Elżbieta Bezak-Mazur, Renata Stoińska, Bartosz Szeląg
Politechnika Świętokrzyska

Sludge sedimentation depends on various factors like: air temperature, quality of wastewater (BOD), characteristics of a bioreactor (sludge age, oxygen concentration in nitrification chamber, recirculation rate, concentration of sludge in a bioreactor), dosage of coagulants for phosphorus removal and a presence of filamentous bacteria. However, still there is a lack of a mathematical model that would established the dependency between all these inputs, because of their number, and sludge sedimentation. In the presented study, such model is proposed, moreover its structure allows for a direct interpretation of its parameters, making it especially useful for operators of treatment plants. The article presents the application of the logistic regression for the estimation of sludge sedimentation potential, using the characteristic of the sludge (concentration and temperature) in a respect of the presence of filamentous bacteria. The sludge deterioration was measured using a threshold a value of the Sludge Volume Index (SVI = 150 mg/dm3). Results suggests that Sphaerotilus natans and Nostocoida sp. bacteria are the most noticeable factor for the sludge deterioration and the sediment potential.

Słowa kluczowe
bakterie nitkowate, objętościowy indeks osadu, regresja logistyczna

Evaluation of the Impact of Operational Parameters and Particular Filamentous Bacteria on Activated Sludge Volume Index – a Case Study

Key words 
filamentous bacteria, sludge volume index, logistic regression

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