The story of Langøya

Langøya has a central place in Norwegian industrial history. Originally it was farming Langøya before Langøen's limestone works were established in 1734. The island's limestone is used for cement production and concrete constructions around the world. The cement companies were also an important basis for industrial development in Norway.

Langøya is today a central part of the infrastructure around Norwegian industry, and ensures proper reception and treatment of industrial waste. The waste collection center was established by the authorities in collaboration with nine major industrial enterprises in 1991 with the aim of putting an end to the release of environmental toxins into Norwegian nature. With dense rocks and deep craters after 100 years of limestone extraction Langøya particularly well suited for landfill purposes. Norwegian industry has delivered on the target, and almost all waste is now delivered for proper reception and treatment.

After almost 30 years of operation, the limestone craters are soon full, and parts of them are Langøya restored and actively used as an outdoor area for Holmestrand's population. Langøya is being developed to become the Oslofjord's next fjord gem.

Limestone mining

Already in the 1650s, the first limestone was taken out Langøya with several lime kilns in operation. In the early phase, the limestone was burnt, and the lime used for brickwork. In 1737 became Langøya limestone works sold for the Danish krone, and from 1899 more modern operations began with extraction of limestone for cement production. Christiania Portland Cementfabrik (CPC) first bought a parcel of land on the island in 1895 to ensure access to good quality limestone for cement production at Slemmestad. The rest of the island was bought in 1899, and the operation of Langøya really got started with shipping limestone on barges to Slemmestad.

On Langøya were built workers' barracks and housing, wharves, dining hall, railway tracks - and Langøya became a community with permanent residents. At most, 24 families with approximately 120 people lived on the island. The children were transported by school boat to Holmestrand. Gradually, the quarries became large, and the operation dangerous for permanent residents. In 1967, the last two families left the island.

Christiania Portland Cementfabrik merged in 1968 with Dalen Portland Cementfabrik and Norland Portland Cementfabrik to form Norcem, with cement factories in Brevik and Slemmestad. Norcem shut down the cement factory in Slemmestad in 1989 and limestone was also taken from Langøya discontinued - after 100 years of operation. 45 million tons of stone had been taken out, and Langøya had two large craters with depths of 60 and 80 meters below sea level.

Waste reception

In the 80s, pollution from industry and the release of industrial acid in Glomma was a challenge. In cooperation with nine major industrial enterprises, the Norwegian authorities established Norsk Avfallshandtering AS (NOAH) in 1991. The starting point was an agreement between Kronos Titan and Norcem from 1989 to neutralize thin acid using limestone from Norcem's old Kalksteinsbrudd on Langøya. Langøya was sold by Norcem/Aker to NOAH in 1993, and has since accepted industrial acid and other special waste from Norwegian industry for neutralization and disposal in the limestone quarries.

Already in 1993, NOAH changed the process where the thin acid was neutralized with limestone to neutralization using fly ash; a basic waste fraction with environmental toxins that must be removed from the cycle. Transition to neutralizing and stabilizing waste with other waste significantly reduced CO2 emissions, and avoids the use of virgin raw materials. Langøya has been the most important reception and processing capacity for Norwegian industry since 1993.

The process chemically binds and stabilizes the heavy metals that are concentrated in the fly ash. The sulfuric acid (H2SO4) reacts with alkalis (CaO) in the fly ash and forms gypsum (CaSO4). The plaster also works to neutralize other waste from the Norwegian process industry.
Langøya had two deep craters from limestone mining; one in the north and one in the south of the island. Between the craters lies the industrial area with processing facilities, wharf and infrastructure for operations. In order to extend the reception capacity, an area in the very south was also blown up in 2019. The craters are defined as a landfill for hazardous waste up to sea level, and a landfill for ordinary waste above sea level. The crater on the northern part of the island is close to completion. The waste reception will end in 2030, and the landfill areas will be completed as open air areas.

Rehabilitation of Langøya

After more than 100 years of extracting limestone and 30 years as a landfill, it is being restored Langøya to one of Oslofjord's natural gems. In the north, the local nature is already in rare bloom, and is an attractive destination in the summer months.

The landfill areas are closed in line with strict requirements from the Norwegian Environment Agency. The waste body is covered with thick layers of local limestone, and a membrane of dense claystone layers to minimize environmental risk. The terrain is designed to provide good water runoff and minimize water penetration. The environment around the waste body and Langøya must be actively monitored for a minimum of 30 years after completion, or as long as the Norwegian Environment Agency deems it necessary.

In close collaboration with the State Administrator and heavy professional circles, the vegetation has been established as open limestone ground on Langøya. This is a rare nature type that naturally belongs in the area, and on Langøya like a limestone island. The natural basis for the vegetation is a poor and nutrient-poor soil, and is already found in the nature conservation areas of Langøya. A thin layer of local soil masses from Langøya is used, and seeds were also taken from the nearby Kommersøya, which has similar vegetation. Natural vegetation has established itself, and several red-listed and rare species such as blue raspberry and star thistle are now flourishing Langøya.

Emphasis has also been placed on the terrain design being varied and providing a good experience for visitors. Landscape architects have imitated the terrain formations from untouched areas.

The northern area of ​​the island is already open to the public. The southern area will be made available by 2034.

Here you can see a selection of historical photos from Langøya.