- What are WEST and WWEST?
- What knowledge will I gain from using WEST and WWEST?
- Who should use WEST and WWEST?
- What is the methodological basis for WEST and WWEST?
- What does WEST look like?
- What does WWEST look like?
- How can I get copies of the tools for my own use?
- WEST Update Log
- WWEST Update Log
What are WEST and WWEST?
The Water-Energy Sustainability Tool (WEST) is an MS Excel-based tool which can determine some of the environmental effects of water system infrastructure and operation. Figure 1 shows the components of a water system which can be included in a WEST analysis. The Wastewater-Energy Sustainability Tool (WWEST) is a similar tool which evaluates the effects of wastewater infrastructure and operation. WWEST evaluates the collection, treatment (both liquid and solids), and discharge components.
Figure 1: Water System Components [Stokes 2004]
WEST and WWEST incorporate life-cycle assessment (LCA), a proven methodology for systematically quantifying cradle-to-grave material, water, and energy inputs and environmental outputs (e.g., air emissions, solid waste, polluted water). WEST can evaluate up to five sources of water at once (e.g., groundwater, reservoir, importation, desalination, and recycling) or five design scenarios (i.e., alternative treatment processes or pipeline configurations), and can analyze components of the larger system (e.g., a new pipeline or treatment plant). WWEST evaluates each scenario for wastewater treatment separately. The tools require user input for the construction and maintenance phases, equipment use, and electricity consumption for a water supply or wastewater system. Based on the input, WEST and WWEST provide outputs for life-cycle air emissions. Environmental effects calculated include:
- Energy consumption
- Greenhouse gas emissions
- NOx emissions
- PM10 emissions
- SO2 emissions
- CO emissions
- VOC emissions
Select additional chemical emissions to air and water are also available in the tools (e.g., PAHs, toxic metals). WEST and WWEST provide the air emissions results according to the associated life-cycle phase (construction, operation, or maintenance), the process phase for water (supply, treatment, or distribution) or wastewater (collection, treatment, or discharge), activity (material production, material delivery, equipment use, energy consumption, sludge disposal, and direct emissions [WWEST only]), and, for WEST, the water source (e.g., groundwater, reservoir, importation, desalination, and recycling).
What knowledge will I gain from using WEST and WWEST?
WEST users may enter data about an existing, proposed, or hypothetical water or wastewater system to determine the environmental effects of their decisions. WEST and WWEST are designed to be used by people who want a deeper, more complete analysis than WESTWeb can offer. It can be used to improve planning, design, or operational decisions. WEST and WWEST users may enter data about an existing, proposed, or hypothetical water or wastewater system to determine the environmental effects of their decisions. In addition to answering the questions addressed by WESTWeb, WEST and WWEST can inform decisions including:
- MATERIAL SELECTION: For a particular pipeline installation, is concrete or iron or plastic pipe better for the environment? Should I build concrete or metal tanks to store water for distribution?
- PROCESS SELECTION: Which disinfection method is more environmentally detrimental: chlorine, ozone, or ultraviolet light? How can I compare non-conventional treatment processes?
- ENERGY SOURCE SELECTION: What percentage of the environmental effects associated with my utility is associated with material production vs electricity use? What impact would it have if I could capture methane to produce electricity on-site? What if I have more accurate emission factors for my electricity source? How would my results change if the process of producing electricity becomes more efficient (i.e., the emission factors improve)?
- SUPPLIER AND TRANSPORT SELECTION: How much can we reduce our environmental effects by purchasing from local suppliers? Does it help to change the transportation mode for my deliveries from airplane to truck? What if I replace my fleet of vehiles with hybrid or alternate fuel vehicles?
- TREATMENT EMISSION ESTIMATION (WWEST only): IF the IPCC recommended assumptions don't seem to be indicative for my system, how can I customize the assumptions used to estimate the methane emissions from my treatment process?
- DISPOSAL SELECTION: What disposal alternatives should I consider to minimize or even reduce carbon emissions?
- WATER SOURCE SUSTAINABILITY (WEST only): Should I be concerned about the availability and reliability of the water source I am evaluating?
The results from WEST and WWEST are reported in terms of chemical emissions and, unlike WESTWeb, are not currently translated into impact categories. The user can implement impact assessment using a methodology such as IMPACT2002+ which is used in WESTWeb.
Who should use WEST and WWEST?
Water system designers, utility operators, civil engineers, regulators, and researchers are the intended users of these tools. Users should have a working knowledge of water supply or wastewater system, data related to a real or hypothetical water or wastewater system, and a desire to learn more about the environmental and economic implications of their decisions.
What is the methodological basis of WEST and WWEST?
Like WESTWeb, WEST and WWEST combine the power of two proven LCA approaches: process-based LCA and economic input-output analysis-based LCA (EIO-LCA). The details of these two approaches are discussed on the LCA tab.
The structure of WEST is shown in Figure 2. WEST incorporates elements from both process-based LCA and EIO-LCA to yield the most comprehensive results. Generally, EIO-LCA is used to determine the effects of material production, and process-based LCA is used to evaluate material delivery, equipment operation, and energy production.
Figure 2: WEST Structure
The WWEST tool is similarly structured but also includes an additional component which estimates the direct emissions from the treatment process itself using process-based LCA. Figure 3 shows the structure of WWEST, including information on LCA methodologies and required input data.
