Blakegraversen3461

Moreover, we measured elevated ammonium levels and rapid cycling of ammonium and dissolved organic nitrogen in Victoria Harbour suggesting local sources, such as wastewater, might be rapidly oxidized and thus play an important role in the consumption of oxygen locally. A first-order calculation highlighted the potential for wastewater to drive the observed seasonal decline in oxygen. Taken together, these evidences suggest that eutrophication might not be the primary driver in the generation of seasonal hypoxia and that oxidation of ammonium released locally might play a bigger role than initially thought.In this study, two lab-scale Moving Bed Membrane Bioreactors (MBMBR) were setup and operated in parallel to study the effect of coarse and fine bubble aeration on the performances of membrane filtration and denitrification treating domestic wastewater. Temsirolimus manufacturer The bacterial populations in the two MBMBRs were further analyzed to investigate the mechanisms involved in the different denitrification performances. The results showed that coarse bubble aeration could effectively mitigate membrane fouling by decreasing the formation of cake layer, although smaller sizes of bio-flocs were induced. In addition, coarse bubble aeration could also maintain dissolved oxygen (DO) at a relatively lower level without compromising the moving of bio-carriers, which achieved 10% higher total nitrogen removal rate due to anoxic zone created at inner layers of biofilms on bio-carriers. Accumulation of denitrifier (Thiobacillus denitrificans) on the bio-carriers was found under the coarse bubble aeration system, which can explain its superior denitrification performance.Risk assessment is considered an essential tool to assist in the management and mitigation of polluted areas, especially those associated with economic activities that significantly degrade the environment, such as mining. However, most of the methodologies of risk assessment adopt the deterministic approach of using a fixed value for ascertaining the hazards derived from exposure to chemical pollutants. However, this is not the case of the Human, Ecological and Radiological Risk (HERisk) code, which allows space-time assessments of ecological, radiological, and human health risks. Indeed, this work aims to describe this new software (enhanced version of HHRISK), which not only improves the performance of the code but also increases its applicability and versatility. To showcase its usefulness in evaluating ecological pollution and human health risk were studied the contents of potentially toxic elements (Co, Cu, Fe, Mn, Ni, Pb, and Zn) in soils and surface waters from the nickel mining area in the municipality of Itagibá (Bahia, Brazil). The obtained results showed that metals are non-homogeneous distributed, suggesting the presence of local enrichment sources, mainly related to human activities. The statistical analyses carried out revealed that mining and agricultural activities are possibly responsible for the contents of these pollutants in both soils and surface waters. The calculated ecological indices of pollution confirmed anthropogenic pollution around the mining area, especially in the locations closest to sterile waste piles. The results of the human health risk assessment revealed that the ingestion of meat and contaminated water are the main routes for entering the potentially toxic elements to the human body and that Co is the chemical specie that poses the highest risk in the entire region. The hazard index (HI) values indicated that the whole area around the mine should be considered as a high risk for human health.In view of the problems involved in remote sensing monitoring of urban air quality, including low spatial resolution, only for a single pollutant, complex inversion algorithms, and difficultly obtaining parameter values, in this study, a new difference smog index (DSI) was developed, and then a comparison with the normal difference haze index, the difference index, and the MODIS aerosol optical depth products. The results show that the DSI model developed in this study has a higher accuracy and a better monitoring effect in urban areas, and it has a higher resolution (30 m), which greatly improves the degree of refinement of the remote sensing monitoring. The DSI model has a higher extensibility, and it is suitable for monitoring the AQI, PM2.5, NO2. The DSI model proposed in this paper is simple and easy to use, and thus, it has a high potential for application and deserves promotion in urban air quality monitoring.Constructed wetland treatment systems (CWTS)s can be used to treat various wastewaters. The main constituent in oil sands process-affected water (OSPW) with uncertain treatment by CWTS are naphthenic acid fraction compounds (NAFC)s. The NAFCs are also among the primary contributors of toxicity to aquatic organisms. While there is preliminary evidence that some CWTSs are capable of treating OSPW for future potential discharge, there is little information comparing the effectiveness and efficiencies of different CWTS designs. Obtaining large volumes of OSPW for testing can be difficult, and while it is known that synthetic NAFCs are simpler and have different toxicity than OSPW-NAFCs, it is unknown whether they could serve as a proxy for optimization of CWTS design and operation. This study presents a comprehensive comparison of CWTS performance operated with both synthetic OSPW and OSPW for four CWTS designs differing in plant type, aeration, flow path, water depth, and substrate type. This study evaluated the potential biodegradation of NAFCs including (1) decrease in total NAFC concentration, (2) shifts in Ox-NAFC fractions from O2- to O3-, O4-, and O5-NAFC, (3) decrease in carbon number, (4) decrease of the double bond equivalencies (DBE), and (5) change in toxicity of the waters to test organisms. CWTS planted with Sedge achieved the greatest extent of NAFC treatment and detoxification regardless of design. Although CWTSs planted with Cattail and Bulrush also degraded NAFCs and decreased toxicity, a greater hydraulic retention time was required, and the total extent of treatment was less than the CWTSs planted with Sedge. While synthetic OSPW was more toxic and experienced faster degradation rates, it showed similar trends to OSPW in terms of CWTS design efficiencies and function. Although synthetic OSPW would not be appropriate for modelling or scaling of CWTSs, it can be useful for testing designs and operating conditions.