ABSTRACT
Usage electrocoagulation methods for removal chemical contaminants are widely used in the recent years. The aim of this research is to investigate fluoride removal, agent dental and skeletal fluorosis, from drinking water by batch electrocoagulation reactor with using aluminum electrode. In this study, the drinking water sample is prepared by plastic batch reactor by monopole electrode. Removal efficiency is studied in different conditions, included pH [4, 7, and 10], reaction time [5, 10, 15, 30, and 45 min], distance between electrode [2 cm], and current density [1.5, 3, and 4.5 mA/cm[2]]. In electrocoagulation reactor, percentage of removal fluoride 2 mg/L, current density 4.5 mA/cm[2] and reaction time 30 min in pH 4, 7 and 10 are obtained 96.5%, 100% and 90.5%, respectively. In electrocoagulation reactor, percentage of removal fluoride 12 mg/L removal in distance 2 cm, current density 4.5 mA/cm[2], and reaction time 30 min in pH 4, 7, and l0 are obtained 60.7%, 64%, and 56% respectively. The findings indicated that fluoride removal efficiency is increased with increasing current density and reaction time. The results indicate that increasing the concentration of fluoride ions, the time required to achieve good efficiency should also increase. It can be concluded that the electrocoagulation technology is an effective process for defluoridation of drinking waters.
ABSTRACT
This study aims to describe the application of water pinch technology in industrial water consumption management in aluminum anodizing industry. Water pinch analysis is a systematic technique for designing, optimization and retrofitting of energy, mass and water recovery networks. The selection of different operations existing in an industry has an important role in correctness of application of pinch technology. Water usages in anodizing industry are various, but researches have been shown that, it has the best efficiency on the selection of rinsing chambers to pinch technology. There are different methods in pinch technology mostly based on mass transfer of single or multiple contaminants. In this research, a new method is used to select effective contaminant to be applied to pinch analysis. This research is based on Mann and Liu's method in single contaminant. But "the guide for classification of raw water, wastewater and recycled water for industrial and recreation" is chosen to use a complex of index contaminants as a single contaminant. This method is very simple and applicable for various industrial processes. By an index contaminant like total dissolved solids, the water usage reduced about 6.7%. Using pinch technology and this new approach in three rinsing chambers, water usage reduced about 14.4%