Ciliate Communities Respond via Their Traits to a Wastewater Treatment Plant With a Combined UASB–Activated Sludge System

Abstract

Assessing functional diversity of communities is an efficient method to link community composition to ecosystem quality. Still, studies using functional traits of microeukaryote ciliate communities in biological wastewater treatment plants are lacking. The present work explores the functional diversity of the ciliate protist community in a wastewater treatment plant (WWTP) operating with a combined UASB-activated sludge system, and specifically to: 1) investigate the taxonomic and functional composition of the ciliate communities over time; 2) compare taxonomic and functional diversity indices with regard to its applicability in WWPS; 3) assess the relationship between the ciliate community’s functional composition and the WWTPs temporal conditions; and 4) investigate the potential use of functional diversity as an indicator of WWTP efficiency. Totally, we recorded 21 ciliate species throughout 37 samplings. The number of species was low compared to other plants. Bacterivorous and flake-forming species were the main functional strategies found in the samples. The correlation between taxonomic and functional richness was significant, indicating a functionally redundant community. There was a correlation between the Simpson and Rao’s quadratic entropy indexes suggesting that loss of taxonomic diversity leads to a loss of functional diversity. The homogeneity of the measured physical and chemical data led to functional homogenization and redundancy (homogenous CWM) of the ciliate community. The functional diversity is positively correlated with parameters of removal efficiency, indicating a promising application in WWTPs. Future studies will broaden knowledge on functional diversity in biological wastewater treatment systems, this being a first step with the unprecedented application of this methodology in artificial ecosystems.

Functional Structure of Intertidal Ciliate Assemblages Along Salinity Gradient in Two Contrasting Estuaries Testing Paradigms in Estuarine Ecology

“…There have been a few attempts to apply BTA and functional-based approaches to ciliate communities (Moreira et al 2022;Vlaičević et al 2022). In particular, Xu et al (2018b, c) investigated the spatial and temporal variation in the functional structure and diversity of benthic ciliates in the Yangtze Estuary.…”

Morphology and Morphogenetic description of a new soil ciliate species of Notohymena indica n.sp. from Rithala waste-water treatment plant (WWTP), Delhi, India

“…In a testament for their wilderness in distribution, a large number of species of ciliates have been discovered from the wastewater-treatment plants (WWTP) world-wide (Roberts et al, 2004;Madoni, 2011;Moreira et al, 2022). Their presence has been recorded from the treated final effluent as well as even in the sewage sludge, which is a semi-solid waste by-product containing a rich mix of organic and inorganic nutrients from human waste, food waste and inorganic solids, providing a conducive idyllically nutrient-rich environment sustaining the supplies required for the growth of these unicellular organisms.…”

“…Their presence has been recorded from the treated final effluent as well as even in the sewage sludge, which is a semi-solid waste by-product containing a rich mix of organic and inorganic nutrients from human waste, food waste and inorganic solids, providing a conducive idyllically nutrient-rich environment sustaining the supplies required for the growth of these unicellular organisms. While in the effluent, they feed on bacteria and purify the final effluent (Moreira et al, 2022).…”