Showing papers in "International journal of water resources and environmental engineering in 2010"

Experimental study of methylene blue adsorption from aqueous solutions onto carbon nano tubes

Abstract: In this work, batch adsorption experiments were carried out for the removal of methylene blue as a basic dye from aqueous solutions using carbon nanotubes (CNTs). The effects of major variables governing the efficiency of the process such as, temperature, initial dye concentration, CNTs dosage, and pH were investigated. Experimental results have shown that, the amount of dye adsorption increased with increasing the initial concentration of the dye, CNTs dosage, and temperature. The dye removal using 400 mg L-1 of CNTs was more than 90%. This dosage (400 mg L-1) was considered as the optimum dosage of CNTs to remove methylene blue. The adsorption kinetic data were analysed using pseudo-first-order, pseudo-second-order and Elovich models. It was found that the pseudo-secondorder kinetic model was the most appropriate model, describing the adsorption kinetics. Adsorption isotherm of methylene blue onto the CNTs was determined at 290, 300 and 310 K with 10 mg L-1 as initial concentration of methylene blue. Adsorption equilibrium was attained within 120 min. Equilibrium data were fitted to the Langmuir, Freundlich, Temkin and Sips isotherm models and isotherm constants were determined. The equilibrium data were best represented by the Sips isotherm model. Thermodynamic parameters such as changes in the free energy of adsorption (�G�), enthalpy (�H�) and

Cadmium sorption by Moringa stenopetala and Moringa oleifera seed powders: Batch, time, temperature, pH and adsorption isotherm studies

Abstract: There is a widespread recognition that the presence of heavy metals such as cadmium in water is hazardous to the environment and human health and their discharge into surface waters is of great concern world wide. The use of natural coagulants such as Moringa for heavy metal removal from water replacing expensive imported synthetic coagulants is particularly appropriate for agro-based developing countries such as Malawi. This study was aimed at investigating the potential of Moringa stenopetala and Moringa oleifera in the removal of cadmium(II) ions from water. The potential of M. stenopetala for cadmium removal was investigated by means of jar test beakers. With an initial cadmium concentration of 7 mg/l, M. stenopetala seed powder, at a dose of 2.50 g/100 ml, reduced the concentration of cadmium by 53.8%. Comparison of removal capacities between M. stenopetalaand M. oleifera indicated that M. stenopetala was more effective than M. oleifera in removing cadmium from water (p < 0.05). Increasing initial cadmium concentration, agitation time and ionic strength reduced cadmium removal. Equilibrium sorption was attained at pH 5 where maximum cadmium removals were 82.7 and 70.7% using M. stenopetala and M. oleifera respectively. There was a reduction in cadmium removal between 0 to 60°C for M. stenopetala and 0 - 40°C for M. oleifera before increasing with subsequent temperature increases. It was also shown that cadmium sorption at 30°C and pH 3 for the M. oleifera could best be modelled by the Freundlich isotherm whereas the Langmuir model is slightly better than the Freundlich isotherm in the case of the M. Stenopetala. The energies of adsorption from Dubinin-Radushkevich models have indicated that cadmium removal using both powders is based on physisorption. The results indicate that M. stenopetala and M. oleifera have potential in cadmium remediation of polluted waters. Key words: Cadmium, Moringa oleifera, Moringa stenopetala, water pollution, remediation, Freundlich, Langmuir, Dubini-Radushkevich isotherms.

Prioritization of micro watersheds on the basis of soil erosion hazard using remote sensing and geographic information system

