Background The maintenance and supervision of cooling towers and air-conditioning systems cause significant environmental impact through excessive use of chlorine and other biocides. Users and managers of cooling towers and air-conditioning systems apply biocides to the circulating cooling water to control growth of microorganisms, biofilms and algae. The chemical products used are oxidants and harmful to human health and the environment. However they tend to be used in excess as a security measure to ensure prevention of microbial contamination that can lead to serious infections, such as legionnaire’s disease. Currently, monitoring systems calibrate biocide doses based on regular aerobic microorganism counts to prevent too high doses that could harm the workers and too low doses that could enable microbiological contamination of the installation. However, these must be carried out in a laboratory, using an analysis system that tests a filtered, cultivated sample from the installation. The results typically take between 24 and 48 hours to deliver. During this time, use of biocides tends to err on the side of too much to guarantee no microbiological contamination, leading to water contamination and air pollution. Objectives The principal aim of the 'BIOMOMI' project is to validate and demonstrate a new technology that allows the real-time monitoring and quantifying of aerobic microorganisms present in the water of a hydraulic system, and the subsequent correct dosage and constant optimisation of an adequate biocide to minimise contamination risks. The project plans to design and construct a prototype that can perform real-time monitoring of the concentration of aerobic microorganisms in water (control unit) and the concentration of biocides necessary for water treatment (dosing unit). It will develop software and programming for correct communication between the dosing unit and the control unit as well as for the collection of analytical data for monitoring. It will test the system at industrial-scale in two representative Spanish textile companies with very different hydraulic systems, both of which require disinfection: the cooling towers of a finishing company and the air-conditioning system of a weaving company. The project will identify critical points in each circuit for sample-taking and it will install, adjust and optimise the prototype. It will also study and optimise the synergetic effect of both oxidising and non-oxidising biocides and determine the compatibility, bio-efficiency and kinetic reaction between both types. A study will compare the technical and economical advantages of the technology demonstrated, with respect to traditional control systems. The results will then be disseminated to other industrial sectors where hydraulic systems are used and where microbiological monitoring and continuous biocide dosing is necessary. Expected results The successful demonstration of real-time analysis of aerobic microorganisms in water systems will allow intelligent dosing of oxidising and non-oxidising biocides in appropriate proportions at critical points in the installations. This will deliver: An analysis of aerobic microorganisms within hydraulic systems within 15 minutes; Considerable reduction in the use of chemicals, reducing or preventing the creation of potentially carcinogenic compounds, such as trichlorobenzene or trichloromethane; Concentrations of free chlorine in the water maintained within safety margins; Reduced contamination of air and water by excessive biocides; An expected reduction in maintenance costs of 10-20%; Increased lifetimes of hydraulic systems and equipment, reducing demand for raw materials and energy; and It will create the potential for more stringent regulatory controls on the use and discharge of biocides in hydraulic systems.