Water- and Energy-Efficient Appliances for Circular Water Economy: Conceptual Framework Development and Analysis of Greenhouse Gas Emissions and Water Consumption

Abstract

The concept of circular water economy has emerged for the sustainable and resilient use of water and for mitigating attendant greenhouse gas (GHG) emissions. Although macroscale circular water economy has been widely addressed, analysis of microscale household circular water economy, including water–energy nexus aspects, has not been thoroughly developed and documented. In this study, we quantify the contribution of household water and energy use to water consumption and GHG emissions. We develop a comprehensive spreadsheet-based input–output model to calculate the net GHG emission expressed as carbon dioxide equivalent (CO2e) and water consumption levels of household appliances for various supply- and demand-side scenarios. We quantitatively evaluate the impact of temporally and spatially varying emission factors of energy production on the GHG emissions and water consumption for a model household that employs appliances with various efficiency levels. To advance the concept of a circular water economy, we develop a framework for considering water reduction, reuse, recycling, and recovery, along with retrofitting/remanufacturing of water and energy appliances and fixtures. Finally, we illustrate the choices in household water and energy systems through a trade-off analysis based on the capital and annual costs of each appliance.

Environmental assessment of casual dining restaurants in urban and suburban areas of peninsular Malaysia during the COVID-19 pandemic

“…Recently, food waste treatments, such as composting and anaerobic digestion, were shown to be able to recover resources and energy, while waste avoidance provides far greater environmental and economic sustainability (Marrucci et al, 2020 ; Slorach et al, 2019 ). Other than that, urban farming and local production of food could also help in climate change mitigation (Paiho et al, 2021 ), apart from utilising water- and energy-efficient appliances (Geglio et al, 2021 ).…”

Carbon Emission Calculations and Reductions in Membrane Water Treatment: A Review

“…108−110 Geglio et al conducted an analysis of the economics of microhousehold circulating water and showed that the use of membrane bioreactors for wastewater treatment and recycled water for irrigation or toilet flushing could save 92 m 3 of water, 26 kWh of energy, and 10.79 kg of carbon dioxide emissions. 48 At present, in addition to being used in urban applications, recycled water treated by RO and combined processes has reached the standard for recycled drinking water. 111−113 Figure 5 summarizes several membrane processes and their recycled water utilization pathways.…”

“…Membrane technology can simultaneously achieve pollutant removal and reclaimed water production, and is widely used in various scenarios. In industrial production, the application of membrane technology enables factories to recycle water resources and achieve self-sufficiency, reducing their greenhouse gas emissions. − Geglio et al conducted an analysis of the economics of microhousehold circulating water and showed that the use of membrane bioreactors for wastewater treatment and recycled water for irrigation or toilet flushing could save 92 m 3 of water, 26 kWh of energy, and 10.79 kg of carbon dioxide emissions . At present, in addition to being used in urban applications, recycled water treated by RO and combined processes has reached the standard for recycled drinking water. − Figure summarizes several membrane processes and their recycled water utilization pathways. − …”