We get plenty of rain to collect & store, why do we need to treat & recycle sewage effluent for drinking water?
Effluent recycling is only used in severe drought-stricken parts of the world such as California, Namibia and parts of Australia. Why do we need it in England where there is plenty of rain-water that could be collected and stored? There must be better more sustainable options.
Customers have advised water companies in the South East that they would prefer to reduce leakage and develop more natural solutions such as storing water underground, or in reservoirs, rather than effluent recycling, which they are concerned requires a lot of energy and chemicals. They also advised further reassurance would be needed on water quality.
Climate change models show that we can expect more winter rainfall, including extreme events that will cause flooding. Why not investigate and identify where excess flow could be used to top up confined underground aquifers in winter and stored for use in dry summers? When water is stored underground it is not subject to evaporation. Why is the River Test groundwater recharge scheme not being considered until 2041?
If there are not enough suitable confined aquifers, then why not build and store excess winter water in reservoirs nearer to where the water is needed, rather than build a 40km pipeline. This could help to reduce flood risk.
While we support better water management to protect against climate change and preserve our chalk stream, a more phased approach can be taken, developing a number of smaller more sustainable solutions which work with climate change to meet the need for drinking water. Rather than rush into environmentally unfriendly solutions such as effluent recycling. This will give time to fully investigate the impacts on the environment and for technological advances in treatment to be developed to reduce the energy needed to make it a more sustainable option.
Portsmouth Water’s plan indicates that from 2040 transfers to Southern Water will reduce significantly and may stop altogether by 2049 because Southern Water will have new sources coming into operation. Therefore, we are looking for environmentally friendly solutions that can bridge the gap in supplies from 2030 to 2040. Not all decisions need to be made now, we just need to make the right decisions. The Regional Plan makes it clear that there is the opportunity to make further decisions at later dates, as the plans are reviewed every 5 years, with another key decision point being around 2030. One huge solution is not needed straight away. A decision about effluent recycling via Havant Thicket Reservoir could be delayed, until we know how effective other measures have been and what other solutions are viable.
Effluent recycling should only be considered as a last resort, when more environmentally friendly solutions have been fully investigated. If effluent recycling were the only solution, why not recycle the effluent from sewage treatment works (STW) closer to where the water is needed, and where there is not a saline intrusion issue. Then the recycled water could be stored in underground aquifers (as is done in other countries) or returned to rivers to help support low flows in summer. The latter could have benefits for biodiversity. For example;
- Why isn’t Peel Common STW being considered more actively when Southern Water’s own reports indicate that it would have more of a benefit to our coastal waters, and Ofwat have agreed to fund further development of that scheme.
- Why is the Woolston STW effluent recycling option not considered until 2050 when it is much closer to where the water is needed in Southampton?
Southern Water has a very poor track record on pollution incidents and compliance with Regulations. Will you trust them to properly treat the recycled effluent?
Southern Water propose to use the new Havant Thicket Reservoir as an environmental buffer lake into which it will discharge a minimum of 3 Olympic sized swimming pools of recycled effluent every day of the year. When demand is high in the future it wants to be able to discharge up to 60 million litres per day, which equates to pumping 24 Olympic sized swimming pools of recycled water into the reservoir each day.
They want to use the reservoir as a buffer lake, so that if the new treatment plant fails, or is not operated properly, the polluted water will go into the reservoir. Southern Water’s own report indicated that the extent of removal of the proposed treatment plant is assumed to be 82%, with a table showing it is more effective at removing some pollutants than others.
To operate effectively the treatment method proposed requires a fairly consistent quality of effluent, but in reality, effluent quality from the sewage works will be variable. The operation of the membranes is a very precise and delicate process which needs careful management by skilled operators. Given Southern Water’s poor track record would you trust them to provide the very careful management needed? Or to pay the high cost of maintenance of the plant to ensure that it runs efficiently?
The treated water will only be routinely analysed for parameters that are easy to test for as indicators of the effectiveness of the process, as testing for many of the contaminants that can be in sewage effluent is difficult and time consuming. By the time less frequent, more detailed test results are received from the laboratory it will be too late, the contaminants will already be in the reservoir.
