With the announcement of Ofwats’s final determinations going into AMP7 there is increasing and imminent pressure facing water companies in the UK. Tighter phosphorus (P) consents set out in the Water Industry National Environment Programme (WINEP) and restricted spending power are both set to play a key part in the new AMP period, which will in turn place a significant demand on water companies and their respective supply chains.
With this in mind, we recently gathered together Veolia Water Technologies’ global experts along with UK water company and supply chain representatives to talk about the future of Phosphorus removal.
Our first speaker of the day was Reid Staton, Actiflo Product Manager for VWT USA. Reid began by emphasising the need for a consistent phosphorus removal process flexible enough to cope with dramatic changes to influent total phosphorus (TP) as well as adapting to the possible implementation of even more stringent limits in the future. In particular, Reid highlighted two of VWT’s established approaches to P removal, enhanced tertiary treatment technologies Actiflo and Discfilter and how they can be used to achieve ever tighter phosphorus consents.
Actiflo is a small footprint sand ballasted flocculation system offering a high flow rate while Discfilter is a highly durable woven cloth filter system with a small footprint and an extensive installed reference base. Both of these technologies are widely used throughout the USA and Europe, and allow for varying influent TP and total suspended solids (TSS) levels to be effectively treated. Both technologies are also proven to meet TP consents of less than 0.1 mg/L.
We also heard from Kim Sørensen, Senior Process and Technology Expert at VWT Denmark and Henik A. Rønnow Thomsen, Senior Process Expert at VWT Denmark who looked at VWT’s experience with Biological P removal and co-precipitation in Activated Sludge plants in Europe.
Currently, Biological P removal is not as widely used in the UK as in other parts of the world; however it has the potential to reduce coagulant consumption, chemical sludge levels and subsequently costs. Over the years, Enhanced Biological P Removal (EBPR) design has been optimised by reducing the anaerobic volume to reduce footprint and cost; however this has had a detrimental effect on their performance. It is now clear that Biological P removal cannot be sped up. However, if water companies have the facilities to operate as an EBPR plant or in complement to chemical precipitation at times when flow, load and influent TP are reduced, for example at night, this small operating change can radically reduce costs.
The experts highlighted that one way that this can be properly managed is through the use of digital services, like VWT’s AQUAVISTA™ Plant, to optimise water treatment plants and switch effectively between Biological P removal and conventional treatment at the right times by creating anaerobic conditions. Through the accurate monitoring of influent TP, flow rates and P output, a cloud based system like AQUAVISTA™ Plant can switch instantly between Biological and non-Biological P removal to optimise costs whilst also monitoring and maintaining a resultant P consent of less than that the required.
Finally we heard from Cedric Merbaki, Research & Innovation Project Manager and Hughes Humbert, Senior Process and Technology Expert, both from VWT France, who discussed some of the research and development that is in progress for P removal technology of the future. Cedric highlighted the importance of P recovery in Western Europe as Phosphorus is not available longer mined on the continent, despite it being a popular fertiliser product. As such, P recovery is a concept adopted in several rural wastewater treatment plants but experts are currently looking into ways in which P recovery can become more commonplace.
Currently the best way to harvest P is to use an absorbent material which will remove the P from the wastewater and can then be formed into pellets and sold as fertiliser. This could be a viable way for wastewater companies to utilise a bi-product of the treatment process in order to cut costs. One such product, Apatite pellets are already in VWT’s portfolio. VWT is now trying to develop a new absorbent based on reused materials like industrial by-products, for example Bauxite from the aluminium industry, Biochar, Fly ash and Bottom ash. While all of these are known to work effectively, each comes with its own challenges, whether that is inconsistency of substance or that the substance itself is hard to come by. In their further experimentation, the experts at VWT have held pilot tests on a number of other substances that hold potential for the future, including crab shell, which has proven to be a viable solution for coastal facilities.
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