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Field test of SO3 removal in ultra-low emission coal-fired power plants Full text
2020
Zhang, Yang | Zheng, Chenghang | Hu, Fushan | Zhao, Haitao | Liu, Shaojun | Yang, Zhengda | Zhu, Yue | Gao, Xiang
Under the extensive implementation of ultra-low emission (ULE) facilities in coal-fired power plants of China, sulfur trioxide (SO₃) has received increasing attention due to its impact on human health and operation safety of power plants. However, systematic research and evaluation for controlling SO₃ emission in various ULE facilities are still lacking. Here, a systematic study was conducted based on 378 in situ performance evaluation tests carried out in 148 coal-fired power plants. The results illustrate that the SO₂/SO₃ conversion rate of the selective catalytic reduction devices can be controlled within 1% before and after ULE retrofit. Also, the synergistic removal efficiency of SO₃ in the low-low-temperature electrostatic precipitator and the wet electrostatic precipitator can be higher than 70%. The removal efficiency of SO₃ in the wet limestone-gypsum flue gas desulfurization scrubber is 33–64% before ULE and 31–81% after, and the average efficiency of the double scrubbers is 8.7% higher than that of the single scrubber. Due to the different SO₃ removing abilities of various technologies, the overall efficiency of SO₃ removal is in the range between 27 and 95% adopting different ULE technical routes. Average concentration of SO₃ emission can be decreased by 51.8% after ULE application.
Show more [+] Less [-]Combined use of calcium nitrate, zeolite, and anion exchange resin for controlling phosphorus and nitrogen release from sediment and for overcoming disadvantage of calcium nitrate addition technology Full text
2020
Zhan, Yanhui | Wu, Xiaolong | Lin, Jianwei
Ca(NO₃)₂ addition has proved to have a high potential to immobilize internal phosphorus (P) in sediments; however, it cannot effectively stop the release of ammonium-nitrogen (NH₄⁺-N) from sediments into overlying waters (OL-waters). Additionally, the addition of Ca(NO₃)₂ alone has high risk of nitrate-nitrogen (NO₃⁻-N) releasing into OL-waters. To overcome the shortcoming of the Ca(NO₃)₂ addition method, we reported an integrated method, i.e., a combined method based on Ca(NO₃)₂ injection, zeolite capping, and anion exchange resin (AERN)–contained floating system suspending (Ca(NO₃)₂/zeolite/AERN). The effectiveness and mechanism of the Ca(NO₃)₂/zeolite/AERN method for simultaneously controlling the release of soluble reactive P (SRP) and NH₄⁺-N were investigated, and the NO₃⁻-N releasing risk of this method was evaluated. It was found that the joint use of Ca(NO₃)₂ injection, zeolite capping, and AERN-contained floating system suspending not only could effectively suppress the release of SRP and NH₄⁺-N from sediments into OL-waters simultaneously, but also had much less risk of NO₃⁻-N releasing into OL-waters as compared to the single Ca(NO₃)₂ injection method and the combined Ca(NO₃)₂/zeolite method. The inhibition of the reductive dissolution of the P-bound Fe(III) oxides/hydroxides by the presence of nitrate and the adsorption of ammonium on the zeolite played very important roles in the interception of SRP and NH₄⁺-N releasing into OL-waters by the Ca(NO₃)₂/zeolite/AERN method. After the sediment remediation using the Ca(NO₃)₂/zeolite/AERN approach, the increase in the content of residual P in the sediment layer of 0–50 mm, the decrease of mobile P in the sediment layer of 0–10 mm, and the increased NH₄⁺-N adsorption capacity for the sediment layer of 0–10 mm would be conductive to the interception of SRP and NH₄⁺-N liberation in the long run. Results of this research suggest a promising application potential of the Ca(NO₃)₂/zeolite/AERN method in the simultaneous control of the release of SRP and NH₄⁺-N from sediments.
