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

Latest Articles

1. Original Research

   Applying life cycle assessment (LCA) and life cycle costing (LCC) tools for waste recovery model in super-intensive shrimp farming system in Ca Mau province

   Nguyễn T.,ắn., Nguyễn T.,ảo Lê Hải Nguyễn T.ảo

   This study aims to evaluate the environmental sustainability and economic efficiency of waste recovery solutions from a typical super-intensive shrimp farming household (shrimp farming on tarpaulin ponds) in Ca Mau province based on on the life cycle assessment (LCA) tool that focuses on assessing greenhouse gas emissions combined with life cycle cost (LCC) for post-recovery products. Options considered to treat wastewater and sludge towards zero emissions from shrimp farming households include: i) wastewater treatment using a system of settling ponds and biological treatment ponds; ii) sludge treatment with biogas tank and composting. The results show that greenhouse gas emissions are mostly in the operating phase (electricity consumed by operating the circulating water pump from the second biological pond to the household's current farming system), accounting for 29.5% compared to other periods. The proposed system of circulating wastewater and sludge solutions for super-intensive shrimp farming shows economic benefits when for every 1m3 of water reused, people benefit 32.22 VND and 1kg of Compost people benefit. benefited 786.67 VND. The limitation of the study is that it has not calculated the amount of greenhouse gases generated from the respiration of animals and aquatic plants participating in the wastewater treatment process in biological treatment ponds. Finally, the CO2 emissions of the auxiliary facilities are calculated for the first farming crop. When the model operates stably for the following years, CO2 emissions will be significantly reduced due to no new construction.

   Published: 2024-03-31In press
2. Original Research

   Improving nitrogen recycling in an aquaponics system by adding a composting process from fish sludge

   Kien T., Le H., Nguyen H., Tran H., Nguyen T., Nguyen T.

   The goal of this research is to recover nutrients from wastewater sludge and recirculate them as organic fertilizer in aquaponics systems. Improving the sustainability of aquaponics by increasing economic and environmental efficiency. In this study, an improved aquaponics system was developed including a fish pond, biological reactor, growing bed, and composting site. In addition, an ecological floating bed is placed on the surface of the fish pond to absorb nutrients in the fish pond. After a farming cycle lasting more than 3 months, the biomass of Cyperus haspan is harvested and mixed with fish sludge from the biological reactor tank to produce organic fertilizer. The nitrogen and carbon balance model was established to evaluate the nutrient recovery efficiency of the aquaponics system. The results indicate that nutrient recovery from fish sludge can also address the problem of nutrient deficiency faced by aquaponics systems and reduce the costs associated with the purchase of additional nutrients. Besides, 32 - 45% of N originating from fish feed is assimilated into plant biomass. It is estimated that about 35-45% of unaccounted N is lost to the atmosphere, the remaining 20-25% into wastewater, and 0.8-3% into solid waste. The average weight of fish harvested in the system is 531±94.2 g/fish with a survival rate of 80%. Plant biomass in three harvests reached 1.8 to 2 kg/m2.

   Published: 2024-03-31In press
3. Original Research

   Implementation of material flow cost accounting (MFCA) to improve waste recovery efficiency for pig farming

   Ngo N., Le H., Nguyen T., Tran H., Nguyen T., Kien T.

   The aim of this study is to analyze and evaluate the circularity of material flows according to the material cost flow accounting (MFCA) approach for an integrated ecological model for small-scale pig farming. MFCA is considered a typical tool for environmental management accounting. The calculation is carried out on an integrated ecological model in An Dinh commune, Mo Cay Nam district, Ben Tre province, with two main initial processes: pig farming and coconut cultivation, and additional connected sub-systems to close the circular ecological loop, including biogas, vermicomposting and biochar systems. Applying material flow analysis, the inflow and outflow of processes are costed. Costs are divided into three groups: material costs, energy costs, and system costs. MFCA calculation results show that, when applying the integrated ecological model, the percentage of lost costs is only 7.87%, compared to 14.08% when not applying the integrated model. The only lost part is dead pigs, which need to be handled and cannot be utilized in any form. Other wastes from one process are turned into resources for another process, bringing dual economic and environmental benefits. Flowing material costs in the research framework clearly demonstrate the benefits of applying Integral Ecology, promoting widespread application by farmers in agricultural production, and implementing green agriculture and circular economies.