When asked, Southern Water indicated that they had no plans to require improvements to industrial and commercial discharges into the sewers which feed into the Budds Farm Sewage Works. Yet good practice in other countries, and their own report referred to the need for additional source control at Budds Farm to manage the discharge of high loads of metals or other contaminants impacting upon the treatment process. The text also confirmed that this could pose public health and environmental risks not controlled at source. The same Southern Water report flagged that there is a risk associated with the future deterioration in effluent quality at Budds Farm because of increased trade effluent.
The water taken from the reservoir will taste different. If you know it contains treated recycled effluent, will you drink the water? If not, what are the impacts for you of buying bottled water and for the environment?
The water from the Havant Thicket Reservoir containing recycled effluent mixed with spring water will be distributed to Portsmouth Water customers via the Farlington Water Treatment Works, and to Southern Water customers via the Otterbourne Water Treatment Works.
As the water will come from a different source it is very likely to taste different when it comes out of your tap. There has been very little public engagement about whether customers will be confident to drink the water. Some people have indicated that they will not want to drink the water and will turn to bottled water instead.
This could adversely impact the elderly, young families, and anyone on low incomes if they reject the water for drinking and instead buy bottled water.
There is also the significant environmental cost of manufacturing, transporting bulky/ heavy bottles and disposing of the huge numbers of plastic bottles, which rejection of tap water for drinking could create.
It will require a large amount of infrastructure to be built, plus lots of chemicals and energy to operate daily, which us the customers will have to pay for in our bills.
In addition to a new large effluent recycling treatment plant at Broadmarsh in Havant they will need to construct 3 large pipelines; Budds Farm to Broadmarsh, Broadmarsh to Havant Thicket Reservoir, as well as a 40km pipeline from the reservoir to Otterbourne. Multiple new pumping stations will need to be built and operated to pump the water along these pipelines. All of this construction work will be very expensive and have a high energy and carbon footprint.
In addition, even when the water is not needed Southern Water have indicated that they will still need to treat and pump a minimum of 3 Olympic sized swimming pools of recycled effluent every day of the year to keep the treatment plant and pipelines sweet. When demand is high in the future, they want to be able to treat and pump up to 60 million litres per day, which equates to 24 Olympic sized swimming pools of recycled water into the reservoir each day. The cost of the large amount of chemicals needed and huge energy bill will be paid for by customers. When you consider how quickly energy costs are rising what will be the impact on customers’ bills?
Customers will also have to pay to build and operate alternative energy generation capacity so that Southern Water can meet the commitment it has already made for net zero carbon in operation by 2030. Would it not be better to select a more sustainable, less energy and carbon hungry process in the first place?
Southern Water are allowed to make profits from building infrastructure such as treatment plants, pipelines and pumping stations, so perhaps it is not surprising that they are selecting the option that requires the most infrastructure, rather than seriously considering a number of smaller, potentially cheaper, more environmentally friendly solutions which have less potential to deliver a profit. The lesson from putting all of their eggs in one environmentally unfriendly large infrastructure solution (desalination) has not been learnt.
It will have a very high environmental and carbon impact during construction & operation, the planet will pay the cost
Consider all of the materials needed for construction of the treatment plant, pipelines and multiple pumping stations required. Think about all of the energy that will be needed not only during construction, but to operate the pipelines pumping at least 3 Olympic size swimming pools of water 40km every day, even when the water is not needed. The carbon impact will be huge.
Then consider the environmental impacts;
During construction on the pipeline routes, especially for the 40km pipeline to Otterbourne. What will be the impact on biodiversity and local communities be?
- Of discharging recycled effluent into the reservoir every day.
- Downstream of the reservoir on the streams and Langstone Harbour.
The daily discharge of recycled effluent into Havant Thicket Reservoir will have adverse impacts on the reservoir wetland and biodiversity
Southern Water propose to pump in a minimum of 7.5 million litres of recycled water every day of the year to keep the reservoir topped up all the time. The original spring fed reservoir proposal was to create seasonally fluctuating water levels to maximise the benefit to biodiversity, by exposing islands for breeding birds in the summer, and muddy margins for young birds and migrating birds to feed on. A reservoir kept full does not provide the same benefits and as a result the biodiversity net gain that was promised when the reservoir received planning permission will not be delivered.
The water quality and wider environmental impacts have not been modelled and assessed. In fact, despite pressing ahead with the plans Southern Water will not complete these assessments until later in 2023. There is a concern that the proposal to discharge recycled effluent into the reservoir will increase the risk of algal blooms, eutrophication (especially in dead spots), cause temperature changes, plus there is a risk of accumulation of compounds in sediment and remobilisation.
