Gıda Endüstrisi Kaynaklı Koku Emisyonlarının Kontrol Stratejilerinin Geliştirilmesi

Abstract

Koku emisyonlarını oluşturan moleküller günümüzde önemli bir hava kirletici parametre konumundadır. Bu emisyonlar insanları rahatsız edici özellikleri yanında sağlık üzerinde de zararlı etkileri olan bileşikleri içermektedir. Koku oluşumunda inorganik ve organik yapıda pek çok kimyasal bileşik yer almaktadır. Koku oluşumunda yer alan organik bileşiklerin önemli bir kısmı atmosferde ozon sentezini tetiklemede ve oksidasyon ürünleri ile sera gazlarına katkıda bulunmaktadır. Koku emisyonları endüstriyel prosesler, depolama ve transfer işlemleri, atık bertaraf prosesleri, durgun su kütleleri, doğal çürüme olayları gibi birçok kaynak tarafından oluşturulmaktadır. Özellikle ülkemizde 01 Ocak 2012 tarihi itibarı ile yürürlüğe giren “Kokuya Sebep Olan Emisyonlarin Kontrolü Yönetmeliği (KSOEKY)” ile koku emisyonlarına neden olan endüstriyel tesislerin çevrelerinde koku rahatsızlığı oluşturup oluşturmadığının belirlenmesi ve yasal limitlerin aşılması halinde de uygun kontrol sistemleri ile arıtılması mecburiyeti getirilmiştir. Koku probleminin oluştuğu bölgelerde kokulu kirleticilerin zamana ve mekana bağlı kalınarak uzun süreli ölçümleri deneysel zorluklar ve yüksek maliyetlerinden ötürü her zaman uygun olmamaktadır. Bu problemleri minimize etmek ve problemin efektif olarak tespitine yönelik olarak matematik modeller hava kalitesi yönetiminde emisyonların belirlenmesi aşamasında kullanılmaktadır. Bu çalışma kapsamında maya endüstrisi kaynaklı koku emisyonlarının neden olduğu koku problemlerinin hava kalitesi modeli AERMOD ile yer seviyesindeki dağılımı, değişik atmosferik koşullar çerçevesinde yapılmıştır. Çalışmanın ilk aşamasında inceleme yapılacak alanda bulunan koku emisyonu kaynakları tespit edilip karakterleri ve koku oluşturma eşik seviyeleri literatürdeki verilerle desteklenerek belirlenmiştir. Kaynak özellikleri belirlenen bölgenin topoğrafik şartları ve o bölgenin meteorolojik özelliklerini temsil eden yıllık meteorolojik verilerini içeren meteorolojik veri dosyası model programına eklenerek değişik senaryolarda model çalışmaları yapılmıştır. Model çıktı dosyaları analiz edilerek koku probleminin oluşabileceği noktalar belirlenmiştir. Koku probleminin oluştuğu bölgelerin hangi faktörlerden etkilendiği ve koku problemine maruz kaldığı belirlenmiştir. Koku rahatsızlığının yoğun olduğu bölgelerdeki koku probleminin giderilmesine yönelik olarak maya endüstrisi fermantasyon prosesinde uygulanması gereken önlemlerin neler olduğu ve kokulu gaz içerisinde bulunan uçucu organik maddelerin uygun ve efektif bir biçiminde arıtımını sağlayan metotlar tespit edilerek ilgili öngörüler ve nedenleri değişik senaryo uygulamaları için belirlenmiştir.

