The construction of a sludge treatment facility at Vilnius’s wastewater treatment plant addresses a number of environmental challenges at one stroke, while improving the quality of life of more than 590 000 local residents. The sludge pellets produced by the new system also have potential use as a fuel source for greener energy.
- 17 November 2014
Development of the facility sorts out problems created by the excessive production of sludge at the treatment plant, including pollution of soil and underground water sources, emissions of greenhouse gases and the spread of sewerage odours across the city.
In addition, the project reduces the quantity of sludge discharged into regional landfills significantly. This, in turn, helps to extend the economic life of the landfills and cuts down on the costs of transporting and disposing of semi-liquid sludge.
Versatile end product
The new facility which has been operational since 2013 produces about 13 565 tonnes of dried sludge pellets every year. It takes in sludge from the Vilnius wastewater treatment plant along with additional amounts transported in from neighbouring municipalities.
At some point in the future, the pellets – which have a high calorific value – could be burned in a waste-to-energy power plant. At the moment, such a plant does not exist in Vilnius, which results in the pellets being stored on site in an area used for sludge composting. Some of the dried sludge can also be composted and used as a fertiliser, for agriculture and reclamation.
Proven technology
The sludge treatment process harnesses commonly used and well-proven treatment techniques and stages, including primary thickening, the pre-treatment of sludge through thermo-hydrolysis, digestion accompanied by co-generation of energy from biogas, final extraction of water by centrifuge, and a belt-drying phase.
To ensure reliable performance of the treatment facility, some existing equipment has been upgraded. The equipment changes also allow for a greater reduction in the organic material collected through the preliminary treatment stage, along with more stable separation of biological surplus sludge and its supply for treatment.
Total investment and EU funding
Total investment for the project “Sludge Treatment Facility at Vilnius Waste Water Treatment Plant” is EUR 63 335 021, of which the EU’s Cohesion Fund is contributing EUR 28 968 897, from the Operational Programme “Promotion of Cohesion”, for the 2007 to 2013 programming period. Work falls under the priority “Environment and Sustainable Development”.