Issue 3

Wastewater generated in oil production and refinery industries contains high levels of pollutions. Water from the oil production field is the largest source of wastewater in the oil production and refinery industry. It can cause environmental problems on a global scale due to its high volume and pollutant properties. The treatment of produced water and refinery wastewater is traditionally carried out by physical, chemical, and biological treatment processes. In recent years, it has been focused on the use of membrane technologies. In the treatment of oil production wastewater, membrane bioreactors are used as pre-treatment and / or direct treatment methods. In this study, the treatability of wastewater generated in the oil production field by membrane bioreactor was investigated. The system has been operated for 70 days and its efficiency has been evaluated. Treatment parameters such as chemical oxygen demand, total solids, total nitrogen, total phosphorus, Alkalinity, and conductivity were analyzed. In addition, flux and transmembrane pressures were measured. Result, chemical oxygen demand, total solids, total volatile solids, suspended solids, total phosphorus, total nitrogen and sulfate, average removal efficiencies 65%, 65%, 58%, 73%, 70%, 50%, and 57% was obtained, respectively. It has been determined that the system used can be used in petroleum production wastewater treatment.

The large cities are facing with a phenomenon called high-rise buildings which is due to the increasing of the population and also developing the cities. One of the negative impacts of high-rise buildings is the change in urban wind flow. Air pollutions is a major problem in the cities and the wind play an important role in the dispersion of air pollutions. The most probable wind direction for Tehran is west and hence district twenty-two of Tehran municipality which is located in northwest of Tehran (Capital of Iran) is in the dominant direction of wind flow. This paper presents a numerical method to investigate the interaction between the wind flow, pollution and high-rise buildings in district twenty-two of Tehran municipality. The effect of these phenomenon on the other regions is considered as well. Computational fluid dynamics (CFD) by ANSYS Fluent software has been used in order to simulate the problem. The results of this study indicate the existing buildings and their layout had no effect on wind velocity and trapping the pollution and do not cause an increasing of the local concentration of pollutants. So the geometry and layout of buildings allow the flows and environmental pollutants to pass.

The Heihe River is the second longest inland river in China, which is one of the most important inland river basins in the northwest area. The effect of drought on ecological environment can be exacerbated by climate change. Eco-water diversion project was implemented since 2000 to solve the increasingly serious problem of ecological environment deterioration in the lower reaches of Heihe River Basin. In order to reveal whether the eco-water diversion project solve the ecological environment deterioration thoroughly, the change of hydrology and vegetation were investigated and compared by using the remote sensing data, field surveys, monitoring and statistics data. Our results showed that the soil water content, groundwater level and vegetation coverage increased after eco-water diversion, especially in 0-20cm, the value increased 30.05%, which results vegetation restoration in some area. However, the seasonal distribution of eco-water diversion is extremely uneven, 70% of the runoff is mainly concentrated in January to March, and September to October. Water was seriously insufficient in the critical water demand period of plants such as germination and fruit period due to river cutout. Moreover, some areas were degraded due to salinization. In addition, the extreme change of soil water is not conducive to plant growth, but will increase the waste of water resources due to the increasing of ineffective surface evaporation. It is difficult to improve the quantity of discharged water in the upper reaches of Heihe River, so the distribution time and mode is very important for stable and healthy development of vegetation in the downstream. Therefore, eco-water diversion project is not a simply measure to improve the ecological environment. We suggested that hydrological processes should be consistent with ecological processes in the lower reaches of Heihe River, otherwise, the most important significance of eco-water diversion project will be lost. Exploring this will be helpful in formulate scientific and reasonable water dispatching scheme, achieve water resources allocation and water demand matching, improve ecological benefits.

Drinking water supply is a preeminent to public health, environmental protection, quality of life, economic activity, and sustainable development. Many disasters are being recorded due to poor water quality every day. In this case, it is essential to assure safe water demand through continuous enhancement and improvement of all practices and processes related to the water supply. The Water Safety Plan (WSP) concept has become a globally recognized and accepted approach to drinking water supply management and operation. This study aims at reviewing the WSP risk management approach around the world. In addition, the four success factors of WSP implementation are discussed. The benefits, difficulties, as well as recommendation from recent studies that implemented WSP is presented. Improving water quality and operational efficiency were the main benefits whereas lack of staff training and insufficient time and fund were the main challenges for effective WSP implementation. According to a literature scan, the water utilities in Arab gulf region countries do not implement WSP, thus, the author encourages water utilities in these countries to conduct WSP to improve water quality management.