Biological deposition on paper machines

A paper maehine re-eireulates hundred to thousands of cubic meters of water at a pH from 4 to 8 and a temperature from 30 to 60°C. It eontains huge amount of nutrient such as starch and can be contaminated by air, water (3 to 60m /ton of paper) or furnish (recycled paper) and additives. In many ways, it can be considered as an incubator with 10 to 10 bacteria/ml. See Fig. 4-5. 

1 How do micro-organisms grow on machines of development in paper process  

Biological contamination will have two different aspects 

Planktonic bacteria are measured with plate counts e.g. of a head box sample. 

Sessile bacteria are measured either by analysing deposits taken from the machine, or by using a fouling monitor, or following the rate and nature of deposition on a reference surface in the machine using either a microscope to see individual sessile cells of enumerating some of the microbes present by plating the actual deposit. 

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