Show more [+] Less [-]Investigation of toxic elements in Carassius gibelio and Sinanodonta woodiana and its health risk to humans Full text
2020
Arumugam, Anandkumar | Li, Jian | Krishnamurthy, Prabakaran | Jia, Zhang Xi | Leng, Zhanrui | Ramasamy, Nagarajan | Du, Daolin
Increasing toxic metal content in aquatic products has become a universal burden due to the risks to aquatic organisms and human health associated with the consumption of these products. In this study, toxic metal distribution and accumulation in the organs of fish and bivalve species of economic and culinary importance from the lower reaches of the Yangtze River are examined, and the corresponding health risks are also investigated. In general, the viscera and gill show higher concentration of metals than other tissues. The order of the accumulation sequence of metals in muscle tissue of fish and bivalve is Zn > Cu > Mn > Cr > As > Hg > Pb > Cd and Mn > Zn > Cu > As > Cr > Pb > Cd > Hg respectively. Maximum accumulation of Mn (507.50 μg g⁻¹) and Pb (0.51 μg g⁻¹) in the gill tissues indicates the major uptake of these metals from the water column. According to the Hazard Index (HI) calculations (based on USEPA), the analyzed metals will not cause any harmful health effects to individuals for both normal and habitual fish consumers, except for Hg and As in habitual consumers, if these species are consumed at a larger amount. Compared to the Chinese Food Health Criterion and other international standards (WHO/FAO), metal concentrations in the edible muscle tissues of the studied species are lesser than the acceptable levels and found to be fit for human consumption.
Show more [+] Less [-]Heavy metals and persistent organic pollutants contamination in river, estuary, and marine sediments from Atlantic Coast of Democratic Republic of the Congo Full text
2020
Suami, Robert Bueya | Sivalingam, Periyasamy | Al Salah, Dhafer Mohammed | Grandjean, Dominique | Mulaji, Crispin Kyela | Mpiana, Pius Tshimankinda | Breider, Florian | Otamonga, Jean-Paul | Poté, John
The pollution assessment and the evaluation of potential risks in the Atlantic Coastal Region of the Democratic Republic of the Congo are still very limited. Consequently, the present study investigates for the first time the concentrations of heavy metals and persistent organic pollutants (organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs)) in river, estuary, and marine sediments from this area. The results highlighted high concentrations of Cr, Zn, As, and Pb exceeding the probable effect level (PEL) on aquatic life. Zn was the most dominant element detected at a range of 180–480 mg kg⁻¹ in marine sediment, 132–382 mg kg⁻¹ in estuary sediment, and 121–687 mg kg⁻¹ in river sediment. Total PCBs (∑7 × 4.3) ranged from 1995 to 20,156 μg kg⁻¹, 2013–12,058 μg kg⁻¹, and 1861–36,417 μg kg⁻¹ in marine, estuary, and river sediments, respectively. Total PCBs (∑7 × 4.3) were above PEL for all sediments, suggesting potential adverse effects on benthic organisms. The OCP, PBDE, and PAH levels were low to moderate for all sediments. Taking into consideration, the concentrations of Zn, Pb, PCBs, and DDTs, probable environmental risks, are present.
Show more [+] Less [-]Study on clean heating based on air pollution and energy consumption Full text
2020
Guo, Xiaopeng | Ren, Dongfang | Li, Cunbin
Air pollution in northern China is relatively serious during the winter heating period, which attracts the attention of the state and government, especially in Beijing–Tianjin–Hebei Region. To further explore the issue of air pollutant emission and energy utilization in Beijing–Tianjin–Hebei during the heating season, this paper establishes a panel data model which describes the long-term relationship between air pollutant emission, heating capacity, coal, and power consumption with the data from 2004 to 2017. Based on this, we draw the following conclusions: there is a positive relationship between winter heating capacity and air pollutant emissions, which indicates that the energy consumed by heating will produce atmospheric pollutants. However, the increase of electricity consumption does not necessarily reduce pollution, which means that replacing coal with electricity is not the best way to solve air pollution in heating season, but requires the coordination of multiple energy sources. In addition, there are obvious differences in the analysis results in Beijing, Tianjin, and Hebei. For example, the impact of coal and electricity consumption on pollutant emissions in Beijing is quite different from that in Tianjin and Hebei. The local economic development and energy conditions should be fully taken into account when formulating policies.
