Tài liệu Intensified phosphorus removal from synthetic wastewater by lab scale horizontal sub surface flow constructed wetlands using a mixture of coal slag and calcined ferralsols as substrate

VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY LE THI VAN INTENSIFIED PHOSPHORUS REMOVAL FROM SYNTHETIC WASTEWATER BY LAB-SCALE HORIZONTAL SUB-SURFACE FLOW CONSTRUCTED WETLANDS USING A MIXTURE OF COAL SLAG AND CALCINED FERRALSOLS AS SUBSTRATE MASTER'S THESIS VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY LE THI VAN INTENSIFIED PHOSPHORUS REMOVAL FROM SYNTHETIC WASTEWATER BY LAB-SCALE HORIZONTAL SUB-SURFACE FLOW CONSTRUCTED WETLANDS USING A MIXTURE OF COAL SLAG AND CALCINED FERRALSOLS AS SUBSTRATE MAJOR: ENVIRONMENTAL ENGINEERING CODE: 8520320.01 SUPERVISORS: Principal Supervisor: Dr. NGUYEN THI AN HANG Co-Supervisor: Assoc. Prof. Dr. SATO KEISUKE Hanoi, 2020 ACKNOWLEDGEMENTS First and foremost, I would like to express my deep gratitudes to Dr. Nguyen Thi An Hang, my Principal Supervisor, who gave me the opportunity to get involved in this interesting research. She not only provided me valuable advices on this research but also strengthened my research skills, built up my confidence, and encouraged me to overcome all difficulties. It would have been impossible to fulfill this work without her enthusiastic supports. I extend my sincere thanks to Assoc. Prof. Dr. Sato Keisuke, my Co-supervisor, who gave me practical advices on the feasibility and applicability of my research. It was very kind of him to give me opportunities to learn about Japanese culture and people, which will definitely be useful for my future. My gratitude is also gone to Dr. Vu Ngoc Duy for his extraordinary supports. I was immensely benefited from his continuous assistance in constructed wetlands setting up and experimental data processing. My special thanks go to B.Sc. Nguyen Thi Xuyen, the project assistant, for her helps with taking care of CWs system during the global COVID-19 pandemic period. For me, she is a sincere friend and I have learnt a lot from her. I would like to acknowledge VNU Vietnam Japan University (VJU), Ritsumeikan University (RITs), and Hiyoshi Corporation for providing me the best conditions to study and have internship in Vietnam and Japan. Especially, I am so grateful to Prof. Jun Nakajima and Prof. Soda Satoshi for teaching me at VJU and supporting me during my internship in Japan. This research was completed in the laboratory of the Master’s Program in Environmental Engineering (MEE), VNU Vietnam Japan University (VNU-VJU). I would like to acknowledge Vietnam National Foundation for Science and Technology Development (NAFOSTED) [grant number 105.99-2018.13, 2018], and Asia Research Center, Vietnam National University, Hanoi (ARC-VNU) and Korea Foundation for Advanced Studies (KFAS) [grant number CA.18.11A, 2018] for financial supports. i Lastly, I would like to express my deep gratitudes to my parents for raising me with a love of science and supporting me in all my pursuits. My heartfelt thanks go to Son-san for his love, accompanying, and comments on my thesis research. Thank you all my friends, who were MEE Batch 3 students, for unforgettable memories. Hanoi, June 14th 2020 Le Thi Van ii TABLE OF CONTENTS ACKNOWLEDGEMENTS...............................................................................................i TABLE OF CONTENTS................................................................................................ iii LIST OF TABLES...........................................................................................................vi LIST OF FIGURES........................................................................................................ vii LIST OF ABBREVIATIONS...........................................................................................x INTRODUCTION............................................................................................................ 1 CHAPTER 1: LITERATURE REVIEW..................................................................... 4 1.1. Pig farming in Vietnam..................................................................................... 4 1.1.1. Pig farming development in Vietnam..................................................... 4 1.1.2. Environmental concerns of anaerobically treated swine wastewater...5 1.2. Phosphorus pollution and remedy technologies................................................8 1.2.1. Phosphorus significance and environmental concern........................... 8 1.2.2. Technologies for phosphorus decontamination of anaerobically treated swine wastewater (ATSWW).............................................................. 10 1.3. Constructed wetlands.......................................................................................11 1.3.1. Definition.............................................................................................. 11 1.3.2. Classification of constructed wetlands (CWs)..................................... 