Technology for reclaming wastelands
We provide expertise in greening and reclamation of wasteland to turn it into green, productive land. We do this using a beneficial group of micro-organisms known as Mycorrhizal fungi. Successful examples of sites reclaimed using this technology include fly ash overburdens, alkali chlor-laden sites, distillery effluent discharge sites, phosphogypsum ponds, coal mines, red mud, saline and arid sites.
Case Study 1: Phytoremediation of Fly ash Dykes
When coal burns, it produces fly ash—fine solid particles of ash, dust, and soot containing lead, arsenic, cadmium, cobalt, silica, mercury, and other toxic elements. The bulk of fly ash generated in thermal power plants, has been disposed of by wet and dry methods. In dry disposal, the fly ash is dumped in landfills and fly ash basins. In wet methods, the fly ash is washed out with water and piped as slurry into artificial dams, lagoons or settling ponds. This ash is often referred to as pond ash and over time the water is allowed to drain away. Both methods effectively lead to dumping of the fly ash in landfills on open land. It becomes a deadly source of health hazards when carried into the atmosphere by wind and to the hydrosphere and biosphere through leaching and surface run off. When thermal power sectors were clueless about how to cope up fly ash hazards, researchers at TERI came up with the mycorrhizal technology. Different strains of mycorrhizal fungi were collected from diverse regions of India and abroad. These were then isolated, selected, multiplied, and tested under greenhouse/nursery conditions to find out their growth pattern on fly ash dumps. Strains offering high tolerance, assisting in survival, and providing nutritional support to plants were selected for the purpose. With additional doses of organic and mycorrhizal fertilizer to optimize the impact, the mycorrhizal strains were then applied with selected plants (poplar, sheesham, eucalyptus, neem, vetiver, lemon grass, Jatropha, etc.) on fly ash dumps. And, when put to application, life sprouted on grey, degraded, toxic wastelands in the form of green vegetation. In the long run, such green vegetation unfolds a series of physiological changes through bio-geo chemical cycle leading to enrichment of the surface and subsurface ash to promote natural ground cover.
Case study 2: Reclamation of Chlor-alkali sludge-laden Wasteland
The chemical wastes formed out of alkali- and chloride-rich sediments from industrial discharge of Tata Chemicals were posing a health hazard for the residents of the areas nearby. Due to high wind in coastal areas, those sludge particles blown away from the dump site to nearby residential areas causing breathing and skin problems, decolorization of clothing, and even heavy corrosion of metallic structures. The site had extremely high pH (11.7) and electrical conductivity (74.4 ms/cm2) and was devoid of any vegetation. Moreover, sweet water scarcity in those coastal areas worsened the condition drastically. In spite of such environmental stresses, a few microbes were found to sustain there. When those microbes were isolated, mass multiplied and finally applied along with micorrhiza, they showed excellent result. Even, oil seeds, planted during earlier unsuccessful trials, started germinating. Although, initially irrigation was carried out with sweet water but after a few days, surprisingly all the plants(e.g., Salvadora persica, Thespesia populnea, Casuarina, Perkinsonia) were able to withstand sea water. Moreover, establishment of such vegetation significantly changed the physicochemical properties of substrate such as pH, increase in organic matter, N and P. Significant alteration in substrate properties resulted in natural establishment of native grass species in and around the study site.
Case study 3: Reclamation of wasteland laden with Distillery effluents
Distilleries generate huge amount of organic rich effluent and when it is dumped into low land areas, it causes percolation of pollutants to nearby fields, damage soil texture and health, and lastly results in ground water pollution. Associated Alcohol and Breweries ltd of Barwaha, Madhya Pradesh (MP), was facing such type of problem with their six-year-old effluent dumpsite. Due to that dumping site, the colour of ground water in neighbouring villages got changed, during monsoon nearby lands got flooded with effluents, and an intolerably foul smell from the site perpetually hung in the air. Beside that the organic sludge deposited in the dumping site had alkaline pH (9.4) and very high salt content (EC 34.4 ms/ cm2). When mycorrhiza mediated High Rate Transpiration System (HRTS) was applied to that dump site, it changed to a lush green landscape. HRTS is a land application system where effluent from breweries is disposed in a specially designed landscape with wide ridges and furrows, and mycorrhiza-mediated trees that are bestowed with high transpiration capacity.The mycorrhiza was selected on the basis of physico-chemical properties of the effluent loaded soil that was used for ridges preparation. Application of certain species of mycorrhiza along with HRTS technology made that site a commercially viable area with economic plantations such as Bamboo, Glarcidia, Guava, Mahaneem (Melia azedaarach), and bio-diesel species like Jatropha.
Case study 4: Production of green vegetable in hypersaline
Desert land through mycorrhiza technology The hyper-saline area of Dukhan, located in the western part of Qatar has extremely adverse land and water conditions making farming difficult. Moreover, the climate is hot subtropical characterized by hot humid summers and semi short winters with scanty and infrequent rainfalls. The soil salinity level is very high and accumulation of white salts (soluble chloride and sulfates of Ca, Mg, Na, and K) on soil surface (white encrustation) is a common phenomenon. When mycorrhiza-based organic farming was applied to that area it changed to a productive land having plantations of tree species such as Cerus, Casuarina, Melia, Parkinsonia; Amla (Phyllanthus emblica), Jatropha, Babool, Albizia; ornamentals like Bougainvillea, Portulaca; medicinal plants such as Vetiver, Mint, Basil; vegetables like Brinjal, Chillies, Okra, Drumstick, Melon; grasses and legumes like Rhodes grass, Bahia grass, Sudan grass, Sorghum, Alfalfa, etc. Beside that adaptation of such simple, farmer and eco-friendly practices resulted in enhancement of soil organic matter, improvement of pH, reduction in soluble salts (chlorides and sulfates), establishment of microenvironment for beneficial soil microbes, appearance of earthworms in plant basin and other ecosystem components such as birds, insects, snake, lizard, and rabbits.