LEE- Çevre Biyoteknolojisi-Yüksek Lisans
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ÖgeSimulation of water resource recovery facilities with an open source software(Graduate School, 2022-02-11)Digitalization is in an uprising trend for more than a decade on many aspects of wastewater treatment processes and these days we are coming across with the term more than ever. Simulation softwares are virtual platforms, a projection of a particular configuration created by the users that can process the data provided with the help of consistent mathematical model implementations. By doing this, environmental engineers are able to control and optimize the operational parameters and use if for finding the most cost-efficient treatment configuration while upgrading an existing facility process scheme or even before constructing it. In other words, engineers can prevent excessive construction and operational costs along with excessive energy consumptions. The motivations of this thesis study is to emphasize the need for popularizing creating functionable softwares with user friendly interfaces, creating specific softwares for divergent configurations and usage of modelling in academy as it is so benefitial for the students to familiarize with the fundamentals of modeling during their undergraduate lectures in terms of the convenience it provides for operational and kinetic parameters. An open-source software able to perform simulations of water resource recovery facilities with Modified Ludzack-Ettinger configuration has been developed within the scope of this study. Python programming language has been chosen for the development of the software due to its easy to learn syntax and its open-source libraries that contain powerful packages such as NumPy, SciPy, PySide2, Matplotlib and Pandas. The data handling of inputs and outputs have been achieved with the help of useful built-in functions of NumPy and Pandas, whereas the graphical user interface of the software have been created with PySide2. SciPy.integrate's solve_ivp function has been used for performing computations of ordinary differential equations with the backward differentiation formula (BDF) method which is a multi-step variable-order implicit method used in solving stiff problems. Lastly for the development phase, figure canvas class of Matplotlib package has been integrated to the interface for visualizing the results of performed simulations. A biochemical process model, consisting of 10 processes and 2 operational parameters defined for 15 state variables, have been created for the specific configuration that includes hydrolization processes of rapidly hydrolyzable COD, slowly hydrolyzable COD, soluble organic nitrogen and particulate organic nitrogen along with the growth and decay processes of heterotrophic and autotrophic biomasses. Activated Sludge Model No. 1 (ASM1) has been taken as a base model for the creation of software model meanwhile endogenous respiration process definitions for two different heterotrophic organism species were adopted from the Activated Sludge Model No. 3 (ASM3). Modifications have been made to the hybrid process model as the ammonification of soluble organic nitrogen process from Activated Sludge Model No. 1 and the storage mechanism of Activated Sludge Model No. 3 were removed from the process model in this thesis study. Once the process model was created, mass balance equations of each state variable were implemented in the software. Configuration reactors were considered as Continuously Stirred Tank Reactors (CSTR) and therefore were assumed as ideal reactors. The reactant concentrations were considered to be distributed homogenously through the reactors meaning that the reactant concentrations within the reactor are assumed to be equal to the effluent concentrations of the reactors. Rate of accumulation in the reactors were computed for each state variable for defining the mass balance equations of the specific configuration. Cofefficients and stoichiometric parameters defined on process model matrix were multiplied by the process rates of each component for calculating the rate of accumulation in the reactors. Operational processes like constant feed of dissolved oxygen and sludge disposal process for the particulate matter that are going to be wasted were included in the matrix. Computation of sludge disposal was achieved by a sludge retention time input parameter and correction factors for the process rates of denitrifiers were also included to kinetic parameters alongside the coefficients of heterotrophic and autotrophic growth and decay processes. Lastly, hydrolysis rates and coefficients were appended to the model. Calibration and validation of the process model have been achieved by using the data set of an existing WRRF. First 220 days of the data set of 363 days were used for the calibration and last 143 days were used for the validation of the parameter coefficients. Root Mean Square Error (RMSE) and Janus Coefficient methods have been selected for evaluating the precision of model simulation outputs. The most precise predictions in the calibration were achieved for the NH4-N and the NO3-N parameters with Root Mean Square Error values of 1,73 and 2,01, respectively while in the validation phase, the most precise predictions were achieved for the NH4-N and the TKN parameters with Root Mean Square Error values of 0,65 and 0,78, respectively. The least precise predictions were computed for the COD and pCOD parameters on both of the calibration and validation processes with Root Mean Square Error values of 14,41 and 14,14, respectively for the calibration and 5,82 and 7,93, respectively for the validation processes. The verification of the developed software was achieved by implementing the Modified-Ludzack Ettinger model in AQUASIM, an acknowledged simulation software used in environmental science, and comparing the results obtained from AQUASIM and the developed software created in this thesis study. Several simulations were done using the same operational parameters, kinetic and stoichiometric coefficients in each software while changing the parameters and coefficients each time a simulation was performed. Similarly, simulation outputs of each software were compared with simulations having different step sizes like 10-1, 10-2 and 10-3. On all of the simulations mentioned, it was seen that the outputs of the developed software matched the outputs of AQUASIM software. In conclusion, a useful tool to predict the performances of nitrogen removal process schemes for different water quality and treatment requirements was created in this thesis study. Considering a decent automation integration is achieved to the software, the developed software will increase the control of facility operators over the operation of the systems. The need for specific case studies on the modeled configuration will reduce with the efficient use of the software and younger generations of environmental engineers will be provided a better mean of comprehension for the operational, kinetic and stoichiometric parameters and their impacts on the processes.
