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Experimental Aeration Investigations on Supersaturated Total Dissolved Gas Dissipation Texte intégral
2023
Yuanbo Yao, Huixia Yang, Yunyun Wang, Jiajia Liang and Ling Yang
Supersaturation of total dissolved gas (TDG) is mainly produced by high dam discharge, excess oxygen production by plant photosynthesis, and a sharp increase in water temperature, which may directly lead to fish and aquatic organisms suffering from “gas bubble disease” (GBD) or death. Aeration was one of the methods used to solve the dissipation of supersaturated TDG. In this paper, aeration had an obvious promotion effect on the dissipation of supersaturated TDG. For the calculation and analysis of supersaturated TDG dissipation coefficient, the aeration rate was proportional to TDG dissipation coefficient and had a promoting effect on it, while the aeration depth and aeration aperture were inversely proportional to TDG dissipation coefficient and played an inhibitory effect on it. The supersaturated TDG dissipation coefficient was affected by a factor of KTDG,Q> KTDG,D> KTDG,H. A quantitative relationship between the supersaturated TDG dissipation coefficient and aeration rate, aeration depth, and aeration aperture was obtained, respectively, as well as important expressions with comprehensive effect factors; their margins of error average within 10%. This research method has an important guiding significance for improving the living environment of fish and other aquatic organisms, alleviating the adverse effects of supersaturated TDG.
Afficher plus [+] Moins [-]Study on the Temporal and Spatial Distribution of Air Pollutants in Typical Cities of China Texte intégral
2023
He Tao and Tihao Hou
The present study selects cities such as Zhengzhou, Kaifeng, Anyang, Hebi, Xinxiang, Jiaozuo, and Puyang along the Yellow River Basin in Henan Province. The data of six pollutants, such as PM2.5, PM10, SO2, CO, NO2, and O3, in various cities from 2019 to 2021, and the monthly primary pollutant data of seven cities in the past five years were collected through various channels. The air quality of the above seven cities was analyzed with the spatial-temporal distribution of pollutants as the research objective and geographic information system as the research tool. The results show that affected by the distribution of key pollution sources and meteorological conditions in the urban area, the PM2.5 concentration generally shows a zonal feature of decreasing from northwest to Southeast. The high-value area is located in the north and west of the integrated area of the seven cities, and the low-value area is located in the Southeast of the seven cities.
Afficher plus [+] Moins [-]Measurement of Black Carbon Absorption Coefficients Using an Aethalometer and Their Association with Visibility Texte intégral
2023
Khadeejeh M. Hamasha
Black carbon (BC) is a pollutant aerosol affecting climate and human health. Light absorption coefficients of black carbon (Babs) were measured using an aethalometer model AE33 at wavelengths 370, 470,520,660,880, and 950 nm. Babs for the seven wavelengths at seven sites in Jordan fluctuated with time and peaked at rush hours. The daily average values for all sites were inversely proportional to the wavelength. The average daily visibility values in the seven Jordan sites varied between 72 km and 211km. In the Irbid site, the daily average visibility values for 7-13 Nov. 2021 varied between 43 km and 107 km. BC varied from hour to hour and from day to day. The daily average values of BC in Irbid for the period of 7 -13 Nov. 2021 varied between 2.24 μg.m-3 and 4.66 μg.m-3. BC peaked at the rush hour and had the lowest values on Friday. About 90% of the measured BC was from fossil fuel sources and 10% from biomass-burning sources.
Afficher plus [+] Moins [-]Denaturing Gradient Gel Electrophoresis (DGGE) Analysis Indicating Increased Microbial Diversity in Landfill Area Near Conserved Wetland Texte intégral
2023
M. B. Chakraborty, S. R. Patgiri, A. S. Rahman, A. Dasgupta and G. Pegu
The ecological balance of an ecosystem has a relation to its biodiversity. Although it has been established that biodiversity and ecological stability are related, generalization about the exact nature of this relation remains elusive and more so in microbial diversity. A growing volume of studies has indicated that anthropogenic activities impact biodiversity, but it is difficult to generalize the impact of anthropogenic activities on microbial diversity. Landfilling by municipal solid waste is one such activity where microbes play a major role, and leachates are released from the landfill, altering the soil’s physical and chemical nature. Change in factors like carbon source, pH, and toxicity of the soil is most likely to affect the indigenous microflora of the soil. The present study was undertaken to compare the microbial diversity of soil receiving landfill leachate with that of the soil not receiving any landfill leachate to assess the impact of the landfilling activity on microbial diversity. The landfill site selected for the study was that of Kamrup Metro District of Assam, located at Boragaon, near the Ramsar wetland called Deeporbeel. By using the Denaturing Gradient Gel Electrophoresis (DGGE) method, it has been found that the microbial diversity of the soil receiving leachate was higher than that of the soil not receiving any leachate from the landfill.