Nowadays odor emissions are considered as an important air pollution parameters. These emissions have an irritant effect on human senses, but also include toxic materials on the human health.In fact, very little information is avaible on the impact of odor on human health( e.g., the smell of hydrogen sulfide and its lethality to humans) Many inorganic and organic chemical compounds take part in odor structure.There are several problems to that approach, the toxicity of most chemicals, even those with high production volumes, is not known, and frequently the chemical composition of materials resulting from complex industrial processes is unidentified. Organic compounds which take part in odor formation trigger ozone synthesis in the atmosphere and contribute to the greenhouse gases with the oxidation products. The most important odor emission sources are industrial processes, storage and transfer operations, waste disposal processes and natural decay events. Especially today, industrial facilities caused the odor emissions must be controlled to provide the legal limits by the regulation Regulation on Control of emissions that contribute to odor (KSOEKY) , which came into force as of January 1, 2012 . If the legal limits which determined by this regulation excess, the industry is obligated to treat the emissions by proper control systems. It is asked for the control gase emissions of industrial facilities by Industrial Air Pollution Control Regulation (SKHKKY). Infrastucture systems for odorous gases treatment are inadequate in our country and limited applications is made substantially as turn key facilitiy or it is been increased by request for consultancy service. It is required to support this subject area in manner local technology and academical research applications should be extend. Within this project processes, that cause odor emission from food industries will be analyzed in representive example for each industry and odour emissions for both industries will be assessed within Regulation on Control of emissions that contribute to odor and Industrial Air Pollution Control Regulation regulations. In the area of odour problem, it is difficult to make long-term measurements of adherence to time and space because of experimental difficulties and high costs are not always appropriate. Odor measurements take long times and laboratory costs are too much. For a result of this situatin the most effective way for minimizing these problems, to use of mathematical dispersion models for determining the stage of emissions in the management of air quality. Comparing the odor measurements, mathematical dispersion models take short times and low cost capitals. Within this project AERMOD dispersion model is used to make short term measurements for air and odor pollution controls. AERMOD atmospheric dispersion modeling system is an integrated system that includes three modules. AERMOD is a steady-state dispersion model designed for short-range (upto 50 kilometers) dispersion of air emissions from stationary industrial sources. Within this project yeast fermentation process and their odorous emissions are analyzed in 10*10 km area range. AERMOD consist of three modules and one of them is AERMET module. AERMET is a meteorological data preprocessor that accepts surface meteorological data, upper air soundings, and optionally, data from on-site instrument towers. It then calculates atmospheric parameters needed by the dispersion model, such as atmospheric turbulence characteristics, mixing heights, friction velocity, Monin-Obukov length and surface heat flux. Meteorological datas are divided to the two parts. One part is for surface meteorological datas and other part is high atmosphere datas. AERMOD combines to kind of datas and convert them to the one file. Within this project meteorological datas has taken from Izmit meteorological station, because of representing the regions meteorological characteristic and most appropriate year was selected for representing meteological situations. Another module of AERMOD is a terrain preprocessor (AERMAP) whose main purpose is to provide a physical relationship between terrain features and the behavior of air pollution plumes. It generates location and height data for each receptor location. It also provides information that allows the dispersion model to simulate the effects of air flowing over hills or splitting to flow around hills. To find the exact coordinates for investigation area “Google Earth” program is used. After getting coordinates for investigation area, SRTM ( Shuttle Radar Topography Mission) map selected and added to the system.In this manner AERMAP can read all of the evelations for each reseptor and it shows us exact terrain profiles. AERMOD also includes PRIME (Plume Rise Model Enhancements) which is an algorithm for modeling the effects of downwash created by the pollution plume flowing over nearby buildings. After getting all data modules for AERMOD atmospheric dispersion model, model run succesfully and as a result of AERMOD terrains that have affected from odorous gaseous emissions, are determined. Model run for the most worse senarios and determine terrains for the odour problem. As a result of yeast fermentation processes number of factors affect the emissions of compounds from food industry operations. Most of the substances emitted are the products of microbial prosesses and in most cases it is the microbial environment that will determine which substances are generated and at what rate. During the degradation of organic matter in yeast fermentation process under anaerobic conditions volatile organic compounds (VOC) like ethanol and acetaldehyde are relased to the ambient air and they are primary sources for the odor problem and if the concentration of this compunds excees the threeshold level, odor problems occur in the ambient air. Within this project AERMOD model has run for alternative scenarios and the datas are analyzed for all scenarios. Solution alternatives for each scenario are investigated. After analyzing the results of model for odorous emissions treatment alternatives are discussed like absorption, biological treatment and biofilm for these kind of pollutants will be investigated. Depending on construction and operation cost, biological odour treatment systems , physico-chemical oxidation / thermal oxidation processes are analyzed. In a conclusion of this project odorous emissions from yeast fermantation process are determined in the ambient air for ethanol and acetaldehyde with using mathematical air dispersion model AERMOD and three alternative scenarios for the worst conditions are investigated and as a result of defined terrains that is affected from odor problems from yeast fermantation processes. Pilot receptors are selected to identify odorous emissions in the near of living spaces and the datas on this points are analyzed. The best avaible treatment technology for the odorous emissions are to be suggested to solve the odor problem and as a result of this study biofilters and bioscrubbers are suggested due to their low operational and construction cost and their environmental friendly technologies.