Science and Technology Development Journal: Science of the Earth & Environment
The jornal of Viet Nam National University Ho Chi Minh City
Color removal efficiency of rice husk biochar modified with magnetized iron oxides and nano zero valent iron for decolorization of dyeing wastewater
Rice husk biochar, a rich-carbon material, can be modified with other reactive elements to improve its original properties for organic-contaminant removal efficiency. In this study, rice husk was heated to 600 oC without air in a closed-furnace for producing the rice husk biochar (BC600). BC600 was then magnetized for making an intermediate magnetized rice husk biochar (BC600- mag). Finally, nano zero valent iron (nZVI) was synthesized on BC600-mag for producing magnetized biochar impregnated nZVI (BC600-mag-nZVI). Batch experiments were conducted to investigate color removal efficiency of BC600-mag-nZVI for the reactive dyes yellow (RY145), red (RR195) and blue (RB19) from dyeing solutions with the initial color concentrations of approximately 400 Pt-Co. Results showed that, for RY145 and RR195, the optimum color removal efficiency (nopt ) achieved the values of 95 and 93% at doses of 0.50 and 1.50 kg BC600-mag-nZVI/m3 dyeing solution, according to the treated color decreased to 21 and 30 Pt-Co, respectively, which are lower than the allowable discharged standard of column A (≤ 50 Pt-Co) of QCVN 40:2011/BTNMT, while for RB19, the nopt achieved the values of 63 % at dose of 8.00 kg BC600-mag-nZVI/m3 dyeing solution, according to the treated color decreased to 147 Pt-Co which is lower than the allowable discharged standard of column B (≤ 150 Pt-Co) of QCVN 40:2011/BTNMT. In addition, with increasing dose of the modified biochars, the color removal efficiency increased accordingly, achieving almost 100% for RY145 and RR195 and over 70% for RB19. It is concluded that the magnetic-nZVI rice husk biochars effectively removed the reactive dyes. In the other hand, the impregnation of nZVI particles on the biochar backbone spatially separates the particles, prevents their aggregation and therefore enhances their reactivity This study therefore proposes a new application of rice husk biochar modified with magnetized iron oxides and zero valent iron decolorization of dyeing wastewater
Copyright (c) 2020 Science and Technology Development Journal: Science of the Earth & Environment
Research application coal material is prepared from maccadamia peel and denatured by H2O2 to treat methylene blue
Macadamia shell contains a carbon content (47 - 49%), in addition, the shell contains 46.52% Oxidation, Hidro 6.10%, Nitrogen 0.36% and relatively low ash content of only 0.22%, this indicates the grain Macadamia has the potential to become activated carbon thanks to the above characteristics. This study was conducted to modify activated carbon by oxidizing agents to change the surface structure of activated carbon from hydrophobic to hydrophilic, non-polarizing to polarization, increasing the amount of adsorption simultaneously creating more durable links between dyes and activated carbon. Study of Methylene Blue wastewater treatment with coal from Maccadamia shell modified with H2O2 agent at H2O2 ratio : coal = 10:1. Research results show that Methylene Blue adsorption capacity reaches 1g /266.26mg Methylene Blue at optimal conditions corresponding to 25% concentration and 48 hours of soaking time. Analysis of infrared spectra showed that coal is modified by H2O2 agent with functional groups –OH, Carboxylic functional group C=O, group C-H in NH3, C–N group in Amine aliphatic or in Alcohol or Phenol and C–O bonding. Modified coal by H2O2 oxidation agent has Methylene Blue color treatment efficiency of 93.26%, corresponding to the original color of 474.67 Pt - Co at the respective optimal conditions pH = 8.5, dose of 1 g/L and treatment time of 60 minutes. Research results are similar to other research results and are applicable to color wastewater treatmentMoreover, experimental results based on the results of the 6 simulations for simulation error, the track error in the CIMSS test decreased 14% and 14.3% respectively in the 48-hour forecast period and 72 hours compared with the MPH test, and decreased 14% and 23.9% respectively compared to the global GFS forecast. For storm intensity (Pmin and Vmax), the CIMSS test also resulted in significantly improved errors in the 72-hour forecast period compared to MPH testing. These results confirmed that the assimilation of the satellite wind data into the input field of the model has a positive effect on Haiyan storm intensity and trajectory prediction skills. We may used this research to applying the multi-physics ensemble Kalman filter for forecasting storms affecting Vietnam.
