Treatment technology for leachate from faecal sludge drying beds

The use of planted drying beds for faecal sludge treatment is effective for solid-liquid separation, but the leachate produced requires further treatment prior to discharge or reuse. This study investigates the potential of a new and low-cost solution for leachate treatment

Whole-thorax irradiation induces hypoxic respiratory failure, pleural effusions and cardiac remodeling

To study the mechanisms of death following a single lethal dose of thoracic radiation, WAG/RijCmcr (Wistar) rats were treated with 15 Gy to the whole thorax and followed until they were morbid or sacrificed for invasive assays at 6 weeks. Lung function was assessed by breathing rate and arterial oxygen saturation. Lung structure was evaluated histologically. Cardiac structure and function were examined by echocardiography. The frequency and characteristics of pleural effusions were determined. Morbidity from 15 Gy radiation occurred in all rats 5 to 8 weeks after exposure, coincident with histological pneumonitis. Increases in breathing frequencies peaked at 6 weeks, when profound arterial hypoxia was also recorded. Echocardiography analysis at 6 weeks showed pulmonary hypertension and severe right ventricular enlargement with impaired left ventricular function and cardiac output. Histologic sections of the heart revealed only rare foci of lymphocytic infiltration. Total lung weight more than doubled. Pleural effusions were present in the majority of the irradiated rats and contained elevated protein, but low lactate dehydrogenase, when compared with serum from the same animal. Pleural effusions had a higher percentage of macrophages and large monocytes than neutrophils and contained mast cells that are rarely present in other pathological states. Lethal irradiation to rat lungs leads to hypoxia with infiltration of immune cells, edema and pleural effusion. These changes may contribute to pulmonary vascular and parenchymal injury that result in secondary changes in heart structure and function. We report that conditions resembling congestive heart failure contribute to death during radiation pneumonitis, which indicates new targets for therapy

Thrombin increases inflammatory cytokine and angiogenic growth factor secretion in human adipose cells in vitro

<p>Abstract</p> <p>Background</p> <p>Abdominal obesity is associated with pro-thrombotic and inflammatory states. Therefore, the purpose of this study was to examine the expression of thrombin receptors (PAR1 and PAR4) human adipose tissue and whether thrombin stimulates an inflammatory cytokine and growth factor profile in human adipose tissue.</p> <p>Methods</p> <p>Human adipose tissue, isolated preadipocytes and differentiated adipocytes were used in this study. PAR1 and PAR4 mRNA and protein were detected by RT-PCR and immunoblot analysis in both adipose tissue and adipose microvessels. In separate studies, IL-1β, IL-6, MCP-1, TNF-α, IL-10, FGF-2, VEGF, and PDGF production were measured from adipose tissue (n = 5), adipocytes (n = 5), and preadipocytes (n = 3) supernatants with and without thrombin (1 or 10 U/ml; 24 hrs) treatment.</p> <p>Results</p> <p>Thrombin increased cytokine secretion of IL-1β, IL-6, MCP-1 and TNF-α and growth factor secretion of VEGF from adipocytes along with MCP-1 and VEGF from preadipocytes. The direct thrombin inhibitor lepirudin given in conjunction with thrombin prevented the thrombin-mediated increase in cytokine and growth factor secretion.</p> <p>Conclusion</p> <p>Here we show that thrombin PAR1 and PAR4 receptors are present and that thrombin stimulates inflammatory cytokine generation and growth factor release in human adipose tissue and cells <it>in vitro</it>. These data suggest that thrombin may represent a molecular link between obesity and associated inflammation.</p

Effect of filter media thickness on the performance of sand drying beds used for faecal sludge management

The effect of sand filter media thickness on the performance of faecal sludge (FS) drying beds was determined in terms of: dewatering time, contaminant load removal efficiency, solids generation rate, nutrient content and helminth eggs viability in the dried sludge. A mixture of VIP-latrine sludge and septage in the ratio 1:2 was dewatered using three pilot-scale sludge drying beds with sand media thicknesses of 150 mm, 250 mm and 350 mm. Five dewatering cycles were conducted and monitored for each drying bed. Although 150 mm filter had the shortest average dewatering time of 3.65 days followed by 250 mm and 350 mm filters with 3.83 and 4.02 days, respectively, there was no significant difference ( p > 0.05) attributable to filter media thickness configurations. However, there was a significant difference for the percolate contaminant loads in the removal and recovery efficiency of suspended solids, total solids, total volatile solids, nitrogen species, total phosphorus, COD, DCOD and BOD, with the highest removal efficiency for each parameter achieved by 350 mm filter. There were also significant differences in the nutrient content (NPK) and helminth eggs viability of the solids generated by the tested filters. Filtering media configurations similar to 350 mm have the greatest potential for optimising nutrient recovery from FS

