Carmen Téllez

Dynamics of ciliated protozoa communities in activated sludge process

Abstract The purpose of this research is to describe and examine the importance of ciliated protozoan communities in the activated-sludge process. During this study a total number of 21 species of ciliates was recorded and 19 physico-chemical variables measured in the wastewater. The presence of the most common species of ciliates was related to plant operational parameters using multivariate statistical procedures. Principal Component Analysis with Varimax rotation performed on the total biological and non-biological set of data showed that six component factors explained 73% of the variability of the process. The first factor has a significant biological importance; it groups together the species of ciliates and explains 25% of the variability of the sewage plant. This study helps to understand the ecology of these organisms and the operational and control methods of the activated-sludge process.

Diversity of free-living ciliates in the sandy sediment of a Spanish stream in winter

This study had two objectives: to determine the number of (phenotypic) ciliate species co-existing in 1 m2 of sandy river sediment at a maximum temperature of 4 °C; and to determine the ecological mechanism(s) facilitating their co-existence. The ciliate community was diverse (65 species [8 of which are new], belonging to 50 genera, from 17 orders). The sediment supported a superficial mat of diatoms (> 30 species). These served as food for at least 16 ciliate species. The size frequency distribution of ingested diatoms was almost identical to that for the diatoms in the sediment: thus the probability of a diatom being ingested appears to be a simple function of its relative abundance. Two factors were probably important for the co-existence of ciliate species: wide variation in cell size and shape enabled them to occupy most habitats; and they deployed a variety of feeding mechanisms to consume the variety of microbial food types. Taken as a whole, the ciliate community was capable of feeding on all microbes, including other protozoa, up to a size of about 80 μ;m. Considering the broad diversity of ciliate habitats available within 1 m2, the importance of physical transport processes in the river basin, and the known cosmopolitan distribution of many ciliate species, it is believed likely that the species richness we recorded is representative of the expanse of sandy sediment in this river, on this occasion.

Effects of habitat quality on ciliated protozoa communities in sewage treatment plants

Abstract Ciliated protozoa communities and physico‐chemical variables were measured in an activated‐sludge sewage‐treatment plant in order to know the influence of the environmental conditions on the ciliate populations during biological treatment. Data of biological and not biological variables were submitted to stepwise multiple regression analysis, revealing which environmental variables are important for the development of each ciliate species and for the whole ciliate population.

The influence of detergents on the development of ciliate communities in activated sludge

The present study was conducted in a full-scale activated-sludge plant to evaluate the influence of detergent concentration on the development of ciliated protozoa during the biological treatment of wastewater. Density and diversity of ciliates were determined in relation to detergents entering the aeration tanks. Results suggest that a threshold of detergent concentration in wastewater entering the aeration tanks for an efficient biological process is 10 mg L−1. Values higher than this, yield a significant decrease in ciliate populations.

Cinetozona pyriformis n. g., n. sp.: a Relative of the Ciliate Genera Urozona and Cinetochilum (Ciliophora, Scuticociliatida)

Cinetozona pyriformis n. g., n. sp. is a very small scuticociliate recently found in a freshwater artificial pond in Madrid, Spain. This new ciliate is here described using silver impregnation techniques. C. pyriformis bears a girdle of cilia near the equator ot the cell, similar to the genus Urozona Schewiakoff, 1889, while the oral structures resemble those in the genus Cinetochilum Perty, 1852. The ciliates systematic position is discussed, and its inclusion in the family Cinetochilidae is proposed.

New aspects of the morphology and morphogenesis of Gonostomum strenuaEngelmann, 1862 (ciliophora, hypotrichida)

Summary The morphology and morphogenesis of a population of the hypotrichous ciliate Gonostomum strenua, found in moss samples from emergent stones collected in the Guadarrama River (Central Spain) is described. This population shows slight variations in morphology compared to the Chinese population studied by Song , (1990). The main differences between the European and Asian population appear in the first stages of morphogenesis. New data on infra-ciliature and cysts are also shown.