New Sewer Retention System for municipality of Werkendam

The sewer of Vervoornepolder used to have four overflow channels. One of them was already equipped with a retention tank. However, calculations regarding sewer capacity showed that a new overflow was necessary. To minimize surcharges, the sewer would have had to be extended at various points. Unfortunately, this was not possible for the lack of soil coverage and inclination. Another option was a retention cellar yet this solution would not have met the required capacity. Plans had to be reviewed which led to the conclusion that it would be best not to extend the old sewer but to install a new retention system including new overflows in the surrounding. The new retention system incorporates a pumping unit that pumps all wastewater into the old sewer if necessary. The line feeds through four overflows between the old and the new sewer. With this system, the retention sewer is only active in cases of heavy rainfall. During dry weather conditions or light rainfall the wastewater runs through the old sewer. This creates following advantages compared to an extended sewer system: