Water monitoring One of the key objectives of the TTT, in

combination with the improvements to the five sewage treatment works, will be to control discharges and improve river water quality.

Water quality monitoring Sampling for laboratory analysis provides an opportunity to analyse a wide variety of parameters including the priority substances identified by the EU Water Framework Directive. Continuous monitoring, however, fulfils a different purpose; providing a continuous data stream for key indicative parameters such as pH, conductivity, turbidity, dissolved oxygen, ammonium, Blue Green Algae and chlorophyll. This enables the detection of sudden changes that arise from pollution incidents; helping to raise timely alarms and identify the source of pollution. One of the most important benefits of an

integrated system that monitors an entire catchment is the ability to track pollution events as they move with the river, so that water treatment plants can adjust their intakes accordingly. In addition, by monitoring all day every day, Meteor’s scientists are able to accommodate the significant effects of tidal water with software known as ‘Half Tide Correction’ (HTC). Meteor’s HTC software creates zones in the

river which are defined by their distance from a fixed point, such as a bridge. This enables the continuous monitoring of water quality in each zone, wherever it is in the ebb and flow of the tide. As a result, water quality issues can be detected very quickly, which means that timely mitigation measures can be deployed – emergency water oxygenation for example. In the River Thames the worst water quality

issues typically occur when sudden high levels of rainfall follow a dry period. This is because waste materials accumulate and concentrate during dry periods and when stormwater rushes into the drainage system, the leading edge of the flow is generally the most polluted, and it is this issue that the TTT is targeted to address. Nevertheless, it is possible that CSOs will still discharge into the Thames after the Tunnel is opened (in 2025), but the Thames Tideway Tunnel Scheme will ensure that around 95 per cent of CSO discharges are diverted for treatment.

HigH intensity monitoring In the UK, the decline of manufacturing, coupled with investments and improvements in wastewater treatment systems have contributed to an overall improvement in Thames river water quality. However, storm overflows typically initiate sudden sags in dissolved oxygen - often in conjunction with a rise in ammonium. The speed with which such changes can occur necessitates (almost continuous) high intensity monitoring. Over the last 20 years Meteor

Communications has developed and refined its range of ESNET (Environmental Sensor NETwork) continuous water quality monitoring systems, so that they can be quickly and easily deployed at almost any location; delivering data via telemetry within minutes of installation. The systems are available in a kiosk for semi-


permanent installations or as a portable unit for temporary monitoring projects or investigations. Each system is built around a battery-powered multiparameter water quality sonde which takes readings at 15 minute intervals (although faster measurements are possible). Data are then transferred by 3G/4G to a central database. Modularity is a vitally important feature of

the ESNET systems. For example, the core components of a kiosk system are exactly the same as a portable system. This means that, for example, a kiosk system can be converted into a portable system within seconds, and sondes can be swapped without harming data accuracy or integrity. To support the 500+ ESNET monitoring

systems that are currently in operation on rivers and at treatment works across the UK, Meteor Communications has established a dedicated Water Quality Services Hub near Basingstoke. The company’s ‘Water Quality as a Service’ operation is handled by this facility. Under this scheme, customers do not own the monitors; they simply pay for access to their own water quality data. Meteor installs and operates the ESNET systems and the sondes are exchanged on a monthly basis, after which each sonde is returned to the Basingstoke laboratory where it is serviced and calibrated before redeployment.

summary Historically, many societies have treated rivers as drains; providing a vehicle for the removal of waste and flood water, but today the real environmental and amenity value of rivers is better appreciated, and the Thames Tideway Tunnel Scheme is a good example of the work that is being undertaken to improve the quality of UK rivers. Continuous monitoring performs a vital role in all such initiatives.

Over the last 20 years, a number of factors

have combined to enable the implementation of highly effective water quality monitoring. Sensor technology improvements have meant that readings do not drift and the periods between calibrations have been extended to enable long- term deployment. The latest communications technologies make it possible to gather data from almost anywhere, and to communicate with remote installations at low cost. Over the years, monitoring system hardware

has been improved so that it is compact, rugged, self-contained and modular. As a result, ESNET systems can be deployed quickly and easily; delivering data within minutes of deployment. There are many advantages to be gained from

monitoring networks as opposed to single monitors. For example, with larger numbers of sensors, it is possible to identify and reduce areas of data uncertainty. In the future, it may also be possible for algorithms to be created that reduce the requirement for manual calibration. Monitoring networks enable the tracking of

pollution and help to identify the sources of pollution. This information can be used to develop better informed interventions and to help farmers and other landowners adopt practices that improve water quality. With the benefit of the HTC module,

monitoring systems are able to assess the effectiveness of the measures contained within projects such as the Thames Tideway Scheme, so that the value of investments can be qualified; thereby informing decisions on future developments. Looking forward, it is inevitable that more high-intensity monitoring systems will be established as the world’s great conurbations develop into smart cities.

Meteor Communications

April 2021 Instrumentation Monthly

Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74