Medichem S.A. is a company dedicated to the development of processes and manufacturing of pharmaceutical active principles.

In one of its two productive centers, located in Celrà (Girona), they have two multipurpose plants in which the manufacture of the products in batch and for specific campaigns takes place.

The 70% of the waste generated in the manufacture pharmaceutical products are valuable solvents and the 20% are contaminated waters. These, due to their salt or solvent content cannot be processed in the municipal sewage treatment plant, for this reason the company has its own wastewater treatment plant.

The sector in which Medichem S.A. works, uses great quantities of raw material, consequently, a large amount of waste is generated. On average, about 12 kg of waste is generated per 1 kg of manufactured product, mainly hazardous waste. Therefore, the cost of waste treatment is significant in the final cost of the product.

Through the study of all the processes and applying a minimization scheme, Medichem S.A. achieved a significant reduction in the cost of waste treatment. This was possible because of the management of some waste as by-products. Below are pointed the 3 cases of waste generated in the production process of Medichem S.A. which are managed as by-products according to the Catalan regulatory framework:

• Non-halogenated organic solvent: the distilled solvent in the process is a residual product containing 90% organic solvent and 10% water. Medichem S.A. contacted a company dedicated to the manufacture of rectified alcohols, where the non-halogenated organic solvent could replace the raw material for the manufacture of these alcohols.
• Ammoniacal waters: in the process of regeneration with ammonia of ion exchange columns, for the manufacture of an antiepileptic agent, amonuclear waters are generated. However, the internal purifier is not able to treat this kind of waste. For this reason, Medichem S.A. contacted a company interested in nitrogen waters for the manufacture of fertilizers and nitrogen fertilizers. Thus, the by-product totally replaced the necessary water and partially the nitrogen.
• Aqueous solution of ammonium sulphate: the residue of the aqueous solution of 40% ammonium sulphate comes from a decantation in which ammonia is used to neutralize sulphuric acid in the manufacture of an active pharmaceutical product. Due to the content of the solution the internal purifier is not able to treat them, for this reason this solution is transferred to another company as a by-product, substituting raw material in the process of manufacturing chemicals.

The management of waste as a by-product provided the following advantages:

• Important cost savings for waste treatment.
• Minimization in the use of raw material purchased.
• Reduction in the management of administrative procedures.