12 1.3.3. Phosphorus removal by different components in CWs........................ 14 1.3.4. Advantages and disadvantages of CWs in P removal from wastewater...................................................................................................... 21 1.4. Study subjects.................................................................................................. 22 1.4.1. Filter materials..................................................................................... 22 1.4.2. Plants.................................................................................................... 26 CHAPTER 2: MATERIALS AND METHODS........................................................28 2.1. Materials...........................................................................................................28 2.1.1. Substrates..............................................................................................28 iii 2.1.2. Wetland plants...................................................................................... 31 2.2. Experimental set-up......................................................................................... 33 2.2.1. Ferralsols calcination.......................................................................... 33 2.2.2. Adsorption tests.................................................................................... 34 2.2.3. Constructed wetlands design and operation........................................36 2.3. Analytical methods and equipment................................................................. 38 2.3.1. Substrate characterization....................................................................38 2.3.2. Environmental parameters analysis.....................................................41 2.4. Calculation and statistical analysis..................................................................44 2.4.1. Calculation............................................................................................44 2.4.2. Statistical analysis................................................................................ 44 CHAPTER 3: RESULTS AND DISCUSSION..........................................................45 3.1. Ferrasols calcination for P removal enhancement.......................................... 45 3.1.1. Lab-scale Ferralsols calcination......................................................... 45 3.1.2. Large-scale Ferralsols calcination...................................................... 46 3.2. Adsorptive behaviours of calcined Ferrasols.................................................. 46 3.2.1. Factors influencing P adsorption.........................................................46 3.2.2. Adsorption isotherms............................................................................50 3.2.3. Adsorption kinetics............................................................................... 55 3.3. Characterization of the filter materials............................................................57 3.3.1. Characterization of natural and calcined Ferralsols.......................... 57 3.3.2. Characterization of coal slag............................................................... 64 3.4. Applicability of the investigated filter materials.............................................66 3.5. Treatment performance of sub-surface horizontal flow constructed wetlands...................................................................................................................67 3.5.1. P treatment performance......................................................................67 3.5.2. Side-effects of filter materials on HSSF-CWs effluents....................... 69 CHAPTER 4: CONCLUSIONS AND RECOMMENDATIONS............................73 iv 4.1. Conclusions......................................................................................................73 4.2. Recommendations............................................................................................73 REFERENCES................................................................................................................75 APPENDICES.................................................................................................................89 v LIST OF TABLES Table 1.1. Treatment efficiency of piggery wastewater by anaerobically treatment in Thua Thien Hue .............................................................................................. 7 Table 1.2. P removal mechanisms of CWs components ..............................................14 Table 1.3. Effect of nutrient uptake by plants on removal of nitrogen and phosphorus (%) in different CWs simulated scenarios ................................19 Table 2.1. Parameters of real post-anarobically swine wastewater in Hanoi................ 33 Table 3.1. Comparison of P adsorption capacity of investigated filter materials..........45 Table 3.2. Coparing CF500 produced in lab-scale and large-scale............................... 