Techno-economic viability of innovative membrane systems in water and mass recovery from dairy wastewater

Abstract

Viability of innovative treatment systems in recovery of water and mass from dairy wastewater was techno-economically investigated. Lab-scale experiments were carried out for water recovery from whey wastewater using two combined membrane processes as forward osmosis (FO)/membrane distillation (MD) and MD/reverse osmosis (RO). Raw whey was concentrated to the solid contents of 21.0% and 25.8% by FO/MD and MD/RO, respectively. Production of commercial whey powders was successfully accomplished by spray drying of the concentrated whey streams. Full-scale costs of both systems were individually estimated using process modeling and cost estimation software. The simulations for a design influent of 100m3/day showed that water can be recovered in sufficient quality to be reused in cheese production and the recovered amount increases up to 66–68% compared to 30% for that of UF/RO system. Besides, both treatment systems yielded a return of 12–13 million $ with annual net profit of about 800,000 $ as competing with UF/RO. Pay-back times of the system investments were determined as satisfactory as under 1 year due to annual revenues of about 3.4 million $ from water recovery and whey powder selling. The innovative systems studied seemed to have conclusively enabled more sustainable dairy waste management with good economic benefits.