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Environmental Best Practices, Part 3

(October 2008) posted on Mon Oct 06, 2008

Structuring your company around safe environmental practices is becoming a necessity


By Neil Bolding, Steven Abbott

But complications do exist. Bacteria can’t get rid of everything. They can’t cope with heavy metals, and they struggle with hydrocarbon solvents that are not water miscible. Therefore, high quantities of these substances should not be going into the sewage system. That’s why printers have strict no-go limits on certain types of chemicals.

 

Effluent volume

If you throw a lot of water down your drain, you can make your waste look rather good because it’s diluted. But the sheer volume of water you use can create a double problem. First, supplying everybody with nice, clean water is becoming increasingly difficult in many parts of the world, and bills for water are rising sharply to reflect this fact. Secondly, all that water can overwhelm the sewage-treatment facilities, which prefer a slow and steady process to keep the bacteria happy. Therefore, high dilution is not the solution.

 

Percent solids and BOD/COD

Assuming you are not attempting to mask issues with excess water, you have three criteria by which you can measure your load on the sewage system.

Percent solids The higher the percentage of solids in your effluent, the more solid waste you’re putting into the system. Some of this will eventually be eaten by bacteria in the treatment systems, and some will simply get filtered out. In both cases, the more solid waste there is, the harder the sewage system has to work and the more you’ll be charged to become or stay in compliance. Incorporating a filter system into your own plant to process waste is en effective way to reduce the waste load and your disposal costs. This can be a simple mat/pad filter or a more extensive flocculating system to remove so-lids from the liquid waste.


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