Chronic effects of domestic and single used plastic leachates on the microcrustacea Daphnia magna

Plastic pollution has become one of the most serious environmental issues worldwide. Plastics can contain high amount of additives (e.g., phthalate, bisphenol A, trace metals), and they could be leached out of plastics, enter the aquatic environment and cause toxic effects to aquatic organisms (including microcrustacean). In this study, we investigated chronic effects of plastic leachates from two popular plastic materials (garbage bag and disposable raincoat) on the survival, maturation and reproduction of the microcrustcean Daphnia magna. The results showed that, the plastic leachates from the two materials at the concentration up to 1000 mg/l did not cause negative effect on survival of D. magna. However, exposed to the leachates from the garbage bag (at the concentrations of 10, 100 and 1000 mg/l) and from the disposable raincoat (at the concentration of 10 mg/l), the animals delayed their maturity ages compared to the control. Besides, the two kinds of leachates at the concentration of 1000 mg/l stimulated the reproduction of D. magna, resulting the increase of 17 – 37% of total offspring compared to the control, during 21 days of experiment. The results of this study contribute to the understanding on the toxicity of popular plastic materials to the microcrustacean, D. magna. Additionally, the plastic usage and emission into the environment should be paid more attention to protect the aquatic ecosystems and human health.

Evaluating the application ability of membrane-less microbial fuel cells in shrimp farming wastewater recirculation

Microbial fuel cell (MFC) was considerable as a promising saline wastewater treatment which using microorganism to convert organic compounds to electrical energy. Most of wastewater generated from aquaculture farming contained highly saline effluents. In addition, the maintenance of good water quality was essential for optimum growth and survival of shrimp. This study aimed to evaluate the ability of Membrane-less Microbial Fuel Cells (MFCs) to treat wastewater for recirculation of shrimp culture wastewater, and improvement in the growth performance of Penaeus vannamei (White Leg Shrimp). Six MFCs models were built with locally available materials such as: polyvinyl chloride (PVC), anaerobic sludge, carbon cloth anode and cathode electrodes, granular graphite, glass wool and glass bead. This study compared two different treatments including: control (cultivation with no MFCs models) and MFCs models (application models with shrimp culture), run in continuous mode at room temperature (250C – 30oC). Each treatment was run in triplicate with shrimp at size PL30-PL45, average initial weight of 0.91 +/- 0 (g) and average initial length of 3.03 +/- 0.6 (cm). Experiments were set up using the 120 L tanks (working volume of 90 L), input with seawater at 20 ppt salinity, temperatures range of 22◦C to 26◦C, pH range of 7.5 to 9.4, and dissolve oxygen range of 5.5 to 7.2. The density of shrimp was 5 post larvae (PL) per liter. Research results achieved the removal of chemical oxygen demand, ammonia, nitrite and nitrate were up to 58.83%, 76.1%, 56.33% and 70.90%, respectively. The survival rate of shrimp was maintained, and growth rate was enhanced significantly compared with control treatment. The obtained results in this study presented that MFCs has ability to treat pre-circulation of shrimp culture wastewater and improved in the growth performance of Penaeus vannamei (White Leg Shrimp).

Study of odor simulation and proposed odor isolation distance for some main pollutants (H2S, NH3, CH3SH ) for livestock activities: Applied in Ho Chi Minh City

Ho Chi Minh City (HCMC) is the largest city in Vietnam, with the highest economic growth rate and the most populous density in the country. By the year 2019, HCMC currently has 8.99 million people with 24 districts. Ho Chi Minh city has robust industrial and service development; therefore, HCMC focuses on developing large-scale livestock facilities with a large number of pigs and limiting small livestock facilities. According to statistic data, HCMC has a total of 290.152 pigs in 2018. These livestock facilities are mainly built in Cu Chi, Hoc Mon, Binh Chanh, Can Gio, and Nha Be districts. These livestock facilities in HCMC have inefficient waste treatment systems located interleaved with residential areas. So that, environmental issues are also a big challenge for the city's government because of the great influence of odor on the surrounding environment causing by the wind direction. The main purposes of this study are (i) calculation of odor emissions from livestock facilities, (ii) simulation of the odor from livestock facilities , and (iii) development of the safe distance of odor for livestock facilities in HCMC. The study results show that, the concertrations from livestock facilitties with capacity from from 50 to 200 pigs and 200 to 500 pigs are lower than QCVN 06:2009/BTNMT. The minimum distance for the livestock facility with capacity from over 500 to 1,000 pigs and over 1,000 pigs to the residential area are 230m and 650m, respectively. The procedure for calculating the odor isolation distance developing in this study could apply for other livestock facilities in other provinces, cities.