Testing of the Multi-Physics Ensemble Kalman filter to Simulate the Track and Intensity of the Typhoon HaiYan (2013)
This paper presents some experimental results of the multi-physics ensemble Kalman filter method which assimilating the satellite wind data in WRF model to simulate the track and intensity of the typhoon HaiYan (2013). The study conducted two experiments.: (1) Ensemble forecast with multiphysics ensemble Kalman filter assimilates the satellite wind data (CIMSS); (2) multi-physics Ensemble forecast (MPH). The results of atmospheric circulation analysis in the simulation started at 12 UTC (international time) until November 7, 2013, showing that the trend and intensity of the general circulation in the CIMSS test are similar to the real development. So the results of the storm trajectory forecast of CIMSS test at the 48-hour forecast limit onwards are better than the MPH test. Moreover, experimental results based on the results of the 6 simulations for simulation error, the track error in the CIMSS test decreased 14% and 14.3% respectively in the 48-hour forecast period and 72 hours compared with the MPH test, and decreased 14% and 23.9% respectively compared to the global GFS forecast. For storm intensity (Pmin and Vmax), the CIMSS test also resulted in significantly improved errors in the 72-hour forecast period compared to MPH testing. These results confirmed that the assimilation of the satellite wind data into the input field of the model has a positive effect on Haiyan storm intensity and trajectory prediction skills. We may used this research to applying the multi-physics ensemble Kalman filter for forecasting storms affecting Vietnam.
Propose a model integrated farming production towards zero emissions for livestock households: typical application for cattle breeding households in Seven Mountain areas
The study has proposed an integrated zero-emission farming model based on livestock production. The model applies ecological solutions, revolving solutions, and closures of energy flows along with utilizing the local environmental conditions available to help maintain livelihoods for the people. Typical models for Mr. Nguyen Van Hai households in Trung An hamlet, Le Tri commune, Tri Ton district, An Giang province. The results show that 3.18 m3 /day of livestock and domestic waste water is treated and reused for agriculture, 39,065.31 tons of CO2tđ/year is collected in the form of biogas for cooking, models help to maintain existing livelihoods, creating a number of new livelihoods to increase income of VND 64,400,000/year, ensuring environmental protection requirements, reducing existing livelihood dependence on external actors such as price, food, human resources, etc. This can be considered as the best model for cow farmers; can overcome the disadvantages of previous local livelihood models; Both in terms of long-term applicability, as well as the development of a large number of households, there is an increase in the ability to connect among households in order to create mutual support in the case of a residential area with the same main livelihood as livestock cow.
Development of agro-industrial eco-model (aicem) for production of raw coconut jelly sector in Mekong Delta
The argo-industrial model producing of closed ecosystem in Mekong Delta is a development in the world. In this paper, the construction method outlined criteria identifys for the agro-industrial production model toward dual-closed ecological direction for coconut jelly processing facility. Set up criteria determines the impacts of production technology, the efficiency of using energy and natural resources, sustainable livelihoods, and the replicability of the model that will affect on the sustainability of the model. The research methodology was based on the results of surveys, investigation, and assessment of current model, and identifying a scientific basis for the set up criteria. Based on that, set up criteria was propose and application for a coconut jelly processing facility for Nguyen Thanh Trung household in Nhon Thanh commnune, Ben Tre city, Ben Tre province and recommend the solution for completed model based on eco-technique and closed matter & energy line. The results of the model meet all the requirements of the set up criteria. The quality of water supply meets the standards for coconut jelly processing. Treated wastewater by aquatic plants system meets the standard for wastewater discharges into the water resource. Water comsumption was saved and reduced the greenhouse gas emissions from burning wood for coconut jelly processing. The production costs were saved, resulting increasing income for household. This is pilot the perfected model to expand to other facilities
Study on using modified laterite in the heterogeneous Fenton process for removing dye compound
In this work, laterite was modified by iron (III) sulfate (Lat-Fe), and it was used in heterogeneous Fenton for the removal of Reactive Yellow 160 dye (RY 160). Properties of chemical composition, surface morphology and specific surface area of modified laterite were characterized by Energy dispersive X-ray spectroscopy (EDX), scanning electron microscopes (SEM) and BET method and that laterite was assessed effectively to apply in the heterogeneous Fenton process. Experimental investigations about conditions such as pH, H2O2 oncentration, and modified materials were conducted to look for the suitable conditions for removing dye compound by Fenton process. Studied results showed that modified laterite by procedure without iron Fe3+ had not catalyzed activation in Fenton process. However, using modified laterite by iron (III) sulfate (Lat-Fe) get good results in the heterogeneous Fenton process for removing Reactive Yellow 160 dye. Removing Reactive Yellow 160 dye (RY 160) with initial concentration of 50ppm with investigated optimal conditions of Lat-Fe: 1,25g/L, H2O2 2,45 mM, pH 7 at 30oC get 70% of removal efficiency in 120 minutes.
