Kimyasal oksijen ihtiyacı deşarj limitlerinin sağlanmasında inert ve mikrobiyal ürünlerin rolü: Organize sanayi bölgesi örneği
The role of inert and microbial products in meeting discharge limits of chemical oxygen demand: Case of organized industrial zone
Yazar: AYÇA KILIÇARPA
Danışman: PROF. DR. HAYRETTİN GÜÇLÜ İNSEL
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Çevre Mühendisliği Ana Bilim Dalı / Çevre Bilimleri, Mühendisliği ve Yönetimi Bilim Dalı
Derece: Yüksek Lisans, 2022
Konu: Çevre Mühendisliği = Environmental Engineering
Dizin: Atık su arıtma sistemleri = Waste water treatment systems ; KOİ = COD ; Kimya endüstrisi = Chemical industry ; Organize sanayi bölgeleri = Organized industrial zones

Özet:
Atıksularda biyolojik olarak arıtılabilirlik özelliği açısından oranları çok geniş aralıkta değişebilen organik maddeler bulunmaktadır. Endüstriyel atıksularda, atıksu karakterizasyonunun doğru olarak yapılmaması, diğer bir deyişle organik madde bileşenlerinin doğru bir şekilde saptanmaması, arıtılabilirlik deneylerinin sonuçlarının yanlış yorumlanmasına ve deşarj kriterlerinin sağlanmasında problemlere yol açabileceğinden büyük önem arz etmektedir.
Endüstriyel atıksu arıtma tesisi çıkış atıksuyundaki Kimyasal Oksijen İhtiyacı (KOİ) parametresi deşarj standartlarının sağlanması açısından önemli bir yere sahiptir. Sadece toplam KOİ veya çözünmüş KOİ'nin tespit edilmesi yeterli olmayabilir. Çıkış atıksuyunda organik maddelerin biyolojik olarak parçalanabilirliğinin tespitinde KOİ'nin biyolojik olarak ayrışabilen kısmının ve inert KOİ bileşenlerinin tespit edilmesi gerekmektedir.
Çevre biyoteknoloji alanındaki son gelişmelere ve modelleme alanındaki ilerlemeler sayesinde, tesislerin tasarım aşamasında arıtma verimlerinin hesaplanmasında özellikle inert ve yavaş ayrışan organik madde bileşenlerinin miktarlarının ve toplam organik maddeye oranının doğru belirlenmesi, kolay ayrışabilir organik madde kinetiğinden daha önemli bir hale gelmiştir. Bu gelişmeler modelleme anlayışına da yansımış ve arıtma kinetiğinin substrat ve biyokütleden oluşan iki bileşenli matematik modeller ile ifade edilmesi son yıllarda geçerliliğini yitirmiş ve günümüzde çok bileşenli modelleme yaklaşımları uygulanmaya başlamıştır. Bu yaklaşıma göre atıksu karakterizasyonunun biyolojik olarak ayrışamayan, yavaş ayrışan ve hızlı ayrışan organik madde bileşenlerini içerecek şekilde yapılması ve tasarımda kullanılacak olan stokiyometrik ve kinetik parametrelerin doğru belirlenmesi gerekmektedir.
Bu çalışmada kimya kategorisinde yeralan bir organize sanayi bölgesi (OSB) atıksu arıtma tesisinin giriş atıksu örneği üzerinde çok bileşenli modellemeye imkan tanıyacak karakterizasyon yaklaşımı içinde, konvansiyonel atıksu karakterizasyonunun belirlenmesini, inert, yavaş ve hızlı ayrışan organik madde bileşenlerinin, kinetik ve stokiyometrik katsayıların deneysel yöntemler ile saptanmasını ve elde edilen bulgular yardımı ile karbon giderimine yönelik bilgisayar destekli modelleme çalışmalarını içermektedir. Ayrıca, elde edilen veriler yardımıyla tabi olunan deşarj limitlerinin sağlanmasında çözünmüş inert ve mikrobiyal ürün oluşumunun etkisinin değerlendirilmesini de kapsamaktadır. Mevcut atıksu arıtma tesisine 182 – 1761 m3/gün aralığında debi gelmekte olup ortalama 1014 m3/gün değerini almıştır. Endüstriyel atıksuların biyolojik olarak arıtılabilirliğinde önemli bir husus reaksiyon sonunda geriye kalan inert organik madde miktarıdır. İncelenen OSB atıksularında biyolojik arıtma sonrasında geriye kalan çözünmüş (arıtılamayan) inert organik madde konsantrasyonu %6-8 arasındadır.
