Monitoring of rapid sand filters using an acoustic imaging technique

Monitoring of rapid sand filters using an acoustic imaging technique

Allouche, N.
Simons, D.G.
Rietveld, L.C.

Civil Engineering and Geosciences

Water Management

2012-11-04

A novel instrument is developed to acoustically image sand filters used for water treatment and monitor their performance. The instrument consists of an omnidirectional transmitter that generates a chirp with a frequency range between 10 and 110 kHz, and an array of hydrophones. The instrument was extensively tested in a lab before being deployed in an industrial rapid sand filter, made available by a Dutch drinking water company. This filter was monitored over a period of 10 days. We performed a scan every two hours. The obtained images are processed and compared. Clear changes in acoustic response were detected mainly at the top 20 cm of the filter bed. Two important observations can be made from the analysed data. First, the filter bed is compacting during filtration. This seems to be linearly increasing with the filter run time. The second effect is the relative acoustic “transparency” of the filter bed directly after backwashing. Small-scale accumulations of particles are detected. These observations show the great potential of this acoustic-based tool in monitoring the performance of a rapid sand filter.

acoustic waves
rapid sand filters
monitoring techniques

http://resolver.tudelft.nl/uuid:e987affa-2752-472b-b9d9-731ee603409f

IWC International Water Conference: New Developments in IT & Water, Amsterdam, The Netherlands, 4-6 Novovember 2012

Institutional Repository

conference paper

(c) 2012 Allouche, N.
Simons, D.G.
Rietveld, L.C.