Application of CANON-SBR process for ammonium removal from old municipal old landfill leachate
CANON (Completely Autotrophic Nitrogen-removal Over Nitrite) is the process combined Partial Nitritation and Anammox in a single reactor to remove ammonium from wastewater. This study used a lab-scale SBR Sequencing Bach Reactor for CANON process (CANON-SBR) to treat ammonium from old municipal solid waste landfill leachate. The reactor was run at two phases: (i) In adaptation phase, the synthetic wastewater containing 139 ± 9 mg/l as NH4+-N was fed into the reactor, and (ii) In operation phase, the reactor was fed with leachate taken from the Go Cat municipal lanfill which was closed since 2007. The reactor was run at ammonium loading rate of 0.2 kgN/m3.day and HRT of 0.6 day in the adaptation phase. pH and DO values in the reactor were controled in the ranges of 7.4 – 7.6 and 0.1 – 0.2 mg/l, respectively. After 15 days of adaptation, total nitrogen removal of 72% was obtained. Then, the leachate containing 3,000 mg/l NH4+-N and 100 mg/l TSS was fed into the SBR. DO and pH were the key operation parameters for CANON process control. CANON-SBR obtained stable treatment efficiciency at DO ranging from 0.05-0.2 mg/l and pH values of 7.5 – 7.6. The obtained TN and COD removals were above 93% and 40%, respectively, when SBR was run at nitrogen loading rate of 0,4 kgN/m3.day and HRT of 7.43 day. TN concentration of the final batch was 34 mg/l that is met with column B1 QCVN 25:2009/BTNMT (TN< 60 mg/l), while nitrite and nitrate were not detected in the supernatant. This shows that co-existence of denitrifiers which consume nitrate produced from Anammox was available in biomass of the reactor. Numerous Anammox granules in dark red color happened after 20 days of running with leachate. Size of Anammox granules ranged from 5 - 800 μm, among that 73% of granule with size of 20 - 200 μm. The average granule diameter was 97.57 μm
Chronic efffects of bisphenol an exposure on zebrafish (Danio rerio) at juvenile state
Bisphenol A (BPA) is an endocrine disrupting chemical, therefore some countries have banned the use of it in plastic containers for food storage and plastic toys for children. BPA can be found in natural waters with measured concentrations varying from ng/l to mg/l. However, in fact that the chronic ecotoxicology data obtained from aquatic animals for BPA exposure at these levels are quite few. Methods: In this study zebrafish at 30 days of age were exposed to four variants 0, 1, 10 and 100 μg/l BPA along 60 days, which is the fasted growth period in zebrafish (Juvenile stage). At the end of the experiments, all fish weight and length were measured and their fresh livers were used for histological assessment. Results: The results showed that weight and length of fish in 100 mg/l BPA group increased significantly as compared with that in the other experimental groups. Also only in this group, changes in hepatic morphology such as vacuolar number and size increasement, cytoplasmicand/or nuclear enlargement, glycogen reduction, lipid enhancement, were observed, but especially no significant inflammation. Fish in the other groups exposed to BPA concentrations <100mg/l had no change in all targeted endpoints as compared with that of the control. Conclusion: Chronic exposure of 100mg/L BPA to zebrafish along the fast-growth period (Juvenile) caused increasement of weight and length, and altered morphology of hepatic cells, that may harm to liver functions
3D numerical modeling of flow and sediment transport in rivers and open channels
Numerical model is a useful tool in studying the flow and sediment transport, change in river bed and is built on solving governing differential equations. Numerical model has many different levels and three-dimensional model is the highest level, allowing detailed simulation of flow and sediment transport process in 3D space. The paper presents a method calculating three - dimensional flow and sediment transport in the open channel. Water level and flow velocity are solved from three-dimensional equations with hydrostatic hypothesis. Concentration of suspended sediment, bottom sediment and bottom evolution is solved from transport equations. The governing differential equations in the "sigma" transform coordinate system are solved by finite volume method on unstructured grid of quadrilateral elements. Boundary condition of water level or flow will be imposed on open boundary. For suspended sediment concentrations in the injected phase, suspended sediment concentrations are applied and the outflow phase applies free drainage conditions. This method of calculation was tested with the problem of curved channel sediment transport which was studied experimentally by Odgaard and Bergs. Calculation results are quite consistent with the measured data. In order to test the practical applicability, this method is also tested with the problem of sediment transport in Cu lao Pho islet on Dong Nai river. To solve the matter of hydraulic boundary condition of this problem, the model of Cu lao Pho islet is integrated into the Sai Gon - Dong Nai river system model. Results of the calculation of the river bed evolution of the Cu lao Pho islet on the Dong Nai river also show that this calculation method gives results consistent with the rule and can be used in practical research
