From Sludge to Biosolids to Organic Fertilisers – Norway’s Experiences over the Past 20 Years
Tornes, O.1 and Whipps, A.2, 1IVAR IKS, Norway, 2Pell Frischmann Ltd.
(free)
Abstract
IVAR IKS, the regional organisation responsible for the provision of drinking water and wastewater treatment in the Jaeren region of Norway has pioneered innovation and technical development of sludge treatment and subsequent recycling.
As a consequence of the development of the Norwegian oil and gas industry, Stavanger, the population centre of the Jaeren region, has seen unprecedented growth over the past 20 years with both industrial and commercial expansion supporting a significant growth in population.
Although Norway is not part of the EU, full cognisance of EU Directives is taken and stringent environmental regulation is enforced throughout Norway. Against this backdrop of environmental awareness and regulation IVAR IKS developed the first regional wastewater treatment facilities in the 1990’s close to the harbour at Mekjarvik.
Sludge treatment facilities included anaerobic digestion and the first thermal drying process in Norway. Despite a number of operational difficulties with the original pelletising plant IVAR IKS persevered and continue to operate thermal drying plant to this day. Extensive agronomic trials for the development of a biosolids-based organic fertiliser has resulted in the production of MINORGA available in big bags for agricultural use in Norway and export to the Far East. Future regulations are likely to pose further challenges at a time when population growth and expansion of the waste water treatment facilities will generate even more biosolids. The most challenging amendment to the new regulations is related to the phosphorus supply when biosolids are used on agricultural land. Due to national focus on biogas production, there is an increasing interest in treating wet organic waste in digestion facilities. As a part of this development IVAR was the first company in Norway to offer the receipt of untreated food waste from institutional households and retail stores for the production of biogas. This has enabled IVAR to increase the biogas production considerably for cost effective use in the adjacent natural gas system. In this context, IVAR was also the first company in Norway to introduce the amine based scrubber technology for this purpose. Purification of biogas to natural gas standards and its distribution through the natural gas systems as fuel for public transport are likely to be the future key market in the Stavanger region. A second regional co-digestion plant located at Grødaland in the southern part of the region is currently under construction and scheduled for commissioning early 2016. The plant will offer a complete treatment of sludge, source separated food waste from private households, care homes and retail stores. This will ensure treatment capacity and flexibility in accordance with the future development of housing in the region.
The paper looks back to commissioning of the initial thermal drying plant in 1992, traces the development of processes and products and looks to the future regulations and environmental obligations in Norway.
Introduction
The Jaeren region of Norway has developed significantly since the humble days of fishing from the relatively small coastal settlement at Stavanger. The innovative spirit flourished with the introduction of mechanised canning systems and the development of highly successful sardine and herring industries.
Since the discovery of the Ekofisk oil field in the North Sea in 1969 , the Jaeren region has gone through an extensive industrial and commercial development. The region has continued to rise to the challenge of innovative development and has seen unprecedented population growth over the last 20 years. The densely populated Stavanger/Sandnes area is Norway’s third largest urban area however it boasts one of the largest single waste water treatment works in Norway. Due to the pressures of population growth and tightening discharge quality standards, waste water treatment is an important topic for a nation proud of their environmental responsibilities.
Keywords IVAR, Norwegian Water, biosolids, thermal drying process, pelletiser, fertiliser, MINORGA
