Mikrokirleticilerin öz ozonlanması ve biyolojik arıtılabilirliği

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Tarih
1997
Yazarlar
Ateş, Arzu
Süreli Yayın başlığı
Süreli Yayın ISSN
Cilt Başlığı
Yayınevi
Fen Bilimleri Enstitüsü
Institute of Science and Technology
Özet
Bu çalışmada, mikrokirleticilerin inhibisyon etkisini azaltmak amacıyla ozonla oksidasyonu ve ozonlanmış numunenin biyolojik arıtılabilirliği araştırılmıştır. Bu amaçla laboratuarda hazırlan ksilen ve siklohekzanon numunesinin ozonla oksidasyonu yapılmıştır. Ozonlama, atıksuyu biyolojik arıtmaya hazırlamak için ön arıtma adımı olarak uygulanmıştır. Ozonlanmış numunenin laboratuarda kurulan doldur-boşalt tipi kesikli aktif çamur reaktörlerinde biyolojik artılabilirliği incelenmiştir. Ozonlamanın biyolojik arıtıma olan etkisini belirlemek amacıyla ozonlanmış (şahit) numuneninde biyolojik arıtılabilirliği araştırılmıştır. Sentetik numunelerin (ozonlanmış ve ozonlanmamış) uçuculukları da biyokütle içermeyen şahit reaktörlerde test edilmiştir. Birinci bölümde, çalışmanın anlam ve önemi kısmında, konuya esas olan mikrokirleticilerin anlam ve öneminden kısaca bahsedilmiş çalışmanın amaç ve kapsamı özetlenmiştir. İkinci bölümde, mikrokirletici kavramının ortaya çıkışı ve gelişimi, mikrokirletici zararlı atık ayrımı incelenmiştir. Ayrıca bu bölümde mikrokirleticilerin zararlılık derecesini belirlemede kullanılan THP sistemi, mikrokirleticilerin kontrol yöntemleri ve arıtım mekanizmaları verilmiştir. Üçüncü bölüm, kesikli ve sürekli sistemlerde ozonla kimyasal oksidasyon için gerekli deney düzeneği ve ekipmanlarının detaylı olarak verildiği bir bölümdür. Ayrıca bu sistemlere ait analitik hesaplama yöntemleri de yine bu bölümde yer almaktadır. Dördüncü bölüm, deneysel çakışmayı içermektedir. Laboratuarda hazırlanan sentetik numunenin ozonla oksidasyonu, ozonlanmış ve ozonlanmamış numunelerin biyolojik arıtılabilirlikleri ve numunelerin uçuculuk ile ilgili yapılan deneyler ve sonuçları tablo ve grafikler halinde verilmiştir. Sentetik numune ile yapılan deneylerden elde edilen sonuçlar ve öneriler ise son bölüm olan beşinci bölümde yer almaktadır.
Water pollution by defined chemical subtonics has a long history; classical examples in the past are phenols and pyridines in effluents from coke oven plants. Since mid 1960 s, however people have become aware that some substances, for instance mercury derivatives, DDT and PCB s, can persist in the environment, enter and become enriched in food chains and reach toxic levels in certain organisms. This recognition of toxicity has been a driving force behind the development towards stricter and better environmental management. In this study; chemical oxidation with ozone is applied for synthetic samples under laboratory conditions following long-term literature studies. Ozonation is used for pretreatment purposed so as to reduce COD removal efficiency and prepare for biological treatment. Preozonation was investigated for its effects on the biodegradability of cyclohexanon and xylene in activated sludge systems. The volatility of cyclohexanon and xylene were investigated in a reactor with aeration without biomass. In the preceding section that contain aim and scope of the parts, the importance, definition and treatment of specific water pollutants are briefly given and aim and scope of the study are summarized. In the second section environmental problems raised by specific water pollutants are described and development of specific water pollutants concern is given. Specific pollutants caused many scourges in the past and are still causing at present. During the time passed many number of pollution, health problems and death cases are reported and substantial is observed because of disregarding. Studies sparked off by the recognition that contaminants from human activities are ubiquitous in the environment and that many of these substances are potentially hazardous to man' s environment. There is undoubted concern because. information on the type and quantity of substances discharged to the environment is complete. with a few notable exceptions, the information on environmentally significant properties, particularly stability, affinity for living organisms and short-term and long-term toxicity is incomplete and scare VIII . a number of these compounds are not adequately removed by present treatment of waste water or potable water, and for other substances there is insufficient information. available control instruments-legal, administrative and other, and their implementation - do not always cover all situations where the discharge of specific pollutants should be controlled. The specific pollutants concept was used to emphasize the difference between identifiable chemical substances. Because of the complexity of the problem, it was not judged possible to carry out a complete assessment on specific pollutants control. Also in this section are defined the difference