The D.C. Water and Sewer Authority recently scrapped a massive upgrade to its wastewater treatment capability after the projected cost soared by $250 million in one year.

The “egg-shaped digester” was the District’s proposed new method for handling the 1,300 wet tons of “biosolids” — the remnant sludge of the wastewater treatment process — that emerge daily from the 150-acre Blue Plains Treatment Plant. The plan was to build eight, 108-foot-tall, 4.5 million gallon digesters. Once operational, they would cut the biosolid volume in half, limit the stench that wafts from the plant and drastically reduce the number of trucks required to haul the sludge away — saving more than $16 million a year.