نتایج جستجو برای: four processes of urban wastewater treatment includes activated sludge

تعداد نتایج: 21342650  

this thesis attempts to investigate the effects of prelistening activities on enhancing iranian efl learners` listening comprehension. the present study investigated ways in which learners` background knowledge could be activated in order to enhance their l2 listening comprehension by limiting the number of possible text interpretations prior to listening. the experiments conducted in this study examined the effect of prior knowledge and vocabulary teaching on iranian efl learners listening comprehension. the current study has two purposes: one is to investigate the effect of background knowledge on the second language listening comprehension of iranian intermediates and the other is to determine whether second language is facilitated by the introduction of unknown vocabularies in the form of prelistening activities. to conduct the study different instruments such as listening proficiency test and four listening tests such as pre and posttests were used and various statistical processes and techniques including paired-sample t-test, and analysis of variance (anova) were used. the findings of this study supported all three hypotheses tested. differences were found between the means of preteaching vocabulary variable, the background knowledge activation variable, and mean difference between these two strategies variable. subjects scored higher when the unknown words were taught in advance. likewise, subjects scored higher when they were asked some relevant questions about the topic than on those without them. there was, in addition, a significant difference between the means of preteaching vocabulary strategy and background knowledge activation strategy. in fact, preteaching vocabulary had a better effect in enhancing the students’ listening comprehension, in comparison to background knowledge activation strategy.

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده زبانهای خارجی 1390

this thesis attempts to investigate the effects of prelistening activities on enhancing iranian efl learners` listening comprehension. the present study investigated ways in which learners` background knowledge could be activated in order to enhance their l2 listening comprehension by limiting the number of possible text interpretations prior to listening. the experiments conducted in this stud...

2016
Sunil Jayant Kulkarni

The wastewater from petroleum industries contains high organic matter content, oil and grease, dissolved solids and turbidity. The petroleum wastewater normally treated in a plant comprising of primary, secondary and tertiary treatments. The high organic loading needs to be treated in biological treatment step. Biological treatment can be suspended growth or attached growth type. Activated slud...

Journal: :Bioprocess and biosystems engineering 2009
D P Mesquita O Dias A L Amaral E C Ferreira

In recent years, a great deal of attention has been focused on the research of activated sludge processes, where the solid-liquid separation phase is frequently considered of critical importance, due to the different problems that severely affect the compaction and the settling of the sludge. Bearing that in mind, in this work, image analysis routines were developed in Matlab environment, allow...

2013
ALEXANDROS G. ASIMAKOPOULOS KURUNTHACHALAM KANNAN NIKOLAOS S. THOMAIDIS

Despite the widespread use of benzotriazoles and benzothiazoles and the occurrence of these compounds in wastewater treatment plants (WWTPs), no earlier study has comprehensively examined their fate in WWTPs. In this study, an integrated liquid chromatography-tandem mass spectrometry (LC–ESI(+)MS/MS) method was developed and validated for simultaneous determination of four benzotriazoles and fo...

1999
Tongchai Sriwiriyarat

The Integrated Film Activated Sludge Process (IFAS) was developed to reduce the cost of additional facilities required to complete year round nitrification in the design of new or retrofit wastewater treatment plants. The purpose of this project was to develop a computer-based mechanistic model, called IFAS, which can be used as a tool by scientists and engineers to optimize their designs and t...

Background and purpose: Dewatered sludge of sewage treatment plants can be used in agriculture if required standards are followed. Heavy metals are among the chemical pollutants that are hazardous to health. Therefore, the aim of this study was to investigate the amount of heavy metals in dewatered sludge of municipal wastewater treatment plant and compare that with the standards and sludge of ...

2012
Amr Abdel Kader

Comparison study is required to evaluate the treatment efficiency of three alternative secondary treatment processes. These Processes are Integrated Fixed-film Activated Sludge (IFAS), Membrane Bioreactor (MBR) and Conventional Activated Sludge (AS). This study is required for a new wastewater treatment plant. The characteristics of the influent domestic wastewater for the proposed plant were m...

2014
Xiaohui Wang Yu Xia Xianghua Wen Yunfeng Yang Jizhong Zhou

BACKGROUND Biological WWTPs must be functionally stable to continuously and steadily remove contaminants which rely upon the activity of complex microbial communities. However, knowledge is still lacking in regard to microbial community functional structures and their linkages to environmental variables. AIMS To investigate microbial community functional structures of activated sludge in wast...

2003
C.-K. Chen

This study combines a two-phase biological treatment system of activated sludge/contact aeration process by adding biological contact filters into the rear sector of the activated sludge aeration tank of the slaughterhouse wastewater treatment plant. This system keeps the advantages of complete mixing of substrates and microorganisms and flexible operation of the activated sludge process, and i...

2014

The disposal of domestic wastewater without any treatment into the drainage systems is considered a source of pollution threatening the population. Industrial waste water discharge to the environment is one of the environmental problems which must be controlled. Current mainstream technologies for treatment of domestic wastewater such as activated sludge and tertiary nutrient removal are too co...

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