This work presents a proposal for the recovery of water through the treatment of food industry wastewater using membrane processes. Three wastewater streams from the different manufacturing steps were identified as possible sources of water recovery: (1) wastewater from the washing of ionic exchange resins and (2) wastewater from the concentration stage of animal proteins (type 1 and 2). The wastewater streams were treated as effluent mixtures; each one with different level of pollution. The principal characteristics of the effluent mixtures were identified as high conductivity and the presence of organic matter. Under these conditions, ultrafiltration and reverse osmosis were carried out for the treatment of wastewater. The ultrafiltration process was tested at an industrial-level plant and the reverse osmosis process was applied at a pilot-plant level. The results showed the feasibility of the proposed treatment for water recovery. The data demonstrates an efficiency greater than 95% in all the quality parameters and therefore, a high quality in the recovered water was obtained by membrane processes. According to the chemical composition of wastewater, the reversible fouling was linked to salts and protein retention, promoting the formation of a cake layer as reversible resistance; whereas, irreversible fouling was minimum during wastewater treatment.

Waste fractions of food processing are promising sources of polyphenols, which are of high demand because of their favourable bioactivities. More recently, also wastewater and process water fractions are in focus of research and technologies for downstream processing, which is reviewed here. Adsorption as well as membrane technologies are widely used to achieve selective recovery of polyphenols from waste water. For technical implementation the processing of waste fractions must be separated from the primary food production process. Therefore, the key step is the efficient transfer of the waste fractions into a storable and transportable form of polyphenol-enriched fractions. This strategy is shown exemplarily for the marzipan production. Almond skin and blanch water are waste fractions containing catechin and procyanidins, for which a recycling concept has been developed. The polyphenolic ingredients of the blanch water can be specifically adsorbed by means of Amberlite resins or zeolites with high yield followed by ultrafiltration.