Appraisals (engineering services), namely design of water treatment, purification and conditioning installations and procedures, scientific and technical research, experimentation and industrial application of purifying and conditioning treatments for liquid and gaseous fluids, scientific and technical studies carried out by engineers concerning the treatment and conditioning of water by means of physico-chemical or biological procedures and products; scientific and technical studies carried out by engineers concerning the use of water treatment installations; technical auditing (engineering services), technical studies carried out in laboratories, namely technical research, engineering services and consulting with regard to all forms of fluid treatment, particularly in the field of sea water desalination