TÓM TẮT KẾT LUẬN MỚI CỦA LUẬN ÁN Nghiên cứu và thống kê các vấn đề môi trường và hệ thống xử lý hiện tại đối với nước thải chế biến cao su tự nhiên ở Việt Nam. Phát triển hệ thống xử lý mới, tên gọi BRUASBDHS, nhằm xử lý nước thải có ô nhiễm hữu cơ cao và thu hồi năng lượng dưới dạng khí sinh học. Làm sáng tỏ tác động của sự đa dạng thành phần vi sinh vật đối với phương pháp xử lý sinh học, từ đó có các phương án vận hành để tăng hiệu quả loại chất ô nhiễm và khả năng sản xuất khí sinh học.
MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY Takahiro Watari DEVELOPMENT OF AN APPROPRIATE TREATMENT SYSTEM FOR NATURAL RUBBER INDUSTRIAL WASTEWATER TREATMENT CHEMICAL ENGINEERING DISSERTATION Hanoi – 2019 MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY Takahiro Watari DEVELOPMENT OF AN APPROPRIATE TREATMENT SYSTEM FOR NATURAL RUBBER INDUSTRIAL WASTEWATER TREATMENT Major: CHEMICAL ENGINEERING Code No.: 9520301 CHEMICAL ENGINEERING DISSERTATION SUPERVISORS: Assoc Prof Nguyen Minh Tan Prof Takashi Yamaguchi Hanoi - 2019 ACKNOWLEDGMENT Firstly I would like to thank the teachers in the PhD program, the officers in the Department of Education, Hanoi University of Science and Technology Thank you for all the guidance and support you have made for me while I have fulfilled the dissertation Working with colleagues in the Department of Chemical Engineering has been a privilage I would like to thank you from the bottom of my heart for your constant encouragement Finally I am so glad to have a supervisor like Assoc Prof Nguyen Minh Tan Ever since I have started to work under your supervision, I have learned a lot which really helps me to become a better person Thank you! You are the best supervisor ever I hope to receive some words of encourgement and full support from the readers in order to make my PhD disertation better Hanoi, 2.12.2019 Author of the dissertation Takahiro Watari DECLARATION I hereby certify that the dissertation "Development of an appropriate treatment for industrial rubber industrial wastewater treatment" is my own research project The data and results stated in the doctoral dissertation are honest I hereby declare that the information cited in the doctoral dissertation has been fully originated./ Hanoi, 2.12.2019 ON BEHALF OF SUPERVISORS Author Assoc Prof Nguyen Minh Tan Takahiro Watari TABLE OF CONTENTS Introduction Objective Task Current Problems and its solution State of the art 1.1 Natural rubber 1.1.1 Natural rubber processing process 1.1.2 Natural rubber processing wastewater 1.2 Current treatment technology for natural rubber processing wastewater 1.2.1 Biological aerobic and anaerobic pond 1.2.2 Upflow anaerobic sludge blanket 1.2.3 Anaerobic baffled reactor 1.2.4 Activated sludge process 1.2.5 Swim bed tank 1.2.6 Down flow hanging sponge reactor 1.2.7 Dissolved air floatation 1.2.8 Membrane bioreactor 1.2.9 Combination of treatment system for natural rubber processing wastewater 1.3 Industrial wastewater treatment process 1.3.1 Characteristics of anaerobic wastewater treatment and the degradation pathway of anaerobic digestion 1.3.2 Anaerobic industrial wastewater treatment technology 1.3.3 Characteristics of aerobic wastewater treatment and the degradation 1.4 Greenhouse gas emission from wastewater treatment system Material and methods 2.1 Filed survey 2.1.1 Greenhouse gases collection and analysis 2.2 Laboratory UASB-DHS system 2.2.1 Raw wastewater 2.2.2 System description and operational conditions 2.3 Laboratory scale ABR system 2.3.1 Raw natural rubber processing wastewater 2.3.2 System description and operational conditions 2.4 Pilot UASB-DHS system 2.5 Analysis 2.5.1 Potential of hydrogen 2.5.2 Dissolved oxygen 2.5.3 Chemical oxygen demand Page 2 4 13 14 15 18 21 22 22 24 25 26 27 27 30 31 32 33 33 34 36 36 38 40 40 40 42 44 44 44 44 2.5.4 Biochemical oxygen demand 2.5.5 Suspended solid 2.5.6 Total nitrogen 2.5.7 Ammonia, nitrite and nitrate 2.5.8 Volatile fatty acid (VFA) 2.5.9 Biogas production and composition 45 45 46 46 47 48 Results and Discussions 3.1 Characterization of current wastewater treatment system 3.1.1 Characterization of greenhouse gas emission process from current anaerobic tank 3.2 Development concept of a laboratory scale UASB-DHS system for natural rubber processing wastewater treatment 3.2.1 Process performance of laboratory scale UASB-DHS system 3.3 Development concept of a laboratory scale ABR experiment 3.3.1 Process performance of ABR 3.3.2 Determinates profiles inside the ABR 3.4 Development concept of a pilot scale UASB-DHS system experiment for treatment of