JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
Year:2001 | Volume:- | Issue:7-8|Papers Count:9

An increase in the production of dairy products, in the recent years in this country, has resulted in more concentrated and much higher volumes of emuents, causing environmental problems. Many producers are now experiencing extreme pollution loads on their current treatment facilities.A case study of a typical large dairy factory, situated in Isfahan province was carried out in this study. The factory, a major cheese producer, has already a conventional treatment plant, based on activated sludge technology.However the plant is highly overloaded; causing managerial problem on upgrading the current facilities.For this purpose, a pilot plant study was carried out to investigate the real capacity of this plant. It was concluded that to increase the treatment efficiency of the activated sludge process, receiving the pollution load of this factory, a three fold increase in the volume of the activated sludge tank would be necessary. Maximum efficiency of organic removal within the present system is 72 percent, which is not well below expectations. It is therefore recommended that the best option to further develop. This plant has to include a high rate in sedimentation tank and digestion will also be necessary.anaerobic system in the first stage prior to activate sludge tank. Improvements in sedimentation tank and digestion will also be necessary.

The tidal current is one of the major causes of the oil spill problems in Persian Gulf region. The astronomical tides have a dominant influence to the currents of Persian Gulf. The tide of the Indian Ocean affects the gulf via Hormuz strait as its main flow boundary. The results of harmonic analysis at Hormuz strait are used as boundary conditions of water level and then, the set depth averaged Shallow Water Equations coupled with a convection diffusion equation for the oil is chosen as a mathematical model in order to compute the propagation of tidal waves all over the gulf. The equations consist of Reynolds stress which simulates the variation of velocities due to turbulent effect. The scheme of Large Eddy Simulation is used for the computation of eddy viscosity coefficient. The equations are descritised using Galerkin Method on Triangular Unstructured Grids (Finite Element Meshes). The flow domain is divided into triangles using Deluaney Triangulation method. Such a model would help predict the oil spill tracking in Persian Gulf region.

Transport and probable distribution of the used cyanide in enriching and obtaining gold from the Muteh mines of Isfahan has been considered with regards to environmental geology and hydrology. The qualities of the area water resources, wastewater of the factory and solid tailings in tailing dam collected and examined from November 1996 to August 1997. This study showed that the alluviums in the Muteh plain in southern and northern parts are mainly coarsely granule texture and towards the stream of water flow, out of the plain the sediments are usually as fine granule. Geological constructions are mainly isotropic similar to hydraulic conductivity and physical characteristics in the western and north-western areas which indicate that flow velocity and distribution characteristics are constant. The elevation plan of ground waters show the direction of the flow of ground waters in the Muteh area from south and south-east towards west, north-west and north-east. The average concentrations of cyanide in reflux wastewater of the factory and in solid tailings were measured as 270mg/l and 6.4 mg/kg respectively. Water quality in the north-eastern, southern and south-eastern areas are in the category of sodic-chloride and towards the north-western, western and south-western areas change into calsicbicarbonate waters.The cyanide test was carried out over in the four seasons of the year. 47 samples of all existing water resources in the area showed a lack of cyanide to a measurable level in each season. Effective factors in distributing a chemical substance dissolved in water consisting of radial velocity of water, molecular diffusion and hydrodynamic dispersion coefficients and retardation factor of contaminant movement in aquifer were considered and maximum, minimum and average velocity of water were obtained 153.3, 1.4 and 46.2 meters per year respectively. With respect to the aquifer construction and extraction of coefficients of dynamic dispersion in both longitudinal and transversal directions from Anderson table and also with regard to the calculated velocity in this study, the maximum and minimum of hydrodynamic coefficients were calculated as 1.46 and 1.32x10-2 in longitudinal direction and as 292 and 2.64x10-3cm2/s in transversal direction respectively. The Pedet Number for maximum and minimum velocity was respectively calculated as 6.38x10-7 and 5.77x10-9 which emphasizes the effectiveness of molecular diffusion in the overall dispersion of cyanide because of being smaller than number one. The overall dispersion coefficient of cyanide was calculated in the aquifer of the muteh plain and 1.75cm2/s was achieved. Supposing that 0.5 percent of the aquifer construction consisted of organic materials and using the relation of groundwater and contaminant velocity ratio, retardation factor in the movement of cyanide was calculated and the maximum, minimum and average were respectively determined as 158.5, 1.12 and 70.2 which resulted in cyanide velocity that was 134.99, 0.0086 and 33.78 m/yr respectively.

A major branch in mathematical sciences, which has been given special attention recently, is optimization, including various methods such as linear programming, integer programming, and last not the least dynamic programming. Due to the unique characteristics of water and wastewater systems, specifically multi stage nature of such systems, dynamic programming has been widely applied. In dynamic programming a systematic procedure is used to determine a combination of consecutive decisions such that the overall system performance is maximized.The purpose of this research is the minimization of cost for industrial water treatment systems. To attain this goal in dynamic programming, it is necessary to determine the cost of each subsystem in various conditions. Next the dynamic programming procedure, determines the optimum system.In this paper, first the general case is considered, i.e., a cost function is defined for each treatment unit. Further, these are applied to the system under consideration, which may be any industrial plant whatsoever, and ~cost is evaluated for each and every subsystem. Finally the optimum system is obtained for the general function given below,Minimize z=[rn(Sn,dn)+rn-1(Sn-1,dn-1)+...+r1(S1,d1)]In determining the cost function of industrial water systems by reverse osmosis, ion exchange, and chemical precipitation, a number of factors should be considered. Among these foreign exchange rates, current domestic and international market prices, manufacturer's proposals, system components' life span, and bank deposit interest rates are of prime importance.

