Journal of Environmental Studies
Year:2009 | Volume:34 | Issue:48|Papers Count:16

The influence of environmental variables on trace heavy metal partitioning has been widely investigated by means of batch reactor experiments, where the interactions between water, sediments and heavy-metal ions differ from those in natural conditions. Since advection, which is an important factor in sediment and pollutant transport, is ignored in TST (Turbulence Simulation Tank) experiments, this technique does not exhibit good simulations of the natural conditions. To get enhanced simulations for this condition, a circular flume, which is well known device in cohesive sediment transport investigations, was used in this study. The kinetic sorption of cadmium (Cd) was investigated in a circular flume and by batch reactor experiments, and variations of cadmium concentration with time in a water column and a sediment layer were measured. It was found that sediment motion can affect the adsorption kinetics. The results show that the equilibrium sorption and sorption rate will be over estimated by batch reactor experiments. Therefore, considering natural condition of sediment movement in studying transport transformation modeling of heavy metal pollutant is necessary. The effects of EC, pH, temperature, sediment concentration and cadmium concentration were also investigated through the experiments. Results show that the amount of adsorbed Cd in unit weight of the sediment increases by increasing Cadmium concentration, but the removal percent of Cadmium will be decreased. The results also indicate that the amount of adsorbed Cd in unit weight of sediment will be decreased by increasing sediment concentration; however the total removed Cadmium is increased. Increasing temperature will increase the amount of adsorbed Cadmium by unit weight of sediment. Even though previous investigations, used deionized water, show that pH over 6 has no significant effect on sorption, but as we know in natural condition increasing pH may result in CaCo3 precipitation. The results indicate that precipitated CaCO3 increases the amount of removed Cadmium and decreases the equilibrium time. In fact, precipitation of CaCo3 seriously increases the amount of the removed Cadmium and the equilibrium time. Therefore sorption by CaCo3 must also be taken into account in the heavy metal transport transformation modeling.

Unaccounted-for-water is a misleading term long used by water industry. Unaccounted-for-water includes unmeasured volume of water that run out of access from supply to end consumer and consequently leads no revenue for supplier. Examples of water losses are: meter inaccuracies, illegal connection and unauthorized usage of water, abnormal meter reading, reservoir seepage and leakage, reservoir overflow, underground leakage, pipe breaks, unwanted problem in the water treatment process, malfunction of distribution system controls, water consumption of hydrant. In domestic water network system, Meter inaccuracies are one of the most important parts of Unaccounted-for-water. Through meter inaccuracies water consume by consumers but there is no payment. So many parameters could cause meter inaccuracies: erosion parts of meter, high water and environment temperature, suspended solid in inlet water, impure filter, low ended gears and unsuitable keep of meter in store. The solution for survey of meters in water system is meter testing. In this research a part of Varamin with 6000 subscription and 4500 healthy meters was chosen as pilot of studies. One percent of meters choose randomly and the results were statistic analyzed .The results generalization to the whole city and total Unaccounted-for-water was calculated. According to the results repair meter after 5 or 6 years is uneconomic and if after the test error of meter was found it should be changes with new one. In this region most of changing meter is repaired meter .before using meter the new meter and repaired meter should be test in the workshop and if has any problem should be back to the factory.87.5 percent of meter in the pilot area has no physical losses, 6.25 percent was in the standard limit and 6.25 percent gives more money to the supplier.

Up flow anaerobic sludge blanket (UASB) treatment has proved its efficiency among other treatment methods especially for hardly degradable wastewaters such as industrial wastewaters and leachate. UASB is a widely used reactor with a resistance biomass. Waste landfills' leachate is one of the most polluted wastewaters which cause great concerns due to landfill implementations for municipal solid waste management. One of its impacts is affecting underground and surface waters. Always major tasks are done to improve leachate quality and minimize its quantity by controlling landfill influents (waste and water) and effluents (gas and leachate) but leachate generation is inevitable and large areas of soil and water can get polluted by a small amount of that. Thus, regarding these issues, legislations are going to get stricter so has made leachate treatment compulsory.A UASB pilot plant was established to examine the effects of different parameters on the anaerobic treatment of municipal solid waste (MSW) leachate in both batch and continuous operation. The pilot plant was designed based on the ability of the selected system and normal organic loading rate (OLR) using diluted leachate from Tehran's solid waste landfill. In the first stage (Batch operation), different COD concentrations from 1200 up to 6443 mg/l and Organic Loading Rate (OLR) of 1.36 to 6.6 kg COD/m3.d and Hydraulic Retention Time (HRT) of up to 21.6 hours were examined. In continuous operation, inlet COD and OLR were increased up to 25960 mg/l and 30kg COD/m3.d respectively. Results show that there is 90% efficiency in COD removal for batch situation where OLR is 4.48 kg COD/m3.d and inlet COD is 4000 mg/l. In continuous regime with OLR of 22.6 kg COD/m3.d and COD of 20000 mg/l and 21.2 hours of HRT and 38.8 hours of circulation, COD removal efficiency was raised up to 63.5%.

