Characteristics of 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.
The constituents of wastewater can be classified as physical, chemical and biological.
Suspended solids, biodegradable organics, and pathogenic organisms are the primary concerns among the constituents outlined in Table 1.1 Consequently, all wastewater treatment facilities are specifically engineered to effectively eliminate these harmful components.
Wastewater contains a variety of solids ranging from coarse to colloidal types Prior to analyzing these solids, it is essential to remove the coarse materials In wastewater treatment, solids are categorized based on size and state into suspended and dissolved solids, as well as by their chemical properties into volatile and fixed solids Additionally, solids can be classified by their settleability, distinguishing between settable and non-settable suspended solids (Sperling, 2007).
Table 1.1 Principal constituents of concern in wastewater treatment a
Dissolved inorganics (e.g total dissolved solids)
Sludge deposits and anaerobic conditions
Depletion of natural oxygen resources and the development of septic conditions
Inorganic constituents added by usage Recycling and reuse applications
Metallic constituents added by usage Many metals are also classified as priority pollutants
Excessive growth of undesirable aquatic life, eutrophication, nitrate contamination of drinking water Communicable diseases
Suspected carcinogenicity, mutagenicity, teratogenicity, or high acute toxicity Many priority pollutants resist conventional treatment methods (known as refractory organics) a: From Crites & Tchobanoglous, 1998
Determining particle size is essential for understanding the characteristics of total suspended solids (TSS) in wastewater This analysis plays a crucial role in evaluating the effectiveness of various treatment processes, including biological treatment, disinfection, and sedimentation.
Turbidity measures how much light can pass through water, serving as an important indicator of water quality It assesses the presence of colloidal and suspended particles in both natural water bodies and wastewater discharges, highlighting potential contamination levels.
Color in wastewater arises from suspended solids, colloidal materials, and dissolved substances Apparent color is attributed to suspended solids, while true color results from colloidal matters and dissolved substances.
The sources of color in wastewater include infiltration/inflow (humic substances), industrial discharges (e.g dyes or metallic compounds, etc) and the decomposition of organic compounds in wastewater.
Transmittance refers to a liquid's capacity to allow light of a specific wavelength to pass through a defined depth of the solution, while absorbance indicates the reduction of radiant energy as light travels through the fluid (Tchobanoglous et al., 2003).
Transmittance is influenced by various factors, including specific inorganic compounds like iron and copper, organic compounds such as organic dyes and humic substances, as well as conjugated ring compounds like benzene Additionally, total suspended solids (TSS) play a significant role in this process (Tchobanoglous et al., 2003).
Variety of malodorous compounds released under anaerobic conditions in biological process of wastewater treatment.
Hydrogen sulfide is the primary compound responsible for unpleasant odors, but in anaerobic conditions, other compounds like indole, skatole, and mercaptanes can produce even more offensive smells.
Measuring temperature is crucial in wastewater treatment facilities, particularly during the biological treatment process, which relies on temperature Wastewater temperatures fluctuate based on seasonal changes and geographical location, ranging from 7 to 18°C in colder regions and from 13 to 30°C in warmer areas.
Temperature plays a critical role in aquatic ecosystems, influencing chemical reactions, reaction rates, and the survival of various fish species Elevated temperatures can result in decreased dissolved oxygen levels in water, which may threaten aquatic life Furthermore, the increased biochemical reaction rates associated with higher temperatures can lead to significant oxygen depletion, impacting overall water quality and ecosystem health (Tchobanoglous et al., 1998).
Density, Specific Gravity and Specific Weight
Wastewater density, denoted as ρw, is defined as the mass of wastewater per unit volume, measured in g/l or kg/m³ (SI) This parameter is crucial for designing various treatment systems, including sedimentation tanks and constructed wetlands Understanding wastewater density is essential for effective treatment unit design.
Electrical conductivity (EC) refers to a liquid's capacity to conduct electrical current, which is facilitated by ions present in the solution The EC measurement serves as an indicator of the concentration of total dissolved solids within the liquid.
The electrical conductivity is expressed in SI units as millisiemens per meter (mS/m). 1.1.2.2 Inorganic Chemical Characteristics
Wastewater chemical constituents can be categorized into inorganic and organic types, with a focus on inorganic constituents in this section The pH value serves as a key indicator of the acidity or alkalinity of an aqueous solution, typically measured at temperatures of 20°C or 25°C, on a scale from 0 to 14 (Prichard et al., 2003) Defined as the negative logarithm of hydrogen-ion concentration, pH values are crucial for sustaining biological life, ideally ranging between 5 and 9 When wastewater pH falls below 5 or exceeds 9, it hampers the effectiveness of microorganisms in biological treatment processes Without proper pH adjustments, effluents from domestic wastewater treatment facilities can significantly alter the pH of receiving water bodies (Tchobanoglous et al., 1998).
