مجله آب و فاضلاب
پیاپی 116 (مهر و آبان 1397)

As Iran moves forward with the development of a sustainable integrated water management plan, water reuse, including the potable reuse, can play an important role in the overall success and implementation of the plan. As part of this effort, the Iranian journal of water and wastewater requested papers on the subject of water reuse. In response to that request, this paper, to be published in three parts, deals specifically with the subject of water reuse and the potential application of potable reuse in Iran. The principal focus of this paper (Part I) is on the background information that is necessary to understand and assess the potential application of potable reuse in Iran. Topics addressed in this paper include: 1) consideration for why potable water reuse in Iran, 2) background information on potable water reuse, 3) a comparative assessment of potable water reuse with alternative sources of water supplies. The information presented in this paper is needed to understand the issues and challenges presented in the subsequent papers. Technical and regulatory issues related to potable reuse are considered in Part II. The path forward and implementation challenges, including public outreach, are addressed in Part III.

This paper (Part II) is the second in a series of three papers on water reuse and the potential application of potable water reuse in Iran. Introductory and background material on potable reuse was presented in Part I. The principal focus of this paper (Part II) is on the technical and regulatory issues that must be considered in implementing a potable water reuse program. Topics addressed in this paper include: 1) public health considerations in potable reuse, 2) representative advanced treatment trains used in potable reuse, 3) the importance of source control, 4) upgrade to secondary wastewater treatment plant for potable reuse, and 5) environmental buffer for potable reuse. The path forward and implementation challenges, including public outreach, are addressed in Part III.

This paper (Part III) is the third in a series of three papers on potential application of water reuse for potable use. Introductory and background material on potable water reuse was presented in Part I. Technical and regulatory issues related to potable water reuse were presented in Part II. The principal focus of this paper (Part III) is on the issues that must be evaluated, beyond the technical and regulatory issues discussed in Part II, when considering potable water reuse. Topics addressed in this paper include: 1) the path forward for potable water reuse in Iran; 2) implementation challenges, including those associated with public outreach for potable reuse application in Iran; and 3) closing thoughts on the future of potable reuse in Iran. In the path forward, the case is made for employing a decentralized wastewater management strategy utilizing satellite wastewater reclamation facilities for water reuse, including potable reuse. The lack of operating experience with advanced water treatment facilities and potable reuse regulations are among the many challenges that must be overcome in the implementation of potable water reuse in Iran. To meet future water needs a sustainable water resources management program that includes potable reuse, as part of the water portfolio, must be developed for Iran.

Aromatic compounds such as total phenolic (TP) compounds commonly present in effluents of food and agricultural industries such as Olive mill wastewater (OMW). The high concentration of TP in OMW is usually associated with high measurement of chemical oxygen demand (COD). Discharge of these chemicals to water ways can creat hazardous environmental condition and have adverse impact of the living organisms. Biological treatment is the most effective method for removing or partially decreasing these chemicals from wastewater. In this study, the biodegradation of OMW was investigated by using an airlift bioreactor with Ralstonia eutropha equipped with net draft tube (ALR-NDT). The effect of aeration rate and initial TP concentration on the efficiency of the biodegradation process was studied. Innitially, the effect of three aeration rates (100, 200, and 400 mL/min) on TP reduction was studied. The aeration rate of 200 mL/min was found to be as the optimal aeration rate for the biodegradation process. Following these initial experiments, the effect of the three initial OMW concentrations (660, 1220, and 2620 mg/L) were evaluated on TP reduction in the follow up experiments. Results of our study showed that the TP reduction under the above three initial OMW concentrations were 95%, 96%, and 58%, respectively. The maximum TP reduction (96%) were accomplished when the initial TP concentration was1220 mg/L. For future kinetic modeling investigation, we were able to use the experimental data and confimed the behavior of the process as a Monod kinetic model with kinetic coefficients of µmax= 0.22 1/hr and Ks= 863 mg/L. According to the our preliminary results, Ralstonia eutropha was found to be capable of degrading high concentration of phenolic compounds from industrial wastewater.

Some of the nanoparticles such as zinc oxide have a significant antibacterial activity that can be used in removal of pathogenic organisms in certain water resources application. This study was specifically undertaken to investigate the use of cement matrix modified with Zinc oxide nanoparticles to prevent the growth of Pseudomonas aeruginosa and Bacillus cereus. The results showed that ZnO nanoparticles with the size lower than 20 nm were dispersed well in the cement matrix. Results also showed that inhibitory effect against gram-negative bacterium of Pseudomonas aeruginosa was higher than gram-positive bacterium of Bacillus cereus. Also, confinement of ZnO nanoparticles by cement materials reduced the photocatalytic activity slightly. Based on the preparation of antibacterial formulation of cement matrix containing ZnO nanoparticles, concrete surfaces with ZnO nanoparticles can be used in a wide range of aquatic environments for prevention of pathogenic bacterial growth.

