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Understanding the excretion and treatment of human waste (feces and urine) in low and middle income countries (LMICs) is necessary to design appropriate waste management strategies. However, excretion and treatment are often difficult to quantify due to decentralization of excreta management. We address this gap by developing a mechanistic, stochastic model to characterize phosphorus, nitrogen, biochemical oxygen demand (BOD), and fecal coliform pollution from human excreta for 108 LMICs. The model estimates excretion and treatment given three scenarios: (1) use of existing sanitation systems, (2) use of World Health Organization-defined "improved sanitation", and (3) use of best available technologies. Our model estimates that more than 109 kg/yr each of phosphorus, nitrogen and BOD are produced. Of this, 22(19-27)%, 11(7-15)%, 17(10-23)%, and 35 (23-47)% (mean and 95% range) BOD, nitrogen, phosphorus, and fecal coliforms, respectively, are removed by existing sanitation systems. Our model estimates that upgrading to "improved sanitation" increases mean removal slightly to between 17 and 53%. Under the best available technology scenario, only approximately 60-80% of pollutants are treated. To reduce impact of nutrient and microbial pollution on human and environmental health, improvements in both access to adequate sanitation and sanitation treatment efficiency are needed. [ABSTRACT FROM AUTHOR]

The city of New Orleans, LA was severely impacted by flooding and wind damage following landfall of Hurricane Katrina in August 2005. The city's drinking water infrastructure was severely compromised and massive amounts of sediment were redeposited throughout the flooded region. Thousands of homes were water-damaged resulting in the rapid growth of mold. In September and October 2005 a convenience sample of selected homes, tap water, surface water, and sediment within New Orleans was assessed for mold contamination, microbial contamination, and heavy metal concentrations. At selected sites, indoor mold spore concentrations were compared to outdoor concentrations. The purpose of this study was to conduct a baseline environmental assessment in an effort to identify public health threats caused by wind and flood damage. Surface waters contained high concentrations of bacterial indicators whereas no bacteria were detected in tap water, even from taps containing no chlorine residual. Sediment samples contained concentrations of lead and arsenic similar to pre-Katrina concentrations. Outdoor total spore (sp) concentrations ranged from >6500 to 84 713 sp/m³. Indoor concentrations ranged from 6142 to 735 123 sp/m³. For the 13 locations with matched indoor/outdoor samples, the mean indoor/outdoor spore ratio was 4.11 (ranging from 0.27 to >11.44). Inside 5 of the 13 homes, total spore counts/m³ exceeded 100 000, with measurements in the moldiest home exceeding 700 000 sp/m³. In conclusion, surface waters had high concentrations of bacterial contamination but no bacterial indicators were present in tap water. Sediment samples did not have appreciable increases in lead or arsenic. Flooded homes, however, contained substantial concentrations of mold which could present a public health exposure route to individuals repopulating and restoring the City of New Orleans. [ABSTRACT FROM AUTHOR]

Colloidal natural organic matter (NOM) is an important foulant to low-pressure membranes (LPMs) employed in drinking water treatment. Removal of colloidal NOM by magnetic ion exchange (MIEX), coagulation, and integrated MIEX and coagulation was investigated in this study to determine the relationship between colloidal NOM removal and membrane fouling reduction. The results showed that coagulation did not selectively remove colloidal NOM and the optimal coagulant dose was primarily determined by the concentration of humic substances. Comparatively, MIEX pretreatment preferentially removed humic substances and reduced the coagulant dose needed for colloidal NOM removal as a result of coagulation stoichiometry. A matched-pair analysis showed that integrated MIEX and coagulation pretreatment at much lower coagulant doses was as effective as coagulation in reducing membrane fouling. It is concluded that integrated MIEX and coagulation is potentially a viable pretreatment approach to reduce membrane fouling and in general removal of colloidal NOM in feedwater is an effective approach for membrane fouling control and should be considered in the research, development, and application of novel LPM-based treatment processes.

Exposure assessment of biological aerosols requires trade-offs between efficient sampling of airborne microorganisms as either particles or viable units. The main objective of this work was to characterize aspects of bioaerosol measurement efficiency. A known concentration of the vegetative bacteria Pantoea agglomerans was spiked onto different samplers (AGI-30, BioSampler, and membrane filters) and then run for increasing time periods using HEPA filtered air. Measurement efficiency was evaluated based on total, viable, and culturable counts. Total and viable counts were determined by flow-cytometry (FCM); culturable counts were evaluated by standard plating. FCM as a method for assaying viability showed excellent agreement with known proportions of live/dead organisms (slope = 0.82, R(2) = 0.99). P. agglomerans recoveries (total, viable, and culturable) in order of best sampler performance included the BioSampler (75%, 52%, and 50%), filtration (50%, 13%, and 2%), and the AGI-30 (<30%, 15%, and 5%). The difference between viability and culturability provided an indication of viable but nonculturable (VBNC) cells. VBNC efficiency for sampling by filter, AGI-30, and BioSampler was 80%, 50%, and 100%, respectively. This research helps characterize recovery, survival, and culturability efficiencies while sampling environmentally sensitive airborne bacteria for purposes of exposure assessment, epidemiologic studies, and homeland security.

Poor air quality within swine concentrated animal feeding operations (CAFOs) poses a threat to workers, the surrounding community, and farm production. Accordingly, the current study was conducted to evaluate a technology for reducing air pollution including particulate matter (PM), viable bacteria, and ammonia within such a facility. The technology consists of an acid-oil-alcohol aerosol applied daily. Its effectiveness was evaluated by comparing air quality from before to after treatment and between treated and untreated sides of a barn separated by an impervious partition. On the untreated side, air quality was typical for a swine CAFO, with mean PM2.5 of 0.28 mg/m3 and PM(TOT) of 1.5 mg/m3. The treatment yielded a reduction in PM concentration of 75-90% from before to after treatment. Effectiveness increased with time, application, and particle size (40% reduction for 1 microm and 90% for >10 microm). Airborne bacteria levels (total bacteria, Enterobacteriaceae, and gram-positive cocci) decreased one logarithmic unit after treatment. In contrast, treatment had no effect on ammonia concentrations. These findings demonstrate the effectiveness of an intervention in yielding exposure and emission reductions.