Combined Sewer Overflow

Municipalities are being challenged to eliminate all discharges of untreated wastewater caused by Combined Sewer and Sanitary Sewer Overflows (CSO & SSO).

Of primary concern are that CSO and SSO events contain particulate and soluble wastes from domestic sewage, industrial and commercial wastewaters, as well as storm water run-off.

These waste products include suspended solids, bacteria, viruses, nutrients, toxic pollutants, oil and grease, and debris. Significant risks to receiving water quality, public health and aquatic life can occur due to CSOs and SSOs.

Chronic CSO and SSO events are caused by a number of factors, including wet weather inflow and inflitration, undersized sewer lines and pumping stations, pipe bursts/blockages and deteriorating collection systems.

All of these serverely strain and ultimately overload the downstream Wastewater Treatment Works (WwTW), causing discharges with little to no treatment.