The concentration levels of 36 airborne heavy metals and atmospheric radioactivity in total suspended particulate (TSP) samples were measured to investigate the chemical characteristics, potential sources of aerosols, and health risk in Beijing, China, from September 2016 to September 2017. The TSP concentrations varied from 6.93 to 469.18 μg/m3, with a median of 133.97 μg/m3. The order for the mean concentrations of heavy metals, known as hazardous air pollutants (HAPs), was as follows: Mn > Pb > As > Cr > Ni > Se > Cd > Co > Sb > Hg > Be; Non-Designated HAPs Metals: Ca > Fe > Mg > Al > K > Na > Zn > P > Ba > Ti > Cu > Sr > B > Sn > I > V > Rb > Ce > Mo > Cs > Th > Ag > U > Pt. The median concentration of As was higher than China air quality standard (6 ng/m3). The gross α and β concentration levels in aerosols were (1.84?±?1.59) mBg/m3 and (1.15?±?0.85) mBg/m3, respectively. The enrichment factor values of Cu, Ba, B, Ce, Tl, Cs, Pb, As, Cd, Sb, Hg, Fe, Zn, Sn, I, Mo, and Ag were higher than 10, which indicated enriched results from anthropogenic sources. Pb, As, and Cd are considered to originate from multiple sources; fireworks released Ba during China spring festival; Fe, Ce, and Cs may come from stable emissions such as industrial gases. The health risks from anthropogenic metals via inhalation, ingestion, and dermal pathway were estimated on the basis of health quotient as well as the results indicated that children faced the higher risk than adults during the research period. For adults, the health risk posed by heavy metals in atmospheric particles was below the acceptable level.
Industrial wastewater typically contains various metal ions. Traditional metal ion treatment processes such as chemical precipitation generate large volumes of toxic sludge which needs to be further solidified or disposed of. The ferrite process (FP), which is another effective approach of treating metal ion-containing wastewater, can crystallize metal ions into ferrites; the sludge easily precipitates, is stable and can be recycling. This investigation explores the feasibility of the Fenton process and the FP (FFP) for treating wastewater that contains metal ions. It considers one factor that adds noise to the FP, ethylenediaminetetraacetic acid, and establishes the optimum parameters of each procedure. The analytical results demonstrate that the proper conditions for Fenton process were pH = 2, [Fe(2+)] = 10(-2) M, H(2)O(2) dosing rate = 5 x 10(-4) mol min(-1), reaction time = 12 min. For the proposed multi-stage FP, the preferred Fe(2+) dosage was 0.098 mol in each stage and the sludge met the toxicity characteristic leaching procedure standards. Following the FFP, the effluent water or the sludge easily met Taiwan's standards. Finally, the SEM test demonstrated that size of the sludge particles was 50-110 nm. 相似文献
Wastewater reuse can significantly reduce environmental pollution and save the water sources. The study selected Cheng-Ching
Lake water treatment plant in southern Taiwan to discuss the feasibility of wastewater recycling and treatment efficiency
of wastewater treatment units. The treatment units of this plant include wastewater basin, sedimentation basin, sludge thickener
and sludge dewatering facility. In this study, the treatment efficiency of SS and turbidity were 48.35–99.68% and 24.15–99.36%,
respectively, showing the significant removal efficiency of the wastewater process. However, the removal efficiencies of NH3–N, total organic carbon (TOC) and chemical oxygen demand (COD) are limited by wastewater treatment processes. Because NH3–N, TOC and COD of the mixing supernatant and raw water are regulated raw water quality standards, supernatant reuse is feasible
and workable during wastewater processes at this plant. Overall, analytical results indicated that supernatant reuse is feasible. 相似文献
Nonylphenol (NP) is a representative environmental endocrine-disrupting chemical and persistent toxic pollutant. Previous studies have shown that the average concentration of NP in environmental waters was approximately tens to hundreds of ng L(-1) and it could even reach up to tens of μg L(-1). A simple, fast and accurate method employing a novel solid-phase extraction element named "Magic Chemisorber" (MC) followed by high-performance liquid chromatography (HPLC) using a fluorescence detector (FLD) was used for detecting NP. The most important parameters that affect the extraction process, including extraction time, desorption time, desorption solvent and repeatability, were optimized. The MC-HPLC method showed good linearity with concentrations of NP from 10 to 200 μg L(-1), a correlation coefficient of 0.9995 and the limit of detection (LOD) and limit of quantification (LOQ) of this method was 0.44 and 1.47 μg L(-1), respectively. Compared to commercial polydimethylsiloxane (PDMS) glass fiber, MC had both higher capacity and recovery and it could be used repeatedly. Using the MC-HPLC method we found that the concentration of NP in river water from Hangzhou city ranged from 8.54 ± 1.23 μg L(-1) (Qiantang River) to 65.77 ± 3.69 μg L(-1) (Tiesha River), which was similar to that of international regions heavily polluted with NP and higher than that of Bohai Bay, the Yellow River and the Pearl River Delta in China. This level of NP pollution is possibly related to the rapid development of the textile, printing and paper industries of Zhejiang province. 相似文献
Stability of drinking water can be indicated by the assimilable organic carbon (AOC). This AOC value represents the regrowth
capacity of microorganisms and has large impacts on the quality of drinking water in a distribution system. With respect to
the effectiveness of traditional and advanced processing methods in removing trace organic compounds (including TOC, DOC,
UV254, and AOC) from water, experimental results indicate that the removal rate of AOC at the Cheng Ching Lake water treatment
plant (which utilizes advanced water treatment processes, and is hereinafter referred to as CCLWTP) is 54%, while the removal
rate of AOC at the Gong Yuan water treatment plant (which uses traditional water treatment processes, and is hereinafter referred
to as GYWTP) is 36%. In advanced water treatment units, new coagulation–sedimentation processes, rapid filters, and biological
activated carbon filters can effectively remove AOC, total organic carbon (TOC), and dissolved organic carbon (DOC). In traditional
water treatment units, coagulation–sedimentation processes are most effective in removing AOC. Simulation results and calculations
made using the AutoNet method indicate that TOC, TDS, NH3-N, and NO3-N should be regularly monitored in the CCLWTP, and that TOC, temperature, and NH3-N should be regularly monitored in the GYWTP. 相似文献