Science & Technology Development Journal: Science of the Earth & Environment

Applying multi-criteria analysis tools (AHP, SAW) combined with GIS to analyze the reasonableness of mineral resource exploitation in Phu My town, Ba Ria – Vung Tau province

Cuong Tan Le — 2024-12-31

Mineral resources play a crucial role in infrastructure development and serving socio-economic development but also lead to consequences of non-renewable resource depletion and negative impacts on the environment and society. Therefore, some studies establish appropriate indexes to analyze and evaluate the reasonableness of exploiting mineral resources. This study approaches the multi-criteria analysis method (MCDM) and geographic information system (GIS) to analyze and evaluate the reasonableness of exploiting mineral resources. The reasonableness index is established based on 03 component indexes related to mining conditions, economic and social, and environmental protection, estimated based on 03 sets of criteria and corresponding weights. The study investigated, interviewed 114 relevant subjects, and evaluated 25 mine sites planned to exploit mineral resources in Phu My town, Ba Ria - Vung Tau province. Research results have shown that the reasonableness of each mine site is classified as Very high, high, medium, and low, accounting for 28%, 36%, 24%, and 12%, respectively. Based on the analysis and direct consultation with managers, 03 solutions to improve the reasonableness of exploiting natural resources were proposed. In addition, the research results also support managers and policies in making decisions related to ensuring harmony and reasonableness between exploitation and use of resources with environmental protection.

Building a map of urban ecosystem services in Thu Duc City

Anh Hoang Nguyen — 2024-12-31

The process of urbanization brings numerous positive impacts on economic and social development; however, it also exerts significant effects on the natural environment. Specifically, urbanization has contributed to the disruption of many natural ecosystems, which play a vital role in filtering pollution and safeguarding the living environment. Thu Duc City serves as a case study, where rapid urbanization has led to substantial changes in its natural ecosystems. Many ecosystems have been degraded or lost, reducing their capacity to provide valuable ecosystem services such as carbon sequestration, climate regulation, and pollution mitigation. This study aims to evaluate the condition of natural ecosystems in Thu Duc City and analyze the ecosystem services they provide. The research involves the creating of an ecosystem service map system over the period from 1988 to 2023, employing the Analytic Hierarchy Process (AHP) method in combination with GIS and remote sensing technologies. The study’s findings reveal that the conversion of land use types from agricultural land to urban areas has significantly diminished the capacity of ecosystems to provide essential services. These results provide a critical foundation for urban planning and environmental conservation efforts in the region.

Measuring circularity performance based on the material circularity indicator for a circular economy in the seafood processing plant

Tran Trung Kien — 2024-12-31

In this study, a circular economy model for seafood processing factories was proposed. The proposed solutions are based on previous studies on waste conversion techniques combined with the actual emission status of the factory. Besides, the Material Circularity Indicator (MCI) has been established and applied to the proposed circular economy system to evaluate the efficiency of waste conversion techniques. The MCI index will be used to calculate efficiency and circularity for all discarded waste to evaluate the environmental and economic effectiveness of the circular economy system. Results show that the level of recovery is higher than the level of recycling, but the difference is not too great, which shows that these are potential products, easy to recover without much loss, especially in recycling. Notably, only the water that is imported to be used to wash materials is 80% recycled. So the Fr of water has a value of 0.8. The remaining 7 waste products are 100% raw materials, with no recycled ingredients, so the Fr of these 7 products has a value of 0. The low percentage of input materials from recycled sources is because of the products. This is a waste product. A more concrete finding is that the circular economy model changes many of the fundamentals in the system compared to the current linear economic system. Therefore, some negative impacts will occur if businesses choose to switch to a circular economy system.

Assessment and zoning of economic damage risk due to the inundation in Thu Duc City on the period 2021-2022

