WHEN ENGINEERS AND BIOLOGISTS COLLIDE!

It is common to see that in such a highly integrated field of biotechnology and industrial microbiology where there is suppose to be a fusion or input of knowledge between microbiologists and bioprocess engineers we have a situation where both parties do not really see 'eye to eye'. This has more than often resulted in process failure or the bioprocess do not really run as the targeted expections.

PENICILLIN FERMENTATION
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In the history of penicillin fermentation or any other antibiotics, the progress in design of fermentors have been slow or static. In fact there is not much change in the design of CSTRs until now. Nor has the engineering designs improvements yield drastic improvements in the penicillin yield! The increase in the yield or productivity of penicillin fermentation has been more to the improvement of the strain by geneticists, biochemists and microbiologists!!

WASTEWATER TREATMENT IN BIOREACTORS
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A very good example is seen in the design of bioreactors such as bioreactors used in biological wastewater treatments. Bioreactors in biological wastewater treatments are often considered the biggest man made bioreactor using mixed cultures and operating continuously under septic conditions.

It is really hard to see wastewater treatment plants working efficiently and most bioreactors ending up by not performing to the expectations

There are valuable lessons to be learnt from this situation. For decades it seems that the engineers have a field day designing, building and operating the various biological treatment plants. The engineers only see the process as a " simple engineering" process, whereby there is input of substrate into the bioreactor, and where the microorganisms are present easily working themselves out happily eating away the pollutants thus treating the wastewaters. They only describe the process by a few key parameters which they think and understand to operate and control the bioreactors. Usually the standard parameters are BOD, COD, SS among others,

They do not see there is the need to understand the various biological and biochemical processes occurring in the biological reactor. As far as they are concerned, they designed the bioreactors more as the structure and volume to hold a certain effective volume of wastewaters over a certain designed hydraulic retention time.

Sad to say in such designs they only use the so called standard calculations from standard engineering texts in civil engineering. They do not take into considerations the:
1 Type of microbes and biochemical reactions that will be taking place as function of time or space
2 The supply and utilization of oxygen by the microorganisms in the bioreactor
3 Adaptation and wash out rates of microorganisms
4 Effect of toxicity and cumulative effects of toxic conditions
5 Nutritional and physiological needs of the various microorganisms
6 Behaviour of the populations of microorganisms in the bioreactor

The way they act as if nothing bad will ever happened or that all the bad processes will be taken care by GOD or blame it on poor understanding and managing of the treatment plants by the plant technicians.

In a way, we cannot blame this situation from happening as what is important is that the factory or the plant must have a biological treatment plant to get a certificate of fitness or license to operate. Whether it work or not is secondary and not the problem to the engineers that build the treatment plant

Why do most treatment plants fail after some period of operation? In the first place we see the whole scenario of the plant failure as a chain reaction of errors starting from poor engineering design and operation which will ultimately affect the performance of the microorganisms leading to poor treatment of the wastewaters. It should be noted that with just any process the range of optimal operating conditions in wastewaters operate within a very narrow babd of operating conditions. Change in any operating parameter will either lead to changes in the activity of the microorganisms , or worst still the change will affect the change of many other parameters either simulataneously or linearlr in a series of related events.

Changes to the process can either be immediate such as ' poisonings' which will kill the microorganisms or the failure of blowers leading to immediate anaerobic conditions that will result in abrupt plant failure. The second change occur slowly and cumulatively over a long period which will lead to gradual process failure

It is strange that if we surf the internnet and look at the various suppliers and contractors that sell or build the various biological treatment all GUARANTEE that their biological treatment plants will work wonderfully! Just you wait and you will see if such claims are true. As Tsun Zu the millitary strategist said once " In war, you win by deception". Business is war! They will promise you everything until you installed the tretment plant.

It is amazing in a few sites of suppliers and contractors of aerobic biological wastewater treatment plants they will tell certain parameters such as BODm COD and SS but failed to indicate the Dissolved oxygen readings of their treatment plants!!!!! Mind you we are talking about processes that uses oxygen.

They dont bother coming clean. All they bother telling you is their magnificient track record of having built this and that at here and there. Rarely will they give you the data of the actual plant or lab performance feaibility studies! What you will get are promises and 'guarantees' that it will work!

I cannot see why they dont give the other additional data parameters as the wastewaters go through the various unit processes so that the customer can assess the data themselves or employ an INDEPENDENT CONSULTANT to vet the technical data? This would have ensured the buyer that they are not cheated and will be getting good value for their money and freedom from future headaches?

Maybe the engineers 'hate' the microbiologists for their ability to see the process. Or is it because they think they are righter than God? or they are always correct?
If this is so why do most....MOST..... MOST treatment plants failed?

The point is while it is true engineers are trained to design and build these bioreactors, they must really try to understand the processes that is occurring in the bioreactor to come up with better design. It is time they stop the bad habit of designing treatment plants based on the number of PE for loadings pf the treatment plant or reduction of BOD and COD based on some standard references

Major designs like this must involve feasibility and technical studies to ensure that the treatment plant really will work and their range of test loads