The Alakorkalo wastewater sludge burning plant in Lapland Finland planned by Napapiiri Energy and Water (Neve) not only promises a more refreshing City of Rovaniemi and considerable savings to its coffers, but other Lappish municipalities could use its services as well. The plant offers a sustainable circular economy solution to wastewater.
Neve, owned by the City of Rovaniemi and consisting of seven subsidiary companies, focuses on power, renewable energy, heating, water supply, maintenance, and optical fibre connection solutions throughout the Finnish Lapland. It has already received the construction permit for the Alakorkalo plant and a government allotment of €1.27 million for the project.
In the lucid wording of Neve Managing Director Kristian Gullsten,
– A sludge burning plant in Rovaniemi would be a local option for treatment and would also allow Rovaniemi to offer its services to other municipalities in Lapland.
He also surmised that the:
– Profitability of the plant largely depends on the amount of sludge in the Lapland area. The largest amount comes from Rovaniemi, but there might be future cooperation with the Kemi-Tornio region and Haparanda [in Sweden].
All the treatment processes under one roof
Currently, Rovaniemi treats its wastewater by burning, rotting, composting or transporting it to a treatment plant elsewhere. Composting is the city’s main way of utilising the sludge. If implemented, the Neve project would replace all these backdated processes and bring all the treatment processes under one roof.
– The burning plant would replace the existing composting plant, affirmed Gullsten. He said the burning of slurry is a more cost-effective alternative for Rovaniemi than, for example, anaerobic digestion and emphasized that transporting the sludge elsewhere is not a local investment and only serves to send Rovaniemi’s euros somewhere else.
The project is being designed by the cleantech company Endev. Based in Southeastern city Kotka in Finland, Endev has already a prototype plant there containing all the components and functionality of a commercial plant. The company uses a process named PAKU for sludge burning which it developed in cooperation with the Lappeenranta University of Technology.
PAKU treats and disposes of municipal sludge using Endev Dryer and Endev Reactor. According to Endev’s website, the PAKU reactor incinerates all organic materials present in sludge, leaving only five to 10 per cent of the original material as clean ash which can then be utilised as an ingredient of agricultural fertilisers.
Endev claims its process is flexible enough to adapt to disparate demographic conditions, as it is capable of producing plants for municipalities with populations ranging from 5,000 to 100,000, which is fine for Rovaniemi, as it has a population of just 60,000.
A sludge burning plant as a solution to harmful substances in wastewater
Although the compost created with wastewater sludge in Rovaniemi has been used in agriculture and landscaping for many years, a growing number of disinfectants like drugs, pharmaceuticals and microplastics, have been detected in sludge in the recent years, said Neve in a press release. Some of these harmful substances end up in the composting biomass.
The press release said, the food industry is particularly concerned about the increase of contaminants in the fertilizers produced from sewage sludge and many operators no longer use such fertilisers in production. This change in scenario has seen the amount of sludge converted into biomass going on the wane and rendering composting no longer a cost-effective option for wastewater sludge processing.
Neve says it is committed to stop that cycle and accumulation of contaminants and harmful substances from wastewater sludge in the ecosystem and the planned Alakorkalo plant is one of its solutions.
– Wastewater sludge contains contaminants, most importantly phosphorus, which can be processed out and recycled in the form of ashes as fertilizer, said Gullsten.
He also pointed out that:
– In the treatment and processing for sale of sludge burning, an existing granulation plant can be utilised where the whole chain from production to dissemination is ready and Neve already has an abrasive granulation plant in use at its Suosiola power plant in Rovaniemi, where the ash from the sludge burning could be utilized in conjunction with the ash from the power plant. The combustion of sludge would destroy the harmful substances that have been drawing objections from the quarters concerned. Besides, the combustion will also generate some energy for Neve’s district heating network.
The environmental permit application in process
According to the Neve press release,
– The environmental permit application for construction of the plant has already been submitted to the licensing authority… Realization of the actual investment will be achieved after the authorization process has been approved. The [cost of the] total sludge incineration plant is about EUR 4.3 million.
Neve in its environmental permit application stated that beyond the first year of the operation (the test period), the plant’s air emissions might exceed the limit values. However, once the plant is optimized, according to company models,
– Sulphur dioxide, nitrogen dioxide and particulate matter in the air are very low. The concentrations fall below 1% of the current guidelines and limit values. Also heavy metals, dioxins and furan concentrations are low and clearly below the guidelines and limit values as well as the target values.
Talking on the possible environmental impacts of the plant, Gullsten said, “There are potential odour emissions,” but that would not vary significantly from the current state of odour emissions from the composting facility. There would also be no significant changes in noise levels, vibrations or the soil quality due to the plant, and the environmental impact of transporting sludge away from Rovaniemi would be lessened, he added.
In terms of investment, €1.27 million has come so far under a government project named “Bio-Economy and Clean Solutions: A Breakthrough in the Turnover Economy and Clean Solutions for Use.” In this regard Gullsten said,
– Investment in the plant would be related to the circular economy, the wastewater nutrient cycle, and resource and material efficiency. At this point, it is difficult to say what the investment costs of the incinerator would be in the future. This is significantly affected by the interpretation of sludge combustion as waste incineration, whereby, for example, continuous measuring devices are required for emissions monitoring, and the limit values are considerably stricter than similarly sized solid fuel boilers, he explained.
However, regulations could change, quipped the CEO. – If sludge regulation is changed or shifts closer to fertiliser regulation, it could have a significant impact on the matter, he added.
On the possibility of using sludge as a raw material for renewable energy, Neve says 56.8 per cent of the heat production on its grid comes from renewable sources, including wood chips, wood, biogas, and fuel pellets (from wood), but wastewater sludge is regulated as waste and not a renewable resource, and the new sludge burning plant will be considered a waste incineration plant. That’s why the energy produced from burning sludge will not have a significant impact on energy production for the Neve grid.
The employment opportunities to be generated by the plant would depend on the scale of its operations, transportation of sludge from other municipalities and related activities, as well as handling and transport of the processed ashes, said a source at Neve.
Interested in circular economy in Lapland?
Read also about: