Introduction: The limitation of fresh water resources in the world, especially in arid and semi-arid regions such as Iran, has inevitably led to the reuse of urban wastewater. One of the most important indicators of sewage pollution and comparison with different standards for reuse or discharge to the water resources is TSS. The present study was conducted in 2016 with the aim of estimation of effluent TSS of Ahvaz wastewater treatment plant using inelegant models. Material and methods: Regard to costly and time-consuming measurement T.S.S of TSS, the capability of multivariate linear regression model, Artificial Neural Network (ANN), and Adaptive Neuro-Fuzzy Inference System (ANFIS) was studied to estimate (TSS) in wastewater treatment plant output by MATLAB and SPSS 21 software. Accordingly, various compounds of sewage quality parameters were evaluated during the 8-year statistical period (2008-2015) as input of models in two daily and monthly modes. Results: The results of the regression model indicated that the maximum R2 for training and verification were 0. 75 and 0. 67 in daily and 0. 68 and 0. 66 in monthly period, respectively. The root mean square error (RMSE) in this test was 0. 033 and 0. 025 in the daily period and 0. 053 and 0. 053 in the monthly period. The maximum R2 in ANN for training and verification were 0. 87 and 0. 79 in daily and 0. 87 and 0. 85 in monthly period, respectively. The RMSE in this test was 0. 030 and 0. 023 in the daily period and 0. 034 and 0. 031 in the monthly period. Meanwhile, the maximum R2 in ANFIS for training and verification were 0. 91 and 0. 83 in daily and 0. 89 and 0. 87 for monthly period, respectively. The RMSE in this test was 0. 026 and 0. 025 in the daily period and 0. 031 and 0. 028 in the monthly period. Conclusion: The results confirmed the application of three models is appropriate, but the ANFIS was considered as a more appropriate model.

The aim of this study was to examine renormalization of Kyriacou and Sutcliffe's teachers' stress prevalence, source and symptoms scale (TSS) through factor analysis and assessing its validity and reliability. 430 male and female teachers, consisting of both physical education and non- physical education high school teachers at West Azarbaijan province filled out the TSS questionnaire. Diffluent and convergent validity of TSS were computed through determining coefficient of correlation by Mental Health Inventory (MHI) as well as Job Descriptive Index (JDI). TSS reliability was calculated through tester test and internal consistency. Reliability and validity indices obtained for TSS were satisfactory and significant at p<0.01. Seven factors were obtained by factor analysis applying varimax method. These factors had eigenvalues higher than I and 49041 percent of the total variance was explained by them. The seventh factor was removed because its reliability was lower than 0.7. The Remaining six factors are: teacher's inappropriate socioeconomic and family statues, issues concerning the school’s atmosphere and facilities, students' behavior problems and difficulties, teachers' professional qualifications, students' low amount of educational motivation and time pressure. Regarding the source and symptoms of stress, criterion validity concerning those who had stressful experiences during the past 12 months yielded that there was significance difference between two groups with low and high stress. Results showed that 8.2, 18.1, 40.0, 30.5 and 3.2 percent of the teachers were at non-risk, low risk, average risk, high risk and extreme risk areas, respectively, but none of them were at the critical area. According to the results of the research, T.S.Scale had necessary psychometrics characteristics to be applied at psychological research and clinical diagnosis in investigation of the teachers' stress.

Sand filters are composed of sand-filled containers with determined granulation and specified thicknesses of pressurized sand layers that work under pressure and they are placed in the center control system after the cyclone and before the grid or disk filter. The aim of this study was to determine the relationship between water turbidity and Total suspended solids (TSS). To determine the samples turbidity, they were tested using a spectrophotometer and the percentage of light passing was obtained through each sample separately. The test of determining total suspended solids was also performed. The results of this experiment showed that there is a quadratic equation between the percentage of light passing and total suspended solids, which is presented as the main equation from figure 3, that is more correlated with the data. As can be seen, at 450 nm, there is a higher correlation between the turbidity and the light transmittance and less error.

