مجله آب و فاضلاب
پیاپی 51 (پاییز 1383)

Polycyclic aromatic hydrocarbons (PAHs) are the main pollutants in oil pollution. PAHs accumulation in aqueous phase causes some aquatic and human diseases Biodegradation methods of PAHs removal were studied using flasks and a reactor. Standard sampling was performed from polluted areas in Persian Gulf and samples were analyzed. COD, TOC, PAHs and heavy metals were determined. Results Showed that, Emam Hassan (EM), Deilam and Shaghab were most polluted areas (PAHs equals 9.8, 4.2, 2.7ppm respectively) and samples from the dept showed more pollution than from the surface. For the biological treatment, most active species of bacteria were isolated from the soil of the polluted stations. Most of them are among Pseudomonas, gram and catalazet+. Rotating biological contactor packed (RBCp) by providing high acclimation time for the microbial mass, found very suitable process for removal of PHAs. The pure bacterial culture from EM showed, 80% removal efficiency for naphthalene. As the biodegradation of PAHs take a long time, RBCp reactor was selected and the ability of mixed culture in removal of pollutants was studied. The bioreactor was run in two stages. The acclimatization stage took place in 30 days and evaluation of bioreactor in terms of effluent COD concentration and MLSS with initial COD influent of 600 mg/l was operated. COD and PAHs removal of 73 and 66 percent were found respectively while the influent COD was 1200 mg/l.

Stabilization ponds have high capability for treating the wastewater with high organic and hydraulic loading. Hence this system is a popular means of wastewater treatment for certain industries such as slaughterhouses, dairies and food processing plants. The main objective of this study was to investigate the efficiency of stabilization ponds for treating a high organic load wastewater receiving effluent from a slaughterhouse plant in Iran. The efficiency of Kermanshah slaughterhouse wastewater treatment plant was studied over six months from September 2000 to March 2001. The general conditions and operation of the plant were considered and some wastewater treatment indexes such as pH, TSS, BOD5, COD, coliform and fecal coliform in influent and effluent were determined.The quality of the plant effluent has significant difference with the standard limits recommended by Iranian Environmental Protection Agency. The average amounts of TSS, BOD5, COD, total and fecal coliform in effluent were 280.67 mg/l, 353.17 mg/l, 580.5mg/l, 1.51*107MPN/100ml and 2.10*105 MPN/100ml respectively. The results showed that the effluent could not be used for irrigation or discharged to surface water based on the recommended standard by Iranian Environmental Protection Agency. Also, the comparison of the average number of fecal coliform in effluent with the microbiological quality guideline of World Health Organization (WHO) showed that the effluent was not acceptable for use in unrestricted irrigation.

Municipal wastewater is one of the most important pollution sources for water supply resources. Soil, vegetable, and food material are exposed as well. Identification and enumeration of pathogenic agents particularly pathogenic Vibrios are beneficial for control and prevention planning of the infectious diseases. This research carried out to identify the distribution of the recognized pathogenic Vibrios emphasizing on identification of Vibrio cholerain the wastewater of city of Kermanshah in 2001. Population of city of Kermanshah was estimated over 713000 and produced wastewater was approximately 150 l/cap/d. The method of study was cross-sectional descriptive. Sampling procedure was adopted from standard Methods for the Examination of water and wastewater, and the method for Vibrios identification was according to finegold 1990. There were 8 discharge outlet domestic wastewaters, which had been chosen as sampling sites. Samples were collected weekly in randomized manner in day time. Although 288 samples should be collected statistically, 339 samples were collected and analyzed. The results indicated that site 7 with 5 positives, sites 4 and 8 with 3 positives, site 5 with 2 postitives and sites 2, 3 and 6 with one positive suspected to vibrio pathogens. However, not any Vibrio detected in site 1. The most positive samples were seen in spring, late summer and early autumn. The positive results were detected in May, June, September, and October. Among samples which have been detected as a positive could be likely Vibrio Parahemolyticus accourding to the differentiation tests. Vibro chloral was not found. It looks like the presence off vibrio parahemolyticus was due to wastewater discharged from sea food markets areas. So it has been suggested that this relationship could be considered through analytical study using PCR for detection of Vibrios.

The Gilarlo reservoir is one of the most important drinking water sources of Guermy city. However, because of undesirable water quality, have odor and taste problems in drinking water. Thus, it is necessary to monitor water quality in order to determine effective factors.Water quality assessment of the watershed showed that 56 and 0.47 tons of nitrates and phosphorus were discharged into the lake during 6 months of year respectively, and the main sources of pollutants were agricultural and domestic wastewater as well as geological factors. For water quality monitoring of the lake, 58 samples from the three vertical and longitudinal zones of the reservoir were collected. Then total and fecal coliform and dissolved oxygen, temperature, nitrites, nitrates, phosphorus, phytoplankton and zooplankton were analyzed. Studies showed that temperature stratification and eutrophycation process have occurred in the lake, and the situation has changed from meso eutrophycation during August to eutrophycation state during October, and this state was fixed during winter.

