WATER AND WASTEWATER
Year:2011 | Volume:23 | Issue:1 (81)|Papers Count:16

Direct discharges of municipal and industrial waste waters into water bodies through marine outfalls are considered as a common way to dispose the generated waste in coastal zones. Marine discharge, intensifying flow mixing and entrainment, decrease the concentration of polutant up to accepted concentration and meet the guideline values and to make possible continues discharge of flow into matine environment. During last years due to quick development of coastal desalination plants, surface discharge of preduced salty water into seas and oceans has increased significantly. In this study, releases of dense jets from surface rectangular channel into stagnant bodies are experimentally studied. The location of flow plunge point, impact point and discharge ultimate dilution were drown out by a digital video technology. In addition, using some conductivity probes located in ambient floor, waste filed dilution in flow impact point and discharge ultimate dilution were identified. Finally the obtained results were plotted and explained along with some diagrams to show flow nondimensional behavior. The results showed that the properties of flow are changing directly with ambient water depth and discharge initial fluxes.

The protection of river bank, especially in a channel bend, is important because it has been observed more scour in the outer bank of bend. The previous experimental studies were almost about scouring around the bank protection structures and less attention were paid to flow pattern around transverse structures in rivers. In this study the effect of relative radius of channel bend on flow behavior and flow pattern around a T-shaped spur dike located in section 45o of a 90 degree bend was investigated. Three relative radius of bend: R/B=2, 3 and 4 were studied. It was found that the flow pattern around a T-shaped spur dike is accompanied with two counter clockwise vortices at the upstream and downstream of the spur dike. Also increasing the relative radius of channel bend increases the length of separation zone, the upstream vortex and decreases the width of separation zone, the length of circulation zone and the downstream vortex.

Bottom racks is a hydraulic structure which is placed in the bed of stream through which, part of flow in the main channel is diverted. These structures have very wide application in industry, irrigation, drainage and etc. Of course much attention had been paid to the study of such structures, but characteristics of flow through bottom racks are complex. The present study was directed to estimate the discharge coefficient of a new kind of bottom racks including both transverse and longitudinal bars that named "mesh panel racks" without considering any solids in the fluid. This kind of bottom intake has advantages from structural point of view and has less deformation under static and dynamic loads. Laboratory setup with three mesh panel intakes was built and the effects of various parameters such as racks slope, porosity and geometry were explored. A dimensional analysis using Buckingham theory showed the effective hydraulic and geometric factors that affect the discharge coefficient (Cd) of bottom racks. Then, a statistical approach to determine the discharge coefficient of a rack structure was developed with linear and nonlinear regression using SPSS software. The efficiency of the proposed technique is high enough that the associated error is limited to 10%. Finally, hydraulic performance of mesh panel intakes was compared with regular type of bottom intakes, which consist of longitudinal bars. For this purpose, diverted discharge through both type of intakes calculated in same situation.

This paper investigates the application of a multi objective algorithm in the problem of multi objective design of water distribution networks. The problem is formulated using two different objective functions: minimizing cost and maximizing reliability. To measure the reliability, a new definition based on the original concept of fuzzy logic, named "Fuzzy Reliability Index" is introduced. Then, developing the Multi Objective Honey-Bee Mating Optimization algorithm based on it's single objective version, the multi criteria design of two benchmark networks is performed using predefined objective functions. The results obtained show that the proposed reliability index is able to provide desired reliability in the network. Furthermore, satisfactory results obtained by the algorithm in defining the pay off characteristic between total cost and reliability are shown. Finally, it is possible to use the developed model to introduce different and numerous non-dominant solutions to decision makers.

In urban catchment because of developed conditions, the amount of impervious area increases which tends to increase runoff volume, peak discharge rate and decrease of infiltration volume. Most of urban catchments are ungauged and runoff data does not exist, as a result, determining the hydrological response of urban catchments in consideration of complex drainage system is a necessity. For this purpose, storm water management models are considered as useful tools for planning and developing in urban areas. Analytical model is one of the storm water management tools which formulate the physical rainfall-runoff transformation. In this study, two analytical models are used to predict urban runoff volume. One of models predicts runoff volume on the basis of runoff coefficient and another is formulated in consideration of infiltration parameter. A test catchment located in Tehran city is selected for performing these models. Observed rainfall and runoff data are recorded in this catchment for comparing two approaches. Performance indicators such as Nash-Sutcliffe model efficiency coefficient, root mean square error (RMSE), coefficient of residual mass (CRM), absolute relative error and regression coefficient reveal the precision of two models for urban runoff prediction.