Abstract: Degradation of agricultural land by soil erosion is world wide phenomenon leading to loss of nutrient-rich surface soil, increased run off from more impermeable subsoil and decreased water availability to plant. Thus estimation of soil loss and identification of critical area for implementation of best management practice is central to success of soil conservation programme. In this study universal soil loss equation (USLE) interactively with raster-based geographic information system (GIS) has been applied to calculate potential soil loss at micro watershed level in the Konar basin of upper Damodar Valley Catchment of India. The main advantage of the GIS methodology is in providing quick information on the estimated value of soil loss for any part of the investigated area. The rainfall erosivity R-factor of USLE was found as 293.96 and the soil erodibility K-factor varies from 0.325 - 0.476. Slopes in the catchment varied between 0 and 83% having LS factor values ranging from 0 - 6.7. The C-factor values were computed from existing cropping patterns in the catchment and support practice P-factors were assigned by studying land slope. Average annual soil erosion at micro watershed level in Konar basin having 961.4 km2 areas was estimated as 1.68 t/ha/yr. Further, micro watershed priorities have been fixed on the basis of soil erosion risk to implement management practices in micro watersheds which will reduce soil erosion in Konar basin. Key words: Remote sensing, soil erosion, geographic information system, universal soil loss equation, priority.

Evaluation of the radiation dose from radon ingestion and inhalation in drinking water

Abstract: Radon and its radioactive progenies in indoor places are recognized as the main sources of public exposure from the natural radioactive sources. The tap water used for drinking and other household uses can increase the indoor radon level. In the present research, drinking water samples were collected from various places and supplies of public water used in Mashhad city which has about 4 million population. Then radon concentration has been measured by PRASSI system three times for each sample. Results show that about 75% of water samples have radon concentration gathered than 10 Bq/L which advised EPA as a normal level. According to measurements data, the arithmetic mean of radon concentration for all samples was 16.238 ± 9.322 Bq/L. Similarly, the annual effective dose in stomach and lung per person has been evaluated in this research. According to the advice of WHO and EU Council, just 2 samples induced the total annual effective dose greater than 0.1 mSv/y. Key words: Radon, effective dose, drinking water, PRASSI system, Mashhad city.

Performance and kinetic evaluation of phenol biodegradation by mixed microbial culture in a batch reactor

Abstract: Mixed microbial culture collected from effluent treatment plant of a coke oven industry has been studied for its phenol biodegrading potential under aerobic condition in a batch reactor. The result showed that, after acclimatization, the culture could biodegrade up to 700 mg/l of phenol. The results showed that specific growth rate of microorganisms and specific substrate degradation rate increased up to 300 mg/l of initial phenol concentration and then started decreasing. The biodegradation kinetics is fitted to different substrate inhibition models by MATLAB 7.1©. Among all models, Haldane model was best fitted (Root Mean Square Error = 0.0067) for phenol degradation. The different biodegradation constants (Ks, Ki, Sm, mmax, YX/S, kd) estimated using these models showed good potential of the mixed microbial culture in phenol biodegradation. Key words: Mixed culture, phenol biodegradation, kinetics, inhibition model.

Prediction of water table depth in a hard rock basin by using artificial neural network

Abstract: The objectives of this study were to determine the factors that influence and control the water table fluctuation in a specific geomorphologic situation, to develop a forecasting model and examine its potential in predicting water table depth using limited data. Prediction of region specific water table fluctuation would certainly guide the way towards conceiving, designing and taking scientific measures to ensure sustainable groundwater management. Analysis of change in groundwater table depth, groundwater flow directions within the watershed showed that the influencing factors of rainfall, groundwater draft from near by structures and the resulting fluctuation in groundwater table depth were well correlated in a specific geological situation. Models for prediction of water table depth were developed based on artificial neural networks (ANNs). The study employed multilayer feed forward neural network with backpropagation learning method to develop the model. The neural networks with different numbers of hidden layer neurons were developed using 4 years (2005 - 2008) monthly rainfall, potential evapotranspiration (PET), and water table depth from nearby, influencing wells data as input and one month ahead water table depth as output. The best model was selected based on the root mean square error (RMSE) of prediction using independent test data set. The results of the study clearly showed that ANN can be used to predict water table depth in a hard rock aquifer with reasonably good accuracy even in case of limited data situation. Key words: Water table fluctuation, rainfall, groundwater draft, ANN.

