The specialised technical journal CompostPro (No. 5, August 2024) has published an article on geotubing technology used at sludge drying beds in Kazan. The article describes the specifics of the method.
The key elements of the technology are large geotextile containers GEOTUBES (СТО 56910145-016-2015) – highly efficient filtering woven systems made of geosynthetic material that retain, for example, sludge inside while water passes through their walls.
The cost of the work was an important factor in selecting the technology for the reclamation of the sludge drying beds. Geotubing offered a balance between quality and cost. After the project was selected, design and cost-estimate documentation was prepared and passed the State Environmental Review conducted by Rosprirodnadzor. Both the project itself and its implementation technology passed the review.
The technology involves pumping raw sludge, together with reagents that bind mobile forms of metals and provide disinfection and sludge stabilisation, into a geotube — a container made of polymer fibre with micropores. Sludge dewatering is achieved by physically «squeezing» moisture out of the bag. The sludge is stored in the geotube for at least one year. During this period, biological composting and chemical neutralisation take place more effectively than under conventional storage conditions at landfills. Storage in a geotube also significantly reduces the volume of sludge through natural dewatering.
The tasks addressed by geotubing technology:
- sludge dewatering;
- disinfection;
- neutralisation — reducing the level of heavy-metal contamination;
- the possibility of processing directly at the site where the sludge is placed, on the sludge drying beds;
- neutralisation of harmful odours.