An A2O-MBR system for simultaneous nitrogen and phosphorus removal from brewery wastewater
Anaerobic/Anoxic/Oxic – Membrane BioReactor (A2O-MBR) system was used to enhance simultaneous removal of nitrogen and phosphorus from brewery wastewater. The A2O unit containing microorganisms with short solids retention time (SRT) was employed mainly for removal of organic matter and phosphorus together with denitrification. The MBR containing microorganisms with long SRT was employed mainly for nitrification of NH4+-N and recirculation of NO3--N. The model of A2O-MBR system made from polyacrylic with the capacity of 49.5 liters was operated with hydraulic retention times decreased from 24, 18 to 12 hours corresponding to organic loading rates increased from 0.50, 0.75 to 1.00 kg COD/m3.day. The results showed that the model not only treated organic matter well but also nearly completely removed both nitrogen and phosphorus. For all three loading rates, chemical oxygen demand (COD) concentration decreased significantly in the anaerobic and anoxic compartments of the A2O unit, indicating that most of organic matter was utilized in the anaerobic and anoxic compartments for phosphorus release and denitrification, respectively. Nitrification in the MBR was almost perfectly completed, with average NH4+-N removal efficiencies of over 98%. Denitrification in the anoxic compartment happened as much as possible. Demands for the development of PAOs, which were responsible for enhanced biological phosphorus removal (EBPR) processes, could be provided. For loading rate of 0.75 kg COD/m3.day, treatment efficiencies of COD, NH4+-N, total nitrogen (TN) and total phosphorus (TP) of the model were the highest as 95.4, 99.2, 86.7 and 84.6%, respectively. Output values of these parameters were within the limits of Vietnam National Technical Regulation on Industrial Wastewater (QCVN 40:2011/BTNMT), column A. The model of A2O-MBR system was capable of achieving effluents with very low nitrogen and phosphorus concentrations from brewery wastewater
Application of GIS and remote sensing to build up a map of environmental geological suitability for residential buildings on Thi Vai river basin
Geological environment zonation is to divide the areas into relatively homogeneous units based on their natural factors such as hydrology, topography, geology, disasters... to create geoenvironmental units which suit a specific type of xploitation for the purpose of research or regional management. This study presents a process of integrating GIS and remotely sensed data to develop a map of environmental geological zonning for the planning of development of the efective and safety construction sites. Data used in this work include Landsat 8 satellite image classified by application of Fuzzy Logic method to build the map of land use status which includes construction sites, and the GIS data including geology, topography, engineering geology and hydrogeology. The result from this process of integration is the suitability maps of appropriate units for the development of construction sites on the Thi Vai river basin. This map shows 3 different levels of geological environmental condition for development of the construction sites. This result demonstrates the efficiency of the integration of GIS and remote sensing to build tools to assist for the environmental capacity management, for data analysis, and beyond, to identify and incorporate the influencing factors to the subjects of management or research
Application of groundwater quality index (GWQI) and principle component analysis (PCA) to assess the groundwater quality of Pleistocene aquifer in Tan Thanh district, Ba Ria – Vung Tau province
This research applied the groundwater quality index (GWQI) and principal component analysis (PCA) for assessing pollution levels and factors effecting groundwater quality of Pleistocene aquifer in Tan Thanh district, Ba Ria – Vung Tau province. Seventeen wells were colected in April (dry season) and October (rainy season) during 5 years (2012-2017). Nine parameters of water (pH, TDS, độ cứng, Cl-, F-, NO3-, SO42-, Cu2+ và Fe2+) were collected for analyses. The results of GWQI (dry season) divided into 17 wells in dry season with groundwater quality from good to very good which occupied to 82% databases, compared to 94% of rainy season. Meanwhile, the number of wells significantly changed from poor to very poor water between two seasons. PCA demonstrated that two specific factors, interaction of chemical components in river sediments and character of aquifer and anthropogenic, affected to the quality of groundwater in this study area. These explained 65.555% (dry season) and 61.562% (rainy season) of the variances. This result is provided specific information, and the useful tools in order to deal with the complicated databases, as well as zone the groundwater quality in the study area. This further help the authorities to plan suitable strategy for groundwater quality management.
