A pre-treatment process can turn ordinary retail waste into high value micro-algae feed

Food waste among retailers is often fought through a number of usual alternative valorisation approaches such as last hour mark-downs, food banks donations, internal consumption, etc.

Although these are good practices and well known for having successful impacts both economically, environmentally and socially speaking, they are never enough to deal with the full amount of surplus food that a market with high availability and wide variety of products generates.

This is why over 10% of the global food waste is generated in retail*, resulting in over 100 million tonnes of food which did not make it to anyone’s home.

Such numbers call for new and ambitious alternatives to the already existing ones.

In store pre-treatment

The novelty we propose in this Living Lab aims to implement a pre-treatment process, in-store, for the retail food waste in order to transform it into a dehydrated “powder” that can be used for microalgae feed.

Simply put, all that is needed is a drying machine that, thanks to automatic temperature and humidity control, dries and crushes the waste until just a powder with less than 80% of the initial volume.

Then, this powder needs to be valorised. When using this type of food waste in a circular economy approach, it is preferable to link the solutions with high value-added applications that can cover the corresponding costs and ensure the economic feasibility of the valorisation process.

*United Nations Environment Programme (2021) Food Waste Index Report 2021.

Microalgae are multi-purpose helpers of the future

Using this powder as a culture medium replacement or supplement for microalgae production appears to have interesting potential as this represents 20% of microalgae’s total production cost. 

Selected cultivated species can then be used for biopolymers and cosmetic production. From the many microalgae species available, we will select which ones to work with towards the end of 2022. 

Finally, to make this work, the right logistics infrastructure needs to be settled so that the output of our in-store process can move from retail to microalgae producers in a cost-efficient way. 

Proof of concept on the way

With Sonae ensuring the retail waste and pre-treatment process, University of Minho guaranteeing all the necessary tests and validations to the formula produced, and Allmicroalgae dealing with the algae cultivation experiments, we expect to have a cohesive demonstrable process plan by mid-2023.

Objectives 

• To develop an optimal and feasible solution for in-store and in-warehouse FLW pre-treatment (especially fruits, vegetables and animal proteins), addressing waste from stores (and equivalent premises).
• To characterise the pre-treated FLW and valorise it into the production of micro-algae.
• To develop a reverse logistics process that takes into account safety regulations, business constraints, the complexity of FLW being decentralized in the retail context, and the use of innovative hermetic containers for transportation.