“Eggshells are a serious matter,” says Enrico Imperi of LABOR in Italy – one of the partners behind the SHELLBRANE project. In the EU alone, eggshell waste is expected to amount to 999 000 tonnes in 2015. Eggshells are considered hazardous waste under EU legislation and companies pay a lot of money dispose of them in landfill sites.

But landfills are not a sustainable option and landowners do not necessarily welcome waste of this type – the eggshell fragments still contain traces of egg white and the eggshell membrane. These, in turn, may contain bacteria that can attract unwelcome visitors such as rats.

From by-product to profit

The collagen and hyaluronic acid contained in the membranes can be used in cosmetic creams, medicines and food supplements. Manufacturers currently import the membranes but they are rarely pure, containing mineral shell fragments, bits of feather and microscopic dirt.

The project partners visited various industry events and found a clear demand for a higher quality product than is currently available.

Before the SHELLBRANE stage, egg processing companies have already broken the eggs, removed the egg yolk and white and crushed the shell into pieces of around 1cm².

Extracting the membrane

Once the pieces arrive, the SHELLBRANE team uses “a turbulent flow to detach the membrane from the mineral shell”, explains Albert Monferrer of project partner BDN in Spain. The turbulent flow in itself is nothing new, but SHELLBRANE has identified how to use this to break the shells into fragments of the right size – the right size being that which allows separation of the shell from the membrane.

As the shell and the membrane differ in weight, a combination of cyclone and decanter can then be used to separate both materials. The membrane is then dried using cold air.

Keeping it clean

The SHELLBRANE membrane extraction concept would not work without a disinfection phase. “When you break the egg, dirt from the outside comes in contact with it,” explains Imperi. To kill any bacteria without harming the precious membrane, the SHELLBRANE team uses ultraviolet rays. The rays penetrate any bacteria in the membrane, altering their DNA, so that they can no longer reproduce. This method ensures the membrane’s properties are preserved.

A prototype is already in operation in Hungary and is able to process 100 kg of eggshell per hour. “We have proved the concept, the next step is to improve the machine and its capacity. We would also like to make it more automated,” explains project coordinator Melinda Kozák of Ateknea Solutions in Hungary.

SHELLBRANE ended in April 2014 but the research is  ongoing. The partners hope to be ready to take the technology to the market in three to four years.

Below the SHELLBRANE eggshell membrane drying-disinfection unit

© Melinda Kozák