Bulking of activated sludge in the biological treatment of municipal and industrial wastewater, due to the massive development of filamentous bacteria Type 021N

Abstract

A research of the causes and consequences of bulking of activated sludge was conducted at existing biological wastewater treatment plants (municipal and local at an industrial enterprise). The filamentous bacterium that was caused the bulking of the activated sludge in the studied treatment plants was identified as Type 021N. It was established that the studied filamentous bulking causes a significant deterioration of the technological characteristics of activated sludge flocs and it is accompanied by suppression of the nitrification process. To suppress the bulking of activated sludge two methods of suppressing the inflow of hydrogen sulfide into biological treatment plants were successfully used: blowing from wastewater at municipal treatment plants and inhibiting its formation at local treatment plants in the settling and laminar flow zones.

Quantitative Determination of the Strength of Activated Sludge Flocks in Biological Treatment Technologies

“…Такий мул часто зустрічається при запуску аеротенку та при інтенсивному надходженні мулу, коли велика кількість надлишкового мулу видаляється, а його час перебування в системі "аеротенк-вторинний відстійник" скорочується. З дозріванням мулу пластівці стають більш компактними, збільшуються в розмірі, утворюється біополімерний гель, який захищає клітини в пластівцях від токсикантів і утримує клітини мікроорганізмів [7][8][9]. Такі пластівці легко відокремлюються від очищеної води у вторинних відстійниках.…”

Ecophysiology of novel microorganisms in wastewater treatment systems revealed by metatranscriptomics: Illuminating bacterial communities of activated sludge

“…Even though the activated sludge process was described in the beginning of 20 th century (Ardern and Lockett, 1914), due to its complex composition (Dueholm et al, 2022;Ibarbalz et al, 2013;Nielsen et al, 2004;Nierychlo et al, 2020a;Xie et al, 2021), to this day there are still many unanswered questions. There are still accruing problems such as bad settling and bulking that can result in poor performance of WWTP (Chen et al, 2023;Iurchenko et al, 2023). Various approaches exist to prevent these problems from happening, but the good WWTP with an activated sludge process depends primarily on a good microbial composition and bacterial activity.…”

“…Filamentous bacteria were always of interest in WWTPs, due to their morphology and involvement in poor settling problems that sometimes evolved into bulking episodes (Iurchenko et al, 2023;Nielsen et al, 2009). Members from Chloroflexota phylum are the most abundant and commonly related to these issues as they serve as a backbone for activated sludge flocs, with some species providing a general loose floc structure, resulting in poor settling problems (Petriglieri et al, 2018).…”