a. r. mesdaghinia

Environmental burden of disease (EBD) studies are one of the most important needs for determining the current situation, increasing the effectiveness of health policies and programs and prioritizing environmental health interventions. This review article was evaluated the status of the EBD in Iran based on the results of the latest Global Burden of Disease (GBD) Study, other international studies and national estimates in the country. In this study, the researches on the EBD in Iran were identified by searching in the international and national scientific databases and the search results were studied and analyzed. The review of the EBD studies showed that based on the results of the GBD study, the share of environmental risk factors in the total burden of diseases in the country in 2017 according to the disability-adjusted life years (DALYs) and deaths were about 8 and 13%, respectively. According to the results of the GBD study, the contributions of environmental risk factors in the attributable DALYs in the country in 2017 (a total value of 1,648,329) were as follows: ambient air PM2.5 for 45.0%, occupational risk factors for 25.1%, exposure to lead for 19.4%, unsafe water source for 5.0%, tropospheric ozone for 1.7%, lack of access to handwashing facility for 1.5%, unsafe sanitation for 1.4%, residential radon for 0.6%, and household air pollution from solid fuels for 0.3%. The total DALY rate and death rate attributable to solar ultraviolet radiation in Iran in 2000 were estimated to be 46.2 and 0.7, respectively. The DALY and the DALY rate attributable to elevated levels of fluoride in drinking water due to dental fluorosis in the country in 2017 were 3,443 and 4.14, respectively. The evaluation of the effect of water fluoridation as an environmental protective factor showed that the intervention by reducing the risk of dental caries could fall the DALY and DALY rates in the country by 14,971 and 18.73, respectively. In the period of 2005-2017, the DALY rate (per 100,000 people) attributable to ambient air PM2.5, tropospheric ozone, residential radon, and occupational risk factors rose that the result increases the importance of the preventive measures and controls of these risk factors. There was a considerable difference in the burden of disease attributed to each risk factor in various international studies as well as between national and international studies. The results of national studies on the burden of diseases attributable to environmental risk factors are considered to be more reliable and practical due to the application of more detailed data and conducting subnational evaluations; therefore, the strengthening and continuing these studies at the national and sub-national levels with regard to priorities, needs, and spatiotemporal trends using domestic reliable data and information are necessary and strictly recommended.

Radon is a radioactive, odorless gas. Radon gas with the emission of alpha radiation and sticking to aerosols in the air can cause lung cancer. This study evaluated the concentration of radon in residential houses and public places in Firuzkuh city and compared the values with the recommended international guidelines. Radon gas concentration was measured by passive measurements using CR-39 detectors. The detectors were placed in houses and schools of the city for three months. After this time, the detectors were located and placed in a 6.25% normal solution at 85 °C for 4 hours in a laboratory. After preparation, using an automatic scan and appropriate statistical method, the concentration of radon gas was determined. The results indicated that the average concentrations of radon gas in homes and public places were 137.74 and 110.17 Bq/m3, respectively. Comparing the results with the WHO guideline showed that 76.3% of the homes and 66.7% of the sites had a concentration above the guideline (100 Bq/m3). The results of this study can be used to prepare the National Radon gas map in the country.

Antibiotics are a group of emerging contaminants in the aquatic environment. Antibiotic residues threaten the human health and ecosystem in the low concentrations found in the environment. Hence, the present work has been conducted to investigate the occurrence and removal efficiency of most prescribed antibiotics including amoxicillin, penicillin, cefixime, cephalexin, ciprofloxacin, erythromycin and azithromycin detected in two urban wastewater treatment plants (WWTPs) in Tehran. The present work is an applied research based on USEPA method no. 1694, to investigate pharmaceuticals residues in water by HPLC/MS/MS in year 2016. The differences between target antibiotics residues were investigated statistically. After the calculation of the removal efficiencies, the normality of the data was assessed. Then, parametric and non-parametric tests were used to compare the removal efficiencies in both WWTPs. There was not a significant difference between the influent and effluent concentrations of cefixime and azithromycin (in Ekbatan WWTP) and cefixime (in southern Tehran WWTP). There is a significant difference between the removal efficiencies of cephalexin (p=0.005) and erythromycin (p=0.002) in two WWTPs. The Highest median removal efficiencies were observed for cephalexin 94.41 and 99.47 in Ekbatan WWTP and southern Tehran WWTP, respectively. In addition to the type of treatment processes, it is physicochemical properties of the selected compound has a significant influence on removal efficiencies.

