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

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 100 m3/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.