Modeling hydropower plant system to improve its reservoir operation

Abstract: One way of improving water management is increasing the efficiency of utilization of dam reservoirs. Even small improvement in reservoir operation can lead to large benefits. But there is no universal solution for reservoir operation problems. Hence, it is necessary to study the system and determine optimal reservoir operation guides for each scheme. In the present study, Melka Wakana Hydropower Plant in Ethiopia has been modelled and studied. The tool used was Powersim Simulation software. Mean monthly data of reservoir inflow, evaporation rate, recorded energy production; recorded discharge (turbine flow) and recorded reservoir elevation were used as time series input data. Different variables and relationships between variables were defined along with the constraints. After developing and calibrating the model successfully, detailed simulation analysis has been carried out by controlling reservoir releases for energy production, taking into consideration; increasing yearly energy production and improving the uniformity of monthly energy production. The results of the simulation analyses indicated that the yearly energy production was increased by 5.67% while evaporation loss was reduced by 38.33%. But this power plant still produces below its design capacity by 12.21%.The uniformity of monthly energy production from this plant was also improved. The new reservoir operation guide curve has been developed for the optimum energy production from this plant. Key words: Guide curve, simulation model, reservoir operation, hydropower, energy production, water resources management.

Water quality of domestic wells in typical African communities: Case studies from Nigeria

Abstract: Several African communities obtain their domestic water supplies from dug wells and this study takes Ibogun, Pakoto and Ifo communities in Ogun State, Nigeria as being typical. The objective is to assess the quality of the water supply from these dug wells, ascertain the contamination problems that may confront the consumers, and provide appropriate remedies. Twenty dug wells were randomly selected in each community. Water samples from the selected dug wells were collected during July - August 2009. The samples were checked for odour, colour and taste; and through standard methods, they were analyzed for pH, total solids, total hardness, chlorides, sulphate, nitrates, magnesium, calcium, manganese, sodium, copper, zinc, iron and lead; total viable count, total coliform count, faecal coliform count and faecal streptococci count. Most of the pH values of the samples were outside the recommended range of 6.5 – 8.5 for drinking water. Predominantly, the ionic dominance pattern observed were Na > Ca > Mg and HCO3 > Cl > SO4, indicating typical cationic characteristics and anionic characteristics of groundwater. For total solids and total hardness, guideline values were largely met. Levels of iron did not exceed the WHO guideline value of 0.2 mg/l for Fe in drinking water. Mean levels of Mn measured were far in excess of the average of 0.01 mg/l for fresh water, while in relation to the WHO guideline value of 0.4 mg/l for Mn in drinking water, the levels measured were low. Generally, the levels of nitrates, sulphate, chlorides, magnesium, manganese and iron were moderately high, but the WHO guidelines were not exceeded. The WHO guidelines for microbiological quality of water were met in several cases. Matching of non-technical and techno-social remedial measures is recommended. These include sensitization of the populace on merits of qualitative domestic hygiene and environmental protection practices such as cleaner compounds and strict enforcement of environmental protection laws. Key words: Dug wells, water, physico-chemical analyses, microbial analyses.

Industrial sludge based adsorbents/ industrial by- products in the removal of reactive dyes - A review

Abstract: Adsorption has been an effective separation process for non-biodegradable pollutants. Study of recovery of dyes reveals adsorption as an efficacious process. Many textile industries use commercial activated carbon for the treatment of dye waste. The current research is focused on the need to alternate commercial activated carbon with a cost effective, potential adsorbent. The major limitations in using commercial activated carbon in large scale are its regeneration and high cost of operation. Many researchers have studied the feasibility of using low cost adsorbents derived from natural materials, industrial waste materials, agricultural products and biosorbents as precursors. Numerous works have been reported on these adsorbents being used in the removal of heavy metals and dyes. This paper reviews the development of different industrial sludge/by products as adsorbents under various activation methods. The decolourization of reactive dye solutions by the developed adsorbents under batch mode is also discussed. Based on the reviews, development of activated carbon from preliminary tannery sludge is suggested by various activation methods. Key words: Adsorption, reactive dye, activated carbon, tannery sludge.