Study on the ability to remove Cd2+ ions in water environment by using halloysite mixture from Thach Khoan area, Phu Tho

Thach Khoan, Phu Tho area is the area with great potential for weathered kaolinite source from pegmatites of the Tan Phuong complex. This kaolin has quite good quality and is used in many traditional applications such as high quality ceramic glaze, high-grade bricks. However, the use of this material in the treatment of water pollution is still limited. In this study, the natural kaolin material from Thach Khoan area, Phu Tho province with about 87% amount of tubular halloysites was used to remove Cd2+ ion from water. The factors of pH, contact time, the adsorbent weight, and initial concentration of Cd2+ were studied to access their effects on the Cd2+ ion adsorption process using this raw material. The results indicated that under the conditions of pH0 of 6.5 and at room temperature (25 oC), with 0.8 g of halloysite powder and Cd2+ initial concentration of 30 mg/L, the adsorption of Cd2+ could reach equilibrium after 50 minutes with an efficiency of 86.31%. The adsorption process follows the Langmuir adsorption isotherm model with the maximum monolayer adsorption capacity of 2.75 mg/g and follows the second-order pseudo-adsorption kinetic equation. The results show that the natural halloysite material without treatment has the potential in using to remove heavy metal ions in polluted water and needs to be studied further.

An application of the multi-physical method of determining error of WRF models to simulate the track and intensity Usagi storm in 2018

This paper presents the test results of the WRF model error determination methods simulating the trajectory and intensity of storm Usagi in 2018. The study conducted three experiments: (1) The Combination of 11 options physical model, 21 composites, no increase in error correlation (MP); (2) Using a set of physical model, 21 composite components, multiplier growth factor l = 6.5 (MI); (3) Using a set of physical model, 21 compositions, no increase in error correlation (PF). Test results show that the multi-physics (MP) method has quite well simulated the intensity as well as the moving direction of the northern cold high pressure in the active Usagi storm area. As a result, The 2018 - Usagi 's trajectory and intensity is simulated in MP test better than in MI test and PF test. Specifically, at the 48-hour forecast term, the orbital prediction error of the MP test is below 350 km which is lower than the two tests (MI and PF), The orbital error in the MP test at the forecast term of 60 and 72 hours is 3-6% reduction in compared with the PF test, and in compared with the MI test, the orbital predictive error of the MP test decreased from 5% to 10% at the 12 hour to 72 hours forecast period. In terms of intensity, absolute error of Pmin (Vmax) in MP test always has lower value than two MI and PF tests. In particular, the absolute error of Vmax in the MP test decreased from 30-40% in compared to the other two trials at all forecasting terms, especially at the forecast term longer than 2 days. Thus, the multi-physics method can be a potential application of determining the error for the model to simulate the trajectory and intensity of storms affecting Vietnam.

Industrial - agricultural symbiosis model for cassava starch production factory in Tay Ninh province

This study aims to propose an industrial-agricultural symbiosis model that applies the closed sloop eco-technical solutions for cassava starch production towards sustainable development. This study applies the AHP method to analyze nine alternatives and determines the best one based on 17 specific criteria for the typical cassava starch production plant in Tay Ninh province. The chosen model has 12 losed sloop solutions and can save about 40% groundwater, hundreds of cubic metre of water for irrigation in agriculture (to meet hundreds of hectares of crops), limit the lack of water in the dry season and water regulation from the Dau Tieng lake and reduce from 19-73% emissions from traffic,... Wastewater after Biogas is diluted in proportion for cassava is 28l wastewater/49l of clean water and the rubber tree is 8,5l of wastewater/7l of clean water and sugar-apple is 20l wastewater/20l of clean water wasto spray as a natural leaf fertilizer, limiting the use of NPK chemical fertilizers. Some indicators of wastewater after treatment show that it is suitable for use as fertilizer but suitable for nutrient development in the soil and increase nitrogen for plant development, reducing the cost of using stimulating fertilizers. In addition, production wastewater with high cyanide levels is also considered to dilute according to certain proportions as natural insecticidal drugs. These results show that industrial-agricultural symbiosis model bring great enviromental benifits for cassava starch industry and can be replicated in the future.