Afficher plus [+] Moins [-]Stabilisation of Spent Wash by Polyhydroxybutyrate (PHB) Producing Microorganisms Isolated from Karad Region, Maharashtra Texte intégral
2023
G. V. Patil and G. R. Pathade
In recent years, there has been a significant increase in the needs of the overgrowing population. Naturally, industrial belts increased worldwide to satisfy the variety and quantity of needs. While producing the products, a huge quantity of waste is generated and added continuously to the environment, causing hazardous effects on the flora and fauna. Spent wash is one of the most important types of industrial waste since it is the liquid waste that is left over after making alcohol and it pollutes the environment. Despite effluent quality standards, untreated or partially treated sewage frequently enters water courses or soils. It is always overloaded with organic and inorganic substances. The stabilization of the effluent by microorganisms is reflected in the form of COD reduction. The present study attempted to isolate the PHB-producing organisms and use them to stabilize the spent wash. The locally isolated, characterized, and identified 11 PHB-producing microorganisms from the Karad region of Maharashtra were used to stabilize spent wash. They include Candida orthopsilosis, Bacillus subtilis, Bacillus cereus, Bacillus megaterium, Klebsiella grimontii, Citrobacter fruendii, and members of Staphylococcus and Rhodococcus. All potential organisms were reported to stabilize the spent wash. The degree of stabilization was measured in terms of the percent reduction of COD and BOD. The % reduction was reported at 95.31% and 81.39% of COD and BOD, respectively, by Klebsiella grimontii, followed by 92.18% and 80.46% reductions of COD and BOD, respectively, by Staphylococcus. These organisms are promising in the treatment of spent wash.
Afficher plus [+] Moins [-]Comparative Advanced Oxidation Decolorization of the Triphenylmethane Dye with Dimethyl Dioxirane and Hydrogen Peroxide Texte intégral
2023
S. Vinotha and A. Leema Rose
Methyl Violet (MV), a triphenylmethane dye, has been subjected to comparative studies with hydrogen peroxide and dimethyl dioxirane under optimum situations. When employing hydrogen peroxide, the photolysis process becomes slower, but the dye solutions are entirely decolored and mineralized. The decolorization rate exhibits pseudo-first-order kinetics. The effect of pH, oxidant dosage, and methyl violet concentration on the degradation is also examined. Generated o-leucoaniline,1,3-diphenylurea,2-hydroxy benzoic acid, phenol, acetone, water, carbon dioxide, and carbon monoxide are identified and measured by GC-MS analysis. These substances remain in the dye solution along with dimethyl dioxirane, which is released faster during the last stages of degradation. The degradation rates of methyl violet reached 97.9% and 65.8% within 30 mins and 180 min of reaction time using dimethyl dioxirane and hydrogen peroxide.
Afficher plus [+] Moins [-]The Impact of Climate Change, Economic Growth, and Population Growth on Food Security in Central Java Indonesia Texte intégral
2023
Suryanto Suryanto, Irwan Trinugroho, Fitri Susilowati, Jean Baptiste Aboyitungiye, and Yuaninda Hapsari
As climate change continues to cause more frequent weather shocks such as droughts and floods and increasingly erratic rainfall, people in developing regions are threatened by crop failures and hunger. In this study, the researchers describe how climate change influences food security in Central Java, seen from the frequency of floods, rainfall, and rainy days. This study also added another variable, i.e., economic growth, reviewed through GRDP and the amount of rice production. Using the Common effect model, the study results revealed that rainy days and population were the variables significantly influencing food security in cities/regencies in Central Java Province. Meanwhile, two other variables, i.e., rainfall and GRDP, had no significant effect on food security in cities/regencies in Central Java Province.