Hydro-meteorological correlations and relationships for estimating streamflow for Gangotri Glacier basin in Western Himalayas

Abstract: This study investigates the relationships between hydrological and meteorological data collected near the snout of Gangotri Glacier, Indian Himalayas for the different ablation seasons (May - October). The complete analysis employs a hydro- meteorological data series for a period of 7 years (2000 - 2006). The first 5 years data (2000 - 2004) was used for determining correlations, lag-cross-correlations and multivariate regression analyses between daily mean discharge, daily mean temperature and daily rainfall , whereas, last 2 years data (2005 - 2006) was used to simulate the daily discharge using established relationship. Changes in correlations between discharge and meteorological variables, lagged by 0 - 3 days, were determined. Variations in the physical features of the glacier, weather conditions, and precipitation and its distribution with time over the basin account for changes in correlations. The analysis suggests a very high discharge auto-correlation for each individual year and for the combined data series of 5 years. The substantial storage of melt water in the glacier body and its delayed response of the runoff attribute to the high dependency of a particular day discharge on its pervious day’s discharge. A comparison of correlations between discharge and temperature, and discharge and rain shows that temperature has a better correlation with discharge series for all the years. To estimate the discharge for Gangotri Glacier basin, multiple linear regression equations were developed separately for each ablation season and a combined data set of 5 ablation seasons. The generalized regression equation developed using stepwise regression approach for the data set of 5 years (2000 - 2004) was adopted to estimate daily mean discharge for 2005 and 2006. For both simulation years, the simulation efficiency was very high (R 2 = 0.96). It is found that discharge of study basin is well represented Qi-1 (1-day lagged discharge) and Ti, Ti-1, Ti-2 (0 - 2 days lagged temperature) and Ri (0-day lagged rain). Such relationships can be used for filling the missing discharge data as well as for forecasting of discharge.

Making a case for systems thinking approach to integrated water resources management (IWRM)

Abstract: While definite benefits could be gained from integrating the management of natural and human systems, taking into account the effects of human activities on the environment, the task of operationalising and implementing this approach in practice represents an enormous challenge. Some limitations highlighted include the definition of integrated water resources management (IWRM) itself, where it appears to be broad, all-encompassing and impressive but contains ‘‘lofty phrases’’ that have little practical importance for either present or future water management practices. This paper makes recommendations to uptake and incorporate the systems thinking approach (STA) in IWRM decision making processes, an approach envisaged to be more participatory and also process-oriented. Incorporation of socio-economic dynamics is also recommended, with a suggestion that the biophysical relationships like interactions in a basin between water, the human population and settlements should be analysed to the extent possible. Key words: Integrated water resources management, operationalising IWRM, socio-economic dynamics, systems thinking approach.

Assessment of water quality and impact of effluents from fertilizer factories to the Lakhya River

Abstract: A study was carried out in Polash and Ghorasal Urea fertilizer factories to assess the impact of effluent on water quality of the Lakhya River. Comprehensive waste water sampling by grab sampling method and flow measurement by float velocity method were carried out for five weeks (one sample per week) at five sampling stations at Polash and Ghorasal Urea fertilizer factories during June to July, 2007. Water quality samplings by grab sampling method were also carried out for five weeks (one sample per week) at four stations in the Lakhya River at the same time and River flows on the period of October 2006 to September 2007 were collected from Institute of Water Modelling. Effluents at both the factories and water sample from selected points in the river were analysed for pH, temperature, DO, BOD5, COD, NH3-N, NH4-N, TS, TSS, and TDS during June to July, 2007 at the Environmental Engineering Laboratory of Bangladesh University of Engineering and Technology, Bangladesh. The results showed that the effluents were alkaline while the level of DO, BOD5, COD, NH3-N, NH4-N, TS, TSS, and TDS relatively high and 17425-20012 kg/day Ammonia load discharged from fertilizer factories into the Lakhya River. The upstream water was near to neutral pH (average pH, 7.66 ± 0.102) with high dissolved oxygen but low in the levels of the other parameters. The river water after the effluent receiving points was basic (average pH, 8.16 ± 0.08) and the levels of other parameters were high due to heavy pollution load especially Ammonia discharged from fertilizer factories. The results suggested that water in the river was polluted and not good for human consumption. It is therefore recommended that the disposal of improperly treated or untreated wastes should be stopped to save the river water from further deterioration. Key words: Industrial effluents, Impact, river water, pollution, water quality.

