2020 Project Spotlights
The energy required to supply water changes significantly with shifting supplies and demands. Future stresses like climate change and population growth, as well as potential innovations in water treatment and management, affect predictions of embedded energy and associated greenhouse gas emissions in our water supply. Understanding trends and their drivers will support integrated resource management, assist in prioritizing investments, and target policy mechanisms to address challenges before long term impacts occur.
2019 Project Spotlights
The i-DST is a planning-level stormwater decision support tool that helps practitioners select the most appropriate combination of green, grey, and/or hybrid infrastructure. The tool is modular and composed of site-scale and sewer-shed scale hydrologic modeling, life cycle cost and life cycle assessment, and a co-benefit analysis.
Reclamation of wastewater to produce potable-quality water offers significant opportunities to minimize freshwater withdrawals, improve sustainability, and build resilience against water scarcity by investing in local water sources. This project aims to demonstrate an algal-osmosis membrane treatment system for resource recovery from municipal wastewater including potable quality water and algal biomass for bioenergy and fertilizer. The core components of the system include a mixotrophic algal process for removal of biochemical oxygen demand (BOD) and nutrients, followed by a hybrid forward osmosis (FO)-reverse osmosis (RO) system for separation of biomass from the algal effluent and production of potable-quality water.
Accurate methods to predict impervious surface connectivity are needed to improve hydrologic modeling and efficient siting of distributed stormwater technologies. ReNUWIt researchers are developing a new method for estimating impervious surface connectivity across different soil types, slopes, rainfall scenarios and landcover parameters. The outcomes of this research may be used as hydrologic model inputs and to inform more efficient distributed stormwater control siting across heterogeneous urban landscapes.
Stormwater infrastructure is required to safely manage uncertain precipitation events of varying intensity, while protecting natural ecosystems, under restricted financial budgets. The purpose of this project is to devise more realistic design-phase indicators of stormwater system performance under precipitation uncertainty, by applying and further developing a formal verification method called reachability analysis.
Direct potable reuse (DPR) treatment trains are designed to achieve high levels of pathogen removal, but little is known about how advanced treatment alters the entire water microbiome, and whether blending and introducing advanced treated water into conventional distribution systems presents any unique microbiological risks. This project aims to fill these knowledge gaps and to develop new methods for understanding and maintaining microbial water quality in DPR projects.
Concerns about the impact of climate, seasonality, fooprint and disruptive events on performance have limited broader adoption of treatment wetlands. ReNUWIt researchers are exploring nitrogen treatment and underlying mechanisms within a macrophyte-free, photosynthetic engineered wetland field-scale construct that is coupled to biologically active flow-manipulating structures. In concert, this approach has the potential to increase system reliability and resilience while decreasing overall footprint needs for optimal water treatment.
Water infrastructure planning and management requires a deep knowledge of water use across all sectors. Utilizing high-resolution water use data produced by emerging smart metering technologies, ReNUWIt researchers have examined a previously understudied subsector, nonresidential large landscape irrigation, to gain insights into customer behavior.
ReNUWIt researchers are evaluating ways to control disinfection byproduct (DBP) formation, including THMs and NDMA, in reuse systems by altering the way that disinfectants are added. Additionally, researchers are developing a new framework that industry and regulators can apply to compare the chemical quality of reuse waters and conventional drinking waters, as well as identify which chemicals likely contribute most to the chemical toxicity of the waters.
This research investigates the use of low water consuming native vegetation and geo-engineering techniques to reinvent stormwater conveyance and detention systems in urban settings. The outcomes of this research will help restructure drainage and river systems in arid urban environments to be more effective in trapping sediment and other contaminants from flood runoff to further prevent contamination of surface and groundwater, sustain native vegetation, and improve aesthetics for economic development.
Biochar amendments to conventional bioretention design can increase the removal of water soluble trace organics from stormwater that are not well removed with existing bioretention specifications. Soluble organics are of concern because they are less likely to sorb to geomedia or soil and are thus more likely to contaminate receiving waters.
Efficient techniques for both energy and nutrient recovery are needed to transform wastewater treatment plants into water resource recovery facilities. ReNUWIt researchers are developing integrated aqueous systems to convert wastewater-derived biomass into valuable products including hydrocarbon fuels, fertilizers, and chemical intermediates, thereby realizing the simultaneous treatment and valorization of wastewater.
ReNUWIt researchers have developed BIOCHARge, biochar-augmented stormwater biofilters. The biofilters contain a mixture of sand and biochar which effectively remove microbial contaminants, including fecal indicator bacteria, bacteria pathogens, and coliphage from stormwater. The pollutant removal capabilities of BIOCHARge are one of the multiple benefits of stormwater biofilters and green infrastructure.