46 Table 3.3. Langmuir and Freundlich adsorption isotherm constants.............................53 Table 3.4. P adsortion capacity of different materials....................................................54 Table 3.5. Kinetic constants............................................................................................57 Table 3.6. Mineral composition of NF and CF500 samples.......................................... 60 Table 3.7. Main chemical compositions of NF, CF500 and CS.................................... 60 Table 3.8. Types of vibration peak in NF and CF500....................................................62 Table 3.9. The chemical compositions in CF500 and NF..............................................62 Table 3.10. Hydraulic properties of CF500 compared with other materials................. 64 Table 3.11. The chemical compositions in CS...............................................................65 Table 3.12. Physical properties of CS compared with other materials..........................65 Table 3.13. Selection the mixing ratio of CF500 and CS.............................................. 66 Table 3.14. The concentration of 6 heavy metals in post-adsorption solutions............ 71 vi LIST OF FIGURES Figure 1.1. Distribution of pig production in Vietnam by ecological regions .......... 5 Figure 1.2. Swine wastewater .....................................................................................6 Figure 1.3. P is an important and essential nutrient for plants .................................. 8 Figure 1.4. HABs are triggered by nutrient enrichment ............................................ 9 Figure 1.5. Stabilization lagoon................................................................................. 11 Figure 1.6. Classification of CWs ............................................................................ 12 Figure 1.7. The diagram of VSSF-CWs ...................................................................13 Figure 1.8. HSSF-CWs .............................................................................................14 Figure 1.9. P adsorption mechanism on material surface ........................................ 16 Figure 1.10. Phytoremediation Using Aquatic Plants ..............................................17 Figure 1.11. Rhizosphere in CWs plants ..................................................................18 Figure 1.12. Phosphorus cycle in constructed wetland ............................................18 Figure 1.13. Source structure of the national electricity system by primary energy 22 Figure 2.1. Pha Lai Thermal Power Joint Stock Company....................................... 28 Figure 2.2. Principle diagram of electricity production technology..........................29 Figure 2.3. Sampling location of Ferralsols in Dak Nong Province......................... 30 Figure 2.4. Stone placed at the bottom of CW units..................................................31 Figure 2.5. Sand added on the top of CWs units....................................................... 31 Figure 2.6. Aquatica ipomoea planted from seeds on the soil before being transferred into CW units....................................................................................32 Figure 2.7. Cymbopogon citratus kept alive in the tap water before being transferred into CW units...................................................................................................... 32 Figure 2.8. Aquatica ipomoea at the time being tranferred into CWs.......................32 Figure 2.9. Carbolite furnace ....................................................................................33 Figure 2.10. Preparing NF for calcination with the commcerical furnace................ 34 Figure 2.11. Layers structure of tanks in CWs.......................................................... 37 Figure 2.12. Nutrient solution storage tank................................................................38 vii Figure 2.13. The HSSF-CWs system planted with water spinach and lemongrass.. 38 Figure 2.14. AMRAY Model 1830 Scanning Electron Microscope......................... 40 Figure 2.15. Empyrean equipment ........................................................................... 40 Figure 2.16. X-ray fluorescence spectrometer .......................................................... 41 Figure 2.17. FTIR Spectrometer .............................................................................. 41 Figure 2.18. Shaker ...................................................................................................42 Figure 2.19. UV/Vis Diode Array Spectrophotometer ............................................ 42 Figure 2.20. The pH meter ....................................................................................... 42 Figure 2.21. The SensION + EC5, Hach, China........................................................43 Figure 2.22. Atomic absorption spectrophotometer ................................................ 43 Figure 3.1. Effect of pH of NF and CF500 on P removal......................................... 47 Figure 3.2. Effect of dosage of NF and CF500 on P removal................................... 