Microbial fuel cell (MFC) is a biochemical treatment system in which the wastewater is treated by biodegradation of organic maters in peresence of bacteria while the electricity can be produced simultanously. The purpose of this study was to investigate the use of a dual-chamber microbial fuel cell (MFC) for the removal of biodegradable waste in wastewater through COD measurement.At the same time, the amount of electricity produced was measured during the experimental evaluation. MFC was equipped with the nafion as a proton exchange membrane from the anode to the cathode and with the graphite as electrodes. Also, glucose, molasses, date syrup, meat wastewater (Sausages) were used as carbon source. The experiments were performed by applying the Saccharomyces cerevisiae as biocatalysts at room temperature and neutral pH. The performance of MFC was studied under different carbon sources with different nafion membranes (117, 112, 212) and two different inoculum biocatalyst conditions (2 and 5 volumetric percent). The ability of COD removal using S. cerevisiae and electricity generation were examined with different substrates. The results obtained from this study showed that the microbial fuel treatment system is an effective method to remove organic materes from wastewater. Maximum COD removal of about 91 percent were obtained in MFC when glucose Nafion membrane and inoculum catalyst were 117, and 5 volumetric percent, respectively. The electricity power density generated under this condition was about 78 mW/m2.

The high volume of wastewater generated in the textile industry and the related die may sometimes be discharge into the environment. Azo dyes are an important class of dye compounds that are being widely used in textile industry. Several physical and chemical techniques are usually used for the removal of dyes from wastewater and a few of them have been accepted in the textile industries. Specific aim of this study was to investigate the potential use of aqueous two-phase systems in removal of the azo Congo Red dye from the textile wastewater effluent. In this study, the various aqueous two-phase systems containing polyethylene glycol (PEG) with 1000, 4000 and 8000 g/mole of different types of salts including Sodium Sulfate, Sodium Sulfite and Sodium Carbonate. The results of this study showed that the polyethylene glycol with 1000 g/mole including sodium sulfite was most suitable for the removal of the Congo Red dye from textile wastewater with the efficiency of about 98.8 percent. This result was obtained under operating condition consisting of: 25 w/w percent polyethylene glycol 1000 with 10.7 w/w percent sodium sulfite. From the results of this study we can conclude that the ATPS is an effective method for successfull removal of Congo red dye from textile industry.

Waste load allocation (WLA) is one of the most important elements when evaluating in water quality management problems. Due to multiple and sometimes conflict objectives in WLA problems, a set of Pareto optimal solutions is derived with evolutionary algorithms in which one of these Pareto fronts could be influenced by conflicts. In this research study, simulation-optimization approach was applied by QUAL2Kw simulation model and particle swarm optimization (PSO) as optimization algorithm to assign cBOD point source pollutions for specific location along Gheshlagh River. To reduce the conflicts between beneficiaries for the optimum operation of water resources in river, the level leader-follower and the Nash bargaining game theory models were applied. The results showed that the construction, maintenance and operation costs of the treatment plants for leader-follower and Nash bargaining game theories were about 192 and 293 billion Rial, respectively. The penalties for violating the environmental regulations set by the Iranian environmental protection agency (EPA) for the above theory models were found to be about 32 and 3.9 billion Rial, respectively. Furthermore, the estimated penalty tariff for each overdischarge of allowed cBOD under Stackelberg and Nash bargaining game theories were about 10.8 and 3 Rial, per environmental violation, respectively. The estimated penalty tariff in Stackelberg game is extremely close to current Iran’s EPA penalty tariff.

In this research, Fault Tree Analysis (FTA) with fuzzy and crisp approaches were used to assess the risk associated with the performance of water treatment plants. The fuzzy logic was used to consider the uncertainties in expert opinions and the nature of threats. This modelling approach was implemented as a case study in Jalaliyeh water treatment plant in Tehran. One undesirable event in such structure was improper water quantity and quality. The results of this case study showed that probability of treatment plant failure under fuzzy and non-fuzzy methods are 19% and 10%, respectively. The risk treatment plant failure was found to be within the low to medium range. For risk assessment, multiple components were found to influence the failure of treatment plants. Our evalutation showed that the following items were ranked as highest to lowest to influence the treatment plant failure: inappropriate tank design, power equipment failure, failure of transmission line, and inadequate repair and maintenance of the pumps.

Treatment capability of a constructed wetland is heavily dependent on the uniformity of flow moving inside the wetland. This modeling study was performed to evaluate the effect of flow distribution on internal hydraulic behavior of horizontal subsurface flow constructed wetland. To accomplish this objective of the study, three different inlet flow configurations including (1) midpoint, (2) corner and (3) uniform while keeping a fixed midpoint outlet flow for all configurations. The model used in this study was based on COMSOL Multiphysics platform for subsurface flow differential equation in porous mediums (Darcy law). Hydraulic head zoning indicated uniform flow distribution in form of parallel streamlines from inlet to outlet in configuration 3 while substantial number of shortcuts and a noticiable difference between high and low pressure areas were observed in configuration 1 and 2. Results obtained from the simulated streamlines and pressure contours throughout the wetland confirmed the field observation results. Hydraulic head range at each configuration is 14.35, 15.25 and 13.05 cm, respectively. Results indicated an appropriate hydraulic performance of the uniform inflow configuration to use the whole capacity of constructed wetland for treatment process. Meanwhile, midpoint inlet configuration had a proper performance by considering some criteria to reduce dead volume and shortcuts.