Protozoa and metazoa relations to technological conditions of non-woven textile filters for wastewater treatment

Abstract

The objective of this study was a preliminary identification of basic groups of micro-organisms in the cross-sectional profile of geotextile filters for septic tank effluent (STE) treatment and their relations to technological conditions. Reactors with textile filters treating wastewater were investigated on a semi-technical scale. Filters were vertically situated and STE was filtered through them under hydrostatic pressure at a wastewater surface height of 7-20 cm. Filters were made of four layers of non-woven TS 20 geotextile of 0.9 mm thickness. Various groups of organisms were observed; the most abundant group comprised free-swimming and crawling ciliates, less abundant were stalked ciliates and the least numerous were nematodes. The individual counts of all groups of micro-organisms investigated during the study were variable according to time and space. The high abundance of Opercularia, a commonly observed genus of stalked ciliates, was related to the high efficiency of wastewater treatment and dissolved oxygen concentration of about 1.0 g/m3. Numbers of free-swimming and crawling ciliates had a tendency to decrease in relation to the depth of filter cross-sectional profile. The variability in counts of particular groups of organisms could be related to the local stress conditions. No correlation between identified organism count and total mass concentration in the cross-sectional filter profile was found.

Comparison of the Results from Microscopic Tests Concerning the Quality of Activated Sludge and Effluent

“…There are three basic protozoan groups in activated sludge: ciliates, flagellates, and amoebae. Protozoa are heterotrophs and feed mainly on bacteria and other small microorganisms [17]. It is commonly believed that the primary function of these organisms is to improve the quality of outflow by eliminating bacteria that are dispersed in a liquid phase or on the edges of flocs [18].…”

Efficiency of Nutrient Removal from Household Wastewater in Nonwoven Bioreactors

“…Due to the variety of properties and conditions (nonwoven thickness and type, supply regime, type of wastewater) there is a very wide range of potential research directions for nonwoven filters technology. Similar to what is described in this paper, types of filters have already been investigated; however, those studies were carried out under other conditions for other thicknesses and other constructions [10][11][12][13]. Nonwoven filters can potentially be useful in practice as a device for septic tank effluent treatment, and significantly reduce the risk of clogging.…”

Remoção de Giardia e Cryptosporidium, ocorrência de microsporídios e caracterização da microfauna de um sistema combinado de tratamento de esgoto

“…correlação positiva moderada entre O. coarctata e sólidos suspensos fixos pode estar relacionada quanto ao seu hábito bacterívoro, pois de acordo com Drzewicki e Kulikowksa(2011), espécies do gênero Opercularia estão presentes em ambientes ricos em bactérias dispersas, cuja condição coincide com a alta carga orgânica. Os sólidos suspensos fixos possuem tamanho similar aos das bactérias (menor que 2 µm) (BOENIGK e NOVARINO, 2004) podendo então serem considerados como potenciais alimentos de O. coarctata.Nos pontos 2, 3 e 4, as correlações positivas moderadas e fortes de O. coarctata com OD podem estar relacionadas aos valores de concentrações acima de 1 mg/L, pois segundoSpychała et al (2015) é verificado maior número desse organismo em efluentes cujas concentrações de OD são acima de 1 mg/L. Além disso, esses mesmos autores constataram que a presença de O. coarctata foi coincidente com a alta eficiência de tratamento do esgoto.…”