49 Figure 3.3. Effect of temperature of CF500 on P removal........................................ 50 Figure 3.4. The fitting Langmuir and Freundlich isotherm models.......................... 51 for P adsorption by CF500......................................................................................... 51 Figure 3.5. The fitting Langmuir and Freundlich isotherm models for P adsorption by NF...................................................................................................................51 Figure 3.6. The fitting Langmuir and Freundlich isotherm modelts for P adsorption by CS................................................................................................................... 52 Figure 3.7. Linear form of adsorption isortherms: a) Langmuir model and b) Freundlich model of CF500................................................................................52 Figure 3.8. Linear form of adsorption isortherm following a) Langmuir model and b) Freundlich model of NF......................................................................................53 Figure 3.9. Linear forms of adsorption isortherms: a) Langmuir model and b) Freundlich model of CS......................................................................................53 Figure 3.10. Kinetic curve of CF500..........................................................................55 Figure 3.11. Kinetic curve of NF............................................................................... 56 Figure 3.12. Kinetic curve of of CS........................................................................... 56 Figure 3.13. SEM observation for a) NF and b) CF500............................................ 58 Figure 3.14. XRD spectrum of NF.............................................................................59 Figure 3.15. XRD spectrum of CF500....................................................................... 59 viii Figure 3.16. FTIR analysis for NF and CF500.......................................................... 61 Figure 3.17. The P removal efficiency of 4 units of CWs......................................... 67 Figure 3.18. The change of P concentration in the effluent over the time................ 68 Figure 3.19. pH of post-adsorption solutions.............................................................70 Figure 3.20. EC of post-adsorption solutions............................................................ 71 ix LIST OF ABBREVIATIONS ATP Adenosine triphosphate BOD Biochemical oxygen demand COD Chemical oxygen demand CWs Constructed wetlands DNA Deoxyribonucleic acid DO Oxygen demand FAO Food and agriculture organization FWS-CWs Free water surface constructed wetlands HSSF-CWs Horizontal sub-surface flow constructed wetlands N Nitrogen P Phosphorus RNA Ribonucleic acid SSF-CWs Sub-surface flow constructed wetlands SS Suspended solid TKN Total Kjeldahl nitrogen TP Total phosphate VSSF-CWs Vertical sub-surface flow constructed wetlands x INTRODUCTION According to the Food and Agriculture Organization (FAO), Asia is one of the largest producers and consumers of livestock products (Vu, 2019). The pig breeding industry in Asia develops at a very fast pace but it is mainly spontaneous and has not yet met the technical standards of breeding facilities and breeding techniques (Le, 2014). Therefore, the swine wasteawter normally contains high levels of pathogens, nirogen (N), and phosphorus (P) (Vietnam National Environment Report, 2014). Nowadays, there are variable technologies for treating livestock wastewater such as: The upflow sludge blanket filteration, USBF (Truong, 2010); stabilization lakes (Nguyen, 2011); upflow anaerobic sludge blanket, UASB (Rodrigues, 2010), anaerobic reactor of expanded granular sludge bed - EGSB (Lee, 2012). In Vietnam, anaerobic treatment is considered an appropriate solution to treat wastewaters containing high contents of organic matter and suspended solids such as swine wastewater. However, this technology is not the final stage in the treatement system to ensure the criteria for safe discharge into the environment (Nguyen, 2012). Therefore, it is necessary to implement additional treatment to swine wastwater after anaerobic treatment before discharging it into the environment. Phosphorus is an important element in all known life forms. Inorganic P in the form PO43- plays an important role in biological molecules such as Deoxyribonucleic acid (DNA) and Acid ribonucleic (RNA). On the other side, P at high concentration is one of the causes of water pollution with phenomena known as eutrophication and toxic algae. According to QCVN 40: 2011/BTNMT (column B), the discharge limit for P in the industrial wastewater is 6 mg/L. Constructed wetland (CW) is one of technologies for wasteawter treatment, which is based on the natural functions of filter materials, platns and microorganisms (Vymazal, 2007). CWs have many advantages, namely simple operation, less maintaining demand, low energy requirement, green teachnology, and especially are suitable for small communities as a decentralized technology (Wu, 2015). 