Cost and Energy Metrics for Municipal Water Reuse

Abstract

Municipal water reuse can contribute to a circular water economy in different contexts and with various treatment trains. This study synthesized information regarding the current technological and regulatory statuses of municipal reuse. It provides process-level information on cost and energy metrics for three potable reuse and one nonpotable reuse case studies using the new Water Techno-economic Assessment Pipe-Parity Platform (WaterTAP3). WaterTAP3 enabled comparisons of cost and energy metrics for different treatment trains and for different alternative water sources consistently with a common platform. A carbon-based treatment train has both a lower calculated levelized cost of water (LCOW) ($0.40/m3) and electricity intensity (0.30 kWh/m3) than a reverse osmosis (RO)-based treatment train ($0.54/m3 and 0.84 kWh/m3). In comparing LCOW and energy intensity for water production from municipal reuse, brackish water, and seawater based on the largest facilities of each type in the United States, municipal reuse had a lower LCOW and electricity than seawater but higher values than for production from brackish water. For a small (2.0 million gallon per day) inland RO-based municipal reuse facility, WaterTAP3 evaluated different deep well injection and zero liquid discharge (ZLD) scenarios for management of RO concentrate. Adding ZLD to a facility that currently allows surface discharge of concentrate would approximately double the LCOW. For all four case studies, LCOW is most sensitive to changes in weighted average cost of capital, on-stream capacity, and plant life. Baseline assessments, pipe parity metrics, and scenario analyses can inform greater observability and understanding of reuse adoption and the potential for cost-effective and energy-efficient reuse.

Potential Water and Energy Savings for Reducing Urban Water Supply Loss in China

“…As shown in our scenario analysis, for many water-starved cities in North China, which relied on water received from SNWTP, effectively controlling local water loss can be a significant supplement to local water supply to improve the SNWTP’s overall efficiency and to optimize the national water resources, given the considerable water-saving potential for such cities in the future. Considering the fact that the SNWTP may induce extra energy and material consumption in the water treatment and sanitization during the water transport for the final clean water use, − prioritizing the water loss control in the water-scarce northern cities with greater water losses can effectively reduce the potential water transport and thus serve as an effective supplement to the national water resources’ optimal allocation. In addition, such targeted water loss control may also make an important contribution to energy saving associated to the water supply system, and the consequent carbon emission reduction, as well as the achievement of Sustainable Development Goals (SDGs) in China.…”

Quantitative sustainable design (QSD) for the prioritization of research, development, and deployment of technologies: a tutorial and review

“…260 Sensitivity analysis can be classified as local or global based on whether the effects of input variables are evaluated in the vicinity of a base point (local) or across the entire problem space (global). 261,262 Local methods can be used for quick assessment of parameters' impact on the system's sustainability (e.g., with single-point sensitivity analysis at the minimum/maximum values of a parameter 263,264 ), but global methods are recommended when possible because they are more robust and can be more informative (e.g., yielding more generalizable insight across the problem space). 44,265 In QSD, Fig.…”

“…261,262 Local methods can be used for quick assessment of parameters' impact on the system's sustainability ( e.g. , with single-point sensitivity analysis at the minimum/maximum values of a parameter 263,264 ), but global methods are recommended when possible because they are more robust and can be more informative ( e.g. , yielding more generalizable insight across the problem space).…”

Lack of Clarity Around Policies, Data Management, and Infrastructure May Hinder the Efficient Use of Reclaimed Water Resources in the United States

“…Infrastructure and technology considerations naturally include a number of economic factors that can influence the feasibility of new water reuse projects and sustainability of existing projects. Across the United States, there are examples of municipalities choosing to build entirely new water recycling facilities, while others retrofit and expand existing wastewater treatment plants; there is a wide range of costs associated with either new construction or retrofitting different treatment trains . For small non-potable reuse projects, the cost of constructing new distribution lines may make up a majority of the total costs of a project, but in other cases, advanced treatment processes may dominate total costs .…”

“…Across the United States, there are examples of municipalities choosing to build entirely new water recycling facilities, while others retrofit and expand existing wastewater treatment plants; there is a wide range of costs associated with either new construction or retrofitting different treatment trains . For small non-potable reuse projects, the cost of constructing new distribution lines may make up a majority of the total costs of a project, but in other cases, advanced treatment processes may dominate total costs . Pricing reclaimed water to internalize these costs while balancing affordability is the subject of a growing body of literature from academic, professional, and regulatory bodies. ,− The state of Louisiana, for example, has directly addressed this issue by requiring that the cost of reclaimed water (including transportation) be less than alternative potable water supplies in certain contexts (LA Rev Stat § 30:2396).…”