Air emission inventory and application TAPM-AERMOD models to study air quality from 34 ports in Ho Chi Minh City
The port system of Ho Chi Minh City including 34 ports, serves as the gateway to the South (including the South East and the Mekong Delta) in export and import activities. In which contribute a huge amount of pollutants to the atmosphere in Ho Chi Minh City. The objective of this study is to: (i) Calculating air emissions from ports system in Ho Chi Minh city using the SPD-GIZ model which emits a large amount of air pollutants such as sulfur oxide (SOX), nitrogen oxide (NOX), fine dust (PM2.5, PM10), volatile organic compounds (VOC), carbon monoxide (CO) from large ships (Ocean going vessels - OGVs), towing ships (Harbor Crafts - HCs), cargo handling equipment (Cargo handling equipment - CHE) and other vehicles (Heavy trucks – HVs); (ii) Using dispersion model TAPM-AERMOD to assess the impact of port operations to air quality in surouding port area; (iii) Proposing abatement measures based on the results of simulation to reduce emissions/ air pollution levels. The results of emission inventory show that the total port emissions are largely NOX and SOX mainly from large ships (OGVs) and cargo handling equipment (CHE) due to the use of heavy oil and diesel which have high sulfur content. The results show that the time at which a mooring boat is the most time consuming (accounting for over 90% of total emissions from OGVs).
Importance and contribution of surface water and groundwater resources in GDP growth and economic structure of Ho Chi Minh City
Water is essential to life, making its total economic value immeasurable. At the same time water is a finite resource, and one for which competition is likely to increase as the Ho Chi Minh City’s economy grows. Driven by this heightened competition, the economic value of water will rise, and decision-makers in both the private and the public sectors will need information that can help them maximize the benefits derived from its use. This report is an initial step toward (1) raising awareness of water’s importance to our city economic welfare, and (2) assembling information that is critical to sustainably managing the city’s water resources. It emphasizes the analysis of the contribution of two important inputs to economic sectors: labor and water use; calculate the index of economic water productivity and show the necessary interventions in the face of water shortage.
Analysis of riverbank changes in Ho Chi Minh city in the period 1989 – 2015
Abstract—The objective of this study was to analyze the changes of riverbanks in Ho Chi Minh City for the period 1989-2015 using remote sensing and GIS. Combination of Modified Normalized Difference Water Index (MNDWI) and thresholding method was used to extract the river bank based on the multi-temporal Landsat satellite images, including 12 Landsat 4-5 (TM) images and 2 Landsat 8 images in the period 1989-2015. Then, DSAS tool was used to calculate the change rates of river bank. The results showed that, the processes of erosion and accretion intertwined but most of the main riverbanks had erosion trend in the period 1989-2015. Specifically, the Long Tau River, Sai Gon River, Soai Rap River had erosion trends with a rate of about 10.44 m/year. The accretion process mainly occurred in Can Gio area, such as Dong Tranh river and Soai Rap river with a rate of 8.34 m/year. Evaluating the riverbank changes using multi-temporal remote sensing data may contribute an important reference to managing and protecting the riverbanks.