The electroplating industry has been playing a momentous role in the development of industries. Due to the rinsing water consumption rate, water conservation should ~e practiced by all the plating workshops. Reduction of water usage will result in waste minimization and savings in waste treatment. Case study carried out in Alaedin industry. On the basis of the flow measurement and characteristics of the waste, it is observed that the flow is 100 m3/day and the chromium and cyanide 37.2 and 24.11 mg/l respectively. From the in-plant evaluation it is concluded that the volume of drag-out and rinse water are mainly responsible for this waste generation.The optimization of the existing process with good housekeeping practices and the modification of process with improved rinse tank design as an application of clean technology are found satisfactory.Reduction in the speed of removal of work pieces from a plating bath to rinse tank reduced drag-out generation from 8m1/cm2 to 5m1/cm2 hence the volume of drag-out was reduced 37.5 per cent.By improving the rinse tank design and replacing with existing one. It is found that, this optimization and modification of rinsing tank in electroplating industry could reduce 41 per cent of waste volume and 83 per cent of cyanide and 81 per cent of chromium hence 82 per cent of chemical needed for reduction of cyanide and chromium.Reduction in sluge treatment and transportation cost also are the benefit of application of improved rinse tank.

In this study, in formation on solid waste management in Iran related to 119 cities in L984 and 273 cities in 1994 were collected. According to the results and findings, daily per capita generation of solid waste in summer has been more than winter (P<0.01).The average daily per capita generation of solid saste in 1994 was approximately 645 to 711 grams which is significantly more than the average generation in 1984 (P<0.0001). It was also observed that, while in 1984 the temporary storage method of solid waste were mainly "street dumping", in 1994 it changed to "solid wastes in bages and located at street kerbs" or near the doors of the buildings. In this decade, the number of, houses per municipal sweeper had increased from 150 per sweeper to 229 houses per sweeper. Moreover the trend of solid waste collection system in the cities under study has changed to daily collection program. Findings of this study showed that in 1984 handy cart was the main method of collection system, which was changed gradually to truck collection system.In 1994 in %28.2 of these cities there were no program for solid waste separation.During this period, solid waste collection costs had increased from 10.5 Rials per Kilogram in 1984 to 15.7 Rials per Kilogram, in 1994, which was significant from statistical point of view (P<0.0001).

Islamic Azad University, through the perception of its scientific mission and requirement of the country to the more specialists and skillful forces, took action to establish Science and Research Center of postgraduate studies at north-west of Tehran, in 1994. The establishment of such a high complex with this area and wideness certainly has had some positive and negative environmental results. So, the establishment of an environmental management system at this organization, due to identifying, controlling and decreasing the negative environmental impact of this project is required. Therefore, the intended research has been performed according to the necessity of Standard-ISO 14001, with respect of the establishment of environment management system and with the aim of study, investigation and assessment of the environmental impacts and aspects of the intended organization as well as considering the environmental management system of this university regarding its special ecological situation.Finally, the result of this research and study which determine the environmental situation of Science and Research Branch through composing the assessment studies of environmental impacts and systematical aim of standard of ISO 14001 (EMS), the necessity of establishing an environmental management system is required in this university center.

To environmental study and considering the value of seyyed Mahalleh and Zarrinkola lapou Abbandans, after preparing the base plan with the scale of 1:50000, sampling of plants (surrounding and aquatic) and animal species in four seasons was begun.The samples gathered, were Known in situ or in the laboratory, of the Department of Conservation of Environment of Mazandaran.The seyyed Mahalleh and Zarrinkola Abbandans entering and exiting waterways were sampled in fall and winter. Some biological and chemical factors were measured. The results of chemical and microbiological examinations are summarized in table 12.The social - economical values of these Abbandans were studied. The obtainable economical resources of these Abbandans are catching breed fish, harvesting rice and hunting migrant waterfowl birds.The income whjch gains from fish, rice and hirds was calculated. The known plants species included 6 kinds of surrounding plants, 22 kinds of aquatic plants in Seyyed Mahalleh Abbandan and 11 kinds of aquatic plants in Zarrinkola lapou Abbandan. Known hirds in Seyyed Mahalleh and Zarrinkola lapou are 20 and 16 kinds. Known amphibia and reptiles are 3 and 8 kinds. These are a few kinds of plants and animals species, hut there are a lot of waterfowl species in these. Abbandans.

Concerning the newness of economical valuation methods of the country parks and forests, in this research it is attempted to validate sisangan forest park using one of the classical and common methods. On this basis, some semicircle was drawn with the park as the center and with equal radiuses.The Country was divided into six different zones. Then, calculating the surface of each region and its resident population, also the money required by people to visit the parks was calculated. According to the collected data from questionnaires, and the estimations.The regressional equation between the mentioned parameters was attempted. Through the data analysis, the forest park demand curve, was drawn which was indicator of high recreational value of the sisangan park (52.932 million Rials).The results indicate that by using right and proper management the conservation of the natural environment and environmental values, as well as the recreational requirements of the people provide.