JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2004 | Volume:- | Issue:21|Papers Count:9

Industrial development and technological progresses, however improve the human life standards and give him the efficient tools to face disasters but it create a new types of potential hazardous situations such as chemical accidents. A chemical accident is defined as sudden and uncontrolled release and dispersion of reasonable amount of a hazardous chemical which affect a vast area of environment or human society. The control and mitigation of environmental impacts of chemical accidents need basic study and knowing the potentials of chemical accidents as well as starting to control the dangerous situations and reducing their risks by improving the chemical facilities safety level. Establishment of a special committee as a central authority to cover all chemical affairs and promote the safety level of using, storage , transportation and distribution of hazardous chemical to reduce the chemical accidents is recommended. This committee must use the new techniques of hazards identification and risk assessment . Use of computerized programs comprise of data bank, GIS and dispersion models which are capable of communication each other, are growing as a preparedness and response tool to prevent and mitigate the disaster effects. A city hazardous gas monitoring network to detect the leak of toxic and combustible gases in the primary stages is another tool to reduce the risk of chemical accident. Direct viewing of high risk areas by TV camera and mounting the SOS telephone sets are the other useful methods to prevent the chemical accidents and to improve a city chemical safety.

Algae are a group of living things with very effective role in absorption and separation of heavy metals and are particularly economical in refining dilute wastewaters. Where as, application of live algae is very difficult in the industry, therefore their dead forms or material attracted from them are used. This study was made on sargassum algae (which is a macro algae from brown algae which is found in abundant amount in Persian Gulf) in continues system. In this article capacity of sargassum in heavy metals (Cr3, Cu2, and Ni2) absorption has been studied. The evidences have showed that continues system of low flow rate can reduce the heavy metals concentration to levels as low as required by environmental legislation but in concentrate wastewater and high flow rate the remained heavy metals is high. The capacity of each gram of sargassum on this heavy metals absorption is about 5.15 mili mole and dried sargassum usage for heavy metals removing is more economical than lime usage or ion-exchange methods.

The main purpose of this study is to investigate and financially justify the implementation of municipal, agricultural and industrial wastewater treatment in khouzestan Province Cost-Benefit method has been used for this Feasibility Study The required data and information have been gathered from various sources, such as Statistic Center of Iran, Department of Environment, a study on wastewater treatment in Khouzestan Province, World Bank, United Nation Development Program (UNDP) , Ministry of Health and Fishery Office. On his basis, the impacts of pollution and damages concerning existing situation of wastewater management have been reviewed and evaluated financially. Considering the cost of existing situation damages as benefit of implementation of wastewater treatment management, the benefit of this implementation is about 8.18 *1012 Rials. The interest devaluation method has been used for calculation of the value of this benefit for 10 years as design period, and net present value (NPV) was calculated as 30.12*1012Rials. However the cost of implementation of wastewater treatment management is about 9*1012 Rials. Considering the related issues for wastewater management, the net profit rate is 235%. Accordingly, implementation of municipal, agricultural and industrial wastewater treatment in Khozestan Province is highly recommended and has remarkably financial justification, because profit rate of this project is a bout ten times higher than the interest rate.

Malachite green is a carcinogen and mutagen material that is prohibited by FDA as a fungicide for edible fishes. Alvita (sodium di acetate), is a fungicide and bactericide material which is admitted by FDA. This research has been carried out in vivo in Niyak farm, there were 5 traphs for trout culture, that one of them was blank, three of them contained Alvita, with 1 g/lit for 30 minutes, 1g/lit for 1 hour, 2 g/lit for 30 minutes and one of them contained malachite green with 2 mg/lit concentration for one hour.All of examinations were done in triplicate. The results with 95% confidence, concentration of (1 g/lit) Alvita, was the best alternative of malachite green(P=0.265).

In this research, the economic and technical method of power plant wastewater treatment and removal of heavy metal (specially in Sahand wastewater) has been studied. The result indicate quality and quantity of that wastewater in power plant depend on the type of fuel, combustion units capacity, their operation and material used in this structure. Common point in wastewater is that any of them is not permanent and all of them are periodic. In this research ,PH changes and flocculation and coagulation are being used to study the removing of heavy metals. Therefore, with similar artificial wastewater characteristics for preheating air and chemical washing boiler wastewater of Sahand power plant wastewater prepared. It should be mentioned that there are heavy metals only, in preheating air and chemical acidic washing boiler wastewater. Hence removal percent of heavy metal in mentioned wastewater and in the other wastewaters is studied to define the acidity neutralization. In poisoned air preheating wastewater and acidic washing boiler wastewater treatment, following the method of precipitation of heavy metals in basic PH, at first pH of two wastewaters is raised to 8,9,10 with addition of caustic soda. In this step removal percentage of heavy metals measured in atomic absorption method, illustrates in air preheating wastewater with PH =9 and in acidic washing boiler wastewater with PH =8 the most removal percentage of heavy metals obtained. In air preheating wastewater and with PH =9, removal percentage of Fe, V, Ni, Cu respectively is equal to 99.88%, 93.54%, 99.77%, 95.73% and in acidic washing boiler wastewater with PH =8 the removal quantity of Fe obtained 99.65%. Hence, in order to obtain more removal percentage of heavy metals and reaching to Iran environment standard, treatment was continued with flocculation and coagulation method by using Ferric chloride, Ferric sulfate and Alum in 4 concentrations 25, 50, 75, 100. In air preheating wastewater, after atomic absorption test on these samples and evaluation of results, it was obvious that the most removal percentage was obtained by adding of alum with concentration of 25 mg/lit. In this condition the removal percentage of Fe, V, Ni, Cu respectively is equal to 99.98%, 99.99%, 99.97%, and 99.89%. In acidic washing boiler wastewater the most removal percentage was obtained by adding Alum with concentration of 50 mg/lit. In this condition the removal percentage of Fe was equal to 99.98 Acidic amount in basic wastewater treatment was measured and for neutralization step, sulfuric acid was added to wastewater. In preparation boiler surface wastewater, aeration method was being used in order to removal Ammonia. Ammonia quantity in Wastewater can be recognized from its order. But after aeration in 0.5 hour, the quantity is decreased and the odor is no more recognizable. After finishing aeration for neutralization step, sulfuric acid was added to wastewater.

Tehran as the capital and biggest city of Iran has so many attractions which have resulted in problems such as industries centralization and increasing population in and around the city. Therefore water demean has become ever increasing. It is important to notice that discharging untreated domestic and industrial wastewater of the city into the groundwater has resulted in much pollution and raising level. On the other hand, and in recent years there was decreasing rainfall and so water shortage has been obvious. Therefore, it seems an essential task to reuse and or recycle water in present industries. For this study and among the established industries in Tehran area, factories having fifty or more workers of textile, tannery, pulp and paper industries have been chosen, as the test society. Most of the tanneries were transferred from Tehran city to the outside and about 14.5% of total remained industries are related to textile, Pulp and paper manufacturing in the first phase of this study. The qualitative and quantitative characteristics of water used in these factories and possibilities for water recoiling have been investigated. The results of study showed that the most consumption is related to textile industry. Water needed for all chosen industries is brought about from tap water (11%), tap water and deep weels (11%) and deep weels (78%) chosen industries which water utilized in industry, supply from city water 11% city water and well 11% and only well 78%. The amount of wastewater produced by textile Wood pulp and paper and trainees water industries in Tehran area is about 21500m3 and considering 200 liters per capital wastewater production, it is equivalent to 107500 persons wastewater production. Among textile Wood Pulp and paper and tannery industries, the most wastewater production is related to textile industry with about 87% of total wastewater production.