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 luan an 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: 1. Nguyen Minh Tan 2. Takashi Yamaguchi Hanoi - 2019 luan an 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. 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.2019 Author of the dissertation Takahiro Watari luan an 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.2019 ON BEHALF OF SUPERVISORS Author Assoc. Nguyen Minh Tan Takahiro Watari luan an TABLE OF CONTENTS Page Introduction 1 Objective 2 Task 2 Current Problems and its solution 3 1. State of the art 4 1.1 Natural rubber processing process 7 1.2 Natural rubber processing wastewater 9 1.2 Current treatment technology for natural rubber processing 13 wastewater 1.1 Biological aerobic and anaerobic pond 14 1.2 Upflow anaerobic sludge blanket 15 1.3 Anaerobic baffled reactor 18 1.4 Activated sludge process 21 1.5 Swim bed tank 22 1.6 Down flow hanging sponge reactor 22 1.7 Dissolved air floatation 24 1.9 Combination of treatment system for natural rubber 26 processing wastewater 1.3 Industrial wastewater treatment process 27 1.1 Characteristics of anaerobic wastewater treatment and the 27 degradation pathway of anaerobic digestion 1.2 Anaerobic industrial wastewater treatment technology 30 1.3 Characteristics of aerobic wastewater treatment and the 31 degradation 1.4 Greenhouse gas emission from wastewater treatment system 32 2 Material and methods 33 2.1 Greenhouse gases collection and analysis 34 2.2 Laboratory UASB-DHS system 36 2.2 System description and operational conditions 38 2.3 Laboratory scale ABR system 40 2.1 Raw natural rubber processing wastewater 40 2.2 System description and operational conditions 40 2.4 Pilot UASB-DHS system 42 2.1 Potential of hydrogen 44 2.3 Chemical oxygen demand 44 luan an 2.4 Biochemical oxygen demand 45 2.7 Ammonia, nitrite and nitrate 46 2.8 Volatile fatty acid (VFA) 47 2.9 Biogas production and composition 48 3 Results and Discussions 49 3.1 Characterization of current wastewater treatment system 49 3.1 Characterization of greenhouse gas emission process from 53 current anaerobic tank 3.2 Development concept of a laboratory scale UASB-DHS system for 58 natural rubber processing wastewater treatment 3.1 Process performance of laboratory scale UASB-DHS system 58 3.3 Development concept of a laboratory scale ABR experiment 65 3.1 Process performance of ABR 65 3.2 Determinates profiles inside the ABR 68 3.4 Development concept of a pilot scale UASB-DHS system 70 experiment for treatment of natural rubber processing wastewater 3.2 Nitrogen removal and greenhouse gas emissions 76 3.3 Performance comparison of ABR-UASB-DHS system and 80 existing treatment system 3.5 Design guideline for full scale UASB-DHS system for natural 84 rubber processing wastewater in Vietnam 3.1 Reactor design for natural rubber processing wastewater 85 3.1 Pre-treatment process for UASB reactor 85 3.2 Calculation of Energy consumption and generation for 89 operation of UASB-DHS system 3.1Energy consumption of UASB-DHS system 89 3.2Energy production of UASB-DHS system 90 4 Conclusions 91 Recommendation for future study 93 References 95 luan an Figure list Figure 1.1 Top natural rubber produced countries over the world on 5 2014 Figure 1.2 Natural rubber harvested area and production in Vietnam 6 Figure 1.3 Natural rubber production area in Vietnam 6 Figure 1.4 Natural rubber manufacturing process 8 Figure 1.5 Schematic diagram of coagulation process 9 Figure 1.6 Full scale biological pond in Vietnam 14 Figure 1.7 Schematic diagram of UASB reactor 17 Figure 1.8 Various reactor configuration of ABR 20 Figure 1.9 Basic water flow in conventional activated sludge 21 Figure 1.10 Principle of downflow hanging sponge reactor and full-scale 23 DHS in India Figure 1.11 Development history from DHS G1 to DHS G6 24 Figure 1.12 Anaerobic digestion scheme of organic compounds.13 Aerobic biological degradation pathway 31 Figure 2.1 Schematic diagram of open-type anaerobic system.2 Gas sampling system used in this study.3 (A) Location of Thanh Hoa province, Vietnam, (B) Thanh 36 Hoa Rubber Factory, (C) Coagulation process in natural rubber sheet producing process.4 Schematic diagram of the baffled reactor (BR), upflow 39 anaerobic sludge blanket (UASB), and downflow hanging sponge (DHS) combined system.5 Protocol for preparation of natural rubber processing 40 wastewater following actual factory methods.6 Schematic diagram of anaerobic baffled reactor.7 Schematic and photo of the pilot scale ABR-UASB-ST- 43 DHS system.1 Present treatment system of a local natural rubber 49 processing factory.2 Biogas composition of compartment 28, 33 and 56.3 Methane gas emission rate and COD concentration of each 55 compartment.4 COD mass balance in the OAS 55 Figure 3.5 Nitrous oxide rate and ammonia concentration in each 56 compartment.6 Composition of emitted GHGs from near the influent part, 56 luan an the center part, and the effluent part of the OAS.7 Time course of pH and temperature during the operation 60 periods.8 Time course of (a) total COD, (b) soluble COD, (c) TSS, (d) 62 VSS and (e) TN during the operation periods.9 COD mass balance of the influent, BR effluent, and UASB 64 effluent.10 Time course of (A) Total COD and (B) TSS concentrations 67 through phase 1 to phase 3 Figure 3.11 Soluble COD, acetate and propionate concentrations in 69 ABR on (A) 103 day and (B) 199 day Figure 3.12 Accumulation of rubber particular in feed pipe and photo of 73 wastewaters Figure 3.13 Time course of (A) Total COD removal efficiency and 75 organic loading rate of UASB reactor, (B) Total BOD removal efficiency.14 (A) Total nitrogen and (B) ammonia removal efficiency of 79 total system and DHS reactor during phase 1 to phase 4. luan an Table list Table 1.1 Characteristics of natural rubber processing wastewater in 11 Vietnam.2 National technical regulation on the effluent of natural 12 rubber processing industry in Vietnam.3 Type of treatment process applied in Vietnam.4 