National Technical Regulation Research Articles

Evaluation of Mass Concentration and Size Distribution of Fine Particles (PM2.5) in Bien Hoa City, Dong Nai Province

Air pollution is one of the most concerning environmental issues, in which fine inhalable particles (PM2.5, with diameters that are generally 2.5 micrometers and smaller) concentration plays a key part. Bien Hoa city contains and locates close to several large industrial zones that might create sources of PM2.5 polluting the local air quality. This study monitors and evaluates PM2.5 concentration trends in Bien Hoa airport of Dong Nai province. PM samples are analyzed by Scanning Electron Microscopy (SEM) to recognize the surface pattern and size distributions are analyzed by ImageJ software. Ten samples of PM2.5 were obtained from sampling collected in October 2021. The results show that 24-h PM2.5 mass concentrations were from 15.2 µg/m3 - 50.4 µg/m3 with an average of 28.2 µg/m3; median of 24.1 µg/m3; and standard deviation of 12.2 µg/m3. The values are lower than the Vietnam National Technical Regulation on Ambient Air Quality (QCVN 05:2013/BTNMT) but far higher than the recommended values of the World Health Organization (WHO). SEM and image results indicate the distributions of the particles of 2.0 - 2.5 µm are minor, where the majority are particles with aerodynamic diameter ≤ 1.0 µm.
 Keywords: Air pollution; Fine particulate matters; PM2.5; Size distribution, Bien Hoa, Dong Nai.

The Categorized of Surface Water Quality Variation using Multivariate Statistical Approaches: A Case Study of Ben Tre Province, Vietnam

This study evaluated surface water quality changes in Ben Tre province using multivariate statistical analyses. The water monitoring data were collected from the Department of Natural Resources and Environment of Ben Tre province in 2020, which 13 water parameters have been measured, including pH, water temperature (T), salinity (Sal), turbidity (Turb), total suspended solids (TSS), dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonium (NH4+_N), nitrate (NO3-_N), orthophosphate (PO43-_P), iron (Fe) and coliform bacteria. Water quality was assessed using national technical regulations on surface water quality of QCVN 08-MT: 2015/BTNMT. Spatiotemporal variation of water quality was evaluated using cluster analysis (CA) while potential pollution sources and key water variables influencing water quality were evaluated using principal component analysis (PCA). The findings showed that the water parameters of turbidity, salinity, TSS, DO, BOD, COD, NH4+_N, PO43-_P, Fe and coliform exceeded the allowable limits of QCVN 08-MT:2015/BTNMT. The water parameters of BOD, COD, NO3-_N, PO43-_P in the rainy season tended to be higher than those in the dry season. Cluster analysis divided surface water quality into 7 clusters, thus reducing 8 sampling sites, and 2 monitoring times of frequency. Principal component analysis identified 13 potential pollution sources affecting surface water quality in the study area, in which, 76.10 % of the variation in surface water quality were contributed by PC1, PC2, PC3, PC4 and PC5. PCA results also showed that 13 observed water parameters significantly contribute to the variation in water quality. The current study results could be very useful in reducing sites and frequency of surface water quality monitoring in Ben Tre province. HIGHLIGHTS The water quality in the study area was polluted by suspended particulate matters, organics, nutrients, heavy metals and salinity. Thirteen potential water pollution sources have been identified by principal component ananlysis (PCA), in which, 76.1 % of surface water quality variations were explained by five key sources sources of PC1-PC5 The water quality parameters of BOD, COD, NO3-_N, PO43-_P in the rainy season tended to be higher than those in the dry season Cluster analysis (CA) suggested the current surface water monitoring sites and frequency of the sampling could be reduced by 8 and 2, respectively, thus, saving the monitoring cost GRAPHICAL ABSTRACT

Assessment of surface water quality and monitoring in southern Vietnam using multicriteria statistical approaches

