Photochemical Smog Modelling Using the Air Pollution Chemical Transport Model (TAPM-CTM) in Ho Chi Minh City,Vietnam

Environmental Modeling & Assessment - This paper describes the application of the air pollution model (TAPM-CTM) for photochemical airshed modelling in the Ho Chi Minh region. The model was...     

Measuring water resource use efficiency of the Dong Nai River Basin (Vietnam): an application of the two-stage data envelopment analysis (DEA)

Environment, Development and Sustainability - The recent growth of agriculture, industry and urban areas in Vietnam requires a large amount of water consumption as a production factor. This paper...     

Application of SWAT model to assess land use change and climate variability impacts on hydrology of Nam Rom Catchment in Northwestern Vietnam

Environment, Development and Sustainability - Land use and land cover (LULC) changes, climate variability and climate change (CC) contribute hydrological response in tropical catchments, but their...     

Integrated environmental assessment and pollution prevention in Vietnam: the case of anthracite production

Using the concept of life cycle analysis, the whole life cycle of anthracite production in Vietnam was assessed and the environmental “hot-spots” were identified. These include (i) dust pollution at coal transfer points or piles in storage; (ii) noise pollution resulting from the usage of heavy equipment, and (iii) high volume of acid and turbid mine water discharged into the environment.Pollution prevention and treatment options were identified and discussed in this study which consists of wet treatment of dust, planning, collection and treatment of mine water, planting of trees for dust and noise reduction as well as minimization of erosion. Some recommendations are made for pollution abatement from coal production and improvement of anthracite production in the region.     

Spatiotemporal changes and fragmentation of mangroves and its effects on fish diversity in Ca Mau Province (Vietnam)

Mangroves are important economically and ecologically, however mangrove cover has declined dramatically leading to habitat fragmentation and biodiversity loss. Information on mangrove cover change, fragmentation and impacts on fish diversity is poorly understood. The aims of this study are to detect spatiotemporal changes and mangrove status, examine fragmentation changes and associated effects on fish diversity. Landsat images in1989, 2000, and 2013 were used to classify mangrove cover in Ca Mau Province (Vietnam) and validated against high resolution Pleiades imagery. Fragmentation changes in mangrove cover were examined using series of landscape metrics evaluated against fish diversity indices (Simpson’s index, Jaccard’s coefficient and relative abundance). Results show that mangrove cover has declined 24.6% in the province. Currently, high and moderately dense mangroves distribute in southern half of the region while the low density mangroves occurs in the northern half. Over the 24 year study periods, the number of patches and edge density has increased 58% and 53.9%, respectively, while the mean patch size and mean patch edge has decreased 52.3% and 26.6%. Fish diversity in the more highly fragmented mangrove area was 1.78 times lower than the less fragmented mangrove. The study illustrates the applicability of using Landsat satellite imagery for use in mangrove fragmentation studies as well as the impact of fragmentation.     

Climate change impacts on a large-scale erosion coast of Hai Hau district,Vietnam and the adaptation

Among the effects of global warming, sea level rise (SLR) and severe typhoons pose the greatest threat to the stability of human settlements along coastlines. Therefore, countermeasures must be developed to mitigate the influences of strong typhoons and persistent SLR for coastal protection. This study assesses climate change impacts on coastal erosion, especially in two projected SLR scenarios of RCP2.6 and RCP8.5. The results show that SLR and severe typhoons lead to the increase of coastal erosion, beach lowering and scour. Moreover, as in projected SLR scenarios, average waves in high tide can cause severe soil erosion at inner slopes and lead to dyke failure by 2060. The paper highlights the need for additional countermeasures to protect the coast of Hai Hau district against SLR and severe typhoons. Among the alternatives available for countering these threats, applying soil stabilization and soil improvement combined with geosynthetics are promising strategies for coastal structures. Hybrid structures can be used with earth reinforcement and soil improvement. Additionally, the paper emphasizes the importance of multiple protective adaptations, including geosynthetics and ecological engineering measures against climate change-induced severe erosion on the coast of Hai Hau district.     

Esterification of sugarcane bagasse by citric acid for Pb2+ adsorption: effect of different chemical pretreatment methods

In this study, different pretreatment strategies of sugarcane bagasse prior to citric acid modification were investigated in terms of Pb²⁺ adsorption capacity. Pretreatment strategies included the use of NaOH, HCl, and C₂H₅OH in various concentrations. In order to fundamentally understand how these pretreatment methods affect the modification of sugarcane bagasse by citric acid as well as the Pb²⁺ adsorption capacity of sugarcane bagasse, three main components of sugarcane bagasse namely cellulose, hemicellulose, and lignin were isolated and esterified by citric acid under the same conditions. ATR-FTIR, XPS, SEM, and an analysis of the number of carboxylic acid groups were used to investigate the physicochemical and chemical properties of the materials. These three components were proved to participate in adsorption and induce the esterification with citric acid. Hence, pretreatment with ethanol and 0.01 M NaOH which could retain cellulose, hemicellulose, and lignin in sugarcane bagasse achieved a high Pb²⁺ adsorption capacity, i.e., 122.4 and 97 mg/g after the esterification with citric acid. In contrast, pretreatment with 0.5 M NaOH and 0.1 M HCl removed lignin and hemicellulose, leading to the lowest value of approximately 45 mg/g for citric acid esterified-pretreated sugarcane bagasse. XPS analysis and number of carboxylic group measurement confirmed the esterification between bagasse and citric acid. To understand the adsorption mechanism of adsorbent, two kinetic models including pseudo-first-order model and pseudo-second-order model were applied. The experimental data were well described by the pseudo-second-order model. The adsorption isotherm data were fitted Langmuir and Freundlich.

     

Status of water use and potential of rainwater harvesting for replacing centralized supply system in remote mountainous areas: a case study

Environmental Science and Pollution Research - The failure of the centralized water supply system forced XY community to become more dependent on uncertain and unstable water sources. The results...     

Comprehensive temperature monitoring in an in-vessel forced-aeration static-bed composting process

Comprehensive temperature monitoring was done in an in-vessel forced-aeration static-bed composting process using sewage sludge. The three layers that divided the compost pile horizontally showed different temperature distributions. The temperature of the top layer appeared not to be influenced by the ambient temperature. The temperature of the center area of the top layer was taken to be the representative temperature for evaluating composting start-up performance. The temperature of the bottom layer was strongly influenced by the ambient temperature, and the temperature of the center area of the bottom layer was taken to be the representative temperature for pathogen control as it was the minimum temperature in the reactor. Composting start-up performance was influenced by several factors when the ambient temperature was either below or above 20°C. When the ambient temperature was below 20°C, the time taken to reach 65°C (T ₆₅) was influenced by the temperature of inflowing air, but when the temperature was higher than 20°C, it was influenced by the ratio of sewage sludge to seed compost (F/S). T ₆₅ was least when F/S was 1–2. Received: January 9, 2001 / Accepted: October 10, 2001