Waste Water Treatment

When raw sewage comes into Blue Plains debris and grit are removed and trucked to a landfill. (Rosanne Skirble/VOA)

Sewage flows into primary sedimentation tanks that separate more than half of the suspended solids from the liquid. (Rosanne Skirble/VOA)

After primary sedimentation, the fluid flows into secondary tanks where oxygen is pumped into it so microbes can break down the organic matter. (Rosanne Skirble/VOA)

In a laboratory at Blue Plains, researchers are working on a cost-saving measure that would deploy a newly discovered microbe that can break down organic matter without oxygen. (Rosanne Skirble/VOA)

Blue Plains plans to cut its nitrogen discharges into the Potomac River by half when this expansion project is completed in 2014. (Rosanne Skirble/VOA)

Microbes convert ammonia into harmless nitrogen gas. (Credit: DC Water)

Water, percolated through sand filters, removes remaining suspended solids and then is disinfected and de-chlorinated and discharged into the Potomac River. (Rosanne Skirble/VOA)

Construction is underway to build giant digesters that will bake the solid waste recovered during treatment and turn it into methane gas that will in part power the plant. (Rosanne Skirble/VOA)

Wastewater cleansed at Blue Plains is cleaner than the Potomac River when it is discharged in the waterway. (Rosanne Skirble/VOA)

By 2025 a new underground tunnel system will reduce to almost zero sewage overflow into Washington, DC waterways. (Credit: Ted Coyle, DC Water)

The system of pipes, valves and pumping stations that distributes water to more than two million people in Washington, DC and suburban communities is aging like this one installed in 1910. (Credit: DC Water)