Tài liệu Treating wastewater from households along mae kha canal using hedychium coronarium – a pilot study in thailand

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURAL AND FORESTRY NGUYEN MINH CHAU TOPIC TITLE: TREATING WASTEWATER FROM HOUSEHOLDS ALONG MAE KHA CANAL USING HEDYCHIUM CORONARIUM A PILOT STUDY IN THAILAND BACHELOR THESIS Study mode : Full-time Major : Environmental Science and Management Faculty : International Program Office Batch : 2014-2018 Thai Nguyen, 21/10/2018 i DOCUMENTATION PAGE WITH ABSTRACT Thai Nguyen University of Agriculture and Forestry Degree Program Bachelor of Environmental Science and Management Student name Nguyen Minh Chau Student ID DTN1454290003 Thesis title Treating wastewater from households along Mae Kha canal using Hedychium coronarium – a pilot study in Thailand Associate. Prof. Dr.Arunothai Jampeetong Department of Biology, Faculty of Science, Chiang Mai University Supervisors PhD. Hoang Hai Thanh Advanced Education Program Office, Thai Nguyen University of Agriculture and Forestry Supervisor’s signature Abstract: Chiang Mai, Thailand is one of the most famous destinations for tourists worldwide. Unfortunately, the water pollution is a problem that has been interfering residents’ life and economic development due to rapid urbanization. One of the most serious cases is Mae Kha canal which is an important feature in Chiang Mai's water system. This research, therefore, aims to help local resident building cost-effective wastewater treatment models called Constructed Wetlands (CWs) in order to filter sewage at household level before it was release into the environment. The experiment consisted of four tanks covered with Hedychium coronarium and four control tanks, all set up at Department of Biology, Faculty of Science - Chiang Mai University. The water sample was collected from municipal sewer then separated by two different buckets in which it was treated with and without oxygen addition throughout six weeks. In this study, Hedychium coronarium – a non-common wetland plant, was selected as it is recorded able to lessen mosquito appearance which certainly is one of the drawbacks of CWs. The experiments goals were to estimate the average percentage of parameters removed by Hedychium coronarium in terms of COD, TSS, PO4-P, NH4-N, NO3-N. The percentage removal in COD, TSS, PO4-P, NH4-N, NO3-N were ii 83%, 82.6%, 93%, 89%, 84.7% respectively. It initially proved that the removal efficiency of Hedychium coronarium is as high as others wetland plants and expected to inspire future researchers in continuing to apply new plants to lessen CWs’ perennial problems and optimize its benefits in wastewater treatment. Keywords: Constructed wetlands (CWs), water quality, Hedychium coronarium, percentage removal. Number of pages 48 pages Date of submission 21/10/2018 iii ACKNOWLEDGEMENT First and foremost, I would like to thank my supervisor Assoc. Prof. Dr. Arunothai Jampeetong for being supportive during my difficult time. She had set an example of excellence as a researcher, mentor, instructor, who always prioritize her students and science. I would like to thank my instructor, Tararag Pincam for always being so patient with me even though I misunderstood and made troubles many times. She always supported me with my works as well as treated me as a sister and gave me various valuable advices in life. I would like to thank my supervisor Dr. Hoang Hai Thanh from Vietnam for her constant support. I would like to say thank to all members in Biology laboratory of Faculty of Science, Chiang Mai University, they were always kind to me and never hesitated to give me a hand. Finally, I would like take this opportunity to extend my sense of gratitude to my family and friends who always believe in me and backing me unceasingly. NGUYEN MINH CHAU iv TABLE OF CONTENTS LIST OF FIGURES .....................................................................................................vii LIST OF TABLES ..................................................................................................... viii LIST OF ABBREVIATION ........................................................................................ ix PART I. INTRODUCTION .......................................................................................... 1 1.1.Background and rationale .......................................................................................... 1 1.2.Objectives .................................................................................................................. 2 1.3. Research questions and hypotheses .......................................................................... 3 1.3.1. Research questions..........................................................................................3 1.3.2. Research hypotheses .......................................................................................3 PART II. LITERATURE REVIEW ............................................................................ 4 2.1. Water pollution in Mae Kha canal............................................................................ 4 2.2. How about solutions? ............................................................................................... 7 2.2.1. Previous solutions ...........................................................................................7 2.2.2. Constructed Wetland ......................................................................................8 2.3. Hedychium coronarium (White Ginger) ................................................................ 