An aerial view of the Solid Waste Management Facility at Calangute.
Graciously Accepting Refuse
Perched on the top of the Saligao Plateau in Goa, the Solid Waste Management Facility operated by M/s Hindustan Waste Treatment Pvt. Ltd. has been graciously accepting solid waste and garbage from the surrounding areas and treating it for the past one year.
The Facility is unique
The Facility, which was officially inaugurated in May 2016, is said to be one-of-its-kind in Asia and one visit to the plant is enough to prove this. Can you imagine sitting peacefully and enjoying a cup of tea in the midst of a garbage treatment plant which treats 100 tonnes of solid waste day in and day out? Well, that’s possible here!
The design, construction, equipment and management have all been carefully worked upon so that problems of odour, human intervention, unsightly garbage mounds and leachate generation are all addressed.
The state-of-the-art facility is based on mechanical-biological treatment, which ensures that maximum material and energy is recovered from the garbage. In fact, only a very small component (~10%) of the garbage is permitted to be land-filled by the Company, which is in stark contrast with the conventional garbage plants that usually resort to nothing but dumping.
The Treatment Process
The Treatment process basically takes place in three parts:
1. Material Segregation and Recycling Section – For Dry Waste
2. Wet Waste Treatment Line (via Bio-methanation and Composting)
3. Landfill area for inert waste
• The garbage supplied in trucks/rickshaws by the adjoining local bodies is unloaded on the tipping floor, after which it is mechanically loaded to a chain Conveyor Belt. A bag opener is present to open any bags which might be present in the garbage.
The garbage then passes through a mechanical roller screen which sieves it into larger and smaller fractions.
• The larger fraction (overflow) moves to the manual sorting station, where different fractions from the dry waste (such as paper, tetra pack, bottles, plastic bags, hard plastics, cardboard) are sorted out. The separated fractions are baled and stored in Containers, after which they are sent for recycling.
• The remaining non-recyclable waste is baled (compressed) and sent to Cement Companies where through a process called co-generation, it is used as a fuel along with coal in the manufacturing of Cement.
• The smaller fraction (underflow) is passed through an Organic Extrusion Press (or OREX) which is the heart of the Facility. Having an operation similar to a lemon juicer, the OREX squeezes out the organics from the waste in the form of a pulp by applying extremely high pressure. The extracted pulp is then transferred to the bio-methanation chamber for generating biogas.
• The Biogas is scrubbed to remove hydrogen sulphide and moisture. Gas turbines then generate electricity from the clean biogas.
• The slurry from the bio-methanation chamber (after the biogas is extracted) is dewatered and sent to the in-vessel composting drums which convert it into compost that is sieved and bagged for further use.
• The Dry Fraction from the Orex is passed through a Screen and a Wind-Sifter for separating the RDF and the Grit. The RDF is sent to Cement Companies as a fuel and the grit is used for filling of low-lying areas or is disposed of in the sanitary landfill.
• The Effluent Treatment Plant present on site treats water from the Facility and recirculates it for uses such as gardening, floor cleaning, flushing, etc.
The beauty of the Facility lies in the fact that the Electricity generated from the wet waste is used to power the entire plant and the surplus power can also be fed to the grid.
The entire Facility operates in shifts like a Factory and the standards of cleanliness maintained are very high.
Walt Disney said, “All our dreams can come true if we just have the courage to pursue them”. The Calangute Solid Waste Management Facility is a dream which the Government of Goa saw and pursued. Now we all have to pay a visit to the site to witness how beautifully it has come true!
Photo credits: M/s Hindustan Waste Treatment Pvt. Ltd. & Solid Waste Management Cell, Dept. of S&T, Govt. of Goa