Supply of safe drinking water to each community is one of the most important challenges in improving the general community’s health. Considering the importance of the research on water quality, identification of water quality research gaps was performed by reviewing the relevant studies through a systematic review for Iran.
In this study 638, 166, 300 and 1000 relevant articles were found on Scopus, SID, Magiran and Iranmedex databases, respectively. Out of 2104 articles, 1394 articles were excluded from the study. Finally, 710 articles were further reviewed.
Monitoring of pollutants by a descriptive study was the main objective of the most studies (36.62%). Around 13% of the studies were performed on a laboratory scale. Organic pollutants in Iran have been concerned only in 17 provinces, and other provinces have not participated in this regard. Nitrate is studied in around one fifth of the total studies. Heavy metals were also considered as a parameter of concern in the studies carried out on monitoring drinking water resource quality.
This study reflects the research gaps and provides a basis for prioritizing water quality research in Iran. More actions and sound planning should be taken to monitor organic and inorganic pollutants. Chemical and microbial risk assessment, tracing the fate of pollutants and assessment of their ecological effects, investigations on advanced water purification processes, the use of bioremediation methods, identification of biological contaminant using biomarkers and molecular identification techniques are the most important research priorities that require more investigations.

Water corrosion and scaling are known as destructive phenomenon of drinking water quality and water facilities. In this study, the groundwater tendency to corrosion or scaling in source water, water storage reservoirs and distribution system were studied. Simultaneous use of some qualitative and a quantitative index along with statistical analyses to assess the water scaling or corrosion tendency were investigated.
The data analysis of groundwater, water storage reservoirs and water distribution system in rural area of Kurdistan province were analyzed and the amount of Langelier (LI), Ryznar (RY), Pockorius (PSI) and Larson–Skold (LS) and CCPP indices were determined. Corrosion and scaling threshold for qualitative indices were determined based on CCPP index. The mean of indices was compared with the thresholds using independent t-test. ANOVA was used to assess the difference between the indices in different sources of water.
The balance range for LI, RY and PSI found to be -0.1-0.05, 7-9 and 7.1-8.5. The mean CCPP for groundwater, reservoirs and networks were 9.27 ± 1.29, 9.13 ± 1.25, 11.25 ± 1.23, respectively. All three sources of water have some tendencies toward scaling; however, a significant balance status was confirmed statistically. According to Larson–Skold index, sulfate and chloride anions did not play a role in scaling process.
The use of qualitative indices with CCPP index can provide more accurate estimation of water tendency toward scaling or corrosion. The assessment of qualitative indices along with CCPP is recommended in drinking water corrosion monitoring studies.

Exposure to chemicals such as heavy metals can be occurred through the route of drinking water consumption. Chromium is an important pollutant because of its role in the appearance of carcinogenic and non-carcinogenic health effects in humans. In this study, we studied the carcinogenic risk and non-carcinogenic hazard of chromium due to the consumption of bottled drinking water distributed throughout Iran.
The Hazard Quotient (HQ) and Excess Lifetime Cancer Risk (ELCR) indices were calculated. Monte-Carlo simulation technique was adopted for simulating uncertainty in the estimation of HQ and ELCR based on the input variables namely the concentration of pollutant, per capita water consumption, body weight, reference dose, biological availability, and source contribution factors.
The average concentration of chromium in bottled waters determined was 4.79 ± 2.32 µg/L. The amounts of HQ and ELCR for the age groups of lower than 2, 2 to 6, 6 to 16 and over 16 years old were 0.000354, 0.00292, 0.00236, 0.00147 and 4.04×10-11, 5.99×10-10, 8.61×10-10 and 2.34×10-9, respectively.
In regard to the concentration of chromium in bottled waters in Iran, the incidence probability and the possibility of carcinogenic and non-carcinogenic effects by this pollutant due to the consumption of bottled water are considerably low and there is no health concern for any age groups.

