Bulking and Foaming in France: The 1999–2001 Survey

Abstract

Surveya Wastewater Treatment, To assess bulking in French wastewater treatment plants we developed a three-topic Water Quality and Hydrology approach, including analysis of i) technical assistance annual reports, ii) a questionnaire, Research Unit, Cemagref, and iii) microscopic sample observations. A seasonal effect was very apparent on the Parc de Tourvoie BP 44, F-92163 Antony cedex, France average SVI (mL/g). Three situations appear to promote bulking according to statistical analysis and operators' comments: i) low-organic loading or rapid variation in organic loading, ii) raw sewage dilution or hydraulic loading variation, iii) rapid high-organic loading. Phosphorus removal by metallic salt addition leads to an average SVI reduction of 40 mL/g. Two situations in the sludge treatment process, which call for improvement, are: Ϫ The maintaining a high MLSS concentration in the aeration tank due to the limitation of sludge evacuation, Ϫ When storing sludge for several days or weeks in sludge thickening tank, thereby favoring the formation of septic compounds, which are subsequently reintroduced in the influent. Our study highlights Type 0092 as the most frequent filamentous microorganism observed followed by Microthrix parvicella. Thiothrix spp. ranks third. Blähschlamm und Schwimmschlamm in Frankreich: Umfrage in 1999؊2001Zur Einschätzung von Blähschlammereignissen in französischen Kläranlagen entwickeln wir einen Ansatz mit drei Schwerpunkten: Analyse der Jahresberichte der Betriebe, Fragebogenaktion und mikroskopische Untersuchung von Schlammproben. Es zeigte sich deutlich ein jahreszeitlicher Effekt beim durchschnittlichen Schlammindex SVI (mL/g). Drei Situationen scheinen Blähschlamm förderlich zu sein, wie sowohl die statistische Analyse als auch die Betriebsdaten zeigen: Unterbelastung oder schwankende organische Belastung, Verdünnung des Rohabwassers oder schwankende hydraulische Belastung, rasch eintretende organische Überbelastung. Phosphorentfernung durch Zugabe von Metallsalzen führt zu einer durchschnittlichen Reduzierung des SVI auf 40 mL/g. Verbesserungswürdig ist die Schlammbehandlung: Schwierigkeiten bei der Schlammentsorgung führen dazu, dass mit hohem Schlammgehalt im Belebungsbecken gefahren wird oder Schlamm über Tage oder Wochen gelagert werden muss, was Faulprozesse fördert. Unsere Untersuchung bestätigt, dass Typ 0092 an erster Stelle der Blähschlammverursacher steht, vor Microthrix parvicella. Thiothrix spp. belegt Rang 3.

The effect of seasonal variations on floc morphology in the activated sludge process

“…However, they found that a Microthirx bacterium, which is one of the most common filamentous bacteria, was most abundant in winter, although they did not observe a clear, seasonal variation in the filaments [24]. Graveleau et al [13] found no significant seasonal differences in terms of micro-organism population distribution, although they found a seasonal pattern in SVI values. However, Flowers et al [25] found that temperature was the environmental variable that best correlated with changes in bacteria species and that bacteria species cycled through a predictable, seasonal pattern yearly, which confirms the results of the present study.…”

“…In addition, previous studies [13,24,25] have sought to identify seasonal patterns in micro-organism populations.…”

“…Some studies have found seasonal variations in ASP, especially in sludge settleability, which is measured mainly as sludge volume index (SVI). For example, Graveleau et al [13], Krult et al [14] and Oerther et al [10] found that average SVI values were higher in winter than in summer. In contrast, Wilén et al [15] and Liwarska-Bizukojc [16] found no seasonal variations in settleability properties when measured as stirred SVI and SVI at municipal wastewater treatment plants (WWTPs).…”

Parámetros fisicoquímicos asociados a la proliferación de bacterias filamentosas (Bulking filamentoso) en las plantas de tratamiento de aguas residuales mediante lodos activados: revisión sistemática

“…8,16, 19 En las PTAR el IVL es el indicador determinante de la presencia de bulking con un valor límite de 150 mL/g, no obstante el diseño de las PTAR en países como Francia, por ejemplo, permite valores hasta de 200 mL/g, siendo este el valor considerado en ese país, como el umbral más allá del cual un tanque de sedimentación no puede garantizar la adecuada separación de lodos. 18 La baja concentración de OD fue uno de los parámetros con mayor influencia en la proliferación de bacterias filamentosas, lo cual puede explicarse debido a que este grupo de microorganismos posee mayor superficie/volumen que las bacterias formadoras de floc, proporcionándoles una ventaja en la obtención de oxígeno disponible. Un lodo activado en condiciones normales generalmente tiene un OD igual o mayor a 2 mg/L, niveles que permiten controlar la proliferación de estas bacterias.…”

Microthrix parvicella abundance associates with activated sludge settling velocity and rheology – Quantifying and modelling filamentous bulking

“…Furthermore, it was measured that, in typical Danish wastewaters, the diluted SVI (DSVI) value of 120 ml/g and above suggests a poorly settling sludge (Mielczarek et al, 2012). Moreover, Graveleau et al (2003) observed bulking at an SVI value of 180 ml/g and above. Some studies assess the total extended filament length (e.g.…”