12 PART III. MATERIALS AND METHODS ............................................................. 15 3.1. Surveying ................................................................................................................ 15 3.2. Domestic wastewater treatment using CW models with Hedychium coronarium. 16 3.2.1. Materials .......................................................................................................16 3.2.2. Experimental set up .....................................................................................17 3.2.3. Water Sampling and analysis........................................................................19 3.2.4. Statistical analysis .........................................................................................20 PART IV. RESULTS AND DISCUSSION ............................................................... 21 4.1. Surveying results: ................................................................................................... 21 v 4.1.1. General background of the communities ......................................................21 4.1.2. Household’s wastewater management ..........................................................21 4.1.3. How can water pollution in Mae Kha canal affect resident’ lives? ..............22 4.1.4. How resident think about Constructed wetlands? ........................................23 4.2. Domestic wastewater treatment using CW models with Hedychium coronarium. 24 4.2.1. Removal of COD ..........................................................................................24 4.2.2. Removal of TSS ............................................................................................ 26 4.2.3. Removal of PO4-P.........................................................................................28 4.2.4. Removal of NH4-N and NO3-N: ...................................................................30 PART V. CONCLUSION ........................................................................................... 35 REFERENCES ............................................................................................................ 36 APPENDIX................................................................................................................... 43 Appendix 1 .................................................................................................................... 44 Appendix 2 .................................................................................................................... 48 vi LIST OF FIGURES Figure 1.1: Mae Kha canal in city moat .......................................................................... 2 Figure 2.1: Wastewater sources to Mae Kha canal ......................................................... 6 Figure 2.2: Hedychium coronarium .............................................................................. 13 Figure 3.1: Study sites ................................................................................................... 16 Figure 3.2: Designed constructed wetland models. ....................................................... 17 Figure 4.1: Domestic wastewater effluents in resident’ view ....................................... 22 Figure 4.2: Main sources of wastewater before drained out ......................................... 23 Figure 4.3: Resident’ preference towards two constructed wetland size ...................... 24 Figure 4.4: Percentage removal in COD by mass ......................................................... 26 Figure 4.5: Percentage removal in TSS by mass ........................................................... 27 Figure 4.6: Percentage removal in PO₄-P by mass ....................................................... 29 Figure 4.7: Nitrogen transformation in nature ............................................................... 31 Figure 4.8: Percentage removal in NH₄-N by mass ...................................................... 32 Figure 4.9: Percentage removal in NO₃-N by mass ...................................................... 33 Figure A1: Residents worried when talking about Mae Kha canal ............................... 48 vii LIST OF TABLES Table 3.1: The difference between before and after domestic wastewater was added oxygen………………………………………………………………………………...18 Table 3.2: Water analysis using standard methods …………………………………..19 Table 4.1: COD removal mass in percentage after each week …………………….....26 Table 4.2: TSS removal mass in percentage after each week………………………...28 Table 4.3: PO₄-P removal mass in percentage after each week ……………………...29 Table 4.4: NH₄-N removal mass in percentage after each week……………………...32 Table 4.5: NO₃-N removal mass in percentage after each week……………………...33 viii LIST OF ABBREVIATION CWs Constructed wetlands FWS Free water surface HSF Horizontal subsurface flow SSF Subsurface flow VF Vertical flow ix PART I. INTRODUCTION 1.1. Background and rationale In this era, human being is facing water crisis and water pollution due to rapid economic growth since the First Economic Revolution in 18 century. Water pollution is not an unfamiliar topic nowadays, especially in the case of developing countries, where economic development is still depending significantly on natural resources. Moreover, the anthropogenic pollutants from industrial, domestic and agricultural waste are ultimately absorbed by aquatic plants and animals. Thailand, one of Southeast Asia’s tiger economies