Sampling in the driving seat

Encouraging the water industry to take control of its own sampling

Is it the mistaken belief of some companies that the introduction of a wastewater sampling regime will require a considerable amount of labour and record keeping? According to sampler manufacturer Aquamatic, the option of taking samples every day, possibly on the hour, does not mean they always have to be analysed. Moreover, there is now labour-saving equipment available to ensure samples of a previous day's effluent can be easily provided.

Peter Smith, Aquamatic's managing director, explained: "Some businesses seem to be under the impression that because samples are being collected there is then an additional burden and cost of analysis - but this just is not the case. If required, either when visited by the local water company or when looking at a production issue, a self-emptying polypropylene bottler (SEPB) can automatically collect daily composite samples. The beauty of an SEPB is that it always has the previous day's composite sample available - without any hassle." An SEPB can be programmed to intelligently empty one of the unit's two 4.5-litre containers each morning, prior to the start of the day's sample routine, while the other container retains the previous day's composite sample.

The potential for blockages is averted by the sample containers' capability to tip out their own contents, and because this is accomplished with a highly vigorous scouring action, the minimal residue virtually eliminates the risk of cross contamination. When an industrial firm selects a wastewater sampler, one consideration might be the choice between a unit with a peristaltic pump or a sampler with a vacuum-powered air pump.

On paper, the peristaltic pump may appear cheaper, but Smith says important maintenance issues must be considered. "Both types of samplers can perform the task in hand", he said, "but with peristaltic pumps, there is an ongoing need to replace worn out tubes.

"This is not that costly in terms of the actual part but it is an unnecessary nuisance compared to an Aquamatic sampler, designed with a vacuum-powered air pump, which does not require frequent changing of parts." Aquamatic was the first wastewater sampler manufacturer to have one of its portable samplers successfully complete the WRc's rigorous test programme. The Aquacell P2 Coolbox achieved compliance with E32 specification (the Environment Agency's E32 technical report is the UK's interpretation of the Urban Wastewater Treatment Directive as it is applied to automatic sampling equipment).

"E32 compliance is still the main driver at the moment", added Smith, "and this is not just coming from the water companies. An E32 compliant sampler can be confidently used in virtually any application - municipal or industrial."

industrial trends

Smith continued: "We are also seeing a trend with industrial users that when they begin to do their own sampling, it often develops into an opportunity for them to examine the overall performance of their plant, helping them understand the reasons why their effluent is the way it is. They sometimes discover they are inadvertently sending valuable product straight down the drain.

"By using samplers they can identify problem processes such as incorrect tank flushing, which might be contributing to the costly effluent charges they are experiencing. The variation in effluent at different times of day can sometimes be as obvious as the sample being a totally different colour. It might be expedient for a company to take samples every hour, rather than just once every 24h in order to pinpoint where savings could be made."

As far as the water companies are concerned, there are still a great many medium-sized and particularly smaller treatment works still requiring samplers by the January 1, 2006 deadline for the Urban Wastewater Treatment Directive. Demand for portable equipment could increase significantly, especially for remote WwTWs where, depending on the population the plant is serving, samples may not be needed that frequently.

Portable equipment, not relying on external power, and designed for keeping collected samples at 0-50°C for up to five days, is likely to be popular. However, it probably will not be looked on too favourably by the authorities unless it is E32 compliant. For the multiple sampler user there is the advantage of distributing samplers at different locations before the sample is required and then collecting them later when the sample has been taken - safe in the knowledge storage of the sample will be at the right temperature.

"Sampling now plays a vital role", concluded Smith, "the water companies know they have to keep their own house in order and an increasing number of industrial users, often helped and advised by the water companies, are realising they can put themselves in the driving seat by doing their own sampling. Factories pay less for their effluent discharge, water companies have less pollution to deal with and the environment wins too."



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