Background and Purpose: Waste stabilization ponds as a natural treatment method have been found among successful methods in municipal wastewater treatment. They are very costeffective in energy and manpower. Low efficiency rates and vast area required are some of their drawbacks which are less attended to. Therefore this study intends to research the optimization methods in anaerobic ponds.Methods and Materials: In this experimental study, two anaerobic ponds were built in pilot scale with 48 hours detention time, 12 m2 area (6x2 m) and 4m depth. The control pond was a conventional pond; the optimized pond was built in two parts: a digestion pit and a detention time of 12 hours, and the anaerobic pond with 8 baffles with a detention time of 36 hours. The wastewater with BOD5=250 mg/l and TSS=320 mg/l from municipal network in Sabzevar, Iran was used; the pilot took one year from December 2006 to December 2007. The collected data were analyzed in Excel and Tsp7.Result: Average removal efficiency for BOD5 and TSS in the conventional pond were 37% and 53% respectively; the figures for the optimized pond were 68% and 85% respectively. Conclusion: Using optimized anaerobic ponds enhances the removal efficiency rate.

Although the conventional (primary and secondary) treatment processes are known to remove up to 95–99% of some micro-organisms, they do not provide adequate treatment to make the effluent suitable for direct reuse, mainly due to the presence of high concentrations of pathogenic microorganisms. Obtaining reusable effluents, therefore, requires the use of processes that can be justified both technical and economic grounds. One such indigenous, low cost option is the land-plant process that can be used for advanced wastewater treatment. It is the objective of the present study to determine the efficiency of the local soil in Ahvaz and that of the vetiver plant in reducing the microbial load in the effluent from municipal wastewater treatment plants. A pilot study was thus carried out including three Lysimeters installed in West Ahvaz Wastewater Treatment Plant. Local soil was used in one Lysimeter, local soil with vetiver plant in the second one, and an artificial assortment of soil comprising local soil, silica sand (0.5-1mm), and sand (15-30mm) in the third. In addition, the effluent from the secondary settling outlet at the WTP was transferred by pumping at the three filtration rates of 0.2, 0.6, and 1 ml/min into the system with three replications for each rate and samples were collected from both inlet and outlet flows. The average removal efficiencies of Total Suspended Solids (TSS) and Total Coliform (TC) in the effluent from the three Lysimeters with local soil with vetiver, local soil without vetiver, and artificial soil assortment for the filtration rate of 0.2 ml/min were: 67.75% and 99.7%, 58.33% and 99.6%, and 56.25% and 99.5%, respectively. For a filtration rate of 0.6 ml/min, these values were: 53.33% and 98.93%, 48.8 and 98.77%, and 47.68% and 98.64%. Finally, the values obtained for a filtration rate of 0.6 ml/min were: 50% and 93.96%, 46.42 and 91.34%, and 44.04% and 88.81%, respectively. The results from the study showed that the Lysimeter with local soil and the vetiver plant recorded the best removal efficiency for a filtration of 0.2 ml/min. Thus, it may be concluded that the land-planT.S.Stem as an advanced treatment process is capable of producing effluents that meet discharge quality permit limits and therefore, it is an economical process using the advantages of advanced treatment if enough and available lands possible.

The aim of this research was investigation on the performance of an electrocoagulation process with aluminum sacrificial anode for removal of TSS and COD from effluent of a paper recycling mill. The effect of electrolysis time (10, 20, 30 and 60 min), initial electrolyte pH (3, 5, 7.5 and 10), and voltage (9 and 12V) were studied on the electrocoagulation efficiency. Increase of voltage from 9 to 12 V caused significantly removal of TSS and COD which the highest removal rate at 12 voltages for TSS and COD were 99%, and 77%, respectively, while the values for the same parameters at voltage 9 were 97% and 33%. The results also show that the initial pH of effluent has a key role in process efficiency so that in neutral limit the TSS and COD removal was more than the other pHs. It can be concluded that EC technique can be used as a simple and efficient method for treatment of paper recycling mill effluent and thereby pollution reduction.