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Wastewater treatment process and plant

Wastewater treatment is a tricky business.   Wrapped up in the water molecules, like a creeper around a tree, soluble organic material becomes inextricably meshed in the liquid medium.

wastewater treatment

Engineers apply various technologies to  tease the creeper away from the tree.  The tried and tested method is to change the phase of the contaminant.  Wastewater does not hold on to gases and solids.  However if the contaminant is solubilized in water, phase change is not so easy.

Wastewater treatment

Freezing is a good trick and so too boiling.  Both processes guarantee results - at great cost.  Another option is to use force.  Rip away filtration or more gentle electro-coagulation.  Neither option is without cost and process draw-backs.  Waste waters organically polluted, would be water contaminated with food processing residual or at the other end, sewage.  In treatment of these waste waters, engineers have a fifth option - biological methods.

If microbes, flora or fauna, could be offered the locked up food in the waste water, perhaps and unwittingly, in their digestion process, they might clean up the waste water as part of the deal.  All the design engineer has to do is ensure that the perfect conditions are maintained for optimum biological activity.  Age old tools include balanced pH, adequate nutrient availability, amenable temperature, enough retention, enough aeration and very importantly no disruptive chemicals in the soup.

Having created a most affable environment, the final step required is to separate the microbes, flora and fauna from the water.   Flora and fauna separate from water easily.  Not so microbes and in particular bacteria.  At a specific gravity of 1.04, bacteria only just sink in static water.  Their settling velocity is about 1m per hour.  That is it takes bacteria 60 minutes to settle one meter.

This is a bottleneck in the wastewater treatment process and design engineers spend alot of time concocting better methods to separate bacteria from the parental liquid environment.  At the moment MBR (membrane bioreactor) is touted as a viable method to speed up the bacteria/liquid separation process.  Although highly effective, this method does employ the rip away filtration methods with associated capital and running costs.

At HWT, we have developed a biological treatment method whereby microbes, flora and fauna coexist in a wet, but not saturated environment.  Of the many advantages offered by SOG trickling filtration, one of its principle benefits is the omission of the liquid/solid separation bottleneck experienced in conventional waste water treatment plants.