Experimental evaluation of a full-scale in-duct UV germicidal irradiation system for bioaerosols inactivation.

Bioaerosols control techniques, especially ultraviolet germicidal irradiation (UVGI) are gaining attention due to increasing needs for controlling of health risk caused by airborne biocontaminants. The effectiveness of a full-scale in-duct UVGI air disinfection system was investigated. One bacterium, a wild type Escherichia coli, and three fungal spores, Penicillium aragonense, Rhodotorula glutinis, and Cladosporium sp.

Optimization of the IntraVascular Oxygenator Catheter Using Angular Oscillation.

We demonstrate a methodology which both improves oxygen transport and reduces or eliminates bubble formation in a novel hyperbaric membrane oxygenator catheter model system. Angular oscillations were introduced to a bundle of hollow fiber membranes (HFMs) supplied with hyperbaric 100% oxygen at average gauge pressures up to 0.35 barg.

Supercritical water oxidation for the destruction of spent media wastes generated from PFAS treatment.

Granular activated carbon (GAC) and anion exchange resin (AIX) have been successfully demonstrated to remove per- and polyfluoroalkyl substances (PFAS) from contaminated water and wastewater. These treatment technologies, when applied for PFAS removal, generate spent media loaded with a high mass of PFAS requiring further treatment and disposal. This project is the first study on the use of supercritical water oxidation (SCWO) to destroy both the spent media and the PFAS adsorbed onto it.

Intravascular Gas Exchange: Physiology, Literature Review, and Current Efforts.

Acute respiratory failure with inadequate oxygenation and/or ventilation is a common reason for ICU admission in children and adults. Despite the morbidity and mortality associated with acute respiratory failure, few proven treatment options exist beyond invasive ventilation. Attempts to develop intravascular respiratory assist catheters capable of providing clinically important gas exchange have had limited success.

Quantitative microbial risk assessment of outdoor aerosolized pathogens in cities with poor sanitation.

The aeromicrobiological transmission pathway of enteric pathogens in places with unsafe sanitation services is poorly understood. In an attempt to partly fill this knowledge gap, we assessed the potential public health impact of bioaerosols near open waste canals (OWCs) using Quantitative Microbial Risk Assessment (QMRA). We used data acquired in La Paz, Bolivia to characterize the risk of disease that aerosolized enteric pathogens may pose through food, fomites and inhalation (all followed by ingestion).

Quantitative risk assessment of COVID-19 aerosol transmission indoors: a mechanistic stochastic web application.

An increasing body of literature suggests that aerosol inhalation plays a primary role in COVID-19 transmission, particularly in indoor settings. Mechanistic stochastic models can help public health professionals, engineers, and space planners understand the risk of aerosol transmission of COVID-19 to mitigate it. We developed such model and a user-friendly web application to meet the need of accessible risk assessment tools during the COVID-19 pandemic.

Detection and Quantification of Enteric Pathogens in Aerosols Near Open Wastewater Canals in Cities with Poor Sanitation.

Urban sanitation infrastructure is inadequate in many low-income countries, leading to the presence of highly concentrated, uncontained fecal waste streams in densely populated areas. Combined with mechanisms of aerosolization, airborne transport of enteric microbes and their genetic material is possible in such settings but remains poorly characterized. We detected and quantified enteric pathogen-associated gene targets in aerosol samples near open wastewater canals (OWCs) or impacted (receiving sewage or wastewater) surface waters and control sites in La Paz, Bolivia; Kanpur, India; and Atlanta, USA, via multiplex reverse-transcription qPCR (37 targets) and ddPCR (13 targets).

Evaluation of private well contaminants in an underserved North Carolina community.

On-site sewage treatment systems can be an important source of antibiotic resistant bacteria and organic micropollutants into adjacent groundwater. Due to the frequent proximity of private wells to septic systems, this contamination is a concern to communities that do not have access to public municipal services. In both rural and urban environments, low-income communities, indigenous communities and those of color are disproportionately affected by well contamination.

Open Waste Canals as Potential Sources of Antimicrobial Resistance Genes in Aerosols in Urban Kanpur, India.

