Adaptation of micro- and metafauna in activated sludge with microbial augmentation to shock loading with amaranth

Abstract

Wastewaters from the industrial sector and, in particular, those from the textile industry have a diverse composition of organic dyes. These dyes are xenobiotics for living organisms and, falling into natural water, can lead to severe consequences for aquatic flora and fauna. This is the case with the azo-dyes, such as, for example, the amaranth. The adaptive responses of the micro- and metafauna communities in activated sludge towards shock loading of high concentrations of the azo-dyes in wastewater treatment plants (WWTPs) have been poorly studied. The aim of this research was to study the adaptation mechanisms of the communities of micro- and metafauna in activated sludge towards the shock loading of amaranth (200 mg/L)with and without the addition of Pseudomonas aureofaciens AP-9 as a bioaugmentation agent (3.03 × 107 cells/mL). To achieve this, the change in the quantities of key groups of micro- and metafauna was monitored in the course of a model biodegradation process involving real activated sludge from a WWTP and toxic pollutant amaranth at a concentration of 200 mg/L. The results showed that in the case of such shock loading with amaranth, the microfauna communities changed very quickly. In addition, a positive bioaugmentation effect of the added strain of Pseudomonas aureofaciens AP-9 was observed for the micro- and metafauna. The bacteria in a homogenous form provide easily accessible food for the macro-organisms and contribute to their adaptation in the conditions of a toxic shock. This is particularly pronounced in the representatives of free-swimming ciliates and small flagellates.