The purpose of this study was to cultivate three suitable emergent herbaceous species (reed (Phragmites australis), bamboo (Dracaena sanderiana), and umbrella plant (Cyperus alternifolius)) in laboratory scale using hydroponic method and to examine their potential in removing nitrate from contaminated water. Three containers with initial NO3--N concentration of 15, 20, 25 mg/L, one container of perfect omex fertilizer and the last one with plane water and soil were used in this study. The variations of nitrate concentration, its removal rate, and plant growth (dry and wet weight) were all measured during 8 months of the study. The experimental results indicated that reeds had higher ability to remove nitrate as compared to bamboo and umbrella plant. For the highest concentration, reeds, bamboo and umbrella plant absorbed about 95, 85 and 70 percent nitrate, respectively. There was a direct relation between dry weight and removal efficiency and the most amount of nitrate absorption was measured in root and rhizome of the plant.

The main purpose of this study is removal efficiency of Clinoptilolite (zeolite) in absorption of manganese in the two modes of single and compound element in solution. The zeolite used in this study was provided from Semnan mines with particle size of 350µm. The results showed that the optimum pH of both single and compound modes was 5. The kinetics data were analyzed by Lagergrn, Ho et al and Avrami models in the both modes (single and compound). It was found that the data can be expressed satisfactorily by Avrami model. The determination coefficient for Avrami model in both single and compound modes were 0.998 and 0.999 respectively. Also the average absorption rate for manganese in two modes were 0.242 mg/g. min and 0.0146 mg/g. min respectively. Langmuir, Frondlich, Sip's and Radlich-Patterson models were also used in this study.The results showed that Sip's model with determination coefficient of 0.998 and 0.993 and error of 0.0248 and 0.0166 for both single and compound modes respectively, was more reliable for expressing the data than others.The Manganese absorption capacity for single and compound modes were 3.67 mg/g and 2.63 mg/g respectively.The surface area of Zeolite was measured using the methylene blue absorption method and was found 12.31 m2/g.

Biological methods of metal removal from aqueous solutions, defined as bio sorption, have been recommended as cheaper and more effective techniques. Bio sorption of lead by dead Mucor indicus biomass treated with NaOH was studied over a range of pH. The pH plays an important role on bio sorption. Low pH resulted in a decrease in the bio sorption capacity. At pH 3.0 or higher, the bio sorption of lead ions increased sharply. Under these conditions, optimal pH=5.5 was obtained. The Ho's pseudo-second-order model described the bio sorption kinetics, and the equilibrium data could be fitted by Langmuir isotherm equation. The pH values were increased at the end of reaction procedure.

Since the semi-arid and dry, access to good water quality is associated with restriction, so exploitation of sewage effluent for irrigation is very important. Nowadays, use of natural materials in water purification and sewage is increasing. One of these materials are seeds of Moringa Peregrina plant. In this research the performance of Alum and Poly Aluminum Chloride (PAC) were compared with Moringa Peregrina seeds powder in wastewater treatment. The samples of sewage were collected from fluvial that received domestic sewage and used without any pre-treatments. Sewage samples in separate stages were contacted with different concentrations of Moringa Peregrina seeds powder, Alum and Poly Aluminum Chlorides. In these experiments the concentration changes of nitrate, phosphate, turbidity, TDS, electrical conductivity and pH is studied. Results showed that the use of Alum and PAC increased the electrical conductivity and sometimes increased the residual salts. Also the results showed that the highest removal efficiency of phosphate and nitrate are related to Moringa Peregrina, so that 120 mg/lit Moringa Peregrina able to reduce 80 percent of phosphate and 110 mg/lit of Peregrina, reduce 50 percent of nitrate. The results indicated that the use of Moringa Peregrina seeds powder reduced the sedimentation time from 30 to 10 minutes and dewatering of sludge produced was better than the others.

