Evaluation of the efficiency of the liquid waste treatment system in coal mining at khanh hoa coal mine

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURAL AND FORESTRY NGUYEN THI HANG EVALUATION OF THE EFFICIENCY OF THE LIQUID WASTE TREATMENT SYSTEM IN COAL MINING AT KHANH HOA COAL MINE BACHELOR THESIS Study Mode: Full-time Major: Environmental science and management Faculty: International Programs Office Batch: 2015 - 2020 Thai Nguyen, 20/11/2020 DOCUMENTATION PAGE WITH ABSTRACT Thai Nguyen University of Agriculture and Forestry Bachelor of Environmental Science and Degree Program Management Student name NGUYEN THI HANG Student ID DTN1553050061 Evaluation of the efficiency of the liquid waste Thesis Title treatment system in coal mining at Khanh Hoa coal mine Supervisor (s) NGUYEN HUU THO, PhD Supervisor’s Signature Abstract: Coal mining is an activity that has been interested in investment and development for a long time Risk reduction measures in open coal mining are also calculated and given specific directions Inherently, coal mining activities here have brought many economic benefits, created jobs for local people, contributed to promoting the development of the market economy The water environment situation of Khanh Hoa coal mine is concerned and periodically checked The expansion and increase in capacity of coal mines in recent years have had a great impact on the water environment in the region, so the company has invested in the construction of wastewater treatment facilities to minimize environmental pollution Water is periodically monitored by environmental experts and relevant organizations, to ensure the quality of ii wastewater discharged into the environment, as well as to take measures to repair wastewater treatment systems in time to limit negative impacts to the environment Besides, the Company always strives to find more effective measures in environmental protection Therefore, the wastewater treatment efficiency is better, helping to reduce operating costs In recent years, Khanh Hoa Coal Company - VVMI has completed and put into use environmental protection works In addition, the Company regularly organizes activities to respond to environmental holidays, educates and propagates knowledge on environmental protection for employees throughout the Company to raise awareness of protection and hygiene environment Wastewater, water, wastewater treatment plant, Keywords: environmental, coal, domestic system Number of pages: 53 Pages Date of Submission: November 20, 2020 iii ACKNOWLEDGEMENT Over the internship at Khanh Hoa-VVMI Coal Company where it is very suitable for the environment industry Here, we have initially grasped: - Diagram of coal mining process; - Discharge from coal mining; - Methods of wastewater treatment during coal mining; During my internship, I have strictly follow all the rules of the company set out, try, actively study, grasp the labor safety process During my internship, I have strictly follow all the rules of the company set out, try, actively study, grasp the labor safety process With the knowledge learned on the school chair combined with practical observation, through this internship has helped me to add knowledge and learn experience working for myself With the knowledge learned on the school chair combined with practical observation, through this internship has helped me to add knowledge and learn experience working for myself In order to complete this internship report, in addition to my efforts, I would like to express my deep gratitude to: In order to complete this internship report, in addition to my efforts, I would like to express my deep gratitude to: - The teachers of the advanced program have dedicatedly taught in the past semesters, especially thanking the instructor Mr Nguyen Huu Tho for dedicatedly guiding me to complete this internship iv - The board of directors and employees of Khanh Hoa-VVMI Coal Company have dedicatedly guided and facilitated me to complete this internship Due to the short internship time, my ability is limited and initially approaching the reality is still very difficult, so I can not avoid mistakes, I look forward to receiving the sympathy and suggestions of teachers and friends Thank you very much! v TABLE OF CONTENT List of figures List of tables List of abbreviations PART I INTRODUCTION 1.1 Research rationale 1.2 Introduction of Khanh Hoa coal company- VVMI 1.2.1 Geographical location 1.2.2 Type of exploitation 1.2.3 Target 1.2.4 Organizational structure 1.2.5 Capacity and mine life 1.3 Research’s objectives 1.4 Research questions and hypotheses 1.4.1 Research questions 1.4.2 Hypotheses 1.5 Limitations 10 1.6 Definitions 10 PART II LITERATURE REVIEW 12 2.1 Current status of coal mining environment in Khanh Hoa coal company 12 2.1.1 Current status of Khanh Hoa coal mine in Thai Nguyen province 12 vi 2.1.2 The water environment situation due to the operation of the Khanh Hoa coal mine in the province 12 2.2 Measures to minimize water pollution 13 2.2.1 Measures for storm water runoff and construction wastewater 13 2.2.2 Measures for domestic wastewater treatment 15 2.3 Environmental monitoring, prevention and response measures 16 2.3.1 Legal records of environmental protection 16 2.3.2 Regarding the current state of the water environment 17 2.3.3 Water environmental protection works and measures 18 2.3.4 Works, measures to treat and minimize environmental impacts from other waste sources 19 2.4 