Compost is beneficial for conditioning the structure and nutrient content of soil. Toxic metals are the most important contaminants that can enter the food chain through the compost products and affect human health. The aim of this study was to assess the arsenic, mercury, cadmium, and lead levels in six brands of vermicompost produced from the organic solid wastes in Tehran and to compare the amounts with the international and national standard levels.
This was a descriptive - analytical study in which samples of six brands of vermicompost products were randomly selected from the distribution centers in Tehran, and from each brand four samples were prepared (24 samples). Then the samples were extracted using the TCLP (Toxicity Characteristic Leaching Procedure) method and after filtration the metal concentrations were measured by Inductively Coupled Plasma (ICP). All data were analyzed using Excel software.
The means and standard deviations of the toxic metals concentrations (arsenic, mercury, cadmium, and lead) in the collected samples of each brand were reported in terms of mg/kg. The maximum concentrations of these toxic metals were 7.45, 0.15, 0.19, and 79.95 mg/kg, respectively.
The results indicated that the levels of toxic metals in the vermicompost samples derived from the municipal solid waste in Tehran were lower than the permissible limits of the national and international standards.

Heavy metals are regarded as toxic stable elements in the environment that with the entry into water sources, finally it enters into the biological cycle of life and develops some adverse effects. Therefore, the present study aimed to determine the concentration of chromium and arsenic heavy metals in the river basins of Baft and Ravar dams.
This descriptive cross-sectional study was conducted from August 2013 to June 2014. During the field surveys of the river basins, 4 sampling stations of river basins of Baft and Rabor dams were selected. One combined sample was taken on 15th of each month from the mentioned river basins as well as Baft and Rabor dams. The chromium and arsenic concentrations were measured for 12 months in river basins of Baft and Rabar dams by Furnace Atomic Absorption device, and the study data were analyzed applying SPSS software.
The mean concentration of chromium was reported 5.01 and 5.19 in the river basins of Baft dam and 5.44, 5.5, 5.42 and 5.45 ppb in river basins of Rabor dam. The mean concentration of arsenic in the river basins was demonstrated to be 16.52 and 11.71 ppb in Baft dam, and 12.28, 13.6, 7.13 and 8.78 ppb in Rabor dam. In addition, the mean concentration of chromium was reported 5.02 and 5.38, and arsenic concentration was obtained 23.53 and 9.12 ppb, respectively in Baft and Rabar dams.
Based on the study results, the chromium concentration in the studied stations was demonstrated to be significantly less than guidelines of WHO, EPA and Institute of Standards and Industrial Research of Iran, whereas arsenic concentration was demonstrated to be significantly higher compared to these guidelines(p

A new biological domestic wastewater treatment process, which has been presented these days in activated sludge modification, is Upflow Sludge Blanket Filtration (USBF). This process is aerobic and acts by using a sludge blanket in the separator of sedimentation tank. All biological flocs and suspended solids, which are presented in the aeration basin, pas through this blanket. The performance of a single stage USBF process for treatment of domestic wastewater was studied in laboratory scale. The pilot of USBF has been made from fiberglass and the main electromechanical equipments consisted of an air com pressor, a mixing device and two pumps for sludge return and wastewater injection. The wastewater samples used for the experiments were prepared synthetically to have qualitative characteristics similar to a typical domestic wastewater (COD= 277 mg/l, BOD5= 250 mg/l and TSS= 1 mg/l). On the average, the treatment system was capable to remove 82.2% of the BOD5 and 85.7% of COD in 6 h hydraulic re tention time (HRT). At 2 h HRT BOD and COD removal efficiencies dramatically reduced to 50% and 46.5%, respectively. Even by increasing the concentrations of pollutants to as high as 50%, the removal rates of all pollutants were re mained similar to the HRT of 6 h.

The goal was to upgrade and/or uprate the traditional non-contact array by producing few modifications in the configuration of this model in order to maximize light receiving of water from the UV lamp and a better disinfection. An innovative non-contact model was made with a design based on irradiation of water, which was flowing as two thin waterfalls around a UV lamp in order to have direct germicidal rays from all positions of the lamp. By this water cir culating and traditional water flow in an ordinary canal below the lamp, UV light would reach every drop of water effec tively. Another model which had been studied was a simple stair type design in which a bare lamp was fixed over the shiny steel steps. Re sults of water disinfection in two flow rates of 12 and 24 L/min were compared with traditional design at ex actly similar conditions. Disinfection in this new model produced more reduction in fecal coliforms concentration than the traditional array and the inactivation efficiency was specified to be 3.65 log reduction compared to 2.93 log, in the turbidity of 0.5 NTU. Be sides, this new model was quite capable in disinfection of water with high turbidities up to 20 NTU. The reduction in disinfection efficiency at higher flow rates for new model was much less than traditional ar ray. Results of water disinfection in the simple stair type were not wonderful and even it was less satisfactory compared to tradi tional model. The reason is that the flow of water was not set parallel to the length of the lamp.

