###### Abstract  
This study presents a compact system developed to treat paint-industrial water contaminated by the residues of volatile organic compounds (VOCs) using hybrid electrothermochemical wastewater treatment technology. Different treatment parameters (sample dilution, working current) were studied, and the power of the removal was expressed by the removal efficiency factor. It was shown that for all of the VOCs, significant removal was obtained with dilution 1:3 (industrial water: deionized water, \(V\):\(V\)) and electric current set at 30 A. For advanced inspection of the treatment process, a simple and solventless method has been developed and validated, using headspace sampling combined with gas chromatography-mass spectrometry. Parameters affecting the headspace sampling efficiency were thoroughly studied, including the temperature, time, and mixing rate. The proposed method was partially validated utilizing the selected sampling parameters. The limits of detection ranged between 0.19 \(\mu\)g/L and 4.02 \(\mu\)g/L. The validated analytical method was an efficient tool for the inspection of residual VOCs in paint-industrial water and treated water samples. The new electrochemical water treatment was shown to be helpful in the paint industry's effluent reuse. industrial water; VOCs; electrothermal water treatment; headspace sampling; GC-MS +
Footnote †: journal: Applied Sciences  
and other pollutants, and also, environmental pollution can be involved in and associated with piping, improper waste disposal practices, and leaching landfills [3; 4]. Some of these pollutants are on the list of priority toxic substances by the US Environmental Protection Agency (US EPA) [5]. VOCs pose a serious threat to the ecosystem and human health due to their high toxicity and migration to groundwater [6]; they are chemically inert, with a relatively high ability to be dissolved in water, and are toxic. Therefore, VOCs are common targets of environmental monitoring [7]. The struggle with the local environment and diffuse pollution of the VOCs spills is an issue of wide interest. Developing efficient and useful wastewater treatment technologies is needed to meet the standards of rigorous environmental regulations [8]. For the elimination of volatile pollution, several treatment processes have been mentioned in the published materials, and many of them are currently used. These differ in many aspects and include processes from the most used and cost-effective to the most advanced and costliest ones [9]. The mostly applied process for the degradation of VOCs in water samples is microbe-mediated biodegradation, where microbes with specific functions act as degraders, and they transform VOCs into nontoxic compounds [10]. Many bacteria which should effectively degrade VOCs have been isolated in recent years, and biodegradation pathways have been explored [5]. However, there are still leaks in the VOC-degrading, strains and the main disadvantage of these techniques is that the biodegradation processes of VOCs take a long time, more than 48 h [8]. Therefore, biofiltration is considered the most important technology among biological treatment systems [11; 12]. Furthermore, this technology has been shown to be a low-cost technology to control pollution by odors and VOCs [13]. There are some applications of advanced oxidation processes (AOPs) for the elimination of VOCs in aqueous solutions [8; 14]. These methods are sufficient and effective treatment methods without producing high amounts of sludge as waste, because of the generation of hydroxyl radicals having a high oxidation power which is useful for the mineralization of the pollutants [8]. In the comparison of the use of membrane processes with the adsorption process or any other conventional methods for industrial water treatment, membrane processes have a significant advantage because the separation of mixtures can be achieved effectively at low energy consumption.