The study was conducted to analyze surface water quality fluctuations in the the southern region of Vietnam using monitoring data at 58 locations. Seventeen water quality indicators were analyzed including pH, temperature, electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS), total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD), ammoniacal nitrogen (NH4+- N), nitrite nitrogen (NO2−-N), nitrate nitrogen, iron (Fe), lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), and chloride (Cl− ions). The study used water quality index (WQI), cluster analysis (CA), principal component analysis (PCA), and Entropy weighted methods to analyze surface water quality. The results showed that the surface water was contaminated with organics (low DO and high TSS, BOD, COD), nutrients (high NH4+-N) and Fe. While Pb at some locations exceeded the allowable limit of the national technical regulation, other indicators (Cd, Hg and As) were within this standard. Moreover, DO, TSS, BOD, COD, NH4+-N, Fe, EC, TDS, and Cl− were seasonally fluctuated. WQI classified water quality from bad to very good (WQI = 42–100) due to the impact of hydrological conditions, navigation, wastewater from industrial zones, and fishing ports. The results of CA suggested that it is possible to reduce the 11 sampling locations (from 33 to 22 locations) in clusters 1–6 and the frequency of monitoring from 8 to 5 times per year, which still ensures representativeness of water quality over time. This reduction allows lowering the monitoring costs by 56.5%. The PCA identified five major potential sources explaining 87.3% and 8 minor sources explaining only 12.7% of water quality variation. Temperature, pH, EC, DO, BOD, COD, NH4+-N, NO2−-N, Fe, Cl−, Pb are important indicators need to periodically be monitored. Furthermore, orthophosphate, total phosphate, total nitrogen, coliforms should be considered to add into the next monitoring program. Locations with medium and bad water quality are concentrated in Dong Nai, Ho Chi Minh City and Long An, which requires finding effective solutions to improve the water quality. The current results can assist in decision-making related to environmental quality monitoring in the southern region of Vietnam.

Research on the chemical compositionof water resources for gene conservationand development of H’mong cattle value chain in the northern mountainous region

The science and technology project “Application of technology to develop high-quality beef cattle into goods according to the value chain in the northern mountainous region” (hereinafter referred to as the H’mong cattle project) is implemented under Decision No. 1754/2018/QD-BKHCN dated June 25, 2018, of the Minister of Science and Technology. This is a national science and technology project implementing the application of new technologies to develop products according to the quality beef value chain in the northern mountainous provinces. The project is located at Dong Luong village, Quang Chu commune, Cho Moi district, Bac Kan province, that is oriented to develop a nuclear cow herd that preserves the H’mong gene. In cow breeding, water source plays a very important role in the growth and development of cows. In the project area, water for domestic use is often taken from wells or surface water from ravines, which have high hardness and heavy metals pollution, NO2- or E. coli. In order to ensure water quality for the Centre for Genetic Conservation and Development of H’mong cattle, for raising original H’mong cows, the authors have conducted experiments to study heavy metal content in the surface water samples (from rock ravines) and groundwater samples (fromdrilled wells). Water samples were taken at different times of the year and analysed by modern equipment with high sensitivity, high accuracy, and detection limit to ppt (ng/l). Measured results are compared with the QCVN 01-1:2018/BYT National Technical Regulation on Domestic Water Quality issued by the Ministry of Health.

Risk associated with occurrence of toxic elements in the environment surrounding landfills in An Giang Province, Vietnam

The study aimed to evaluate the concentration of potentially toxic elements in the soil samples of landfill sites in An Giang province. Eighty-eight soil samples were collected from five landfills. The potentially toxic elements including Cu, Zn, Pb, Cd, and As were analysed and compared with the National technical regulations on the allowable limits of heavy metals in the soils. A cluster analysis was applied to identify the sampling sites with similar soil toxic elements properties. The ecological potential risk index was used to determine the risk of the landfills to the ecosystem. The results showed that four out of five potentially toxic elements were detected in the soil, and their concentration decreased in the order of Zn > Cu > Pb > As. Most of the potentially toxic element concentrations were within the allowable limits, except for Cu and As in some positions. The ecological potential risk index in unsanitary landfills was higher than that in a sanitary landfill; however, the level of risk was low. The occurrence of toxic elements in the soil around the landfills affects the ecosystems as well as human health. Therefore, it is necessary to prevent the effect of heavy metals in the surrounding environments.