natural rubber processing wastewater 3.4.1 Process performance 3.4.2 Nitrogen removal and greenhouse gas emissions 3.4.3 Performance comparison of ABR-UASB-DHS system and existing treatment system 3.5 Design guideline for full scale UASB-DHS system for natural rubber processing wastewater in Vietnam 3.5.1 Reactor design for natural rubber processing wastewater 3.5.1.1 Pre-treatment process for UASB reactor 3.5.1.2 UASB reactor 3.5.1.3 DHS reactor 3.5.2 Calculation of Energy consumption and generation for operation of UASB-DHS system 3.5.2.1Energy consumption of UASB-DHS system 3.5.2.2Energy production of UASB-DHS system 49 49 53 Conclusions Recommendation for future study 91 93 References 95 58 58 65 65 68 70 70 76 80 84 85 85 87 88 89 89 90 Figure list Figure 1.1 Top natural rubber produced countries over the world on 2014 Natural rubber harvested area and production in Vietnam Natural rubber production area in Vietnam Natural rubber manufacturing process Schematic diagram of coagulation process Full scale biological pond in Vietnam Schematic diagram of UASB reactor Various reactor configuration of ABR Basic water flow in conventional activated sludge Principle of downflow hanging sponge reactor and full-scale DHS in India Development history from DHS G1 to DHS G6 Anaerobic digestion scheme of organic compounds Aerobic biological degradation pathway Schematic diagram of open-type anaerobic system Gas sampling system used in this study (A) Location of Thanh Hoa province, Vietnam, (B) Thanh Hoa Rubber Factory, (C) Coagulation process in natural rubber sheet producing process Schematic diagram of the baffled reactor (BR), upflow anaerobic sludge blanket (UASB), and downflow hanging sponge (DHS) combined system (1) Substrate reservoir, (2) pump, (3) pretreatment tank, (4) pump, (5–9) sampling ports, (10) UASB column, (11) Gas solid separator, (12) mixer, (13) heated water column, (14) water bath, (15) desulfurizer, (16) gas meter, (17) distributor Protocol for preparation of natural rubber processing wastewater following actual factory methods Schematic diagram of anaerobic baffled reactor Schematic and photo of the pilot scale ABR-UASB-STDHS system 33 35 36 Present treatment system of a local natural rubber processing factory Biogas composition of compartment 28, 33 and 56 Methane gas emission rate and COD concentration of each compartment 49 Figure 3.4 Figure 3.5 COD mass balance in the OAS Nitrous oxide rate and ammonia concentration in each compartment 55 56 Figure 3.6 Composition of emitted GHGs from near the influent part, 56 Figure 1.2 Figure 1.3 Figure 1.4 Figure 1.5 Figure 1.6 Figure 1.7 Figure 1.8 Figure 1.9 Figure 1.10 Figure 1.11 Figure 1.12 Figure 1.13 Figure 2.1 Figure 2.2 Figure 2.3 Figure 2.4 Figure 2.5 Figure 2.6 Figure 2.7 Figure 3.1 Figure 3.2 Figure 3.3 6 14 17 20 21 23 24 28 31 39 40 41 43 54 55 Figure 3.7 Figure 3.8 Figure 3.9 Figure 3.10 Figure 3.11 Figure 3.12 Figure 3.13 Figure 3.14 the center part, and the effluent part of the OAS Time course of pH and temperature during the operation periods Time course of (a) total COD, (b) soluble COD, (c) TSS, (d) VSS and (e) TN during the operation periods COD mass balance of the influent, BR effluent, and UASB effluent Time course of (A) Total COD and (B) TSS concentrations through phase to phase Soluble COD, acetate and propionate concentrations in ABR on (A) 103 day and (B) 199 day Accumulation of rubber particular in feed pipe and photo of wastewaters Time course of (A) Total COD removal efficiency and organic loading rate of UASB reactor, (B) Total BOD removal efficiency (A) Total nitrogen and (B) ammonia removal efficiency of total system and DHS reactor during phase to phase 60 62 64 67 69 73 75 79 Table list Table 1.1 Table 1.2 Table 1.3 Table 1.4 Table 1.5 Table 1.6 Table 1.7 Table 1.8 Table 2.1 Table 2.2 Table 2.3 Table 2.4 Table 3.1 Table 3.2 Table 3.3 Table 3.4 Table 3.5 Table 3.6 Table 3.7 Characteristics of natural rubber processing wastewater in Vietnam National technical regulation on the effluent of natural rubber processing industry in Vietnam (QCVN 01-MT: 2015/BTNMT) Type of treatment process applied in Vietnam Application of UASB reactor for natural rubber processing wastewater treatment Comparison of technologies used for natural rubber processing wastewater treatment Benefits of anaerobic treatment process Application of anaerobic technology to industrial wastewater Global warming potential of greenhouse gases Water quality of natural rubber processing wastewater obtained from a natural rubber sheet producing factory in Thanh Hoa Province