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ÖgeEnvironmental impacts of Golden Horn dredgings(Graduate School, 2022-02-17)It is possible to pollute water resources with domestic, industrial and surface materials, and in some cases, water resources may begin to fill up. Depending on the water pollution, the sediment can be polluted and even if the water pollution is controlled, it continues to be a source of pollution. One of the most frequently applied methods to control sediment pollution is dredging. This method is also used to prevent water bodies from being filled with materials such as sediment brought in by the water sources that feed them. The management of dredged materials depends on their contamination status. Dredged materials with high pollutant content can be treated by physical, chemical and biological methods or disposed of in specially established facilities for the removal of these materials. During the implementation of the dredging project, it is possible for pollutants leaking from the sediment pore water or present in the fine-grained particles of the sediment to diffuse into the water body, and emissions to water and air depending on the equipment used in the dredging works. It is possible that the environmental impacts of a dredging project that is not implemented carefully will result in adverse impacts. In this study, an evaluation was made on the environmental effects of the dredging works applied both for pollution control and to prevent the Golden Horn from being completely filled. The study includes dredging studies conducted between 2016-2020. The management status of the dredged materials, which were applied at the beginning of the dredging works in the Golden Horn, in the sludge dams established in the quarries, and the dewatering of the dredged materials, which started to be applied later, and their disposal in the sanitary landfill facilities were examined. In addition, the effects of producing bricks with dredged material as an alternative method were investigated. In order to evaluate the environmental impacts of the dredging works, 1 m3 of dredged material was chosen as the functional unit. The system boundaries have been chosen to cover the extraction and transportation of the raw materials to be applied in each process, starting with the removal of the dredged material, its transportation, dewatering, removal and beneficial use. As a result of the life cycle assessment applied, it has been shown that the environmental impact of the disposal method in the sludge dams, which is the first method applied in the Golden Horn, is the most depending on the preparation of the removal area. As a result of the introduction of the landfill method, it has been concluded that although the applied methods require electricity consumption, it is more advantageous than the disposal case in sludge dams. Furthermore, the impacts of brick production with dredged material were compared with traditional clay brick production, and it was concluded that brick production with sediment was an advantageous method.