between hazardous waste and specific pollutants, and the system of THP, and are given sources of specific water pollutants. The experimental procedures and equipments needed for chemical oxidation with ozone, for both batch and continuous systems are examined in the third section with details. In the fourth section, the experimental methods are told. The aim of the experiments are carry out the oxidation with ozone processes for synthetic wastewater samples, that contain cyclohexanon and xylene, that are prepared in the laboratory conditions so as to reduce the efficiencies of COD removal The chemical structures and characteristics of these substance are briefly given. Also in this section biological treatment are given. Results indicate that preozonation could either promote or retard the biodegradability, depending primarily on whether or not the sludge used in the subsequent biological system had been acclimated before hand. Some of compounds have been reported to be extremely resistant to biodegradation, either in nature or in the treatment systems receiving the waste streams. Therefor to improve the biodegradability of these specific compounds, the possible methods usually include these by which the biological systems can be acclimated well enough to decompose effectively the influent components, or, these by which the originally resistant compounds can be converted into more easily degradable forms prior to entering the biological systems. In this study, batch type activated sludge units were employed to serve as the biological treatment systems and the process of preozonation was used on the other hand to convert the chemical structure of the cyclohexanon and xylene compounds. On of the purpose of this study was to compare two methods with or without the ozone pretreatment. The efficiencies of the pretreatment were measured in terms of the removal of the cyclohexanon and xylene compounds themselves and the COD contents as the gross organic indicator. The dichromate method was used for the COD analysis. IX Various units of the batch-type activated sludge systems were used to receive the feed from different cyclohexanon and xylene solutions with or without the ozone pretreatment. The activated sludge collected from a reactor was acclimated gradually to the increasing feed of phenolic compounds with the original carbon source from glucose being finally replaced. Experimental study plan is presented in Table 1. Ozonation is applied through a semi-batch ozonation equipment. COD test are run for the monitoring of synthetic samples following ozonation. For ozone gas measurement, iodometric ozone measurement and comparametric ozone measurement are applied. For synthetic sample theoretical oxygen requirement values are calculated and compared with COD values. Table 1 Experimental Study Plan The sample experiment results that are obtained different ozonation times are given as graphics in Figure 1. For synthetic sample values for applied ozone, discharged ozone gas, efficiency of ozone that is consumed for wastewater, concentration of ozone that is consumed for wastewater and ozone dosage are estimated. 2D O I ? I ? I I 15 30 60 80 123 CtaT£tiOTTime(nnin) -? - Samplel (80 nin CEonaticn) ?Samrje2 - A - Sample 3 (120nniri (120rrin cecnaticn) czcnaticn) Figure 1 Obtained COD Values of Synthetic That Are Prepared With Xylene and Cyclohexanon After 80 min. and 120 min. Experimental study results for synthetic sample with or without ozonation are given in Table 2. In the fifth section results of the experiments are given and some proposals are brought in. These proposal are named below. Especially for cases when treatment of micropollutants and hazardous wastes in the main goal, preozonation for the substances that may inhibit the treatment can be applied. It has been observed that application of ozone for any other purpose than preozonation may not be successful. In other words, oxidation of ozone in such wastes is not eligible or not economic. By the application of preozonation, detoxification purposes can be achieved for both individual substances and for cinerjestically effected mixed wastes. In this case estimation of inhibition with biological treatment of wastes that have been preozoned and detoxified should be accomplished. In the some manner, inhibition of ozone in biological treatment must be determined. For the substances which volatility is very high as cyclohexanon and xylene can be proposal appropriate treatment system is aeration (air stripping) ozonation and biological treatment
Açıklama
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1997
Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 1997
Anahtar kelimeler
Biyolojik arıtma, Ksilen, Mikrokirleticiler, Oksitlenme, Ozon, Siklohekzanon, İnhibisyon, Biological treatment, Xylene, Micropollutants, Oxidation, Ozone, Cyclohexanone, Inhibition
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