Francis de los Reyes III
- Comparing Rates of Change in SARS-CoV-2 Wastewater Load and Clinical Cases in 19 Sewersheds Across Four Major Metropolitan Areas in the United States , ACS ES&T Water (2022)
- Meeting the Water and Sanitation Challenges of Underbounded Communities in the US , ENVIRONMENTAL SCIENCE & TECHNOLOGY (2022)
- Multifaceted Assessment of Wastewater-Based Epidemiology for SARS-CoV-2 in Selected Urban Communities in Davao City, Philippines: A Pilot Study , INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH (2022)
- Chlorophyll a and non-pigmented biomass are sufficient predictors for estimating light attenuation during cultivation of Dunaliella viridis , ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS (2021)
- Development of trash exclusion for mechanized pit latrine emptying , ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY (2021)
- Global Water, Sanitation, and Hygiene Approaches: Anthropological Contributions and Future Directions for Engineering , ENVIRONMENTAL ENGINEERING SCIENCE (2021)
- Impact of sampling depth on pathogen detection in pit latrines , PLOS NEGLECTED TROPICAL DISEASES (2021)
- Microbial Contamination in Environmental Waters of Rural and Agriculturally-Dominated Landscapes Following Hurricane Florence , ACS ES&T Water (2021)
- SARS-CoV-2 Wastewater Surveillance for Public Health Action , EMERGING INFECTIOUS DISEASES (2021)
- Sars-Cov-2 Wastewater Surveillance for Public Health Action: Connecting Perspectives From Wastewater Researchers and Public Health Officials During a Global Pandemic ,  (2021)
The goal of the project is to develop a low-cost, portable auger-based technology that can reliably and hygienically empty a wide variety of pit latrines and septic tanks containing wastes with a range of moisture and trash contents. After extensive field and lab testing, we have finalized an EV design that was successful in emptying pit latrines in the field while successfully excluding trash. Two technologies have been developed: a mechanized trash excluder that actively rejects trash in a pit while allowing emptying of the fecal sludge, and a complete, low-cost system that uses a vacuum and an excluder to empty the de-trashed fecal sludge to pit-side containers (currently called ÃƒÂ¢Ã¢â€šÂ¬Ã…â€œFlexcrevatorÃƒÂ¢Ã¢â€šÂ¬Ã‚Â). We also recently finished a generalized market/business analysis for both technologies. NC StateÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s focus during this part of the project will be to coordinate work with potential commercial partners and contractors to design, build, and test Design Validation (DV) trash excluders. The primary outcomes and results will be: ÃƒÂ¢Ã¢â€šÂ¬Ã‚Â¢ Design, build a minimum of five (5) DV trash excluder units and create the necessary documentation for Design Validation with an outside contract manufacturer (per New Product Development Guideline) ÃƒÂ¢Ã¢â€šÂ¬Ã‚Â¢ Testing a minimum of two units (2) units in Ghana with an interested commercial partner (iDE Ghana/Sama Sama) over the course of at least 7 months as a means to understand the performance of the unit and collect commercialization data. This information will be used to develop business model documentation in Ghana, including supply chain, marketing, financing, sales plan. ÃƒÂ¢Ã¢â€šÂ¬Ã‚Â¢ Testing of the two (2) units will also include a study led by NC State on gender impacts: how the trash excluder operation, access, ownership/business operation, and the how the business of pit emptying is affected by gender. The goal is to identify barriers to inclusive use of the device and define explicit ways to remove these barriers.
In the continuing quest to relate microbial communities in bioreactors to function and environmental and operational conditions, engineers and biotechnologists have adopted the latest molecular and ÃƒÂ¢Ã¢â€šÂ¬Ã‹Å“omic methods. Despite the large amounts of data generated, gaining mechanistic insights and using the data for predictive and practical purposes is still a huge challenge. This project will use a methodological framework to guide experimental design to improve the operation, start-up, and resilience and resistance of anaerobic bioreactors co-digesting food and FOG wastes. This research represents leading edge work to combine molecular microbial methods, bioreactor experiments, and modeling to identify and exploit the underlying factors that govern microbial community assembly in anaerobic co-digestion systems.
While significant research has been conducted to date on the benefits and process limitations of co-digestion of GIW with municipal biosolids in a traditional anaerobic digestion process, there is very little knowledge on the benefits and limitations of co-digestion of GIW with municipal biosolids in a process that includes thermal hydrolysis pretreatment process (THP) upstream of the anaerobic digestion process. The proposed study would focus on understanding the benefits and process limitations of co-digestion of GIW with municipal biosolids that have been pretreated with THP. This study will also consider how GIW addition shifts the nutrient concentrations in the anaerobic digestion process and how the reduction in nutrient concentrations impacts microbial population and kinetics in the anaerobic digestion process (i.e., does reduced nutrient content result in less stress on the microbial population in the anaerobic digestion process). This research will benefit the City of Raleigh and other utilities that are considering implementing THP to enhance their digestion process to understand the benefits and limitations of GIW co-digestion with this process. This research will also help to provide much needed information for full-scale implementation of GIW co-digestion in a THP + MAD process, which would ultimately result in an additional outlet option for GIW.
