Applications: Mobile data loggers applied in the sewer system

TELETRONIC Denmark ApS has designed a mobile data logger system to be used in a sewer system. Up to sixty outdoor stations are installed in sewer wells, pumping stations, combined sewerage owerflow locations and rainmeter stations - to collect data to the central main data logger. The central main data logger is connected to a computer.

All data transmissions are carried out using VHF/UHF radiofrequencies or the GSM mobile system. The TELELOG 2K2 DATALOGGER design is based on field experiences from systems installed in cities, open fields, in forrests, in lakes, in rivers, and at landfill sites. The design is continuously updated using the newest technology. The first system was delivered in 1993 and consisted of a central main datalogger and 10 outdoor stations. Today's systems collect data with a data capture close to 100 percent and the data loggers are often installed in wet and dirty surroundings. All dataloggers are supplied from a 12 Volt battery.

	Left: The drawing shows an installation of a TELELOG datalogger in a sewer well in a combined sewerage overflow. Just under the top of the sewer well a fixture carries a 12 Volt car battery, the datalogger, and the ultrasonic waterlevel sensor and a high level sensor. Right: The red ultrasonic sensor is installed in the top of the sewer channel and the high level sensor at the overflow barrier.
All equipment is totally hidden under the sewer top
	Left: In the middle of a busy road a TELELOG radio logger is installed. A flow meter or a water-level sensor is installed down in the sewer channel. Right: All the equipment is placed on a fixture adapted to the shape of the well top. A 12 Volt car battery and the radio logger is attached to the fixture.
Mobile data logger system in central Copenhagen
The picture below shows a PC monitor layout for a radio logger system in Copenhagen. It consists of 1 TELELOG MAINSTATION, 3 Rain meter stations, and 10 TELELOG radio loggers installed in combined sewerage overflow under busy roads around in the town. The data collected from the system is used to callibrate a computer based model of the hydraulics in the sewer system under different rain conditions. The green icons are radio loggers in the sewer system, and the blue icons are rain meter stations, that also act as radio repeaters for the installations in the wells. By setting the cursor to one of the icons, actual data is displayed on the PC monitor.
Illustration of data from the sewer system
Rainmeter station
The rain meter is installed in a hedge and is normally hidden except for the rain meter unit. It is powered from a 12 Volt battery charged from the main street light supply during the night. The print-out below, right, shows three accumulated rainfalls. It is a good illustration of a rainfall. It starts at the first rain drop and ends 1 hour after the last rain drop.
Combined sewerage overflow under a street
Print-out below: Shows three overflows simultaneously with the three rainfalls. The high water level sensor has been activated 3 times in a total of 26 hour and 31 minutes, changing the datalogger from normal to fast logging. Printout below, down: Shows another well in the same sewer system, where there has been no overflow.