Groundwater Infiltration and Rainfall-Derived Inflow and Infiltration Assessment in Separate Sewer Systems (Case Study: Tehran Urban Area)

Separate sewer networks are designed and built to collect foul sewage from buildings and convey it to wastewater treatment plants (WWTPs). However, due to some holes and cracks on the pipes or unsealed pipe joints, a volume of ground or subsurface water that is placed in saturated or unsaturated zones intrudes sewers and WWTPs. In a condition that the wastewater level in the sewer stands higher than the groundwater level, wastewater leaks into the soil and groundwater and this phenomenon is called sewer exfiltration. Moreover, during a rain event, a part of the precipitation gets into the sewer system through the illicit connection of the yard drains and roof downspouts to the building’s lateral, and this part of the flow is called rainfall-derived inflow and infiltration (RDII). In this research, infiltration, exfiltration, and RDII were evaluated in a 16-month period to show the range of inflow and infiltration in the sewer network under the service of the South Tehran WWTP. Results show that the infiltration constitutes the major volume of the total inflow and infiltration. But the RDII leads to more operational problems due to its nature as an intense flow. After calculating the range of inflow and infiltration, results show that the average infiltration rate that entered the WWTP in the year 2014 was 0.0175 L/s/ha that is much less than the values mentioned in Criterion No. 118. Furthermore, total inflow and infiltration in five hours of the study period crossed the upper limit of the inflow and infiltration range (0.6 L/s/ha) in Criterion No. 118 that shows the high percentage of illicit connections in Tehran and a high volume of rainfall that enters the sewer network. Accordingly, the inflow and infiltration range in the Criterion No. 118 seems to be an unsound range and it needs some revisions

Analyzing and studying educational pyramid and changes in demographical indices of Tehran students during the school years 2000-2010

One of the effective factors in planning is paying attention to the increase and decrease of student population. In this study, using a variety of resources, it has been attempted that the growth changes and population decrease in the student population of Tehran in a 10-year period and considering the measures such as population density in-class students, the educational staff ratio, academic pyramid, the separation of school, number of classes and other aspects will be dealt with. Obviously, the results and findings of this potential research could be used in educational planning and population policy. In the present study, the method of data collection was done using the quantitative techniques of demography and a variety of statistical calculations. The research findings showed that the student population, number of classes and schools and the staff of ministry of education are being significantly decreased and has been associated with a negative growth rate in all levels

Analyzing and studying educational pyramid and changes in demographical indices of Tehran students during the school years 2000-2010

One of the effective factors in planning is paying attention to the increase and decrease of student population. In this study, using a variety of resources, it has been attempted that the growth changes and population decrease in the student population of Tehran in a 10-year period and considering the measures such as population density in-class students, the educational staff ratio, academic pyramid, the separation of school, number of classes and other aspects will be dealt with. Obviously, the results and findings of this potential research could be used in educational planning and population policy. In the present study, the method of data collection was done using the quantitative techniques of demography and a variety of statistical calculations. The research findings showed that the student population, number of classes and schools and the staff of ministry of education are being significantly decreased and has been associated with a negative growth rate in all levels

Comparing the performance and problems of pre-school centers and kindergartens in Varamin city in Iran

The necessity to examine the performance and problems of pre-school course is due to the significant effect of this course in the child's growth. In this descriptive study, we used systematic perspective to survey and the statistical community is all the managers, coaches and parents of pre-school centers of Varamin in academic year of 2012-13 (2772 people). The sample size is 598 people, according to Morgan table collecting information has been done through observation, interviews, questionnaires and in library and validity of tool research was approved by the teachers and the coefficient of 941/0 = α was calculated, which is an indicative of appropriate stability. To analyze the data, descriptive and inferential statistics were used. The results indicated that there is a significant difference in performance and problems in preschool centers under the protection of education and welfare centers in the size of input, process and environment

Comparing the performance and problems of pre-school centers and kindergartens in Varamin city in Iran

The necessity to examine the performance and problems of pre-school course is due to the significant effect of this course in the child's growth. In this descriptive study, we used systematic perspective to survey and the statistical community is all the managers, coaches and parents of pre-school centers of Varamin in academic year of 2012-13 (2772 people). The sample size is 598 people, according to Morgan table collecting information has been done through observation, interviews, questionnaires and in library and validity of tool research was approved by the teachers and the coefficient of 941/0 = α was calculated, which is an indicative of appropriate stability. To analyze the data, descriptive and inferential statistics were used. The results indicated that there is a significant difference in performance and problems in preschool centers under the protection of education and welfare centers in the size of input, process and environment

Comparing the performance and problems of pre-school centers and kindergartens in Varamin city in Iran

The necessity to examine the performance and problems of pre-school course is due to the significant effect of this course in the child's growth. In this descriptive study, we used systematic perspective to survey and the statistical community is all the managers, coaches and parents of pre-school centers of Varamin in academic year of 2012-13 (2772 people). The sample size is 598 people, according to Morgan table collecting information has been done through observation, interviews, questionnaires and in library and validity of tool research was approved by the teachers and the coefficient of 941/0 = α was calculated, which is an indicative of appropriate stability. To analyze the data, descriptive and inferential statistics were used. The results indicated that there is a significant difference in performance and problems in preschool centers under the protection of education and welfare centers in the size of input, process and environment

Standardization of a trauma symptoms checklist for children

Background: The aim of this study was to standardize and assign validity and reliability of the Trauma Symptom Checklist for Children (TSCC-A). Methods: Normative data for the TSCC-A were based on 3042 students participating in a prevalence child abuse study in 19 different locations of Tehran and 140 participants who had been refered to the run-away children centers in Tehran. After the TSCC was validated on run-away and abused children, it was made available to researchers doing larger studies on a normative group. Results: Reliability analysis of the TSCC-A scales in the normative sample demonstrated high internal consistency. The evidence for its validations (convergent, discriminant and construct validity) showed that they were significantly acceptable. Conclusion: This paper presents data demonstrating the psychometric reliability and validity of the TSCC-A scales in the Iranian student population. We suggest to include the TSCC-A in a battery of relevant standardized tests