WATER AND WASTEWATER
Year:2014 | Volume:25 | Issue:1 (89)|Papers Count:17

In recent decades, population increasing and its structural changings have doubled municipal water demand management importance and forecast. Proper planning and management is subject to the most important information about households. So, considering the physical and behavioural characteristics of consumers is necessary in different conditions. In this research, classifying influential characteristics and interaction of Neyshabour households in Razavi Khorasan on municipal water consumptions during different periods presented. Many influential parameters has considered in recent investigations then, Gamma Test abilities used for nearly all 27 variables, in a non-parametric space. Results showed that house age, landscape, cooler capacity, high-consumption appliances, number of connections, number of people in each connection, land area, commercial and residential arena, advantage of zone, booster pump, water pressure during the year and summer, maximum temperature, rainfall, average price of drinking water and one- lag consumption were the most important parameters affecting on two-months consumption. Yearly water consumption influenced by house age, landscape, seizin type, high-consumption appliance capacity, land area, residential area, booster pump, metering change, water pressure during the year and summer time, minimum and average temperature, and average price of drinking water. Despite previous studies, long run average consumption for consumers is sensitive to water pressure. However, consumer satisfaction about water and wastewater corporation services has affected their long run consumption. Therefore, qualitative and quantitative differences in influential affecting water consumption must devise in management policies for municipal water demand and supply.

In this paper a heuristic method with ad-hoc engineering concept is proposed for design optimization of integrated wastewater treatment and sanitary sewer network using ant colony optimization algorithm. The optimal design of integrated wastewater treatment and sewer network requires that the wastewater treatment location, layout and size of sewer network are optimally determined. The problem of finding the optimal design of integrated wastewater treatment and sanitary sewer network is an expensive task that should be formulated as an optimization problem if an optimal least cost design is required. This problem is a highly constrained Mixed-Integer Nonlinear Programming (MINLP) problem presenting a challenge even to conventional methods. In this paper an efficient heuristic method with ad-hoc engineering concept using ant colony optimization algorithm Is proposed and used to solve hypothetical test example and the results are presented and compared with those of obtained with using genetic algorithm. The results indicate the effectiveness and efficiency of the proposed method to optimally solve the problem of optimal design of integrated wastewater treatment and sewer network.

In this study a cell-based biosensor for measurement of BOD was designed and developed. Activated sludge collected from wastewater treatment plant of Shahinshahr was used as biological receptor and a Clark cell was used as transducer. According to the results obtained from the sensor calibration, a linear relationship between the current changes and glucose-glutamic acid (GAA) standard concentrations up to 50 mg/L was observed. The BOD values of different industrial wastewaters, inlet and outlet of treatment plant of Ardineh Company (Isfahan), and also inlet and outlet of domestic wastewater treatment plant of Shahinshahr, and outlet of treatment plant of Pegah Company (Isfahan) were measured using this biosensor. Comparison of the results of this biosensor and the results of the standard BOD test (BOD5) showed that the mean percentage error measured by the sensor was +29.6%. The results concerning the stability of the designed biosensor showed a stability time of 3 days for the response of biosensor.

Removing or decreasing hexavalent Chromium from wastewater to the permitted levels is important due to its non-biodegradation, bioaccumulation, cancer-causing and toxic effects. In this study, biosorption of Cr(VI) from aqueous solutions by Excess Active Municipal Sludge was investigated as a function of initial Chromium (VI) concentration (in the range of 5-90 mg/l), initial pH (in the range of 2-8), agitation speed (in the range of 50-200 rpm), adsorbent dosage (in the range of 2-10 g/l) and agitation time (in the range of 5-480 min) in a batch system. The optimum conditions were found by full factorial design approach. The results showed that the equilibrium time for adsorbent is 120 minutes. Also, sorption data have a good fitness by Freundlich isotherm model and adsorption kinetic is adopted with pseudo-second order model. In batch studies, at optimum condition (90 mg/l initial concentration, pH 2, agitation speed 200 rpm and adsorbent dosage 4 g/l), the adsorption performance was about 96%; the maximum adsorption capacity was calculated about 41.69 mg of Cr/g of adsorbent. Overall, it can be concluded that Excess Active Municipal Sludge, has a good performance as a biological, biodegradable, abundant and low-cost adsorbent for the removal of Cr (VI) from aqueous solutions.

