Assessment of persulfate (ps)/uv-c process for drinking water treatment

Abstract

In recent years, there has been a significant amount of effort placed on the development of advanced oxidation processes that are based on sulfate radicals. SO4 •− offers several advantages over OH•, including a high redox potential (2.5 - 3.1 V), which is significantly higher than the redox potential of OH• (1.8 -2.7 V), excellent selectivity, and a long half-life (30 to 40 μs). In addition, SO4 •− is capable of successfully reacting with the contaminants of interest across a broad pH range (ranging from 2 to 8). SO4 •− can break down refractory organic contaminants in water, turning them into carbon dioxide, water, inorganic salt, and other molecules with a smaller molecular compounds. Peroxymonosulfate (PMS) and persulfate (PS) can be converted into these radicals via catalytic, radiation, or thermal activation, among other mechanisms. The most significant component that determines water quality is the amount of organic matter that is present in the water. Scientists have spent a significant amount of time and effort looking into the effects that organic matter has on conventional drinking water treatment plants over the many years that have passed. The presence of organic matter in water can lead to a variety of unwanted effects, including changes in the color, taste, and odor of drinking water plants; negative variation in the water's overall microbiological quality; the requirement for the installation of additional treatment units; and so on. As a result of this, the removal of organic matter is becoming an increasingly crucial practice with each passing day. This research focuses primarily on the enhancement of UV-C tertiary treatment using sulfate radical based photochemical Advanced Oxidation Processes (SR-AOPs). This is done in order to treat effectively (mineralize) the organic carbon that is naturally present in raw water, the coagulation-flocculation effluent, the filter effluent and the final effluent. Within the first section of the thesis, experimental research was carried out to investigate the ways in which the initial oxidant concentration influences the effectiveness of the process. Total organic carbon (TOC) removal efficiency, residual oxidant concentration, and UV254 modification were among the data used to establish the procedures' guiding principles. Through the utilization of the PS/UV-C process, a comparison was made on the practicability of using PS oxidant for TOC removal. In terms of determining the effect of initial concentration of oxidant on the mineralization processes, research was conducted using samples that came from a drinking water treatment plant. Each sample had an initial TOC value, and initial value, and the initial PS concentration ranged from 0.1-1.0 mM. The research was conducted in order to determine the effect that initial concentration of oxidant had on the mineralization processes. During the reaction, evaluations of TOC, PS, pH, and UV254 are carried out on samples that have been taken at predefined time intervals (the initial, the 15th minute, the 30th minute, and the 60th minute). As a result of this research, according to the total organic carbon (TOC) removal evaluations, the persulfate/UV-C process is most efficient when used in the raw water coming to the drinking water treatment plant. In conclusion, it was determined that sulphate radical-based photochemical advanced oxidation techniques, when applied to natural or treated waters under the suitable reaction circumstances, are capable of efficiently removing organic carbon.