Nitrogen and phosphorus are crucial nutrients that promote biological growth, acting as biostimulants Nitrogen, in particular, is vital for protein synthesis, making it essential for effective wastewater treatment Wastewater contains various forms of nitrogen, including ammonia, nitrite, nitrate, and organic nitrogen, which is associated with amine groups (Sperling, 2007).
Ammonia exists in aqueous solution in two forms the ammonium ion or ammonia gas, depending on the pH of solution as the following equilibrium reaction:
At pH levels above 9.3, ammonia gas is predominant; at level below 9.3 the ammonium ion is major.
Overview of the Urban Wastewater Management System
1.2.1 Components of Urban Wastewater Management System
Wastewater Management System includes three main components: (1) collection, (2) treatment and (3) disposal or reuse.
Effective wastewater management begins with the collection and transportation of wastewater from diverse sources This process relies on sewers, which are the pipes responsible for gathering and conveying wastewater away from its origins, forming an essential network known as the collection system.
(George Tchobanoglous, 1981) Most sewers are placed underground to prevent interference due to repair of this system (Punmia and Jain, 1998) The types of collection systems will be discussed later.
Wastewater treatment is a crucial component of effective wastewater management, as it minimizes environmental pollutants and safeguards human health from harmful pathogens (Punmia and Jain, 1998) This process involves a combination of various unit operations, employing a range of treatment methods, including mechanical, physical, chemical, and biological techniques, as well as hybrid approaches like physiochemical methods The subsequent sections will delve into the diverse treatment methods available.
After treatment, water can be either disposed of or reused, with the method of disposal closely linked to the self-purification capacity of the receiving water bodies Engineers determine the necessary level of treatment and type of treatment plant based on the chosen receiving water and effluent standards Treated wastewater may be released into lakes, rivers, or oceans, while its reuse can include applications such as groundwater recharge and irrigation.
1.2.2 Types of Wastewater Management System
Wastewater management systems are primarily categorized into two types: centralized and decentralized models Centralized systems, the traditional approach, have been effectively utilized in many industrialized nations for decades, but they often face significant investment and implementation costs that can burden communities In contrast, decentralized wastewater systems, which treat wastewater close to its source, are gaining attention as a viable alternative to the conventional centralized approach This article will explore both wastewater management systems in detail.
Figure1.1 Representation of a Centralized Wastewater Collection and Treatment System
Centralized wastewater management refers to a comprehensive system that gathers wastewater from households, industrial areas, small businesses, and stormwater runoff, transporting it to a treatment facility often located outside urban or village boundaries Once treated to meet regulatory standards, the wastewater is discharged into the nearest water body, while the residual waste sludge undergoes further treatment before any potential reuse.
Decentralized wastewater treatment systems are situated near the sources of waste, resulting in shorter sewer lengths for wastewater transport These systems include on-site treatment plants that handle both wastewater and sludge processing The treated effluent and sludge can then be safely discharged into water bodies or repurposed for applications such as irrigation and toilet flushing (Wilderer and Schreff, 2000).
Figure1.2 Representation of a Decentralized Wastewater Collection and Treatment System
(Source: Wilderer and Schreff, 2000) Advantages and disadvantages
Centralized wastewater management systems have long been successful in developed countries, effectively collecting and transporting sewage and stormwater through a network of sewers These systems ensure advanced treatment and control before discharging treated water into natural bodies Additionally, waste sludge is properly treated, utilized, or disposed of A key advantage of centralized systems is the reliable management of treatment plants, with studies suggesting that one large treatment facility is more cost-effective than multiple smaller plants in terms of capital and operational expenses (Lettinga et al., 2001).
Centralized systems, while beneficial, face significant limitations, primarily due to the high costs associated with extensive sewer infrastructure For instance, Germany invested approximately 1.6 billion euros in 2003 to rehabilitate its 515,000 km sewer system, which serves nearly 82.5 million people These systems are often over-engineered to accommodate projected population growth, resulting in excessive operational costs and inefficient plant performance Additionally, the substantial initial investment pressures local economies Environmentally, the withdrawal of water from one location and the discharge of treated effluent elsewhere disrupts the water balance Furthermore, the combination of wastewater and stormwater from diverse sources complicates pollutant removal, making efficient treatment increasingly challenging.
Decentralized wastewater management systems, commonly found in rural areas, offer significant advantages over centralized systems These benefits include the elimination of the need for lifting stations and storage tanks, resulting in reduced construction, operation, and maintenance costs Additionally, decentralized systems enhance the potential for water reuse and groundwater recharge, as transporting treated wastewater from a centralized plant can be impractical Moreover, failures in individual units do not compromise the entire system's functionality, and these systems are more adaptable to rapid population growth due to their capacity for easy adjustment.