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ÖgeComparative evaluation of nutrient, land, water and energy requirements of hydroponic vs. conventional agricultural methods: Case study for lettuce, basil, and arugula(Graduate School, 2023-02-07)The rapidly growing world population needs more environmental resources, mainly water and food, to the limit of extinction and defunctionalize traditional solution methods. Available water resources are decreasing day by day, moving to a value below the previously determined rate in researches as 3%. The most powerful reason for this is the increase in the carbon footprint created by industrialization. Global warming, changes in climate lead to insufficient water and food resources for the existing population. The amount of water per capita in year for our country is around 1500 m3, this amount is projected to decrease to 1.100 m3 in 2030. In this direction, efforts to prepare watershed protection action plans including long term conservation programs and measures to protect water resources for all types of use, prevent pollution, improve the quality of contaminated water resources, as well as project works to effectively use the community water resources by reducing losses and leaks in the water supply system have been initiated. Using water resources in our country general directorate of state water works for irrigation datas, other water use datas based on Turk Stat in Turkey as of 2016, 71,3% of the water in agricultural irrigation, 18,4% in industry, 10,3% in drinking and using water was determined. Based on these datas, it is concluded that the amount of agricultural irrigation should be under more controlled, considering the percentage of agricultural water use. In agricultural irrigation, 70% surface, 17% sprinkler, 13% drip irrigation methods are used. New method is used as an another alternative to conventional agricultural food production and also other modern greenhouse food production as the amount of water usage, more efficiently by 95% called "hydroponic farming" technology of food production simultaneously in both climate commitment reduction, reducing production time, while eliminating the problem of transportation into the city in conformance with the installation, reduce your carbon footprint. Dissolved nitrogen (N) and phosphorus (P) are the two main elements that trigger eutrophication. When the elements are above the limit concentrations, it is the result of water pollution and threatens aquatic life. As a result of uncontrolled fertilization in traditional agriculture, these pollutants, which are mixed into the soil release through irrigation water and then into groundwater, threaten the available water resources and the aquatic ecosystem. In the hydroponic vertical farming method, on the other hand, the amount of water used is reduced and fertilizer is used as much as the plant needs, so that there is no uncontrolled release into natural water resources. Comparative evaluation researches of plants grown in a controlled environment have proven that the plant is able to retain more nitrogen and phosphorus. Plants grown in hydroponic agriculture are healthy and nutritious for human health and consumption, while at the same time reducing the higher amount of nitrogen and phosphate in the water. Hydroponic farming systems are agricultural production methods made with only water without using soil. Plants get the minerals they need from the water in a usable form. The effects of technology on agriculture have reached to the inclusion of mechanization in time, then the development of sensor technologies, and finally the automated soilless vertical farming systems in the closed area, where lighting and air conditioning technologies can be realized by replicating nature. Vertical agricultural products, in which almost all leafy greens and some fruits can be grown, are nutritious in terms of content and can be grown in a shorter time. If the plants are grown in these systems, need much less nutrient use, can be carried out indoors and with automation systems, then the compliance of the plants grown with the increasing food requirement and the principle of "food safety and sustainability" is determined. Since the importance of growing indoors will be independent of the effects that may come from outside, chemicals used for pests are not required in these systems. With the development of lighting technologies, sunlight that will operate the photosynthesis mechanism of plants can also be imitated in these systems. The light spectra required by the plant vary at different rates depending on the type of plant. For the most efficient lighting, plants can be tested continuously and the highest yield can be given at any time of the year with full commitment. With advanced technology; automation systems, air conditioning, lighting, dosing, circulation and disinfection processes are monitored by sensors. In addition, the high quality tastes and images of fruits and vegetables grown hydroponically are better quality since the products grown in traditional agriculture are generally used both chemical usage and stress factors such as wind, irregular nutrients distribution and raining. However, in the literature, the nutrient and oil content of plants can be changed without affecting their naturalness by changing the ambient conditions given. Based on studies in literature, it is planned to prepare a thesis that can be examined under the title of Environmental Biotechnology within the scope of the hydroponic system consuming 95% less water compared to traditional agriculture within the principle of sustainability; examining nitrogen, phosphorus and energy consumption; obtaining quantity and plants are grown faster and under the principle of higher yield compared to the climate and arable area problems encountered in traditional agriculture. The aim of the thesis is to realize the reuse of wastewater, higher nitrogen and phosphorus consumption, energy consumption and area usage in the hydroponic system in Gebze Technical University (GTU) Institute of Biotechnology in collaboration with Plant Factory Inc. In the thesis, the prototype installed by Plant Factory Bitki ve Gıda Sistemleri A.