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Comparative evaluation of ultrafiltration and dynamic membranes in an aerobic membrane bioreactor for municipal wastewater treatment
2019
Isik, Onur | Abdelrahman, Amr Mustafa | Ozgun, Hale | Ersahin, Mustafa Evren | Demir, Ibrahim | Koyuncu, Ismail
This study investigated the applicability of self-forming hollow fiber dynamic membrane (DM) as a low-cost alternative to ultrafiltration (UF) membrane. A hollow fiber polyester fabric was used as a support material to form the DM layer. Submerged DM and UF hollow fiber membrane were placed in the same reactor in order to compare the treatment and filtration performance of each membrane. Morphological analyses were also carried out for DM surface. The system was operated continuously at a flux of 5 L/m² h for 85 days. High COD removal efficiency and total suspended solids (TSS) rejection were achieved by the DM. Transmembrane pressure (TMP) of the DM was higher in comparison to the UF membrane, which was related with the formation of cake layer in DM. DM technology can be used as an alternative to UF membrane for municipal wastewater treatment.
Show more [+] Less [-]Effects of mutual grafting on cadmium accumulation characteristics of first post-generations of Bidens pilosa L. and Galinsoga parviflora Cav
2019
Li, Hongyan | Wang, Jin | Lin, Lijin | Liao, Ming’an | Lv, Xiulan | Tang, Yi | Wang, Xun | Xia, Hui | Liang, Dong | Ren, Wei | Jiang, Wei
We studied the effects of mutual grafting on cadmium (Cd) accumulation characteristics on the first post-generations of the Cd-hyperaccumulator plants Bidens pilosa L. and Galinsoga parviflora Cav. The seeds from scions and rootstocks of B. pilosa and G. parviflora were collected and planted in Cd-contaminated soil in pot and field experiments. In the pot experiment, rootstock treatment increased the shoot biomass of B. pilosa post-grafting generations, compared with ungrafted B. pilosa, but decreased the Cd content in shoots and Cd extraction by shoots of post-grafting generations; scion treatment decreased or had no significant effect. Mutual grafting resulted in no significant differences to the photosynthetic pigment contents in B. pilosa post-grafting generations. Compared with ungrafted G. parviflora, scion treatment increased the shoot biomass, photosynthetic pigment content, and Cd extraction by shoots of G. parviflora post-grafting generations, but rootstock treatment did not lead to significant differences. Mutual grafting resulted in no significant differences to the Cd contents in shoots of G. parviflora post-grafting generations. In the field experiment, only rootstock treatment increased the shoot biomass of B. pilosa post-grafting generations, and only scion treatment increased the shoot biomass and the Cd extraction by shoots of G. parviflora post-grafting generations. Therefore, mutual grafting of scions may enhance the phytoremediation ability of G. parviflora first post-grafting generations.
Show more [+] Less [-]Environmental improvement in the printing industry: the case study of self-adhesive labels
2019
Medeiros, Diego Lima | Braghirolli, Felipe Luiz | Ramlow, Heloisa | Ferri, Gabriela Neves | Kiperstok, Asher
Labels are used for marketing, technical information, local of production and environmental declarations of products. The aim of the study was to evaluate the life cycle of two sets of front and back adhesive labels made with different liners: polyethylene terephthalate (PET) and glassine paper. The study is a pioneering initiative in the labelling industry using life cycle assessment, especially in Brazil. The attributional life cycle assessment method was based on the ISO 14044 standard and covered the entire life cycle, cradle to grave. Primary data for key suppliers, printing facility and label use composed the foreground data, while the ecoinvent database composed the background data. The material efficiency was assessed through mass balance. The impact assessment methods were cumulative energy demand for non-renewable energy and ILCD 2011 midpoint for the environmental categories. The glassine liner is heavier than the PET which resulted in larger environmental indicator values for production, transportation and waste treatment. On the other hand, energy demand of label set with glassine liner was lower than the PET. Furthermore, the hotspot analysis of each impact category was presented per process and substance. The label set made with glassine liner tended to present larger environmental indicator values in most categories, 13 of the 16 assessed, compared to the label set made with PET liner, despite the uncertainties. Contribution analysis identified that the pre-manufacturing step presented larger environmental indicator values than manufacturing, use and post-use steps along the label set life cycle. Therefore, environmental improvement opportunities were evaluated through scenarios of end of life, recycled inputs, domestic suppliers, waste prevention and product redesign. Moreover, the life cycle assessment was useful for diagnosing the energy and environmental profiles of self-adhesive labels and planning cleaner production measures that avoid environmental tradeoffs.
