NEW EU STANDARD WILL HELP BUILDERS' MERCHANTS JUDGE QUALITY
OF SMALL WASTE WATER TREATMENT SYSTEMS

By Alison Anderson, process manager for leading sewage solutions provider Klargester, and member of the team which developed the new standard.

Small wastewater treatment systems have been rapidly replacing septic tanks since the introduction of the H2 Building Regulations in 2002.

These regulations put building control officers in charge of soak-away design and generated an increased demand for environmentally friendly solutions.

Unlike septic tanks, which merely remove solids from sewage and discharge large amounts of pollutant, wastewater treatment systems break down the sewage and discharge effluent of a very high quality.

Small wastewater treatment systems achieve these results in different ways and use a wide variety of biological processes. However, until recently there have been no clear performance guidelines in place for these products and so it has been very difficult for purchasers to compare them.

It has also been difficult for manufacturers to trade across Europe, since they have been required to test their products to different standards for different countries.

However, this is all changing with the introduction of a new European standard - EN12566 Part 3: Small Wastewater Treatment Systems - which covers up to 50 population equivalents Package and/or Site Assembled Domestic Wastewater Treatment plants, and will bring much-needed conformity to the industry.

Firstly, the standard defines minimum product requirements. These include the fact that the equipment must be watertight and corrosion resistant, and fitted with an alarm to indicate operational failure. It must also be designed to allow easy access for routine maintenance, sampling and sludge removal.

The new standard also details a 38-week performance test, which will see key performance indicators of each product clearly stated on the CE (Communauté Européenne) marking label, which allows approved manufacturers to trade across the European Union.

All plants must be assessed against the following core parameters - total chemical oxygen demand (COD), biochemical oxygen demand (BOD), suspended solids (SS), power consumption, daily hydraulic flow and temperature.

Treatment efficiency ratios for BOD and SS are mandatory. However, other treatment efficiencies may also be declared to provide added reassurance for purchasers. These may include levels of ammonia, phosphate, sludge production, pH etc.

Performance tests are being undertaken in approved laboratories in Germany and Belgium by independent researchers. The tests are mostly conducted under "normal" (i.e. nominal flow) usage conditions, which include defined intermittent flows during a 24-hour period. The performance of the product in the event of a problem, such as a power failure, underloading, or overloading, is also assessed.

Following the successful completion of the tests, the product's key statistics, including its daily hydraulic load, treatment efficiency and electrical consumption, will be clearly recorded in documentation. Other tested performance indicators, such as the nitrogen parameters and total phosphorus, may also be included. In addition, the manufacturer's name and address will also be clearly identified, and a label indicating the product's test status may be supplied.

Other significant information highlighted in the test report includes how much maintenance was required during the testing, how easy it was to access the components and how much power was required to operate the unit.

The standard has been prepared by the Technical Committee CEN/TC 165 "Wastewater Engineering" under a mandate provided by the European Commission and the European Free Trade Association, and supports key EU directives.

Klargester completed the testing in June 2005, with its BioDisc sewage treatment plant passing with flying colours. The company believes that it is the first manufacturer in the UK to complete the performance testing successfully.

Manufacturers who do not test their products to the standard will not be able to export them for use in other European Union countries, unless they can prove to regulators by some other means that their goods will perform and are of a sufficiently high quality. It is understood that the UK environmental regulators will recommend the installation of CE marked products.

Manufacturers now have a transition period in which to carry out the performance and other specified tests enabling them to ensure that their products comply with the standards requirements. The normal 12-month transition period has been extended to allow for the lengthy testing and expires in July 2008.

By testing products to the same rigorous standards, we will bring real conformity to the industry, making it easier for builders' merchants and other purchasers to judge the quality and effectiveness of individual products for themselves. This can only increase consumer confidence and understanding, and help to ensure a safer environment for everyone.

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