Decentralized wastewater management systems face significant challenges, including low effluent quality that often fails to meet water reuse standards, improper operation of treatment plants, and difficulties in oversight by water authorities Current treatment methods are largely outdated, relying on primitive solutions like pit latrines or low-tech options such as septic tanks Responsibility for the operation and maintenance of these on-site facilities typically falls on the owners; however, most lack the necessary knowledge and motivation to ensure their systems function effectively.
Decentralized systems offer a flexible and straightforward solution for wastewater management, particularly in industrialized and developing countries However, several challenges must be addressed before these systems can be effectively implemented.
Sub-processes of Wastewater Management System
A collection system is essential in urban wastewater management, serving to gather wastewater from both domestic and non-domestic sources, along with stormwater, and transport it to treatment facilities This section will explore the typical components of a collection system and discuss the various types of sewers involved.
1.3.1.1 Typical Components of Collection System
An urban drainage system typically consists of building drainage, roof drainage, and main sewer networks Building drainage is responsible for transporting various types of wastewater to the main sewer, while roof drainage directs stormwater to the same sewer system This section will focus on the essential components, or "hardware," that make up any drainage system (Butler et al., 2004).
Sewers are essential elements of sewerage systems that transport wastewater from multiple properties or larger regions to treatment facilities or natural bodies of water They can be constructed from various materials such as vitrified clay, concrete, or cement, depending on the sewer type There are three main categories of sewers: sanitary sewers, stormwater sewers, and combined sewers (Butler et al., 2004).
Manholes serve as crucial access points in sewer systems for testing, inspection, and clearing blockages Typically deep enough for entry, they are strategically placed at key locations, including changes in direction, heads of runs, gradient shifts, size alterations, and significant junctions with other sewers The diameter of a manhole is determined by the sewer's size, as well as the orientation and number of inlets (Butler et al., 2004).
Gully inlets are essential components of stormwater management, allowing surface runoff to enter the sewer system Each gully features a grating and an underlying sump designed to capture heavy materials from the flow Connected to the sewer via a lateral pipe, gullies incorporate a water seal when linked to a combined sewer system The design, including the size, number, and spacing of gullies, significantly influences surface ponding during storms, with gullies typically positioned at low points along roadways A common guideline suggests spacing gullies every 50 meters or for every 200 square meters of impervious area (Butler et al., 2004).
Ventilation is essential in urban drainage systems, especially in sanitary and combined sewers, to maintain aerobic conditions within the pipes and prevent the accumulation of toxic and explosive gases.
In this section, three types of sewer, including sanitary sewers, stormwater sewers and combined sewers will be introduced very briefly. a/ Sanitary sewer
Sanitary sewers are designed to efficiently collect and transport wastewater from residential, institutional, and industrial sources to treatment facilities This wastewater is moved primarily through gravity systems, known as gravity sanitary sewers, or through pressure and vacuum systems, referred to as pressure sanitary sewers.
When designing sanitary sewers, key factors to consider include design flows, hydraulic design equations, the selection of sewer pipes and materials, and the establishment of minimum and maximum velocities Additionally, it is essential to determine minimum slopes, explore alternative design options, incorporate sewer appurtenances, and ensure adequate sewer ventilation.
Storm-water sewers are specifically designed to collect and manage rainwater runoff, differing from sanitary sewers in key aspects One notable distinction is that storm-water sewers are engineered to handle periodic overflow, accommodating excess water during heavy rainfall events For example, a storm-water sewer designed for a 10-year rainfall frequency anticipates an overflow approximately once every decade.
In the next decade, the sewer system is expected to exceed its capacity, while the sanitary sewer system is specifically designed to avoid surcharge caused by high pollutant levels Surcharge events typically occur only due to unforeseen breakdowns A notable distinction between the two systems is the diameter of their pipes; the sanitary sewer pipe is significantly smaller than that of the stormwater sewer, meaning that even a small amount of excess infiltration can result in overload (Hammer et al., 2008).
The design procedures for storm-water sewers closely resemble those of sanitary sewer systems, with key differences in design flow, minimum velocities, and the materials and sizes of pipes used (Tchobanoglous, 1981).
A combined sewer system collects domestic and industrial wastewater along with rainwater runoff in a single pipe During dry conditions, this wastewater is directed to treatment plants before being released into receiving waters However, during heavy rainstorms, the volume of wet weather flow can surpass the capacity of the sewer network and treatment facilities, resulting in a direct discharge of excess flow into nearby water bodies through a process known as combined sewer overflow (CSO).
