Towards on-line monitoring of metallic wastewater


In line with environmental regulations, a newly developed sensor technology has been designed, developed and evaluated for on-line monitoring of metal-containing waste streams.

Conventional waste treatment technologies may become inefficient, as they need to keep pace with the ever-decreasing concentration limits (allowed by regulations) of pollutants found in industrial effluents. Thereby, a new, integrated approach would be more beneficial than the emission reduction through "end-of-pipe" treatment methodologies.

Answering this need, the MEWAPREV project focused on developing on-line integrated processes for the prevention of metal waste from industrial effluents.

The project work involved the use of fully controlled (lab-on-chip) units - including Supported Liquid Membranes (SLM) and Modified Electrodialysis (MED) in combination with 3-dimensional cathode cells. Within this context, researchers designed an innovative isotachophoresis (ITP) injector geometry that allows variable volume sample injections to be reliably and simply performed. The prototype units were made of polymethylmethacrylate (PMMA) material and fabricated with the aid of a rapid direct micromachining technique.

These microdevices were tested in terms of their suitability for on-line monitoring, using a specially designed fluid handling system that provides automatic delivery of samples and electrolytes. On the basis of these assessment results, an industrial MEWAPREV monitoring system was developed for on-line analysis of aqueous sample streams. The system is fully controlled through suitably developed software program.

Additionally, novel electrolyte systems were also designed for the separation of numerous metal ions, such as - Ca, Mg, Mn, Cr, Co, Fe, Ni, Zn and Cu. These systems may complement the analysis of provided metal waste streams. Apart from the metal ions found in industrial waste streams, the sensor technology can be used for the analysis of other ionic species from various industries.

The prototype has already been subjected to a joint patent application with Siemens. Collaborations are sought with potential partners interested in on-line process control - as well as chemical industries engaged in measuring concentrations of ionic species found in aqueous streams.

For further information, contact -

Peter Fielden
Professor of Analytical Science
Tel: Tel: +44 (0) 161 200 4889
Fax: +44 (0) 161 200 4911