Comparison of pollutant levels in effluent from wastewater treatment plants in Blantyre, Malawi

Abstract: In Malawi, the requirement to treat wastewater is underscored by the existing regulatory framework, institutional arrangements, and policy guidelines. In addition, formalized national effluent standards exist. This study was conducted to determine the pollutant levels in effluent from municipal wastewater treatment plants in the city of Blantyre, Malawi, and to compare these with Government of Malawi standards and World Health Organisation (WHO) guidelines. Data on physicochemical characteristics of the effluent was collected through a desk study. This study established that Biochemical Oxygen Demand (BOD5) and Total Suspended Solids (TSS) levels in effluent from the three major wastewater treatment works in the city are in most cases above the recommended Malawi standards and WHO guidelines. Levels for heavy metals are all lower than the recommended standards except for Cadmium, in the dry season effluent at Limbe wastewater treatment works. In view of the pollution threat posed by the high levels of BOD5 from the three works, the paper recommends that the assimilative capacity of the receiving watercourses be ascertained to determine the impact of the organic and solids loading in the final effluent upon the aquatic flora and fauna. Key words: Aquatic flora and fauna, effluent, municipal wastewater treatment, physicochemical characteristics.

Environmental flows in Bhadra River, Karnataka, India

Abstract: Environmental water requirements, also referred as ‘environmental flows’, are a compromise between water resources development and the maintenance of a river in ecologically acceptable or agreed condition. Managing environmental water flow is a complex task because the change of quantity of water occurs as the flow moves downstream. In this work, an attempt has been made to evaluate the existing conditions of the water flow in the Bhadra River at Lakkavalli, Shimoga District, Karnataka State, India and the significance of the ecosystem services through environmental flows. The possible impacts from the absence of environmental flows have also been recorded. The study involves an analysis of water flow status of Bhadra River for thirty years and also the field investigations which cover complete livelihood dependent fishermen communities and command area dependent agricultural communities. The upper catchment of the river is covered with good vegetation; the downstream of the river for 40 km has shrunken in its river bed due to the Bhadra dam, the river flow is completely irregular over a period of years. It has altered the natural flow, resulting in massive loss of riparian, aquatic habitat and water quality. Local communities are aware of the importance of environmental flows and have also realized the damages done by themselves through encroachments of flood plains and river bed for agricultural activities. More than 60% of the downstream dwellers have changed their livelihood occupations, and also migration level has increased in the fishermen communities. Communities have been impacted by irregular dry season water level fluctuations, which are characterized by extreme highs and lows, and rapid changes in water levels.

The diurnal variation of the physico-chemical parameters of a lowland river flow in a semi-arid landscape with human interferences in Zimbabwe

Abstract: Using data from southeast Zimbabwe intensive agricultural zone we investigated diurnal changes in the Runde River to discover the variations that can occur in the control and test sites of agricultural development. This should predict how the aquatic ecosystem responds when ’stressed' by human activities, such as runoff from the land. Diurnal changes were studied at a resolution of 2 h intervals between 0500 and 0600 h in the control sites and test sites of an area with agricultural development in July 2005 and 2006. The observations gave same results. The diurnal fluctuations are characterized by sharp rises and gradual declines each day. The maximal and minimal points in diurnal changes can be useful biogeochemical signatures for describing the fluvial conditions of a river in a river basin. Significant associations (R2 = 0.64, y = -1.30 x +24.93, P = 0.03) between measured dissolved oxygen concentration (mg/l) and temperature (°C) were demonstrated during the daytime only in the site above the effluent outfall. Insignificant associations (R2 = 0.04, y = -032 x +13.94, P = 0.75) between measured dissolved oxygen concentration (mg/l) and temperature (°C) were demonstrated during the nighttime in the site above effluent outfall. This suggests that there was more dissolved oxygen concentration added during the day than at night at the site above the outfall. The coefficients of determination between dissolved oxygen concentration (mg/l) and temperature (°C) for the daytime and nighttime were R2 = 0.35 and R2 = 0.29, respectively, for site below the outfall. There were almost identical regression lines demonstrated during the daytime and nighttime below the outfall, an indication that oxygen demanding wastes deplete dissolved oxygen concentration. No significant associations were found between dissolved oxygen and temperature during the daytime and nighttime below the outfall. This study indicates that fluvial conditions characterized by fluctuations in diurnal changes may be a strong signature to catchment activities but need to be looked at in conjunction with other fluvial measures such as flow rate, depth and channel discharge that may also be naturally challenging to aquatic organisms. Key words: Zimbabwe, savanna semi-arid lowland river, diurnal changes, aquatic organisms.