2018 Project Spotlights
ReNUWIt researchers have partnered with the Santa Clara Valley Water District and the San Francisco Estuary Institute to develop a cost-effective approach for removing trace organic contaminants, nutrients and metals from reverse osmosis concentrate prior to its discharge. If successful, the technology will make it possible for utilities that do not have access to an ocean outfall to employ reverse osmosis in potable water reuse projects without adversely impacting aquatic ecosystems.
Anaerobic secondary treatment of wastewater has the potential to convert wastewater treatment plants from major energy consumers into renewable power plants. The Staged Anaerobic Fluidized Bed Membrane Bioreactor (SAF-MBR) is a promising system that has been deployed as a pilot at the Codiga Resource Recovery Center testbed at Stanford and is now being tested at a full-scale wastewater treatment plant operated by industry partner Silicon Valley Clean Water in Redwood City, CA. In initial testing at Stanford, the SAF-MBR system has consistently achieved >90% chemical oxygen demand (COD) removal.
ReNUWIt researchers at UC-Berkeley are working to identify the engineering design characteristics and regulatory opportunities and barriers relevant to the potential for widespread implementation of BEST (biohydrochemical enhancements for streamwater treatment) facilities. This research is being completed in collaboration with ongoing technical research into BEST systems by ReNUWIt researchers at Colorado School of Mines. Engineering design opportunities include the potential for aesthetic and recreational co-benefits, which bring with them the potential for co-funding of infrastructure development from a range of non-traditional sources. Regulatory opportunities and barriers include understanding what performance data and technical characteristics are desired to gain recognition of a new technology by relevant regulatory and non-regulatory “gatekeepers” of new stormwater technologies.
The Living Levee is an innovative, multi-benefit system used to combat the effects of sea-level rise in coastal urban areas. It is a sloped, subsurface constructed wetland designed to buttress existing storm control levees to protect them from storm surges, improve wetland habitat, and provide additional treatment to municipal wastewater effluent. Pilot scale results suggest that nutrients and recalcitrant trace organic contaminants can be removed effectively in this type of system if hydrology is appropriately considered during design.
A ReNUWIt research team has demonstrated a 700-L pilot scale version of the POWER (Photosynthetically Oxygenated Waste-to-Energy Recovery) system at the Las Cruces Wastewater Treatment Plant in Las Cruces, NM. Fed-batch operations of this algae-based pilot scale system achieved discharge standards for BOD, N, and P in a single step within 3 days. Comparison of the bacterial water quality of the algal effluent with the secondary effluent, confirmed superior performance of the POWER system.
A ReNUWIT research team has developed a software toolkit, IRIPT (Integrated Urban Reclaimed Water Infrastructure Planning Toolkit), that facilitates planning and design of reclaimed water infrastructure for both centralized and hybrid configurations that incorporate satellite treatment plants (STPs). The toolkit gives decision-makers the ability to analyze many configurations across a wide range of scales, facilitating more transparent decision-making, engaging stakeholders, and increasing chances of socially acceptable and equitable solutions that satisfy many needs simultaneously.
Strormwater quality management approaches are typically focused on improving water quality before or within a storm drain system. Researchers are developing BEST (biohydrochemical enhancements for streamwater treatment) to provide an in-stream treatment option.
While the accepted industry standard potable reuse treatment train reliably produces high-quality water, there are a number of factors, such as energy use and concentrate management, that have constrained widespread implementation of these systems. ReNUWIt researchers are evaluating alternative potable reuse treatment trains with the goal of addressing some of these factors.
The tradeoffs between system size and technology performance are an important consideration for utilities evaluating decentralized infrastructure. ReNUWIt’s life-cycle assessment (LCA) tool with location specific techno-economic and environmental models can assist decision makers when planning for implementation of decentralized water reuse and nitrogen recovery.
Long approached from a flood control and pollution management perspective, urban stormwater runoff is now also seen as a potential water supply source for recharging groundwater aquifers. New geomedia-based stormwater treatment systems being pilot tested by ReNUWIt researchers in Los Angeles, California have the potential to provide a reliable and cost-effective treatment solution that could turn this vision into a reality.
2017 Project Spotlights
Achieving energy positive wastewater treatment is hindered by a heavy reliance on energy intensive aerobic processes. The Coupled Hybrid Anaerobic Process for Generation of Energy (CHARGE) eliminates the energy requirement for organic matter oxidation, reduces the amount of waste biomass production to 1% of the influent organic carbon while concurrently generating methane.
Infrastructure costs are a key barrier to new recycled water projects. ReNUWIt’s new methods minimize these costs through design optimization to deliver recycled water to underutilized stormwater spreading basins.