Wastewater Networks Go Smart: Monitoring Extraneous Water in Levanger's Sewage Network

Extraneous water can add a considerable strain on wastewater systems and treatment plants, leading to higher operational costs and even causing sewage overflows. To manage extraneous water in its wastewater network, Levanger Municipality in Norway has started a trial project using Pipelife's sensor-based technology. The project has allowed Levanger to pinpoint areas of extraneous water infiltration and take targeted action, reducing wastewater management costs and improving the overall network efficiency.

_{What is Extraneous Water?}

Extraneous water, also called excess or foreign water, is water that has entered a sewer system but does not belong there. The most common causes of extraneous water are groundwater infiltration through cracks and crevices, illegally discharged stormwater, and rainwater entering sewage canals through manholes.

As extraneous water does not require the same level of treatment as wastewater, it imposes an unnecessary hydraulic load on sewer networks, pumps and treatment plants, leading to considerable additional costs to operators. In the worst-case scenario, high amounts of extraneous water can lead to sewage overflows.

Areas with high precipitation levels are particularly prone to extraneous water, and studies have shown that infiltrated water volumes in the sewer system can reach up to or even exceed 100% of wastewater volume. 

Sewer flow monitoring is crucial to identify leaks, optimize network maintenance and rehabilitation and reduce extraneous flows, bringing down wastewater management costs.

_{Smart Extraneous Water Detection System in Levanger}

Levanger Municipality, located in central Norway and home to around 20,000 residents, is planning to build a new wastewater treatment facility. To prepare for this investment, the municipality needed to evaluate the excess water volume in its sewage system and address leakages.

After learning about Pipelife's sensor-based solutions last year, Levanger decided to join a trial project to monitor the composition of the wastewater and locate where the leaks are occurring in the network — whether from stormwater or seawater intrusion. 

Due to on-site inspections performed previously, the municipality had already identified an approximate area with high leakage rates. The goal of the trial project was to pinpoint the leaks and devise the necessary rehabilitation measures to optimize the network's performance.

"We were aware of leaks in this area, and when presented with the opportunity to spot the exact locations within the network, including which manholes were compromised, we decided to test Pipelife's sensors," says Bjørn Sandvik, Head of Water and Wastewater Department at Levanger Municipality.

^{Comparing Data: How it Works}

Ten sensors measuring water level, flow rate and temperature were installed in Levanger's sewage network in the spring of 2024. Collecting water flow and temperature measurements during the dry season provided Levanger with valuable baseline data, enabling comparison with changes in wastewater levels once the rainy season began. Analyzing differences in both data sets has allowed the municipality to identify several leaking manholes and pipes within the network.

"With the dry period behind us, we had accurate temperature measurements and baseline data for our network when it only contained wastewater. The recent heavy rainfall has given us additional data to work with," explains Sandvik.

_{Reducing Extra Strain}

The project has been successful in detecting and reducing extraneous water infiltration in Levanger's sewage network. Pipelife Norway continues working closely with the municipality, and it's expected that even more network weaknesses will be identified in the future. 

By monitoring water levels and identifying areas where unwanted rainwater has been entering the system, the municipality can now take targeted action. This proactive approach will help minimize unnecessary costs and resource consumption, offering Levanger's community an optimized wastewater management service.

Monitoring extraneous water in sewage networks allow municipalities to identify leaks, optimize maintenance and rehabilitation tasks and reduce foreign flows, bringing down wastewater management costs.