It is often in the seemingly simple tasks that an endeavor's true difficulty is revealed. No one knows this better than Daniel Noguera. The University of Wisconsin-Madison researcher is trying to accomplish what 30 years of research efforts have failed to do -- isolate in pure culture the microorganisms responsible for enhanced biological phosphorous removal (EBPR). Undeterred, Noguera is nearing success in isolating these elusive bugs. All he needed to do was shed a little light on the matter.

For all intents and purposes the process of EBPR is a black box for microbiologists. Despite three decades of engineering and refinement to this common treatment process, researchers know relatively little about the various polyphosphate accumulating organisms (PAO) responsible for removal of phosphorous from the waste stream. In fact, it has only been in the last six years that Candidatus Accumulibacter phosphatis was identified as the primary PAO responsible for EBPR. Unfortunately, another discovery is that Cand. A. phosphatis doesn't like living alone. Attempts at growing this and other PAOs in isolation have only met with failure.

Noguera and his team believe that isolation of Cand. A. phosphatis is the first step in improving the performance and reliability of enhanced biological phosphorous removal. Though many treatment facilities experience few difficulties in maintaining effluent limits through EBPR, a handful still struggle to avoid intermittent phosphorous spikes. When EBPR breaks down, chemical treatment can be employed. But chemical treatment is not without its drawback. Chemical intervention increases costs and generates undesired solid waste through precipitation.

Isolation of PAOs, such as Cand. A. phosphatis, could also yield valuable information concerning how fast these microbes grow and how quickly each consumes specific contaminants. Faster bugs mean smaller reactors, and therefore, lower capital costs. Slower bugs result in larger reactors, and therefore, higher costs in the construction of the treatment plant.

But more than just cost savings, a full understanding of the role Cand. A. phosphatis and other PAOs play in the process, will lay the groundwork for developing biological solutions that allow treatment facilities to adjust to and perhaps even foresee breakdowns in phosphorous removal.

"You can think about EBPR as a process that is well understood from an engineering perspective. But our understanding of it is limited to a narrow set of conditions that have been proven to work," explains Noguera. "With a pure culture, you could test in the lab other conditions and see how the organism responds to changes in environmental conditions, such as pH or dissolved oxygen, and understand what makes the bug happy accumulating phosphorus. We can do a lot of that now, using mixed cultures, but with mixed cultures the results are difficult to interpret."

To date, attempts at isolation PAOs have relied on trying to duplicate the environment within an EBPR treatment plant. However, rather than attempting to reproduce the activated sludge environment, Noguera and his team intend to reproduce what PAOs might be doing when they are not in activated sludge. For example, genetic study of various PAOs has shown photosynthetic activity outside of the treatment plant, so phototrophic enrichments will be one of the main culturing conditions.

With the resources provided by the Paul L. Busch Award, Noguera and his team will aggressively seek the isolation of PAO from EBPR reactors. By not following traditional approaches to retrieve PAO from EBPR systems, Noguera expects to obtain isolates that may not be dominant PAOs in current EBPR configurations, but offer alternatives for the creative development of novel, cost-effective, and reliable EBPR processes.

Though PAO isolation may be a long shot, if Noguera's innovative enrichment approaches are successful he will have made an invaluable first step in understanding why some facilities cannot achieve reliable EBPR and perhaps lay the groundwork for finding a solution. Moreover, Noguera's research will allow us to explore the limits of EBPR well beyond the operating conditions currently accepted in practice.