Getting all the value from waste water Removing pollutants is of course a priority at waste water treatment plants, yet there is a growing awareness that they could also act as production units, providing energy, nutrients and other valuable resources. Uwe Fortkamp and Klara Westling tell us about the R3 Water project’s work in developing innovative technologies to support the development of waste water treatment plants The core function
of a waste water treatment plant is to remove emissions and pollutants from waste water, yet they could potentially play a broader role, including in nutrient recovery, energy production and water re-use. Based at the Swedish Environmental Research Institute, Uwe Fortkamp is the Principal Investigator of the R3 Water project, an EC-backed initiative developing innovative solutions to support the development of waste water treatment plants. “We want to support the transition from being purely a treatment plant towards a production facility,” he explains. The aim is for plants not to focus solely on treating water and meeting quality thresholds, but also to develop usable products, covering three main areas. “One is re-using water. We are treating water, so why not re-use it?” points out Fortkamp. “The second is to recover valuables, we have looked at sludge treatment and phosphorous recovery. The third is resource efficiency – there is a strong focus on energy issues in the project, on using the incoming energy with the water in a positive way as well as being resource efficient and saving energy in each treatment step.” WWTP Antwerp-Zuid
Re-using water This research centres around modifying and upgrading existing waste water treatment plants with new solutions rather than creating an entirely new process. One aspect of this work is developing technologies to disinfect and monitor water for reclamation; while some treatment plants already do this, Klara Westling, project manager at IVL Swedish Environmental Research Institute says there is still scope for improvement. “With the technologies that we are
“This sludge is a cost factor for the plant. What we’re asking is – can we do something more with it? Can we produce value out of it?” continues Fortkamp. “Phosphorus is one target, and we are also looking at using a process called Hydrothermal Carbonization (HTC), which allows us to produce a biochar. This biochar could then be used for other purposes as well – for example, depending on how you operate the process and how the parameters are set, you might get a type of activated carbon.”
Increasing the ratio of water reuse is one of the key priorities for the EC in the upcoming years. In this context, the online monitoring of microorganisms can provide important benefits, including efficient production of
reclaimed water
developing, we aim to ensure that the water system is much safer than it is today. At the moment, the drinking water supply can still get contaminated,” she stresses. Researchers are developing several different technologies, including an advanced online monitor for levels of micro-biological infectious pollutants in water. “These technologies are designed to monitor water quality, which is particularly important if you want to re-use it – a typical way of re-using water is in agriculture, for irrigation,” continues Klara.
A number of countries prohibit the re-use of sludge in agriculture however, in which case it is often incinerated. Nutrients can again be recovered following this process. “When sludge is incinerated, ashes are produced, and it is possible to recover valuable nutrients from these ashes. The first target is to look for phosphorous, which would otherwise be lost if the ashes were put into landfill,” explains Fortkamp. Depuradora d’Empuriabrava.
Nutrient recovery A second major area of the project’s research relates to nutrient recovery. Sludge is a byproduct in the waste water treatment process, originating from both incoming particles as well as from microbiological sludge generated in the process; handling this sludge efficiently is an important issue for many waste water treatment plants.
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