We are proud to provide a sustainable, affordable, clean and safe water supply and to manage and treat the waste water returned to us in a way that protects the environment.
| Investigating solutions available for recycling water treatment works sludge | Leak detection | Meter materials | Remote service reservoir inspection and cleaning | Water Industry Achievement Awards winner |
Meter materials
As part of our meter strategy the types of meters that are available to be installed, as part of our meter option or meter replacement programmes, have been investigated.
Historically most water meters were manufactured with metal bodies and a mixture of materials within the internal workings, this made meters heavy and not particularly environmentally friendly.
As technology has advanced, different materials have become available, however, it is essential that the materials used to construct the meters are fully tested to ensure they are acceptable for use with drinking water and also resistant to any ground contamination. Meter manufacturers have now developed a meter body made of a composite type material, and our current meter supplier has recently received certification for their domestic manifold meter confirming that it can be used in underground situations.
As a result we have now switched from brass bodied manifold meters to composite bodied meters, these are lighter weight, a slightly lower cost are also more friendly to the environment during manufacture.
NWL and Byzak were jointly presented with the award for ‘Most Innovative Use of an Existing Technology’, at the 2010 Water Industry Achievement Awards this year. The category rewarded the most innovative application of an existing product or technology that has been commercially available since before February 2009.
The Retroflo Pump Control System was developed with the multi-disciplinary engineering company Byzak, as a solution to the build-up of debris on pump impellors leading to pumps operating inefficiently and ultimately blocking. It was developed to utilise the full range of pumping data available, through continuous monitoring of the pump characteristics over a range of wet well levels and pump speeds.
The new system is uniquely able to compare real-time data against benchmarked data to pre-empt blockage situations and implement automated corrective action in the form of a rapid reversal sequences. Solids build-up on the pump impeller is immediately detected, and a self-cleansing sequence initiated.
The Retroflo RPC_2000 has demonstrated its ability, in some of the toughest conditions available within the Northumbrian Water sewerage network. In some cases sites running the Retroflo system have recorded a 100% reduction in blockages, along with optimised process control, the virtual elimination of reactive maintenance call-outs and a substantial reduction in pump motor electrical consumption.
Sustainability benefits were at the forefront of the design process and the system was intended to be retro-fitted to work in conjunction with existing components to improve operational performance and energy efficiency. In operation at various sites, the system has recorded impressive results, including fewer or no operator call-outs, cleaner wells and the security of consented flow, enabling pumping installations to operate at maximum effectiveness.
The Retroflo RPC_2000 was installed at Blyth Bates Sewage Pumping station with significant results. Electrical energy consumption at the site was high with an EPI (Energy Performance Index) of 7.74 (Unit of measurement is kWh per ML pumped per metre head pumped). Operator call-outs to deal with blocked pumps involved a vehicle journey of typically 30 miles, repeated once a week. Following the installation of the system EPI is now recorded at 5.66, and there were no blockages in 2009 compared with weekly blockages in 2008.
The system has now been installed at over ten sites in the Northumbrian Water region and is also installed and in operation at pumping stations operated by Scottish Water, United Utilities and South West Water.
Constantly providing clean drinking water for the people and industry of Northeast England requires the removal of a wide variety of contaminants from water taken from rivers, reservoirs and underground reserves.
As regulation has tightened and population has grown, the amount of sludge that we produce as a by-product of the water treatment process has increased, to around 67,000 tonnes each year.
To help find a beneficial disposal route for this sludge we are working with Teesside University through the Collaborative Innovation Partnership programme. The Collaborative Innovation Partnership programme brings together academia and industry to focus expertise on an industrial problem. The Collaborative Innovation Partnership associate will work closely with both parties to transfer knowledge and find a solution. The partnership will allow us to forge close relationships between key departments within Teesside University, notably The National Industrial Symbiosis Programme (NISP) and The Clean Environment Management Centre (CLEMANCE), which will facilitate further research.
The approach we have taken to the project is structures in order to identify and apply potential solutions; this comprises initial research, trials, economic analysis and recommendations as to the long term viability of the identified solutions.
The project itself has identified six available options and these are being researched and trialled:
• in agriculture, with investigations being made as to the viability of composting and that of direct agricultural application,
• as a construction material, through incorporation into bricks,
• as a landscaping material,
• for use in contaminated land reclamation,
• to support the cultivation of bio fuel crops on Brownfield, and
• in the production of high quality topsoil.
Once detailed trials have been conducted economic analysis will then take place.
The long term goal of the partnership is to identify a solution for a problem faced by not only our company but for the entire industry.
Leak detection is a vital part of the work we do as a company as water efficiency is a major part of our business, reducing our leakage rate will help us reduce our CO2 emissions and we are set annual targets by OfWat to reduce our leakage rates.
In order to detect leaks it is vital that we make use of the most effective and efficient methods available. There are a number of methods to available to employ, these include acoustic methods, non acoustic methods, step and drop testing and we are currently trialling tracer gas detection.
Acoustic methods, these are all affected by pipe material and pressure.
• Sounding – Sounding sticks or ground microphones can be used to determine leak location. Experience is needed to distinguish leak noise from background noise.
• Leak noise correlation and logging – Correlators compare the time taken for a leak noise to travel to two separate sensors and estimate the leak location. Loggers monitor leak noise for extended periods and can indicate the general area of a leak.
Non acoustic methods, these are usually performed at night to minimise disruption.
• Leak-Finder – A bladder is inserted into the pipe and inflated. Pressure drops detected past the point of inflation indicate leakage.
• Step and drop testing – These tests involve changes to the flow or pressure across a specific metered supply area. Leaks will cause higher flows and lower pressures.
Tracer gas detection trials
We conducted trials in November 2009 which involved injecting an inert hydrogen/nitrogen gas mixture into the water supply of a property. A probe is used to locate any leak by sensing the hydrogen that has seeped from the leak to the surface. The advantage to this method is that it us unaffected by pipe material or size so is a good alternative to acoustic methods, although leaks under concrete may be harder to detect as the gas has no direct route to the surface.
We are always looking for new ways to detect leaks as accurately detecting and locating leaks will reduce the time it takes us to repair the pipe and minimise water loss and disruption to our customers.
• Technical evaluation of ‘live’ inspection and cleaning service using remotely operated vehicles (ROVs), from Panton McLeod.
• Clear objectives of technical trial.
• Demonstrate acceptable inspection and cleaning of treated water reservoirs that cannot be taken out of service due to lack of adequate bypass and valving arrangements; and
• Delivery of a more cost-effective solution for the cleaning and inspection of treated water reservoirs generally.
• Straightforward trial of the service on real assets, with the appropriate safety precautions in place; independent assessment of cleaning and inspection.
• Both inspection and cleaning found to be very effective, exceeding expectations of many observers.
• Equipment now recommended for use in NWL – saving money and affording access to previously inaccessible locations.