https://orcid.org/0000-0001-8797-2010
Abstract
The aim of this work is to provide the necessary steps to acquire the total cost of water at industrial facilities. Therefore, the research was developed in three parts: literature review to identify the available tools related to water management; a case study in the context of the dairy industry; and an analysis and discussion of results achieved. Water applications for process and utility end-users in the manufacturing context require pre- and post-treatment – these are interconnected assets that increase the cost of water, and introduce system inefficiencies, thus, they represent a challenge faced by companies and energy/utility managers. A meta-analysis approach was used to examine data from several independent studies of water management, in order to determine overall trends. The sources utilized during the study were water-related scientific publications, Master theses, books, companies, and standards’ websites. The results of the study highlight that auditing can be used to investigate water flows within productive processes entirely, as well as within individual process units and operations. The present study incorporates water-related thinking about supply and demand costs, opportunities, and strategies, promoting energy systems thinking and providing an internationally replicable solution to calculate the true cost of water.
HIGHLIGHTS
Water used for process and utility applications in the manufacturing context requires pre- and post-treatment. Moreover, further energy input is also required from utility systems such as cooling towers, chillers, and boilers to meet temperature requirements. This work provides an understanding of the necessary steps in order to acquire the total cost of water at industrial facilities.
INTRODUCTION
Understanding the necessity of knowledge of the total cost of water within manufacturing comes first with the fact that the increase in the world's population and economy is pushing the necessity for more resources in all sectors, including industry, which in accordance with the last CDP report (CDP 2018), represents 19% of global water consumption. In accordance with the forecast made in the UN World Water Development Report (ONU 2020), freshwater resources will decrease by 40% by 2030, whereas water demand will increase by 20–30% by 2050. Analysing water consumption per geographical region, Del Rio Infante & Gil-Alana (2022) describes the OECD nations consume 20–25%, the so-called BRICS (Brazil, Russia, India, China, and South Africa) countries consume 45% and the rest represent between 30 and 33%.
Water used in industrial processes and utility applications require further energy input from cooling towers, chillers, and boilers to meet temperature requirements (Agana et al. 2013). In addition, water treatment may be required pre and post the processes. These factors are interconnected and increase the real cost of water while introducing system inefficiencies.
Demonstrating the incorporation of water-related thinking in regard to supply and demand costs, opportunities, and strategies, some water initiatives have been created since 2010. Global organizations like Nestlé (Vittel Water), the Coca-Cola Company, and PepsiCo have already implemented strong water stewardship policies within their operations (Sustainable Brands 2016; Khalamayzer 2017) and are on the AWS (Alliance for Water Stewardship) certification list. It has not only allowed these companies to gain good publicity, but also has allowed them to navigate all of the potential regulatory, reputational, and physical water risks in a manner that promotes improved social, economic, and environmental performance for the business (EPA 2018).
A large variety of options are available for improving the efficiency of water use, aiming at both reducing future water shortages and preventing the contamination of water bodies (Boysen et al. 2020; Piadeh et al. 2022). These strategies are commonly called regeneration, reuse, and recycling practices (Gomes et al. 2007). In other to identify potential energy savings, an audit can be performed to understand and characterize the water system. A water diagram can be generated using gathered data, which presents a steady state snapshot of water use in terms of inputs and outputs. Critical processes can then be identified, and cases can be made for the application of conservation strategies, optimization software, and further investment in technology (Agana et al. 2013). Conservation philosophies can be applied, such as minimizing the liquid discharge where possible (Barrington & Ho 2014). Pinch analysis tools can be implemented to match process sources with sinks (Abdulaziz et al. 2005), thereby reducing wastewater discharge (Wan Alwi et al. 2008). This method can be applied graphically (Feng et al. 2007), for simple cases with few inputs, or using available software (Etienne et al. 2008). Therefore, a diversity of methodologies and tools to improve water management and efficiency of water have been available in the industrial context and should be selected according to each particular case.
