New dioxins monitoring system generates better emissions data
Formed in 1983 and based in Milton Keynes, England, Quantitech is a leading European provider of environmental testing and monitoring instrumentation.
The company recently welcomed delegates from industry, the UK Environment Agency, local authorities, the legal profession, environmental consultancies and the press to a seminar that considered the way ahead for dioxins monitoring.
Company director Dominic Duggan said: “The purpose of the day is to provide an overview of current dioxins monitoring procedures and to introduce a new system that has been developed by market-leading company TCR Tecora, which is based in Italy.”
Peter Middleton, business adviser for Scientifics, presented an overview of the situation relating to dioxins and furans. He emphasised that the concentrations involved are extremely small and, as a consequence, it is not currently possible to measure dioxins emissions continuously in real-time. Rather, it is necessary to sample over a period of hours and subsequently to analyse the collected sample with a high-resolution gas chromatography mass spectrometer (GC-MS).
Dioxins are not intentionally manufactured, he pointed out. They are unintentionally formed as by-products of chemical processes involving chlorine. Dioxins accumulate in the fatty tissues and are ingested in trace amounts within contaminated food. There are more than 200 different dioxins and furans, and many of them are considered to be highly toxic. The tolerable daily intake for dioxins has been set at two picograms per kilogramme of body mass.
In the UK, he said, emissions monitoring for dioxins is required by the Environment Agency for processes that have the potential to release these compounds and the monitoring requirement is generally to sample for around eight hours twice yearly, or more often if the process presents a higher level of risk.
A continuous sampler
At this point Middleton handed over to TCR Tecora director Maurizio Migliore. He explained: “Existing portable dioxins sampling equipment merely provides a ‘snapshot’ of the process from which it is not possible to quantify mass emissions and for this reason, as a specialist company in emissions sampling equipment, TCR Tecora decided to develop a system that would be permanently installed on a stack and would be able to sample for much longer periods of time.”
The new system, known as DECS (dioxins emissions continuous sampling), has received MCERTS and TUV approval. Migliore added: “The launch of DECS has provided regulators all over the world with the facility to require the creation of samples that represent total process dioxins emissions over much longer periods; up to one month. Secondly, DECS provides environmentally conscious businesses with the opportunity to generate emissions data that is far more informative and therefore of much greater value to regulators and the public.
Migliore explained that DECS was developed to mimic exactly the manual sampling methods and to comply with both European and US Standards. His colleague Paulo de Angelis provided a technical description of DECS, explaining that the European Standard EN1948-1 offers the facility to employ one of three methods; filter/condenser, dilution or cooled probe. However, he outlined the weaknesses associated with the latter two methods, describing how this led his development team to choose the filter/condenser method for DECS.
The filter/condenser method is also prescribed in the USEPA23 standard method. Expanding further on the advantages of the filter/condenser method, de Angelis said: “A heated isokinetic stack sampling probe, in conjunction with the external filter, provides the option to sample for hydrochloric acid, mercury and heavy metals in addition to dioxins and furans.”
The DECS sampling unit is permanently installed on a stack and operates automatically, which means that less labour is involved in the sampling process and the procedure is fully automatic so there is less opportunity for error and operators do not need to be highly trained experts.
TCR Tecora claims that, as a permanently installed fixture, DECS is less costly than occasional sampling. Furthermore, a control unit is installed on-site which can operate up to four samplers and thereby reduce the costs per stack even further. Remote access is available via the internet or intranet. The TCE Tecora speakers brought a DECS system to the Open University for the purposes of the seminar so that delegates could study the operation of the unit.
Summing up, Quantitech’s Duggan said, “Dioxin monitoring is clearly evolving and the launch of the DECS provides process operators and regulators with the ability to produce better quality data. It is interesting to note that visitors to a similar seminar in Paris have recently been required by their regulator to install long-term dioxins sampling equipment, so one suspects that similar circumstances may arise here in the UK.”