Ş. at GTU, Biotechnology Institute; trials of automation will be carried out in which plants will grow in suitable conditions, healthy, higher yield plants. Generally, there are hydroponic studies with lettuce, basil and arugula plants in the literature. The contribution of the study to the literature is a more comprehensive examination of five parameters, in five different experiments, in four different experimental area, with three different leafy greens in a single study. In the study, energy, area, nitrogen, phosphorus and water consumption results were obtained by using three soil experiments and two hydroponic experiments (nutrient film technique, deep water culture) in open field (OF), greenhouse (GH), growth chamber (GC) and container (C) experimental areas that were carried out simultaneously with lettuce, basil and arugula plants. According to the datas obtained from the growing conditions, the nitrogen and phosphorus consumption rates in the hydroponic "Nutrient Film Technique (NFT)" and the "Deep Water Culture (DWC)" experiments are higher than soil agricultural studies. As plants grow, the growing medium only acts as a carrier for nutrients. For this reason, the environment of plants in traditional agriculture is soil, while hydroponic systems' is water, so plants take nutrients and transport them to tissues faster. In this case, because of providing homogeneity in water faster; homogeneous growth of plants is higher than soil agriculture by the way. Hydroponic systems are supportive alternative to traditional agriculture for efficient use of water in addition to efficient nitrogen and phosphorus consumptions. In the study conducted with NFT, it was observed that the water consumption rates were the lowest was more higher than others followed by DWC. High area use efficiency can be achieved successfully with the NFT hydroponic system in plant cultivation followed by DWC. In addition to that, another reason for the different responses of grown plants to different environmental conditions is the positive effect of lighting technology on plant growth. In addition, the importance of climatic conditions for the plant is as valuable as the lighting technology. As a result of the temperature and humidity conditions being adjusted where the plant does show required stress conditions to balance both the root and upper parts of the plant under the effect of transpiration and photosynthesis. The amount of energy consumption, which is another parameter obtained from datas, calculated as per gram dry leaf weight, is from low to high, respectively; in soil-based experiments as OF, GH, GC experimental areas; in hydroponic studies, NFT, DWC systems. NFT consumes less energy than the DWC hydroponic system but more than greenhouse production. In today's conditions, energy is provided from fossil sources. For this reason, although the carbon emission rate due to transportation is much less than traditional agriculture with its establishment in city centers, the energy used during production, especially due to lighting technologies, is quite high. Renewable technologies should be used to prevent energy-related carbon emissions. Solar, geothermal, wave, wind, biomass, hydroelectric, hydrogen energies are among the renewable energy sources that can be used. Considering the advantages and disadvantages, indoor hydroponic systems in green leafy plant cultivation is considered as an alternative method to support soil agricultural methods, both in terms of water, area, nitrogen-phosphorus use efficiency and the yield per square meter area.
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ÖgeDetermination of biogas potential of banana harvestingwaste and environmental life cycle assessment of utilizingstem waste for banana production in greenhouses in Türkiye(Graduate School, 2022-09-26)In Türkiye, 548,323 tons of banana fruit were produced in 2019. Banana fruit mainly grows in the Mediterranean Region due to the favorable temperature conditions. The year-long average temperature, humidity, and specifications of the soil are the parameters that make this region preferable for banana production. However, the environmental conditions in the Mediterranean Region have disadvantages when the region is compared with the countries that are the motherland of bananas such as India, Uganda, Ecuador, and Brazil. The ideal growing temperature for bananas is 27° C. In the case of a production environment at this temperature, an average of 100 kg of fruit can be collected from a plant for each harvest, although it varies according to the type of banana plant. It is not possible to capture this temperature regime during the year in Türkiye. For this reason, 77% of the current banana production is made in greenhouse areas. Greenhouse areas are production areas designed to keep the indoor temperature as high as possible, especially in winter. However, with existing methods, producers cannot increase the indoor temperature above 15 ° C in winter. This situation leads to the 40-50 kg range of production yield in each harvest per tree in Türkiye. Although this amount, which was half the current yield in the previous periods, is accepted; when the increasing banana consumption is considered, producers have tried various methods to increase this yield even more. However, most of them have failed. One method that has been tried frequently has been to use a heat source to increase the temperature of the covered areas. Some producers have installed wood, coal, and even natural gas stoves in greenhouses, also known as greenhouses, and tried to heat the interior in this way. The average size of the greenhouses densely located in Mersin and Alanya regions is 3 decares; In greenhouses covering these and larger areas, heating by setting up a stove has not been an