Electrical Resistance Tomography for sewage flow measurements

Abstract

Sewage network management is critical to efficiently collecting and transporting wastewater; thus requires proper monitoring schemes. Electrical resistance tomography (ERT) has been reported in many industrial applications due to its high temporal, low cost, non-invasive, and non-radiation emitting features. In this thesis, an ERT system is developed for monitoring sewage flow to allow for further system automation and control. A bespoke ERT data acquisition device, which cost much less than the current commercially available ERT devices, was firstly developed and tested in the lab-scale experiments,. The performance of the ERT device was demonstrated in both the static and dynamical scenarios, proving its capability in capturing flow behaviours. Particularly, the functional ERT method was exploited to extract dynamic information by combining time-series of ERT measurements. Such method allows for the visualization of flow dynamics as well as the estimate of flow velocities. In addition, the system was also evolved for operating in horizontal partially filled pipes, where free flowing sewage happens. The major problem related to the partially full flow is that some electrodes lose contact with the fluid and hence results in erronueous measurements. This problem raises the following two challenges: 1) we need to recognize and eliminate the erronueous data points; 2) we need to reconstruct images with the resultant incompete datasets. The former criteria was met by modifying the ERT data acquisition hardware in the way that it can detect the non-contact electrodes. A localized ERT imaging method was proposed originally to improve the spatial resolution for frequency difference ERT problems so that ERT could be adopted as a guiding tool in lung tumour tracking applications. This localized image algorithm was then applied to the deal with the incomplete datasets to enhance the image reconstruction and robustness of the ERT system; hence tackles the second challenge involved in the part full flows. This ERT wastewater metering development aims to achieve as cost effective as the traditional flowmeters but can provide visualized monitoring which can be interpreted into flowrate, gas/liquid/solid distribution, and conductivity.

Date of Award	18 Nov 2020
Original language	English
Awarding Institution	University of Bath
Supervisor	Manuchehr Soleimani (Supervisor) & Philippe Blondel (Supervisor)