Thus, seeking to identify the necessary steps to implement water management in a manufacturing facility, this research was developed in three parts: literature review to identify the available tools related to water management for acquiring the true cost of water; a case study in the context of a dairy industry; and analysis and discussion of results achieved.
WATER MANAGEMENT
Water management can be applied in different ways depending on the industry objective. To know the true cost of water, some background information in relation to data gathering is necessary.
Industrial water management
Water scarcity is creating new business challenges even in locations with ample water supplies, as in Ireland, where the case study where the methodology of this research was applied. Global industrialization is increasing water demand: nowadays water use in industries represents 19% of global water consumption (CDP 2018). In accordance with the forecast made in the UN World Water Development Report (ONU 2020), freshwater resources will decrease by 40% by 2030. Reporting data from UNESCO, Dworak et al. (2007) affirm the water volume used by industries worldwide was 752 km3/year in 1995, and the estimation for 2025 would be 1.170 km3/year. Tendencies also show large differences between regions and countries in relation to share industrial sector in total water abstraction.
Focused on effectiveness, water management might evaluate not only optimization values but also practical, behavioural, and communication issues to allow a holistic approach (Barrington & Ho 2013). Nowadays freshwater scarcity, water price fluctuations, and/or restricted discharge limitations have been forcing process industries to develop water management strategies to minimize unfavourable water risks (Mueller et al. 2015). According to the World Business Council for Sustainable Development, water risks can be grouped into five categories (Christ & Burritt 2017): financial (restriction to capital, higher loan rates, and insurance premiums); operational (increased production costs and disruptions); product (loss of market share due to customer’s concern and preference); reputational (potential for community conflict and loss of license to operate); regulatory (chance of new fees, regulations, fines).
In order to avoid and/or mitigate these risks, standards come as ‘a set of guidelines that outlines expected actions or performance’ (WWF 2015). In this sense, international water stewardship standards have been created aiming at improving the level of performance of an industry: its water efficiency, water quality, environmental impact, and internal governance of individual production sites, ensuring sustainable water management (EPA 2018). Like most standards, water stewardship certification is under constant evolution as a consequence of the ever-changing needs and challenges of the water sector.
Exploring further key stages of water management in a manufacturing facility, water system auditing is the natural place to start. Auditing can be used to investigate water flows within holistic productive processes, as well as within individual process units and operations. As an approach, this technique quantifies water usage and quality while allowing greater insights into the behavioural aspects of water management (Seneviratne 2007). Therefore, an understanding of the water baseline consumption is possible, as well as the true costs at points of use, identification of quick wins and conservation opportunities, and identification of potential leaks for investigation thus leading to the development of an optimum site wide metering strategy (EPA 2018).
Water auditing can determine whether significant losses are occurring within a predefined system boundary (Barrington & Ho 2013). In this auditing context, VSM (based on LEAN philosophy) could be applied as a tool, its main objective within organizations would be the detection of wastes in the production flow through VSM (Oliveira et al. 2017). Even though some losses are unavoidable, by audit it can be determined what proportion of water loss they are willing to accept (Barrington & Ho 2013).
Key goals for the industrial sectors consist of both locating and quantifying the water inefficiencies through its processes, and selecting optimum conditions of design and operation to reduce losses and minimize impacts. Overall, enhancements in the industry can be focused on installations, process steps, and good practices of workers (Carrasquer et al. 2017). According to Foo (2009), pinch analysis appears as an important optimization technique, making possible the application of reuse, recycle, and regeneration: reuse (when the effluent from a water-using operation is sent to other operations and does not re-enter operations where it was emitted); recycle (in opposite to the reuse concept, recycle is when effluent when re-enter the operations where it is generated); regeneration (the effluent is partially treated by water a purification unit before reuse or recycle takes place). Independent of the technique chosen, it is important to keep in mind, as much as possible, the concept of zero-wastewater discharge (ZWD) or zero-liquid discharge (ZLD) and practice design scenarios optimization (Shenoy & Shenoy 2015).