Show more [+] Less [-]Phosphorus removal from livestock effluents: recent technologies and new perspectives on low-cost strategies Full text
2020
Zangarini, Sara | Pepè Sciarria, Tommy | Tambone, Fulvia | Adani, Fabrizio
Phosphorus is an essential element in the food production chain, even though it is a non-renewable and limited natural resource, which is going to run out soon. However, it is also a pollutant if massively introduced into soil and water ecosystems. This study focuses on the current alternative low-cost technologies for phosphorus recovery from livestock effluents. Recovering phosphorus from these wastewaters is considered a big challenge due to the high phosphorus concentration (between 478 and 1756 mg L⁻¹) and solids content (> 2–6% of total solids). In particular, the methods discussed in this study are (i) magnesium-based crystallization (struvite synthesis), (ii) calcium-based crystallization, (iii) electrocoagulation and (iv) biochar production, which differ among them for some advantages and disadvantages. According to the data collected, struvite crystallization achieves the highest phosphorus removal (> 95%), even when combined with the use of seawater bittern (a by-product of sea salt processing) instead of magnesium chloride pure salt as the magnesium source. Moreover, the crystallizer technology used for struvite precipitation has already been tested in wastewater treatment plants, and data reported in this review showed the feasibility of this technology for use with high total solids (> 5%) livestock manure. Furthermore, economic and energetic analyses here reported show that struvite crystallization is the most practicable among the low-cost phosphorus recovery technologies for treating livestock effluents.
Show more [+] Less [-]Toxic effect of alpha cypermethrin, an environmental pollutant, on myocardial tissue in male wistar rats Full text
2020
Ghazouani, Lakhdar | Feriani, Anouar | Mufti, Afoua | Tir, Meriam | Baaziz, Intissar | Mansour, Hedi Ben | Mnafgui, Kais
α-Cypermethrin (CYP) is a pyrethroid insecticide-like environmental pollutant, widely found in the environment. New research links exposure to high levels of CYP to health damage; however, little is known about the effect of CYP on cardiovascular disease. The purpose of the present study was to evaluate, for the first time, biochemical and cardiovascular changes in male rats resulting from subchronic CYP exposure. The animals were divided into three groups: group 1 served as the control, group 2 (CYP1) received 4 mg/kg of CYP by gavage, and group 3 (CYP2) received 8 mg/kg of CYP by gavage, for 8 weeks each. Results showed that both CYP1 and CYP2 markedly increased plasma concentrations of cardiac markers (LDH, CK-MB, and troponin-T). Moreover, compared to the control group, CYP treatment elevated cardiac oxidative stress, as shown by increased MDA level and decreased activity of SOD, CAT, and GSH-Px. In addition, CYP2 caused a significant increase of 42% the concentration of total cholesterol and more than 75% in triglycerides compared to the control group. Furthermore, DNA fragmentation and collagen deposition were both amplified owing to CYP toxicity. This harmful effect was confirmed by a histological study using H-E and Sirius Red staining. Overall, our results clearly proved the cardiotoxicity caused by α-cypermethrin.
Show more [+] Less [-]Protective effects of Citrus limonia oil against cisplatin-induced nephrotoxicity Full text
2020
Abdel-Daim, Mohamed M. | Mahmoud, Omayma M. | Al Badawi, Manal H. | Alghamdi, Jawahir | Alkahtani, Saad | Salem, Noha A.
Cisplatin is broadly used in the treatment of malignancies. However, the high incidence of nephrotoxicity following cisplatin use deters its clinical utility. Former studies have shown that the essential oils, obtained from Citrus limonia demonstrated significant anti-inflammatory and antioxidant effects. The aim of the current work was to evaluate the protective effects of Citrus limonia oil against cisplatin-induced nephrotoxicity. Thirty-two adult male mice were divided into four groups, eight mice each. The control group received distilled water, and the second group received a single intraperitoneal injection of cisplatin (20 mg/kg), while the third and fourth groups received cisplatin plus Citrus limonia oil at 100 or 200 mg/kg for 10 days, respectively. GC-MS analysis showed that the major components in Citrus limonia oil were D-limonene, 5-methyl-pentadecane, (n)-menthol, 3,7-dimethyl-(E)-2,6-octadienal, 3,7-dimethyl-2,6-octadienal, and nonadecane. Biochemical analysis showed that cisplatin intoxication was associated with significantly increased (p < 0.05) serum levels of urea and creatine and pro-inflammatory cytokines, as well as augmented renal tissue oxidative stress. Light microscopic examination showed loss of renal architecture, atrophied glomeruli, interstitial hemorrhage, dilated cortical tubules with cast formation, and excessive collagen production. Electron microscopic examination revealed compressed and karyorrhectic endothelial nuclei with chromatin condensation in the glomeruli, accumulation of mesangial matrix, and obliteration of glomerular blood capillaries. Co-administration of Citrus limonia oil attenuated these effects in renal histopathological, morphometric, and ultrastructural examinations, frequently in a dose-dependent manner. In conclusion, Citrus limonia oil can ameliorate the toxic effect of cisplatin on mice kidneys, probably through its antioxidant and anti-inflammatory effects.