is facing the same environmental problem. Water quality in Thailand has declined, alarming health risks if water is not purified before consumption. According to Brianna in 2017 there are approximately 43 million Thai people drinking contaminated water, allowing diseases like diarrhea, typhoid and dysentery to enter their system; this water is contaminated primarily by pollutants disposed into rivers and streams. Water quality in Thailand varies throughout the country. In Chiang Mai city, which located in northern Thailand, a city famous for its rich culture heritage but water degradation here has been a serious concern for both resident and local authority in many years, one of the prominent polluted water bodies is Mae Kha canal. Many projects and researches had been carried out to solve that problem, but until now, resident live along the water source still find Mae Kha canal is in poor conditions and gradually turn their back on the canal (Sunantana , 2016). The current situation is shown in Figure 1.1 below. People have complained that the wastewater from local houses especially slums was the main cause of pollution, besides, resident littering also add to the problem (Sunantana, 2016; Harmony, 2006; Unchulee, 2014). This is worsened by environmental policies, which are concerned 1 with city aesthetics rather than environmental rehabilitation or protection (Ribeiro & Srisuwan, 2005). Figure 1.1: Mae Kha canal in city moat Among all of current methods, there is a method which can both achieve high pollutant removal rate and aesthetic appearance that is Constructed wetlands (CWs). Conventional wastewater treatment plants involve large capital investments and operating costs not mention to a large area to build the whole systems. In contrast, Constructed wetlands offer low cost operation and maintenance since no mechanical components or external energy is required (Sohair, 2013). Therefore, in this study, four small duplicates of Constructed wetland planted with Hedychium coronarium were created in greenhouse conditions of Department of Biology, Faculty of Science, Chiang Mai University and treated by domestic wastewater collected from municipal pipe systems along the canal. 1.2. Objectives This study has two objectives, they are: 1. To introduce CWs to resident who live along Mae Kha canal bank. 2 2. To evaluate the percentage removal of pollutant factors in domestic wastewater after treated by CW models using Hedychium coronarium. 1.3. Research questions and hypotheses 1.3.1. Research questions ❖ Question 1: How well local resident accepted the idea of building CWs in their community to treat domestic wastewater? ❖ Question 2: Would the Constructed wetland models used Hedychium coronarium achieve good percentage removal like other wetland plants? 1.3.2. Research hypotheses In this study, question 1 was expected to receive various responses whereas question 2 was expected to test two hypotheses below. Question 2: Would the Constructed wetland models used Hedychium coronarium achieve good percentage removal like other wetland plants? - Null hypothesis (Ho): There is no significant between Hedychium coronarium percentage removal and that in other wetland plants. - Alternative hypothesis (Ha): There is a significant between Hedychium coronarium percentage removal and that in other wetland plants. 3 PART II. LITERATURE REVIEW As one of largest cities in Thailand, Chiang Mai has been through the same development process as Bangkok and other big city after 1950’s, during the urbanization period. Chiang Mai city was found in 1296 under King Mengrai’s rule as the capital of old Lanna Kingdom. At present, it is the center of culture, economics and education of northern Thailand. According to Sangawongse, 2005, the urban area of Chiang Mai increased from 15 km2 in 1952 to 339 km2 in 2000, with a tendency to increase over time. Besides, the number of tourists arrivals in the year 2002, which reached 3,460,886 according to Tourism Authority of Thailand; together cause a dense population in Chiang Mai city, particularly, in 2015 there was 5,000 people per square kilometer bases on a report of The World Bank. This rapid population increase has become a burden to many environmental sources such as water, land, and air. Today, according to the Air Visual app, which monitors air quality around the world, Chiang Mai ranked sixth worst in the world in terms of air pollution, according by US Air Quality Index, not to mention the serious water degradation here which has degraded Chiang Mai image in foreign friends and disturb residents’ lives (The Nation, 2018). 2.1. Water pollution in Mae Kha canal Mae Kha canal defines the historical outer borders of Chiang Mai, and today still accompanies parts of the outer wall as historical monuments. The canal is presently about 16 km long, its width fluctuates seasonally and locally between 1 and 10 m and has an average depth of 2.5 m, which also varies by season and location (Ribeiro & Srisuwan, 2005). Before 1950’s, Mae Kha Canal was an exuberant, beautiful, clean canal that could be used for drinking, fishing, and other functions of daily life. At that time most of land was used for rice paddy and forest, Mae Kha was a 4 major water resource for agriculture, irrigation, and drinking (Sunantana, 2016). However, a 1978 report indicates that the Mae Kha canal was already heavily polluted at that time, with the water quality being classified as standard type 5, that indicated water source was unsuitable for drinking or bathing