Assessment of the dry and wet period severity with hydrometeorological index

Abstract: The paper examines the existing condition of water resources for the basin of Camlidere dam in the vicinity of capital city of Ankara, Turkey and highlights the hydrological elements that are mostly prone to the change of atmospheric conditions. After the evaluation of environmental conditions, the standardized precipitation index (SPI), standardized runoff index (SRI) and standardized potential evapotranspiration index (SEI) have been calculated with monthly air temperature, precipitation and stream runoff records in and around the basin. The calculated index values are used for defining the hydrometeorological dryness and wetness severity in the basin named as Aggregated Drought Index (ADI). The aggregated drought index was able to clarify the long wet and dry periods with a high correlation between the North Atlantic Oscillation (NAO) and El-Nino Southern Oscillations (ENSO) indices. The determined monthly ADI values provide an indication to predict wet or dry conditions in advance for the study basin. Key words: Drought, wetness, north Atlantic oscillation, southern oscillation, aggregated drought index, camlidere dam, Turkey.

Empirical correlations for the performance of belt skimmer operating under environmental dynamic conditions

Abstract: The present study is predicting, by deducing empirical correlations, the effect of varying the operating and the environmental parameters on the performance of belt skimmer. The belt linear speed, belt inclination angle and oil film thickness are the operating parameters. The current speed and the wave height are the environmental parameters. The oil recovery rate, ORR and the oil recovery efficiency, ORE, the two most important parameters displayed the performance of the belt skimmer, are predicted by empirical correlations as function of these operating and environment parameters. Sets of published experimental data in the open literature were used to obtain these empirical correlations. Five different cases are studied. In each case two equations are deduced, one for ORR and the other for ORE. These cases covered the static and dynamic belt skimmer working conditions. The empirical correlations are obtained by using the least squares method (Regression analysis). Comparisons are performed between the results obtained, for ORR and ORE, using the deduced empirical correlations and the used experimental data. Finally, general empirical correlations, cover practical operating belt skimmer ranges, are obtained and show reasonable agreement with the experimental data. Key words: Empirical correlations, belt skimmer, performance.

A methodology of finding dispersion coefficient using computational fluid dynamics (CFDs)

Abstract: The treatment efficiency of waste stabilization pond is directly related to its hydraulic regime. The hydraulic efficiency of the pond is dependent on parameters such as the pond geometry, the location of inlet and outlet and the inlet flow velocity. Poorly designed or specified hydraulic parameters may lead to short circuiting and dead regions within the pond. This in turn impacts the dispersion coefficient. Drogue and tracer studies are often used to get actual dispersion coefficients; however, tracer studies can be costly and are therefore not practical to do frequently. The objective of this paper is to obtain the actual dispersion coefficient using computational fluid dynamic (CFD) approach (using Fluent). The CFD results are validated using an actual tracer test.

