Determining the type of drainage

An overview of the options

Wastewater is channelled to the sewer via a natural gradient. — A free gradient to the sewer is generally advantageous.
RSE: Backwater level

The outlet is located below the level of the sewer. — If the sewer is higher than the drain outlet, the wastewater must be "pumped up".
RSE: Backwater level

The position relative to the channel determines the type of drainage

Wherever possible, a sufficient gradient towards the sewer should always be ensured for drainage via a backflow prevention system. This allows wastewater disposal to occur by gravity without the need for additional pumping, resulting in significantly lower investment, operating and maintenance costs.

If wastewater needs to continue to be disposed of during a backflow event, a hybrid drainage system (backwater pumping station or hybrid lifting station) can be used to switch to pump operation if necessary.

A free gradient to the sewer is generally advantageous.

If gravity drainage is not structurally feasible, the wastewater must be conveyed to a backwater loop using a conventional lifting station, from where it can flow towards the sewer. A separate backwater valve is then not required for the drainage points connected to the lifting station.

Open-channel drainage with an unobstructed pipe cross-section. — Normal operation:
Drainage via the natural gradient

A closed flap prevents water from entering from the drain. — Backwater protection:
A closed flap prevents water from entering

Gravity drainage with a backwater valve

Open-channel drainage with an unobstructed pipe cross-section. — Normal operation:
Drainage via the natural gradient

A closed flap prevents water from entering from the drain. — Backwater protection:
Backflow prevention prevents water ingress

Wastewater is pumped into the sewer against the backwater pressure. — Drainage in the event of backwater:
Pump operation against backwater pressure

Gravity/pressure drainage with a backwater pumping station

Hybrid lifting stations for drainage via natural gradient to the sewer — Normal operation:
Drainage via the natural gradient

In the event of backwater, the hybrid lifting station prevents backflowing sewage from the sewer from entering the system. During drainage via a natural gradient to the sewer — Backwater protection:
A backwater valve prevents water from entering

In the event of a backflow, the hybrid lifting system prevents backflowing sewage from the sewer from entering the building and pumps it via the backflow loop to the sewer to drain the building. — Drainage in the event of backwater
Via a pump through the backwater loop

Gravity/pressure drainage with a hybrid lifting station

A schematic diagram of a pumping station that pumps wastewater into the sewer via the backwater level. — Normal operation:
Drainage via the backwater loop

A schematic diagram of a pumping station that prevents water from entering the building via the backwater loop during a backflow event. — Backwater protection:
The backwater loop prevents water from entering

A schematic diagram of a pumping station that pumps domestic wastewater into the sewer during a backflow incident. — Drainage in the event of backwater:
The system continues to operate as normal

Permanent pressure drainage with a lifting station

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