August 1, 2017
Much progress has been made in educating the public about what can be thrown into sewers. Now legislation is required for a control-at-source approach
The safe collection, treatment and return of waste water is vital for our economy and society. Add to this the fact that waste water is a rich source of energy, vital nutrients and fertilisers, and that treated waste water can be reused, and we have a resource that can make significant contributions to maintaining water for future generations and to meeting key environmental and economic goals.
EurEau’s Committee on Waste Water examines how we treat and can use waste water in Europe. The committee is supported by three working groups and their chairs: Waste Water Resources (Arne Haarr, Norsk Vann, Norway), Trade Effluents (Michael Bentvelsen, Unie van Waterschappen, The Netherlands); and Compliance (Sarah Gillman, Scottish Water, UK).
In all, the committee has over 50 members with an interest in protecting public health and the aquatic environment in a sustainable way, for example, by promoting energy savings, nutrients recycling and the reuse of treated water.
The committee’s main topics for this term are: addressing the issues of micropollutants by promoting source control as often as possible; enhancing resource efficiency and nutrient recycling in the waste water sector as part of the circular economy; building resilience to climate change; protecting the environment through better management of urban waters; and proactively addressing the revision of the Water Framework Directive (WFD) (foreseen for 2019).
The principle piece of EU legislation governing our work is the Urban Waste Water Treatment Directive (UWWTD), adopted in 1991. Its main objective was to legislate for the collection and treatment of urban waste water leading to sustainable environmental protection from urban domestic and industrial pollution. It achieved this in part by combating the accumulation of nutrients in sensitive water systems, as these support the growth of algae, depleting the shallow waters of oxygen and therefore aquatic life. The WFD implementation largely benefits from this work.
Brown gold and the circular economy
The European Commission’s Circular Economy Package (CEP) will help all of us use and recycle resources in a more sustainable way. This will be achieved by extracting the maximum value and use from raw materials, products and waste, while promoting energy savings.
Waste water is a source of secondary raw materials. We support the revision of the Fertilisers Regulation that opens the door to an EU-wide market for recovered nutrients and hopefully for high-controlled bioproducts from sewage sludge like composts and ashes.
Our members already recover nutrients from waste water that can be used directly in agriculture in certain Member States or through extraction processes if the direct use of biosolids in agriculture is not authorised. We advocate that all solutions should be available to increase the recovery of the good materials from sewage sludge.
Water, water everywhere…
Water is too precious to be used once. It is crucial that water is managed so that everyone can benefit from it. Water reuse is the use of treated waste water. It is one way to increase the available water resources, mitigating water scarcity. Water reuse has environmental, social and economic gains.
The CEP proposed addressing water scarcity through the reuse of treated waste water in safe and cost-effective conditions. It is a major step to maintaining water resources for all. It is a tool to support water reuse projects and raise the image of reclaimed water towards the end users by ensuring its quality and safety. Reused water is safe.
Europe needs to establish common, minimum-quality standards according to the foreseen use of treated waste water that protects health and the environment. We, the water operators, are working with European institutions and Member States to bring in water reuse legislation. Our members have the experience and technology to achieve ambitious EU-wide quality standards set for the safe reuse of treated waste water.
Waste water collecting systems and the effects of heavy rain
System performance should no longer be measured only in terms of compliance with discharge standards for waste water treatment plants but should also consider the performance of the collecting system, now often the weak link in the system.
Ageing sewers require extensive renovation investment, rehabilitation, replacement and upgrades to reduce waste water loss or infiltration of groundwater. The impact of these projects on urban mobility has seen the emergence of ‘trenchless’ techniques, thus opening economic opportunities.
The consequences of climate change vary across regions and require adapting infrastructure, especially where the storm water drainage systems face intense rainfall events.
The waste water collecting systems are often combined (i.e. sewage and rainwater are mixed in the same pipe) and are then designed with ‘safety valves’ to avoid overloading and urban flooding. On some occasions, these combined sewer overflows can result in waste water being released into the natural environment during heavy rain. The waste water is certainly diluted by large amounts of rainwater but the actual contents of polluted waste water remains relatively unknown. These overflows are regularly held responsible for the failure to achieve environmental quality objectives.
The solution – an overall but site specific integrated management of storm water and waste water in the urban cycle – involves many stakeholders other than water operators, for example, spatial planners and local decision-makers who need to integrate the management of runoff from the initial designs of their urban development projects.
More than pee and poo: our waste
There is no life possible without the production of waste. The residue of our lives, themselves reflections of our consumption, end up in our treatment plants.
Many products such as organic waste, paper, wet wipes, detergents, cosmetics and personal hygiene products, scouring agents, descaling agents, disinfectants, microfibres and pharmaceutical residues, to mention a few, are found in waste water. The compliance to the UWWTD that drove the design of our waste water treatment plants (WWTPs) did not include all these pollutants.
Treating contaminants is costly and upgrading our WWTPs will impact bills. The source-control approach which avoids contaminants ending up in sewers would be the most efficient. With European institutions, we need to educate the public on what can or can’t be thrown into sewers. We also need to develop legislative instruments to make the control-at-source approach for pollutants a reality, to integrate biodegradation tests when making and marketing products and to inform the consumer on the proper disposal route.
In 25 years, the UWWTD has changed the way we look at the impact of our individual and collective behaviour. Many challenges lie ahead. We strive to anticipate and meet these challenges each day. Safeguarding our water is everybody’s business, from political leaders to water consumers, through academia, research centres, engineering firms, network operators and many others.
It will be for the EU to channel and encourage these developments in a rigorous but flexible legal framework, respectful of the different actors and their investment capacity, to continue to improve these aquatic environments.
By Greet De Gueldre and Jean-Pierre Silan, co-Chairs of the EurEau Committee on Waste Water
Read more in Water MattersAuthor : EurEau