Swedes cheer teamwork, savings in pressurized wastewater network

Much of the area is also in a water protection zone. Swedish law was moving toward requiring all homes in such areas to connect to both municipal water and wastewater networks. Homeowners outside city limits would have to finance and build their own lines, however.

“The municipality would not assume such a responsibility, so it was up to the property owners to solve this problem,” says Jan Magnusson. At the same time, the municipality’s requirements for sewage removal from all properties were strict. Therefore – as is common all over Sweden – Kållands VA formed to tackle the challenge as a group, he explains.

In 2006, it connected water lines from all properties to the municipal utility. The homeowners knew the municipality was going to pressure them for sewage removal, too. So in 2012, Kållands VA decided to add wastewater – a more challenging undertaking.

“We didn’t know the project would be this large when we started,” says Jan Magnusson. “It grew along the way. More and more people got interested as we went along. In the beginning we were just talking about 260-280 properties. We finished with about 670. It was an incredibly large project, indeed,” he says. “And all together we solved the problem. In cooperation with Grundfos, of course.”

The solution

Kållands VA asked Grundfos to supply wastewater pumps, but the company did more than that, Jan Magnusson says.

“Grundfos mapped the system and dimensioned the network,” he says. “They made a design for every part and leg, and divided the network into smaller legs. Then they made a map of the entire system and suggested the intermediate pumping stations. And then, of course, the size and dimensions of pumps and pipes.” 

Grundfos specialists at the Grundfos Water Utility Competence Centre used an advanced hydraulic tool called SIMPS – which stands for Simulations of Pressurized Sewer Networks – for sizing and dimensioning the pumps, piping and pumping stations. Grundfos supplied Prefabricated Pumping Stations (PPS) at 530 locations plus 16 larger, intermediate PPS for network pumping stations. In the end, the design incorporated 130 kilometres of piping.

The SEG AutoADAPT grinder pumps in the smaller PPS eliminated the need for extra pump controllers, switches and extra cables, since everything was included inside the pump. This cut installation time in half. “We reduced the overall installation cost by 50%,” says Kjell Asplund of Grundfos Sweden.

The intermediate PPS network stations used SEG and SLV wastewater pumps from 4 kW to 11 kW. This design – with 16 intermediate PPS and small to medium-sized pumps instead of just a few very large pumping stations with high-kilowatt motors – helped to reduce operational costs and energy consumption, he adds.

“It meant that each household could use the smallest pump size possible. And then the smaller pumps in the intermediate PPS saved energy compared to a few PPS with large pumps,” he says.

The outcome

It took the association three years to finish the project. “We’ve had very few problems in starting up all these areas,” says Jan Magnusson. “We’ve had very few stops. It’s been incredibly painless to start up the whole thing."

As for the equipment, he adds, they are not complaining.“Right now we’re servicing all the pumps under the guarantee warranty, and we’ve gone over the first nearly 200 pumps. We have not found a single pump with a fault. All of them have been completely fine after working for three years. We consider that really good.”

System design consultancy, including SIMPS software modelling, mapping and dimensioningEquipment, including

• 530 standard Prefabricated Pumping Stations (PPS) in polyethylene

• 5 double PPS in fiberglass

• 11 double PPS in polyethylene

• SEG AutoADAPT sewage grinder pumps for standard PPS

• SEG AutoADAPT sewage grinder pumps for network PPS

• SLV wastewater pumps for network PPS- Dedicated Controls
• CIU 252 (communication units)