   Published: 2024-03-31In press
4. Original Research

   Distribution of microplastics in surface water from Saigon River to Can Gio Sea

   Nguyen N., Nhon N., Hai H., Hien T.

   In recent years, microplastic pollution has emerged as a critical issue that has far-reaching impacts on the environment, organisms, and humans alike. As a result, there has been a growing need for in-depth studies aimed at analyzing and understanding the abundance, physical, and chemical characteristics of microplastics in different environments. This study, conducted in June 2021, sought to do that by examining the prevalence of microplastics in surface water samples from the Saigon River and Can Gio Sea, and comparing their distribution from the river to the sea. The study involved the collection of thirty surface water samples from both the Saigon River and Can Gio Sea, which were subsequently analyzed through the extraction of microplastics from the water samples and identification using infrared spectroscopy. The results of the study showed that microplastics were present in all surface water samples, with an average abundance of 0.80 ± 0.58 pieces/m3 in the Saigon River and 0.24 ± 0.45 pieces/m3 in the Can Gio Sea. These findings highlight the severity of the problem, which affects both freshwater and marine ecosystems. It is noteworthy that microplastics with sizes larger than 1 mm and fragment shape were found to dominate in both sampling areas. Additionally, the study revealed that many colors were found, with white and transparent colors accounting for over 50% of the total microplastic abundance. Comparing the results of this study with the 2020 study conducted by the same research group, it was evident that lightweight plastics such as polyethylene, polypropylene, and ethylene-vinyl acetate continued to play an important role in microplastic pollution in this area. In light of these findings, it is clear that plastic pollution is a pressing issue that demands immediate attention and action. The impact of microplastics on the environment, organisms, and human health is undeniable, and as such, there is an urgent need to develop strategies aimed at reducing their impact.

   Published: 2023-12-31753-763
5. Original Research

   The effect of agricultural waste inhibit the uptake of Cadmium (Cd) by pak choi in assumption conditions of contaminated soil

   Trang L., Tran T.

   This study aimed to explore the effects of agricultural waste (rice straw-RS and maize stalks-MS) in reducing Cd toxicity. Experiments in the study determined: growth of pak choi, total Cd concentration in the plant and the change in distribution of Cd fraction in the soil. Results showed that: agricultural waste application may detoxify Cd at excessive concentrations (3 and 6 mg/kg) by transforming mobile Cd fractions (EXC-Cd and CAB-Cd) into semi-mobile and non-mobile Cd fractions (FEM-Cd, OM-Cd, and RES-Cd); the Cd concentrations in pak choi decreased and pak choi growth increased. However, a significant reduction in Cd concentration can only occur when agricultural waste application is at an appropriate content (20 g/kg). In addition, agricultural waste application promoted the growth of pak choi at lower content (10 g/kg). Furthermore, this study also showed a good correlation between the ratio of mobile Cd fractions (EXC-Cd and CAB-Cd) with Cd concentration in pak choi and plant growth. This study suggested that agricultural waste application, especially rice straw, plays an important role in preventing Cd uptake by plant tissues at excessive concentrations through transformations into immobile Cd fractions.

   Published: 2023-12-31741-752
6. Original Research

   Assessment of water quality in Hau river flowing through Vinh Long province using principal component analysis

   Nguyen A., Tran T., Nguyen T., Le H.