The control of water losses has been an activity associated with water distribution since some of the earliest systems were built – the aqueducts. In the 1st century AD, Romans were aware that a certain proportion of the water put into their aqueducts was not reaching its intended destination of supply. Nowadays, centuries after, engineers and technicians are still struggling with the same problem, however, now there is a variety of equipment and tools have been developed to tackle the problem of precisely and efficiently locating and measuring non-visible leaks (Bergoglio & Mari 2012).
When considering a sustainable water management strategy, financing is a delicate point, as water projects, in general, require long-term investments, have longer payback periods, and are perceived as risky by commercial lenders (Reif & Alhalabi 2015). Green or environmental taxation, defined as the fiscal instrument whose tax base is a physical unit of something that has a proven, specific, negative impact on the environment, would include wastewater, abstraction, and waste charges (Berbel et al. 2019). The true cost of water as a smart indicator includes but also goes beyond the concept of green taxation, as it includes all internal financial analysis within an industrial facility, including extraction, treatment, pumping, storage, purification, and disposal – that is not only related to the use of water itself but all factors and resources necessary to make it usable and correctly discharged. In this sense, there is a clear contribution to water foot-printing, system/regulation compliance, product pricing strategy, and facility benchmarking for intelligent manufacturing as well (Walsh et al. 2017).
Overall, initiatives in Europe showed that the use of indicators is essential in the development of policies for water resource management, and also for the optimization of production processes, products, and services (Carrasquer et al. 2017). However, it should be created in a way that is systemic, hierarchical, logical, and communicable (Tahir & Darton 2010), engaged with adequate management tools to provide the best results to the manufacturing case scenario.
Assessment of the water management tools
With the purpose of identifying water management tools that support the understanding of what steps to apply in order to acquire the total cost of water in manufacturing and industrial facilities, a literature review was conducted by building off the core of journal papers, Master theses, books, companies and standards' websites, all related to water relevant topics to this study.
The main key words utilized for findings were: industrial water, water management, water audit, cost of water, water technologies, water reuse, and water pinch (WP) analysis. Table 1 shows the main findings from the literature review process, separated into conceptual and implementation.
Water management methods
| METHODS | DESCRIPTION | SOURCE | |
|---|---|---|---|
| Conceptual | Water audit |
| Barrington & Ho (2013), Seneviratne (2007) |
| Water stewardship |
| AWS (2019), Christ & Burritt (2017), EPA (2018), EWS (2012), Khalamayzer (2017), Sustainable Brands (2016), WWF (2015) | |
| Water eco-efficiency indicators |
| Pinter et al. (2005), Bell & Morse (2008), Tahir & Darton (2010), Carrasquer et al. (2017) | |
| Implementation | Water mapping |
| American Water Works Association (2006), Barrington & Ho (2013), Matarazzo et. al (2019), Sturman et al. (2004), Tuan et al. (2016) |
| Leakage detection |
| Bergoglio & Mari (2012), Berst (2014), Leak Busting (2017), Przystalka (2018) | |
| Cost calculations |
| Walsh et al. (2017), Reif & Alhalabi (2015), Bhojwani et al. (2019) | |
| Pinch analysis |
