Advanced Water Pressure Management

Advanced Water Pressure Management

Water Loss Reduction through Pressure Management

In 1997, El Nino triggered a serious water crisis in the Malaysian state of Selangor. An estimated 40% of water produced was not invoiced, with leakage estimated at 25% or half a million cubic meters per day. Halving the amount of physical losses would provide sufficient water to serve the equivalent of 1.5 million people and thereby avert a water shortage in Kuala Lumpur. The state government worked closely with a consortium led by a local firm in joint venture with an international operator. The contractor committed itself to reducing NRW (non-revenue water loss) by a specified amount. To date, the project has met with phenomenal success.

 

In Toronto, Canada, 8% of the utility’s water is lost, which is the equivalent of 15 Olympic–sized swimming pools every day (Clarke, Canada). This figure is not unusual and it is likely a lower percentage than most North American cities. On a global basis, it is estimated that 33 billion cubic meters of treated water is lost at an estimated cost of $15 billion US per year. North America seems to be lagging behind in its awareness of this issue but is gradually catching up to the rest of the world.

There are three components of non-revenue water. Physical (real) losses consist of leakage from the system and overflows at the utility’s storage tanks. They are caused by poor operations and maintenance, inadequate leakage control, and poor quality of underground assets. Commercial (apparent) losses are caused by customer meter under-registration and data handling errors as well as various forms of theft. Unbilled authorized consumption includes water used by the utility for operational purposes, water used for fire fighting, and water provided free to certain consumer groups.

Pressure Management Benefits

Leakage Reduction – If you have a leaking garden hose that has a pressure of 60 psi (4 Bar) and then you reduce the pressure to 30 psi (2 Bar), you will lose less water through that leak. The same principle we holds true in water utility’s distribution system. It is a well-known fact that if you decrease pressure within your system, you will reduce water loss. By reducing pressure by 1%, you will reduce leakage rates by 1.15% (variances can apply). The question is by how much are you able to reduce your pressure while maintaining adequate pressure to your customers. The resulting water loss savings relating to main and service lines can be incredible in both volume and cost.

i2o System Monitors and Control

The i2o system monitors and controls water pressure throughout a zone or network, and allows water companies to do two revolutionary things:

a)      Optimize water pressure continuously and automatically to meet agreed customer services levels throughout the network; and

b)      Adjust water pressure levels in any part of your network with a tap of the keyboard from any internet connection.

Advanced pressure management is achieved either by controlling PRVs in water zones or by controlling pumps feeding the network. We call the first PRV Control, and the second Pump Control. Pump Control allows water networks without PRVs (or networks already optimized at the water zone level) to achieve greater benefits from Advanced Pressure Management.

Advances Pressure Control

Pressure management is one of the most cost effective ways to control the amount of water lost in a system. This can implemented without affecting service levels when activated during off peak demand. It can also reduce consumption in networks. A small reduction in pressure can mean a significant reduction in real losses through leaks, a reduction in bursts and the extension of asset life.

Advanced pressure control is a simple cost effective adaption to an existing pressure control valve potentially yielding fantastic results with short payback periods. A simple interface and intelligent control system is able to be configured for Time, Flow or Closed loop control within single or multi feed networks.

Time Control

Pressure in the networks is modulated throughout the day from peak to minimum demand. The calculated profile (1 day or 7 day) based on historic data is tuned to give adequate pressure at the most critical points across the network. Pressure is typically reduced most at night during low demand periods and raised during the day to meet peak flow and overcome network head-loss.

Flow Modulation

Based on historic data a relationship of Pressure V Flow is programmed into the controller where the pressure supplied into the network is enough to overcome the head-losses for any given flow demand. The controller continually measures the flow rate and controls the supply pressure accordingly to ensure adequate pressure at the most critical points within the network. This technique will respond automatically to demand throughout the day.

Advanced pressure management at the PRV integrates hardware and software to optimize the pressure within a zone. The i2o designed this solution with one goal in mind: deliver the required level of water pressure, no more and no less, adapting throughout the day to actual usage and pressure needs. Unlike PRVs alone, which have fixed outlet pressures; our solutions continuously adjust the PRV outlet pressure according to each zone’s specific and current needs. The solution is made possible through the combination of:

1.   The careful monitoring of flow and pressure by i2o’s robust advanced loggers;

2.  Remote and automated control of pressure via the i2o controller and advanced pilot valve;

3.  Software that continuously learns and characteristics of the network, enabling the optimum PRV outlet pressure to be set to meet pressure requirements under all demand conditions, and

4.  An intuitive online user interface where managers can track their zones’ performance, respond to alarms and adjust pressure settings and schedules from their desktop.

In operating, PRV control smoothly and automatically raises and lowers the pressure delivered by the PRV throughout the day. The result: pressures in the zone are kept to a minimum while ensuring that there is adequate pressure for customers at all times, infrastructure is protected, and leakage, burst frequency expenses all drop significantly.

Closed Loop Control

The ultimate in advanced pressure control. This technique can be used on single or multiple feed networks and can deal simultaneously with several critical points, meeting the requirements of each. Advanced pressure controllers are install and commissioned on each PRV and remote control data logger installed at the critical points. A target pressure or pressure profile is determined at the critical points. Using the GSM network as a communications medium, control messages are sent from the critical point to the controllers adjusting the supply pressure to ensure optimized pressure all the time.

Balancing the supplies on multi-feed networks is possible, as is remote communications to change target pressure at any time or manual system control.