in the concentration of pollutants. However, the most important pollutants of CWW include oil, suspended solids, detergents, and organic compounds. The most widely used methods in CWW treatment in the main stages included chemical coagulation and electrocoagulation, which reduce turbidity by more than 90% and COD by more than 50% in the best efficiency. Also, membrane technology was a common method in CWW treatment systems to achieve proper effluent quality. COD reduction by ultrafiltration, nanofiltration, microfiltration, and reverse osmosis was 95-77%, more than 90%, 81-73%, and 87%, respectively. The efficiency of membrane technologies in reducing turbidity was often more than 90% and in few cases more than 50%. Sludge production in the coagulation process, energy consumption in electrochemical processes, and the low water recovery rate in membrane processes are important challenges in CWW treatment that must be managed by modifying the process or using combined methods.

A Review of On-Site Carwash Wastewater Treatment

In recent years, people’s environmental awareness has increased. The high density of the urban population has caused a considerable increase in the demand for car washing services, which has created large quantities of car wash wastewater. The main pollutants in car wash wastewater are detergents, dirt, oil, and grease. Untreated wastewater released into rainwater sewer systems or other water bodies may pollute the water and generate excessive bubble foams, which negatively affects urban appearance. Car washes are divided into mechanical car washes and manual or self-service car washes. In general, car washes have a small operation and scale, occupy limited land, and cannot afford wastewater treatment costs. Therefore, most car washes are not equipped with wastewater treatment facilities. Consequently, the discharge of wastewater from car washes negatively affects the water quality in the surrounding environment and results in wasteful use of water resources. This study reviewed 68 research papers on the quality, treatment techniques, treatment costs, and treatment effectiveness of car wash wastewater to provide a reference for car wash operators to contribute to the preservation of water resources. We found that there is a higher chance of recycling car wash wastewater when combing two different techniques for car wash wastewater treatment.

Efficient technologies for carwash wastewater treatment: a systematic review

Carwash wastewater (CWW) is considered as an important source of either water pollution or water consumption. Therefore, its treatment is critical not only from the prevention of environmental contamination but also from the recycling of such high-volume water source. Unfortunately, the effective treatment of CWW is almost unknown, complex, and expensive. To overcome the former challenge, this study aimed to systematically review different technologies for CWW treatment. For this, a comprehensive literature survey was conducted and 48 research articles were found suitable to be included in the investigation. The included studies were of coagulation and adsorption (n = 5), membrane-based technologies (n = 15), and electrochemical (n = 11) and combined (n = 17) systems. This comprehensive review showed that the treatment methods of advanced filtration membrane techniques, electrical and chemical coagulation, and advanced oxidation processes can be effective in the removal of pollutants from carwash wastewater (CWW). The mining of different studies, however, showed that the combined methods are the most promising option in the remediation of such wastewater.

Post-treatment of paint industry effluents by filtration using Andropogon biochar (Andropogon gayanus Kunth cv. Planaltina)

This study evaluates the filtration potential of the biomass obtained from Andropogon grass (Andropogon gayanus Kunth cv. Planaltina) that was converted to biochar by pyrolysis. The biochar is used in filtration systems for the post-treatment of paint industry effluents. The biomass is characterized by elemental analysis (CHSN-O), determination of specific compounds (cellulose/hemicellulose/lignin), FTIR, and SEM. The produced biochar is characterized by SEM, TGA, and surface area analysis. The efficiency of the filters is evaluated by the following parameters: color, turbidity, removal of total solids (suspended and sedimentable), chemical oxygen demand (COD), and metals (Al, Cu, Zn, Co, Cd, and Cr(VI)). Over 99% removal of aluminum, cadmium, and hexavalent chromium is achieved. Moreover, almost 100% of COD and solids are removed, whereas turbidity and color are reduced by over 90%.

Membrane bioreactors and electrochemical processes for treatment of wastewaters containing heavy metal ions, organics, micropollutants and dyes: Recent developments

Research and development activities on standalone systems of membrane bioreactors and electrochemical reactors for wastewater treatment have been intensified recently. However, several challenges are still being faced during the operation of these reactors. The current challenges associated with the operation of standalone MBR and electrochemical reactors include: membrane fouling in MBR, set-backs from operational errors and conditions, energy consumption in electrochemical systems, high cost requirement, and the need for simplified models. The advantage of this review is to present the most critical challenges and opportunities. These challenges have necessitated the design of MBR derivatives such as anaerobic MBR (AnMBR), osmotic MBR (OMBR), biofilm MBR (BF-MBR), membrane aerated biofilm reactor (MABR), and magnetically-enhanced systems. Likewise, electrochemical reactors with different configurations such as parallel, cylindrical, rotating impeller-electrode, packed bed, and moving particle configurations have emerged. One of the most effective approaches towards reducing energy consumption and membrane fouling rate is the integration of MBR with low-voltage electrochemical processes in an electrically-enhanced membrane bioreactor (eMBR). Meanwhile, research on eMBR modeling and sludge reuse is limited. Future trends should focus on novel/fresh concepts such as electrically-enhanced AnMBRs, electrically-enhanced OMBRs, and coupled systems with microbial fuel cells to further improve energy efficiency and effluent quality.

Treatment of paint manufacturing wastewater by coagulation/electrochemical methods: Proposals for disposal and/or reuse of treated water

This paper describes and discusses an investigation into the treatment of paint manufacturing wastewater (water-based acrylic texture) by coagulation (aluminum sulfate) coupled to electrochemical methods (BDD electrode). Two proposals are put forward, based on the results. The first proposal considers the feasibility of reusing wastewater treated by the methods separately and in combination, while the second examines the possibility of its disposal into water bodies. To this end, parameters such as toxicity, turbidity, color, organic load, dissolved aluminum, alkalinity, hardness and odor are evaluated. In addition, the proposal for water reuse is strengthened by the quality of the water-based paints produced using the wastewater treated by the two methods (combined and separate), which was evaluated based on the typical parameters for the quality control of these products. Under optimized conditions, the use of the chemical coagulation (12 mL/L of Al2(SO4)3 dosage) treatment, alone, proved the feasibility of reusing the treated wastewater in the paint manufacturing process. However, the use of the electrochemical method (i = 10 mA/cm(2) and t = 90 min) was required to render the treated wastewater suitable for discharge into water bodies.