Diversity and function of the microbial community under strong selective pressure of rotifers.

We unearthed some interesting microecological discoveries while selecting for the most beneficial bacterial strains to be used as probiotics in Lecane inermis rotifer mass culture. For 3 years, we maintained the cultures of L. inermis, with selection for the highest growth rate and resistance to potential contamination.

Evaluation of the accuracy of two simple methods for microscopic activated sludge analysis.

Biological microscopic analysis is a popular method employed in wastewater treatment plants worldwide for evaluating activated sludge condition. However, many operators still have reservations regarding its reliability. In this study, we evaluated and compared two methods of microscopic sludge investigation: the sludge index (SI) and the Eikelboom-van Buijsen method (EB).

Foam-forming bacteria in activated sludge effectively reduced by rotifers in laboratory- and real-scale wastewater treatment plant experiments.

Lecane inermis rotifers were shown to diminish sludge bulking due to their ability to ingest the filamentous bacteria in activated sludge. To determine if rotifers are also able to control branched actinomycetes, we investigated three other Lecane species (Monogononta). In a week-long experiment, only Lecane tenuiseta significantly reduced the density of Microthrix parvicella and Type 0092 filaments, but in a 2-week experiment, actinomycetes were significantly reduced by most of the tested monogonont rotifers: L.

The effect of three different predatory ciliate species on activated sludge microfauna.

Bacterivorous ciliates play important roles in the functioning of activated sludge by reducing dispersed bacteria and enhancing flocculation. There are, however, no data on the resistance of this functional group of microorganisms to predation. Our experiment was conducted with activated sludge subsamples subjected to artificially introduced three predatory ciliates species.

Effect of high levels of the rotifer Lecane inermis on the ciliate community in laboratory-scale sequencing batch bioreactors (SBRs).

Due to its ability to feed on filamentous bacteria, the rotifer Lecane inermis has already been recognized as a potential control agent of activated sludge bulking, which is usually caused by the excessive growth of filamentous microorganisms. However, their effectiveness depends, in part, on their abundance. We studied the influence of high densities of L.

Experimental attempt at using Lecane inermis rotifers to control filamentous bacteria Eikelboom Type 0092 in activated sludge.

In laboratory experiments, the authors tested the efficacy of Lecane inermis rotifers in reducing the abundance of filamentous bacteria in activated sludge samples dominated by one filamentous bacterium, Eikelboom Type 0092. The experiment was conducted in three replicates and repeated three times at 1-month intervals. In all repetitions, rotifers were able to significantly reduce the density of bacterial filaments through predation.

Effect of the rotifer Lecane inermis, a potential sludge bulking control agent, on process parameters in a laboratory-scale SBR system.

The influence of a high density of rotifers, which is known to be able to control filamentous bacteria, on the parameters of an activated sludge process was examined in four professional laboratory batch reactors. These reactors allow the imitation of the work of a wastewater treatment plant with enhanced nutrient removal. The parameters, including oxygen concentration, pH and temperature, were constantly controlled.

The toxicity of selected trace metals to Lecane inermis rotifers isolated from activated sludge.

The aim of the study was to assess the toxicity of a range of trace metals to the rotifer Lecane inermis, a species tested as a potential biological tool to control activated sludge bulking caused by overgrowth of filamentous bacteria in wastewater treatment plants. LC50 values (concentration lethal to 50 % of individuals, mg dm(-3)) were ranked in the following order: Cu < Al < Fe < Zn < Sn < Mn. L.

The use of rotifers for limiting filamentous bacteria Type 021N, a bacteria causing activated sludge bulking.

The excessive growth of filamentous bacteria and the resultant bulking of activated sludge constitute a serious problem in numerous wastewater treatment plants. Lecane inermis rotifers were previously shown to be capable of reducing the abundance of Microthrix parvicella and Nostocoida limicola in activated sludge. In the present study, the effectiveness of four Lecane clones in reducing the abundance of Type 021N filamentous bacteria was investigated.