development of a simplified concept for process benchmarking of urban wastewater management xây dựng một phương pháp đơn giản cho benchmarking ngành quản lý nước thải đô thị

[ Le Quynh Dung DEVELOPMENT OF A SIMPLIFIED CONCEPT FOR PROCESS BENCHMARKING OF URBAN WASTEWATER MANAGEMENT MASTER THESIS Hanoi - 2011 DRESDEN UNIVERSITY OF TECHNOLOGY VNU UNIVERSITY OF SCIENCE [ Le Quynh Dung DEVELOPMENT OF A SIMPLIFIED CONCEPT FOR PROCESS BENCHMARKING OF URBAN WASTEWATER MANAGEMENT Major: Waste Management and Contaminated Site Treatment MASTER THESIS SUPERVISOR: PROF. DR. RER. NAT DR. H. C PETER WERNER MSC-ENG. PHAN HOANG MAI Hanoi - 2011 DRESDEN UNIVERSITY OF TECHNOLOGY VNU UNIVERSITY OF SCIENCE 1 TABLE OF CONTENTS ABBREVIATIONS 3 LIST OF FIGURES AND TABLES 4 ACKNOWLEDGEMENTS 5 INTRODUCTION 6 CHAPTER I 8 Theoretical Foundations of Urban Wastewater Management System 8 1.1 Characteristics of Urban Wastewater 8 1.1.1 What is Urban Wastewater? 8 1.1.2 Constituents of Wastewater 8 1.2 Overview of the Urban Wastewater Management System 22 1.2.1 Components of Urban Wastewater Management System 22 1.2.2 Types of Wastewater Management System 23 1.3 Sub-processes of Wastewater Management System 26 1.3.1 Collection Systems 26 1.3.2 Wastewater Treatment 28 1.3.3 Sludge Treatment and Disposal 36 1.3.4 Effluent Disposal and Reuse 37 1.4 Current situation of Urban Wastewater Management in Vietnam 37 1.4.1 The Development of the Urban Drainage System 37 1.4.2 Current Structure and Operation of Urban Drainage Systems 38 1.4.3 The Organizations of Urban Drainage Services in Vietnam 39 1.4.4 Financial Aspects of Urban Drainage Companies 40 1.4.5 Legal and Institutional Frameworks 40 1.4.6 Investment and Management of Urban Drainage System 41 CHAPTER II 42 Benchmarking in the Urban Wastewater Management Sector 42 2.1 Fundamentals of Benchmarking 42 2.1.1 Definition of benchmarking 42 2.1.2 Types and elements of benchmarking 43 2.2 International Benchmarking System in Water Industry 46 2.2.1 Benchmarking of large Municipal Wastewater Treatment Plants in Austria 46 2.2.2 Benchmarking in Canada 48 2.2.3 North European Benchmarking Co-operation 49 2.3 Process Benchmarking in Wastewater Sector 52 2.3.1 What is Process Benchmarking? 52 2.3.2 The Objectives of Process Benchmarking 52 2.3.3 Methodology in Process benchmarking 53 2.3.4 Different Process Benchmarking Concepts 53 2 CHAPTER III 55 Performance Indicators of Benchmarking in Wastewater Service 55 3.1 Basis of Performance Indicators 55 3.1.1 Systems of Performance Indicators 55 3.1.2 The Usage of Performance Indicators (PIs) 57 3.1.3 Performance Indicators – A component of Benchmarking 59 3.2 The System of IWA-PIs for Wastewater Services 60 3.2.1 Context Information 60 3.2.2 Performance Indicators 62 CHAPTER IV 65 Performance Assessment and Data Collection for Benchmarking in Wastewater Services of Vietnam 65 4.1 Approach of the Performance Assessment 65 4.1.1 Classification of various Undertakings 65 4.1.2 Performance Indicators 66 4.1.3 Confidence Grades 67 4.1.4 Structure of Questionnaire 67 4.2 Questionnaire of Wastewater Management System 68 4.3 Performance Indicators for Wastewater Management System 79 4.3.1 Environmental Impacts 79 4.3.2 Operation and Maintenance 80 4.3.3 Quality of services 86 4.3.4 Employees 89 4.3.5 Economic and financial aspects 90 4.4 Data Collection 92 CONCLUSIONS 93 REFERENCES 95 APPENDIX 99 3 ABBREVIATIONS CSOs CI EWA IWA NEBC No. PIs p.e. WWTPs Combined Sewer Overflows Context Information European Water Association International Water Association North European Benchmarking Co-operation Number Performance Indicators Population Equivalent Wastewater Treatment Plants 4 LIST OF FIGURES AND TABLES Figures Figure 1.1 Representation of a Centralized Wastewater Collection and Treatment System Figure 1.2 Representation of a Decentralized Wastewater Collection and Treatment System Figure 1.3 Schematic of unit operations and processes in a wastewater treatment plant Figure 1.4 Schematic of plug flow and complete mix activated sludge process Figure 1.5 Schematic of trickling filter with rock packing and plastic packing Figure 2.1 Main steps of a benchmarking process Figure 2.2 Extended process model for wastewater treatment plants above 100,000 PE Figure 2.3 Methodology for the development of process performance indicators Figure 2.4 NEBC’s benchmarking model Figure 2.5 Procedure of process benchmarking Figure 3.1 Structure of Wastewater Context Information & Performance Indicator Figure 3.2 Wastewater undertaking context Tables Table 1.1 Principal constituents of concern in wastewater treatment Table 1.2 Important metals in Wastewater Management Table 1.3 Comparison of ratios of various parameters used to characterize wastewater Table 1.4 Typical wastewater flowrates from urban residential sources in the USA Table 1.5 Typical wastewater flowrates from commercial sources in the USA Table 1.6 Typical composition of untreated domestic wastewater Table 1.7 Typical wastewater constituent data for various countries Table 1.8 Major biological treatment processes used for wastewater treatment Table 2.1 Holistic approach versus Selective approach in Process benchmarking Table 3.1 Reliability bands of collected data Table 3.2 The IWA Performance Indicators Table 4.1 Summary of Performance Indicators for Urban Wastewater Management 5 ACKNOWLEDGEMENTS This thesis has been developed in Dresden, Germany with the support of some people to whom I would like to express my special thanks. I would like to thank Prof. Nguyen Thi Diem Trang - Hanoi University of Science and Prof. Bernd Bilitewski - Institute of Waste Management and Contaminated Site Treatment (IAA), Dresden University of Technology (TUD) as well as DAAD because of giving me the chance to do my thesis in Germany. I would like to send my special thanks to Msc. Phan Hoang Mai, (IAA-TUD), who gave me this topic, supervised and encouraged me to write my thesis. I have learnt some things for my studying from her. Also I would like to thank Dr. Catalin Stefan (IAA-TUD) because of his kind help during the time I was in Dresden. Thanks are also expressed to Msc. Le Thi Hoang Oanh (IAA-TUD) who was always willing to help me as I need. Especially, I would like to thank my family and friends, who always support and encourage me to finish my thesis. 