Using city roofs for climate improvement and water security
Cities have have limited room for the retention and infiltration of rain water. This leads to the need of a large capacity drainage system. The climate change results in more extreme precipitation, that will surpass the design capacity of existing drainage systems. The lack of retention and infiltration also leads to a dry climate in cities and a falling ground water level. As a result, more irrigation is needed for green zones within the city limits. City roofs offer a possibility for the retention of rain water, resulting in avoided costs for the adaptation of the drainage capacity, en a reduced need for imported water. A study has shown that the idea is feasible.
Measuring beer bitterness by fluorescence technique
Iso-alpha acids are released by the addition of hops in beer and cause a specific bitterness. Besides hops, also the addition of some dark malts result in a bitter taste. The concentration of iso-alpha acids can be measured by fluorescence excitation. This enables better control of the brewing process and a more precise analysis of beers.
Legionella detection in drinking water
The Legionella bacterium can grow in drinking water systems and present a hazard to specific target groups such as patients and the elderly. Lab tests are expensive and take several days to perform. Fluorescence techniques in combination with immobilized specific bacteriophages can be used to capture Lagionella bacteria. To detect these, a very high sensitivity detector was developed using digital signal processing techniques. The next step is the development of capture arrays that can be used in a continuous detection system.
High accuracy effluent measurement in brooks
Precise effluent measurment in brooks can produce valuable information for scientific biological research as well as management of natural waters. The system uses a stilling well and a sensitive difference pressure measuring cell, and a high dynamic range measurement system. The system is calibrated before every measurement period, to reach a 1% accuracy over a highly variable effluent.