The primary function of a Combined Sewer Overflow (CSO) is to manage excess water flow by directing it to either a treatment plant or receiving bodies, typically using a weir for regulation When the water level is below the weir, all flow is directed to the treatment facility; however, when it exceeds the weir, a portion is diverted while the remainder continues to treatment Therefore, careful hydraulic design is essential to prevent premature overflow, which can lead to the discharge of excess polluted water, as well as to avoid surcharging in the sewer system Additionally, CSOs are engineered to minimize the transfer of fine suspended and dissolved materials into the overflow, ensuring that as much as possible is treated before discharge (Butler et al., 2004).
The design of Combined Sewer Overflows (CSOs) is crucial in combined sewer systems, with key factors including the diameter of the inflow pipe, control mechanisms for outflow, weir design, chamber invert elevation, the design return period, top water level, and accessibility for maintenance (Butler et al., 2004).
Wastewater treatment involves several key stages: preliminary processes, primary settling to eliminate heavy solids and floating materials, and secondary biological treatment to break down and flocculate dissolved and colloidal organics The resulting waste sludge is then thickened and prepared for disposal, typically through land application or landfilling If primary and secondary treatments fail to meet regulatory standards, a tertiary treatment step is implemented A schematic representation of the unit operations and processes in a wastewater treatment plant is provided in Figure 1.3.
Current situation of Urban Wastewater Management in Vietnam
1.4.1 The Development of the Urban Drainage System
Between 1858 and 1945, Vietnam initiated the construction of urban drainage systems using brick materials to manage both wastewater and stormwater The collected wastewater was subsequently released into lakes, canals, or rivers (Trinh, 2007).
Between 1945 and 1975, urban sewerage systems expanded significantly, yet this growth lacked proper planning The primary materials used for these sewers were precast concrete and bricks, which have suffered from damage due to inadequate maintenance and destruction caused by wartime bombings (Trinh, 2007).
Between 1975 and 1990, the primary focus was on the unification of South and North, leading to neglect of the sewerage system Following 1990, with the onset of renovation, urban drainage systems gained attention, although they remained a lower priority compared to water supply However, by the early 21st century, authorities recognized the importance of sewerage systems as a critical component of urban infrastructure.
1.4.2 Current Structure and Operation of Urban Drainage Systems
In this section, the current situation of urban drainage systems in Vietnam including collection systems and treatment systems will be discussed.
Many towns with class IV and higher have combined sewer systems that consist of precast concrete pipes, brick canals with concrete covers, open channels, and stabilization ponds These sewerage systems were built without a comprehensive urban development plan, leading to inadequate capacity and insufficient maintenance Additionally, most sewers and canals lack self-cleaning features and proper ventilation, which can result in unpleasant odors during dry seasons (Trinh, 2007).
Currently, towns classified as class V lack adequate drainage systems for stormwater and wastewater, as well as wastewater treatment plants (Trinh, 2007) The prevalence of sanitary latrines among households is alarmingly low, with many relying on bucket toilets and open defecation Although double vault composting latrines exist, they are often poorly maintained While some households have septic tanks, they are not connected to the public sewer system, resulting in wastewater being discharged into small ditches or seeping into the surrounding soil Additionally, improper waste disposal practices, such as throwing rubbish into sewers, canals, and ditches, contribute to blockages and flooding during the rainy season.
The coverage of drainage services in urban areas remains largely unexamined, yet estimates from the Department of Urban Infrastructure and the Vietnam Drainage and Water Supply Association indicate that it is significantly lower than that of water supply services, averaging around 40-50% This disparity ranges from 1-2% in class V towns to 70% in larger urban areas In major towns, the drainage infrastructure provides 0.2-0.5 meters per person, compared to just 0.05-0.08 meters per person in smaller towns Many households rely on septic tanks without connections to public sewer systems, resulting in wastewater being discharged into open ditches or seeping into the ground Additionally, some homes with pour-flush toilets directly release wastewater into public sewer systems without any prior treatment.
In Vietnam, only Da Lat and Ban Me Thuot have wastewater treatment plants funded by ODA loans from Denmark, yet these facilities only manage 40-60% of the total wastewater generated Cities like Ha Long, Vung Tau, and Da Nang possess basic wastewater treatment systems, while Hanoi's two treatment stations in Kim Lien and Truc Bach handle a mere 1.6% of the city's total wastewater Additionally, many other towns lack wastewater treatment plants, with some only in the planning stages.
