Minimal Liquid Discharge system for sustainable dairy wastewater management

Minimal Liquid Discharge system for sustainable dairy wastewater management

WoS Article

The dairy industry is a significant producer of wastewater, contributing to the deterioration of both the quality and quantity of freshwater resources. Moreover, the high daily and seasonal variability in the composition and volume of dairy wastewater poses challenges for efficient recycling. Minimal Liquid Discharge (MLD) systems, capable of achieving water recovery rates of up to 95%, have attracted increasing attention from both scientific and industrial sectors. However, their technological complexity, high energy requirements, and the challenge of managing produced concentrate remain significant barriers to broader industrial adoption. In this study, an MLD system comprising microfiltration, reverse osmosis, and an agitated vacuum evaporator was designed and experimentally evaluated. Additionally, the biogas yield potential of the produced sludge was assessed to explore sustainable concentrate management strategies. At a water recovery rate of 89.8%, the treated effluent exhibited COD, BOD, and TDS values of 66 mg/L, 55 mg/L, and 134 mg/L, respectively, indicating strong potential for reuse as rinsing and cleaning water for non-food surfaces or as cooling water. A biogas yield of 32.3 Nm3/tFM demonstrates that the sludge could be a viable co-substrate for anaerobic digestion in biogas plants. Furthermore, the techno-economic assessment revealed that, for optimized water recovery rates, the payback period can be as short as 2.8 years, underscoring the economic viability of this approach. Future development will focus on system optimization, long-term operation tests to better understand the system behavior, and economic sensitivity analysis to investigate the impact of various factors.

The dairy industry is a significant producer of wastewater, contributing to the deterioration of both the quality and quantity of freshwater resources. Moreover, the high daily and seasonal variability in the composition and volume of dairy wastewater poses challenges for efficient recycling. Minimal Liquid Discharge (MLD) systems, capable of achieving water recovery rates of up to 95%, have attracted increasing attention from both scientific and industrial sectors. However, their technological complexity, high energy requirements, and the challenge of managing produced concentrate remain significant barriers to broader industrial adoption. In this study, an MLD system comprising microfiltration, reverse osmosis, and an agitated vacuum evaporator was designed and experimentally evaluated. Additionally, the biogas yield potential of the produced sludge was assessed to explore sustainable concentrate management strategies. At a water recovery rate of 89.8%, the treated effluent exhibited COD, BOD, and TDS values of 66 mg/L, 55 mg/L, and 134 mg/L, respectively, indicating strong potential for reuse as rinsing and cleaning water for non-food surfaces or as cooling water. A biogas yield of 32.3 Nm3/tFM demonstrates that the sludge could be a viable co-substrate for anaerobic digestion in biogas plants. Furthermore, the techno-economic assessment revealed that, for optimized water recovery rates, the payback period can be as short as 2.8 years, underscoring the economic viability of this approach. Future development will focus on system optimization, long-term operation tests to better understand the system behavior, and economic sensitivity analysis to investigate the impact of various factors.

Reverse osmosis, Microfiltration, Vacuum evaporation, Biogas, Recycling, Concentrate valorization

Reverse osmosis, Microfiltration, Vacuum evaporation, Biogas, Recycling, Concentrate valorization

HORŇÁK, D.; PROCHÁZKOVÁ, M.; MIKLAS, V.; VONDRA, M.; TOUŠ, M.; KOLLMANN, M.; JIA, X.; ŘÍHOVÁ, M.; PIŠANOVÁ, M.; MÁŠA, V.

18.11.2025

SEPARATION AND PURIFICATION TECHNOLOGY

373

18 November 2025

Kingdom of the Netherlands

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18

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https://doi.org/10.1016/j.seppur.2025.133556