Although many guidance documents have been developed to inform the design and operation of building water systems to ensure safe water quality, there is a lack of consensus on some topics. This study interviewed 22 subject matter experts (SMEs) to identify topics of concern for managing water quality in buildings and compared SME views with information available on these topics in 15 systematically screened important guidance documents. The study found 18 design and 11 operational topics as critical for managing water quality in buildings. No one guidance document addressed all these topics, suggesting that a compendium of available guidance is needed. SMEs most frequently recommended temperature and residual disinfectant measurements as good parameters for monitoring overall building water quality. Both SME and guidance document recommendations for temperature for controlling opportunistic pathogen growth were reasonably consistent with water heater setpoint >60 °C. However, hot water temperature recommendations varied between 50 and 55 °C for other locations (i.e., the water temperature at the tap or end of the return loop). On the contrary, recommendations for disinfectant residual levels (0.2–2.0 mg/L), flushing frequency (1–14 days), and allowable time for hot water to reach the tap (10–60 s) were not consistent. While this study was able to reconcile diverging views on some of the water quality topics, such as identifying common guidance for water heater set point to at least 60 °C, it also highlights lack of definitive guidance on other critical topics, such as residual level, flushing frequency, hot water time to tap, and the use of thermostatic mixing valves, indicating that these are significant knowledge gaps that need further investigation. The study concludes that there is a need for developing evidence-based guidance, particularly on the topics where expert opinions diverged.

Renewable fuel standards for biofuels have been written into policy in the U.S. to reduce the greenhouse gas (GHG) intensity of transportation energy supply. Biofuel feedstocks sourced from within a regional market have the potential to also address sustainability goals. The U.S. Mid-Atlantic region could meet the advanced fuel designation specified in the Renewable Fuel Standard (RFS2), which requires a 50% reduction in GHG emissions relative to a gasoline baseline fuel, through ethanol produced from winter barley (Hordeum vulgare L.). We estimate technology configurations and winter barley grown on available winter fallow agricultural land in six Mid-Atlantic states. Using spatially weighted stochastic GHG emission estimates for winter barley supply from 374 counties and biorefinery data from a commercial dry-grind facility design with multiple co-products, we conclude that winter barley would meet RFS2 goals even with the U.S. EPA’s indirect land use change estimates. Using a conservative threshold for soil GHG emissions sourced from barley produced on winter fallow lands in the U.S. MidAtlantic, a biorefinery located near densely populated metropolitan areas in the Eastern U.S. seaboard could economically meet the requirements of an advanced biofuel with the co-production of CO₂ for the soft drink industry.

The development of microalgal biorefineries, utilizing high-value coproducts, offers a strategy to lower production costs, while the use of saline-tolerant microalgal species contributes to reducing freshwater consumption.

Achieving the United States' target of net-zero greenhouse gas emissions by 2050 will require technological transformations and energy sector migration.

District heating (DH) systems can improve energy efficiency, reduce greenhouse gas (GHG) emissions, and be a cost‐effective residential space heating alternative over conventional decentralized heating. This study uses radiative forcing (RF), a time‐sensitive life cycle assessment metric, to evaluate space heating alternatives. We compare forest residue and willow biomass resources and natural gas as fuel sources against decentralized heating using heating oil. The comparison is performed for selected locations in the Northeastern United States over a 30‐year production timeline and 100 observation years. The natural gas and willow scenarios are compared with scenarios where available forest residue is unused and adds a penalty of GHG emissions due to microbial decay. When forest residues are available, their use is recommended before considering willow production. Investment in bioenergy‐based DH with carbon capture and storage and natural‐gas‐based DH with carbon capture and storage (CCS) technology is considered to assess their influence on RF. Its implementation further improves the net carbon mitigation potential of DH despite the carbon and energy cost of CCS infrastructure. Soil carbon sequestration from willow production reduces RF overall, specifically when grown on land converted from cropland to pasture, hay, and grassland. The study places initial GHG emissions spikes from infrastructure and land‐use change into a temporal framework and shows a payback within the first 5 years of operation for DH with forest residues and willow.