Urban wastewater is increasingly contributing to the pollution of surface and underground water sources Currently, only 60% of hospitals have wastewater treatment facilities, with a mere 18% functioning at full capacity Many hospitals either lack treatment stations or fail to meet required standards Additionally, wastewater from urban factories is often untreated and discharged directly into public sewer systems, exacerbating the pollution problem.
During the rainy season, approximately 30% of urban areas experience flooding due to heavy rains, with flood durations ranging from one to twelve hours Many regions previously unaffected by floods are now at risk Key factors contributing to this issue include illegal connections to drainage systems, an increase in impermeable surfaces, high population density with extensive housing and road networks, and the uncontrolled disposal of waste in drainage systems.
1.4.3 The Organizations of Urban Drainage Services in Vietnam
In Vietnam's urban areas, most drainage companies handle both operations and management Currently, only four companies specialize exclusively in drainage services, located in Hanoi, Ho Chi Minh City, Hai Phong, and Ba Ria Vung Tau.
A total of 32 water supply companies also manage drainage services, while 36 urban infrastructure firms offer sewerage services alongside additional functions, including solid waste collection, street management, park maintenance, lighting, and funeral services.
Companies that manage water drainage systems are tasked with dredging and repairing sewers, operating drainage pumping stations, and maintaining canals and ditches Additionally, many urban drainage companies are expanding their services to include pipeline construction, sewer pipe production, and the emptying of household septic tanks.
1.4.4 Financial Aspects of Urban Drainage Companies
Like many developing countries, drainage companies face significant challenges due to insufficient funding for operation and maintenance Typically reliant on provincial or city budgets, these companies only receive 50-70% of the necessary financial support for their activities As a result, drainage services are effectively delivered in only half of urban areas, and essential maintenance tasks, such as sewer dredging, are often inadequately performed In practice, these maintenance activities are primarily carried out just before the rainy season to mitigate flooding risks.
As a result, many canals and ditches are normally full of sediments Many covers of sewer systems are missing, and broken pipelines are not replaced (Trinh, 2007) .
To support urban drainage companies financially, the government implemented Decree 67/2003 regarding the environmental protection fee and Decree 88/2007 concerning the wastewater discharge fee Decree 88/2007 outlines the fee structure for households discharging wastewater directly into the environment as well as those connected to the public sewer system Households discharging wastewater directly are subject to the fees established in Decree 67/2003, with all collected fees allocated to local budgets for environmental protection and sewer maintenance activities, as specified in Decree 26/2010 In contrast, households connected to the public sewer system pay a discharge fee incorporated into their water pricing, which is determined by the volume and concentration of their wastewater The revenue generated from these wastewater discharge fees is utilized for the operation and maintenance of sewer systems.
In November 2009, the Prime Minister approved decision 1930/QĐ-TTg, outlining urban development goals until 2025 with a vision for 2050 By 2050, all major towns (class IV and above) are expected to have comprehensive drainage systems for stormwater and wastewater treatment, while smaller towns (class V) and craft villages will utilize centralized or decentralized treatment stations This initiative aims to eliminate urban flooding and ensure that wastewater is treated before being released into the environment Additionally, the plan specifies detailed tasks for stormwater management, sewer operation and maintenance, and wastewater treatment in urban areas, craft villages, hospitals, and industrial zones for the years 2015, 2020, and 2025.
Fundamentals of Benchmarking
The term "benchmarking" has several theories regarding its origin One theory suggests it derives from a British term that refers to a reference point in terrain for comparison (Frứydis et al., 2005) Another theory posits that it originated in the fishing industry, where fish were placed on a bench and measured with a knife, allowing subsequent catches to be compared against the marked length (Anderson & Petterson, 1996).
Benchmarking serves as a standard for comparison across various organizations According to the American Water Works Association, it is defined as a systematic approach to identify best practices, innovative ideas, and effective operating procedures that enhance performance By adopting these superior practices, organizations can significantly improve their own operational effectiveness.
Benchmarking is a continuous process of measuring and comparing a company's business processes with those of leading organizations This practice aims to gather insights that help identify and implement improvements, ensuring ongoing organizational growth and efficiency (Parena & Smeets, 2001; Bjorn Anderson & Petterson, 1996).
Benchmarking, introduced by Xerox in the late 1970s, initially focused on comparing operational performance against top competitors, moving beyond traditional financial metrics Today, it has evolved into a powerful tool across various industries aimed at learning from the best to enhance performance The primary objectives of benchmarking include achieving improvements by studying superior practices, gaining insights into business processes, and fostering an urgent need for change to meet evolving customer demands.