Bu tez kapsamında; birinci bölümde konunun önemi ve amacı hakkında bilgi verilerek yapılan çalışmanın kapsamı anlatılmıştır. İkinci bölümde konu özelinde literatürde yer alan bilgiler özetlenirken üçüncü bölümde ise çalışmaya konu mevcut endüstrinin tanıtımına ve materyal/metod bilgilerine yer verilmiştir. Dördüncü bölümde, deneysel ve modelleme çalışmalarının değerlendirilmesi yapılmış ve son olarak, beşinci bölümde genel sonuçlar ve öneriler sunulmuştur.

Abstract:
The role of chemicals, which are among the important components of modern life due to their contribution to the standard of living, is critical in almost every field, from food to clean water supply, clothing and shelter, health and transportation, semiconductor circuits and technology.
The chemical industry is a sector that uses natural or synthetic raw materials to produce and exchange to meet the needs of other manufacturing sectors and consumers. In the chemical industry, pesticides and fertilizers for farmers, pharmaceuticals for the health sector, synthetic dyes and fibers for the textile industry, soaps and beauty aids for the cosmetics industry, synthetic sweeteners and flavors for the food industry, plastics for the packaging industry, chemicals and artificial for the automobile industry rubber is produced. Chemical industry provides input to all sectors of automotive, information and communication technologies, machinery, investment and consumer goods, which will be effective in global production and trade in the coming years.
In the late 19th century, at the peak of the industrial revolution, there were rapid developments in the amount of production and various chemicals produced in the chemical industry. Today, the chemical industry has a wide range of products.
In Turkey, chemical industry mainly consists of facilities where various chemical raw materials and consumption products such as petrochemicals, soap, detergent, fertilizer, medicine, paint-varnish, synthetic fiber, soda are produced.
Wastewater from the chemical industry is generally highly concentrated with organic and inorganic pollutants and may contain high amounts of toxic pollutants. Chemical industrial wastewater usually contains varying concentrations of organic and inorganic substances. Wastewaters generally contain organic materials that vary in amount in a wide range in terms of biologically treatability. Especially in industrial wastewaters, not performing wastewater characterization correctly, in other words, wrong determination of substrate components, is of great importance as it will lead to misinterpretation of biological treatability results.
In the chemical industry, treatment methods can be determined according to the variability in wastewater, wastewater discharge permits and working conditions, etc. Many different processes can be used in the treatment of wastewater originating from the chemical industry.
In order to remove the pollutants in the wastewater, primary, secondary and advanced treatment methods are used according to the wastewater character. Primary treatment includes physical treatment units that involve the removal of floating and settleable matter in wastewater. Secondary treatment includes biological and/or chemical treatment units used for the removal of organic substances. In addition to these processes, advanced treatment includes processes used to remove pollutants that are not removed in secondary treatment.
The most important topic in multi-component modeling studies of activated sludge systems is the determination of wastewater characterization. In terms of modeling studies, the amount of organic matter should be determined by the COD parameter in order to establish the electron acceptor balance between the substrate, biomass and dissolved oxygen.
The Chemical Oxygen Demand (COD) parameter in the effluent of the industrial wastewater treatment plant has an important place in terms of ensuring the discharge standards. Detection of total COD or dissolved COD alone may not be sufficient. In the determination of the biodegradability of organic substances in the effluent, the biodegradable part of the COD and the inert COD components should be determined.
Total COD of wastewater is classified into two separate classes based on its biodegradation characteristics: total biodegradable COD and non-biodegradable or inert COD. The inert COD fraction are subdivided into two components, soluble inert COD and particulate inert COD. Soluble inert COD constitutes the most important fraction of organic matter in the effluent of the treatment plant, since it is discharged with wastewater discharge without undergoing any biochemical reaction in the activated sludge system. Particular inert COD accumulates in the system depending on the age of the sludge, as it is removed from the system only by removing excess sludge, but also affects the amount of sludge to be removed from the system.