| Carrasquer et al. (2017), Liu et al. (2007), Liu et al. (2009), Foo (2009), Bavar et al. (2018), Wang & Smith (1994), Castro et al. (1999), Dhole et al. (1996), Sorin & Bedard (1999), Hallale (2002), Prakash & Shenoy (2005), Foo et al. (2006), Almutlaq et al. (2005), Bandyopadhyay (2006), Ng et al. (2009), Deng et al. (2008), Liu et al. (2007) | |
| Water savings |
| Agana et al. (2013), Boysen (2020), Piadeh et al. (2022), Dworak et al. (2007), Gomes et al. (2007), Shenoy & Shenoy (2015), Staniskis (2010) | |
| METHODS | DESCRIPTION | SOURCE | |
|---|---|---|---|
| Conceptual | Water audit |
| Barrington & Ho (2013), Seneviratne (2007) |
| Water stewardship |
| AWS (2019), Christ & Burritt (2017), EPA (2018), EWS (2012), Khalamayzer (2017), Sustainable Brands (2016), WWF (2015) | |
| Water eco-efficiency indicators |
| Pinter et al. (2005), Bell & Morse (2008), Tahir & Darton (2010), Carrasquer et al. (2017) | |
| Implementation | Water mapping |
| American Water Works Association (2006), Barrington & Ho (2013), Matarazzo et. al (2019), Sturman et al. (2004), Tuan et al. (2016) |
| Leakage detection |
| Bergoglio & Mari (2012), Berst (2014), Leak Busting (2017), Przystalka (2018) | |
| Cost calculations |
| Walsh et al. (2017), Reif & Alhalabi (2015), Bhojwani et al. (2019) | |
| Pinch analysis |
| Carrasquer et al. (2017), Liu et al. (2007), Liu et al. (2009), Foo (2009), Bavar et al. (2018), Wang & Smith (1994), Castro et al. (1999), Dhole et al. (1996), Sorin & Bedard (1999), Hallale (2002), Prakash & Shenoy (2005), Foo et al. (2006), Almutlaq et al. (2005), Bandyopadhyay (2006), Ng et al. (2009), Deng et al. (2008), Liu et al. (2007) | |
| Water savings |
| Agana et al. (2013), Boysen (2020), Piadeh et al. (2022), Dworak et al. (2007), Gomes et al. (2007), Shenoy & Shenoy (2015), Staniskis (2010) | |
The process of selection and reading of the papers mentioned in Table 1, further refined regarding water management methods, allowed a critical analysis of conceptual and implementation methods highlighted. From the main findings, Water Stewardship demonstrates the incorporation of water-related thinking in regard to supply and demand costs, opportunities and strategies. There have been some water initiatives created since 2010. These initiatives work with a variety of scopes at different levels: product and process levels; site and corporate accounting; supply chain and catchment entities. Ireland has been recognized internationally by the adoption of other sustainability standards (especially in the sense of energy efficiency). Now, the Environmental Protection Agency (EPA) in Ireland – the environmental regulator – aims at establishing the country as a water-smart economy and enhancing the competitiveness of its industry on a global stage by adopting water stewardship best practices. Therefore, it was developed a national water stewardship policy with an associated awareness programme by key stakeholders. Such work should link to important standards: EWS (which committee is based in Brussels) and AWS (Edinburgh) to build on existing knowledge and standards globally (EPA 2018). AWS presents its content as a bit more extensive, however, both AWS and EWS present similar principles, as described by Table 2:
Standard principles
| EWS | AWS | ||
|---|---|---|---|
| 1 | Sustainable water abstraction | 1 | Good water quality |
| 2 | Good water status | 2 | Sustainable water balance |
| 3 | Protection of high conservation value areas | 3 | Healthy water-related areas |
| 4 | Transparent and equitable water governance | 4 | Good water governance |
| 5 | Water Sanitation and Hygiene (WASH) | ||
| EWS | AWS | ||
|---|---|---|---|
| 1 | Sustainable water abstraction | 1 | Good water quality |
| 2 | Good water status | 2 | Sustainable water balance |
| 3 | Protection of high conservation value areas | 3 | Healthy water-related areas |
| 4 | Transparent and equitable water governance | 4 | Good water governance |
| 5 | Water Sanitation and Hygiene (WASH) | ||
Authorship based on AWS (2019) and EWS (2012).