(4) to develop strategic and operational goals and (5) to encourage creative thinking (Anderson
2.1.2 Types and Elements of Benchmarking
Benchmarking can be classified according to the comparison criteria and the entities involved There are three primary types of benchmarking based on the object of comparison: performance benchmarking, which assesses the effectiveness of outcomes; process benchmarking, focused on evaluating operational procedures; and strategic benchmarking, which examines overall strategies and competitive positioning (Anderson & Petterson, 1996).
As considering whom benchmarking compare against or the level of benchmarking, it can be classified into four types: (1) internal benchmarking, (2) competitive benchmarking, (3) functional benchmarking, (4) generic benchmarking (Anderson & Petterson, 1996).
All these kinds of benchmarking will be referred briefly in this section.
Performance benchmarking involves comparing key performance metrics, including reliability, quality, speed, and other characteristics of products or services This process aims to assess a company's performance in relation to its competitors, providing insights into its strengths and areas for improvement.
Process benchmarking is essential for identifying gaps in performance by not only focusing on outcomes like learning, adaptation, and improvement but also analyzing the underlying causes This method examines the intricacies of processes, their functionality, and the technologies employed, ensuring a comprehensive understanding of how to enhance efficiency and effectiveness in operations.
Strategic benchmarking looks for the strategic planning and positioning of a company that makes them succeed The results of strategic benchmarking are long-term (Lankford,
Internal benchmarking involves comparing various departments, units, or countries within the same organization to evaluate their performance Typically utilized in large corporations, this process allows for the identification of best practices by analyzing which units operate more efficiently The key advantage of internal benchmarking lies in its ability to easily define comparable processes and gather standardized data, facilitating the transfer of effective practices across the organization for overall improvement (Anderson & Petterson, 1996).
Competitive benchmarking is challenging due to the inherent difficulty in sharing information among competitors This approach involves assessing an organization's performance, products, and services specifically against those of its direct rivals within the same industry Effective competitive benchmarking necessitates thorough research and a concentrated focus on key competitors rather than the entire market.
Functional benchmarking is the comparison about a specific company function (e.g. maintenance) against that function in other company, a non competitor one This type of benchmarking is relatively easy to implement (Barends, 2004)
Generic benchmarking involves identifying companies from unrelated industries that execute similar processes to exchange information This approach offers significant potential for discovering new technologies or practices that can drive innovation and breakthroughs.
Benchmarking is an ongoing process that involves several key steps As illustrated in Figure 2.1, there are five primary stages in the benchmarking process, detailing the sequence in which they should be executed These step descriptions are adapted from the work of Anderson & Petterson, 1996.
Figure 2.1 Main steps of a benchmarking process (Source: Anderson & Petterson, 1996)
Effective planning is crucial in the benchmarking process, accounting for approximately 50% of the entire effort Key activities in this phase involve selecting the process to benchmark, assembling a dedicated benchmarking team, thoroughly understanding and documenting the process in question, and establishing relevant performance measures to evaluate success.
The search phase involves identifying suitable benchmarking partners by first establishing a set of criteria that these partners must meet Next, organizations known for their superior performance in the targeted process are researched After compiling a list of potential partners, the most qualified candidates are selected Finally, the last step in this phase is to invite these chosen organizations to participate in the benchmarking study.
Observe The purpose of observing step is to understand the benchmarking partners.
This step involves three key tasks: assessing information requirements, selecting data collection methods, and gathering information through observation and inquiry During the observation phase, data should be collected at three levels: first, the performance level, which evaluates how the partner compares to others; second, the methods and practices that facilitate achieving these performance levels; and third, the enablers that support the execution of processes according to the identified practices or methods.
In the analysis phase, data and information are gathered and examined to identify performance discrepancies between one's own processes and those of partners, as well as to uncover the underlying causes of these gaps.
International Benchmarking System in Water Industry
2.2.1 Benchmarking of large Municipal Wastewater Treatment Plants in Austria
The Austrian benchmarking system for wastewater treatment plants, developed between 1999 and 2004, has analyzed around 100 facilities serving populations from 2,000 to 1 million (EWA&DWA workshop report, 2009) Its primary goal is to establish process indicators that identify best practices and benchmarks By comparing a wastewater treatment plant's performance against these benchmarks, opportunities for cost reduction and optimization can be identified (Lindtner et al., 2008).
The article outlines four primary processes and two supporting processes, as illustrated in figure 2.2 Each primary process is further segmented into sub-processes, with all pertinent expenses, including annual total costs and operational and maintenance costs, systematically categorized.
Figure 2.2 Extended process model for wastewater treatment plants above 100,000 PE
To establish comparable process indicators, treatment plants were categorized based on their capacity ranges Benchmark plants are identified as those with the lowest operational costs while adhering to specific criteria: they must meet Austrian emission standards for effluent quality, have verified data through mass balance or other reliable methods, and exhibit typical characteristics of municipal wastewater without significant industrial influence.