Understanding the movement of antimicrobial resistance genes (ARGs) in the environment is critical to managing their spread. To assess potential ARG transport through the air via urban bioaerosols in cities with poor sanitation, we quantified ARGs and a mobile integron (MI) in ambient air over periods spanning rainy and dry seasons in Kanpur, India (n = 53), where open wastewater canals (OWCs) are prevalent. Gene targets represented major antibiotic groups-tetracyclines (tetA), fluoroquinolines (qnrB), and beta-lactams (blaTEM)-and a class 1 mobile integron (intI1).

Antimicrobial resistance genes are enriched in aerosols near impacted urban surface waters in La Paz, Bolivia.

Antibiotic resistance poses a major global health threat. Understanding emergence and dissemination of antibiotic resistance in environmental media is critical to the design of control strategies. Because antibiotic resistance genes (ARGs) may be aerosolized from contaminated point sources and disseminated more widely in localized environments, we assessed ARGs in aerosols in urban La Paz, Bolivia, where wastewater flows in engineered surface water channels through the densely populated urban core.

Development of a novel intravascular oxygenator catheter: Oxygen mass transfer properties across nonporous hollow fiber membranes.

Despite hypoxic respiratory failure representing a large portion of total hospitalizations and healthcare spending worldwide, therapeutic options beyond mechanical ventilation are limited. We demonstrate the technical feasibility of providing oxygen to a bulk medium, such as blood, via diffusion across nonporous hollow fiber membranes (HFMs) using hyperbaric oxygen. The oxygen transfer across Teflon® membranes was characterized at oxygen pressures up to 2 bars in both a stirred tank vessel (CSTR) and a tubular device mimicking intravenous application.

Technical evaluation and optimization of a mobile septage treatment unit.

A mobile septage treatment unit was built in India using readily available filters and membranes (mesh fabric, sand, granular activated carbon (GAC), microfilter, ultrafilter) and installed on the bed of a small truck. The target application was emptying of septic or sewage holding tanks and concentration of suspended solids while generating a liquid that could be discharged. The system was evaluated for operational and treatment performance while processing septage in the field at 108 sites in Tamil Nadu, India.

Environmental and Aerosolized Severe Acute Respiratory Syndrome Coronavirus 2 Among Hospitalized Coronavirus Disease 2019 Patients.

During April and May 2020, we studied 20 patients hospitalized with coronavirus disease 2019 (COVID-19), their hospital rooms (fomites and aerosols), and their close contacts for molecular and culture evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Among >400 samples, we found molecular evidence of virus in most sample types, especially the nasopharyngeal (NP), saliva, and fecal samples, but the prevalence of molecular positivity among fomites and aerosols was low. The agreement between NP swab and saliva positivity was high (89.

Novel Integrated Biotrickling Filter-Anammox Bioreactor System for the Complete Treatment of Ammonia in Air with Nitrification and Denitrification.

An integrated biotrickling filter-anammox bioreactor system for the complete treatment of ammonia in air with conversion to nitrogen gas without the supply of an extraneous electron donor for denitrification was established. Partial nitritation (i.e.

Capillary microbioreactors for VOC vapor treatment: Impacts of operating conditions.

Micro-capillary bioreactors (1 mm ID, 10 cm long) were investigated for the biodegradation of toluene vapors as a model volatile organic compound (VOC). The intended application is the removal of VOCs from indoor air, when such microbioreactor is coupled with a microconcentrator that intermittently delivers high concentrations of VOCs to the bioreactor for effective treatment. The effects of key operating conditions were investigated.

Nutrient removal from human fecal sludge digestate in full-scale biological filters.

There is a great need for simple methods for digestate management for potential household sanitation systems based on anaerobic digestion of minimally diluted fecal waste in countries that lack safe sanitation. Herein, a full-scale three-stage filter for nitrogen and phosphorus removal from anaerobic digester effluent was implemented in Madagascar. It included a trickling filter with crushed charcoal (for aerobic nitrification), a submerged anaerobic filter with bamboo chips (for denitrification), and a submerged filter with scrap iron (for phosphorus removal).

Biological Co-treatment of HS and reduction of CO to methane in an anoxic biological trickling filter upgrading biogas.

