Severn Trent invest in the Portable Oxyguard

Severn Trent has invested in the Partech Instruments new range of portable dissolved oxygen monitors for duties in its East Midlands Sewage Treatment Region, to check existing installed probes

The Partech Handy range of monitors comprise a probe and display meter, and produce highly accurate and repeatable results.

Severn Trent is now using 40 portable Handy units to manually check the dissolved oxygen in its activated sludge plants within the region.

Whilst the company has fixed probes on the sites that measure the DO and control the blower or aerator accordingly, Severn Trent needs to be able to check that these probes are working correctly, which where the Partech units come in.

"Maintaining the correct levels of DO in the aeration lanes is essential to ensure that we achieve our final effluent consent as determined by the Environment Agency," comments Lisa Lawton of Severn Trent.

"It is the fixed probes that mostly achieve this but it is also important that these are checked on a regular basis.

Were any problems with the probes to go unnoticed, as well as causing problems in respect of effluent compliance it could also cause us to over-aerate the sewage, which is a waste of electricity and money," continues Lisa Lawton.

Partech offers four models.

Alpha provides measurement in mg/l (ppm) or %SAT.

Beta provides measurement in mg/l (ppm) or %SAT and temperature, with an illuminated display meter.

Gamma provides measurement in mg/l (ppm) or %SAT and temperature, plus manual compensation for salinity.

Delta provides measurement in mg/l (ppm) or %SAT, temperature and barometric pressure, plus manual salinity compensation.

This model also comes with a built in data logger with the ability to record up to 52 measurements.

Severn Trent has opted for the Delta model because the data-logging feature allows operators to see what is happening to the oxygen levels in the ASP overnight.

Operators can set the unit to log at regular intervals, with the data then being trended to see if any particular patterns emerge.

The first Oxyguard was supplied by Partech to Severn Trent's processes section, to be used for carrying out works surveys.

Having noted how well it performed and how easy it was to operate, it was recommended to operations personnel for trials.

Operated by pushbuttons located on the cylindrical meter, the units are temperature compensated and easy to use.

The galvanic-type probe does not require a warm up period and can be stored dry without any detrimental effect on its accuracy.

The tough membrane can be wipe-cleaned either with cloth or paper and does not require regular service or replenishment.

Suitable for operation in all weather conditions, each of the models is completely waterproof and will float if accidentally dropped in water.

More than 1000 hours operation can be attained from the 9V battery.

"Reports indicate that our operatives find the Partech Handy easy to use," comments Lisa Lawton.

"Furthermore, it offers the benefits of being robust, weatherproof, whilst the data logging facility is very useful.

"Although currently being used in one particular region, we are sharing details with our colleagues in the West Midlands.

The portable Oxyguard is one of the tools that we use for ensuring our processes are operating within defined parameters and that we deliver an excellent final effluent quality as efficiently as possible.".

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