Mosquitoes transmit several diseases to human. There are several measures for control of larvae. As part of Integrated Vector Management (IVM) program, the utility of floating layers of polystyrene beads (EPS) is a po­ten­tial alternative in habitats of mosquito larva. EPS beads prevent oviposition of mosquito as well as killing the im­ma­ture stages by forming a tick layer on the water surface. They are cheap, environmentally safe and do not need fre­quent application and remain on the surface of water for long time. The objective of the current study was to asses the effectiveness of two types of polystyrene beads of (EPS) and (SWAP) for control of mosquito larvae under labo­ra­tory conditions. Anopheles stephensi and Culex quinquefasciatus were used for experimental purposes. In each tray 250 lar­vae of late 3rd and early 4th instars were introduced. The experiment was conducted on 4 replicates for An. ste­phensi, Cu. quinquefasciatus and combination of both. Emerging of adult mosquitoes were calculated every day until the end of experiments. Mortality rate and Inhibition of Emerge (IE) for Cu. quinquefasciatus, An. stephensi and combination of both spe­cies was 97.8%, 100% and 99.07%, respectively using EPS. In average, EPS was able to kill 98.9% of lar­vae. The fig­ures with SWAP were 63%, 91.05% and 72.65%, respectively. The average mortality for mosquitoes was 75.57% EPS and SWAP beads can be very effective and practical for elimination of An. stephensi and Cx. quinquefas­ciatus under the laboratory conditions.

Hospitals generate relatively large quantities of wastewater that may contain various potentially hazardous ma terials; therefore the proper management of hospital wastewater is essential. In this cross-sectional study, the quality and quantity of wastewater in the hospitals of Tehran University of Medi cal Sciences (TUMS), Tehran, Iran, were studied and the suitable method for wastewater management in the hospitals was determined. Monitoring of pH, TSS, BOD5, COD and total coliforms indicated that the quality of wastewater in the hospitals was similar to domestic wastewater. The wastewater production in the hospitals was determined to be in the range of 398 to 1090 L/d/(occupied bed). The study on wastewater treatment and disposal methods demonstrated that discharge to munici pal wastewater collection system is the best alternative for wastewater management in the hospitals, but this approach is not ap plicable for all of the hospitals. Baharloo, Cancer Institute, Children, Farabi, Imam Khomeini, Razi, Roozbeh, Shariati and Valiasr hospitals can be connected to municipal wastewater collection system at present. It is recommended that these hospitals’ wastewater be discharged to municipal wastewater collection system. Amir Alam, Bahrami, Mirza Koochak Khan and Sina hospitals will be able to discharge their wastewater into sewerage net work at second phase of Tehran sewerage project (in 2010) and Arash Hospital will be able to discharge its wastewater into sew erage network at third phase of Tehran sewerage project (in 2015). These hospitals have to select onsite separate waste water treatment alternative.

Discharge of Wastewater of Cleaning Industries to environment with special physicochemical characteristics has negative effects and in the other hand is not easily biodegradable because in these wastewaters ratio BOD5/COD is low and therefore biological treatment of them is difficult. Nowadays best method for degradation of Wastewater is advance oxidation processes. In this study investigated efficiency of Fenton process in remove anionic detergent and COD and improved from ratio of BOD5/COD.

This investigating is descriptive- empirical study that paksan factory was local sampling of wastewater. 30 wastewater composite sample24hr were taken during study period and then chemical characterization was performed by determining the following parameters: (COD, BOD, MBAS, PH, T) Then Sample of row wastewater were prepared and used in the experiments for determining the efficiency of Fenton process in treatment. Treatment experiments performed by use of various concentrations of H2O2 and ferrous iron at constant pH of 3and temperature of 25 in a jar test apparatus adjusted at 200 rpm and for contact time 60 min. Fe+2 on removal (COD, MBAS & BOD) applied ANOVA. and after that for analysis of effect H2O2

The results of analyze showed that the concentrations of COD, ranging from 6254-13040 mg/l and concentration of BOD was 2590-3200mg/l and concentrations of MBAS were 245-1120 mg/l and results showed that the BOD5/COD ratio was 0.34±0.09. At constant pH of 3 and temperature of 25 for contact time 60 min, about 40% of MBAS with first concentration 470 mg/l removed by H2o2 with concentration1800and fe+2 with concentration 340 mg/l. concentration of COD reduced from 8750 to 5998 mg/l, and the ratio of BOD5/COD improved from 0.334 to 0.340.

Wastewater from this industry has quality characteristics with deferent ranging and high organic load and because of high concentration of foaming that prohibit of oxygen infiltration in wastewater and nonbiodgredable material. These wastewaters are not easily subjected to conversation system of biological treatment; therefore suitable method for treatment of this wastewater should reduce organic load foaming and improve ratio of BOD5/COD advance oxidation process is one method with good efficiency for treatment of this wastewater.

Abstract: Although stabilization ponds and lagoons are suitable treatment processes due to simplicity of operation and low per capital costs, the effluents of these systems have too high of a total suspended solids concentration to be discharged into receiving waters. This problem is mainly caused by algae. In this study, an electro-coagulation reactor was examined to re­move algae from the final effluent of the wastewater treatment plant belong to Bu-Ali Industrial Estates (Hamadan City). For the continuous flow electro-coagulation reactor used in these experiments three aluminum anodes were util­ized. This type of metal was selected because it could introduce the flocculation agent into the effluent, thereby algae could be removed by both mechanisms of electro-flotation and electro-flocculation. The results of treatment were remarkably good and the efficiencies of total suspended solids (TSS) and chlorophyll a removal reached to as high as 99.5% and about 100% by applying a power input of about 550 W. In fact, this level of power input was needed for complete removal of algae in a low retention time of 15 minutes. Meanwhile, by applying less power input of about 100Wdm-3, the required time for a relatively same treatment was reached to 30 minutes. It is expected that this method which is also known as a multiple contaminants removal process will be consid­ered as a suitable alternative for final polishing of effluents from lagoons and similar treatment systems.

Abstract: Irradiation of water by UV has been considered as an attractive alternative for disinfection because its low- im pact, pathogen killing capacity shows tremendous promise for meeting today’s drinking water regulatory requirements. This study has been performed with the objective of utilizing medium pressure lamp in the preliminary stage of municipal wa ter treatment, namely prior to water clarification and filtration. Raw water samples were irradiated for 30 s in a lab-scale closed reactor. Disinfection results showed nearly 2 log reduc tion in HPC for all the samples without formation of nitrite in excess of its MCL. As in a few previous works the forma tion of nitrite as an objectionable DBP had been reported, this study was extended by preparing synthetic water sam ples having different amounts of nitrate and turbidities. As far as the initial nitrate concentration dose not exceed 10 mg/L N-NO3, there would be no risk of nitrite increas ing in excess of the MCL. Meeting the goal of at least 90 % disinfection for water samples with turbidity levels of as high as 750 NTU is possi ble by utilizing medium- pressure UV lamp.

Exposure to inorganic arsenic mainly occurs via drinking water, however because of potential changing of water sources during time, there is not consensus over the best route for assessment of past exposures to arsenic. At present study, we compared three potential sources of data in this regard. Thirty nine human hair samples were taken from persons residing in three villages of Bijar city in Kurdistan province of Iran with different drinking water sources and different levels of arsenic. All the subjects were female and at least one gram of scalp hair was gathered from the distal part of participants’ hair. Samples were analyzed using Neutron Activation Analysis method. Arsenic concentration of water samples were measured using Silver Diethyl Ditiocarbomate Method (SDDC) and the total intake of arsenic through drinking water were calculated for each participant. According to results, arsenic content of drinking water ranged from 0 to 0.455 mg/l (average: 0.18). The figures for arsenic concentration in hair were from 0.012 to 3.41 mg/kg (average: of 0.53) and for calculated total intake from 0 to 8.9g (average: 2.02). A close relationship between calculated total intake via drinking water and arsenic concentration in hair (R=0.711, P<0.001) was obtained and also relationship between current arsenic content of drinking water and arsenic concentration in hair (R= 0.662, p<0.001). Using age as a covaiate did not alter the results.