Show more [+] Less [-]Effects of EDTA on adsorption of Cd(II) and Pb(II) by soil minerals in low-permeability layers: batch experiments and microscopic characterization Full text
2020
You, Xueji | Liu, Shuguang | Dai, Chaomeng | Zhong, Guihui | Duan, Yanping | Guo, Yiping | Makhinov, Aleksei Nikolavich | Júnior, José Tavares Araruna | Tu, Yaojen | Leong, Kah Hon
Ethylenediaminetetraacetic acid (EDTA) can serve as a washing agent in the remediation of low-permeability layers contaminated by heavy metals (HMs). Therefore, batch adsorption experiments, where pure quartz (SM1) and mineral mixtures (SM2) were used as typical soil minerals (SMs) in low-permeability layers, were implemented to explore the effects of different EDTA concentrations, pH, and exogenous chemicals on the HM-SM-EDTA adsorption system. As the EDTA concentration increased, it gradually cut down the maximum Cd adsorption capacities of SM1 and SM2 from approximately 135 to 55 mg/kg and 2660 to 1453 mg/kg; and the maximum Pb adsorption capacities of SM1 and SM2 were reduced from 660 to 306 mg/kg and 19,677 to 19,262 mg/kg, respectively. When the initial mole ratio (MR = moles of HM ions/sum of moles of HM ions and EDTA) was closer to 0.5, the effect of EDTA was more effective. Additionally, EDTA worked well at pH below 7.0 and 4.0 for Cd and Pb, respectively. Low-molecular-weight organic acids (LMWOAs) affected the system mainly by bridging, complexation, adsorption site competition, and reductive dissolution. Cu²⁺, Fe²⁺ ions could significantly increase the Cd and Pb adsorption onto SM2. Notably, there were characteristic changes in mineral particles, including attachment of EDTA and microparticles, agglomeration, connection, and smoother surfaces, making the specific surface area (SSA) decrease from 16.73 to 12.59 m²/g. All findings indicated that EDTA could effectively and economically reduce the HM adsorption capacity of SMs at the reasonable MR value, contact time, and pH; EDTA reduced the HM adsorption capacity of SMs not only by complexation with HM ions but also by decreasing SSA and blocking active sites. Hence, the acquired insight from the presented study can help to promote the remediation of contaminated low-permeability layers in groundwater.
Show more [+] Less [-]Source apportionment and seasonal variation in particulate PAHs levels at a coastal site in Belgium Full text
2020
Ravindra, Khaiwal | Dirtu, Alin C. | Mor, Suman | Wauters, Eric | Van Grieken, Rene
In the present study, estimation of the atmospheric polycyclic aromatic hydrocarbons (PAHs) was done in particulate samples collected from De Haan, Belgium, during different seasons. The sampling site was situated very close to the north sea and far from the influence of local or industrial activities. The levels of PAHs depicted a distinct seasonal trend, being highest during the spring season. The observations of the study indicated a mean value of 2.6 ng m⁻³ for concentration of all the 16 US EPA PAHs, thus being significantly lower when compared to results of previous studies focused on other sites. The dominating PAHs species reported were naphthalene, fluoranthene, benzo[a]anthracene, chrysene, and indeno[1,2,3c,d] pyrene. Assessment of the seasonal variation of the PAH levels was also done with respect to diagnostic ratio-based source identification, analysis of back trajectories, and principle component analysis. Burning of fossil fuels was observed to be the prominent source of atmospheric PAHs in the study area. Further, lifetime cancer risk assessment was performed to assess the detrimental health impacts on humans on being exposed to atmospheric PAHs. Particulate PAHs present in the ambient air of Belgium shows no carcinogenic health impacts. However, considering the industrial expansion in the region, efforts are required to prevent the environmental contamination of PAHs. Graphical abstract
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