Summary of the initial operational conditions for the two operating phases Operational conditions for anaerobic baffled reactor Initial operational conditions through phases to Water quality in each sampling point at a local natural rubber processing wastewater in Vietnam Summary of process performance of the treatment system Summary of the process parameters of the system during entire experimental period Biogas production and compositions of the UASB reactor Nitrogen concentrations (mg-N·L-1) in the proposed system Characteristics of natural rubber processing wastewater in Thailand, Malaysia and Vietnam Process performance of the existing treatment system for treating natural rubber processing wastewater 11 12 13 17 26 27 30 32 37 38 40 43 51 63 74 75 78 81 83 Abbreviation words list ABR AnMBR BOD BR CL COD DAF DHS DO GHG GRABAA GSS GWP HRT MBR OAS OLR ORP PVC RSS SRB ST SVR TN TSR TSS UASB VFA VSS pH anaerobic baffled reactor anaerobic membrane bioreactor biochemical oxygen demand baffled reactor concentrated latex chemical oxygen demand dissolved air flotation downflow hanging sponge dissolved oxygen greenhouse gas granular-bed anaerobic baffled reactor gas-liquid-solids separation global warming potential hydraulic retention time membrane bioreactor open-type anaerobic system organic loading rate oxidation reduction potential polyvinyl chloride ribbed smoked sheet sulfate-reducing bacteria settling tank standard Vietnamese Rubber total nitrogen technically specified rubber total suspended solids upflow anaerobic sludge blanket volatile fatty acid volatile suspended solids potential of hydrogen 3.5.1.3 DHS reactor According to the laboratory scale and pilot scale experiment, the HRT of DHS reactor was designed hours together with effluent recirculation The sponge volume of the DHS reactor can be calculated by following equation V = Q/HRT = 250 m3 V: sponge volume (m3) Q: Flow rate (m3·day-1) HRT: hydridic retention time (hours) The sponge volume of 250 m3 DHS reactor will be more than 500 m3 of total volume The expected height of DHS rector is more than m, thus it could be considered to install several DHS reactors 88 3.5.2 Calculation of Energy consumption and generation for operation of UASB-DHS system 3.5.2.1 Energy consumption of UASB-DHS system Tandukar et al (2007) demonstrated that UASB-DHS system was cost effective compared with activated sludge process [22] In addition, Tanikawa et al (2016) reported that two stage UASB- DHS system treating natural rubber latex wastewater in Thailand can be reduced 95% of energy consumption [24] The strong point of UASB-DHS system is electricity only required for pumping wastewater to UASB reactor Therefore, electricity consumption can be calculated as below The speciation of centrifugal pump is Flow rate: 1,000 m3·day-1 Lifting height: m The centrifugal pump (GE-4M, Kawamoto pump) was selected for this calculation The electricity consumption of this pump was estimated 7.5 kWh In addition, pump for DHS recirculation is used Therefore, the electricity consumption of this UASBDHS system is 15.0 kWh 89 3.5.2.2 Energy production of UASB-DHS system The UASB reactor could be recovered energy in form as the methane The energy recovery from UASB reactor was calculated flow as; Influent COD: 6,000 mg-COD·L-1 Influent flow rate: 1,000 m3·day-1 Estimated methane recovery ratio (based on influent total COD): 60% Estimated methane production (L-CH4·day-1) = 6,000 (mg-COD·L-1) × 1,000 (m3·day-1) × 60% / 2.857 (g-COD·L-CH4-1) = 1,260 (m3-CH4·day-1) The manual for installation of biomass plant published by Ministry of Environment, Japan mentioned gas power generation unit is 1.8 kWh· m3-CH4 The power generation from UASB reactor can be calculated flow as; The power generation from UASB reactor (kWh) = Methane gas production (1,260 m3-CH4·day-1) × (1.8 kWh·m3-CH4-1) = 2,268 (KWh·day-1) Compared with the electricity consumption and electricity generation, the UASB reactor could be generated approximately 2,000 KWh·day-1 This generated electricity is enough for operating a factory 90 Conclusions The water quality and greenhouse gas emission from the existing treatment system treating natural rubber processing wastewater in Vietnam was surveyed The effluent from existing treatment was exceed the discharge standard In addition, open-type anaerobic system emitted not only methane, but also nitrous oxide had high GWP - The final effluent of existing process was Total COD of 730 mg·L-1, TSS of 200 mg·L-1 and TN of 60 mg-N·L-1, respectively - The emission rates (flux) from m3 of treated RSS wastewater