Regulations for Protecting Workers in Industrial Clusters – and Food Safety Protection

This paper aims to focuses on studying current situation of food safety and Related Regulations for protecting workers in industrial clusters- And Food Safety Protection. By using description, qualitative analysis including synthesis and inductive methods, This study finds out that according to regulations, The Minister of Health, the Minister of Agriculture and Rural Development, and the Minister of Industry and Trade shall promulgate national technical regulations and specific regulations on conditions for ensuring food safety for production establishments, produce and trade in food in the areas it is assigned to manage.

Studying the biochar modified by AgNO3 from coffee grounds to handle organic pollutants and microorganism in the seafood-processing wastewater

The aim of this study is to use four types of biochar modified AgNO3 from coffee grounds including CF5 (600°C/1.5h), CF6 (600°C/3h), CF7 (700°C/1.5h), and CF8 (700°C/3h) for the treatment of organic contaminants and microorganism in the seafood-processing wastewater. The results showed that the materials had the porous structure and the diameter of the pores corresponded to the crystal plane. The carbon content in the four samples reached over 90%. In addition, four samples observed the presence of Ag with the weight percentage varying from 0.06 to 0.09%. The adsorption capacities for pollutants by the four materials at different times were different. After the adsorption time, the COD value was still from 1.6 to 5.2 times higher than the limited value of the Vietnamese Standard QCVN 11:2015/MONRE - National technical regulation on the effluent of aquatic products processing industry. The three remaining parameters: TSS, ammonium (NH4+), and microorganism met the standard limit value requirement of QCVN 11:2015. The TSS contents decreased with the lowest adsorption efficiency in CF5 sample (68.87%) and the highest value in CF8 sample (99.21%); NH4+ content decreased respectively from 385.14 mg/L to 19.97; 15.55; 21.5 and 19.16 mg/L (CF5-CF8) with the efficiency over 94% after 2h adsorption. The removal capacity of coliform in CF7 sample is the highest value of 640 MPN/100 mL with the efficiency of 98.61% while the lowest one obtained in CF5 sample with 4.300 MPN/100 mL and the efficiency of 90.65%.

Information Security of Ukraine in the Context of National Security

The article considers issues related to the study of modern views and features of the regulatory framework of information security of Ukraine in the context of information security. It is noted that the current actions of the Russian Federation aimed at violating the territorial integrity, destabilization of the situation in Ukraine, which are implemented, including due to the destructive information impact have become a serious challenge for our state. According to the results of the analysis, it is determined that the security of any country comprehensively embodies all important areas of life and development of man, society and the state. Its components are informational, intellectual, political, military, economic, environmental and other factors. The place and role, as well as the priority of each of them are determined by the circumstances that actually develop over a period of time within and around the state. It is proposed to improve the legal and institutional arrangements for the management of State security by: – further development of national security legislation; – development and implementation of national standards and technical regulations for the use of information and communication technologies, harmonized with relevant European standards; – introduction of a nationwide system for determining and monitoring the level of protection of national interests in various spheres of life and taking into account real and potential threats to the information security of the state; – intellectual and personnel and resource support; – bringing legislation on the protection of various types of information with limited access to European standards, etc.

Structural analysis of catamaran sailing yacht

In terms of structural design, the analysis of catamaran hull ships in general and catamaran hull sailing yachts in particular is always interested, especially the cross structure and the connection of the two hulls with the cross structure. The application of the hull structure analysis technique by the finite element method is said to be the most feasible in the current period. With the small vessel size, the analytical model can be run on personal computers (PC) to ensure the reliability of the calculation results in ANSYS WORKBENCH. This paper focuses on analyzing the structure of catamaran hulls and the cross structure on the basis of the guidelines of the DnV-GL Register and the load condition in accordance with the National Technical Regulation on Rules of Inland - waterway Ship Classification and Construction 2nd Amendment: 2018 QCVN 72/2013 BGTVT. The obtained results help the structural designer to make a reasonable selection of the overall shape as well as the local connections for the catamaran sailing yachts.

