The application of this process leads both at the stabilization of ash layers against erosion by initiating and maintaining the vegetation layer and sustaining the ecosystem that is being formed, as well as the recovery of the sludge from the urban water treatment plants.
The problem of ash and slag management is high on the national as well as international level, because the largest share of thermal power plants is occupied by is occupied by those on solid fuel (fossil fuel combustion). From coal combustion result 10-30% by-products, of which the preponderant quantity is ash. The most common and used ash management solution is permanent storage on the ground. Ash deposits and slag contain millions of tonnes of inert, inorganic and nutrient-free material that can not initiate and maintain a vegetation layer, leading to the degradation of the natural biotope. The absence of the vegetation layer on open ash and slag deposits increases their instability at impact with atmospheric conditions (precipitation, wind, temperature differences) leading to environmental pollution in the vicinity of the dump. As such, the restoration of soils in areas where there are slag and ash deposits has become a requirement of the communities in that area.
Formation of the vegetation layer is only a part of the rehabilitation process, because in most cases the maintenance of the vegetation layer and the support of the ecosystem that begins to form in these places are stages of equal importance with the initiation of a culture.
Natural vegetation is generally not sustained because it requires long periods of time and plants that invade the surfaces of these deposits are not agreed, because they are invasive plants, weeds that spread over time on agricultural fields in the vicinity.
Rapid planting of deposits involves stripping with soil vegetal layers requiring additional activity of cutting them from fertile areas, transporting them and arranging the upper layer of ash in a manner that allows the cultivation of some desired plant species. However, the lack of water retention in the upper layers of the slag deposit and ash, even in grounding conditions, strongly affects the vegetation installation, vegetative layers develop poorly.
The disadvantages of the vegetation variants presented above can be removed by applying the grassy plant coating of the ash and slag deposits by fertilizing the upper layers with organo-zeolitic fertilizer.
The recovery process for slag and ash deposits proposed in the invention is carried out in two stages:
• Stage of fertilization of upper layers of slag and ash with organo-zeolitic fertilizer. The proposed organo-zeolitic fertilizer is based on stabilized urban sludge and indigenous volcanic tuff with high zeolite content (clinoptilolite) in the form of the Tuf-Aln type which allows the rapid development of nitrifying bacteria in the porous structure.
The incorporation of the organo-zeolitic fertilizer into the upper layers of the slag and ash deposit it is realizing with traditional agricultural equipment at a depth of 10-15 cm.
• Grassing stage of the fertilized land with the organo-zeolitic fertilizer with maintaining and extending the surface in the following years.
The plant species used are those of the legume and graminee category. Sowing is carried out in a pure culture system at a depth of 3-5 cm. Seeds formed in the first year of culture will determine the extent of the crop and the dead vegetal material contributes to the fertilization of the land by recycling it.The Romanian research institute is looking for companies interested in purchase this technology for commercial exploitation, interested for technical cooperation agreement and for commercial agreement with technical assistance.