The financial constraints of Ofwat’s final determinations for PR19 now mean that water companies not only have to reduce phosphorus discharge levels but also ensure that this is achieved as cost effectively as possible. Here, Daniel Parry, Head of Sales Municipal and Industrial, at Veolia Water Technologies UK (VWT UK), looks at this, along with other key challenges facing the industry and explores some of the potential solutions.
Phosphorus is a key issue in wastewater management due to the impact it has on the environment and the related targets that must be met to minimise this harm. Phosphorus can enter watercourses from a variety of sources such as excess fertilisers being washed into rivers as well as discharges from sewage treatment. If large quantities of phosphorus reach streams, rivers and lakes it can cause the water to become too nutrient rich and trigger algae blooms. This can deplete the oxygen in the water, resulting in the death of fish and other aquatic wildlife, and also block sunlight from reaching water based plants.
However, it is important to consider that phosphorus is a finite, valuable resource. It is a key ingredient in agricultural fertiliser and animal feed, and it is primarily obtained from mining. None of these mines are located in the UK or even Europe, meaning there is a significant environmental impact when importing from countries such as Morocco, China or the United States. Therefore, improving how it is used and managed in the UK will have wider positive effects for the environment.
For UK water companies, the current Asset Management Period (AMP7), which runs up to the end of 2024, presents a move away from ‘business as usual’ as they must meet stringent new targets set by Ofwat. This includes making water supplies more resilient, reducing leaks and striving for carbon neutrality by 2030. However, these targets must also be met while reducing customers’ bills by 12% before inflation and providing financial support for those who struggle to pay.
Alongside this is the Government’s ambitious Water Industry National Environment Programme (WINEP), a programme of investment that the Environment Agency expects all 20 water companies operating in England to complete by the end of 2024. This includes the implementation of approximately 1000 new final effluent phosphorus (P) consents as part of efforts to protect and improve at least 6000 km of watercourses, bathing waters, shellfish sites, nature conservation sites, as well as enhancing the biodiversity of nearly 900 km of river. As such, the scale of the work required in this AMP is significant and water companies will invest as much as £5 billion into the protection of the natural environment in the five year period up to the end of 2024.
Meeting the new P consent standards
There are a number of approaches that water companies can take to ensure they meet the required targets in the most cost effective way. However, there is no single solution, and an integrated and holistic approach may be the most appropriate way to reap the benefits.
Firstly, water companies can engage with local landowners and farmers to limit the amount of fertiliser runoff from fields into the water network. However, farming is not the only source of phosphorus, and as a key part of agriculture it cannot be eliminated completely.
In terms of making the best use of the existing treatment assets and resources, it may be possible for water companies to optimise their processes to increase their effectiveness and achieve higher levels of treatment. Advances in technology have made it easier to monitor and improve the performance of wastewater treatment plants, and even the wider wastewater network. The growth of connected technologies means it is possible to use sensors to collect real-time data about the system’s performance. In partnership with a specialist, this information can be used to identify where improvements can be made. Sophisticated algorithm-based optimisation such as that provided by Veolia Water Technologies’ Hubgrade digital management system can constantly monitor the technology and wastewater characteristics to maximise efficiency, reduce OPEX and allow the performance to remain at an optimal level.
However, where existing processes or plants cannot meet the new standards, there are a range of small footprint retrofit options, including enhanced tertiary treatments. By choosing a retrofit approach to make use of existing assets water companies can make capital expenditure (CAPEX) savings on installation and, with the right technology, reduce operational expenditure (OPEX) going forward.
There are a number of solutions on the market that are ideal for phosphorus removal and offer flexibility and space efficiency. Two of the most common approaches are a ballasted flocculation process or a woven cloth filter system.
For example, our Actiflo process offers a very high flow rate and a compact footprint. In fact, the footprint is four to eight times smaller than lamella or dissolved air flotation (DAF) clarifiers and up to 50 times smaller than conventional clarification systems. Similarly, our Hydrotech Discfilter is typically 50 to 75% smaller than traditional filtration processes but provides two to three times more filter area compared to alternative technologies of the same external dimensions. Both technologies are proven to meet very tight phosphorus discharge levels.
Alternatively, for water companies looking to reduce costs further, phosphorus recovery offers a way to meet the stringent targets while reducing waste disposal costs and creating a new revenue stream. This technology allows the phosphorus to be extracted from the wastewater as the phosphate mineral struvite. This can then be sold for reuse in fertiliser production, creating a circular economy in the use of this valuable resource. The added revenue also helps offset the initial capital cost, so the payback period of this technology is shorter. Implementing a recovery process also helps reduce costs further and lowers the environmental impact through reduced sludge production.
Future of phosphorus
It is important that water companies take a long term view when investing in new plant and equipment to ensure the chosen solutions will allow easy and cost effective upgrades to meet future demands. Although it can be tempting to focus on the immediate obligations, selecting the lowest cost solution that meets those requirements is not always the best solution. Higher quality systems that offer greater flexibility or capacity can also provide greater long term value.
With so many challenges currently facing water companies – it can be incredibly valuable to partner with a water treatment specialist. Collaborating with a team that has the knowledge and technical insight as well as a wide range of solutions to draw upon will mean companies are in the best possible position to formulate a strategy that benefits both the environment and its own operations.
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