The benchmarking process consists of three key steps: data acquisition, data processing, and experience exchange, primarily facilitated through internet communication (Report of EWA&DWA workshop, 2009) It involves two categories of data: operating data, which is updated annually, and conservative data, such as design capacity and tank volume, which only changes during upgrades The annual update of operating data is essential for benchmarking, while conservative data is modified only when necessary (Lindtner et al.).
Data quality assessment involves conducting plausibility checks to ensure that financial data falls within a feasible range Variance analysis is utilized to compare current data with previous year values, enhancing the accuracy of the information (Report of EWA&DWA workshop, 2009) Experience exchange is facilitated through individual consultations and workshops, where benchmarking experts meet with plant managers to address data quality issues and refine the final report Following these discussions, corrected or improved data is incorporated into the final report Workshops are organized for benchmarking participants to foster learning from best practices (Lindtner et al., 2008).
Figure 2.3 Methodology for the development of process performance indicators
(Source: Report of EWA&DWA workshop, 2009)
Benchmarking studies of wastewater treatment plants reveal that the annual total costs range from €26 for larger facilities to €71 for smaller ones, based on a standard of 110 g COD per person equivalent per day (PE/day) Additionally, the operating costs typically fall between €10 and €22 per PE per year.
€/PE/a, where mechanical-biological wastewater treatment account for 45% and the rest 55% is for additional sludge treatment and disposal (Lindtner, et al., 2004)
Initiated in 1997, the Canadian National Water and Wastewater Benchmarking Initiatives began with a focus on the wastewater sector across four cities By 2001, the project expanded to include the water supply sector, currently encompassing 42 facilities from both sectors (Koelbl, 2009).
Since 2001, process benchmarking activities have been conducted alongside corporate benchmarking, led by various task forces comprised of participant members These task forces focus on identifying best practice sources, such as methodologies from participants and the International Water Association (IWA) Their responsibilities include developing action plans based on these best practices, fostering networks among experts and participants, and piloting implementations in select facilities to refine the best practices for broader application (Koelbl, 2009).
Current process benchmarking projects are carried on these following topics: (1) water loss management, (2) maintenance planning (collection, distribution, and drainage), (3) complex facilities maintenance planning, (4) sustainable funding through asset management,
(5) wastewater treatment plant optimization, (6) energy management, (7) inflow and infiltration, (8) succession planning, (9) attendance management, (10) storm-water management (Koelbl,
2.2.3 North European Benchmarking Co-operation
Established in 2004 by Scandinavian and Dutch national water associations, the North European Benchmarking Co-operation (NEBC) initiated its first international water benchmarking pilot scheme in 2006 By the end of 2007, ten European countries had participated in this benchmarking initiative Utilizing the Performance Indicators (PIs) system from the International Water Association (IWA), NEBC developed a three-level benchmarking model to compare facilities at various levels The organization emphasizes five key performance areas: water quality, reliability, service quality, sustainability, and finance and efficiency.
NEBC's benchmarking program encompasses both the water and wastewater sectors In its initial pilot in 2006, NEBC adopted the Netherlands benchmarking methodology for drinking water; however, participants found it overly extensive and complicated for first-time users Consequently, a new methodology was developed for the second pilot scheme, based on the IWA Performance Indicators (PIs) system This benchmarking model features three participation levels: basic, metric, and advanced, allowing smaller or less experienced facilities to engage at a level appropriate for their developmental stage.
Figure 2.4 NEBC’s benchmarking model (Source: Dane & Schmitz, 2008)
NEBC’s benchmarking process involves seven key phases: the preparation phase, where new participants receive essential information; the data collection phase, conducted online with support from NEBC coordinators; the analysis phase, where submitted data is reviewed; the reporting phase, which provides a report highlighting key performance indicators (PIs) to assess facility performance and identify gaps; the best practice phase, where results are discussed, best practices are recognized, and action plans are formulated; the evaluation phase, which involves participants and coordinators assessing areas for improvement; and finally, the closing down phase, marking the end of the current benchmarking cycle and the start of a new one (Dane & Schmitz, 2008).
NEBC’s second international benchmarking pilot scheme was completed in April 2008,got positive results and feedback from participants and NEBC intend to proceed with the international benchmarking activities (Dane & Schmitz, 2008).
2.2.4 Benchmarking for Wastewater Services in Germany
In 1996-1997, Germany became the first country to adopt the benchmarking method in wastewater services Similar to practices in other nations, the success of benchmarking in Germany relies on two key factors: voluntary participation and the confidential management of information (Koelbl, 2009).
