The water sector has entered a pivotal phase. The public is demanding, rightly, both significantly improved services and environmental protection, and now it’s time we deliver.
Mike Froom, Te-Tech Process Solutions explains.
The targets are set, some well beyond AMP8, with the aim to ensure the next five years are only just the beginning of an extensive programme which will last decades. But visible results will be expected by 2030, so the pressure is on.
The industry must reduce pollution, increase resilience, prepare for climate change, and put itself on a path to net zero. And with record levels of spending, £104 billion over the next five years, the sector has a great opportunity for transformation.
Environmental protection
The Water Industry National Environment Programme (WINEP) in AMP8 will focus on significant environmental improvements. Key objectives include reducing storm overflow discharges, enhancing river and bathing water quality, and achieving ambitious reductions in pollution incidents. The program aims for substantial investment in infrastructure and nature-based solutions to meet these targets and contribute to the UK’s environmental goals.
AMP8 includes £24 billion for improving the environment, covering upgrading over 1,700 wastewater treatment works to help reduce pollution, and £6 billion of upgrades to combat nutrient pollution. With longer-term government targets including reducing phosphorus loadings from treated wastewater by 80% by 2038 (against a 2020 baseline). So, what are the options regarding P-removal?
Strategies
Ferric salts are commonly used to precipitate out phosphorus from wastewater, but there are more sustainable options. Ferric creates several issues. It’s highly corrosive and wreaks havoc with tanks and pipes, and therefore must be neutralised, bringing its own set of problems. Chemical precipitation also significantly increases sludge volumes, which necessitates further treatment of the precipitates generated – adding unwanted additional costs to the process. Huge ferric price fluctuations, quality and supply chain reliability issues must also be considered.
Natural solutions like reed beds and wetlands can be designed to be attractive features but, they take up large areas because BOD loading is a limiting factor on how much raw domestic wastewater they can handle. Nature-based approaches, like constructed wetlands, are likely best implemented as “final effluent polishing” in a way that can add amenity value and promote biodiversity.
Enhanced biological phosphorus removal
The solution is to maximise biological phosphorus removal. Creating conditions that promote the growth of beneficial microorganisms that naturally consume phosphorus as a nutrient source. Biological methods can do the bulk of the work, therefore minimise chemical usage, and avoiding any increased sludge generation, and additional operational costs.
Advanced cyclic activated sludge technology, utilising biological P-removal, works using a single-stage batch setup, which allows for continuous flow and eliminates the need for buffer tanks upstream or downstream. This reduces the overall site footprint as well as removing the need for mechanical mixing, therefore reducing energy costs – offering efficiency and sustainability, with fewer chemicals.
The sludge technology satisfies multiple drivers at once, with simultaneous nitrification, denitrification, and biological P-removal in a single treatment stage. And provides a lower whole life cost when compared to a conventional SBR or activated sludge process. The cost savings are attributed to reduced infrastructure and space requirements. Without the need for primary treatment, anoxic or buffer tanks, the site footprint is reduced, removing additional land requirements. Moreover, chemical costs can be reduced due to less ferric and alkalinity dosing.
Small footprint, big impact
AMP8 and WINEP demands innovation. Compact, packaged advanced technology, which can be rapidly deployed can step up and deliver results for P-removal schemes. And the benefits of a low chemical, efficient technology can be amplified if used in coordination with nature-based solutions, like wetlands, which can provide a huge biodiversity boost.
