Statistical modeling of future lake level under climatic conditions, case study of Urmia lake [Iran]

The present research focuses on the changes of Urmia Lake level. For this purpose, two time scales have been considered. The trend changes of temperature, precipitation rate and quantitative values of climate type for the observational period from 1968 to 2011 [past scale] and from 2011 to 2100 [future scale] have been analyzed. General Circulation Model [GCM] is considered for simulating the values of the future meteorological components, and statistical models have been used for modeling the lake's level in future decades. One of the most significant results achieved for the future decades is the increase of the lake's temperature for around 1.5 degrees centigrade till 2100 in comparison with the long-term average of 1961 to 1990. Furthermore, the values extracted from precipitation rate and climate type of the zone also indicate a remarkable decrease of quantitative values in the future decades. Accordingly, the climate type extracted for the year 2100 with numeric value of around 17.75 will be entered a new phase called arid climate for the first time in recent decades. The Lake surface area is diminished from 5650 square kilometers in 1998 to about 2005 square kilometers in 2010. According to the results achieved by statistical models and time series, if this trend continues, the Lake level will be reduced around 3 more meters in 2100

Water consumption management and its role on energy saving, case study of Tehran, Iran

Due to shortage of precipitation and the spatial and periodical disparity of rainfalls, Iran is counted among the arid and semi-arid countries of the world, and therefore the water utilities have put the control of consumption and efficient use of water high on their priorities. Water consumption management is considered as a field of energy management, and the impacts of effective measure related to water consumption pattern and its optimization on reducing demands are quite clear. Therefore one of the main objectives of consumption management policies is to optimize energy and reducing the costs of energy needed to supply potable water from production sources. To have a relative estimate of the amount of energy reduced as a consequence of consumption management the outcomes of a case study undertaken in a region of Tehran were used. In this study, the application of consumption management measures yielded in a 19% reduction in water consumption. This amount of reduction limits requirements from production sources such as wells and treatment plants and its direct impact is to reduce the required energy and the costs of water supply

Evaluating the effects of fertilizers on bioavailable metallic pollution of soils, case study of sistan farms, Iran

Present study determines not only the total amounts of metals [Cr, Cu and Pb] in superficial agricultural soil of Sistan area in Eastern Iran, but also the chemical partitioning of these elements in seven statistically selected cases. The analysis was run for local soil, soil treated by non-contaminated organic, compost and chemical fertilizers as well as soil treated by metal-contaminated fertilizers. The sampling campaign was done in Zabol University research farm in 2009. The grab samples were taken from seven different cases, the chemical partitioning analysis was performed and metallic concentrations were detected using FAAS. It may be concluded that the bioaccessibility of metals Cu and Cr would be increased in case of imposed contamination where the soil is treated with all three kinds of fertilizers. Although a relatively similar distribution pattern is seen between anthropogenic and geopogenic portions of bulk concentration in all three kinds of fertilizers, chemical fertilizer seems to manifest a more risky condition. According to the results achieved by cluster analysis, a close correlation exists between Cu and Cr behavior which may be attributed to the geological texture of the study area. In accordance with the results gained by partitioning analysis, IpOLL index values also show contaminated chemical fertilizer as the most risky case for all three metals in comparison with others

Use of horizontal flow roughing filtration in drinking water treatment

In order to evaluate the feasibility of implementation of horizontal-flow roughing filtration for drinking water treatment a pilot was designed and run at the bank of Zayandehroud river near the village of Chamkhalifeh. Pilot running was performed in summer 2003 [July, August and September], when the quality of river water was in relatively worst condition. The filter is comprised from three different parts which are separated with perforated baffles. Each compartment is filled with some local sand and gravel considering a special decreasing size regime. The overall function of the filter in removing turbidity and total suspended solids is acceptable. Additionally, iron, manganese and color and coliform removal are also been covered to some extent. Achieved results in this study shows that horizontal-flow roughing filtration may be considered as a packed, low-cost and efficient pretreatment process incase surface water is used as water supply for treatment. Furthermore, when small scale societies are considered and when no major pollutants exist in the water supply as the case in this study this system may be posed as a total treatment system, in which treated water exited from the filter may be sent to distribution network after a simple post chlorination

