The Indian Union territory of Andaman and Nicobar Islands (ANI's) is situated in the Bay of Bengal. ANI is strategically important in terms of national security and geopolitical. Nearly half of ANI’s population resides in Port Blair – with close to 150,000 inhabitants (Census of India, 2011), the municipality is the capital city of ANI and the center for most of ANI's economic activities, being the entry point for tourists and fisheries. Solid waste generated by the floating population like tourists and the defence personnel’s, apart from the native resident population, is a pressure mounting scenario for the Port Blair Municipal Council (PBMC) waste management. A report by Kaladharan et al. (2017) indicates that 47% of ANI solid waste is unmanaged, as compared to the national average of 14%. An affidavit submitted by the Andaman and Nicobar Pollution Control Committee (ANPCC) to the National Green Tribunal (NGT) indicates that PBMC generates about 115 metric tons of municipal waste per day, of which organic waste accounts for 60% (ANPCC 2019). In terms of generated volume, the main organic waste streams identified in the ANI are fish processing waste (FPW), Coconut Shell Waste (CW), Flower Waste (FW), and Saw Mill Waste (SMW). In this regard, a detailed study was commissioned under the Indo-German technical cooperation project Management of Organic Waste in India, to assess the practicality of the uptake/recycling of the main organic wastes in Port Blair, A&N Islands, and contribute to the sustainable waste management in the islands.

Legacy waste dumped over in Brookshabad Dumpsite more than a decade. As per  NGT direction of old dumpsite rehabilitation activities, PBMC  decided to reclaim the land by using bioremediation/biomining Methodology.Tender floated and The Biomining Work was awarded to M/s.Aqua World Exports Pvt Limted, Chennai. 

Methodology

Unscientifically constructed and landfills create irreversible damage to the environment: They generate leachates, emit greenhouse gases, pollute groundwater, etc. A leachate is any liquid that, in the course of passing through waste, extracts soluble or suspended contaminants. It is hazardous in nature. The environmental, ecological and socio-economic implications often make land disposal a menace to be managed. There is an urgent need, therefore, to reclaim the prevailing dumpsites to ensure land availability (referred to as extended landfill capacity) and recycle untapped resources deposited at old dumpsites. Notably, two approaches can undertake to treat legacy waste—or aged waste

1. Scientific capping, which is typically applied to landfills constructed scientifically (engineered landfills/ sanitary landfills).

2. Landfill mining/ biomining, which is a technically assisted and economically managed extraction of recyclables and other revenue-generating fractions from waste materials already been disposed of by land filling.

​Biomining of dumpsites is typically aided by a process called bioremediation. It is microbe-mediated degradation of organic waste carried out by adding biological inoculums to the dumpsite. The guidelines by the Central Pollution Control Board recommend ‘bioremediation’ for the treatment of legacy waste and reclamation of old dumpsites. Bioremediation of legacy waste does not necessarily give efficient results in old / aged landfills (un-operated and closed dumpsites) where the waste has already reached the maximum level of microbial degradation. Therefore, the very first step towards dumpsite reclamation is to analyze the technical parameters such as characteristics and composition of legacy waste for assessing the feasibility of conducting bioremediation of dumpsites.

Biomining (also referred as landfill mining) refers to the process of digging out the previously dumped/ disposed of materials from a Landfill (in our case Open dumpsite) to recover metal, plastic, glass, combustibles, soil and other fine materials. It also refers to clearing the open dumpsites by segregating the prevailing waste into different constituents and converting the biodegradable portion in to compost, and the remaining non-recyclable plastic as refused derived fuels, which in turn can be used as an alternate fuel in Industries. The Compostable portion of the waste is removed through sieving and sold for use as soil enriches/ fertilizer or for landscaping The first step for land fill mining is the stabilization of the existing waste in the dumpsite. Mining of unsterilized or in sufficiently decomposed wastes would result in an unacceptable generation of nuisances and will have a negative impact with regard to the health and safety of the people operating and also affects the ecosystem. The technology mainly targets to excavate the materials and process in such a way that the target materials can be separated from the excavated mass and further process to meet its required grade for any reuse or recycling operations. Generally, excavation is conducted using technologies used for open-cast mining, usually a front-end loader, a backhoe, a clamshell, a hydraulic excavator, or a combination of these. The Excavated material may be directly processed in –situ or will be stock piled for later processing via different methodologies to segregate the components.  Based on the extent of resource recovery, the quantum and number of streams of segregation of the excavated quantum into varies. The process starts with the excavation of materials and the excavated materials are discharged into coarse screens; and oversize, non-process able wastes are removed. The residual fraction is further sent to relatively smaller screens and the material fraction that passes through the second screen is considered as soil fraction.

Further to segregate the soil fraction from the excavated waste, an efficient unit process named trammel screen is widely used. After this, the non-ferrous fraction is processed through an air classifier which separates the light organic materials from the heavy organics and commonly, this is used to recover waste-derived fuel (RDF).

The processing at the landfill site is typically accomplished by means of equipment mounted on trailers, which usually consists of conveyors belts, a coarse screen, a fine screen and magnet separator.  In the final stage after recovery of metals, plastics, etc and combustible materials, the processing rejects and inert is disposed of as a back filling material after confirming its required geophysical properties.

The project must adopt an integrated approach to propose all the activities required for Dumpsite Remediation. It may be detailed as follows:

• Lowest ground level attains.

• Raking of garbage layer through long spike harrow operating in cross directions was done regularly to pull out rags, plastics, rubber, textiles, etc.

• Coarse material and garbage are screened through rotary / horizontal screens.

• The recovered earth is spread in the dedicated area.

• The stone, bricks, ceramics which are removed while screening and raking to be sent for land filling or for filling up of low lying area.

• The recyclables like plastic, glass, metal, and rugs cloth recovered from the waste was bundled and sold.

• The soil recovered to be used for refilling the ground on the same site for greenery.

• The recovered construction and demolition waste sent to C&D processing facility for producing building materials and left over the waste to be sent a secured landfill.

• Valuable land to be recovered by bio remediation process of legacy waste

• The Project Machines to be deployed: -Trommels, Horizontal Screens, Excavator, back hoe loaders, workers.

• Progress of Work to be monitored by a expert team.

 

The remediation of Dumpsite leads to the following advantages:-

• Elimination of foul odor to be refits the citizen living nearby.

• Decline in vector burned is eases arising out of the dumpsite.

• Significant Reduction of air pollution happens of the entire area.

• Elimination of dump fires and leachate generation.

• Up lifting of the environmental, aesthetic and social parameters of entire area.

• Reduction in Green House Gas emissions, Soil Pollution and Ground Water Contamination

• Increase in nearby real estate value and rental values.

• Dumpsite land becomes available for other use.