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City of
Aberdeen
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Industrial Pretreatment Program
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Treatment Process (Part 2) The process is broken down into four areas. ● Pretreatment/Primary Treatment ● Secondary Treatment ● Final Treatment and Disinfection ● Solids Handling Final treatment once again involves clarification. The “dirty water”
from the aeration basins is allowed to settle in the final clarifiers
and the solids (the microorganisms) are settled out. Some of the
organisms are returned to the secondary treatment system to replenish
the supply of “bugs” and the rest of the bugs are “wasted” to
the solids handling (or digester). The treated wastewater is then disinfected and then sent to Moccasin
creek. At this point, over 95% of the suspended solids and over 90% of
the oxygen demanding pollutants have been removed from the water. Solids handling, better known as sludge digestion, uses anaerobic
conditions in order to produce biosolids that are put on farmers fields
as fertilizer. The picture below demonstrates the benefits of using biosolids for
fertilizer. The near portion of the picture did not have sludge applied
to it The far side did. The grass is much thicker and darker where the
biosolids were applied. |