Show more [+] Less [-]Recycling of crushed waste rock as backfilling material in coal mine: effects of particle size on compaction behaviours
2019
Li, Meng | Zhang, Jixiong | Song, Weijian | Germain, Deon M.
Crushed waste rocks can be used as materials for backfilling goafs, so as to achieve the simultaneous goals of processing solid waste and controlling surface subsidence; however, particle size distribution directly affects the compaction of crushed waste rocks. Therefore, by employing a self-designed bidirectional loading test system for granular materials, this study tested compaction characteristics of crushed waste rocks with four different particle size distributions. Moreover, this research tested the changes of parameters in lateral and axial loading of crushed waste rocks and analysed the influence of particle size distribution on lateral strain, axial strain, porosity, lateral stress, and lateral pressure coefficient during compaction. The test results show that (1) particle size distribution affects porosity, strain, and lateral pressure coefficient of crushed waste rocks under lateral and axial loading. (2) For the samples under particle size distribution ranging from 0 to 10 mm, the initial porosity is low and deformations are small under axial loading, so that particles can make contact and bear effective stress in grain-grain contact. Therefore, more stress is transferred to the lateral direction. (3) After compaction, the curves of the samples of crushed waste rocks under four particle size distributions all shift upwards in comparison with those before compaction, indicating that particles are crushed and the proportion of small particles constantly increases. (4) A reasonable particle size distribution can significantly improve stress characteristics, reduce crushing of particles in the samples, and increase the stiffness of the samples, so as to achieve better compaction effects.
Show more [+] Less [-]Biomonitoring chronic lead exposure among battery manufacturing workers in Tunisia
2019
Nouioui, Mohamed Anouar | Araoud, Manel | Milliand, Marie-Laure | Bessueille-Barbier, Frédérique | Amira, Dorra | Ayouni-Derouiche, Linda | Hedhili, Abderrazek
The aim of the study was the biomonitoring of the chronic exposure to Pb by measuring its levels in blood, urine, and hair of battery workers. Blood lead (BPb), urinary lead (UPb), hair lead (HPb), and urinary δ-aminolevulinic acid (UALA) levels were determined for 52 workers in a battery plant and compared to those of 20 non-occupational exposed subjects (controls). BPb and UPb levels were determined by graphite furnace atomic absorption spectrometry (GFAAS). HPb levels were measured by triple quadrupole ICP-MS and UALA levels were determined using cation exchanger column. The measured levels were significantly higher compared to the controls exceeding the OSHA cutoff values (p < 0.01). The GM mean levels of BPb, UPb, UALA, and HPb of workers were 715 μg L⁻¹, 331 μg L⁻¹, 16.3 mg g⁻¹, and 234 μg g⁻¹, respectively. The GM mean levels of BPb, UPb, UALA, and HPb of controls were 93.6 μg L⁻¹, 36.3 μg L⁻¹, 1.9 mg g⁻¹, and 1.8 μg g⁻¹, respectively. Significant correlations were observed between BPb and UALA (r = 0.630, p = 0.000), UPb and UALA (r = 0.566, p = 0.000), and between BPb and HPb (r = 0.466, p = 0.004). The significant correlation between BPb and HPb suggests the usefulness of hair for assessing occupational exposure particularly when the study area presents medium to high levels of Pb pollution. The association between Pb biomarkers and potential confounding factors revealed significant influence of the occupational factor over smoking and alcohol consumption. The results of this study urge for the reinforcement of the implemented engineering controls and safety measures in order to reduce exposure and to address the health issues related to Pb poisoning.