for methane, nitrous oxide, and total GHGs by open-type anaerobic system were calculated as 0.054 tCO2eq·m-3, 0.099 t- CO2eq·m-3, and 0.153 t-CO2eq·m-3, respectively Laboratory scale UASB-DHS system and ABR system was demonstrated treatment of natural rubber processing wastewater Both systems performed good process performance and were capable for treating natural rubber processing wastewater - The laboratory scale UASB reactor performed high-level total COD removal at 92.7 ± 2.3% with an OLR of 12.2 ± 6.2 kg-COD m−3 day−1 and 93.3 ± 19.3% methane recovery, corresponding to the influent and effluent COD concentration of 7,010 ± 1,430 mg-COD·L-1 and 530 ± 220 mg-COD·L-1, respectively - The laboratory scale ABR performed good process performance of 92.3 ± 0.3% COD removal efficiency with OLR of 1.4 ± 0.3 kg-COD·m-3·day-1 without pretreatment corresponding to the influent and effluent COD concentration of 3,420 ± 660 mg-COD·L-1 and 311 ± 218 mg-COD·L-1, respectively Pilot scale UASB-DHS system was operated in an actual natural rubber processing factory - The system generated same effluent quality compared with current treatment system - Approximately 80% of hydraulic retention times can be reduced 91 The system could be significantly reduced GHGes emission The proposed system could be an appropriate treatment system for treating natural rubber processing wastewater in Vietnam - The system achieved high organic removal efficiency together with energy recovery form as methane - The existing treatment system and proposed system need more effective nitrogen process for achieve the discharge standard 92 Recommendation for future study · In this research, energy-recovery type wastewater treatment system UASB- DHS system was applied to natural rubber processing wastewater in Vietnam The key point for application of UASB reactor in natural rubber processing wastewater was combined with efficient pretreatment process ABR system was used in this study, however, accumulation of natural rubber particular in the UASB column is always happed and leaded sludge washed-out Therefore, effective pre-treatment process is need to researched Moreover, the production process of natural rubber should be considered like acid and ammonia addition · Our research and present researches often exceed discharge standard of ammonia and nitrogen contents Effective nitrogen removal process should be researched for achieve the discharged standard Moreover, autotrophic denitrification processes such anammox process would be applied to this wastewater in order to reduce operational cost for wastewater treatment · This study investigated that current anaerobic treatment system emitted large amount of GHGes Therefore, further study for emission principle and reduction methods should be studied 93 PUBLICATION LIST D Tanikawa, K Syutsubo, T Watari, Y Miyaoka, M Hatamoto, S Iijima, M Fukuda, N B Nguyen, T Yamaguchi (2016), “Greenhouse gas emissions from opentype anaerobic wastewater treatment system in natural rubber processing factory”, Journal of Cleaner Production, Vol 119, pp 32–37 P T Tran, T Watari, Y Hirakata, T T Nguyen, M Hatamoto, D Tanikawa, K Syutsubo, M T Nguyen, M Fukuda, L H Nguyen, T Yamaguchi (2017), “Anaerobic Baffled Reactor in Treatment of Natural Rubber Processing Wastewater: Reactor Performance and Analysis of Microbial Community”, Journal of Water and Environment Technology, Vol 15, no 6, pp 241–251 T Watari, T C Mai, D Tanikawa, Y Hirakata, M Hatamoto, K Syutsubo, M Fukuda, N B Nguyen, T Yamaguchi (2017), “Performance evaluation of the pilot scale upflow anaerobic sludge blanket – Downflow hanging sponge system for natural rubber processing wastewater treatment in South Vietnam”, Bioresource Technology, Vol 237, pp 204–212 D Tanikawa, T Watari, T C Mai, M 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improve environmental performance and biogas productivity in rubber latex industry”, Process Safety and Environmental Protection, Vol 94, no C, pp 420–429 100 101 102 ...MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY Takahiro Watari DEVELOPMENT OF AN APPROPRIATE TREATMENT SYSTEM FOR NATURAL RUBBER INDUSTRIAL WASTEWATER TREATMENT. .. Application of UASB reactor for natural rubber processing wastewater treatment Comparison of technologies used for natural rubber processing wastewater treatment Benefits of anaerobic treatment. .. Establishment of an optimal treatment system for natural rubber processing wastewater treatment in Vietnam Following these results, we established an optimal treatment system for natural rubber processing