A Small-Scale Study on Removal of Heavy Metals from Contaminated Water Using Water Hyacinth

The aim of this research was to determine whether water hyacinth can be used to remove heavy metals, such as cadmium, arsenic, lead, zinc, and copper, from industrial wastewater. Investigations of the pollution removal or prevention potential of aquatic macrophytes, such as heavy metal bio-indicators in aquatic habitats, can prove to be advanced field studies. Water hyacinth is one of the aquatic plant species that has been effectively utilized for the treatment of wastewater. It is extremely effective in removing stains, suspended solids, BOD, organic matter, and heavy metals. This research focused on the use of water hyacinth to treat wastewater from heavy metals. Water hyacinths can grow in sewage, absorbing and digesting contaminants and transforming sewage effluents into comparatively clean water in the process. As a result, the plants have the potential to be used as natural water purification systems at a fraction of the cost of a standard sewage treatment facility. The experiment was performed using healthy, young, and acclimatized water hyacinths. Containment water with a cadmium concentration of 0.5 mg/L, arsenic concentration of 0.5 mg/L, lead concentration of 2 mg/L, zinc concentration of 5 mg/L, and copper concentration of 5 mg/L was added to five different polyethylene pots with 100 g of water hyacinth in each pot. After 30 days, the removal efficiency for heavy metals (Cd, As, Pb, Zn, and Cu) reached 59–92%, and the results were within the permitted limits according to the National Technical Regulation on Industrial Wastewater in Vietnam. Based on this information, it is possible to deduce that water hyacinth can be utilized to remove cadmium, arsenic, lead, zinc, and copper from industrial wastewater effluents efficiently.

First evaluation of iron and manganese concentrations in coastal aquaculture water in Giao Thuy district, Nam Dinh province

Aquaculture in the coastal zone has contributed significantly to economic development in Giao Thuy district, Nam Dinh province. Therefore, water quality for aquaculture plays a vital role in sustainable aquaculture production. In this paper, iron (Fe) and manganese (Mn) concentrations in aquaculture coastal water of Giao Thuy district were analyzed during the rainy season (September 2017, August 2018) and dry season at low tide. The results showed that Fe concentration varied from 0.09 mg/L (at VT5) to 2.42 mg/L (at VT4), averaging 1.12 ± 0.71 mg/L, which exceeded the critical value of the national technical regulation on marine water quality in Vietnam for coastal aquaculture water (QCVN 10:2015/BTNMT) from 1.5 times (at VT4) to 3.0 times (at VT1). Mn concentrations ranged from 0.02 mg/L (at VT9) to 0.10 mg/L (at VT1), averaging 0.05 ± 0.02 mg/L, which was lower than the critical value in the QCVN 10:2015/BTNMT. The results showed that no apparent seasonal variation was observed for both Fe and Mn concentrations. In the dry season, the Fe and Mn concentrations averaged 1.10 mg/L and 0.05 mg/L respectively, whereas they were 1.15 mg/L and 0.05 mg/L in the rainy season. The monitoring results showed that Fe was polluted in the study area and may affect aquaculture productivity. Therefore, helpful measures should be taken to minimize Fe pollution to protect water quality and develop sustainable aquaculture in Giao Thuy district, Nam Dinh province.

Control of textile wastewater by electron beam irradiation in combination with biological treatment

Environmental pollution, especially water pollution, is of great concern nowadays. Textile wastewater treatment by electron beam irradiation (EB) shows the advantage of not using toxic additives and not creating secondary sludge. In this study, textile wastewater was treated by electron beam irradiation in a low absorbed dose range of 0.5-2 kGy in combination with biological treatment. Besides, a study on combining EB irradiation and H2O2 oxidizing agent was also carried out to reduce the absorbed dose. The results show that after EB irradiation in the presence of oxidizing agents H2O2 combined with biological treatment, the color indicator of wastewater is within the allowed range according to column B of the national technical regulation on the effluent of the textile industry (QCVN 13–MT/2015/BTNMT), which is eligible for discharge into the environment. Research on the treatment of textile wastewater by EB irradiation combined with biological methods has shown that it increases the ability to effectively treat textile wastewater, contributing to reducing the environmental pollution.

