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Preventing duckweed, chlydophera and other algae
The reason for the proliferation of algae is largely due to the presence of above average concentrations of Nitrates and Phosphates. Algal spores bloom forming a floating blanket that prevents the uptake of oxygen by the reduced water surface area. To clean up a body of algae-infested water a healthy population of avaricious bacteria is needed to metabolize these radicals back into the natural food chain.
Small lake covered in algae
A classic example was
noted recently in the maturation river of a small town Wastewater
Treatment Works. The constant flow of nutrient rich water, exacerbated
by a sludge spill from the reactor, set up conditions favourable to
duckweed, which rapidly covered 95% of the river's surface. This meant
that the wastewater could no longer 'mature' as the river had turned
anaerobic to the extent that the final 'polishing' of impurities from
the flow could no longer take place.
BIO-SYSTEMS was called upon
to assist. This we did by first remedying the depleted activity in the
reactor. We then inoculated the river which was 70m long by 30m wide
and separated into 23 x 3m wide channels (see below). The final quality
was outside the standard and unfit for discharge (COD 146ppm and both
Nitrate and Phosphate values in excess of what is permitted). 1kg of
BIO-SYSTEMS B504 was rehydrated in two 20lt buckets of water drawn from
the river and slowly fed into the inflow at the rate of one bucket over
10 minutes.
This ensured a reasonably even distribution, carried by the inflow
current in and under the duckweed in the first two channels. We then
bowled a further 2kg of B504 into the first and second thirds of the
river, the soluble pouches permitting inoculation without getting
horribly wet.
After a few weeks, we revisited the site and the
improvement was most gratifying. More importantly, the final discharge
was back to its previous excellent quality – almost the crystal sparkle
associated with a fresh mountain stream.
Since our treatment, a minor infestation of duckweed is
recurring. This is due to the fact that the effluent is carrying excess
Phosphates (from laundry powders), a phenomenon that is shared by most
Wastewater Treatment Works. It makes sense, therefore, to inoculate
(into the final clarifyer is best) a small amount of B504 and BIO-SYSTEMS B250
blend (about 1kg per month). The B250 will degrade the excess FOG
present in most works due to overload and maintain the desired final
quality.