Evaluation of the short-term fluctuations in water demand and consumption is one of the most important consideration in design and optimization of drinking water distribution networks. According to necessity of system ability to distribute water during peak demand conditions, the capacity and pipe sizing of network are determined based on multiplying Peak Factor in Average Daily Flow. It seems that Diurnal Demand Pattern through which Peak Factor is obtained, regionally varies due to many complicated reasons, mainly because of the number of subscribers. So, most of standards and references have recommended their own specific Daily Peak Factor, Hourly Peak Factor and Peak Factor with emphasis on localization of these terms. Considering the importance of regional studies on Peak Factors, this research was conducted for a group of rural networks in north-east part of Khuzestan Province, Iran. After installation of electro-magnetic flowmeter with maximum error of 0.3% and measurement of demand flow in 7.5-minute time intervals by data logger, during one-year period, Diurnal Demand Patterns and Peak Factors were determined. The considerable difference between Peak Factors resulted in this research and those recommended by national and some international standards or references, makes the importance of peak factor localization more and more obvious. For example, in the case of the smallest investigated network, the peak factor proposed by national standard 117-3 is 27.3% less than the actual factor acquired in present study. Also, the results show that calculation of peak factors without any notice on the negative effects of physical loss of unaccounted-for water can sensibly reduce peak factors 14.5% to 24.5% compared to reality.

The removal of zinc ions from aqueous solutions on the chitin extracted of shrimp shells has been studied by using batch adsorption method. Experiments were performed as a function of pH (3-7), metal concentration (50-500mg/l), and adsorbent dose (0 .5-10 g) at 25oC. .The equilibrium metal uptake was increased and percentage biosorption was decreased with an increase in the initial concentration. So, the data showed that optimum pH for efficient biosorption of zinc by chitin was 7. The pseudo first order and pseudo second order kinetic models were used to describe the kinetic data. The dynamic data fitted with the pseudo second order kinetic model for zinc. So, Experimental data obtained were tested with the adsorption models like Langmuir and Freundlich models and Biosorption isothermal data were well correspond by Freundlich model. So that chitin extracted of shrimp shells relatively high sorption capacity, when comparing with other sorbents that was evaluated as 270.270 mg/g.

The industrial revolution of the past century has resulted in significant damage to environmental resources such as air, water and soil. Petroleum contamination of soil is a serious problem throughout the oil producer countries. Remediation of petroleum contamination of soils is generally a slow and expensive process. Phytoremediation is a potentially less-damaging, cost-effective, but needs longer-term for remediation of contaminated land compared to the alternative methods. In this study the kinetics of petroleum hydrocarbon contaminated soils in Khozestan were investigated. For this paper Ryegrass (Lolium perenne) plant selected and the decline of total petroleum hydrocarbon (TPH) was analyzed after growth stage, every 10 days up to 90 days. The results of TPH concentration was fitted with zero-order kinetic, first-order kinetic and Higuchi model. The result indicated that degradation of TPH with presence of plants as a function of time was well fitted with the first-order kinetic model. The first-order rate constants (K) and half-lives (T1/2) for TPH degradation were 0.0098 1/day and 71 day; respectively. The results of phytoremediation showed that there were 65% decreases in TPH concentration with Ryegrass during the 17 weeks.

Nitrate is one of the contaminants in the aquatic environment and causes health problems. In the present study, removal of nitrate from aqueous solution using the mesoporous MCM-41 silica functionalized with diamine group (NH2-NH-MCM-41) was investigated. The modification of mesoporous MCM-41 materials by grafting diamine functional groups directly to the surface of a solid adsorbent was studied. The structure of the synthesis materials was characterized by XRD, BET and FT-IR. Results revealed that nitrate adsorption in batch system show high adsorption capacity (15.74 mg/g) and removal percentage (75%). The optimal pH, amount of adsorbent and initial concentration for removal of the nitrate anion on NH2-NH-MCM-41 were found at 7, 5 g/l and 110 mg/l, respectively. Maximum adsorption capacity was also attained at contact time 15 min for removal of nitrate anion. The experimental data were analyzed using the Langmuir and Freundlich isotherm models and the maximal equilibrium uptake capacity of 29.8 mg/g was obtained. The results of the present study showed that NH2-NH-MCM-41 adsorbent can be used as an adequate adsorbent for removing anion nitrate from aquatic environments.

This study was undertaken to evaluate the effectiveness of application of H2O2 and PAC in conjunction with electrochemical process in the removal of color from real textile wastewater. The experiments of electrochemical process were performed in the lab scale using copper electrodes. The influence of applied current (100- 400mA), pH (3-10), dosage of H2O2 (0.005- 0.02 M) and dosage of PAC (50- 200 mg/L) on decolorization and mineralization were evaluated. The optimum conditions were obtained at a pH of 3, with 0.01 M H2O2 and applied current 300mA for the electrolysis with H2O2 and pH of 7, 100 mg/L PAC and applied current 300mA for the electrolysis with PAC . The results displayed that electrochemical process in presence of H2O2 was more effective than PAC as an additive. The maximum of energy consumptions were 3.52 and 3.91 kWh/m3 for electrochemical process with H2O2 and PAC after 50min, respectively. Finally, it can be concluded that electrochemical process is an effective and reliable process for the removal of color and organic compounds from colored wastewater.

