Established over 25 years ago, WPL is recognised as an international leader in engineering design, manufacture and supply of packaged wastewater treatment process solutions. Offering standardised products and bespoke process solutions for the cost-effective, on-site treatment of wastewater treatment, WPL has delivered on-site process solutions to the domestic, commercial and industrial markets globally. WPL ensure that wastewater treatment plants are designed and proven to exceed all current or proposed discharge consent standards enforced by the UK Environment Agency, SEPA or other regulatory bodies, the directors, managers and staff are committed to ensuring adherence to the following: ISO 9001 certification; OSAS 18001:2007 certification and ISO 14001 certification.
Miss Lianne Ayling
Units 1 Aston Road
WPL's Energy-efficient Wastewater Solutions
WPL Limited provides innovative and reliable wastewater treatment, rainwater harvesting and grease management systems for domestic, commercial and industrial markets as well as holding a prominent position as a supplier to the water utilities.
As an internationally recognised leader in the design, manufacture and supply of both standardised, and bespoke environmental wastewater solutions, WPL is dedicated to ensure the provision of high quality products and services.
As part of an ongoing research and development program, WPL's engineering team has undertaken substantive research and development into energy saving options for their HiPAF SAF (Submerged Aerated Filter) sewage treatment range. The objective of this research was to reduce whole life costs for their customers by reducing energy consumption and thereby their carbon footprint. These savings could be applied to commercial applications as well as municipal and were in line with the Water Utility 2020 initiatives.
Over an 18 month period energy consumption and performance were monitored and recorded from sites with WPL HiPAFs. This real data confirmed assumptions made during the design and feasibility stage and centres around the design of the aeration system and various scouring regimes, along with trials of different media configurations and blower efficiency.
The HiPAF already benefits from being a low maintenance treatment solution, with the emphasis on reducing moving mechanical parts within the hostile environment of the treatment plant. However, savings of between 15% and 50% on electricity consumption provide a significant reduction in whole life costs, particularly in higher population equivalent applications. Dual speed blowers utilising variable speed drives is one option that has had favourable reviews from clients, and other design efficiencies both with regard to blower design and media configuration have brought significant savings to some existing clientele.
Case Study - Beaconsfield MSA Service Station
The new M40 Service Station at Beaconsfield required a wastewater treatment solution back in 2009. WPL's engineering team designed and provided a bespoke HiPAF modular sewage treatment solution which incorporated a below ground 150m³ primary tank complete with integral pump station, modular SAF Biozone units, a lamella settlement tank, and a tertiary Microscreen filtration system. The total package combined efficient processing, reliability and a robust design whilst minimising visual impact on the landscape.
The Sewage Treatment Process
The bespoke Beaconsfield solution is designed to treat wastewater from a maximum population equivalent of 3800 based on the ammonia load of 30.4kg/d that was specified by the design consultants. As such, the air compressors have been sized to deliver sufficient air to supply oxygen for the nitrifiers responsible for removing the ammonia load, whilst simultaneously providing enough air to scour the biozone media and preventing the biofilm from becoming too thick and anaerobic. Only two compressors are ever running at any time.
Since commissioning Beaconsfield MSA effluent treatment plant in March 2009, flow data captured from site has revealed that the site is currently operating between 20-30% of full design load capacity. This has lead WPL to consider the impacts and consequences of attempting to reduce air supply in line with operating flows and loads as opposed to peak design flows and loads. The benefits to the customer would be significant savings on the electricity bills.
The preferred method of reducing energy consumption at Beaconsfield MSA would be to reduce the air supply during periods of low activity and thus low flows. From a 24 hour intensive flow monitoring survey carried out, it was identified that between 11pm and 7am of the following morning, flow to the foul water treatment plant effectively stopped. During this period of time, it is proposed that the air supply to the biozones be reduced by 50%. This would be achieved by manipulating the air supply such that both actuators open simultaneously, allowing the air from a single compressor to deliver air to both process streams. This would involve reconfiguring the control panel accordingly.
Shutting down one compressor on 8 hours per day would yield a saving of 144 units per day. Based on 10 pence per unit this could potentially yield a saving of over £5000 per year.
Jerry Storer, Senior Operations Executive for Extra MSA stated: "WPL have completed significant research into the energy consumption of the HiPAF plant sited at our service station on the M40, Beaconsfield. This research has proven that optimising the air supply to our system can be achieved without compromising our EA consent and has therefore saved us considerable costs on our electricity bills."
Currently WPL's wastewater solution is working at the above level of electricity savings having reduced the air supply, although research continues into the possibility of increasing this saving, up to £10,000 per year, by reducing the blower use again during the periods of low flow.
Real data research allowed WPL to find a way to make savings for their customers by reducing the air supply to their HiPAF sewage treatment plants therefore reducing the blower electricity usage. Case in point, this approach has saved MSA Extra Services Ltd up to £5,000 a year.
WPL's engineers are continuing their product development research into the blower efficiency of their sewage treatment plants whilst also looking at the design of the aeration system and various scouring regimes, along with trials of different media configurations, to be able to offer the lowest whole life costs for their customers.
For further information please email WPL Ltd