Environmental monitoring and management program 21 PART III RESEARCH METHODS 25 3.1 Research time and scope 25 3.2 Research content 25 3.3 Research Methods 25 3.3.1 Collect key information Error! Bookmark not defined 3.3.2 Methods of collecting secondary information Error! Bookmark not defined 3.3.3 Analytical method Error! Bookmark not defined 3.3.4 Data processing method Error! Bookmark not defined PART IV RESULTS AND DISCUSSION 26 A - RESULTS Error! Bookmark not defined 4.1 Origin of coal mine wastewater 26 vii 4.2 Results of measuring and analyzing wastewater 27 4.2.1 Results of measuring and analyzing wastewater from mining pits the first phase in 2020 27 4.2.2 Results of measuring and analyzing groundwater phase I in 2020 29 4.2.3 Results of measuring and analyzing surface water phase I in 2020 30 4.2.4 Results of measuring and analyzing domestic wastewater phase I in 2020 32 4.3 Wastewater treatment technology 33 4.3.1 For mining pits wastewater 34 4.3.2 For ground water 42 4.4.3 For surface water 43 PART V: DISCUSSION AND CONCLUSION Error! Bookmark not defined 5.1 Discussion…………………………………………………… 46 5.1.1 General concept of coal mine wastewater 46 5.1.2 Water treatment 47 5.1.3 Preventing drifting and filling landfills, preventing sedimentation of rivers and streams……………………………………………………………….48 5.1.4 Dredging plan……………………………………………………… 48 5.2 Conclusions 499 REFERENCES 52 viii LIST OF FIGURES Figure 1.1: Khanh Hoa Coal company Figure 1.2: Topographic map of Khanh Hoa coal mine Figure 1.3: Open-pit mining At Khanh Hoa coal mine Figure 2.1 Design principles of drainage ditches and settling manholes 14 Figure 2.2: Current mine oil and grease treatment diagram of the mine 20 Figure 4.1: Wastewater treatment area at Khanh Hoa coal mine 34 Figure 4.2: Diagram of wastewater treatment process technology for Khanh Hoa coal mine (New investment in construction) 38 Figure 4.3 Pump system 39 Figure 4.4: Location of Wastewater through the mixing compartment PAC and PAM deposition aid 40 Figure 4.5 Exhaust door, installation of automatic monitoring system Flow monitoring parameters of TSS and iron 41 Figure 4.6: Sludge storage tank 42 Figure 4.7: Schematic structure of a sedimentation pit of overflow water collection system on the site 43 Figure 4.8: Structure of a 3-compartment septic tank 46 LIST OF TABLES Table 1.1: Current number of employees at the mine Table 4.1: The results of wastewater analysis from mining pits 27 Table 4.2: The results of wastewater analysis from groundwater 29 Table 4.3: The results of wastewater analysis from surface water 30 Table 4.4: Results of measuring and analyzing the quality of domestic wastewater 32 Figure 4.3 Pump system At the flocculation compartment, the flocculation solution and the PAC, PAM deposition aid are pumped into and mixed with wastewater by a stirrer, then water flows itself into the reaction compartment The powdered PAC and PAM deposition agent are prepared at the operator into a solution of 0.1% concentration The flocculation solution is pumped quantitatively from the preparation tank to the flocculation compartment First, add PAC to reduce viscosity, increase the absorption between small particles to form larger particles, then add PAM to increase convergence of particles when in contact with each other form a large flocculation, speed up deposition - The flocculation solution is mixed with wastewater by a stirrer installed in the flocculation compartment to have the effect of distributing, distributing upstream, swirling to speed up flocculation and deposition 39 Figure 4.4: Location of Wastewater through the mixing compartment PAC and PAM deposition aid At the reaction compartment, Wastewater through the mixing compartment PAC and PAM deposition aid, continues to be passed through the slow stirring compartment to help the flocculants and deposition aids disperse into the water and make the Small sized suspended solid particles stick together to form colloidal cotton - these colloidal flakes will settle by gravity, the faster and more efficiently they settle thanks to the sloped slabs due to the water from the reactor in the sedimentation tank, it will move from the bottom up according to the slanted slab of lamella in the process of moving the colloidal cotton will collide and stick to the surface of the lamenlla settling plate When the colloidal cotton sticks together on the surface of the lamella settling plate is heavy enough and can overcome the repulsion of moving water, the colloidal cotton will slide 40 down in the opposite direction and fall to the bottom of the settling tank After sedimentation, wastewater is taken to a tank containing clean water and discharged into the stream Sludge from regulating tanks to settling tanks is transported to sludge tanks and by sludge pumping system respectively Figure 4.5 Exhaust door, installation of automatic monitoring system Flow monitoring parameters of TSS and iron The sludge stored in the sludge tank is compressed naturally, then dumped by a dedicated sludge truck at the disposal site (sludge composition is mainly non-toxic inorganic substances) 41 Figure 4.6: Sludge storage tank The wastewater treatment station is controlled by a semi-automatic form 4.3.2 For ground water Groundwater in the project area exists and moves in the fracture zone of the sandstone and grit layers while the clay, coal clay and coal layers are the water insulation layers Groundwater is poor, the permeability coefficient K