Environmental and process assessment of a vibratory nanofiltration system for the recovery of water from soluble coffee manufacturing waste

A case study has been conducted for the recovery of water from complex wastewater at a soluble coffee manufacturing factory. The study has evaluated separation methods for process intervention based on environmental and economic assessments. A novel vibratory field membrane separation was evaluated at the laboratory scale using actual factory wastewater, and was scaled-up using appropriate design protocols. The recovery of water from an intermediate waste stream proved the most effective, both environmentally and economically. The proposed full-scale vibratory membrane process recovers 378,541 L of water per day that meets specifications for reuse in the factory cooling tower. The proposed design reduced the daily well freshwater withdrawn by 21% and the amount of wastewater discharged from the factory by 28.5%. Annual operating costs were reduced by 22.5% and total life cycle emissions were reduced by 27.8%. These reductions are mainly the result of the reduced volume of wastewater discharged from the factory and the reduced energy requirement of the on-site pretreatment processes. Economic assessment showed a net present value after 10 years is $181,100, while the payback time is under 3 years. Overall, the proposed vibratory membrane process used for water recovery presents favorable economics, and significant environmental emission reduction.