Every natural river has an capacity to assimilate wastes; this is referred to as the river's self purification capacity. DO content is usually an important water quality index. The water quality of a polluted river can be improved either by increasing the river's self purification capacity or by reducing the amount of waste loading the river receivers. Traditional physically based water quality models do not evaluate separately a receiving river's purification ability and the effect of waste loading; thus, these models are not ideal analytical tools for water quality management. This paper introduces and discusses an alternative river water quality modeling approach based on the linear systems theory. Steady-state-system response matrix is a means to summarize the interactions of loadings and responses for linear water quality models. BOD-DO variation in a receiving river has been investigated by following traditional physically based water quality models. A simple physically based river BOD-DO model was derived by Streeter and Phelps (1925) based on their Ohio River water pollution study. The Streeter-Phelps model has been used by sanitary/environmental engineers for many years to evaluate the waste assimilative capacity of a receiving river; it provides a basis on which the treatment requirement for wastewater discharged into the river can be determined. The BOD-DO variation in a time-variable river system with a dispersive effect is traditionally solved by numerical methods. In this study, physical parameterization method is used. Using this method, the system impulse response function of a receiving river can be determined by solving the governing equation of the corresponding physically based model with a Dirac delta function input. This modeling approach is an extension of Green's function techniques that solve a linear differential equation. In a linear systems model, a receiving river's patura-purification capacity is represented completely by the model's impulse response function, whereas the amount of waste loading the river receives is represented by the model's input function. The Enhanced Stream Water Quality Model (QUAL2E) is a comprehensive and versatile stream water quality model. In this paper a river was simulated with QUAL2E. Then a response matrix was built for determination of DO deficiency in any point of river.

The ground water resources have become the main source of drinking water for communities. High utilization of water has caused drastic reduction of ground water level. In order to maintain designed supply rate, either a new well need to be installed or the depth of programming optimal depth of well can be obtained so that the designed option, using the nonlinear maintained and total expensive to be reduced. In this study a nonlinear programming model was developed and is used to predict the optimal depth of existing well extension in fariman city pilot. In this research positive water balance for ultimate discharge rate is assumed.

Aquifer in alluvium of this plain is 520 km2. The aquifer is recharged from direct infiltration of precipitation and surface runoff, return flow from agricultural, industrial and domestic uses and groundwater input and discharged through water abstraction for different consumptions and groundwater output. The groundwater level hydrograph of shows that the level and storage of water continously decreased in the last years. In this research, times series model was used for forecasting groundwater level of plain in future. The groundwater levels in 1984-2003 were used as observed data. Then with time series model, the ARIMA(1,1,0) model was fitted and of groundwater level for next 20 years were forecasted. The results of forecasting model show that in the next 20 years the groundwater level will decreases by 17.5m. So, with limitation of water resources, drawdown of groundwater level and increase of water consumption in future, groundwater management in Hamedan-Bahar plain is essential for sustainable use of groundwater resources.

There are various methods for treatment and decolorization of industrial wastewater such as: chemical oxidation, biological treatment, electrochemical technologies, ion exchange, adsorption process, membrane process, chemical reduction, coagulation and flocculation Among these methods chemical coagulation and biological treatment are common methods of waste water treatment which are used as single or combined regarding the level of effluent pollution and also its characteristics. In this research, the performance of combined methods in decontamination of pulp mill effluent have been investigated. As a result combination of these methods is a suitable system for treatment of colored effluent discharged from pulp industries.

One of the important issues that have significant role in study of hydrology of basin is determination of lag time. Lag time has significant role in hydrological studies. Quantity of rainfall related lag time depends on several factors, such as permeability, vegetation cover, catchments slope, rainfall intensity, storm duration and type of rain. Determination of lag time is important parameter in many projects such as dam design and also water resource studies. Lag time of basin could be calculated using various methods. One of these methods is time series analysis of spectral density. The analysis is based on fouries series. The time series is approximated with Sinuous and Cosines functions. In this method harmonically significant quantities with individual frequencies are presented. Spectral density under multiple time series could be used to obtain basin lag time for annual runoff and short-term rainfall fluctuation. A long lag time could be due to snowmelt as well as melting ice due to rainfalls in freezing days. In this research the lag time of Jahanbin basin has been determined using spectral density method. The catchments is subjected to both rainfall and snowfall. For short term rainfall fluctuation with a return period 2, 3, 4 months, the lag times were found 0.18, 0.5 and 0.083 month, respectively.

This paper explains the importance of measuring the precipitation and water corrosivity in cooling water systems. The limitations of Raisner and Langlier indexes have been explained. Then the benfits of Puchorius index in determining the precipitation and water corrosivity have been investigated. Finally, as a case study, the limitations of Raisner and Langlier indexes against Puchorius index have been discussed for the cooling water system of hot rolling of Mobarake Steel Complex.

Disposal of raw municipal wastewater or effluent of preliminary treatment into the sea and ocean is economically more accepted and technically more efficient than secondary treatment. In this method, the wastewater disposed at the bottom of the sea in some points from diffuser. Nowadays, lots of researchers select outfall as a suitable alternative treatment method for coastal cities. The goal of this paper was to introduce the outfall as a wastewater treatment method and its design criteria considering different characteristics of the sea such as salinity, density, temperature, stratification etc. In addition, stagnant sea and thermal stratification is reviewed. In this paper the latest information were reviewed. In this alternative the wastewater treated under dilution, mixing and natural conditions. Moreover, sensitive coastal point are preserved from different wastewater pollutants. Usually, there is no limitation regarding discharge of coliform, DO, BOD, and nutrient concentrations in initial mixing zoom. The parameters such as thermal stratification, salinity stratification, density stratification, marine flows influence design of outfall.