Innovation provider

Institute of Mechanised Construction & Rock Mining


Racjonalizacji 6/8, 02-673 Warsaw, Poland; Phone number: +48 22 843 02 01, Fax number: +48 22 843 59 81; e-mail: Website:


Sewage sludge from the sewage-treatment plants constitutes a problem that requires urgent solution. It is a serious threat to the environment. A new method of sewage sludge utilization has been developed in the Institute. The end product of the thermal process is a commercial one – meaning safe lightweight aggregate and not, as up till now, dangerous stored ash. It raises the profitability of this method, which varies from the ones currently used and based on vitrification with applying lower temperature in the thermal process. The next step of increasing the profitability of this method is the usage of industrial and communal waste in the aggregate production. The granulate is being made from the mixture of non-treated sewage sludge, rock mining and mining waste, glass cullet, debris from bricks or tiles. The granulate baked up to 1100 °C creates a sinter with the properties of lightweight aggregate, analogous to the properties of the well-known keramsite. It is essential to notice, that as a result of baking the heavy metal compounds from sewage sludge are built in the crystalline structure of silica sinter. They are unwashable and safe for the environment. Tests of the dangerous substances elution performed for the aggregate produced from the sewage sludge in Września and from the chalcedonite ashes in Inowłódz confirm that the amount of heavy metals in aqueous extracts according to PNEN 1744-3 standard has decreased. The artificial lightweight aggregate being the result of the process easily fulfilled the basic requirements of PN-EN 13055-1 and 13055-2 standards.


The main ecological effects of the method are:
- lowering energy-consumption of solidification process
- the basis for costs reduction,
- complete stabilisation of dangerous substances,
- the possibility to obtain a commercial product from the waste,
- use of the industrial and communal waste in aggregate production.

Innovative aspects (ecologic, social and economic)

Application examples




Current stage of development

Entering the market 

Intellectual Property Rights

Patent applied for
Patent Application No. P 384611

Country of origin


Country of application



National Contact Point

dr Włodzimierz A. Sokół
National Contact Point for Eco-efficient Technologies and Management Systems
Central Mining Institute (GIG)

Plac Gwarkow 1
40-166 Katowice

Tel: +48 32 259 22 11
Fax: +48 259 22 11