Wastewater treatment with Anaerobic Ammonium Oxidation (Anammox) holds the promise of significantly reducing energy and chemical costs associated with nitrogen removal from wastewater The Anammox process involves the anaerobic conversion of nitrite to nitrogen gas with ammonium as the electron donor. While used more regularly in side-stream applications, the use of mainstream Anammox is still limited. Most of the challenges associated with widespread application of Anammox for mainstream nitrogen removal involve the Anammox bacteria being outcompeted by other, more robust organisms commonly found in wastewater and utilized for conventional nitrogen removal. However, in addition to process challenges there are also significant costs associated with a change in infrastructure. One novel possibility that may address both challenges would be to convert existing filter infrastructure into tertiary Anammox filters for mainstream nitrogen removal. For the past two years our research team operated a preliminary pilot Anammox filter at the Neuse River Resource Recovery Facility in Raleigh, NC. While the filter showed exciting promise (> 90% TIN removal in some cases), the controlled nature of the influent into our preliminary pilot filter limited the applicability of the results. This study would build on our experience, and push the frontier of research on sustainable nitrogen removal in wastewater treatment. The primary objective of this study is to compare a pilot scale tertiary Anammox filter to a traditional denitrification filter, under a range of realistic operating conditions. We hypothesize that the Anammox filter will lead to significant cost savings while achieving similar or superior results to a traditional denitrification filter.
Anaerobic digestion (AD) or co-digestion of food waste provides the dual benefits of enabling the sustainable production of energy while providing an alternative disposal option for these ubiquitous wastes. The key to economically feasible AD of food wastes is maintaining high and stable methane yields under various loading and substrate conditions. However, the interactions between substrate variability (different food wastes, loading) and microbial community adaptations are not known, even though these directly impact process resilience and resistance. This is an important issue in full scale operation, since the collected food waste can vary in type, strength, and characteristics on a seasonal, daily, or per load basis. The overall objective of this project is to understand substrate-community interactions to optimize anaerobic digestion of food waste, particularly to increase process resilience and resistance to varying waste types and loads. This will lead to operational procedures that can be used in full-scale implementation of AD of food wastes by municipal utilities and industry.
This is for an NSF ERc Planning Grant to prepare for an ERC proposal. SWIFT-MCÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s vision is a future of sanitation and water infrastructure that supports the well-being of marginalized communities and supports sustainable development. These communities disproportionately bear the burden of environmental and health risks, and are not typically prioritized by advances in engineering and technology. To address this complex societal problem, SWIFT-MC will innovate sanitation and water infrastructure (SWI) through deep collaboration across disciplines (e.g., engineering, social and behavior sciences, public health) and active partnership and engagement with marginalized communities, policy makers, and technology designers and developers. As a result, the SWI will be designed, implemented, and maintained equitably to serve the needs of marginalized communities with unique community characteristics and constraints and to achieve desired system properties such as efficiency, flexibility, environmental sustainability, and resiliency.
North Carolina has been selected as one of eight pilot states in the Centers for Disease Control and Prevention (CDC) National Wastewater Surveillance System (NWSS). This system will provide information on the presence and persistence of SARS-CoV-2-like viruses in wastewater systems as a metric of community COVID-19 prevalence. This approach provides a relatively low-cost way to measure both symptomatic and asymptomatic COVID-19 infections without dependence on supply chains for clinical testing supplies or access to clinical testing. Wastewater surveillance can demonstrate trends in COVID-19 prevalence, direct action to protect public health, and allay concerns about the burden of disease when SARS-CoV-2 concentrations are low. NC State University will support this project by collecting, preparing, and shipping samples to the UNC laboratory (Rachel Noble, PI).
The primary goal of the proposed research is to elucidate COVID-19 infection dynamics by monitoring for SARS-CoV-2 RNA in wastewater and sewage in four major metropolitan areas of the US. Influent wastewater (~500 mL) and primary solids (~40 mL) will be collected at wastewater treatment plants serving populations > 100,000 in Los Angeles, Raleigh, Houston and Washington DC. Whenever possible, we will also collect sewage samples within the sewerage network to provide greater resolution of infection dynamics across a city. Samples will be stored at -80 C and analyzed by RT-qPCR when labs are open again. Normalization of SARS-CoV-2 RNA concentrations in wastewater to per capita mass loads using daily flow and population served will provide community-scale information on COVID-19 infection.This coordinated effort across four cities is a unique strength of this work. We hypothesize that the value of wastewater monitoring to track infection dynamics will be influenced by local factors (e.g., whether there is a combined or separate sewerage system, weather events, and wastewater strength) and therefore we chose four cities that represent a wide range of those parameters. There is also a wide range in diagnostic testing capacity across the four cities, with DC having done the most tests per capita and Houston the fewest. The value added of sewage surveillance to clinical diagnostic testing is likely greater in cities with lower testing capacity; we will use our data to test this hypothesis.
Building on our Phase I results, we will continue to improve and develop a low-cost, portable auger-based technology that can reliably and hygienically empty a wide variety of pit latrines and septic tanks (pits) containing wastes with a range of moisture contents. Thus one machine can be used in watery, low solids pits (e.g, as occur in Malawi), and high solids and trash pits (e.g., as occur in eThekwini municipality in South Africa). We envision that a successful device will be used by local entrepreneurs or local governments in emptying pits all over the world, thus reducing the dangerous, unhygienic, and undignified practice of manual pit emptying.
Approximately 3.3 million North Carolinians (35% of the population) rely on private wells as their primary source of drinking water.1 Well water quality is not regulated at the state or federal level, despite several studies illustrating a link between well water contamination and adverse health outcomes.2,3 Moreover, well water can contain harmful organic contaminants such as pesticides, but occurrence data are sparse.4 Key goals of the proposed research are to characterize pesticide contamination in private well water across the state and develop information for the selection of effective home treatment devices.