Municipal solid waste (MSW) composts are being produced now in different cities of Iran. Composting has been an attractive solution for MSW disposal in several municipalities because disposal of MSW is a difficult task in some area of Iran. However, poor quality of compost is one of the most important problems. Iran compost quality is studied in This research. Several compost samples were selected for the research including: six ordinary MSW compost samples from Tehran, Mashhad, Isfahan and Tabriz Compost Plants as well as three enriched MSW compost samples. Studied parameters were heavy metals (Cu, Zn and Pb) Electrical conductivity (EC), pH, carbon-nitrogen ratio (C/N), Nitrogen/ Potassium/ Phosphate (NPK) percent and Organic matter (OM). Due to lack of Iranian quality standards for MSW compost, it has been used European standards in the study. In six samples of MSW compost, characteristics of C/N, pH, EC, NPK and OM were varied 12-30, 6.95-7.45, 1830-2170 (?s/cm), 1.78-3.97 (%) and 23-55.5 (%) respectively. In addition, concentration of Cu, Zn and Pb for the mentioned samples were between 656-780, 994-1222 and 286 (mg/kg), respectively. However, for three enriched compost samples C/N, pH, EC, NPK, OM, Cu, Zn and Pb were between 19.5-28.7, 6.37-6.87, 1050-1250 (?s/cm), 1.35-2.07 (%), 15-35 (%), 287-309 (mg/kg), 513-612 (mg/kg) and 109-161 (mg/kg), respectively. Low C/N (especially in Tehran compost), high level of heavy metals (particularly Cu and Zn), Low NPK content and relatively high electrical conductivity are the most important reasons for poor quality of compost in Iran. In the studied parameters, only pH and organic matter (OM) have acceptable ranges. Therefore, the low quality of composts available in Iran market suggests an urgent need for establishing quality assurance procedures and also preparing compost quality standards in the country. Moreover, if the existing composting processes are modified, the compost quality will be better and thus demand for compost consumption will increase.

Today the industrial wastes are one of the main problems in the developing countries. Discharging the industrial wastewater into environment is harmful for human health and other living creatures. Thus decreasing of the pollution load of waste waters is an important environmental issue. Adsorption of chemical oxygen demand by biomass wastes can be a proper and low cost method for COD removal from industrial wastewater, Since these materials are abundant in nature and useless. The use of carbon prepared from date pits and nutshells capacity to adsorb COD from aqueous solutions are studied. The purpose of this study is to determine optimum conditions for adsorption of COD of fiber wood wastewater on mentioned adsorbents. The COD adsorption experiments were carried out to analyze the influence of pH, sedimentation time, contact time, initial COD concentration and adsorbent dosage. Experiments show that efficiency of COD adsorption is optimum at 0.5 hour sedimentation time and 2.5 hour contact time. Also results suggest relation between initial COD concentration and adsorption and concentration of adsorbent is uniformed. The higher the concentration is, the higher adsorbent dosage is required. At optimum conditions, 1 g/lit of nutshell carbon and date pit carbon can respectively remove approximately 19 & 11 percent of COD. The optimum pH for nutshell activated carbon is pH=2 and for date pit activated carbon is pH=7. At optimum conditions the maximum COD removal by nutshell activated carbon is 57% and by date pit activated carbon is 54%. Other experiments on distillated water shows that nutshell activated carbon itself increase the COD of wastewater but the date pit activated carbon dose not have any effect on COD. The SEM pictures of carbons (magnitude 500×) before & after adsorption process can show the operation clearly.

Bam, which is located in the south eastern part of Iran, east of Kerman province, is a desert city with its special natural and cultural landscapes, which is different in many ways from all other desert cities in Iran There has always been a balance between cultural and natural elements in Bam. One of the unique natural elements of Bam is its rich underground water reservoirs, which originates from the special formation of the waterways of this region .Two of the most valuable cultural dimensions of Bam are Qantas and palm groves. The main purpose of this article is to recognize natural and cultural textures, how they coincide and connect, and causes of disorders in the balance of this relationship over the course of time. After a review was made of written and pictorial descriptions of Bam before and after the quake and additionally, field work and map analysis were done, and the relevant data was put together with the natural parameters, including hydrology (surface and underground), geomorphology, and plant cover, and also cultural parameters, including the structure of gardens and the city a recognition was made possible of the natural and cultural textures and how they connect over time. In this way, suitable patterns for improvement and restoring a balance between the two textures were identified. Also by preparing and presenting maps from before and after the quake, layering and superimposing these layers, the decreasing balance between natural and cultural textures and the cause of their disorder have been recognized. Finally this article tries to show solutions for restoring a balance between natural and cultural textures and also maintaining this balance over time .Methods used here can be generalized as methods for other desert cities which are an inseparable and coordinated part of their natural texture.