   Water is one of the most important and precious resources for the human life and species, a particularly important factor to ensure the successful implementation of strategies and plans for economic and social development, and to ensure national security. However, water quality is significantly degraded by global climate change and increasing over-exploitation activities. The study assessed the water quality on the Hau River, the part running through Vinh Long province, as an information sourse for the water resources management and protection in this river. Water quality data used in the study provided by the Department of Natural Resources of Vinh Long province at 7 sites on the Hau river. The results show that at most of the monitoring locations, temperature and pH were consistent with the lifespan of aquatic organisms. TSS parameters, and the content of nutrients and organic matter exceeded national water surface standards. Applying principal component analysis (PCA), we investigated the relationship between water quality parameters. The results of PCA analysis showed that COD, BOD5, pH, Coliform, P-PO43-, N-NO3-, TSS, and EC have the key factor on the quality in Hau river flowing through Vinh Long province mainly originating from areas of aquaculture, agricultural and industrial activities. Therefore, it is necessary to include these 8 criteria as the key criteria in the surface water quality monitoring and surveying program of the Hau river flowing through Vinh Long province.

   Published: 2023-12-31715-727
7. Original Research

   Removal of doxycycline antibiotics in water with adsorbents derived from banana peels

   Vo T., D., H., Nguyen V., T., Nguyen T. H.

   This study evaluated the antibiotic removal efficiency of doxycycline (DOX) of biochar prepared from banana peels with different temperatures. Factors affecting antibiotic adsorption (including pH, initial DOX concentration, contact time, biochar dose) were studied. The results show that biochar generated at high temperature (800 oC) and modified by KOH (BP-KOH), has higher antibiotic adsorption capacity than those at low temperature (no pyrolysis and 500 oC pyrolysis, BP and BP500 respectively). The properties of the materials were determined by the scanning electron microscope (SEM), Fourier Transform Infrared Spectroscopy (FITR), zeta potential, and Brunauer–Emmett–Teller (BET) analysis methods. The SEM image shows that the fabricated material contains many pores. FTIR spectra show that the fabricated material contains surface functional groups such as O - H, C - H, C - C, etc. The BET results show that high surface area of BP-KOH (710.214 m2/g). The DOX adsorption capacity (120 mg/L) of BP-KOH obtained a high treatment efficiency of 97.9% with an adsorption time of 1440 minutes (24 h) with an optimal pH of 6. Research results showed found that adsorbent made from banana peel has great potential in the application of antibiotic treatment in water.

   Published: 2023-12-31728-740
8. Original Research

   Research on evaluating the efficiency of recovery nutrients (N, P) in an integrated ecology system for catfish farming

   Kien T., Dong H., Nguyen H., Tran H., Nguyen T., Nguyen T.

   The purpose of this is to evaluate the ability to recover nutrients (N, P) emitted from catfish farming by using an integrated ecological system towards zero emissions. An integrated system has been designed and implemented for a catfish pond with a water surface area of 10,300 m2. Wastewater is treated with water hyacinth, sludge is used for organic fertilizer production, and dead fish carcasses are used as raw material for liquid fertilizer production. The SFA (substance flow analysis) method was applied to evaluate the efficiency of nutrient source recovery in the system. The results show that the nutrient supply to fish ponds is mainly from fish food (about 30,450 kgN/ha/crop and 3,675 kgP/ha/crop). Harvested fish in the adult stage accumulate N and P content in fish biomass of 12,480 kgN ha/crop and 540 kgP/ha/crop respectively. Wastewater from fish ponds sent through aquatic ditches has an amount of 11,509 kgN/ha/crop and 2,978 kgP/ha/crop. The treatment efficiency of the aquatic pond reached 70%, and the amount of nutrients emitted into the environment through wastewater was 3,453 kgN/ha/crop and 893 kgP/ha/crop respectively. The efficiency of retaining nutrients after composting is about 70 - 80%, the product of this process is organic fertilizer containing N and P contents of 0.26% and 0.12% respectively.

