| | 
Southern Water introduced
an advanced control system
for six of its wastewater treatment
plants in the Chichester area, UK.
The real-time control system
will lead to carbon emission
reductions of around 25%. An advanced control system for wastewater treatment plants is being introduced at six of Southern Water's treatment plants in the Chichester area. This is one of the first applications ofreal-time control in the UK. It is the result of MWH and its joint venture organisation, 4 Delivery (4D), collaborating with Southern Waterto meet its AMP 4 wastewater standards. This will minimise capital expenditure, maximise performance and lead to carbon emission reductionsof around 25% equivalent to taking 600 cars off the road.
AjayNair, MWH Principal Process Engineer seconded to the 4D JV explains, "Under traditional control systems, it is not possible to make use of the safety factors built into a treatment works to take account of thewastewater variability and seasonal changes. By controlling a treatment plant to match the actual conditions experienced at that time, rather than an average or minimum condition, optimum treatment and energy consumption can be provided. The term real time control has been used to describe this particular method of aeration control."
For AMP4, Southern Water was challenged with providing Total Nitrogen Removalat six of their treatment plants (Budds Farm, Peel Common, Chichester, Sidlesham, Thornham and Bosham). The first three plants already useenergy intensive activated sludge processes. If these processes had been combined with total nitrogen removal without real time control it would have resulted in at least a doubling of energy use plus significant additional carbon emissions due to the need for methanol dosing.
Therefore, to minimise the negative impacts on the environment and the company and to ensure it met the new regulatory compliance requirements, Southern Water and 4D have worked towards reducing the carbon footprint associated with each of these new plants by using real-time control. These will be amongst the first systems of this kind to usereal time control in the UK.
David Craft, Principal Process Engineer of Southern Water explains; "Currently treated wastewater standards are dictated by the short to medium term impact on the receivingwater body. Until recently, no consideration was taken of the carbon impact of the more energy intensive processes needed to meet tighter standards - creating a regulatory vicious circle. However, it would havebeen irresponsible not to have chosen this innovative method as the increase in carbon emissions associated with the treatment plants to meet the new standards at Chichester, Peel Common and Budds Farm would have otherwise been the equivalent of 2,500 extra cars on the road."
He adds that in addition to significant carbon reduction throughthe use of real time control, an improvement in compliance is also achieved at the same time as reducing operational costs, as the plant reacts instantly to changes in the influent and constantly operates undera very stable condition.
By implementing the control systems,it is anticipated that carbon emission savings that can be achieved onall three of the schemes will be around 25% (equivalent to 600 less cars). In addition to carbon reduction the cost benefit associated withthe energy and methanol savings is also significant, providing additional financial incentives to install real time control systems. Currently, the partnership has selected a preferred supplier and a preferredmethod of the advanced control system to minimise capital expenditureand maximise performance. However, Nair is keen to stress that although, financial drivers are still very relevant, the sense of urgency around climate change is such that a greater emphasis is being placed upon carbon reduction techniques as the primary filter.
NarinderSunner, MWH Principal Process Engineer leading this initiative says; "Both Southern Water and 4D have demonstrated their commitment to pioneering technologies that actively reduce carbon emissions to meet the compliance standards applied. The work conducted to date sets the foundations for future energy reduction strategies not only for Southern Water, but for all UK water utilities if our national target of a 26 - 32% reduction in CO2 by 2020 is to be realistically achieved."
| |