In 2005, six prominent German water industry associations, including ATT, BDEW, DBVW, DVGW, DWA, and VKU, established a benchmarking agreement aimed at enhancing the water sector This agreement outlines the methodologies for benchmarking, its objectives, data management, and public reporting of results While initial reports primarily featured statistical data, guidelines for benchmarking in water and wastewater enterprises were developed to assist small and medium-sized plants Additionally, a public document presenting key performance indicators was released to ensure compatibility in benchmarking practices across Germany (Report of EWA&DWA workshop, 2009).
There are more than 27 benchmarking projects being currently carried out in Germany.
Benchmarking activities in Germany focus on key aspects such as supply safety, quality, customer service, sustainability, and efficiency (Koelbl, 2009) Several federal states, including Bavaria, Baden-Württemberg, Rhineland-Palatinate, North Rhine-Westphalia, Lower Saxony, and Mecklenburg-Western Pomerania, have completed their first cycle of benchmarking projects, with final reports now available Meanwhile, benchmarking efforts continue in Hessen, Thuringia, Schleswig-Holstein, Bremen, Hamburg, and Berlin (Report of EWA&DWA workshop, 2009).
Like Austria, data collection is conducted using an online tool, with centralized organization for quality testing This approach minimizes participant effort and enhances engagement in benchmarking projects.
Process Benchmarking in Wastewater Sector
Though there are many process benchmarking projects in different countries around the world, a worldwide acceptation of definition and steps of this type of benchmarking has not been defined (Koelbl, 2009).
Process benchmarking, as defined by Joerg Koelbl, is a management methodology aimed at comparing and optimizing performance in process operations It relies on a clearly defined process structure that divides the overall process into sub-processes and individual tasks To facilitate quantitative comparisons, it is essential to calculate performance indicators for both the overall process and its components Additionally, documenting the process operation in writing enhances understanding, while also considering both economic factors and the quality of the process operation.
Process benchmarking relies heavily on the sharing of experiences, ideally through workshops Following thorough cause analyses and the implementation of corrective measures, the effectiveness of optimization efforts is assessed through a new performance comparison (Koelbl, 2009).
2.3.2 The Objectives of Process Benchmarking
Process benchmarking focus on detail optimization potentials therefore it is required to gain a basis of process operation To achieve this aim, process benchmarking should answer these following questions:
- How are the overall process and sub-processes operated?
- How much do the main process and sub-processes cost?
- What is the working time of the main process and sub-processes?
- Are the defined quality criteria complied?
- How do the other facilities perform and why are there differences?
Water utilities can achieve significant operational benefits through process benchmarking by either reducing costs while maintaining the same level of process quality or enhancing process quality without increasing costs.
The macro economic benefits of increasing efficiency and quality that can be seen from water supply sector.
To achieve high-quality process benchmarking, it is essential to establish a clear hierarchical process structure Each process must have well-defined input and output data to accurately delineate the main processes and their corresponding sub-processes This crucial step is known as process mapping.
To effectively benchmark both technical and economic factors, it is essential to establish quality criteria for each process and sub-process Additionally, understanding the operational framework and variations is crucial for accurate analysis (Koelbl, 2009).
An existing cost accounting system often fails to meet the necessary standards for collecting costs related to process benchmarking To address this, it is essential to develop a suitable cost allocation system This involves gathering data at the sub-process level and managing the total costs associated with the overall process effectively.
After setting process performance indicators a performance comparison is implemented between groups of participants.
The results of the comparison should be discussed internally before introducing to the step of exchanging experience and learning
Figure 2.5 Procedure of process benchmarking
To achieve the goal of becoming "best in class," organizations should prioritize knowledge exchange through workshops that facilitate the discussion and analysis of comparative results Identifying and adopting best practices is essential for enhancing process operations and driving continuous improvement.
The IWA manual on best practices for process benchmarking in the water sector highlights the effectiveness of a holistic approach, exemplified by the Netherlands and Scandinavian countries This methodology involves a comprehensive analysis of all processes within a water facility, starting from water extraction and extending to the final sales to customers.
Selective process benchmarking, utilized in regions like Australia and Bavaria, Germany, focuses on analyzing specific processes rather than evaluating all processes comprehensively A comparison of the holistic and selective approaches is illustrated in Table 2.1.
Table 2.1 Holistic approach versus selective approach in process benchmarking a
- Analyze all processes in the operation of a water facility
- Practices in the Netherlands and
- Advantage: closed cost allocation system
- Disadvantage: highly aggregated sequences of single tasks; coarse division
- Analyze the selected processes in the operation
- Practices in Australia, Bavaria in Germany
- Advantage: simple cost allocation system; more detailed analyses
- Disadvantage: no closed cost allocation system a: From Koelbl , 2009