Activated Sludge Microbiology Problems and Their Control

Michael Richard,
Ph.D. Sear-Brown
Fort Collins, CO 

Many problems can develop in activated sludge operation that adversely affect effluent quality with origins in the engineering, hydraulic and microbiological components of the process.

The real "heart" of the activated sludge system is the development and maintenance of a mixed microbial culture (activated sludge) that treats wastewater and which can be managed. One definition of a wastewater treatment plant operator is a "bug farmer", one who controls the aeration basin environment to favor good microbiology.

This paper will discuss the types of microbiological problems that can occur in activated sludge operation. These include dispersed (non-settleable) growth, pin floc problems, zoogloeal bulking and foaming, polysaccharide ("slime") bulking and foaming, nitrification and denitrification problems, toxicity, and filamentous bulking and foaming.

The best approach to troubleshooting the activated sludge process is based on microscopic examination and oxygen uptake rate (OUR) testing to determine the basic cause of the problem or upset and whether it is microbiological in nature. These methods are easy, fast and inexpensive compared to other approaches, and are generally understandable and accepted.

Taxonomy

• Sludge Treatment
• Sludge Management
• Microbiology
• Water microbiology
• Sludge Treatment & Management

1 Comment

1. Bacteria are living beings like you and me who need a biological environment to grow. Mud is the last phase of natural transformation of organic matter that has not followed its natural process of elimination. All organic matter must nourish a living being. When it does not do Mother Nature triggers the process of destruction of this organic matter. When this process does not complete, the residue becomes mud.

   If a living organic matter is eliminated between 12/15 days in natural process, in sludge the time counts in month / year. Bacteria found in mud are dead. We can not reactivate them.

   Sewage sludge contains dead organic matter, putrefying, dead bacteria, dissolved chemical pollution. A medium low in oxygen. By aerating the medium, the medium is further oxidized, creating uncontrollable chain chemical reactions.

   A medium whose biological characteristics have disappeared for the most part. Despite all this, artificial intelligences try by all means to make a rotten environment an idyllic environment for the development of bacteria.

   How does man, an integral part of biology, come to the point of discrediting the biological?