Water audit is the process of data collection by the site's data management system and field studies, which means: site knowledge, quantification of metered flows, unmetered flows (assumptions on the type and frequency of use), inspections and investigations of waste using processes and leaks, and conversations with engineers and operators (Barrington & Ho 2013). The processes related to the specific individual plant will bring information in regard to areas where water can be saved and the most appropriate strategy/range of actions to be put in place for reducing water demand and increasing industrial value added per unit of water consumed (Dworak 2007). In the sphere of evaluating sustainability, a common technique through corporations is to measure the performance by appropriate indicators (Pinter et al. 2005; Bell & Morse 2008), which is, as stated by Tahir & Darton (2010), a simple reflection of issues – water eco-efficiency indicators. Initiatives in Europe showed that the use of indicators is essential in the development of policies for water resource management, also for the optimization of production processes, products, and services (Carrasquer et al. 2017). However, it should be created in a way that is systemic, hierarchical, logical, and communicable (Tahir & Darton 2010). The most commonly developed framework that facilitates the reporting of sustainability performance of organizations, in certain companies the Global Reporting Initiative (GRI), a standard issued by the Global Sustainability Standards Board (GSSB) is used. Through the water section, GRI overall emphasizes the importance of reporting water withdrawal, discharge, and consumption.
In order to facilitate a water auditing, it is important to map a primary level of information related to water inputs and outputs based on current industry best practices (Sturman et al. 2004; American Water Works Association 2006; Barrington & Ho 2013; Tuan et al. 2016; Matarazzo et. al 2019), that would be the Water Mapping method. It can be translated into the conception of a mass-balance, based on principles of conservation of mass over time, which refers to the alteration of mass water from inflow to outflow water (without making any change in total mass water). The on-site water mapping activity can be divided into 5 main steps, in accordance with (Tuan et al. 2016): (1) System analysis: a good level of understanding of the water system is necessary, in terms of characterizing the most important categories, processes and components by reviewing accurate and up to date drawings, specifications and documentation. Moreover, having discussions with process owners and colleagues who have expertise with the water processes; (2) System description: mass fluxes representation and concentration of indicator elements are measured; (3) Data acquisition: interpretation and validation of fluxes; (4) Water balances, modelling and scenario building: development of scenarios and determination of monitoring points; (5) Interpretation: loading quantities, sustainable indicators and other assessment approaches will give us the results of water balance analysis study, making it possible next steps related to monitoring and cost analysis and water efficiency improvements.
It is well-known that leaks are a significant source of water loss (Berst 2014; Leak Busting 2017): however, it is such a surprise for many that the proportion of this loss in most cases is large. Irish Water, for example reported that between 2018-2020, the rate of leakage in Ireland was between 38-46% (Irish Water, 2022). Its most frequent origins are due to assembly errors, mechanical damages of pipes caused by overloads, fatigue, or normal wear and tear, material defects in parts of pipelines and corrosion (Przystalka 2018). Identification of leaks can be carried out with the following methods: in-pipe camera equipment; trace gas methods; dye testing; thermography (i.e., detecting altered thermal characteristics of the surrounding soil due to escaping water); ground penetrating radar. In this sense, Leakage detection would be another implementation method for Water Management. Every m3 of water used to generate a cost for industries. Even though some companies purchase water and wastewater treatment from municipal providers, there are always indirect costs spread throughout site operations. Water treatment costs have gone down significantly over the last few decades due to technological improvements which is providing a reduction in energy consumption, enhanced construction materials and better life spam of the systems (Bhojwani et al. 2019). The knowledge of the nature of all expenditures within all water systems within an industry requires a split into the following 5 differential groups: supply and distribution; pre-treatment; end-users; post-treatment; drain/disposal. WP analysis appears as an optimization method, figuring out the minimum freshwater demanded by the production processes (Liu et al. 2007; Liu et al. 2009). A considerable amount of work has been presented for water network synthesis using WP after the 90s. According to Bavar et al. (2018), WP analysis is used for systems in which water consumption is limited by a single contaminant, which in agro-industrial/food industry sector could be established in relation to organic matter. According to Carrasquer et al. (2017): (1) Brainstorming for the WP method would consist of the following: check outlet concentrations in which below reuse is possible; (2) Establish reuse flow priority (lowest to highest concentration of output; lower to higher pollution load); (3) Water reused is being used as supply; (4) Be aware of maximum pollutant concentration permissible. Mainly, WP has two work frameworks: flowrate targeting set in a minimum freshwater and wastewater flowrates (based on concentration and flowrate restrictions), and in this sense, the cases can be outlined as fixed load or fixed flow rate problems (this latter being more recently used – after the change by century 2000) (Foo 2009).