The potential to create a unique and very special habitat will be lost. The reservoir was to have been filled with cool, naturally filtered chalk spring water. This provided the opportunity to create a unique and very special habitat which will be lost if effluent recycling is permitted. Most reservoirs are filled with river water with a significant silt and pollution load, especially from agricultural run-off, creating a high risk of eutrophication and algal blooms. Water quality modelling by Portsmouth Water had shown that the original spring fed reservoir would not suffer from these problems, with the chalk spring water expected to provide an oasis for biodiversity.
Budds Farm Sewage Treatment Works suffers from saline intrusion because of its location on the coast. While the treatment process planned will remove some of the salt it will not remove it all. As a result, any recycled effluent from this works would not be permitted to be discharged into a river. If the quality of the recycled water is not good enough to discharge into a river with a constant flow, then it cannot be acceptable to discharge it into the reservoir where there is minimum flow and more potential for accumulation, especially in the sediments or dead spots. What impact will this have on the freshwater reservoir and its biodiversity potential?
Increased pollution risk due to the lack of control of discharges in the Budds Farm Sewage Works catchment, along with the risk of inadequate treatment by Southern Water.
What will be the additional impact when they pump in up to 60 million litres per day (24 Olympic size pools) of recycled effluent into the reservoir each day, as proposed?
There has been inadequate environmental impact assessment and the very high-level screening undertaken to date has not been robust. Southern Water has confirmed they are not planning to undertake and publish even a Preliminary Environmental Information Report until later in 2023, yet they are ploughing ahead. Why don’t they wait until they understand the risks to the environment before selecting this option?
The impacts on Langstone Harbour have not been fully assessed
There are two ways that the effluent proposal can have an adverse impact on Langstone Harbour a European Protected Habitat (Special Area of Conservation and a Special Protection Area)
Water containing recycled effluent will be discharged from the reservoir to maintain the flow in the Riders Lane Stream and Hermitage Stream, which flow on downstream into Langstone Harbour.
The reservoir was to have provided a benefit to the harbour when spring water which would have flowed into Langstone Harbour was pumped up to the reservoir for use as drinking water, reducing the amount of nitrates entering the harbour which contribute to algal blooms. Nitrates present would naturally breakdown in the reservoir before flowing down to the harbour. This benefit to the harbour will be significantly reduced under Southern Water’s plan as less spring water will need to be pumped up to the reservoir, as the reservoir will be kept full throughout the year by the daily input of recycled effluent.
The modelling and screening assessment undertaken to date has not considered all the potential impacts on our coastal habitats. For example, it did not take into account the in-combination impact of changes to the reservoir operating regime, with less spring water being pumped up to the reservoir. The impact of emergency reservoir drawdown operation and testing also needs to be re-considered.
In addition, the effluent recycling process produces a toxic brine which will have to be discharged via the existing long sea outfall into the Solent.
The impacts of all these things on our protected coastal habitats need to be considered urgently as part of a comprehensive Habitats Regulation Assessment (HRA) before the scheme proceeds. However, Southern Water have indicated that the detailed HRA will not be completed until a planning application is submitted to the Secretary of State, by then it will be too late as they will argue there is no longer time to investigate alternatives. More environmentally friendly alternatives should be considered now.
There will be no application to the Local Planning Authority for permission for effluent recycling, despite assurances given at the time of the reservoir planning application.
Southern Water has already announced that they will not apply to the local Council for planning permission for effluent recycling via Havant Thicket Reservoir, instead they will apply for a Development Consent Order from the Secretary of State. This makes it even more important that local people have their say now while they have the chance.
This takes control away not only from the residents but also from the local authorities. The local Council will be given the opportunity to prepare a Local Impacts Report, but it is the Secretary of State who will make the decision. The process will be similar to that used for Aquind.
Southern Water have to demonstrate that they have consulted local people and stakeholders and this consultation is that opportunity. If the proposal for effluent recycling via Havant Thicket Reservoir makes it in to the final Regional Plan and the final Water Resources Management Plan being prepared by Southern Water it will be extremely difficult to stop the plans from going ahead. This is why it is so important that if you have concerns you respond to the consultation, and especially to send your concerns to Defra NOW. Defra have the power to challenge the Southern Water plans and ask them to reconsider aspects of the proposed plan.