Under pressure from the state Department of Environmental Protection, the Altoona Water Authority is planning a program to determine whether pollution from its two Combined Sewer Overflow systems is problematic. CSOs were once commonly installed in cities, but were never ideal, because they collected both sewage and street runoff in the same pipes, so that when there were storms, and the volumes became too great for the pipes and sewer plants to handle, the excess carried sanitary sludge residue that had settled in the pipes during dry weather into the streams, polluting them. Under ...