Microbial contamination remains a major challenge in drinking water supplies in developing regions, despite the continuous advances being made in water purification processes. The spread and transmission of pathogens due to consuming unsafe water culminate in waterborne diseases and increased number of deaths worldwide. Recently, the application of nanotechnology for water purification, and in particular the use of antibacterial nanoparticles (NPs) to control microbial contaminations, has received considerable interest. In this study, antibacterial chitosan−silver nanoparticles (CS/AgNPs) were enzymatically grafted on cork matrixes to design a water purification point-of-use device. The antibacterial efficiency of the constructed filtering system was further evaluated against water severely contaminated with Escherichia coli (∼10 7 CFU/mL). The system was tested in two operating filtration modes with varied water residence times. The antibacterial nanocomposite decreased the water bacterial contamination by 4 and 5 log CFU/mL when performing a series of continuous short disinfection cycles of 15 min residence time (experiment I). Nevertheless, complete bacteria removal was achieved only after increasing the water residence time in the filters up to 8 h (experiment II). Durability of the system was demonstrated via performing five disinfection cycles after which the hybrid CS/AgNPs remained on the cork surface. Importantly, the antibacterial nanocomposite prevented bacteria attachment and proliferation during all cycles of the disinfection process.

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Thermal characterization of coffee husk (Coffea arabica) from Colombian coffee has been studied. Different products, mostly volatile and semi-volatile compounds, were analyzed paying special attention to 16 polycyclic aromatic hydrocarbon classified by Environmental Protection Agency (EPA) as priority pollutants, frequently used for checking toxicity in environmental samples. Fixed amount of raw material was

The most efficient system of horizontal subsurface flow constructed wetlands (HSSFCW) for removing dissolved organic carbon (DOC) in the presence of chlorothalonil pesticide (CLT) present in synthetic domestic wastewater was determined using the macrophyte Phragmites australis. Two concentrations of CLT (85 and 385 μg L) and one concentration of glucose (20 mg L) were evaluated in four pilot scale horizontal surface flow constructed wetlands coupled with two sizes of silica gravel, igneous gravel, fine chalky gravel (3.18-6.35 mm), coarse gravel (12.70-25.40 mm) and two water surface heights (20 and 40 cm). For a month, wetlands were acclimated with domestic wastewater. Some groups of bacteria were also identified in the biofilm attached to the gravel. In each treatment periodic samplings were conducted in the influent and effluent. Chlorothalonil was quantified by gas chromatography (GC-ECD m), DOC by an organic carbon analyzer and bacterial groups using conventional microbiology in accordance with Standard Methods. The largest removals of DOC (85.82%-85.31%) were found when using fine gravel (3.18-6.35 mm) and the lower layer of water (20 cm). The bacterial groups quantified in the biofilm were total heterotrophic, revivable heterotrophic, Pseudomonas and total coliforms. The results of this study indicate that fine grain gravel (3.18-6.35 mm) and both water levels (20 to 40 cm) can be used in the removal of organic matter and for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT in HSSFCW.