effective method since it could not heat the entire area homogeneously. The most effective method for increasing the yield of banana production in Türkiye is to spray the groundwater into the greenhouse to improve the indoor temperature to a higher level than the ambient temperature. In Alanya, where the average air temperature is 11.8 °C in winter, groundwater temperatures are around 15 °C. Therefore, the usage of groundwater by spraying is an effective method of heating the greenhouses during the winter period. While some producers feed the groundwater directly into the greenhouses, some producers use the boiler systems they have installed to heat the groundwater and give it into the greenhouse. Fossil and nonrenewable energy sources are widely used in the heating process. This study, aims to evaluate the wastes generated during banana production and harvest and to measure the environmental effects of this method to handle the banana production process with a more circular approach, which will be an alternative to fossil fuels. The banana harvest takes place approximately 9 months after the plant sprouts. Depending on the type of banana plant, the plant's height could reach 8-10 meters during that time. The main planted banana plant species in Türkiye are Azman, Dwarf Cavendish, and Grande Naina can grow up to 6 to 8 meters. When the fruit harvest is completed, the strongest sprout is left from the newborn roots of the banana plant, and the whole plant is cut and left as waste. During the production of every 1 kg of banana fruit, 4 kg of harvest waste is generated. Banana harvest waste consists of leaves, stems, roots, root stems, flowers, and raw fruits. These completely organic wastes contain a high yield of carbon, nitrogen, phosphorus, and potassium. Currently, some producers leave these wastes in greenhouses and wait for the rich nutrient content to return to the soil. Although leaving these wastes to decompose in an uncontrolled way has a positive effect on nutrient recovery, generally, the application of a non-homogeneously distributed dose to a certain area has a negative effect. In addition, a disease that occurs in harvested plants can pass into the soil as a result of decomposition and damage healthy or newly budded plants. The banana harvest waste is quite suitable for energy and nutrient recovery by anaerobic digestion method when all the mentioned effects and properties are evaluated. In the anaerobic digestion method, banana harvest wastes are digested in a controlled reactor in the absence of oxygen at constant temperature and pH. During the digestion process, various bacteria consume organic matter and pathogens in the harvest waste and produce biogas, the content of it mostly methane (CH4) and carbon dioxide (CO2) gases. The produced biogas has a flammable feature due to the CH4 gas content and thus can be used as a renewable fuel. This study was carried out in two stages. In the first stage, the biogas potential of banana harvesting waste that occurred in Türkiye was measured in a pilot-scale anaerobic biogas reactor built in Lüleburgaz, Kırklareli. Thus, the potential of banana waste as a renewable source was measured for the greenhouse production areas which use groundwater as the heating source. However, due to different reasons (logistics, technical problems, etc.), the reactor could only be operated for 30 days, and the system could not reach a steady state during this time. However, the results and experiences obtained, albeit for a short time, are given to shed light on future studies. It is not recommended that these results be used for design purposes as the steady state is not reached. The reactor design was completed based on the results of the characterization of banana harvesting waste samples collected from southern Türkiye. The reactor volume is calculated as 10 m3. Anaerobic digestion was carried out in mesophilic conditions for 30 days. The results collected in the 30-day experiment were verified by comparison with literature data. Then, parameters in the design of the pilot scale reactor and biogas production quantities were used as inputs in the life cycle assessment. In the second stage of the thesis, the life cycle environmental impacts of banana production and then its supply to the end user in Türkiye were investigated. The low groundwater temperatures in Türkiye inhibit the yield of banana trees in Türkiye and literature suggests that it is possible to double the yield of a single tree by increasing the irrigation water temperature to 27 °C. Hence, three different scenarios were studied. The first scenario, also known as the business as usual case was considered; in the second scenario heating the irrigation water by using natural gas was studied, and in the third scenario heating the irrigation water by using biogas produced on-site via the anaerobic digestion of banana stem waste was analyzed. The functional unit was chosen as 2 tons of bananas produced throughout the lifetime of the biogas production system. CCaLC2TM was used as software, and CML2001 methodology was used. A cradle-to-grave approach was employed. The production processes were modeled based on real-life data acquired from a real greenhouse in Türkiye. Six impacts (global warming potential, acidification potential, eutrophication potential, photochemical oxidant creation potential, ozone layer depletion potential, and human toxicity potential) were calculated. Results show that four of the six impacts decreased when biogas was used, suggesting that this practice has the potential to reduce the environmental footprint of banana production. The results were found to be in good agreement with the values reported in the literature. It was concluded that to reduce the environmental footprint of banana production, utilizing stem waste instead of the conventional practice of burning is essential, and special emphasis should be given to treating or utilizing the bioreactor digestate to further reduce the environmental footprint.