Public concern on the groundwater contamination by nitrate has grown significantly in recent years. The objective of this study was to determine the appropriate treatment to reduce the nitrate content in the presence of other ions from groundwater, for which nanofiltration and ion exchange were evaluated. In nanofiltration, the effects of pressure, feed flow, initial composition, and performance were studied, in ion exchange the flow rate, initial composition, and resin regeneration process. Nanofiltration tests were carried out on four different commercial membranes NF97, NF99, NF99H, and NF90. Among these, all membranes removed chloride but only NF97 and NF90 were able to remove nitrate in compliance with Chilean drinking water standard, showing rejections of 97% and 87%, respectively, in an optimum pressure range of 12-20 bar in which the NF90 produced 3.5 times more permeated water than NF97. For ion exchange tests, Purolite A520E resin was used, which decreased nitrate content to less then 1 mg/L. Results leading to the optimal flow within the exchange column indicated that residence time must be at least 2.1 min. The higher nitrate concentration in water did not lead to changes in the maximum resin capacity, 47.1 mg NO3-/g resin, but it did decrease the resin breakthrough capacity when initial concentration increased. Optimal regeneration was assigned to a 3% w/V NaCl solution and up-flow mode. Due to the ability to remove both nitrate and chloride, and being able to remove iron if necessary, nanofiltration was chosen as the appropriate treatment. BACKGROUND Daily air quality index (AQI) forecast can provide early warning information, and it is not clear whether it is appropriate for childhood asthma hospitalizations (CAHs). Furthermore, little is known about the effects of AQI on CAHs, as well as the interactions between temperature, humidity and AQI. Mcl-1 apoptosis METHODS We collected 32,238 cases in Hefei from 2013 to 2016 and estimated the association between daily CAHs and AQI by combining the Poisson Generalized Linear Models (PGLMs) with the Distributed Lag Nonlinear Models (DLNMs). The interaction between AQI and temperature was tested by stratifying AQI and temperature, as well as humidity. RESULTS AQI was associated with an increased risk of hospitalizations for childhood asthma. The adverse effect first appeared on the 3rd day, with the RR of 1.011 (95%CI 1.000-1.023) and continued until the 19th day of lag (RR = 1.010, 95%CI 1.001-1.020). In the subgroup analysis, the male and pre-school children were more sensitive to AQI, and there are seasonal differeenough to strengthen the prevention of childhood asthma hospitalization. Biochar is a product of biomass thermochemical conversion. Its yield and quality vary significantly with the production technology and process parameters, which also affect its performance in agro and forestry systems. In this review, biochar production technologies including slow pyrolysis, fast pyrolysis, gasification, and torrefaction were compared. The yield of biochar was found to decrease with faster heating rate or more oxygen available. The benefits of biochar application to agro and forestry systems were discussed. Improvements in soil health, plant growth, carbon sequestration, and greenhouse gas mitigation are apparent in many cases, but opposite results do exist, indicating that the beneficial aspect of biochar are limited to particular conditions such as the type of biochar used, the rate of application, soil type, climate, and crop species. Limitations of current studies and future research needed on biochar are also discussed. Specifically, the relationships among biochar production technologies, biochar properties, and biochar performance in agro and forestry systems must be better understood. A new composite material (Fe3O4@GAC, Fe3O4 nanoparticles loaded on a commercial granular activated carbon (GAC)) was prepared through a facile hydrothermal process at controlled Fe2+Fe3+ molar ratios in air. Fe3O4@GAC was thoroughly characterized and tested for adsorption of perfluorooctanoic acid (PFOA) in water. Fe3O4@GAC(21), prepared at an Fe2+Fe3+ molar ratio of 21, showed the best PFOA removal and offered 28.8% higher adsorption capacity than the parent GAC at final pH 4.0. The enhanced adsorption of PFOA was attributed to concurrent hydrophobic, electrostatic and complexation interactions between PFOA, GAC and Fe3O4. GAC in the composite played an important role for PFOA adsorption. The presence of Ca2+ ions (10 mM) at final pH 5.0-10.0 more than doubled the PFOA equilibrium uptake of PFOA by Fe3O4@GAC(21) due to the calcium bridging effect between PFOA and the Si-OH or Fe-OH groups in Fe3O4@GAC(21), and because of the Ca2+-modification induced formation of PFOA hemi-micelles on the surface or in the relatively large pores (2.27 nm) of Fe3O4@GAC(21). Fe3O4@GAC(21) was amenable to efficient regeneration using a mixture of NaOH solution and methanol. Fe3O4@GAC holds the potential to be used as a simple and low-cost adsorbent for enhanced adsorption of PFOA, especially in waters of high hardness and alkalinity. V.The early stages of the fish life cycle correspond to the phase that is most susceptible to deleterious effects caused by exposure to pollution. The aim of this study was to evaluate the quality of the anaerobic reactor effluent after three filtration-based treatments, namely, Double-Filtration in gravel and sand (DF), Triple-Filtration in gravel, sand and Activated Charcoal (TF-AC) and Triple-Filtration in gravel, sand and clinoptilolite (TF-C). The toxic effects on the population dynamics of larvae and embryos of catfish (Rhamdia quelen) to the final effluent were evaluated using an individual-based model (IBM). The results indicate that the three post-treatments produced effluents with significant improvement of the physicochemical parameters evaluated in relation to the anaerobic reactor effluent. In addition, all post-treatments improved the removal of metal ions. Experimental data showed high mortality rates for Rhamdia quelen embryos and larvae for most treatments, except for the effluent treated by TF-C.