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31.
In 1998, the Vietnamese National Assembly approved a Five Million Hectare Reforestation Program, (5MHRP) 1998-2010. It would increase forest cover by some 45%, use barren hills, produce wood, and generate socioeconomic development. It would, however, also put demands on Vietnamese planning. Experiences from a former development project and two case studies from a commune and village are used as a basis for analyzing the planning system. The study describes the objectives and strategies of government and farmers in one commune and one village and analyzes how planning data influence scenarios on future development. Official planning data do not reflect reality but are derived through negotiations. In the commune and village studied, it would be difficult for the 5MHRP to materialize, as most of the forest land, officially not yet used, is actually used for food production. The approach and method used by the study offers alternatives to current planning practices. 相似文献
32.
Thang Nguyen Quoc Huy Bui The Khanh Dang Nguyen Nha Vy Ngo Thi Tuong Phuong Tran Ha Sy Do Trung Tham Le Thi Phuong Nguyen Thi Kim 《Environmental science and pollution research international》2021,28(39):54960-54971
Environmental Science and Pollution Research - This study aimed to evaluate the health risks of cadmium (Cd), lead (Pb), inorganic arsenic (As), and nitrate exposure through the consumption of... 相似文献
33.
Claudia Ringler Nguyen Vu Huy Siwa Msangi 《Journal of the American Water Resources Association》2006,42(6):1465-1482
Abstract: Recent water sector reforms and increased scarcity and vulnerability of water resources, combined with declining public funding available for large scale infrastructure investment in the sector, have led to a greater awareness by the Government of Vietnam for the need to analyze water resource allocation and use in an integrated fashion, at the basin scale, and from a perspective of economic efficiency. In this study we focus on the development, application, and selected policy analyses using an integrated economic hydrologic river basin model for the Dong Nai River Basin in southern Vietnam. The model framework depicts the sectoral structure and location of water users (agriculture, industry, hydropower, domestic, and the environment) and the institutions for water allocation in the basin. Water benefit functions are developed for the major water uses subject to physical limitations and to constraints of system control and policy. Based on this modeling framework, we will analyze policies that can affect water allocation and use at the basin level, including both basin-specific and general macroeconomic policies. 相似文献
34.
Saikat Sinha Ray Shiao-Shing Chen Dhanaraj Sangeetha Hau-Ming Chang Cao Ngoc Dan Thanh Quang Huy Le Hong-Ming Ku 《Environmental Chemistry Letters》2018,16(4):1247-1265
Membrane technology has become a common separation technology over the past decennia. Membranes are used more and more for the production of drinkable water from groundwater, surface water and wastewater. Membranes are now competitive versus conventional techniques. Desalination is predominantly used to eradicate the problem of water scarcity. The sustainability of all desalination processes depends mainly on the reduction of energy costs (production cost) and the increase in water recovery. Forward osmosis and membrane distillation are emerging technologies for sustainable desalination. Here we review membrane processes of forward osmosis and membrane distillation and the advancements in membrane material and modules. We also discuss the capability of membrane distillation in treating highly concentrated aqueous solutions derived from other desalination processes. Furthermore, the advancements in fabrication of high-performance membrane is reviewed and the performance of different membranes and optimization of membrane distillation process are summarized. 相似文献
35.
Ha Ngoc Hien Bui Huy Hoang Tran Thi Huong Tran Thanh Than Pham Thi Thu Ha Ta Dang Toan Nguyen Minh Son 《Environmental Modeling and Assessment》2016,21(2):261-277
This paper presents simulations of climate change impacts on water quality in the upstream portion of the Cau River Basin in the North of Vietnam. The integrated modeling system GIBSI was used to simulate hydrological processes, pollutant and sediment wash-off in the river basin, and pollutant transport and transformation in the river network. Three projections for climate change based on emission scenarios B1, B2, and A2 of IPCC Special Report on Emission Scenarios (SRES) were considered. By assuming that the input pollution sources and watershed configuration were constant, based on 2008 data, water quality in the river network was simulated up to the terminal year 2050. For each climate change scenario, patterns of precipitation in wet and dry year were considered. The change in annual and monthly trends for dissolved oxygen (DO), biochemical oxygen demand (BOD), and ammonium ions (NH4+) load and concentration for different portions of the watershed have been analyzed. The results of these simulations show that climate change has more impact on changing the seasonal water quality parameters than on altering the average annual load of the pollutants. The percent change and change pattern in water quality parameters are different for wet and dry year, and the changes in wet year are smaller than those in dry year. 相似文献
36.
In the water treatment field, activated carbons (ACs) have wide applications in adsorptions. However, the applications are limited by difficulties encountered in separation and regeneration processes. Here, activated carbon/Fe3O4 nanoparticle composites, which combine the adsorption features of powdered activated carbon (PAC) with the magnetic and excellent catalytic properties of Fe3O4 nanoparticles, were fabricated by a modified impregnation method using HNO3 as the carbon modifying agent. The obtained composites were characterized by X-ray diffraction, scanning and transmission electron microscopy, nitrogen adsorption isotherms and vibrating sample magnetometer. Their performance for methyl orange (MO) removal by adsorption was evaluated. The regeneration of the composite and PAC-HNO3 (powdered activated carbon modified by HNO3) adsorbed MO by hydrogen peroxide was investigated. The composites had a high specific surface area and porosity and a superparamagnetic property that shows they can be manipulated by an external magnetic field. Adsorption experiments showed that the MO sorption process on the composites followed pseudo-second order kinetic model and the adsorption isotherm date could be simulated with both the Freundlich and Langmuir models. The regeneration indicated that the presence of the Fe3O4 nanoparticles is important for a achieving high regeneration efficiency by hydrogen peroxide. 相似文献
37.
Efficient nutrient removal in decentralized wastewater treatment systems is a challenging task. To improve the removal of organic matter and nitrogen from wastewater, two types of bioreactors using membrane-aerated biofilm reactor (MABR) and microbial fuel cell (MFC) techniques were evaluated. During more than 250 days of continuous-flow reactor operation, both reactors showed consistently high chemical oxygen demand removal (>86%). At an influent ammonium-nitrogen (NH4(+)-N) concentration of 30 mg N/L, the average effluent NH4(+)-N concentrations were 6.2 and 0.5 mg N/L for the MABR and MFC reactor, respectively, while the effluent nitrate-nitrogen (NO3(-)-N) concentrations were 5.4 mg/ L in the MABR and 19.2 mg/L in the MFC-based reactor. The overall total inorganic nitrogen removal efficiencies were 64% and 36% for the MABR and MFC reactor, respectively. At the measured dissolved oxygen concentrations of 5.2 and 0.23 mg/L in the aerobic/anoxic zone of the MFC and MABR, respectively, a specific oxygen uptake rate of 0.1 g O2/g VSS-d, resulting from ammonia oxidation, was detected in the settled sludge of the MFC, while no nitrifying activity of the sludge from the MABR was detected. Molecular microbial analysis demonstrated a link between the bacterial community structure and nitrifying activity. The relatively high abundance of Nitrosomonas europaea was associated with its detectable nitrification activity in the settled sludge of the MFC. The results suggest that MABR and MFC techniques have the potential to improve organic and nitrogen removal in decentralized wastewater systems. 相似文献