The use of industrial wastewater for irrigating farmlands is currently increasing, especially in arid and semi-arid areas because of water shortage for agriculture. The use of industrial wastewater in farmlands could help the sustainable soil fertility through improving the physical, chemical and biological soil characteristics. On the other hand, wastewater may contain toxic elements that are detrimental to soil microorganism and biochemical reactions. The aim of this study was to determine the effects of industrial wastewater either treated or untreated on soil enzyme activities. The wastewater samples were taken from Zobahan and Isfahan Foolad Mobarakeh steel plants and Polyacril plant. Soil samples were moistened at 70% field capacity using wastewaters and then placed at 25oC for 3months in an incubator. Soil samples were analyzed to examine enzyme activities at monthly intervals. Results showed that during the first two months of incubation enzyme activities increased inwastewater-treated soils whereas a reverse trend was seen in the third month. In general, industrial wastewaters caused a 30% decrease in the average activity of arylsulfatase, however, it increased the average activity of alkaline phosphatase, urease and saccharase by 7.5%, 60% and 26.5%, respectively. Overall, regardless of the incubation period and sampling time, adding wastewater to the soil increased enzyme activities. The presence of carbon and nutrients in wastewater could lead to an increase in microbial activities and populations, resulted in increasing synthesis and production of enzymes involved.

In order to investigate the effect of Sewage Sludge (SS) application on the amount of micro elements in soil and absorption of these elements in plant organs of medicinal plant borage (Borago Officinal is), an experiment was carried out in split plot based on complete randomized block design in three replications in the field of the University of Agricultural of Sari. fertilizer treatments were two leves 20 and 40 tons per hectare of sewage sludge, mix SS and fertilizer, fertilizer and control and years of consumption were inclusive: (1385), (1385 and 1387), (1385 and 1386), (1385, 1386, 1388), (1385, 1386 and 1387) and (1385, 1386, 1387 and 1388). The results of the study showed that fertilizer treatments, on the amount of absorbent micro-elements in the soil, leaves and petal of plant were significant. The years of fertilzer consumption on the all of the cases except amount of Zn and Mn absorbent in leaves of plant had a significantly effect. The interaction between years of consumption of fertilizers and fertilizer treatments on concentration of all of micro-element except Mn in the soil were significant, in the leaves had a significantly effect on the amount of Fe and Cu absorbent only and in the petal showed significant effect on the amount of Mn and Cu absorbent.

This research work was carried out in lab scale using a Jar-test set up. In order to compare the performance of four inorganic coagulants (poly aluminum chloride, ferro sulfate, ferric chloride, aluminum sulfate) in removal of turbidity and color from water, three independent variables (turbidity, color and coagulants dosage) were investigated. The region of exploration for the process was taken as the area enclosed by turbidity (10, 20, 50 NTU), color (5, 10 TCU) and concentration of coagulants (5, 10, 15, 120, 25, 30 mg/l) boundaries. The rapid and slow mixing steps were provided by the rate of 80 rpm for 1 min and 30 rpm for 20 min, respectively. The samples were then remained for 30 min as settling stage. Four parameters including turbidity, electrical conductivity (EC), pH and color were measured from the samples supernatant. Settling characteristics of the flocs formed were descriptively reported as poor, fair, good and excellent. From the results, poly aluminum chloride with concentration of 5 mg/l was found to be the best for the removal of turbidity (99-99.8 %) and color (100 %). However, fine flocs with very good settling velocity was observed at the condition with initial turbidity of 10, 20, 50 NTU. Increase in EC along with decrease in alkalinity was obtained as the coagulants concentrations were increased. The maximum and minimum amount of increase in EC and TDS were resulted from ferric chloride and poly aluminum chloride, respectively.

Targets: Pollution of water resources by pesticides is one of the environmental problems because application of such these pesticides is increased by development of agriculture and variety of plant pests. As there are too many agricultural lands, farms and orchards in Shemiranat which are sprayed by poisons periodically and because drinking water of people is provided by ground waters, there is the probability of leaking of poisons to water wells. So pesticides can be a serious threat for drinking water resources of the region. Study Methods: This research is a descriptive study based on sectional analysis method. In this research 12 samples of water are collected from 3 drinking groundwater preparation stations in Shemiranat during 4 seasons of 2009-2010. The samples are analyzed by GC/MS mechanism and by chromatography gas method to measure the rest of organophosphate pesticides and by GC/ECD mechanism and by chromatography gas method to measure the rest of chloro-organic pesticides.Results: According to analysis of phosphate pesticides in three water wells of Hanzak, Anbaj and Kand-Sofla, no phosphorus organic pesticide was seen in samples of water for all seasons, but according to analysis of chloro-organic pesticides in these three water wells, some amounts of pesticides were found in condensed water of all three wells especially in the samples of June. It should be mentioned thatthe amount of pesticides in samples of water are less than authorizes level according to 1053 National Standard principle. The pesticide in condensed samples of water indicates leakage of poisons into the drinking water resources of the region and is an alert of more pollution in future.