NİTRİFİKASYON BAKTERİLERİNİN AKTİVİTELERİNİN NİTRİT OKSİDASYONU, NİTRAT FORMASYONU VE KARBON DİOKSİT FİKSASYONU İZLENEREK AKTİF ÇAMUR YÖNTEMİ SIRASINDA ALLYLTHIOUREA AND AZİT METABOLİK İNHİBİTÖRLERİNİN VARLIĞINDA ARAŞTIRILMASI

İki metabolik inhibitörün nitrifikasyon bakterileri üzerindeki etkileri aktif çamur yöntemiyle atık su arıtımı sırasında araştırıldı. ATU ve azitin tesirleri kesikli reaktör sisteminde nitrit oksidasyonu, nitrat formasyonu ve karbon dioksit fiksasyonu deneyleriyle ölçüldü. Deneylerde kullanılan biyokütle örnekleri sürekli, tam karışımlı, laboratuar ölçekli aktif çamur reaktöründen alındı. ATU, nitrit oksidasyonu ve nitrat formasyonu hızlarını inhibe etmedi, fakat CO2 fiksasyonu hızını %50 oranında inhibe etti. Azit, beklendiği üzere, nitrit oksidasyonu, nitrat formasyonu ve CO2 fiksasyonu hızlarını inhibe etti. CO2 fiksasyonunun azit tarafından inhibisyonu, nitrit oksitleyen bakterinin (NOB) aktivitesi de inhibe olduğunu gösterdi, çünkü bakteri enerji eksikliği nedeniyle inorganik karbonu bünyesine alma yeteneğini yitirdi. Ayrıca, nitrit oksidasyonu, nitrat formasyonu ve CO2 fiksasyonu arasında bir bağlantı olduğu da bu çalışmayla gösterilmiş oldu. Karışık bakterilerin bulunduğu ortamlarda, AOB ve NOB aktivitelerinin ayırt edilebilmesinin mümkün olduğu da kanıtlamış oldu.

Anahtar Kelimeler:

Nitrit oksidasyonu, nitrat formasyonu, CO2 fiksasyonu, aktif çamur, atık su arıtımı, allylthiourea (ATU), azit, amonyak oksitleyen bakteri (AOB), nitrit oksitleyen bakteri (NOB)

INVESTIGATION OF NITRIFYING BACTERIAL ACTIVITIES BY MONITORING NITRITE OXIDATION, NITRATE FORMATION AND CARBON DIOXIDE FIXATION DURING ACTIVATED SLUDGE TREATMENT IN THE PRESENCE OF METABOLIC INHIBITORS ALLYLTHIOUREA AND AZIDE

The effects of two metabolic inhibitors on nitrifying biomass during activated sludge wastewater treatment were investigated. The impact of allylthiourea [ATU (C4H8N2S)] and azide (N3) was measured by nitrite oxidation, nitrate removal and carbon dioxide fixation (CO2) assays in batch experiments performed using mixed liquor obtained from a complete-mix, bench-scale, activated sludge system. ATU did not inhibit nitrite removal or nitrate formation rates, but did inhibit CO2 fixation rates by approximately 50%. Azide did inhibit nitrite removal, nitrate formation and CO2 fixation rates, as expected. Inhibition of CO2 fixation by azide also indicated that the activity of nitriteoxidizing bacteria (NOB) was inhibited since the bacteria were not able to fix inorganic carbon. Additionally, it was demonstrated that there was a connection between nitrite removal, nitrate formation and CO2 fixation. Also, it was showed that it is possible to distinguish the activities of AOB and NOB in mixed cultures using these two inhibitors.

Keywords:

Nitrite oxidation, nitrate formation, carbon dioxide fixation, activated sludge, wastewater treatment, allylthiourea (ATU), azide, ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB),

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