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Background & Aims of the Study: Detergent and phosphate are one of the main and vital threats (eutrophication phenomenon and production of synthetic foam) for the source of drinking water, agriculture and industrial uses in the Ahvaz, Iran that threaten human health. The aim of this study is the evaluation of the efficiency of the electrocoagulation (EC) process in the removal of detergent and phosphate from car wash effluent. Materials & Methods:In this experimental study, we used a glass tank with a volume of 2-4 liters (effective volume of 2 liters) containing 4 electrode-plate iron and aluminum (AL-AL, AL-Fe, Fe-Fe). Bipolar method was used to convert alternative electricity to direct; electrodes were connected to a power supply. Daily samples were collected from different car washes sewage. Initial PHs of samples was from 7 to 9. At first, different tests were performed on primary samples. Reaction times were set for 90, 60 and 30 minutes with middle intervals of 2 cm. Results: According to the result of this study, percentage of phosphate removal in the EC with Al-Fe electrode, with an optimum pH = 7, has been from 34 % (in the 10 Volt) to 78% (in the 30 Volt). Percentage of detergent removal in the EC with AL electrode, with an optimum pH = 7, has been from 68 % (in the 10 Volt) to 94% (in the 30 Volt). Conclusions: Altogether, it was found that this method can be used as a confident and convenient method for treating car wash effluent and according to the highest removal efficiency of the process, effluent can be discharged safely into the environment.

Background: High concentrations of natural organic matter (NOM) may cause the production of harmful compounds in treated drinking water. Surfactant-modified zeolites (SMZs) with various loadings of sodium dodecyl sulfate (SDS) have been used as adsorbents to remove NOM from aqueous solution. SMZ has presented higher NOM adsorption more efficiency than natural zeolite. NOM affects the quality of drinking water in several points. Objectives: The purpose this study was to investigate the SDS-modified isotherm of natural Iranian zeolite obtained from Semnan mines, for the removal of NOM from aqueous solution. Materials and Methods: The adsorption of NOM onto SDS-modified zeolite as a function of contact time, initial NOM concentrations, adsorbent dose and solution pH was investigated. The isotherm experiments were carried out with fixing the adsorbent dose and varying the initial concentration of NOM. Results: The results indicated that SDS-modified zeolite showed greatly enhanced adsorption capacity. Findings revealed that the Langmuir isotherm best described the NOM adsorption on the adsorbent. The adsorption isotherm was well fitted to the Langmuir model. The maximum adsorption capacity of SMZ with surfactant bilayer coverage for NOM was 111 mg/g at 25°C and pH = 5. Conclusions: The findings of this study showed that the modification of natural zeolites can achieve higher adsorption capacity for organics. In addition, based on the results, natural zeolite being modified with SDS as a cationic surfactant had good efficiency for the adsorption of NOM.

Object Arsenic as a chemical is found in rock, soil, air and used in various industries and their products, such as colors, hairs, and fertilizers. Humans may be exposed to arsenic mainly through food and drinking water. Due to its adverse health effects, its presence in drinking water has become a public health concern. Methods In this systematic review, we investigated the relationship between arsenic concentration in drinking water and the risk of kidney cancer in humans. For this reason, various electronic databases were searched from 1992 February to November 2021. In this review, three ecological studies, two case-control studies, and four cohort studies were investigated. Results High levels of arsenic (100 μg/L) have been reported in many countries such as southwest Taiwan, Niigata, Argentine, and northern Chile. A significant relationship was observed between kidney cancer incidence and its mortality rate with high arsenic levels in drinking water. Conclusions Despite the limitations in some previous studies, reviewing and comparing the data of different regions indicates a scientific relationship between kidney cancer incidence and high concentrations of arsenic in drinking water.