Study on assessment of indigenous knowledge in adapting to floods of farmers in An Giang province
This research was carried out to systematize and assess the appropriateness of farmer’s indigenous knowledge and their ability adapt with the flood in An Giang province, results of the research will provide a scientific foundation for proposing solutions to conserve and enhance the use of indigenous knowledge in reducing the vulnerability of people living in flooded areas. The results showed that local people used several effective indigenous knowledges for adapting with floods. However, the valuable indigenous knowledge has not been recorded yet, nor documented in written materials for sharing to young generations and communities; some indigenous practices are not suitable with the current requirement for flood adapation strategies. Research results showed that (LVI) of diffirent Zone (upper zone, middle zone, lower zone) are decreasingly dependent on major components of social networks, knowledge and skills, natural resources, finance and incomes, livelihood strategies, natural disater and climate variability. In which, (LVI: 0.390) of Phu Huu commune in An Phu district which locates in the upper zone is higher than LVI of two communes located in the lower part of the river. These communes are Vinh An commune (LVI: 0.287), Chau Thanh district (middle zone) and Vinh Phuoc commune (LVI: 0.331), Tri Ton district (lower zone) and adaptive capacity of Phu Huu commune (0.399) is also higher than Vinh An (0.299) and Vinh Phuoc (0.337). It reflects the direct proportion between LVI and adaptive capacity. The research also suggests some solutions to conserve the valuable indigenous knowledge in adapting to climate change of local people.
The value of surface water resources in the socio-economic development of Ho Chi Minh City
Surface water sources in Ho Chi Minh City (HCMC) are being exploited for various purposes such as water supply for daily life, industry and services ; irrigation, animal husbandry, aquaculture ; navigation, environmental landscaping, waste reception and assimilation, etc. Each of these uses has its own benefits and values. However, up to now, the economic value of these water resources has not been fully appreciated and evaluated objectively. This paper presents an overview of the economic value of water resources and the economic valuation of some of the typical value types used in HCMC by 2016, including use for living, industrial, service, irrigation, transportation and environmental landscape
Evaluating salinity intrusion in estuaries using remote sensing data integrated in-situ observation
Saline intrusion reduces crop productivity, causes land degradation, decreases water quality, and severely affects agricultural production, the environment as well as livelihoods. Under the evolution of climate change and human activities from the upstream of the Mekong, the downstream areas of Dinh An and Cung Hau estuaries in Tra Vinh province are also significantly affected by saline intrusion from the East Sea. This article presents the integrated solution of remote sensing and GIS in monitoring and mapping salinity intrusion. The data used are Landsat 8 satellite images combined with salinity water monitoring data collected from actual observation stations during the dry season. Analysis showed that there was a statistically significant correlation between the observed salinity value of the water and the pixel value of the first principal component image. Simulation of spatial distribution from the study indicates that saline intrusion is now entering the interior with a distance from the estuary to about 30 - 48 km depending on the time of the dry season. The results of this study will assist managers in planning food safety strategies at the risk of saline intrusion.
Integrated assessment of the natural conditions on suitability and adaptation of the project of conversion of dipterocarpaceae forest into rubber plantation in Dak Lak province
The results of surveys, investigation and assessment show that the climate conditions of dipterocarpaceae forests are relatively suitable for the growth and development of rubber trees. However, there are some rather severe indicators such as seasonal rainfall distribution, low humidity, inundation in rainy season and drought in the dry season; High and low temperatures reach the limit for the requirement of rubber trees. Most of dipterocarpaceae forest area consists of sandy or sandy soil, discrete soil texture, poor humus, poor water and nutrient retention, rapid heat absorption and transfer, at depths away from the surface of 20 - 40 cm is tombstone and gravel layer, under the clay, easily cause local inundation in the rainy season. The proportion of dipterocarpaceae forest land, which suitable for rubber trees is quite low, with the majority of adaptation levels S2 and S3, no suitable area at S1 level. In the first 2 years, the growth of rubber trees in dipterocarpaceae forest is less than that of rubber in upland fields, cleared land from evergreen forest, semi-evergreen forest. From the third year onwards, the difference in expression is clearer, in that the rubber tree’s diameter on the soil of the dipterocarpaceae forest is lower than that of the traditional rubber plantation at the same age.