Particulate COD has different components in the effluent than raw wastewater. Except for the particulate inert COD present in the raw wastewater that is retained and accumulated by the sludge, it is observed in the effluent of active heterotrophic biomass using biodegradable COD as substrate. At the same time, the part of the slowly hydrolyzable organic matter that cannot be removed according to the sludge age can be observed in the effluent. The fourth component of total particulate COD is the inert particulate COD, which is formed as a result of metabolic activities during the degradation of biomass.
According to recent conceptual developments in the field of biotechnology, the determination of the amount of inert and slowly biodegradable substrate components has become more important than the kinetics of the readily degradable substrate in predicting treatment plant efficiencies. These developments are also reflected in the understanding of modeling. Expressing treatment kinetics with two-component mathematical models consisting of substrate and biomass has lost its validity in recent years. Today, new multi-component modeling approaches are applied. According to the new approach, wastewater characterization should include inert, slowly decomposing and rapid biodegradable substrate components and stoichiometric and kinetic parameters to be used in the design should be determined correctly.
Organizations located in the organized industrial zone are engaged in production activities in different fields such as paint production, plasticizer production, pharmaceutical industry, building materials, polyester production, zinc oxide production.
The current wastewater treatment plant consists of one chemical treatment system and three sequencing batch biological reactors. The field of activity of the wastewater treatment plant includes the treatment of all domestic and industrial wastewater that will originate from the organized industrial zone and discharge into the receiving body, and the sludge to be produced after this treatment is dewatered and sent to licensed waste disposal companies.
The experimental setup prepared for the determination of inert COD components consists of two batch reactors. The first was fed with filtered wastewater and the second with glucose solution with COD equivalent to filtered wastewater. Both reactors was set up with 20 mg/L VSS biomass. The reactors were operated for a sufficiently long time with ventilation until the COD values stabilized (30-50 days), and the experiments were carried out at a constant room temperature of 22±1ºC and pH 7.0-8.0. By evaluating the final COD results obtained from each operated reactor, COD component and the stoichiometric coefficients of the metabolic products formed can be calculated.
In the context of this study; total COD analyzes were made with wastewater of the balancing tank, chemical treatment plant outlet and treated wastewater. Modeling studies were carried out using Oxygen Consumption Rate profiles and heterotrophic kinetic coefficients were determined for 22°C conditions.
In this context, the aim of the thesis is to determine the conventional wastewater characterization, to determine the inert, slowly and rapidly biodegradable organic matter components, kinetic and stoichiometric coefficients experimentally, within the characterization approach that will allow multi-component modeling on the inlet wastewater sample of an organized industrial zone wastewater treatment plant in the chemistry category. It contains computer aided modeling studies for carbon removal with the help of the obtained findings. It also covers the evaluation of the effect of soluble inert and microbial product formation on providing the discharge limits to which it is subject, with the help of the obtained data. The current wastewater treatment plant receives a flow rate of 182 – 1761 m3/day, with an average value of 1014 m3/day. An important issue in the biological treatment of industrial wastewater is the amount of inert (undegradable) organic matter remaining at the end of the biological reaction. The concentration of soluble inert organic matter after biological treatment in the investigated organized industrial zone wastewater is between 6-8%.
In the examined wastewater treatment plant balancing inlet wastewater sample, the dissolved inert COD component constitutes 2.84-3.93% of the total COD value, and the total dissolved inert COD components at the outlet constitute 5.6-7.6% of the total inlet COD value. It was concluded that 96% of the wastewater generated from the organized industrial zone is biodegradable. It was observed that the easily biodegradable fraction of COD constituted 19% and 51% of the total COD. The rapidly hydrolysable COD component was determined as the largest COD fraction representing 28% and 58% of the total COD, while the same rate was determined as 17% and 19% for slowly hydrolyzable COD.
Within the scope of this thesis; In the first part, the scope of the study was explained by giving information about the importance and purpose of the subject. In the second part, the information in the literature is summarized, and in the third part, the introduction of the existing industry and material/methods were given. In the fourth part, experimental and modeling studies were given in detail. Finally, general conclusion and suggestion were presented in the fifth part.