   Published: 2023-12-31702-714
9. Original Research

   Fluctuations in rice yields and productivity in the comprehensive flood control dike area of the upstream VietNam Mekong Delta: A case study of An Giang province

   Tươi H.,ỳn., Quang C.,âu Thiện N.,ễn Dũng T.,ần Dương Vũ

   Full dyke system has greatly benefited farmers in cultivating triple rice cropping during flooding seasons in the Mekong Delta. Although tripple rice cropping brings benefits, its full dyke system has changed flooding situation in the Mekong Delta and stopped sediments to enrich the rice fields. Long-term intensive rice cultivation leads to soil degradation, which is one of the causes of reduced rice yields and productivity. The study aims to evaluate the changes in triple rice yield and productivity under the effect of a flood control dyke system in An Giang province. Spatial data on flooding and land use derived from MODIS satellite imagery was analyzed and compared with data of flood extension from Radar satellite product, while land use data from MODIS was verified with cultivation rice data from Statistical Yearbooks issued by An Giang province from 2000 - 2020. The result of this study shows that the flooded area decreased by 65.92%, creating conditions for farmers to expand the triple rice cropping area by 46,61%. However, the area of triple rice cropping in the phase of 2011 - 2020 has reduced 13.90%. As a result, the production decreased by 9.82% in the proportion of rice in the whole year and a 0,83 ton/ha decreased in comparison with the period when the dyke system was still under construction (2000-2011). In addition, triple rice cropping was practised in the protected flood control dyke systems in the upstream districts has higher average yields than those in the downstream districts (5.60 tons/ha compared to 5.40 tons/ha). The research shows a positive correlation between the increase in the area of flood control dyke system and the yield and production of triple rice cropping. The research results provide insights for researchers and policymakers in the region to adapt appropriate plans to minimize flood risks and ensure livelihood stability for farmers in the flood control dyke system in the upstream area, e.g. An Giang province, of the Mekong delta.

   Published: 2023-12-31786-802
10. Original Research

    Studying environment characteristics of cultivation land in Dai Thinh Area, Me Linh District, Ha Noi city to serve sustainable development of health safe vegetables

    Dang V., Nguyen G.

    Cultivation land (Planting Soil) is a natural resource that plays an important role for organisms and humans. Soil pollution will badly affect human and animal health through food, vegetables, fruits, medicinal herbs, etc. To clarify the characteristics of the geochemical environment and estimate the quality of the soil environment in the Dai Thinh area, Me Linh district, Hanoi city, the authors combined the using of traditional and modern methods in the research process, such as: field research methods, grain-size analytical method plus X-ray fluorescence spectroscopy (XRF) method to determine the major components (oxides) of soil. The high-frequency inductive plasma source spectroscopy combined mass spectrometry (ICP-MS) method and optical AAS atomic adsorption spectroscopy have been used to determine the concentration of critical heavy metals in soil samples. Besides, the direct measurement method used to determine environmental indicators (pH, Eh, Ec). Research results show that agricultural soil in the studied area belongs to the group of heavy sandy loam, sandy loam, and sandy clay soils, with average content of sand (size of 0.05-2mm): 60.8 (%), silt (limon) (size of 0.005-0.05mm): 17.96 (%), clay (size of <0.005mm): 21.46 (%). The soil has not been yet polluted by critical heavy metals such as: As, Cd, Cu, Zn, Cr, Ba, Sb, Co, Mo, Se and Sn. The soil in the studied area shows neutral acid-base values (average pH is 6.61), has a strong oxidizing environment (Eh > 150mV) (with values of Eh ranging from 183 to 310 mV), and is not saline (values of Ec ranging from 58.7 - 317.0 (µS/cm). Therefore, in terms of the results of determining environmental physical-chemical criteria and heavy metal concentration, the soil in the studied area can be used for health safe vegetable production. The research results not only serve as a basis for assessing the quality of the soil environment for safe healthy vegetable planting, but also serve as a scientific basis for the authors to propose a number of appropriate solutions to protect and improve the quality of vegetables, land environment protection, contributing to the planning and sustainable use of agricultural lands for the studied area.

    Published: 2023-12-31764-775