Wessex Water Awards COD Contract to HACH LANGE

The COD (chemical oxygen demand) test is one of the most important analyses conducted by the wastewater sector. It is a measure of organic pollution, and is the most frequently mentioned parameter in European environmental legislation.

Wessex Water’s laboratory at Saltford near Bristol performs a large number of COD tests and senior lab services technician Alan O’Reilly says “HACH LANGE has been awarded a 3-year contract to supply COD reagents following a thorough evaluation of equipment and reagent options. We require a system which provides high levels of accuracy and reliability coupled with a fast process that is able to accommodate a high sample throughput. In addition, HACH LANGE’s reagent recycling service was a significant factor in the final decision.”

COD reagents are supplied in a ready-to-use cuvette so that users simply add a sample and replace the cap. The cuvette is placed in a heater for 2 hours, after which time the intensity of colour in the solution is directly proportional to the COD value in the sample. The cuvette is bar-coded so that it is recognised automatically by a HACH LANGE Spectrophotometer, which substantially reduces potential for operator error.

The Hach COD test follows the ISO 15705 standard method exactly, with all reagents supplied ready-to-use, in precisely the correct amounts in a small cuvette.

Commenting on the agreement with Wessex Water, laboratory sales manager for HACH LANGE Mathew Dillon said “We recently announced a similar agreement with the Environment Agency for the supply of COD reagents so it is particularly pleasing that Wessex Water has also been added to our long list of highly reputable clients. The quality and reliability of our spectrophotometers, heating block and COD reagents mean that customers can rely on the correct reading every time. The test is extremely simple to perform and it incorporates several unique features designed to substantially eliminate human error.

We are also very pleased to note that our recycling service played an important role in Wessex Water’s decision. We operate the service on a not-for-profit basis in compliance with the new regulations on hazardous waste management. Our Recycling Centre facilitates recovery of materials from HACH LANGE reagent tubes including the glass itself in addition to components such as Mercury, Silver and Chromium. In fact, over 70% of returned materials are either re-used or recycled.” The HACH LANGE European recycling centre in Germany is available for customer audit.