grundfos biobooster Biobooster cleans up in Norwegian municipality

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1 grundfos biobooster Biobooster cleans up in Norwegian municipality

2 Hemsedal discharges its treated wastewater into the River Hemsil, one of the best-known trout-fishing rivers in Norway. Even when the local population increases ten times during tourist high seasons, the municipality keeps phosphorus and other levels under the strict requirements. Bjørn Olav Viken, Head of Technical Operations at Hemsedal Municipality. Norwegian hamlet solves high-season wastewater treatment problem The challenge is to design wastewater treatment plants in line with seasonal population increases Bjørn Olav Viken, Head of Technical Operations at Hemsedal Municipality. The first municipal wastewater treatment plant in Norway with a membrane bioreactor is ensuring that increased wastewater at a tourist hot spot is efficiently managed and that the vital fishing river remains clean. With skiers, hikers and fishers increasing a Norwegian village s population tenfold during the high tourist seasons, wastewater management is a serious seasonal issue. Hemsedal is a small farming community in the mountains of central Norway. In peak seasons, the 2,300 permanent residents are joined by thousands of outdoor enthusiasts. While they bring a much-appreciated income boost to the small community, this seasonal surge in people also results in a lot more wastewater. Protecting a valuable resource Hemsedal has three treatment plants to deal with the wastewater. In 2008, the municipality decided to refurbish and expand one of them the Ulsåk wastewater treatment plant, originally built in 1982 to cope with the increased load. Plans for the refurbishment also needed to consider how the Hemsedal district s tourist pull comes in part from its good fishing opportunities. In fact, water treated at Ulsåk is discharged into the River Hemsil one of the best-known trout-fishing rivers in Norway. So the need for the plant to meet new treatment requirements was also integral to the local economy as well as the environment. We have very strict rules on the discharge of phosphorus into rivers and waters in Norway. So it was important for us to reconstruct the plant in a way that would protect the watercourse and ensure that we would not contribute to the growth of algae in the river. Bjørn Olav Viken, Head of Technical Operations at Hemsedal Municipality. 2 3

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4 Hemsedal Municipality was an ideal partner to cooperate with. They had wide variations in load and were due to upgrade from mechanical to biological Jakob Søholm, Director, Municipal Segment, at Grundfos BioBooster. Air blowers Chemicals for membrane cleaning Coarse screen Biological process tank Buffer tank Membrane filtration units No bacteria or phosphorus Ingar Nergård, who is responsible for the day-to-day operation of Ulsåk, explains how the 14 horizontal membrane filtration units (MFU) installed in a new building extension at the plant work: After screening materials and sand and fat have been removed the wastewater passes to a basin where a controlled amount of activated sludge is retained. Air is blown into the activated sludge and a biological process takes place. A phosphorous precipitating chemical is then applied before the activated sludge is filtered in the membranes. When we apply the correct amount of chemicals and the aeration works, then phosphorus and organic material remain in the sludge. The filters stop the sludge from being discharged into the river. The discharge is therefore crystal clear at all times, free of bacteria and phosphorus. The water quality easily meets regulatory requirements and there is no adverse impact on the river from the treatment plant. The water quality easily meets regulatory requirements and there is no adverse impact on the river from the treatment plant Ingar Nergård, responsible for the day-to-day operation of the Ulsåk BioBooster plant in Hemsedal Jakob Søholm, Director, Municipal Segment, at Grundfos BioBooster (left), with Bjørn Olav Viken of Hemsedal Municipality inside the BioBooster plant at Hemsedal Norway s first MBR The municipality considered various solutions. One option was to pump the wastewater upriver from Ulsåk to a larger treatment plant at Trøim. But that was going to be too expensive and there were concerns that it might eventually lead to capacity problems at the Trøim plant. Then at a conference on water and wastewater in 2009, a possible solution presented itself in the form of the Grundfos BioBooster membrane bioreactor technology (MBR). And in 2011, the municipality signed a cooperation agreement to set up an R&D project with Grundfos, which had been seeking a partner with which to develop the technology further and test on a full-scale plant. Hemsedal Municipality was an ideal partner to cooperate with, says Jakob Søholm, Director, Municipal Segment, at Grundfos BioBooster. They had wide variations in load and were due to upgrade from mechanical to biological. And so the first municipal MBR treatment plant in Norway was built in Hemsedal, benefitting not just Hemsedal, but Grundfos, too. With the experience we have gained, we have enhanced the actual membrane technology, says Jakob Søholm. PAX tank Sand and FOG removal Fine Screen Ingar Nergård, responsible for the day-to-day operation of the Ulsåk BioBooster plant in Hemsedal

5 Technology supplied by Grundfos BioBooster Pre-treatment equipment for removal of screening materials, sand and fat, oil and grease. Membrane filtration units (MFUs) with a max design capacity of 17 cubic metres per hour. Upgrade of basins for 2,000 population equivalents (PE) biological treatment capacity. New SCADA system. Complete design, installation and commissioning of the new plant. Municipality of Hemsedal Hemsedal is a popular skiing and outdoor leisure resort in central Norway. Approximately 2,300 permanent residents. During high season the population can rise to 20,000. The municipality has three municipal wastewater treatment plants with a total capacity that exceeds 15,000 PE. There are several additional private water treatment facilities in the area. Ulsåk is the first municipality in Norway to build a membrane bioreactor. Four operators are employed on a continuous shift pattern to check the equipment. The load on the Ulsåk treatment plant before reconstruction (2011) averaged 650 PE with individual peaks up to 1,600 PE. The plant has recently successfully managed a peak load of up to 3,000 PE. The treated water is free of bacteria and the phosphorous content is less than 0.3 milligrams per litre. Modular design The flexibility offered by a modular design also appealed to the municipality, with the plant s MFUs turning on and off automatically depending on variations in inflow. Its capacity can therefore be easily increased when necessary, Viken says. It also takes up considerably less space than a conventional plant. We re talking about a simple structure filled with advanced technology. The highly advanced system, which can also be remotely monitored by Grundfos, is also easy to operate. It takes me just three quarters of an hour three days a week to measure the phosphorus level and sludge quality and to clean and calibrate the sensors, Nergård says. Of course, in addition I have to perform periodic maintenance. We re talking about a simple structure filled with advanced technology Bjørn Olav Viken, Head of Technical Operations at Hemsedal Municipality The plant is designed to handle volumes of up to 17 cubic metres per hour. Based on the average for the past three years, we treat around 62,280 cubic metres per year, Viken says. Nergård says that during the start-up phase, frequent checks were carried out. The specialists at Grundfos were there to help us and came up with improvements the whole time, he says. Viken is pleased that the treatment plant is now fully operational with a capacity that can handle more than the peak season demands. Many municipalities in Norway face challenges similar to the one we had. It may be useful for them to consider a similar plant, he says, adding that anyone interested is welcome to visit Hemsedal to study their solution. The specialists at Grundfos were there to help us and came up with improvements the whole time Ingar Nergård, responsible for the day-to-day operation of the Ulsåk BioBooster plant in Hemsedal 10 11

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