According to the European EPA, the challenge facing industry in relation to water savings is in some cases the demand for better quality products may purpose higher water requirements. Ireland, among other countries like Denmark and UK, demonstrated an increase in industrial water consumption during the 80 and 90s, due to the acceleration of its industrial development. Industries consider different water-saving strategies (Dworak et al. 2007) changes in production processes; reduction in wastage and leakages; recycling and reuse of water; changes in cooling technology; on-site rainwater harvesting; implementation of the classical water-saving devices considered for the household sector; certification provision, as it brings incentive to review water use and therefore identify potential water-saving strategies.
THE INDUSTRY CONTEXT
Once an understanding of the tools available for Water Management and their possible applications to assist the demystification of the true cost of water in a company, this study also considered the importance of the knowledge of the setting where these tools would be applied through a dairy industry case study. Overall for industries, as mentioned by Jagannath & Almansoori (2016), primary water functions can be itemized by: washing (water as a cleaning medium to equipment, rinsing and washing raw materials and products); separation (water as an agent in absorption, scrubbing and liquid–liquid extraction); product manufacturing (water as an ingredient); energy generation (water used in boilers to produce steam and power); cooling (for cooling the processes).
It is known that bio-refineries and food industries are among the group of highwater consuming industries (Weber & Saunders-Hogberg 2018), as the applications are not only based on general water use (washing, cooling, heating, etc), but also water is used as reactant in the process (Dworak et al. 2007; Bavar et al. 2018). Among food industries, Irish dairy's water consumption is significant in Europe, with the consumption figure exceeding 5 billion litres (O'Connor et al. 2018).
Food processing is the third largest industrial water user just after the refined petroleum, primary metals and chemical industries (Barbera & Gurnari 2018). Due to very stringent hygienic standards, water quality is important to ensure product quality and safety. Much attention is given to a good quality of intake water, as EU regulations state that ‘the competent authority is satisfied that the quality of the water cannot affect the wholesomeness of the food stuff in its finished form’ (Dworak et al. 2007).
The food industry is not only a significant water user, but also generates large quantities of wastewaters (Abdallh et al. 2016). The main characteristics that distinguish wastewaters from food industries in comparison to municipal or other industrial wastewaters is that they are biodegradable and do not contain toxic chemicals (Emara et al. 2017). Apart from significant values of BOD and COD, there are also high concentrations of dissolved (DS) and/or suspended solids (SS) (including oils, fats, grease), nutrients such as nitrogen (N, including ammonia) and phosphorous (P), minerals (e.g., salts), and varying pH values (Tekerlekopoulou et al. 2020). In addition, food industry wastewater production shows wide regional and seasonal variations (Onet 2010). Technologies to treat food industry wastewater include physicochemical systems, biological systems (anaerobic, aerobic or microalgal based), constructed wetlands, electrochemical methods, membrane bioreactors, advanced oxidation processes or hybrid systems including two or more of the above-mentioned methods (Abdallh et al. 2016; De Gisi & Notarnicola 2017).