Figure 3: WWEST Structure
A hybrid LCA approach employed in this research incorporates data from a variety of sources including the on-line EIO-LCA tool for material production emissions, the Environmental Protection Agency's Emissions and Generation Resource Integrated Database (E-GRID) for electricity generation emissions and AP-42 standards for diesel engines, the Department of Energy's Greenhouse gas, Regulated Emissions, and Energy use in Transportation (GREET) model for fuel-related emissions, Caterpillar and other manufacturers for equipment data, the California Air Resources Board's Off-Road Emissions Model for construction equipment emissions, published LCA studies, and others.
More information about methodology is available in prior publications.
In addition, WEST reports information about groundwater and surface water sustainability, or vulnerability, on a statewide basis or, in the case of California, on a county scale. The water stress results for surface water are based on whether an area is drought-prone. The groundwater stress results are based on water level measurements in wells within the region.
What does WEST look like?
The tool takes the user through a series of input worksheets to gather data about: the general system (e.g., location, sources of water, facilities such as treatment plants), initial construction and maintenance materials as well as material transportation distances and modes, on-site construction equipment (e.g., excavator, loader), and electricity consumption
Figure 4 depicts the Project Information worksheet in which the user is expected to provide general inputs.
Figure 4: Entry- Project Information Worksheet
The color convention for cells in WEST is as follows:
- The user should enter data in the PURPLE cells.
- The user should select an option from a drop-down menu in the GREEN cells.
- WEST automatically reads in data from elsewhere in the tool in YELLOW cells; the user can update as needed.
- WEST automatically calculates values in TAN cells; the user can update as needed.
Figure 5 shows another example data entry page. The user enters data about materials used in construction, operation, and maintenance as well as information about material delivery. A companion tool, WESTCalc, is available (by sending an email to the contacts at the end of this page) to estimate the costs and weights o f common materials used in a conventional water supply system.
Figure 5: Entry- Material Production Worksheet
Output worksheets in WEST are available for each activity separately (i.e., material production, material delivery, equipment use, energy use, and sludge disposal). The energy production entry is similar to the page shown for WWEST (see below). A summary worksheet is also available. Figure 6 shows the summary worksheet for a hypothetical system. In this system, only four sources were analyzed.
Figure 6: Summary Results
What does WWEST look like?
The WEST tool is structured by activity but the WWEST tool is structured according to the wastewater system process. The tool takes the user through a series of input worksheets to gather data about: the general system (e.g., location, customer demographics, facilities such as treatment plants), the energy production assumptions, the collection system, the treatment process for both solids and liquids, and the discharge system.
WWEST contains default process information not available in WEST to simplify use. The user can decide the level of detail they wish to enter. There are two types of data input pages: Entry pages and Assumption pages. Entry pages should be completed by all users; assumption pages can be checked and edited by users that want a more detailed, accurate analysis.
Figure 7 depicts the Project Information worksheet in which the user provides general inputs about the utility and facilities.
Figure 7: WWEST Entry- Project Information Worksheet
The color convention for cells in WWEST is the same as described for WEST.
Figure 8 shows another example data entry page. The user enters data about energy production. The WEST entry page is similarly structured. The user can chose between using direct emission factors (i.e., for smokestack emissions) or life-cycle emission factors (i.e., when upstream, supply chain effects are included). The user can also select national average emission factors, state average emission factors, or can customize the factors based on their own energy mix. The user can also edit emission factors for natural gas and fuel combustion and for methane emission factors when methane is burned to create electricity.
Figure 8: WWEST Entry- Energy Production Worksheet
Figures 9a and 9b show a sample data entry page for the treatment processes. Fig. 9a shows most of the processes included in the tool. If the user selects a process, default data from that process will be calculated. The defaults can be verified and edited by navigating to the Assump-LTRT page for liquid processes and the ASSUMP-STRT page for solids. Figure 9b shows more detailed data entry for treatment
Figure 9a: WWEST General Treatment Data Entry
Figure 9b: WWEST Specific Treatment Data Entry
Output worksheets in WWEST are available for each activity separately (i.e., material production, material delivery, equipment use, and energy use). A summary worksheet is also available. The results worksheet looks similar to the results for the WEST tool (see Figure 6).
A list of related publications can be found on the Background tab.
How can I receive a copy of these tools for my own use?
These tools are publicly available and are free of charge.
To obtain a copy of WEST and/or WWEST, please email the developers and include your name, email, phone number, employer, the tool(s) you are using, and the purpose for which you intend to use the tool. If you do so, we will notify you when additional changes and improvements are made. We ask that anyone who uses the tool keeps us informed about suggestions for improvement, necessary revisions, or other comments.
WEST Update Log
|Date||Version number||Sheet(s) edited||Description of change||Details|
|December 30, 2010||1.0||None||Initial tool release||None|
|May 25, 2011||1.1||Project Entry, Results summary, and Water Stress||Added Water Stress calculations||None|
|July 18, 2011||1.1||Project Entry, Results summary, and Water Stress||Added Water Stress calculations||None|
WWEST Update Log
|Date||Version number||Sheet(s) edited||Description of change||Details|
|December 30, 2010||1.0||None||Initial tool release||None|
|June 14, 2011||1.0||Results-EP||Updated calculation for methane offgas electricity production||Corrected a sign problem|
|July 18, 2011||1.0||Project Entry, Results summary, and Water Stress||Added Water Stress calculations||None|
|September 20, 2011||1.1||Treatment and Sludge Treatment sheets||Updated disposal calculations||Corrected errors in landfill methane capture calculations and other minor changes|