Sump

A sump is a tank that resembles a pit or reservoir, usually below ground level and made of concrete. Sumps may have troughs or trenches to collect waste. Sumps are used as secondary containment in areas where hazardous materials are stored and can also be found outside, with access through a manhole cover or grate. If the sump is divided into sections with baffles, it may be an oil/water separation vault. Sump sludge may be hazardous depending on the processes and materials used in the surrounding area.