Blähschlamm / bulking sludge © BIOMONTAN GmbH

CHALLENGE HIGH SVI / BULKING SLUDGE / FLOATING SLUDGE / FILAMENTOUS BACTERIA IN WASTEWATER TREATMENT PLANTS

We solve problems with high sludge index and bulking sludge

Bulking sludge is characterized by a SVI of the activated sludge from over 150 mL/g.

Associated sludge discharge, foaming in the digestion tower and reduced dewaterability result in higher operating costs.

Filamentous bacteria almost always cause increased ISV. Therefore, microscopic system analysis and water chemistry analyses are at the beginning of every efficient treatment plan.

Causes of high sludge index and bulking sludge

High sludge index is in most cases caused by the following filamentous bacteria:

More rarely, a mass occurrence of tree bacteria (Zoogloea sp.) or extremely high fat content may be responsible.

STANDARDS

BIOMONTAN_Analytisches Labor - Mikrobiologie-Expertin am Mikroskop © Biomontan GmbH

We offer expert analysis of activated sludge, including the determination of filamentous bacteria.

All necessary analyses are carried out in our in-house laboratory by our experts.

In combination with the operating parameters determined, a specific package of measures is put together to reduce the development of filamentous bacteria.

Blähschlamm / bulking sludge © BIOMONTAN GmbH
Mikroskopie des Fadenbakteriums Typ 021N / Microscopy of filamentous bacteria Type 021N © BIOMONTAN GmbH

EXPERTISE: CHARAKTERISTIcs of the most common filamentous bacteria

Microthrix parvicella is promoted by a low sludge load, low oxygen content and water temperatures < 12° C.

This is why this filamentous organism usually leads to problems with bulking sludge and/or floating sludge in fall and spring. 

Microthrix parvicella can also cause sludge foaming if it is very filamentous.

Mikroskopie des Fadenbakteriums Microthrix parvicella / Microscopy of filamentous bacteria Microthrix parvicella © BIOMONTAN GmbH

Type 021N often occurs in systems with heavy loads or frequent shock loads from wastewater from the food industry or the introduction of sulphur compounds.

These filamentous bacteria can cause an extremely high sludge index (over 2000 mL/g).

Heavy pollution (especially by easily degradable substances), lack of oxygen, putrid conditions in the plant or in the sewer are considered to be conducive to type 021N.

Mikroskopie des Fadenbakteriums Typ 021N / Microscopy of filamentous bacteria Type 021N © BIOMONTAN GmbH

Nostocoida limicola can also cause problems in municipal wastewater treatment plants if there is a strong industrial influence from many or large indirect dischargers. 

Nostocoida limicola is a typical industrial bacterium that occurs when the C:N:P ratio is unbalanced and there is a lack of micronutrients and trace elements. The level of contamination is irrelevant.

With a high dry matter content, Nostocoida limicola can also form floating sludge.

Mikroskopie des Fadenbakteriums Nostocoida limicola / Microscopy of filamentous bacteria Nostocoida limicola © BIOMONTAN GmbH

Filamentous bacteria from the Nocardioform actinomycetes group are common causes of bulking and/or floating sludge. Gas bubbles are permanently stabilized by their branched filaments and float to the surface without dissolving.

A reliable differentiation from Microthrix parvicella is only possible by microscopic examination.

Mikroskopie des Fadenbakteriums Nocardioforme Actinomyceten / Microscopy of filamentous bacteria Nocardioform actinomycetes © BIOMONTAN GmbH
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