Evaluate of air pollution dispersion and propose planning scenerios to reduce air pollution for livestock activities in Tan Thanh district, Ba Ria - Vung Tau province
Livestock is one of the main activities of the agricultural sector in Tan Thanh district, Ba Ria – Vung Tau province. Beside of pollution sources such as waste water, solid waste, livestock activity in Tan Thanh district, Ba Ria - Vung Tau province in recent years has caused air pollution in the livestock area and surrounding area. This research was carried out to evaluate the process of air pollution dispersion from livestock activities based on applying the TAPM meteorological model and AERMOD air quality model. The results showed that the maximum concentrations of air pollutants from livestock area such as NH3, H2S and CH3SH exceeded the National Technical Regulation on Ambient Air Quality (average hour) in the centre of Tan Thanh district, such as Toc Tien commune, part of Tan Phuoc and Phuoc Hoa communes, is 505 μg/m3; 57.4 μg/m3 and 111 μg/m3, respectively. Phu My district and other suburban communes (Hac Dich, Song Xoai, Chau Pha, Tan Hoa, Tan Hai, My Xuan, etc.) have distribution of lower concentrations of air pollutants. Base on the present results of modeling, the authors have proposed livestock development scenarios to control air pollution from this activity, contributing to environmental protection for Tan Thanh district.
Assessment of capacity of using sentinel-1 images in monitoring land subsidence in Ho Chi Minh City
Permanent Scatterer InSAR (PSInSAR) technique is used commonly to evaluate land subsidence for some cities in the world and the pilot project in Ho Chi Minh City has shown the capability of this technique for mapping land subsidence in the period from 2006 to 2010. The result shows that PSInSAR can be applied to study the land subsidence phenomenon more efficiently than any traditional methods. However, SAR data often are commercial images such as ERS, ALOS, COSMO SkyMed… that a large number of SAR scenes must be collected to ensure the best results. This paper introduces results of the average subsidence velocities in Ho Chi Minh City that PSInSAR technique is applied to process SAR data from Sentinel-1 and COSMO SkyMed satellite. Evaluating the preliminary result showed that the capacity of using free Sentinel-1 images to replace commercial images for monitoring land subsidence
Modifying chitosan with n-butyl acrylate - antibacterial ability
Polymer deriving from nature as Chitosan, which is one of the most abundant natural polymers in the world has effectively antibacterial potentiality. However, chitosan is relatively difficult for applications due to its disadvantageous properties. In this article, modifying chitosan (CS) is the grafting copolymerization using monomer n-butyl acrylate (BA) and tert-butyl hydroperoxide (TBHP) as an initiator. This process purposes to attain product having lower glass transition temperature (Tg) than original chitosan causing a wide range of applications but still keeping the capability of being an excellently antibacterial agent. The effects of parameters on synthesizing copolymer were studied by determining the grafting percentage (G%) and grafting efficiency (E%). The results revealed that the highest G = 242% and E = 61% were obtained at the conditions as following: BA/CS = 4 w/w, TBHP/CS = 5 v/w with [TBHP] = 20mM, [CS] = 0.75% w/v in acetic acid 0.6% and reaction temperature 90°C in 6 hours.
AnaAn Ana-Ano-MBR MBR system for nutrient system for nutrient system for nutrient system for nutrient system for nutrient removal from brewery wastewater at various removal from brewery wastewater at various removal from brewery wastewater at various remo
Anaerobic and anoxic variations were combined with membrane bioreactor to form an Anaerobic/Anoxic configuration in MBR-based (Ana-Ano-MBR) system for improving the system performance in terms of organic degradation and nutrient removal from brewery wastewater. The model of Ana-Ano-MBR system made from polyacrylic with the capacity of 42 liters was operated with organic loading rate of 0.75 kgCOD/m3.day. The results showed that for the nitrate recycling ratios of 100, 200, 300%, average NH4+-N and TN removal efficiencies of the model were 95.1 and 76.6, 98.5 and 89.6, 98.9 and 90.2%, respectively, and the output values of NH4+-N and TN were within the limits of Vietnam National Standards (QCVN 40:2011/BTNMT, column A). Treatment efficiencies of COD and TP were over 90% and below 60%, respectively, during the whole experiment period. Low phosphorus removal efficiency was the drawback of Ana-Ano-MBR system due to the lack of appropriate system configuration and operational conditions for PAOs’ growth and activity.
Application of remote sensing and GIS for assessing the urbanization trend in Can Tho city
This paper presents the method of integrating remote sensing and GIS to analyze the urbanization trend through the impervious surface change in Can Tho City. The impervious surface maps were created from the multi-temporal LandSat images in 1997, 2005, 2010, 2016 and were overlaid in GIS to extract the urban expansion from 1997 to 2016. The results showed the urban area of Can Tho increased from 1506,638 ha in 1997 to 5611,114 ha in 2016, average growth rate of 14,3%/year. The integration of remote sensing and GIS was found to be effective in monitoring and analyzing urban growth patterns.