6 INTRODUCTION Wastewater Management is one of the most concerns in any urban area. An efficient management contributes to the wealth of a community, never the less a poor management leads to unpredictable hazards related to health, environmental pollution, etc. In developed countries, the issues of water and sanitation are solved, floodings are well controlled. However, the issues of water supply and sanitation are not solved in developing countries, poor management of floodings as well as improper operation and maintenance of sewer systems are very popular. Therefore, it is an urgent requirement to improve the system of wastewater management in developing countries. Benchmarking is promised to be a solution to this problem as it is always the useful tool for improvement in management. Benchmarking was first time introduced by Xerox Company in the late 1970s when their peer company Fuji produced the photocopiers with better quality and lower prices. Xerox was forced to critically review their products and production costs by adopting the Japanese philosophy: gaining the best of the bests by learning, adapting and improving (Parena et al., 2001). That was how benchmarking appeared. In many countries experiences (Xerox model inspired) have been developed to adapt benchmarking procedures in the water context (Parena et al., 2001). Benchmarking has been conducted in many developed countries such as Australia, Canada, England, Germany etc. to assess the performance of water and wastewater service providers, to estimate the quality of services as well as the satisfaction of customers. These benchmarking projects have achieved initial success and are supposed to sustain. Some systems of performance indicators have been developed with the purpose of large scale application such as the system International Water Association or Qualserve system, etc. In some developing countries such as India, Vietnam, etc. certain benchmarking projects regarding the issue of water and sanitation have been carried out under the support of the World Bank. Aiming at developing a simplified concept for process benchmarking of urban wastewater management which can be applied in developing countries, performance indicators and questionnaire prepared for benchmarking in Vietnam, a representative of developing 7 countries are adapted in this thesis based on the International Water Association (IWA) system of performance indicators for wastewater services. There are four chapters in the thesis. Chapter I considers the foundation of urban wastewater management in general and the current situation of wastewater management in urban areas of Vietnam. In chapter II, fundamentals of benchmarking and process benchmarking for the water industry are discussed. To make clear the tool of performance assessment presented in the thesis the performance indicators for wastewater services of IWA as well as the basis of performance indicators are given in chapter III. Chapter IV explains the performance indicators selected for process benchmarking in wastewater services of Vietnam; also, the questionnaire as well as the excel file to collect data from wastewater undertakings are presented. Benchmarking of wastewater utilities is emerging as an important tool of performance improvement by regular monitoring and analyses can be the solution to this reality. It can play a significant role in the sector as a tool for institutional strengthening. Sustained benchmarking can help utilities in identifying performance gaps and gaining improvements by the sharing of information and best practices, ultimately resulting in better services to people. It is expected that benchmarking in wastewater services in developing countries will soon be supported to implement. 8 CHAPTER I Theoretical Foundations of Urban Wastewater Management System In this chapter the theoretical foundations of urban wastewater management will be considered, including: (1) characteristics of urban wastewater, (2) overview of the urban wastewater management system, (3) sub-processes of wastewater management system and (4) current situation of urban wastewater management in Vietnam. 1.1 Characteristics of Urban Wastewater 1.1.1 What is Urban Wastewater? According to Tchobanoglous et al. 2003, urban wastewater components may vary depending on type of collection system and may include: 1. Domestic (sanitary) wastewater. Wastewater discharged from residential areas, and from commercial, institutional and similar facilities. 2. Industrial wastewater. Wastewater in which industrial wastes predominate. 3. Stormwater. Runoff resulting from rainfall 4. Infiltration/Inflow. Water that enters the collection system through indirect and direct means. Infiltration is extraneous water that enters the collection system through leaking joints, cracks and breaks, or porous walls. Inflow is stormwater that enters the collection system from storm drain connections, roof leaders, foundation and basement drains, or through access port (manhole) covers. 