Consumption of water contaminated with arsenic can cause different adverse health effects in humans. Therefore measurement of arsenic concentration in drinking water resources is necessary before implementation of any water supply projects and during operation and also for determination of any treatment processes efficiency.In this research we aimed to determine arsenic content of drinking water resources of some villages in Bijar city of Kurdistan province.  

For this purpose accuracy and precision of two field (Ez arsenic test kit) and laboratory silver diethyldithiocarbamate spectrophotometric method (SDDC) for measurement of arsenic in water was studied. Accuracy and precision of both methods was determined through analysis of synthetic distilled water containing specific concentration of arsenic. Then 44 villages was monitored and samples of polluted water was analyzed using SDDC.  

The results showed that both studied (field and laboratory) methods have high precision and accuracy for measurement of arsenic in drinking water. In the case of kit it is necessary to use 9.6 ml as sample volume. The field monitoring of 44 villages of Bijar showed that drinking water of 5 villages has high level of arsenic considering national drinking water standard for arsenic (50µg/L). The highest level of arsenic was observed in Gavandak equal to 422.5µg/L (8 times of national standard and 42 times of WHO guideline).  

Considering the widespread location of water sources in our country, it is recommended that Ez arsenic test kit could be used in the wide range of field monitoring activities. For accurate evaluations, SDDC method is preferred at reference laboratories considering advantages of mthod e.g speciation definition and independency to advanced instruments.

Abstract: Cryptosporidiosis is a gastroenteric disease caused by the protozoan parasite Cryptosporidium parvum. Water–borne transmission of this organism has become more prevalent in recent years. Current method for detection of C. parvum oocysts in water is immunofluoresence assay (IFA). The method is time consuming, laborious and particularly not–specific. It cannot determine the infectivity of detected oocysts. We have evaluated a nested- PCR assay for sensitive detection of C. parvum oocysts in water samples. Water sample concentrates were spiked with Cryptosporidium oocysts and after DNA extraction and purification by QIAamp DNA mini kit, detection was achieved by nested PCR amplification of a 200 bp region of hsp70 gene specific for C. Parvum. The method could detect as few as one oocyst in seeded tap water samples. On the basis of these results, PCR could be a useful tool in the monitoring of water samples for the detection of Cryptosporidium oocysts.

In this research, the Chloroform (CHCl3) removal effectiveness of two water treatment systems including membrane technology and granular activated carbon (GAC) adsorption were studied. Two bench-scales were designed and set up: 1) Nanofiltration (NF) spiral-wound modules and 2) GAC adsorption column. Chloroform was considered as trihalomethanes (THMs) basic indicator compound. The inlet and outlet CHCl3 concentrations were detected by gas chromatography (GC) with electron capture detector (ECD). The study was carried out for the two cases of spiked deionized water with CHCl3 and chlorinated Tehran tap water. Flow rate, CHCl3 and total dissolved solids (TDS) concentrations were considered in both treatment systems and the transmembrane pressures for membrane pilot, as the basic variables affecting removal efficiencies. Results showed that CHCl3 rejection coefficients for NF 300 Da, NF 600 Da and GAC Column, with various operation conditions had a range of 55.2% to 87.8%, 78% to 85% and 41.4% to 74.1%, respectively. It was found that removal efficiencies for NF 600 Da were lower than those of NF 300 Da and GAC column. The obtained data were analyzed by SPSS and non-parametric Kruskal-Wallis method. Results showed a positive correlation between the flow rate, CHCl3 concentration and chloroform rejection coefficients and the TDS concentration had no significant effect on chloroform removal efficiencies.

طSludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly handled and disposed, it may produce extensive health hazards. On the other hand, this sludge has benefits for plants and soils. Thereupon, land application of sludge has received much attention over the traditional incineration and dump in sea. The comprehensive regulations of U. S. EPA title 40 CFR parts 503 include criteria and standards for land application of sludge. One of the most important wastewater treatment plants in Tehran, Iran is Shoosh Plant, which applies its waste sludge in agricultural lands after dewatering in drying beds. In this research, waste sludge from drying beds was examined according to 40 CFR parts 503. Results indicate that the dehydrated sludge has not the characteristics required for final discharge. If the dewatering process in the existing beds of the plant would be modified according to title 40 CFR part 503, the standard of Pathogen Reduction class B would be achieved. Waste sludge of drying bed must be applied in agricultural land with respect to the conditions of application method that is presented in vector attraction reduction. Concentration of this waste sludge is less than ceiling concentration limits identified by title 40 CFR parts 503.