Biological nitrate removal form water resources

During the recent decades, the increasing trends in nitrate ion concentration in ground water sources have meant more research to find effective procedures for the prevention of even more water contamination by nitrogen sources. In this study a pilot was designed to examine the application of biological method for eliminating nitrate from the water of well No.903 of Mehrabad Airport, Tehran, Iran. Design, installation and running processes were done from April to November 2003. A fixed biological bed containing five-centimeter trunk pipes 16 mm in diameter were installed in the reactor and the system was operated with upflow current. Instead of Methanol, Acetic acid was used as the carbon source because of its easier acceptance by the public, lower price and availability as well as easier storage. The pilot was run in different hydraulic retention times from 48 h up to one hour. Considering economical, operational and maintenance factors, retention time of 2 h was determined to be optimum, in which 77% nitrate removal was achieved. Considering a ratio of 2 for COD/N, inlet COD of about 140 mg/L and the optimum retention time, COD removal of about 80% is also accomplished in this process. The amount of nitrite concentration, pH values, COD and turbidity is also evaluated versus different hydraulic retention times

Site selection of municipal solid waste landfills using analytical hierarchy process method in a geographical information technology environment in Giroft

Municipal solid waste generation is among the most significant sources which threaten the global environmental health. As an ideal selection depends on considering several independent factors concerning land use, socio economy and hydrogeology, the use of a multi criteria evaluation method seems inevitable. Taking benefit of geographic information system as a tool in combination with geographical information technology, equips the spatial decision support systems in appropriate site selection of sanitary landfills. The present study involves a kind of multi criteria evaluation method under the name of weighted linear combination by using geographical information technology as a practical instrument to evaluate the suitability of the vicinity of Giroft city in Kerman province of Iran for landfill. Water permeability, slope, distance from rivers, depth of underground watertable, distance from residential areas, distance from generation centers, general environmental criterion and distance from roads are the criteria which have been taken in to consideration in the process of analyzing. Superposing all of the raster type layers including geomorphologic, hydrologic, humanistic and land use criteria in land suitability, the final zoning of appropriate, fairly appropriate and inappropriate districts have been identified. Considering relative priority of all criteria in comparison with others, a specific weight is designated to each criterion according to their total influence on the whole process of decision making. The results from the application of the presented methodology are zones for landfill with varying zonal land suitability. Finally the zones will be ranked in descending order to indicate the priority of different options in front of the eyes of decision makers. The results achieved by this study may help policy makers of Giroft city by a variety of options for being considered as sanitary landfill locations

Solid waste management in Tabriz petrochemical complex

Tabriz petrochemical complex is located in the northwest of Iran. Major products of this industry include raw plastics like, polyethylene, polystyrene, acrylonitrile, butadiene, styrene, etc. Sources of waste generation include service units, health and cure units, water, power, steam and industrial processes units. In this study, different types of solid waste including hazardous and non hazardous solid wastes were investigated separately. The aim of the study was to focus on the management of the industrial wastes in order to minimize the adverse environmental impacts. In the first stage, locating map and dispersion limits were prepared. Then, the types and amounts of industrial waste generated in were evaluated by an inventory and inspection. Wastes were classified according to Environmental Protection Agency and Basel Standards and subsequently hazards of different types were investigated. The waste management of TPC is quite complex because of the different types of waste and their pollution. In some cases recycling/reuse of waste is the best option, but treatment and disposal are also necessary tools. In this study, using different sources and references, generally petrochemical sources, various solid waste management practices were investigated and the best options were selected. Some wastes should be treated before land filling and some of them should be reused or recycled. In the case of solid waste optimization, source reduction ways were recommended as well as prior incineration system was modified

Evaluation of the quality and self purification potential of Tajan River using Qual2E model

Tajan River is among significant rivers of Caspian Sea water basin. Pollution sources that threaten the quality of water in Tajan River may be classified in to two categories namely point and non-point sources. Major pollutants of latter category are Mazandaran wood and pulp, Paksar dairy products and Sari Antibiotic production factories, as well as 600-dastgah residential area. On the other hand, non-point sources whose waste is considered as a distributed load consist of Sari municipal wastewater and agriculture-related pollutants that are drained towards the river. In order to model the quality of river flow, Qual2E model is taken in to consideration. Considering TDS, the river quality is completely acceptable in cold seasons. However, in spring and summer the value of this parameter is increased and this causes some restrictions in the use of this water for irrigation of specific sensitive crops. Agricultural activities and consequent irrigated waters are the major causes of higher reported TDS values in warm seasons. Current status of DO is completely acceptable and this is highly related to the relative high value of width on depth ratio along the river. BOD and COD locate in a fairly poor condition. Quality deterioration is more noticeable in cold seasons. Higher rate of precipitation and consequent greater runoff generation towards the river basin justify the relative increase of mentioned parameters in fall and winter. Generally, non-point pollution sources are more contributed in deterioration of Tajan River water quality