1.1.2 Constituents of Wastewater The constituents of wastewater can be classified as physical, chemical and biological. Of the constituents listed in table 1.1, suspended solids, biodegradable organics and pathogen organisms the most concerning ones are referred. All wastewater treatment facilities are designed to remove these constituents completely. 1.1.2.1 Physical Characteristics Solids There are many kind of solids present in wastewater, varying from coarse to colloidal ones. Before any analysis of solids in wastewater the coarse material should be removed. In wastewater treatment, the solids can be classified by their size and state (suspended solids & [...]... 10-1-103 a: From Tchobanoglous et al., 2003 b: Low strength is based on an approximate wastewater flowrate of 750 L/capita.d Medium strength is based on an approximate wastewater flowrate of 460 L/capita.d High strength is based on an approximate wastewater flowrate of 240 L/capita.d c: Values should be increased by amount of constituent present in domestic waster supply 21 Table 1.7 Typical wastewater. .. that may arise from nonhuman sources Therefore the use of new indicator bacteriophages is much more concerned (Tchobanoglous et al., 1998) 1.1.3 Flowrates and Composition of Wastewater The analysis of wastewater data involves the determination of the flowrate and mass loading variations From the standpoint of treatment processes, average flowrates and average BOD and TSS loadings are two of the most... feces therefore wastewater contain both pathogenic and nonpathogenic bacteria One of the most common pathogenic organisms found in domestic wastewater is the genus Salmonella The Salmonella group contains variety species causing diseases to human and animals Other bacteria isolated from raw wastewater which causes cholera is Vibrio cholerae Protozoa Because of their significant impact on individuals with... wastewater may be discharged by human who are suffering with diseases or who are carriers of a particular disease The pathogenic microorganisms found in wastewater can be classified into three broad categories: bacteria, parasites (protozoa and helminths) and viruses Bacteria There are many types of harmless bacteria in human intestinal track and human feces Pathogens are only found in the infected humans... in wastewater, (2) pathogenic organisms related to human diseases, and (3) the use of indicator organisms Microorganisms found in wastewater The microorganisms found in wastewater can be classified as eukaryotes, eubacteria and archaea Their cell structure, typical size, characterization and representative member are illustrated in table 1 (appendix) Pathogenic Microorganisms Pathogens found in wastewater. .. Lagoon processes Aerobic lagoons Aerobic lagoons Carbonaceous BOD removal Maturation lagoons Maturation (tertiary) lagoons Facultative lagoons Facultative lagoons Anaerobic lagoons Anaerobic lagoons Carbonaceous BOD removal, nitrification Carbonaceous BOD removal Carbonaceous BOD removal, waste stabilization a : From Tchobanoglous et al., 2003 33 Suspended growth processes In suspended growth processes,... Schematic of (a) plug flow and (b) complete mix activated sludge process (Source: Tchobanoglous et al., 2003) Attached growth processes In attached growth processes, the microorganisms responsible for biodegradation of organic materials or nutrients are attached to an inert parking material The organic material and nutrients are removed from the wastewater flowing past the attached growth known as biofilm... industrial activities Industrial variations are difficult to predict and 18 the most troublesome in smaller wastewater treatment plants where the loading capacity is limited (Tchobanoglous et al., 2003) The principal sources of domestic wastewater in a community are the residential areas and commercial districts Data on ranges and typical flowrate values from urban residential and commercial sources... such as iron, copper, zinc for proper growth Though certain amounts of metals are necessary, the elevated concentration of them can be toxic to all kinds of creatures Therefore, metals are always the concern in wastewater treatment (Tchobanoglous et al., 1998) The sources of metals in wastewater include residential areas, groundwater infiltration, commercial and industrial discharges The importance of. .. degree of treatment and type of plant required Treated wastewater can be discharged into lakes, rivers or the ocean The reuse of treated effluent can be applied for groundwater recharge, irrigation, etc These issues will be referred later 1.2.2 Types of Wastewater Management System There are two typical types of wastewater management system, including centralized and decentralized model The former . foundation of urban wastewater management in general and the current situation of wastewater management in urban areas of Vietnam. In chapter II, fundamentals of benchmarking and process benchmarking. characteristics of urban wastewater, (2) overview of the urban wastewater management system, (3) sub-processes of wastewater management system and (4) current situation of urban wastewater management. of Urban Wastewater 8 1.1.1 What is Urban Wastewater? 8 1.1.2 Constituents of Wastewater 8 1.2 Overview of the Urban Wastewater Management System 22 1.2.1 Components of Urban Wastewater Management