THE The proposed integrated model for rural people of alum in the Mekong delta

This study is to design an integrated eco-agricultural system for waste treatment in the acidic soil areas in the Mekong Delta. The system is based on recycling all of the materials (from the inputs, outputs, and wastes) under conditions of acidic soil towards zero emissions and maintaining sustainability for farmers' livelihood. The system is demonstrated at Vo Van Tham's farm in Thanh An Commune, Thanh Hoa District, Long An Province. The cost investment is 80,000,000 VND, and the cost is 60,000,000 VND for operating per year. The results show that the proposed system has benefits for the environment, for example wastewater is collected and treated at is178 m3/day, reduce the emission of 756 tons CO2t/year. 50% the amount of pig manure (about 3 tons/day) is separated from pig shed discharges entering the biogas system. It also helps to increase household income (the expected income is about 160,000,000 VND/year, and the payback period is less than 1 year). In addition, solutions are used for alleviating soil acidity level, increase soil pH, and reducing aluminum toxicity in the area. This can help utilize difficult conditions of the acidic soil. Therefore, the proposed system can be applied widely for surrounding areas with similar livelihood activities, and natural conditions.

Reuse shrimp pond sedimentation to produce organic fertilizer in industrial scale

The purpose of this study is to reuse shrimp pond bottom sludge for industrial-scale organic fertilizer production, to reduce emissions from shrimp farming, and protect the environment. Sludge from the bottom of shrimp ponds is collected through channel settling with a filter net of 0.25 millimeters in size, rainwater is used to wash the salt content in the sludge of shrimp ponds. When the EC (Electrical Conductivity) of the sludge drops below 4 mS / cm, the sludge is mixed with dry straw at the rate of 1 ton of sludge with 250 kg of straw. The products of this rice straw and sludge mixing process are bio-fermented in two phases including anaerobic phase and aerobic phase. The results showed that the sludge-based fertilizers meet national technical regulation QCVN 01- 189: 2019/BNNPTNT. Of quality parameters, total organic carbon, macronutrients (N, P2O5, K2O), trace metals (Zn, Cu), and other heavy metals (Pb, Cd) are within the regulation limits. The paper also shows the potential of reusing shrimp pond bottom sludge for industrial-scale organic fertilizer production, with the possibility of utilizing nutrients contained in the sludge supplied to crops, especially reducing environmental pollution from intensive shrimp farming.

Evaluation for the vulnerability of climate change affecting to shark catfish farming in An Giang and suggesting some solutions for this case

Aquaculture - belonging to the Fisheries group - is one of the high-value economic sectors, accounting for a large part in the structure of the agriculture, forestry and fishery industry in Vietnam. However, the sustainability of this industry is facing many challenges due to climate change process; An Giang is a province that has long had a strong position in aquaculture in Vietnam and is not out of that influence. Therefore, there is an urgent need to assess climate change vulnerability of aquaculture in An Giang based on the predicted changes in temperature and rainfall of the region according to the change scenarios. climate. Unlike previous studies conducted mainly on a national scale, this paper is mainly concerned with Pangasius (Pangasius is one of the aquatic species with high commercial value, with significant contribution). including livelihoods of people in An Giang province) - species raised in the main production areas of An Giang and assess their vulnerability for each area, using an index-based method and Intergovernmental Panel on Climate Change Definition of Vulnerability to overcome constraints in developing specific adaptation strategies at regional scale. First, for each exposure, sensitivity and adaptability, specific and appropriate indicators are chosen. These indicators are then estimated and weighted to analyze vulnerability to climate change. The results show that the level of vulnerability due to climate change to the pangasius farming industry in An Giang province is at a moderate level, of which Chau Phu district is highly vulnerable because the district has the main livelihood of Pangasius farming.

Researching carbon varieties from season-caused shell for use of H2O2 properties to treat lead

The study assumes lead wastewater treatment with initial concentration fixed at 30 ppm and research material, denatured coal prepared from macadamia seed shell activated by heating, and finally variable Coal calculation with H2O2 agent. The coal was modified by soaking coal in 25% H2O2 solution for 48 hours. Coal after denatured for adsorption results reached 266.26 mg/g, the research results show similarities with some previous studies. On the other hand, when analyzing the infrared spectrum of coal, the FT-IR spectroscopic results showed that after denatured coal, there were some functional groups such as OH-, C-O, C=O, C-N, functional groups capable of participating in the adsorption of heavy metals in wastewater. When observing the SEM image, the photo results of the material show that the surface of the material is rough, with many pores and different sizes evenly distributed on the surface. From SEM image results and FT-IR spectroscopy results show that the material has the ability to adsorb heavy metals by many physical and chemical mechanisms. Indeed, when researching the application of materials to the treatment of lead heavy metals in presumptive wastewater, the research results show that lead treatment efficiency reaches 94.05% when surveyed at the same optimal conditions at pH = 6 with dose of 0.4 g/L and duration of 60 minutes. The control shows that the study results are similar to some previous research results, from which it can be confirmed that the modified coal material is capable of Pb (II) treatment in wastewater.