According to Environmental Protection Organization of Iran, maximum permissible concentration of residual phosphorus in treated municipal wastewater is 1 mg /l-P. The total average phosphorus concentration in raw municipal wastewater is about 8 mg / l; about 70 percent of the incoming phosphorus normally is discharged with secondary treatment plant effluents. In this research, the role of adding different kinds of coagulants on phosphorus removal efficiency of an electrochemical process was investigated. The research is a bench scale experimental type using batch system for elec. process with direct current. Samples were collected from an extended aeration effluent. The used electrode was steel type and its total effective area was 336 cm2. In each run 1500 ml of sample was placed in an electrolytic cell equipped with magnetic stirrer. The results show that phosphorus removal efficiency increases by increasing of DC and reaction time. Minimum rate of current/percentage of removal was obtained for 0.6amp current and under the same conditions minimum rate of reaction time/percentage of removal was provided in 15 min. In 6min reaction time and 0.6amp current, adding poly aluminum chloride (PAC) up to about 27 mg/l could improve the efficiency up to about 50%. But under the same condition, similar results were not observed in 12min reaction time. Besides, adding alum or ferrous sulfate showed similar behavior to PAC. Electrochemical treatment without addition of coagulants and thereby without any changes on the primary characteristics of the sample can remove the phosphorus up to about 93%. But in the case of sufficient reaction time for electrochemical process, adding coagulants can not improve the efficiency and in comparison to a chemical precipitation alone, the use of electrochemical treatment can not reduce the required doses of coagulants in short reaction time.

Several authors have indicated that PCP is a toxic chemical and recalcitrant to biodegradation. AOPs is one of the moste effective process for degradation of persistant compound.Since the mineralization of recalcitrant compound by AOPs (Advanced Oxidation Processes) often requires long reaction time and strong doses of oxidant, the combination of this process with biological one, considered as an efficient and economic method. In this worke degradation of pentachlorophenol in aqueous solution with fenton reagent (H2O2 +Ferrous ion)was studied. The experiment was done in batch mode, and the initial concentration of PCP was 0.055mM, in pH=3, H2O2=0.6mM, Fe=0.2mM, more than 95% of PCP was degraded in first minute after the reaction was started.Therefor this reaction is very fast and in the initial phase degredation of PCP follows first order kinetics and kineticts constant (K) was 0.026 (S-1). Chloride ion generatation as PCP degredation by product was investigated, and it was found that the scavenging effect of chloride is negligible. pH and UV215 absorbance analysis, after reaction completion, indicated that generated intermediates have the less chlorinated nature, acidic properties and nonphenolic structure. Chloride ion increases from 0 mg/L to 6 mg/L, pH decreases from 3 to 2.82 and UV215 absorbance decreasees from 0.48 to 0.1, therefor it can be resulted that their biodegradability modified and their recalcitrance reduced. In the long time reaction (10hr) experiments, TOC and COD analysis indicated that PCP did not mineralize and TOC and COD reduction was only 20% and 30% respectively. Results from this study indicated that scavenging effects of generated intermadiate is important in highe doses of H2O2.

Giardia is one of the most common human parasites and causes a lengthly course of nonbacterial diarrhea. Disease outbreaks due to Giardia infection are often attributed to contaminated water supplies. A major problem associated with detection for this organism is the lack of sensitive and reliable methods. PCR has the potential to address many of the limitations.We have performed a PCR based method for sensitive detection of Giardia cysts. Because the sensitivity of PCR is a function of the efficiency of DNA extraction from cysts, we have also compared some different methods for DNA extraction from the cysts. Giardia cysts were collected from infected human, partially purified and serially diluted samples were prepared. DNA was extracted by 3 different methods and we found that simple repeated freezing and thawing was the best method for extraction of DNA from the cysts. A 163 bp conserved fragment related to the giardial heat shock protein (HSP70) gene was used as the target for PCR amplification. We were able to detect as few as 5 cysts in the samples. The results suggest the potential utilities of PCR for sensitive detection of Giardia in water sources.