1 In the CWs, P can be removed from wastewater via several pathways, such as sorption onto filter materials, plant uptake and microbial assimilation (Vymazal, 2008). Of which, the role of filter materials is domninant, with the removal mechanisms as follows: adsorption, precipitation, settling, etc. (Wu et al., 2015). Regarding the P treatment performance, the horizontal subsurface flow CWs (HSSF-CWs) were found to be more efficient than other types of CWs, such as vertical subsurface flow CWs (VSSF-CWs), free water surface CWs (FWS-CWs) (Arun,2019). Even in the HSSF-CWs, their P removal ability is usually low and unstable. To overcome this challenge, this study aims at enhancing the P removal efficiency of HSSF-CWs by utilizing a mixture of an industrial by-product (coal slag) and a natural material (Ferralsols) as the filter materials and accumulating plants, namely water spinach (Aquatica ipomoea) and lemongrass (Cymbopogon citratus). To achieve this ultimate goal, a research titled “Intensified phosphorus removal from synthetic wastewater by lab-scale horizontal sub-surface flow constructed wetlands using a mixture of coal slag and calcined ferralsols as substrate” was carried out with the specific objectives as follows: (i) Improve P sorption capacity of raw ferralsols (NF) by calcination, (ii) Investigate the adsorption behaviors, (iii) Evaluate the P treatment performance of the HSSF-CWs using mixture of filter materials and acumulating plants, and (iv) Elucidate possible side-effects of using the selected media in HSSF-CWs. This thesis comprises of 4 main Chapters with the following major contents: Introduction: This part gave the research background, objectives, scope and scale, and research significance. Chapter 1. Literature review: This Chapter provided overall information about environmental problems related to P pollution, the discharge standsards for P containing wastwater, numerous technologies for P decontamination from wastewater. In addition, the composition of swine wastwater after anaerobic treatment was investigated. Especially, this chapter focuses on the CWs, highlighting the roles of filter media and wetland plants. 2 Chapter 2. Materials and methods: This Chapter introduced materials, methods and equipments used for this research. Also, the experimental set-up was described in details. Chapter 3. Result and discussion: This Chapter referred the results on calcination of Ferralsols for strengthenning its P removal ability, characterization of raw and calcined materials, adsorption behaviors, and treatment perfomance of the HSSF-CWs using the selected filter materials and plants, and side-effects of using materials in HSSF-CWs. Chapter 4. Conclusions and recommendations: This Chapter provided the key findings obtained from this results as well as suggestions for future research. Appendices. This part consisted of pictures of research activities of this work. 3 CHAPTER 1: LITERATURE REVIEW 1.1. Pig farming in Vietnam 1.1.1. Pig farming development in Vietnam According to the Food and Agriculture Organization (FAO), Asia will become the largest producer and consumer of livestock products (Vu, 2019). Therefore, Vietnam's livestock needs to maintain a high growth rate to meet the domestic consumption demand and to serve the export. According to the Ministry of Agriculture and Rural Development (MARD), the annual growth rate of the livestock in the period of 2008-2019 was relatively high and stable, representing 5-6%. In the draft Strategy for livestock development (Ministry of Industry and Trade, 2019) from 2020 to 2030, the average annual growth rate for the periods of 2020-2025 and 2025-2030 were predicted to be 4-5% and 3-4%, respectively. Livestock in general and pig production contribute significantly to Vietnam's GDP growth. According to the Global Environmental Strategy Institute, agriculture sector accounted for 25% of the country's GDP in 2014. In particular, the pig industry represented 71% of the GDP of the entire agriculture sector (Pham, 2017). The number of pig farming households with a scale of 100 pig heads or more was 30,926, accounting for 1.04% of the total pig breeding households throughout the country [1]. However, small-scale animal husbandry still dominates due to the conditions in Vietnam. Pig production is concentrated mainly in areas Red River Delta and Northem Uplands according to the result presented in Figure 1.1. 