Development of new homogeneous photo-Fentoncatalytic systems using oxalic acid and ferric ions in very low concentrations

In this work, we proposed to combine oxalic acid and ferric ions in very low concentrations to create new, economic, and effective homogeneous photo-Fenton catalytic systems for the degradation of methylene blue. The effects of ferric concentration, H2C2O4 concentration, pH, and tert-butanol on the catalytic activity were also investigated. According to the experimental results, Fe3+ ions exhibited impressive catalytic performances in the presence of H2C2O4 at concentrations below type B (5.0 mg.l–1) from the Vietnam National Technical Regulation on Industrial Wastewater. Specifically, a ferric concentration of 3.0 mg.l–1, H2C2O4 concentration of 10–3 mol.l–1, and pH value of 3 were found to be the best conditions for MB degradation under UVA light. Furthermore, owing to a very low concentration of ferric ions, iron sludge formation can be avoided after wastewater treatment, which makes the photo-Fenton process suitable for practical applications.

Design and analysis of a Cross Car frame. Proposal of a three-level appraisal methodology

This paper analyses the structural design process of a Cross Car frame. Existing international and national technical regulations were analysed. The analysis of the regulatory guidelines led to the conclusion that the design only includes geometric or material restrictions at the international level. There are other more demanding national regulations (Spanish, for instance) that include structural verifications through static calculations for unidirectional actions (vertical, longitudinal or lateral). The main contribution of this paper is a novel three-level appraisal and a proposed redesign methodology. At the first level, a geometric and material verification is carried out. The second level involves the verification under unidirectional static actions. The third level entails a dynamic verification of three-dimensional combined actions. The load case is obtained from the computer multibody dynamics simulation of the full vehicle assembly in the worst case of driving conditions on circuits. This methodology is a far more detailed tool than traditional design processes. The use of this methodology allows for design optimisation, including all the effects of powertrain, brakes, suspension, steering and driver.

Criteria of medical response to radiological emergencies in the Republic of Belarus

The Republican Research Center for Radiation Medicine and Human Ecology in the Internal and External Emergency Plans of the Belarusian nuclear power plant is specified as an institution that provides specialized treatment for personnel, as well as persons from the population living in the emergency zone of the station. The plant is the first facility in the Republic that used nuclear energy. There is no experience in treating radiation injuries in Belarus. This is the first time that the National Health Service has been assigned the task of ensuring readiness for the reception and specialized treatment of people who have been exposed to emergency or unplanned radiation. The purpose of the work is to establish criteria for radiation exposure for use in a Belarusian specialized medical institution in case of medical response to radiological accidents. As a result of the analysis of publications of international organizations, the criteria of radiation exposure that can be applied in the conditions of Belarusian specialized medical institutions were selected. Assessment of the criteria was made taking into account existing national technical regulations and the available capabilities of emergency response participants. To account for the quality of radiation in relation to deterministic effects “Gy-equivalent” is used. The criteria include both dosimetric values for cases of external and internal accidental and unplanned exposure, and levels of radioactive substances with unknown physical and chemical properties entering the body that require urgent medical intervention. Criteria for cases of surface contamination of skin and wounds require separate consideration.

Factors Affecting Slope Instability of the Nhan Co Alumina Red Mud Basin and Economical, Environmentally Friendly Soil Stabilization

Since 2017, there have been recurring landslides in the red mud basins of the Nhan Co alumina factory, Dak Nong Province, Vietnam, during the rainy seasons. Changes in physical and mechanical soil parameters due to rain water infiltration and the formation of tension cracks have been considered as the main causes of slope instability. The soil cohesion and angle of internal friction decreased nearly thrice and twice, respectively, as the soil became saturated. An economical and environmentally friendly reinforcement using bamboo stem piles in combination with slope regrading is suitable for the site conditions. With a light slope regrading, a bamboo stem pile spacing of 5.3 m ensures that the slope factor of safety (FS) is 1.30, which satisfies the requirements specified by the national technical regulations. The results are helpful and serve as practical fundamentals for a comprehensive control of slope stability of the red mud basins in the Nhan Co alumina factory to avoid possible catastrophic destruction of the local ecology by the spreading of an extremely high pH fluid and mud from the red mud basins due to the landslides into the red mud basins.

