Rajeev Nath Tiwari - Centre for Nanoscience & Nanotechnology, Panjab University, Chandigarh, India.Spray Engineering Devices Limited, Mohali, Panjab, India
Vivek Verma - Spray Engineering Devices Limited, Mohali, Panjab, India
Gaurav Verma - Chemical Engineering Department, Panjab University, Chandigarh, India
Suresh Kumar - Department of Applied Sciences, Panjab University, Chandigarh, India
Keya Dharamvir - Department of Physics, Panjab University, Chandigarh, India

Spentwash generated from the sugar cane molasses based distilleries; one of the most polluting industries generating large volumes of high strength wastewater [۱] is evaporated in the combination of multiple effect evaporators (MEE) and forced recirculation evaporator for effective concentration utilizing external heat energy for steam generation at high temperature. Due to high temperature evaporation in multiple stage evaporation system; scaling tendency dominated resulting in clogging of pipes, low heat transfer rate, loss of process and damage to the equipment such as heat exchangers, centrifuges, pumps, sensors and valves etc. [۲,۳]. The evaporation and concentration of spentwash at high temperature causes many problem like very high degree of scale formation, inefficient evaporation and concentration process, high pollution in condensate and environment, inefficient heat transfer coefficient, process energy loss, lot of problem to handle and disposal of spentwash [۴]. The arrangement and apparatus for spentwash evaporation and concentration in current scenario have many disadvantages like need of boiler and turbines for steam generation, need of cooling tower and condenser for heat rejection and other fuel/biomass requirement for firing into the boiler for steam generation, higher energy consumption, fast scaling of evaporation on heating surface due to high temperature operation, higher intake water from earth, higher footprint area requirement and higher operating and maintenance cost [۴]. The generated large volumes of high strength wastewater during spentwash evaporation systems are serious environmental concern and it have extremely very high chemical oxygen demand (COD) (۸۰,۰۰۰–۱۰۰,۰۰۰ mg/l), biochemical oxygen demand (BOD) (۴۰,۰۰۰–۵۰,۰۰۰ mg/l), total dissolved solids (TDS) (۲۰,۰۰۰-۱۲۰,۰۰۰ mg/l) apart from low pH, strong odour and dark brown colour [۵,۶]. The present paper is focused on the design and development of the equipment for operation at low temperature under the vacuum for maximum clean water recovery with minimum TDS, COD, BOD during spentwash evaporation along with reduced scale formation. Modified steel surface with nanomaterials plays a significant role in scale minimization along with high heat transfer rate.