Different eucalypt species have various utilizations, therefore eucalypt species trials is essential for different ecological conditions. For this reason an eucalypt species and provenances trial was conducted at Yazd City Wastewater Treatment Plant, using industrial and domestic sewage under the randomizes complete blocks statistical design with four replicates and eight treatments at 3 x 3 m. spacing and 36 seedlings in each plot. The treatments consisted of: E. rubida (166-sh), E. saligna ig. botryoides (20762), E. saligna (171-sh), E. macarthurii (169-sh), E. viminalis (15211), E. sargentii, E. camaldulensis (41-zh), and E. microtheca. The results showed that after the first year of planting there were significant differences between the treatments (P<0.01) in respect to survival, height, diameter and crown parameters. The greatest survival after the first and second years of planting belonged to E. camaldulensis (41-zh), E. sargentii and E. microtheca (98.6%, 95.1%, 92.4% and 98.6%, 95.1%, 94.4%, respectively). The species E. camaldulensis (41-zh) had the best performance after the first and the second years of planting, although there was not significant difference between some of the eucalypt characteristics. Overall, the species E. camaldulensis (41-zh) can be recommended for forest plantation and wood production at sites similar to the trial condition, ecologically. The species E. rubida, E. saligna and E. viminalis are also recommended for plantation and wood production, using sewage irrigation, due to their fast growing performance, although they might have high mortality at their first stage of establishment. E. sargentii is a suitable species for desertification control due to its high resistance to soil and water salinity and somewhat coldness and its fast diameter and crown growth.

This paper has paid to review one of the structural flood control methods (levees). In order to speed up the design of levees, an optimization method has been proposed in this paper which can be a good alternative for the usual design methods. The advantage of using optimization method is that one can reach the optimal option by solving model for one time (or several times for further analysis) and there is no need to review various single options. Benefit-cost analysis has been used to optimize the dimensions of levee containing height of it and it's distance from the river bank. Obtained optimization model is a non-linear one that has been solved by LINGO 12 software. In this study, proposed system of flood control in dry Maali Abad river (TangeSorkh) of Shiraz has been studied. According to this studies and the execution of model, 20-year return period flood had the highest annual net benefit and was selected as the design flood. The obtained values for the height of levee and it's setback are respectively 1.7 and 6.1 meters.

General equations for predicting depth-averaged velocity in open channels are not well suited for trapezoidal open channels. In this study, an innovative method is developed for predicting the depth-averaged velocity distributions in smooth trapezoidal open channels with the best hydraulic section. Depth-averaged velocity was obtained using the boundary shear stress obtained in the present study. To calibrate the present analytical results, an experimental investigation was also performed. Analytical results compared well with the experimental data.

Water is one of the limited natural essential for sustainable development for developing countries such as Iran. To preserve water resources, it is essential to manage the consumption patterns. One of the imperatives of water demand management is to identify the effective factors on water consumption behavior. So, this paper studies water consumption behavior as an environmental behavior, and for this purpose, examines the relations of New Environmental Paradigm and water consumption attitude with water consumption behavior. Literature review showed that the data about domestic water consumption in Zanjan city is limited. So, survey method was chosen for this research. A questionnaire was distributed among 384 people (Zanjan’ dwellers) and the data was analyzed by SPSS software. The results indicated that there are relations between water consumption behavior with New Environmental Paradigm and water consumption attitude. Also, findings showed that demographic factors, such as age and income, have no effect on water consumption behavior. Finally, concerning the findings of the research, it is suggested to do future researches in qualitative method. Also, it is concluded that to make environmental friendly citizens, it is necessary to educate people.

The kinetic model of the pseudo-second order is a useful model for assessing the mechanism of the adsorption. This model is stated by linear and non-linear methods. The linear method is written by linear regression as four forms and non-linear method is done by trial and error method using Solver add-In in Microsoft Excel. The comparison and assessment of the correlation coefficient (r2) show the best accordance with kinetic model. In current work, the kinetic of pseudo-second order for the adsorption of Co (II) from aqueous solutions was studied by linear and non-linear methods. The results showed that the different values of the correlation coefficient were achieved for four forms. First type of the pseudo-second order kinetic (Ho model) showed the most value of the correlation coefficient. The results showed that non-linear method has the better accordance with experimental data than linear method.