Wastewater monitoring from your browser

01Nov

Ethernet communications have increased the reliability and improved the visibility of wastewater reporting at Newcastle International Airport

Newcastle International Airport (NIA) is one of the UK’s fastest growing regional airports and is the dominant airport in the North East of England. Since the arrival of low cost airlines in 2003, passenger numbers have soared - with the airport handling over 68,000 flights and 5.2 million passengers in 2005. NIA operates an Environmental Management System at the airport in line with the ISO 14001 standard, and one important aspect of this is to ensure that contaminated surface water does not enter the local watercourses.

Surface waste is at risk of being contaminated with de-icing fluid, which is used both on the airfield and aircraft flight surfaces. In excess of £1m has been invested in the polluted water diversion system on site, and resources continue to be allocated, including a series of storage lagoons on the north and south sides of the airport. The storage lagoons provide vital attenuation for surface water, where biodegradation can occur before it is discharged at a controlled rate to either foul or surface water.

Before entering the lagoons, water initially enters a penstock, where it is monitored for total organic carbon. If the water is deemed clean, then it will be diverted to the local watercourse; but dirty water, on the other hand, is directed to the lagoon. A further test takes place at the discharge end of the lagoon to determine whether it is sent to sewer or watercourse.

The lagoons and associated water quality monitors require continuous monitoring and regular maintenance to ensure correct operation. It is also critical that relevant personnel have access to various operational parameters as well as to the status of pumps, penstocks and so on.

Previously, a single PC collected data from the lagoons using conventional modems to transmit data over the airport’s telephone network. The main problem with this method was poor connection reliability and poor access to data. Due to the fact that the modems went off line when data was not being requested, information was not always readily available. Improvements were therefore sought to improve the reliability and accessibility of the system.

Astral Control Services supplies, installs and maintains automatic control systems, and is contracted to maintain the existing control equipment at NIA. As part of an upgrade to the building management system (BMS) commencing in 2006, the company was instructed to connect the remote wastewater treatment processes at the three lagoons to the new BMS with a view to improving visibility and reliability.

Cylon Unitron PLCs were installed at each of the three lagoons, and a Westermo SDW-550 Ethernet switch connects the remote PLCs back to the main BMS controller within the main terminal building. From here, the information is made available via the airport intranet, whilst the data collected at the lagoons is transmitted via Ethernet TCP/IP over the existing telephone network. Two Westermo DDW-100 line extenders are used (one at the lagoon and one in the control panel) to extend the network to reach the Penstock 3 lagoon, which is around 5km from the main terminal. Once again, the existing telephone network is used.

The use of web technology means that the BMS can be monitored or controlled from existing web browsers without the need for a special client software installation. Moreover, the use of web technologies allows any number of users to be supported and enables the smallest remote sites to have some local monitoring and delegated control.

Westermo’s DDW-100 utilises existing wiring to link remote sites to a central industrial Ethernet network, removing the need for a special fibre optic cable installation. Indeed, the line extenders use the existing telephone cabling system to extend the centralised TCP/IP network (within the terminal building) out onto the runway. Essentially, the Cylon BMS can make the information from the remote lagoons available seamlessly via the airport intranet to anyone with the correct username and password.

Having this data available is critical to meeting environmental requirements at the airport. Improved visibility enables not only the BMS services manager to monitor the results, but also ensures that the environmental officer, finance director and other internal members of staff gain access to the data via the airport’s intranet from any web browser.