N Puri1, S Awasthi1, A Kesarwani2 and A Goyal1 #
1Isgec, A-4,Sector -24, Noida 201301, India
2CST, Greater Kailash II, New Delhi 110048, India
In India, sugar is often refined using the double-sulphitation method, as it is a cheaper process for sugarcane juice clarification than other available processes. However, the major drawback of this process is that sulphur enters the sugar during its clarification process. The end product that goes to the consumer contains sulphur dioxide at a concentration ranging from approximately 20 to 30 ppm. This limit is enforced, due to the impact of sulphur on human health. Due to various disadvantages including health, product value, market access, operational efficiency, environmental benefits, and brand recognition, the double sulphitation process has gradually been replaced with sulphur-less refining by many sugar plants in India. During the conversion process in 2023-2024, Saraswati Sugar Mill (SSM), besides installing the standard clarification and decolorization stages of phosphoflotation and ion exchange, added two significant steps that not only improved the sugar yield by reducing total sugar losses but also made the factory more energy efficient, greener and environment friendly. The two additions were: decanter-based mud removal systems (MRS) that replaced the existing rotary vacuum filter (RVF) and a zero liquid discharge (ZLD) system for the effluent generated during the ion exchange process. These additions are described, along with the impact on the sugar yield and the environment.