Identify soil acidification due to reclamation of coastal potential acid sulfate soils from shrimp farming activities in Can Gio, Ho Chi Minh City
Soil acidification is one of the top concerns of the coastal wetland areas. In recent decades, by reclamation of coastal potential acid sulfate soils for agricultural activities (rice field, shrimp farming,...), humans have caused soil acidification. pH and the presence of secondary iron minerals (hematite, goethite) and ferric iron minerals (jarosite, schwertmannite, copiapite) are considered as the indicators of acidic soil. This study is to rapidly detect acidic status of soil through identifying secondary iron minerals by characterized band ratios. Sentinel-2A data with B4/B2 and B11/B8 can determine iron oxides and ferric iron minerals. The identified spectral result of fallowed ponds on ratio images shows the correlation with measured pH and mineral composition data (XRD). This research promises applicability of used band rationing method as well as potential of Sentinel-2A data in monitoring soil acidification in coastal wetland areas.
Post-biological treatment of yeast production wastewater using non-thermal plasma
Yeast production wastewater is one of the complex wastewater types, characterized by high organic content and color. This research on the application of non-thermal plasma in laboratory scale yeast production has demonstrated the superiority of this technology in terms of efficiency, treatment time and non-selectivity for pollutants. The wastewater treatment model is optimized in 3 minutes with a DC voltage of 100 V and a pH around 8.4, resulting in COD removal efficiency of over 75%, while color and TSS removal of 93%. The results of this study are the basis for practical application of wastewater at AB Mauri Vietnam after biological treatment stage (anaerobic, anoxic and aerobic) with a COD of greater than 5,000 mg/l and color over 26,000 Pt-Co.
Studying and proposing measures to reduce CO emissions from biomas boilers for reducing air pollution and saving energy
Removal of CO is practically required for reducing air pollution and saving energy from boiler combustion processes. According to the survey results, high CO emissions during boiler operation process is directly related to the combustion mode: 80% all of fuel input are carried out manually, 80% all of boilers are operated by the experiences of workers – 20% of them has automatic operation mode or pre-set software; The manual operation of forced draft fan and induced draft fan with and without inverter leads to the unequal air distribution and inefficiency combustion which are the causes of high CO emission. In this study, based on the structure and operation of the existing boiler to reduce the CO emission during the operation of boiler, the proposed option is to adjust the combustion mode by adjusting the fan speed through installed inverter, adjusting operation mode and cleaning boiler, cleaning the flue gas treatment system... Research results showed that it is possible to reduce CO emissions by adjusting the combustion regime.
Development of a method to identify inter-regional environmental incidents associated with the oil spills in HCM City and the neighboring provinces
The inter-regional incidents associated with the oil spill is increasingly a serious problem to the industrial developing countries, like Vietnam. In this study, a multi-criteria analysis process was proposed to identify petroleum depots that represent potential inter-regional oil spill incidents in Ho Chi Minh City and the neighboring provinces. The criteria for determining the inter-regional inccidents asscociated with oil spill comprise of a number of criteria sets such as oil spill hazard criteria, inter-regional hazard criteria, oil spill damage criteria. Hierarchical analysis (AHP) has been applied for identifying the importance factor of the criteria. The total risk of inter-regional oil spill incidents are then estimated to provide effective support to the risk management and response plan
Application of Magnetite Zn/Al Layered Double Hydroxide (Fe3O4 Zn/Al LDH) on the Removal of Organic Matter in Supplying Water
In this study, magnetite Zn/Al layered double hydroxide (LDH) composite has been synthesized through the chemical co–precipitation method. Raw water samples of Thu Duc and Tan Hiep water plant were also collected and analysed, they were used as the object to investigate dissolved organic compounds (DOC) adsorption capacity of the material. The results of DOC empirical adsorption experiments in raw water samples of Thu Duc and Tan Hiep water plants also show that the adsorption processes reach high efficiencies when the sample solutions are adjusted to pH from 5 to 6. After 21 hours, the adsorbent in column loses its adsorption ability with the corresponding adsorption capacity of 8.12 mg/g.