This study investigated the feasibility of co-treating HS and CO in a biological trickling filter (BTF) inoculated with hydrogenotrophic methanogens (HMs) and nitrate-reducing, sulfur-oxidizing bacteria. This was accomplished by introducing a pure culture of Thiobacillus denitrificans in a BTF that was successfully upgrading a biogas mimic (60:40 CH:CO) to >97% methane using an enriched HM consortium. Nitrate was fed as the electron acceptor to oxidize HS.

Fecal Malodor Detection Using Low-Cost Electrochemical Sensors.

Technology innovation in sanitation is needed for the 4.2 billion people worldwide, lacking safely managed sanitation services. A major requirement for the adoption of these technologies is the management of malodor around toilet and treatment systems.

Bioaerosol sampling optimization for community exposure assessment in cities with poor sanitation: A one health cross-sectional study.

Evidence of exposure to enteric pathogens through the air and associated risk of infection is scarce in the literature outside of animal- or human-waste handling settings. Cities with poor sanitation are important locations to investigate this aerial exposure pathway as their rapid growth will pose unprecedented challenges in waste management. To address this issue, simple surveillance methods are needed.

Resources recovery from high-strength human waste anaerobic digestate using simple nitrification and denitrification filters.

Simple trickling nitrification filters and submerged denitrification filters were developed to provide post-treatment to high-strength human waste anaerobic digestate with the aims to (i) effectively recover nutrients in a useful form as a fertilizer and to (ii) treat digestate such that it could be reused as flush water in water scarce regions. The tested filter media (biochar, granular activated carbon, rice and coconut husks, bamboo chips, sunflower seeds, and zeolite) are low cost and sustainable materials and can be locally sourced where on-site sanitation facilities are in high demand. Experimental data from laboratory operation with digestate from anaerobic digestion of dog feces and human urine revealed that the filters achieved a combined removal of chemical oxygen demand (COD), total nitrogen (TN), and phosphorus (PO-P) up to 84%, 69%, and 89%, respectively.

Detailed investigations of dissolved hydrogen and hydrogen mass transfer in a biotrickling filter for upgrading biogas.

This study investigated the hydrogen mass transfer limitations in a biotrickling filter inoculated with hydrogenotrophic methanogens for biogas upgrading. A highly sensitive dissolved hydrogen probe allowed measuring concentrations in real-time. Experiments were conducted to test the mass transfer resistance in the gas and liquid films.

Reduction in energy for electrochemical disinfection of in urine simulant.

Abstract: We report the development of novel modes of operation for electrochemical disinfection of in human urine simulant with an aim to minimize the energy required for disinfection. The system employs boron-doped diamond electrodes and will be part of an energy neutral, water and additive free outdoor toilet being developed for use in developing countries. Disinfection had been previously demonstrated with voltage being continuously applied to the electrode until disinfection was achieved.

Miniaturized Biotrickling Filters and Capillary Microbioreactors for Process Intensification of VOC Treatment with Intended Application to Indoor Air.

Typical biofilters and biotrickling filters used for volatile organic compounds (VOCs) control have treatment rates limited to 30-200 g m h, mostly because they are exposed to dilute VOC streams, have moderate biomass density and activity, and moderate mass transfer coefficients. For these reasons and the concern over releasing bioaerosols and humidity, traditional biofilters and biotrickling filters are not ideal for the treatment of indoor air. Here we report on the development and evaluation of microbioreactors for the intensive treatment of VOCs that could be used for indoor air quality control, when coupled with a VOC microconcentrator (developed separately).

Bioaerosol emissions associated with pit latrine emptying operations.

Pit latrines are the most common sanitation option in the developing world. They are simple to build but require periodic emptying which results in widespread dispersion of fecal pathogens in the environment. While much is known about the health risks of fecal-oral exposure, little is known about those resulting from the aerosolization of pathogens from fecal material.

Quantification of Mercury Bioavailability for Methylation Using Diffusive Gradient in Thin-Film Samplers.

Mercury-contaminated sediment and water contain various Hg species, with a small fraction available for microbial conversion to the bioaccumulative neurotoxin monomethylmercury (MeHg). Quantification of this available Hg pool is needed to prioritize sites for risk management. This study compared the efficacy of diffusive gradient in thin-film (DGT) passive samplers to a thiol-based selective extraction method with glutathione (GSH) and conventional filtration (<0.