based on the surface water classification in “Water Quality Standard” Pollution Control Department, Ministry of Natural Resources and Environment (Gustavo, 2005). Water quality became poorer as the result of general drainage discharges from the city as well as the presence of informal settlements located right on the banks of the canal. In 2006, a research from Buffalo State University of New York cooperated with Chiang Mai University examined the impact of Chiang Mai on water quality in the Mae Kha canal that runs through the city, according to them water quality became degraded as it passed through the city, as compared to upstream control sites. Seasonal differences have also impacted pollution rate in Mae Kha canal that the pollution rate in dry season is higher than those in rainy season, due to low water input. In contrast, during rainy season, more water flushes pollution substances down the drain. In the late rainy season, pollution rate tends to raise back again (Christie, 2014). A. Why water in the city center could be that serious degraded? Since urbanization, Chiang Mai attracted poor rural migrants who settled in informal settlements seeking for jobs in inner city, some of which were located on the banks of the Mae Kha canal, lead to the canal getting narrower after a period of time and this caused flooding during the rainy season (Gustavo, 2005). Besides, the way they discharge wastewater directly to the canal adds together with commercial and industrial factories, and urban run-off have worsen the problem, it was visualized in Figure 2.1 below (Sunantana, 2016). 5 Figure 2.1: Wastewater sources to Mae Kha canal source: Sunantana, 2016 B. Domestic wastewater versus industrial wastewater Typically, domestic wastewater is often considered to contain a higher ratio of biodegradable organic matter than that in many of industrial wastewater (Norio, 2011). Industrial factories have their own facilities for treating industrial wastewater and then discharge the treated water into the sewer system (Yun-Young et al., 2013). On the other hand, domestic wastewater is the water that has been used by a community and which contains all the materials added to the water during its use. It is thus composed of human body wastes (faeces and urine) together with the water used for flushing toilets, and sullage, which is the wastewater resulting from personal washing, laundry, food preparation and the cleaning of kitchen utensils , thus contributes a wide variety of chemicals into sewage (Duncan, 2003). To alter water degradation in Mae Kha canal, the consensus of local authority and community is needed to reduce the amount of domestic wastewater as well as commercial and industrial wastewater. 6 2.2. How about solutions? 2.2.1. Previous solutions Conventional systems require significant inputs of chemicals and energy, and need to be operated by specially-trained personnel. Furthermore, the useful life of such systems is limited (25–40 years) and replacement/retrofitting costs to make outdated facilities operational again are significant (Vassiolios, 2017). Therefore, this method is not suitable to apply in tropical countries since most of the developing and the least developed countries are located in tropical and subtropical regions of the world. In these countries, public and private wastewater treatments and disposal systems are often very deficient or even entirely missing (Norio, 2011). Moreover, that is an inadequacy of water treatment plant in Chiang Mai, pointed out by Sunantana in 2016, where the drainage system is a combined system of wastewater and runoff. In rainy season, there is an overload of water in the treatment plant that directly affects a purifying process. With only one treatment plant available, the system to clean water for the entire city before releasing to the natural river is not sufficient. Futhermore, in 1990’s, with support from OECF, Overseas Economic Cooperation Fund organization, Mae Kha was constructed with concrete lining in the urban area, expanded the canal to 2-2.5 meter in depth and 4-5 meter in width in order to improve water flow and reduce erosion. However; this project was not quite successful in long-term management and maintenance program In developing countries, the primary purpose is to protect the public health through control of pathogens to prevent transmission of waterborne diseases (Kivaisi, 2001). For this purpose, simple and cost-effective technologies are suitable and should 7 be encouraged in developing countries in general and tropical developing countries in particular. 2.2.2. Constructed Wetland Today more than ever, with an increase in environmental awareness and corporate social responsibility, biological treatment methods are considering effective alternatives to deal with environmental degradation. One of those methods that has been used worldwide is Constructed Wetlands. A. What is Constructed Wetland? The first constructed wetland was built in Australia in 1904. Such systems are designed to mimic the function and processes of natural ecosystems, such as lakes and wetlands, in treating pollutants, and are called “natural wastewater treatment systems” (Vassiolios, 2017). Another definition of Constructed Wetland by Dr. Kadlec and Mr. Wallace is: “Modern treatment wetlands are man-made systems that have been designed to emphasize specific characteristics of wetland ecosystems for improved treatment capacity. Treatment wetlands can be constructed in a variety of hydrologic modes”. According to