Afficher plus [+] Moins [-]Effects of Traffic on Particulate Matter (PM2.5) in Different Built Environments Texte intégral
2023
Naina Gupta and Sewa Ram
Globally, vehicular pollution is one of the greatest concerns in urban areas. Several studies on air pollution have been conducted using deterministic, statistical, and soft computing methods. However, there has been little research on how soft-computing methods like Artificial Neural Networks (ANN) can help us comprehend vehicular pollution’s non-linear and highly complex dispersion. This study uses an ANN-based vehicular pollution model to investigate the effect of vehicular traffic on PM2.5 concentrations in built-up and open terrain-surrounding environments. Five distinct pollution models were developed for two locations in Delhi, considering PM2.5 pollutants, meteorological variables, traffic flow, and traffic composition into account. The results concluded that under open terrain conditions, the significance of the traffic variable in its association with PM2.5 is almost half the significance observed under built-up conditions. Also, in terms of PM2.5 reductions, the maximum reduction observed at Location-1 (built-up environment), and Location-2 (open terrain environment) is 1.85 and 2.44 times the percent reduction in traffic during peak hours, respectively. The study’s findings have significant ramifications for the current practices of ignoring the contribution of traffic and the built environment to pollution and adopting measures like an odd-even rule and high fuel and parking prices to combat pollution.
Afficher plus [+] Moins [-]Comparative Study on the Indoor Air Quality in Critical Areas of Hospitals in Malaysia Texte intégral
2023
Kerk Teck Seng, Lee Chia Shen, Ngo Sin Ling, Sim Pei Chin, Tan Jia Xin, Tan Kai En, Adnaan Ahmed Jama, Azian Hariri and Nurul Fitriah Nasir
Indoor Air Quality (IAQ) is the air quality within and around buildings and structures, particularly regarding building occupants’ health and comfort. IAQ assessments were performed using an objective measurement of molecular gaseous pollutants to determine the IAQ profile in the hospital’s critical areas. It also analyses the effects on patients in different environments and the sources that result in deviations from approved criteria. This comparative study is aimed to investigate the concentration of different compounds in different critical departments in the hospital and propose solutions to the related problem as an improvement in indoor air quality. The data was compared with the standards and regulations. It was found that the TVOC level in the CCU department, specifically in the fluoroscopy room, has exceeded the allowable limit. A few suggestions have been raised to lower the exceeded value. The risks and symptoms held by the occupants in the hospital buildings if they face poor indoor air quality were discussed. Further study can be conducted to relate the short and long-term health issues among medical staff to poor indoor air quality.
Afficher plus [+] Moins [-]Analysis of Shoreline Change of North Central Timor Regency, Indonesia Texte intégral
2023
L. Ledheng and E. M. Y. Hano’e
Shoreline change is a process that occurs due to the impact of natural factors and human activities. Geographically, the coastal area of North Central Timor Regency (NCT) is in the northern part of the island of Timor, East Nusa Tenggara Province (ENT). Physically, the area is affected by the oceanographic dynamics of the Sawu Sea waters and aquaculture activities, which impact the damage to coastal ecosystems. This study aims to analyze shoreline change in the northern coastal area of NCT Regency. The data used are Landsat 8 images from 2015-20221 to describe current conditions. Meanwhile, Landsat 5 imagery data from 1990 - 2000 was used to describe the initial conditions. The satellite imagery is analyzed to map shoreline changes that experience accretion or abrasion. The results show that the shoreline of the study area has experienced changes in accretion and abrasion. Based on the area of change in the northern coastal area of NCT Regency, the dominant accretion area was 1108.07 m2 with a rate of change of 20.19 m.year-1, as long as 1021 meters, while the abrasion was 845.43 m2 at a rate of 12.65 m.year-1 as long as 36520 meters. The average shoreline change distance in accretion conditions was 11.3 meters, while the abrasion was 7.93 meters. The shoreline shift due to the highest abrasion in Ponu was -16.08, while accretion in North Oepuah was 35.63 meters. The results of this research will contribute to planning the management of the coastal area of NCT Regency.
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