Human comfort and public health condition have directly depended on the meteorological conditions including temperature, sunlight and relative humidity. The apparent temperature index has recently been introduced as a measure for evaluating the combined effects of temperature and relative humidity on human comfort. In this study the maximum and the average values of this index was determined in four Iranian cities comprising Shiraz, Bandar Abbas, Birjand and Ardebil in daily and monthly scales. It has shown that, due to simultaneous increase of temperature and relative humidity in Bandar Abbas, apparent temperature was significantly higher than the measured temperature. During summer the residents of this city are, therefore, subjected to intense heat stress and its associated bad effects. Due to the low values of relative humidity in Shiraz and Birjand the calculated apparent temperature of these cities was found to be lower than measured values by thermometer. The given results have indicated that, for some days of June and July the risk of heatstroke, sunstroke and muscle contraction are serious for Bandar Abbas, Shiraz and Birjand, respectively. The values of daily maximum apparent temperature revealed that for some circumstances people's health is seriously at risk due to high temperatures between 13:00 and 15:00 afternoons.  

Prosopis cineraria (L.) Druce (Kahour in Persian) is a native and indicative species of Saharo-Sindian region. Prosopis forest in Iran extends from the beach of Persian Gulf and Oman sea in Boushehr, Hormozgan and Sistan-Baluchistan provinces to south of Kerman province. In this research ecological conditions of Prosopis such as floristic diversity, climate, soil and the biomass were studied. Its distribution expands in warm hyper-arid and arid to temperate hyper-arid climate. Mean of annually precipitation the study areas are at about 45-200mm, the absolute maximum is 50°C and the absolute minimum temperature is -4°C. Soil characteristics of Prosopis forest include electrical conductivity, pH, lime, organic carbon; Sodium Adsorption Rate and gypsum were studied. The results detect soil of forest is young. Soils have slightly saline to saline-sodic properties, with non appreciable organic matter. Although the calcic horizon was diagnosed in all of soil profiles of prosopis forest but the gypsic horizon was found rarely. Soil texture is coarse to moderate. Soil reaction is neutral to slightly acidic. In recent years, the vegetation areas of Prosopis degraded severely due to clearcut and change the land use to agriculture, livestock feeding and burning to charcoal.

Coastal area sensitivity assessment is in fact, the assessment of an extraordinary ecological rich region, in spite of existing environmental polluting factors. This study has been based on established criteria and values. The aim of this sensitivity assessment has been to give objectivity to the Boushehr province coastline region, so as to be able to pinpoint areas requiring ecological conservation. For this purpose, the studied limit was identified by satellite imagery in terms of shoreline and maximum extent of water approach into land along with consideration of the characteristics of nearby coastal villages as above mentioned limit. The coastal area being evaluated was comprising an area of 384810 hectares In this research the blueprint of a new model was planned with use of Analytic Hierarchy Process method backed by the Arc GIS Software program. In the new model the value of influencing sensitivity factors were not applied in the same manner but by determining weight coefficients, the value and importance of each factor was determined according to the amount of sensitivity inflicted on the specified environment. In total, in the area under consideration, 2994.21 hectares were defined as very high sensitivity areas, 2701. hectares high sensitivity areas, 42124.19 hectares medium sensitivity areas and 290056.80 hectares low sensitivity areas.

The quality of environmental impact assessment (EIA) findings, as a decision support system, has always been a function of the extent of its boundaries. Meanwhile, boundaries of a study area can be delineated physically or non-physically according to the EIA working units or methodologies. Six case studies have been conducted to consider the study areas of variety of EIAs namely, visual, cumulative, forest-degradation due to population growth, air and river pollution. For each case study, we considered dominant constrains and EIA objectives that were desired in the EIA procedure. In the end, frameworks were introduced to delineate the boundary of study area in different EIAs. For instance, the boundary in a highly mountainous area was delineated according to constrains of topography, water-line of a dam lake for EIA of a dam, and software limitations and interfaces for air pollutant dispersion assessments around stack gas of a thermal power plant. Overall, a complete boundary-delineation in an EIA can be achieved, if several boundaries (physical/non-physical) considered at once. For example, if the EIA study area is located near a national park, the whole park must be included to assess the project environmental impacts on the national park besides national and international considerations.