Previously, wastewater treatment processes were applied for only safe disposal of wastewater. However, nowadays, they have appeared as a technology-based opportunity for best practices in terms of both sustainability and cost reduction (Yaqub & Lee 2019). It has been commonly mentioned as ZLD, attracting interest as a valuable water management solution for industrial wastewater by maximizing water recycling and minimizing wastewater volumes (Mays 2007). In the ZLD technique, a closed water cycle is used so that no water is discharged from a system if there is a possibility of it being reused after appropriate treatment. Advanced water treatment technologies mentioned more frequently are the ones based on thermal systems, RO and RO-incorporated thermal systems (Yaqub & Lee 2019).
The true cost of water demystification was applied in the context of the dairy industry case study, with Eco-systems indicators illustrating a based-stewardship program application. The efficiency of the whole process extracted from GRI recommendations, but also on the approach of sustainability in which Environment, Economy and Society are interconnected (Tahir & Darton 2010). Both methods allowed metric calculations to answer the question if the water resource is being used efficiently on site, and how its use can affect future generations.
In this sense, water auditing is seen as an essential tool to determine appropriate measures for water conservation. When the water mapping exercise is complete, an analysis of the water distribution system provides the insights on where the leaks are, and the leakage percentage on the site. Moreover, a clear picture on water usage is checked, and the true cost of water is established, providing clarity for future business cases for water-saving initiatives.
Considering the preparation of the industrial facility for the audit, the necessary steps were organized as: having a documented process to identify and document the attributes; maps to identify the location, scale and physical attributes; tool for quantification (numerically) documenting the attributes; monitoring and implementing the plan and related commitments; making a document available to relevant stakeholders, allowing publicity.
As a matter of evaluating the system, indicators should be stablished in a holistic way. According to GRI and other Literature on water eco-system indicators (Tahir & Darton 2010; Carrasquer et al. 2017), the list in Table 3 below was composed. The nomenclature SWU means ‘Significant Water Users’, which is related to the end-users within the industrial facility: process, utilities, and domestic.
Water eco-efficiency indicators
| Indicators | Calculation | |
|---|---|---|
| 1 | Water withdrawal per water consumed (Leak percentage) |  |
| 2 | Total volume consumed per each facility process user (SWU) | m3 m3/h m3/ton |
| 3 | Total volume discharged per each facility process user (SWU) | m3 m3/h m3/ton |
| 4 | Non-compliance of water quality production |  |
| 5 | Non-compliance of water quality discharge |  |
| 6 | Water cost | €/m3 |
| Indicators | Calculation | |
|---|---|---|
| 1 | Water withdrawal per water consumed (Leak percentage) | |
| 2 | Total volume consumed per each facility process user (SWU) | m3 m3/h m3/ton |
| 3 | Total volume discharged per each facility process user (SWU) | m3 m3/h m3/ton |
| 4 | Non-compliance of water quality production | |
| 5 | Non-compliance of water quality discharge | |
| 6 | Water cost | €/m3 |
Authorship based on Tahir & Darton (2010); Carrasquer et al. (2017).
Based on findings reported by Bhojwani et al. (2019), Table 4 demonstrates a matrix representing a relationship of the different water systems in an industrial facility and the capital and operating costs each one contributes. Moreover, there are also unified costs the facility incurs regarding the whole system, such as land use, insurance, water risk factor, legal, fiscal, and administrative fees.
Water systems’ cost matrix
| Costs | ||
|---|---|---|
| Capital | Operating | |
| Supply and distribution | Cost of pipes, pump stations, licensing and establishment of distribution facilities. | Servicing pumps, inspecting for leaks, cracks and replacing electrical and moving components, external lab analysis. |
| Pre-treatment/end-users/post-treatment | Investment for the equipment, piping, valves, site preparation, concentrate discharge systems, auxiliary equipment such as water storage, emergency response systems, engineering. | Labor, energy costs (thermal and electrical), chemicals, maintenance and spare parts replacement, sampling. |
| Drain/Disposal | NA | Weekly disposal costs, licensing. |
| Costs | ||
|---|---|---|
| Capital | Operating | |
| Supply and distribution | Cost of pipes, pump stations, licensing and establishment of distribution facilities. | Servicing pumps, inspecting for leaks, cracks and replacing electrical and moving components, external lab analysis. |
| Pre-treatment/end-users/post-treatment | Investment for the equipment, piping, valves, site preparation, concentrate discharge systems, auxiliary equipment such as water storage, emergency response systems, engineering. | Labor, energy costs (thermal and electrical), chemicals, maintenance and spare parts replacement, sampling. |
| Drain/Disposal | NA | Weekly disposal costs, licensing. |
Authorship based on Bhojwani et al. (2019).
