What are the advantages and disadvantages of a separate sewer system?

Merit

• Sewage is separated from rainwater and is treated at a water reclamation center, so there is no outflow of sewage to rivers or the sea.
• Where existing waterways can be used, construction costs can be reduced because only sewage pipes can be laid.
• The capacity of the sewage treatment facility can be small because it covers only sewage.

Demerits

• In the place where two sewage pipes and rainwater pipes are laid, the construction cost is higher than the combined type, where roads are narrow or where they compete with underground buried objects of other businesses such as gas pipes and water pipes Is also difficult.
• In the early stages of rainfall, dirt and air pollutants attached to the road surface are washed away and washed away along with rainwater into rivers and seas.
• If rainwater or groundwater enters the sewage pipe joints or manholes, or if residential land drainage or road surface drainage is accidentally connected to the sewage pipe, it may result in excess of the drainage capacity and sewage treatment capacity of the pipe. .