Show more [+] Less [-]Enhancement in combustion, performance, and emission characteristics of a diesel engine fueled with diesel, biodiesel, and its blends by using nanoadditive
2019
Vellaiyan, Suresh
This article presents the results of investigations carried out to evaluate the improvement in combustion, performance, and emission characteristics of a diesel engine fueled with neat petro-diesel (PD), soybean biodiesel (SB), and 50% SB blended PD (PD50SB) by using carbon nanotube (CNT) as an additive. The acid–alkaline-based transesterification process with sodium hydroxide (NaOH) as a catalyst was applied to derive the methyl ester of SB. A mass fraction of 100 ppm CNT nanoparticle was blended with base fuels by using an ultrasonicator and the physiochemical properties were measured based on EN standards. The measured physiochemical properties are in good agreement with standard limits. The experimental evaluations were carried out under varying brake mean effective pressure (BMEP) conditions in a single-cylinder, four-stroke, and natural aspirated research diesel engine at a constant speed of 1500 rpm. The results reveal that the SB and its blend promote shorter ignition delay period (IDP) that is resulting in lower in-cylinder pressure (ICP) and net heat release rate (NHR) compared to PD. The SB and its blend increase the brake specific fuel consumption (BSFC), and reduce the brake specific energy consumption (BSEC) and exhaust gas temperature (EGT), due to lower heating value, and efficient combustion, respectively. As far as the emission characteristics are concerned, the SB and its blend promote lower magnitude of hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO₂), and smoke emissions compared to PD except for oxides of nitrogen (NOₓ) emission. The CNT nanoparticle inclusion with base fuels significantly improves the combustion, performance, and emissions level irrespective of engine load conditions.
Show more [+] Less [-]Contamination status and potential release of trace metals in a mangrove forest sediment in Ho Chi Minh City, Vietnam
2019
Dung, Tran Thi Thu | Linh, Tong My | Chau, Tran Bích | Hoàng, Trường Minh | Swennen, Rudy | Cappuyns, Valerie
Can Gio district is located in the coastal area of Ho Chi Minh City, southern Vietnam. Discharge of wastewater from Ho Chi Minh City and neighboring provinces to the rivers of Can Gio has led to concerns about the accumulation of trace metals (As, Cu, Cr, Ni, Pb, and Zn) in the coastal sediments. The main objective of this study was to assess the distribution of As, Cu, Cr, Ni, Pb, and Zn in surface and core sediments and to evaluate the contamination status in relation to local background values, as well as the potential release of these selected trace metals from sediments to the water environment. Sediment characteristization, including determination of fine fraction, pH, organic matter, and major elements (Al, Fe, Ca, K, Mg, and S), was carried out to investigate which parameters affect the trace metal enrichment. Fine fraction and Al contents were found to be the controlling proxies affecting the distribution of trace metals while other sediment characteristics did not show any clear influence on trace metals’ distribution. Although As concentrations in the sediments were much higher compared to its reference value in other areas, the enrichment factor based on local background values suggests minor contamination of this element as well as for Cr, Cu, and Pb. Risk assessment suggested a medium to very high risk of Mn, Zn, and Ni under acidification. Of importance is also that trace metals in sediments were not easily mobilized by organic complexation based on their low extractabilities by ammonium-EDTA extraction.
Show more [+] Less [-]A novel sorbent for removal of reactive textile dye: TDPA-KCl
2019
Tosun Satır, Ilknur | Sayin, Fatih | Gedikbey, Tevfik | Tunali Akar, Sibel
The use of alunite as an adsorbent for the removal of dye was the aim of this report. Mixing the alunite with different salts may allow adsorption with higher efficiency. In the present study, the thermal decomposition product of alunite-potassium chloride mixture (TDPA-KCl) was used efficiently and inexpensively to remove Reactive Blue 49 (RB49) dye. The adsorption capacity of TDPA-KCl was found to be affected by pH, temperature, adsorbent amount, calcination temperature, dye concentration, and ionic strength. The highest RB49 adsorption yield was obtained at an initial pH of 2 and an equilibrium was reached within 20 min using 80 mg of adsorbent. The most suitable kinetic model was found as the pseudo-second-order and compatible isotherm was determined as the Langmuir model. The optimum adsorption capacity was found as 119.10 mg g⁻¹ at 40 °C. ∆G°, ∆H°, and ∆S° values were calculated. A positive value of ∆H° stated that the adsorption is exothermic and spontaneous. In addition, ∆G° showed a more negative value when temperature was increased. Column studies indicated that TDPA-KCl could be effectively used for five cycles without any loss in its desorption potential. Breakthrough studies also supported a favorable adsorption of RB49 onto TDPA-KCl. This study showed that TDPA-KCl is a practical, efficient, and inexpensive adsorbent to remove reactive dyes from wastewater.
Show more [+] Less [-]Cooking fuel decision-making and family structure: a field study in China
2019
Hou, Bingdong | Liao, Hua | Wang, Jin-Wei | Wang, Fangzhi | Zhang, Hongliang
Household air pollution caused by solid fuel use for cooking is prevalent in rural China and generates various environmental and health problems. Various potential impact factors on cooking fuel decision such as income, education, modern energy, and infrastructure are examined. However, the role of family structures has been ignored. A survey on household energy consumption pattern interrelating socio-economic and demographic factors was conducted in ten villages in Northern China using stratified random sampling technique. The number of family member eating together influences households’ cooking fuel decision-making significantly. The numbers of school-age children and family members under 6 and above 60 years old have no significant influence on the household’s cooking fuel decision-making respectively. Compared with families with neither child nor the elderly, those with no child but at least an elderly member have 0.103 lower probability of choosing clean fuels as their primary cooking fuel. Hence, the elderly owns a heavyweight in the household fuel decision-making process in rural China, and the government should formulate policies more in line with the background of the times to deal with rural energy issues.
Show more [+] Less [-]Phthalate exposure and cumulative risk in a Chinese newborn population
2019
Li, Xueyan | Liu, Liangpo | Wang, Heng | Zhang, Xueqin | Xiao, Tonghu | Shen, Heqing
Phthalates have been attracted as a considerable attention in toxicological research as well as public health context due to their ubiquitous occurrence and potential adverse health effects. Newborns are susceptible to the environmental risk factors; however, data are still limited on newborn phthalate exposure and risk assessment worldwide, especially in China. This study was nested in a cross-sectional retrospective study of 1359 pregnant women recruited in Xiamen Maternity and Child Care Hospital, China, during June to July 2012. All urine samples from newborn were collected using disposal diapers during the first two postnatal days, and seven phthalate metabolites were measured by LC-ESI-MS/MS. Phthalate exposure and accumulation risk were evaluated based on the measured newborn urinary internal doses. The detection rate (96.5%) and the median concentration (17.5 ng/mL) of mono-n-butyl phthalate (MBP) were the highest, while monobenzyl phthalate (MBzP) concentration was the lowest with a detection rate (1.50%). By estimating the daily intakes of the parent phthalates, their EDI were 0.04, 0.10, 0.32, 0.00, and 0.12 μg/kg-bw/day for dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalates (DBP), benzyl butyl phthalate (BBzP), and di-(2-ethylhexyl) phthalate (DEHP), respectively. The newborns were commonly exposed to phthalates but no one exceeds the regulated tolerable daily intake (TDI) values in this large newborn population.
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