It is costly for municipalities when sanitary sewer overflow (SSO) occurs. SSO can happen in a residential, commercial or institutional building, as well as in a street or an environmentally sensitive area. The costs of cleaning, damages, noncompliance and possible litigation are daunting. Mechanical inline flapper and swing check valves are sometimes used to stop SSO in gravity sewer lines. However, they have an inherent inability to close off against sewage debris.
Water storage tanks and reservoirs are a critical component of distribution systems, yet they can pose a significant challenge for water utilities as they often have a negative impact on water quality. Water quality problems can develop due to low turnover and/or inadequate mixing resulting in short-circuiting.