This research was carried out based on systematic analysis approach for evaluation of ecological resources capability of Kasilian representative catchment for agricultural land use. The study area is located in southern of Mazandaran province. In this study we used topography digital data, paper maps, climatology data, satellite images and GIS, database and spreadsheet software. The process of study was including: ecological resource identification, database creating, data processing, integration of data, and at last modeling of ecological capability for agricultural activities. For creating environmental unit map, the permanent ecological resources were overlaid with binary method and in each stage of the integration process the overlaid layers were coded by Makhduom’s method. At last, the attribute table of environmental unite map was completed with impermanent resources data. Then each unit of environmental unit map was modeled by linear equation of ecological model for agriculture. The Result of this study indicates that the study area was formed of 437 environmental units. Attention with %26 of present Land use of the study area was agricultural land use, but it showed the environmental units have at least one limitation for agricultural activities. The limitation factors for agricultural Land use in study area included: air temperature, rainfall, pH of soil, soil depth, soil formation, soil aggregation, soil drainage, soil texture and slope of the farmland.

Soil moisture is one of the critical parameters in climatic, ecological and hydrological modeling and vegetation growth. Soil moisture is important for environmental studies but due to ground-based point measurement of soil moisture is expensive and impractical for watershed measurement, this parameter is not be used widely to simulate and predict models. Overall and uniform view on different part of land, repetitive photography from wide and inaccessible areas along with data with regular periods and decrement effects of plans on environment are important criteria's of remote sensing. Rangeland growth is heavily functioning of the water availability therefore the vegetation index from satellites may respond to the change of soil moisture. We used MODIS sensor images with the consideration of economical aspects, availability of images and high radiometric, temporal and spatial resolution to estimate the surface soil moisture. MODIS images were provided by Iranian Space Agency for the day's availability of soil moisture field data matched by satellite images. Radiometric and geometric correction was conducted by orbital parameters on all images and the images were converted to BIL format and shifted in relation to accurate boundary of Caspian sea. Using bathymetry map of Caspian Sea, atmospheric correction was conducted by dark pixel method. This case study analyzes the correlation the surface soil moisture measured gravimetric sampling and MODIS NDVI (250m by 250m), compares the collected coincided and lagged soil moisture and MODIS NDVI. Also estimates the soil moisture using NDVI by linear regression models during growing season (April-Aug) from 2003 through 2005 in arid and semi arid rangeland in Khorasan Razavi Province. NDVI shows lag to soil moisture because of vegetations response lag it. Results show that surface soil moisture in arid and semi arid rangelands has moderate correlation with simultaneous and lagged NDVI and can be estimated using NDVI during growing season. Stronger relations can be obtained with surface soil moisture data that are lagged by 2 weeks with respect to the vegetation index.

Alfalfa and maize are important agricultural plants for animal consumption. In this survey, accumulation quantity of heavy metals (Fe,Zn,Mn,Cd,Pb,Ni,Cr) in plants irrigated by sewage and well water were compared statistically together and with normal or standard(permeable) limits in plants or foraging, during 2005. The results were as following 1-Maize: the value of accumulation in maize irrigated by sewage is nearly 1.5 times of the maize crop irrigated by well water. Apart from Mn and Zn, the accumulated quantities of heavy metal were more than normal and standard limits of maize crop. In the corn and maize grains Ni, Cr, Pb, and Zn were less than permeable limits and Mn and Cd were more than permeable limits. In the maize crop irrigated by sewage cadmium accumulation in upper organs at Dehkhair & Salehabad and in the seed and corn at the all of the three regions and lead accumulation in the upper organ in Salehabad and Talebabad, and in the root in Dehkhair & Salehabad and Iron in the root at the all of the regions were more than permeable foraging limits. Transition coefficients to upper maize organs at the three regions were more than standard limits, and Pb had the maximum value.2- Alfalfa: accumulated amounts of heavy metals in the first mowing were more than those amounts in the second mowing totally. Accumulated amounts (apart from Ni,Cr and Pb in Talebabad and pb and Zn in Dehkhair ) in the first harvest of alfalfa irrigated by sewage were more than of these amounts in alfalfa irrigated by the well water. Accumulated limits of Fe in Salehabad and Dehkhair, Cd in Dehkhair, Cr and Pb In the all of these regions at the first mowing were more than permeable limits of plant growth. The heavy metals accumulation reduced in the second mowing but the amounts of Cd and Pb in Dehkhair and Pb in the all of the surveyed regions were more than permeable limits of plant growth. In the Alfalfa irrigated by sewage, Cd accumulations in all of the surveyed regions were more than permeable foraging limits. In survey aboat amounts of transition coefficient Pb had minimum amount of transition from soil to upper organs. Heavy metal transition, especially for Cd and Fe, reduced in the second mowing.