Application of UASB reactor for natural rubber processing 17 wastewater treatment.5 Comparison of technologies used for natural rubber 26 processing wastewater treatment.6 Benefits of anaerobic treatment process.7 Application of anaerobic technology to industrial 30 wastewater Table 1.8 Global warming potential of greenhouse gases.1 Water quality of natural rubber processing wastewater 37 obtained from a natural rubber sheet producing factory in Thanh Hoa Province.2 Summary of the initial operational conditions for the two 38 operating phases.3 Operational conditions for anaerobic baffled reactor.4 Initial operational conditions through phases 1 to 4.1 Water quality in each sampling point at a local natural 51 rubber processing wastewater in Vietnam Table 3.2 Summary of process performance of the treatment system.3 Summary of the process parameters of the system during 74 entire experimental period.4 Biogas production and compositions of the UASB reactor.5 Nitrogen concentrations (mg-N·L-1) in the proposed 78 system.6 Characteristics of natural rubber processing wastewater in 81 Thailand, Malaysia and Vietnam Table 3.7 Process performance of the existing treatment system for 83 treating natural rubber processing wastewater.
luan an Abbreviation words list ABR anaerobic baffled reactor AnMBR anaerobic membrane bioreactor BOD biochemical oxygen demand BR baffled reactor CL concentrated latex COD chemical oxygen demand DAF dissolved air flotation DHS downflow hanging sponge DO dissolved oxygen GHG greenhouse gas GRABAA granular-bed anaerobic baffled reactor GSS gas-liquid-solids separation GWP global warming potential HRT hydraulic retention time MBR membrane bioreactor OAS open-type anaerobic system OLR organic loading rate ORP oxidation reduction potential PVC polyvinyl chloride RSS ribbed smoked sheet SRB sulfate-reducing bacteria ST settling tank SVR standard Vietnamese Rubber TN total nitrogen TSR technically specified rubber TSS total suspended solids UASB upflow anaerobic sludge blanket VFA volatile fatty acid VSS volatile suspended solids pH potential of hydrogen luan an Introduction Natural rubber is one of the most valuable agricultural products in Southeast Asian countries. Vietnam is the 3rd largest natural rubber-producing country, and natural rubber production in Vietnam is increasing each year. However, the natural rubber industry discharges large amounts of wastewater containing high concentrations of organic compounds, nitrogen, and other contaminants from several manufacturing processes such as coagulation, centrifugation, lamination, washing, and drying. The natural rubber processing factories in Southeast Asian countries commonly use a combined anaerobic-aerobic lagoon system for treating natural rubber processing wastewater because of the low installation costs.
The existing treatment systems have been demonstrated to achieve a high chemical oxygen demand (COD) removal efficiency of 65 to 90% with easy operational methods. However, they require a large area for the lagoon, high operating costs (especially for surface aeration), and long hydraulic retention times (HRTs). However, the effluent water quality of these existing treatment systems needs to be improved in order to conform to the established discharge standards. An upflow anaerobic sludge blanket (UASB) reactor is one of the most promising systems for the treatment of different types of industrial wastewater because of its high organic loading rate (OLR), low operational costs, and energy recovery in the form of methane.
Previous studies have reported the application of the UASB reactor for the treatment of natural rubber processing wastewater. However, it was determined that natural rubber particles remaining in the wastewater had a negative effect on the anaerobic biological process. Therefore, the development of a pre-treatment system to remove the remaining natural rubber particles is essential. Moreover, when a UASB reactor is used to treat high-strength industrial wastewater, the effluent still contains high concentrations of organic compounds and nutrients.
Thus, an aerobic treatment system is typically applied as a post-treatment to remove residual organic matter and meet effluent standards. A downflow hanging sponge (DHS) reactor is one of the most effective aerobic treatment systems applied as a 1 luan an post-treatment with the UASB reactor to treat different types of industrial wastewaters. Objective Current wastewater treatment systems used to treat natural rubber processing wastewater in Vietnam consume a large amount of electrical energy and have a large negative impact on the environment. In this study, we characterized the process performance (e., water quality and biogas emission) of the current wastewater treatment system and developed an energy-recovery type advanced wastewater treatment system to reduce greenhouse gases (GHGes) emission and improve the effluent quality resulting from the treatment of natural rubber processing wastewater.
Tasks (Scientific and practical meanings) 1) Characterization of the current wastewater treatment system used to treat natural rubber processing wastewater in Vietnam To investigate the current situation of natural rubber processing wastewater treatment in Vietnam, field and journal paper surveys were conducted. Moreover, greenhouse gas emissions from an existing anaerobic lagoon were measured to determine the environmental impact on global warming. This research will make clear problems in current situation of natural rubber processing wastewater treatment in an actual site. Moreover, GHGes emission from current wastewater treatment system firstly investigated.
2) Development of an energy-recovery type wastewater treatment system The UASB-DHS system has been applied to treat domestic sewage and several types of wastewater. In addition, the UASB-DHS system was successfully applied in Thailand to treat natural rubber processing wastewater, which contained a high concentration of sulfuric acid.