Rekalsitrant azo bileşiklerin anaerobik/Aerobik ardışık sistemlerde giderimi
Yükleniyor...
Dosyalar
Tarih
2002
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
TÜBİTAK
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Azo boyaları yapılarında bir veya daha fazla azo (N=N) bağı içeren renklendirici maddelerdir. Azo boyaları tekstil, plastik, kağıt, mineral yağ, gıda ve kozmetik sanayiide renklendirici olarak kullanılırlar. Endüstrilerde kullanılan boyalar içinde %60-70'lik kısmı teşkil ederler. Azo boyaları en çok tekstil boyamada kullanılırlar. Renkleri, biyolojik olarak zor ayrışmaları, kalıcı olmaları, ve canlılar üzerinde potansiyel toksik etkileri nedeni ile atıksu arıtımında problem olarak görülürler. Azo boyaları aşırı elektron alma eğilimlerinde oldukları için klasik aerobik proseslerle parçalanamakta ve anaerobik proseslere ihtiyaç duyulmaktadır. Oluşan ara ürünler (aromatik aminler) aerobik kademede giderilebilmektedir. Bu çalışmada Türkiyede yaygın olarak kullanılan azo boyalarının anaerobik ve anaerobik/aerobik ardışık ortamlarda arıtılabilirlikleri araştırılmıştır. Çalışmanın ilk kademesinde 0-3200 mg/i arasında değişen Reaktif Siyah 5, Direkt Kırmızı 28, Direkt Siyah 38, Direkt Kahverengi 2, Direkt Sarı 12 boyaları test edilmiştir. Boyaların renklerinin 30-50 saat arasında büyük oranda giderildiği gözlenirken, boyalar yapısındaki azo bağının kırılması sonucu oluşan araomatik aminler ortamda birikmiştir. Çalışmanın sürekli beslemeli olan ikinci kısmında ilk önce 100 mg/l Reaktif Siyah 5 ve Direkt Kırmızı 28 boyası içeren sentetik atıksuyun Yukarı Akışlı Anaerobik Çamur Yatak Reaktör (YAÇYR) ve Sürekli Karıştırmalı Tank Reaktör (SKTA)'de arıtımında organik yükleme, boya yükleme, hidrolik bekletme süresi ve besin /mikroorganizma oranı gibi işletim parametrelerinin besi maddesi, renk giderimine ve metan gazı üretimine etkileri araştırılmıştır. 100 mg/l Reaktif Siyah 5 boyasını arıtan toplam sistemde 2.73 g/m3.h boya yüklemesi ve 1.52 günlük hidrolik bekletme süresinde % 75 KOİ and % 88 renk giderme verimleri elde edilmiştir. Oluşan metan gazı yüzdesi ise %66 ölçülmüştür. Daha sonra aynı sistemde 100 mg/l Direkt Kırmızı 28 içeren sentetik atıksuyun arıtımında boyanın giderimi üzerinde substratin (glikoz) ve alkalinitenin (NaHCO3) etkisi araştırılmış, düşük substrat ve alkalinite olduğu durumlarda bile rengin etkin şekilde giderildiği bulunmuştur. 0-4000 mg/l arasında değişen Direkt Kırmızı 28, Direkt Siyah 38, Direkt Kahverengi 2, Direkt Sarı 12 boyalarının arıtımında boyar maddelerin yüksek derişimlerde bile boyanın yüksek oranda (%70-100) mineralize edildiği bulunmuştur. Renk giderim verimleri gerçek yün boyama atıksuyu ile yapılan çalışmalarda %80-91 arasında değişirken, pamuklu tekstilendüstrisi atıksularmda % 40-77 arasında olmuştur. KOİ giderim verimleri ise Yün boyama endüstrisi atıksuları için % 83-96, Pamuklu tekstil atıksularmda ise % 39-82 arasında değişmiştir. YAÇYR'de metan üretimlerinde azalma gözlenmemiştir. Son olarak da geri devir oranının YAÇYR'de KOİ giderim verimi ve tüketilen alkalinite üzerine olan etkisi incelenmiş, geri devir oranının verim özelliklerini (KOI, renk ve metan gazı) arttırdığı, kullanılacak alkaliniteyi de azalttığı bulunmuştur.