4 Figure 1.1. Distribution of pig production in Vietnam by ecological regions (Nguyen, 2017a) 1.1.2. Environmental concerns of anaerobically treated swine wastewater According to the study of Le (2014), the pig breeding industry develops at a very fast pace but it is mainly spontaneous and has not yet met the technical standards of breeding facilities and breeding techniques. Pollution caused by pig breeding includes solid waste, air pollution and water pollution. One pig emits 1.5 kg of manure daily and gradually increases with body weight. Livestock solid waste contains large amounts of organic matter from manure, uneaten food, straw, etc. It contains many pathogenic microorganisms and high nitrogen (N), phosphorus (P) content (National Environment Report 2014). On the other hand, livestock and slaughtering contribute up to 26% of greenhouse gas emissions (GHGs) in the total emissions caused by animals (Tambone, 2015). In addition, odor is also a cause of air pollution in the livestock sector. However, livestock wastewater is the most significant source of pollution. This is a type of wastewater generated from livestock activities including urine, rinse water, and bathing water for cattle and may contain part or all of animal manure. Wastewater accounts for the majority of livestock wastes because 1 kg of livestock solid waste can be mixed with 20 to 49 kg of water (Nguyen, 2011b). 5 Figure 1.2. Swine wastewater (Nguyen, 2019a) Nowadays, there are various technologies for treating livestock wastewater such as The Upflow Sludge Blanket filtration, USBF (Truong, 2010); Stabilization lakes (Nguyen, 2011); Upflow anaerobic sludge blanket, UASB (Rodrigues, 2010), Anaerobic reactor of expanded granular sludge bed - EGSB (Lee, 2012). However, the most common technology in livestock wastewater treatment is anaerobically digestion. According to Cu (2012), biogas technology is commonly used to produce electricity and heat in the developing countries. Anaerobically digestion have ability to reduce emissions GHGs from manure and generating renewable energy (Møller, 2004; Sommer, 2004). There are millions of biogas tanks overworld, in which, roughly 3.8 million are located in India, about 60,000 tanks in Bangladesh and about 30 million tanks were built in China (Cu, 2012). In Vietnam, Biogas is considered an appropriate solution to treat wastes contain high concentrations of organic matter and solids such as pig wastewater. However, the biogas systems are not the final treatment system to ensure the criteria for safe discharge into the environment (Nguyen, 2012). According to previous studies, the parameters of wastewater after the anaerobically digestion exceeded the permitted standard many times. 6 Table 1.1. Treatment efficiency of piggery wastewater by anaerobically treatment in Thua Thien Hue (Nguyen, 2012) Inffluent TT Parameter Unit 1 BOD5 2 Effluent concentration concentration Efficiency (%) QCVN 40:2011/ BTNMT ( TB±s ) ( TB±s ) mg/L 1297±201 307±90 76,3±7,1 50 COD mg/L 3022±597 463±127 84,7±5,1 150 3 SS mg/L 2674±712 373±123 86,1±5,4 100 4 VSS mg/L 1674±485 244±96 85,4±6,1 - 5 TKN mg/L 608±87 536±89 11,81±6,0 40 6 T-P mg/L 342±92 318±84 7,0±0,03 6 Fecal MPN coliform /100 21,7×106 10,6×106 51,2 (F.coli) mL 7 (column B) - Accordingly, despite the high treatment efficiency of over 70% for many parameters, the quality of water after the anaerobically treatment is still not reached the standard to be discharged into the environment. In detail, BOD5 is 6 times higher, COD is 3 times, TKN is 13 times, and TP is 57 times higher than the standard. This result has also been supported by other studies (Ho, 2016; Le, 2017). In addition, the low treatment efficiency of nutrients (N, P) will create a burden on the receiving source. Therefore, it is necessary to take additional steps to treat wastewater after anaerobically treatment before discharging into the environment. Thus, it can be concluded that pigs breeding is an industry that can bring huge economic benefits but also certain environmental risks. In particular, the negative effects caused by livestock wastewater are the most significant. Therefore it is necessary to study and select appropriate and effective technologies to treat in order to prevent negative impacts from livestock wastewater. 7 1.2. Phosphorus pollution and remedy technologies 1.2.1. Phosphorus significance and environmental concern On the one side, P is an important element in all known life forms. Inorganic P in the form PO43- plays an important role in biological molecules such as DNA and RNA. Living cells also use P to transport cellular energy through ATP. Almost process in the cell that uses energy has P in its ATP form. Despite being the 11th most abundant element on earth, P in nature exists only in the form of P ore and this is an almost unrecoverable resource (when it takes 10-15 million years to recover) (Do, 2008). In agriculture, P is an important and essential nutrient for plants, P deficiency is one of the causes of crop productivity decline (Ryan, 2012). Figure 1.3. P is an important and essential nutrient for plants (Pennsylvania's Nutrient Management Act Program, 2005) On the other side, P is one of the causes of water pollution in the presence exceeding concentrations. The recognizable manifestation of P pollution are eutrophication leading to algal blooms. An excessive increase in nutrients, especially P in surface water, leads to low DO levels, killing fish and aquatic organisms (Iodache, 2014). Various species of algae (such as microsystis) can produce dangerous toxins during their life cycle, which are the causes of fishes and aquatic plants death, destroying ecological balance (Sathasivan, 2009). In addition, 8