Alireza Rahmani, Zeynab Masoumi, Zeynab Atashban, Ghasem Azarian,
Volume 14, Issue 4 (9-2016)
Abstract
Introduction: It is obvious that, the organic load of wastewaters produced by food industries, especially the egg processing industry, is very high, therefore, it is necessary to use a cost efficient method with high efficiency for the treatment of this kinds of wastewater. Thus, the aim of this study was to investigate the effect of the electro-coagulation process for the treatment of the wastewater of egg processing industries.
Methods: This experimental study was carried out on the wastewater of this industry in a batch system during three seasons (summer, autumn and winter) in 2015. Without pH adjustment, the effect of operating parameters including current density, retention time and electrode type, on COD reduction was investigated. Also, the technical and economic assessment in terms of energy and electrode consumption was studied.
Results: The results showed that, COD removal efficiency increased with increasing current density as well as increasing operating time; naturally, it is necessary to determine the optimum points in order to reduce operating costs including energy and electrode consumption. Maximum removal efficiency of COD (99%) was obtained using the aluminum electrode at contact time 10 min and current density of 7mA/cm2. Also, aluminum electrode with energy consumption of 9kwh/m3 and anode consumption of 0.5 mg/cm is more economical than iron electrode.
Conclusion: According to the results, in comparison to conventional methods, the treatment of the wastewater of egg processing industries using the electro-coagulation process is more effective and cost efficient.
Tayebeh Hatami, Azam Nadali, Ghodratollah Roshanaei , Reza Shokoohi,
Volume 16, Issue 3 (4-2018)
Abstract
Background and Objective: Due to increasing the water demand and the lack of its resources, the reuse of effluents is considered as a useful option in the water resources management. The aim of this study was to evaluate the possibility of the reuse of effluents from the extended aeration process in the wastewater treatment plant of the Bojnoord city for agricultural uses.
Materials and Methods: This is a descriptive-analytical study which performed in 2013 on the quality of effluents in the wastewater treatment plant of the Bojnoord city by measuring the parameters of Electrical Conductivity (EC), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), nitrogen, phosphorus, Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Sodium Adsorption Ratio (SAR), sodium percentage, magnesium ions, potassium ions, calcium ions, sodium ions and chloride.
Results: The results shown that, the removal efficacy of BOD and COD were 88% and 89%, respectively, and it was higher than 85 percent for TSS and VSS factors; thus, the average residual concentration of BOD, COD, TSS and phosphate in the outflow were 27, 61, 26 and 11.34 mg, respectively. The average values of pH and EC in treated effluent were obtained 7.45 and 1940 μs/cm, respectively. Moreover, the values of chloride and SAR for the effluent of the wastewater treatment plant of the Bojnoord were achieved 3.89 meq/L and 221 mg/L, respectively.
Conclusion: based on the results, it can be concluded that the effluents of the wastewater treatment plant of the Bojnoord city can be valuable for use in agriculture; but, due to the high concentration of chloride in treated effluent, it is recommended that this effluent used for semi-sensitive plants. Furthermore, this effluent is not suitable for feeding to groundwater and for discharging into the surface water and it is needed to advanced treatment based on the standards.