Diep Ngoc Nguyen — 2024-12-31

Thu Duc City directly under Ho Chi Minh City was established in 2020 on the basis of merging 3 districts (Thu Duc District, District 2 and District 9). Since its establishment, Thu Duc City has faced widespread urban flooding caused by both rain and tides. The impacts of urban flooding cause many adverse influences on people living and trading in the Thu Duc City. Inheriting the study on economic damage due to inundation in Ho Chi Minh City in the period 2016-2019, the project inherits the survey forms to conduct surveys and the flood’s and damage’s formulas to assess economic losses of people living there. The surveys of the inundation and the economic damages caused by floods are implemented in all wards of Thu Duc City in the period 2021-2022. The results of the study show that the distribution of inundation, economic damage level as well as the flood-damage risk level due to the inundation are concentrated in densely populated areas and riverside areas. It also shows that the level of economic damage in the period 2021-2022 is much reduced compared to the period 2016-2019 by about 25-30% and at the low level. The main reasonable of explanation about the reduction of risk level in the period 2021-2022 is the decrease of City’s economic due to the serious disease Covide 19. The citizen’s incomes reduced. Their works are delayed and the movement limitted. So that, the indirect economic damages also significantly being lower than the previous. Through establishing a flood and damage survey form, the study hopes to update more information and contribute a "way" to assess damage caused by floods directly to the urban management agencies of Thu Duc City.

Assessing the effect of operating factors on phosphate removal by electrocoagulation process using Response Surface Methodology

Huynh Thi Ngoc Han — 2024-12-31

This study investigated the electrocoagulation batch model with two aluminum plate electrodes. The effect of operating factors on phosphate removal efficiency by electrocoagulation process using aluminum electrodes was evaluated by Response Surface Methodology (RSM), including current density, pH, initial phosphate concentration, and reaction time. A total of 15 experiments were set up following the Box-Behnken method in Design – Expert 12 software, with three center points. The optimal operating conditions were determined by analyzed collected data in Design – Expert 12 software: current density of 16.7 A/m2, pH 5.6, reaction time of 33.5 min, and initial phosphate (P-PO43-) of 66.249 mg/L. The correlation equation between treatment efficiency and factors was also determined as a quadratic model with R2 = 0.9771. The interaction between the pairs of factors significantly affected P-PO43- treatment efficiency, represented by 3D surface plots. The maximum P-PO43- treatment performance was reached 99.6%. The treatment efficiency of real livestock wastewater was determined and reached a high agreement with the predicted value, 99.7% after 30 min. Generated sludge was evaluated, approximately 6.3±0.76 kg per 1 m3 treated wastewater.

The trend of salinity changes at coastal stations in The Mekong Delta during the period 1996-2018

Nguyễn Thị Huyền Trân — 2024-12-31

The Mekong Delta (MKD) is increasingly suffering from the adverse effects of saline intrusion, primarily due to climate change-sea level rise (SLR), upstream hydropower development, and mangrove forest degradation. This study focuses on using statistical methods to assess salinity changes, by determining the frequency of salinity through ANOVA variance analysis and frequency analysis based on data series from 1996 to 2018 at monitoring stations. The results show that the increasing trend of salinity (at Binh Dai, Ben Trai, Loc Thuan, Huong My, Son Doc, An Thuan, Hung My, Tra Vinh, Cau Quan, Long Phu, Dai Ngai, Phuoc Long, Ganh Hao, CaMau) accounts for 70%, while the decreasing trend of salinity (at Hoa Binh, Vam Kenh, Tra Kha, Tran De, Soc Trang, Song Doc) accounts for 30%. Regarding to frequency analysis, at a frequency of 90%, the stations (Phuoc Long, Ganh Hao, Ca Mau, Song Doc) exceed 33‰, and at a frequency of 95%, the stations (Tran De, Phuoc Long, Ganh Hao, Ca Mau, Song Doc) exceed 33‰. The study's results, which determine the trend of salinity changes, provide a database for further in-depth research as well as support for disaster management efforts concerning local saline intrusion.

Risk assessment of groundwater contamination and usage restrictions zoning in Tay Ninh province

Linh Khánh Lưu — 2024-12-31

The upper-middle Pleistocene (qp2-3) aquifer in Tay Ninh province is the primary source of supply for drinking and domestic purposes. In this study, the risk of contamination (RC) was calculated and zoned considering groundwater vulnerability assessment (GOD) and contamination danger index (POSH) in the GIS environment. At the same time, to zone the groundwater quality according to the purpose of use, the study applied the groundwater quality index (GWQI) from the analysis results of 60 water samples in the study area. The results show that the risk of contamination is divided into 3 zones: low, medium, and high, accounting for 63.9%, 26.9%, and 9.1% of the distribution area of the upper-middle Pleistocene aquifer, respectively. The study shows that agricultural areas have a high risk of contamination, while industrial areas have a medium risk of contamination. This result is considered an important tool to support managers in protecting, controlling pollution, limiting exploitation and use activities, and sustainably managing groundwater.