Determination of appropriate hydraulic conditions to decrease the negative impacts of Dez dam flushing operation on the

Abstract: The Dez dam is located in the Southwest Iran and was constructed in 1963, with a height of 203 m and an underground powerhouse of 520 MW, because of the high rate reservoir sedimentation, in recent years, therefore, performing flushing operations through the three irrigation gates of the dam has received great attention. Due to the release of high concentrations of sediments, on the other hand, performing such operations may cause considerable impacts downstream. The downstream limitations should, therefore, be taken into consideration during the flushing operations. In this paper, it has been tried to identify and introduce the downstream limitations of performing flushing operations for Dez dam, and to determine the most appropriate flushing hydraulic conditions in terms of discharge, concentration, and duration of such operations using model MIKE 11, so that the dam utilization system can perform these operations with the least damage to the downstream. Results show that if we take into consideration every factor involving the decision- making, then the flushing operations along with two stages of opening the irrigation gates (that is the evacuation of sediments) for 6 hours and the discharge of 30 m3/s will be the best option. The interval between the two flushing operations should be at least 6 hours. Based on the results of this paper, appropriate conditions for hydraulic flushing can be determined. These conditions will be manipulated by the responsible administration as these operations would have the least damage and cost. Key words: Dez dam, environmental impacts, sediment flushing, Mike 11 model.

Water resources management and sustainabledevelopment in Sudan

Abstract: For the thirty-nine million who live in Sudan, environmental pollution is a major concern; therefore industry, communities, local authorities and central government, to deal with pollution issues, should adopt an integrated approach. Most polluters pay little or no attention to the control and proper management of polluting effluents. This may be due to a lack of enforceable legislation and/or the fear of spending money on the treatment of their effluent prior to discharge. Furthermore, the imposed fines are generally low and therefore do not deter potential offenders. The present problems related to water and sanitation in Sudan is many and varied, and the disparity between water supply and demand is growing with time due to the rapid population growth and aridity. The situation of the sewerage system in the cities is extremely critical, and there are no sewerage systems in the rural areas. There is an urgent need for substantial improvements and extensions to the sewerage systems treatment plants. Further development of water resources for agriculture and domestic use is one of the priorities to improve the agricultural yield of the country, and the domestic and industrial demands for water. This article discusses the overall problem and identifies possible solutions. Key words: Sudan, water resources development, community water supply, effective water-supply management, environment.

The influence of water and sewage networks on residential water consumption

Abstract: In this study a real case is used in order to evaluate the effect of the factors controlling the residential water demand in one of the suburb of the state of Kuwait. The study investigates the effect of having or not having water and sewage networks on the water demand. The importance of this study arises from the difference between the two studies residential areas in which one of them contains complete and modern water and sewage networks. The other area under investigation is adjacent to the first area but is lacking similar networks yet. These two residential areas have the same controlling factors for water demands, such as economical conditions, climatic conditions, standard of living, and social life. The method presented is based on a sensitivity analysis of the effect of networks availability on the per capita daily water demand. The analysis of data from both residential areas showed a greater water demands for area without networks, which is contradicting the expectations and experiences. Key words: water demand, residential water, sewage, network.

Need of benchmarking for socially and environmentally sustainable development of a major irrigation scheme

Abstract: It is a proven fact that the quantity and quality of available water resources have been recognized as limiting factors in development of most of the arid and semi arid regions. The function of the conveyance and distribution systems and services should be providing sufficient water in a timely manner so that it can be used efficiently for crop production. Reliability, flexibility and efficiency are the keywords for a modernization plan. Optimal use of available surface and groundwater, in any canal command area would result in their better utilization by maximizing the benefits from the crop production and the environmentally sustainable development and management of water resources in an integrated and participatory approach. Irrigation sector is the highest water consumer; therefore it is a sector where performance assessment is necessary to ensure optimum utilization of water. The major system deficiencies are low canal carrying capacity, over utilizations of water in rabi irrigation, flooding irrigation practices, low yield per unit irrigated area, low cost recovery in the Samrat Ashok Sagar irrigation project. This paper presents a need of benchmarking of major irrigation projects for socially and environmentally sustainable development in India based on integrated and participatory approach. Key words: Benchmarking, participatory approach, environmentally sustainable development, water management.