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.

Nghiên cứu mô hình xử lý nước suối Tà Vải tỉnh Hà Giang bằng công nghệ màng lọc kết hợp vật liệu lọc đa năng để cấp nước phục vụ cho sinh hoạt

Clean water is a basic necessity for daily life. Clean water helps people maintain their daily lives in case of domestic activities. If using unclean water, it will be harmful to the health because water is the medium that transports chemicals and bacteria, viruses, parasites causing diseases that are not visible to the naked eyes. According to statistics, Our country still has many places where the quality of water supply is not ensured for daily life, especially in mountainous, frontier areas and places where the terrain is difficult and lacks of facilities. The water used for living in the northwestern region in general and the Ta Vai stream’s basin in Ha Giang province in particular is taken from rivers and streams that have not been treated or have been processed but the water quality is not guaranteed for living. Therefore, a study on the construction of the treatment model of Ta Vai spring water in Ha Giang province by using membrane technology combined with integrated filter materials for water supply is essential. The research shows that the water treatment model in Ta Vai stream by using membrane technology combined with integrated filter materials has completely treated water as reaching the quality of QCVN 02: 2009 / BYT - National technical regulation on domestic water quality.

EVALUATING SURFACE WATER QUALITY AND WATER MONITORING PARAMETERS IN THE TIEN RIVER, VIETNAMESE MEKONG DELTA

The study aimed to evaluate the surface water quality of the Tien River and identify water quality parameters to be monitored using the water quality monitoring data in the period of 2011 - 2019. The water samples were collected at five locations from Tan Chau to Cho Moi districts, An Giang province for three times per year (i.e., in March, June, and September). Water quality parameters included temperature (oC), pH, dissolved oxygen (DO), total suspended solids (TSS), nitrate (NO3--N), orthophosphate (PO43--P), biological oxygen demand (BOD), and coliforms. These parameter results were compared with the national technical regulation on surface water quality QCVN 08-MT: 2015/BTNMT, column A1. Principal component analysis (PCA) was used to identify the sources of pollution and the main factors affecting water quality. The results of this study showed that DO concentration was lower and TSS, BOD, PO43--P, coliforms concentrations in the Tien river exceeded QCVN 08-MT: 2015/BTNMT, column A1. pH, temperature, and NO3--N values were in accordance with the permitted regulation. The water monitoring parameters were seasonally fluctuated. DO, BOD, TSS, and coliforms concentrations were higher in the rainy season whereas NO3--N and PO43--P were higher in the dry season. The PCA results illustrated that pH, TSS, DO, BOD, PO43--P and coliforms should be included in the monitoring program. Other indicators such as temperature and NO3--N could be considered excluded from the program to save costs.

Surveying causes of surface water pollution at Sao River, Binh Thuy district, Can Tho city, Vietnam

Surface water sources play an important role in human and biological activities and the socio-economic development of the region. Therefore, the assessment of water quality and determination of the causes of water pollution in Sao river is essential for good management of the surface water environment. The study was conducted from July to December 2020. Water samples were collected at the time of low tide to evaluate the water quality indicators of temperature, pH, conductivity (EC), dissolved oxygen (DO), biological oxygen demand (BOD), total suspended solids (TSS), ammonium (N-NH4+), orthophosphate (P-PO43-) and coliform. The source of pollution was determined by direct interviews with households living near Sao river. The results showed that surface water quality in Sao river had signs of organic pollution and microbiological pollution due to BOD, TSS, N-NH4+, P-PO43-, coliform exceeded the allowable limits of National Technical regulation on surface water quality (QCVN 08-MT:2015/BTNMT, column A1). The results of the interview revealed that 70% of respondents said that water was seriously polluted and the main sources of pollution were domestic solid waste and domestic wastewater. Therefore, to improve surface water quality in Sao river, solid waste and wastewater management is urgently required. It is necessary to promote the monitoring and management of water quality with the participation of local authorities and communities.