Algal diversity and distribution in Waste Stabilization Ponds treating faecal sludge leachate from drying vegetated beds

Waste Stabilization Ponds (WSP) were tested at pilot scale for the polishing of faecal sludge leachate from planted drying beds in Yaoundé, Cameroon. Water was sampled at three different depths (10, 30, 45 cm) and three different hydraulic retention times (HRT) (4, 7 and 10 days) in two  maturation basins in series for physico-chemical and biological analyses. As a removal mechanism, algae diversity, density and biomass were assessed and correlated to the physical parameters within the ponds. Results showed the presence of nine algal species belonging to three divisions, four classes, six orders, eight families and eight genera. Among these species found in WSPs, Chlamydomonas globosa, Monoraphidium convolutum and pseudanabaena catena were the most abundant whatever the basin, the hydraulic retention time (HRT) and depth. PO4P, NH4N andthe total chlorophyll showed strong correlation with the algal biomass (0.582, 0.731 and 0.895 respectively) at the surface (0-15 cm) followed by TSS, temperature and COD (0.556, 0.509 and 0.533 respectively) at HRT 4days. These correlations were not observed at HRT 7 and 10 days.Keywords: Algal dynamic, Waste Stabilization Pond, faecal sludge leachate, depth, hydraulic retention time

The Interaction of Photoactivators with Proteins during Microfabrication

Micron-scale protein cross-linking or microfabrication has been carried out using an Nd3+–YAG laser as the excitation source. Fabrication is carried out by the excitation of photoactivators (Rose Bengal, methylene blue and 9-fluorenone-2-carboxylic acid) with the ultimate goal of creating stable structures that will serve as models for various applications (drug delivery and tissue engineering). Experimental parameters have been adjusted to minimize photodamage and maximize cross-linking efficiency. The higher than ideal photon flux and peak power necessitates the use of high protein concentrations to minimize photodamage. Rose Bengal and methylene blue are binding to proteins with high association constants (Ka ≈ 106 M−1) and both Rose Bengal and both 9-fluorenone-2-carboxylic acid are showing changes to their excited states in presence of proteins at cross-linking concentrations. Molecular docking studies show that Rose Bengal binds close to the tryptophan with ΔG = −6.15 kcal/mol

Technologies for sanitation: how to determine appropriate sludge treatment strategies in Vietnam

Developing appropriate technologies for the sanitation chain in low- and middle-income countries is crucial to protect public and environmental health. This includes treatment systems for the sludge produced in onsite and centralized systems (i.e., faecal and wastewater sludge). As the quantities and characteristics of sludge differ from city to city, this requires context-specific technologies. This case study was conducted to identify potential management strategies in five cities in Vietnam. The influence of the enabling environment, existing infrastructures, local sanitation practices and socioeconomic contexts on the selection of technology was assessed through literature reviews, household surveys and interviews. A checklist of influential aspects is presented to make best use of local opportunities and minimize the risks of technology failure. This approach is applicable to develop sludge management strategies in other cities

FAQ: faecal sludge quantification and characterization - field trial of methodology in Hanoi, Vietnam

Characterizing and quantifying faecal sludge (FS) at a city-wide scale in low- and middle-income countries is essential for designing and planning appropriate FS treatment facilities. However, there currently is no accurate methodology for the estimation of these values. The FAQ (faecal sludge quantification and characterization) study developed a methodology, and is validating it in Hanoi, Vietnam and Kampala, Uganda. The method utilizes spatially analysed demographic data as a predictor of FS characteristics. Extensive sampling has been conducted to field test the presented method. This paper presents results of collected and analysed secondary data, and preliminary results of the TS, VS, COD and SCOD concentrations from household septic tanks in Hanoi, which were on average 26,471, 19,395, 37,541 and 713 mg/L respectively, and ongoing data analysis is being conducted