Before the adaptation of the microorganisms, a series of processes to adapt the laboratory media to the work procedures in bioleaching were carried out:

- The development of a safety and health protocol has been developed

- Sterilization techniques for the media have been studied

- Study of the microorganisms that could be present in the reaction conditions that can compete with the Acidithiobacillus ferroxidans.

- Non-metallic part of PCB pre-treated with saturated NaCl and further washed

- Test equipment performance during scaling up (250 ml - 1 L - 10 L - 50 L)

Non-metallic part of PCB pre-treated with saturated NaCl and further washed

Adaptation and scaling up process of Acidithiobacillus ferroxidans with the non-metallic fraction obtained after mechanical treatment of PCBs:

The process consists in 6 steps:

- Step 1: Vials inoculation

- Step 2: Adaptation to 250 ml

- Step 3: Adaptation to PCB in 250 ml

- Step 4: Adaptation to PCB in 1 L

- Step 5: Adaptation to PCB in 10 L

- Step 6: Adaptation to PCB in 50 L

Steps 1-3 from adaptation and scaling up process.

Steps 4-6 from adaptation and scaling up process.

The development of a 50 L prototype for bioleaching operations of the non-metallic fraction of PCBs after mechanical treatment by the microorganisms Acidithiobacillus ferroxidans was carried out.

50 L prototype built for BIOTAWEE Project.

The prototype consists on the following equipment to control the operating conditions during bioleaching:

- pH analyzer that will facilitate both the supervision of the evolution of the pH of the reaction and also the possibility to the pH at a constant value.

- Stirring controller + aerated rod for controlled agitation that does not hinder the evolution of microorganisms and also incorporates aeration in the rod to improve air recirculation for the benefit of the aerobic reactions that take place.

- T controller that allows us a precise control which is of great importance for the reactions and survival of microorganisms.

The design of the required technology to reproduce the process has been carried out, increasing the scale to a capacity of 50L. Providers have been contacted and the revision of bids is nearly completed.

Design of the required technology for the 50 L reactor.

In the meantime, the revision of the laboratory material needed for the test has been performed. Before starting the test on a 50L reactor, the consortium has to be previously adapted to the PCB in flasks of 250ml, increasing the volume progressively, being the previous volume to the 50L-reactor a 10L-reactor already owned by INATEC. This reactor, equipped with sensors and agitation, has been checked and the reagents and material required for working with microorganisms have been listed.

Test performed in the 10 L reactor in order to check the performance.

Processing PCBs includes several steps of crushing and separation until a non-metallic fraction to test by bioleaching technology is obtained. Next figure shows the three steps of the global process where the material has to pass until the final fraction is achieved:

Material through each step of the process.

1^st STEP: The process begins with the crushing of the material in a shredder.

2^nd STEP: The material is introduced in the mill during continuous cycles.

3^rd STEP: The aim of this step is to separate the metallic fraction from the non-metallic one.

MATERIAL FOR BIOLEACHING: The non-metallic fraction obtained in the previous step is the one selected to be used in the bioleaching process that will be carried out by BIOTAWEE consortium.