Torczon, the basis Constructed wetland structure includes: 1. A basin containing water 2. A substrate 3. Plant life In particular, a basin can be constructed by using the topography of the land and various grading operations. Substrates used in a constructed wetland are depend on the site location and function of the CW. Various soil, gravel, sand, rock, and organic 8 material are typically used as substrates. The type of substrate is very important in determining the type of plant life that will predominant a CW. (Carl et al., 2006). Some common wetland plants are: Canna, Heliconia, Spartina alterniflora, Elodea canadensis, Azolla caroliniana…(Department of Environment, Health and Natural Resources, North Carolina, 1997). In Thailand, the use of CW systems is not widespread but it is expected to be recognized more due to the fact that they are sustainable and energy saving (Suwasa, 2013) since CWs have showed better performances in tropical areas as the warm climate is more conductive to year-round macrophyte growth and microbiological activity (Karin & Hristina, 2007). Some prominent constructed wetlands in Thailand can be name are Ban Pru Teau at Ban Pru Teau, Phang-nga Province; Koh Phi Phi Integrated Wastewater Management System which famous for its special design - the flower and the butterfly park, attracts tourists returning to the island after the tsunami in 2004 (Brix, 2011). B. How wetlands improve water quality? The potential applications of wetlands include the secondary treatment of municipal and certain industrial wastewaters and the polishing of secondary effluent and runoff that would have carried pollution from diffused sources (Norio, 2011). There are four stages in wastewater treatment: Primary treatment (Removes solid matter); Secondary treatment (Uses tiny living organisms knows as micro-organisms to break down and remove remaining dissolved wastes and fine particles); Nutrient removal (Removes nitrogen and phosphorus nutrients that could cause algal blooms in our waterways and threaten aquatic life); Disinfection (Removes disease-causing micro-organisms) based on an article on website of Queensland Government in 2017. 9 CWs can treat various types of wastewater, including, among others: domestic/municipal, industrial, azo-dye and textile, dairy, mine drainage, landfill leachate, agricultural, i.e., animal farms, etc. (Vassilios, 2017). The performance of CWs depends on many factors including its type and design, organic loading rate and hydraulic retention time (Karpiscak, 1999). The pollutants in such systems are removed through a combination of physical, chemical and biological processes including sedimentation, precipitation, and absorption to soil particles, assimilation by the plant tissue, and microbial transformations (Davis, 2006). The most effective treatment wetlands are those that foster the above mechanisms. C. Types of Constructed Wetland Constructed wetlands are categorized into two types as: • Subsurface flow (SSF) • Free water surface (FWS) The subsurface flow CWs could be distinguished further into two types according to the flow direction and level and duration of saturation of the substrate: horizontal subsurface flow (HSF); and vertical flow (VF) and latter, more types had been found name: tidal flow, upflow, downflow and integrated according to Vassilios in 2017. Depend on the targets, different type of constructed wetland could be used. For example, according to EPA in 2000, the main advantages of this subsurface water level (SSF) are prevention of mosquitoes and odors, and elimination of the risk of public contact with the partially treated wastewater; whereas the water surface in free water surface (FWS) constructed wetlands is exposed to the atmosphere with the attendant risk of mosquitoes and public access. 10 Researches indicated that both HSF and VF constructed wetlands produced a high quality effluent. Based on a research of Sohair in 2013, VF was highly recommended more for wastewater treatment because of its smaller size, high quality of treated effluent and less evapo-transpiration rate. Moreover, VF was proved to be promising technique for wastewater treatment not only for COD, BOD and TSS reductions, but also for nitrification removal. In his study, all removal rates of COD, BOD and TSS reached more than 90 percent; these results were almost the same as other studies (Haritash et al., 2015; Konnerup, 2008). From all reasons above, in this study, VF constructed wetland models were selected. D. Roles of Wetland plants Plants in CWs are not only an aesthetic factor but the most important functions of plants are related to their physical effects in the wetlands. The effects were clarified in a research poster of USDA Natural Resources Conservation Service in 2013: “The principal function of vegetation in constructed wetland systems is to create additional environments for microbial population. The stems and leaves in the water column obstruct flow and facilitate sedimentation, and provide substantial quantities of surface area for attachment of microbes, and constitute thin-film reactive surfaces. Plants increase the amount of aerobic microbial environment in the substrate. The wetland plants will prevent erosion, retard the entry of pollutants, and prevent the degradation of water quality in our natural waterways and will function as an attractive environmental study area”. Therefore, plant species that are common to the wettest environment often exhibit the greatest degree and the most effective 11