According to the reality at the case study industrial facility in terms of water use, to obtain the true cost of water, it means, the €/m3 the company spends in a yearly basis, each water stage unit should be treated separately, and the Unit Product Cost (UPC), would represent the sum of the capital depreciated over the plant life and operating cost per m3 water treated, could be calculated.
It is important to note that depreciation is usually taken as 20 years without salvage value and the plant availability is the number of days in a year that the unit operates (Bhojwani et al. 2019). Moreover, for the case of Drain/Disposal group, UPC will be related only to operating cost.
RESULTS AND DISCUSSION
Water management procedure application in the industry context (Authorship).
Relationships between factors when the proposed steps to demystify the true cost of water found in this research was applied in the manufacturing case study (Authorship).
Relationships between factors when the proposed steps to demystify the true cost of water found in this research was applied in the manufacturing case study (Authorship).
As results of the water management literature review and the case study, it is highlighted a need for starting the investigation of the true cost of water by following a logical sequence in which a water audit would be applied, based on water stewardship principles.
The case study in which this procedure was applied is a self-sustainable system, in which pre and post water treatment comply with the single uses specifications. The dairy industry is challenging in terms of water usage, as water is not only part of its final product, but also part of the technology to provide the productive right conditions environment. Taking that as a system, the application of water management tools took into account the initial pumping (supply and distribution), initial treatment (water treatment), end-users inside the manufacturing process of the product (water as ingredient), its conversion (hot/cold water), predial domestic infra-structure required, final treatment (wastewater treatment plant) and final water discharge (drains).
According to the results found from this study, a strategy could be formulated organizing the procedure for discovering the true cost of water inside an industry facility and further opportunities this data will bring for site improvements. Therefore, the steps are: (1) Stablishing a stewardship standard to guide water management to be implemented; (2) Water audit based on the standard to data gathering and gap analysis formulation (2.1. Water Mapping, 2.2. Checking costs, 2.3. Checking leakage percentage losses inside the company, 2.4. Attributing water information to a value, 2.5. Evaluating opportunities for water management improvement); (3) Monitoring the whole system constantly, analysing data through eco-efficiency indicators.
Costs calculations will depend on capital and operational costs of the factory. They can be then illustrated by Sankey fluxes to show in each, €/m3. Analysis such as leakage detection and pinch analysis will identify future improvement possibilities that can reduce the on-site true cost of water. Eco-efficiency indicators would be a tool for constant monitoring and control of not only environmental water metrics, but also for water costs.
CONCLUSION
As a result of the literature review and case analysis, this study presented a structured approach which walks through the water auditing process, aiming at a state-of-art procedure to acquire a holistic framework to implement a water management system capable of demystify the true cost of water within an industrial facility. The audit process should be organized in a way that the indicators established will be in line with water stewardship standards, and a water map that can be further interrogated based on that. Therefore, allowing a better understanding of the water baseline consumption on site, as well as the true costs at points of use, identification of leaks requiring investigation and the development of an optimum site wide metering strategy, closuring the full research with the identification of quick wins in relation to reuse, recycling and new conservation opportunities, aiming at a Circular water and ZLD conception application.
DATA AVAILABILITY STATEMENT
All relevant data are included in the paper or its Supplementary Information.
CONFLICT OF INTEREST
The authors declare there is no conflict.
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