CSIR lab’s innovative way to treat sugar waste
The 300-odd molasses-based distilleries in India are churning out 2.5-2.6 billion litres of alcohol annually. They also discharge 30-35 billion litres of molasses, which, if disposed untreated, can contaminate surface and ground water.
The Central Salt & Marine Chemicals Research Institute (CSMCRI), Gujarat, has developed a process to separate the main source of pollution — potash and biodegradable organic matter — from distillery spent-wash. It is claimed that this technology will not only help distilleries comply with the Central Pollution Control Board’s mandated zero liquid discharge (ZLD) action plans, but also meet up to a tenth of India’s potassium-based fertiliser requirements, now entirely met through imports, reports Indian Express.
The technology separates complex organic compounds from spentwash through a coagulation process. The subsequent processes involve recovery of potash salts from the “lean” spent-wash, which then undergo evaporation to yield recycled water and residues. The residues are further mixed with the organics recovered in the first stage. This generates valuable organic matter, potassium nitrate (fertiliser) and reclaimed water (reusable in the molasses fermentation process).