Azo dyes are colorants containing one or more azo (N = N) bonds in their structure. Azo dyes are used as colorants in textile, plastic, paper, mineral oil, food and cosmetic industries. They constitute 60-70% of the paints used in industries. Azo dyes are mostly used in textile dyeing. They are seen as a problem in wastewater treatment due to their color, biologically difficult decomposition, persistence and potential toxic effects on living things. Azo dyes tend to break down with conventional aerobic processes because of their tendency to receive excess electrons and anaerobic processes are needed. The resulting intermediates (aromatic amines) can be removed in the aerobic step. In this study, azo dyes commonly used in Turkey anaerobic and anaerobic / aerobic environment in consecutive treatability were investigated. In the first stage of the study, Reactive Black 5, Direct Red 28, Direct Black 38, Direct Brown 2, Direct Yellow 12 dyes ranging between 0-3200 mg / i were tested. While it was observed that the colors of the dyes were removed to a great extent between 30-50 hours, the intermediate amines formed as a result of the breakage of azo bond in the dyes structure were deposited in the medium. In the second part of the study which is continuously fed, firstly, synthetic wastewater containing 100 mg / l Reagent Black 5 and Direct Red 28 dye is treated with organic loading, dye loading, hydraulics in Upstream Anaerobic Sludge Bed Reactor (YACYR) and Continuous Mixed Tank Reactor (SKTA). The effects of operating parameters such as residence time and nutrient / microorganism ratio on nutrient, color removal and methane gas production were investigated. In the total system that purified 100 mg / l Reactive Black 5 dye, 75% COD and 88% decolorization efficiencies were obtained with the loading of 2.73 g / m3.h and 1.52 days hydraulic holding period. The resulting methane gas percentage was 66%. Subsequently, the effect of substrate (glucose) and alkalinity (NaHCO3) on the removal of dye in the treatment of synthetic wastewater containing 100 mg / l Direct Red 28 in the same system was investigated and it was found that the color was effectively removed even in cases of low substrate and alkalinity. In the treatment of Direct Red 28, Direct Black 38, Direct Brown 2, Direct Yellow 12 dyes ranging from 0-4000 mg / l, dyes were found to be highly mineralized (70-100%), even at high concentrations. Color removal efficiencies ranged between 80-91% in studies with real wool dyeing wastewater, while it was between 40-77% in cotton textile industry wastewaters. COD removal efficiencies ranged between 83-96% for wool dyeing industry wastewaters and 39-82% for cotton textile wastewaters. No decrease in methane production was observed in YACYR. Finally, the effect of the recycle rate on COD removal efficiency and consumed alkalinity in YACYR was investigated and it was found that the recycle rate increased the yield properties (COD, color and methane gas) and decreased the alkalinity to be used.
Azo dyes are colorants containing one or more azo (N = N) bonds in their structure. Azo dyes are used as colorants in textile, plastic, paper, mineral oil, food and cosmetic industries. They constitute 60-70% of the paints used in industries. Azo dyes are mostly used in textile dyeing. They are seen as a problem in wastewater treatment due to their color, biologically difficult decomposition, persistence and potential toxic effects on living things. Azo dyes tend to break down with conventional aerobic processes because of their tendency to receive excess electrons and anaerobic processes are needed. The resulting intermediates (aromatic amines) can be removed in the aerobic step. In this study, azo dyes commonly used in Turkey anaerobic and anaerobic / aerobic environment in consecutive treatability were investigated. In the first stage of the study, Reactive Black 5, Direct Red 28, Direct Black 38, Direct Brown 2, Direct Yellow 12 dyes ranging between 0-3200 mg / i were tested. While it was observed that the colors of the dyes were removed to a great extent between 30-50 hours, the intermediate amines formed as a result of the breakage of azo bond in the dyes structure were deposited in the medium. In the second part of the study which is continuously fed, firstly, synthetic wastewater containing 100 mg / l Reagent Black 5 and Direct Red 28 dye is treated with organic loading, dye loading, hydraulics in Upstream Anaerobic Sludge Bed Reactor (YACYR) and Continuous Mixed Tank Reactor (SKTA). The effects of operating parameters such as residence time and nutrient / microorganism ratio on nutrient, color removal and methane gas production were investigated. In the total system that purified 100 mg / l Reactive Black 5 dye, 75% COD and 88% decolorization efficiencies were obtained with the loading of 2.73 g / m3.h and 1.52 days hydraulic holding period. The resulting methane gas percentage was 66%. Subsequently, the effect of substrate (glucose) and alkalinity (NaHCO3) on the removal of dye in the treatment of synthetic wastewater containing 100 mg / l Direct Red 28 in the same system was investigated and it was found that the color was effectively removed even in cases of low substrate and alkalinity. In the treatment of Direct Red 28, Direct Black 38, Direct Brown 2, Direct Yellow 12 dyes ranging from 0-4000 mg / l, dyes were found to be highly mineralized (70-100%), even at high concentrations. Color removal efficiencies ranged between 80-91% in studies with real wool dyeing wastewater, while it was between 40-77% in cotton textile industry wastewaters. COD removal efficiencies ranged between 83-96% for wool dyeing industry wastewaters and 39-82% for cotton textile wastewaters. No decrease in methane production was observed in YACYR. Finally, the effect of the recycle rate on COD removal efficiency and consumed alkalinity in YACYR was investigated and it was found that the recycle rate increased the yield properties (COD, color and methane gas) and decreased the alkalinity to be used.
Açıklama
Anahtar Kelimeler
Azo Boyaları, Anaerobik/Aerobik Ardışık Arıtım, Aromatik Amin, Renk, Mineralizasyon, Azo Dyes, Anaerobik/Aerobik Sequential Treatment, Aromatic Amine, Color, Mineralization
