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      Tertiary Biological TreatmentA sketch of a typical wastewater treatment system that provides primary treatment (e.g., settling or clarification) plus secondary biological treatment (activated sludge) and...
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      Waste Stabilization Pond System (overloaded)This is an example of an optimal waste stabilization pond system, consisting of a 1-day, 3-m deep anaerobic pond followed by a 3-day, 1.5-m deep facultative pond, with treatment...
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      Waste Stabilization Pond System (optimal)This is an example of an optimal waste stabilization pond system, consisting of a 5-day, 3-m deep anaerobic pond, a 15-day, 1.5-m deep facultative pond, and a 20-day, 1-m deep...
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      Secondary Biological TreatmentA sketch of a typical wastewater treatment system that provides primary treatment (e.g., settling or clarification) plus secondary biological treatment (activated sludge), with...
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      Primary TreatmentA sketch of a typical wastewater treatment system that provides primary treatment only (e.g., settling or clarification), with sludge treated in a drying bed for 180 days.
