Measuring microbiological activity of aqueous solutions, used for monitoring drinking water quality, by measuring reduction in oxygen concentration over time

摘要

#CMT# #/CMT# The reduction in oxygen concentration of the aqueous solution over time is measured and correlated with one or more parameters indicating a microbiological activity. #CMT# : #/CMT# A method for measuring the microbiological activity of an aqueous solution comprises the following steps: (1) adding an aqueous solution to a vessel; (2) measuring the oxygen concentration of the solution as a function of time; (3) measuring the reduction in oxygen concentration over time (dO2/dt); and (4) correlating the measured reduction in oxygen concentration over time with one or more parameters indicating a microbiological activity. Independent claims are also included for the following: (A) Method for measuring and controlling a membrane filtration unit with inlet and outlet lines by removing an aqueous sample from the inlet line and measuring its microbiological activity using the above method; (B) Microbiological activity measuring device for carrying out the above method; and (C) Installation for purifying an aqueous flow using a membrane filtration unit and including the microbiological activity measuring device. #CMT#USE : #/CMT# For measuring the quality of drinking water produced by membrane filtration. #CMT#ADVANTAGE : #/CMT# The water purification process can be adapted more quickly and easily in response to changes in water quality due to microbiological contamination. #CMT#INSTRUMENTATION AND TESTING : #/CMT# PREFERRED METHOD : The microbiological parameters are chosen from AOC (Assimilable Organic Carbon), BOD5 (Biological Oxygen Demand after 5 days), ATP or colony count, or its combination. Step (2) is carried out under conditions which prevent oxygen exchange between the solution and the surroundings, at a constant temperature of 20-37[deg]C. After step (4) the solution is removed and the vessel is cleaned, rinsed with water and rinsed with the solution and steps (1)-(4) are optionally repeated. The results of step (2) are used to carry out a mathematical calculation using a regression model in step (3). Step (2) comprises the sub-steps of measuring the carbon dioxide concentration and pH of the solution as a function of time and lasts at least 24 hours. One or more nutrients are added to the vessel. PREFERRED DEVICE : A means for maintaining the solution at a given temperature and a means for providing a cleaning agent are included.