With the right technology wastewater recycling can be both cost effective and regenerate ultra-pure water that can be returned to the groundwater or used in agriculture and industry. This has been shown by a research project carried out by IVL Swedish Environmental Research Institute and Xylem, a provider of fluid technology solutions.
The project has established that it is feasible to reuse wastewater in a wide range of applications — without increased negative impact on either the environment or current treatment plant running costs, says Christian Baresel, project manager at IVL Swedish Environmental Research Institute.
The strategy of reusing treated wastewater as a natural part of water resource management is relatively new, and is still regarded by many countries, including Sweden, as a solution that is some way off in the future. Therefore, there are almost no general rules or expertise available regarding the water quality required for various reuse purposes. There is also a lack of information and knowhow about the purification techniques that can be utilized and methods to achieve resource and cost-effective treatment with minimal environmental impact.
These various challenges have been identified and studied in the collaborative project ReUse, carried out by IVL Swedish Environmental Research Institute and Xylem. The project has defined water quality criteria for three different purposes; reuse in agriculture, re-use in industry and for reinjection into the groundwater. The criteria are based on a number of specific standards and regulations drawn from a number of different regions across the world that currently practice water reuse.
Since then the project has developed two different treatment systems based on water treatment technologies already available today; activated sludge treatment in so-called SBR plants (batch biological treatment) micro and ultra filtration, ozonation, sand filters, trickling filters, activated carbon and UV. The systems have been evaluated and optimized in pilot scale at the joint IVL and KTH research facility Hammarby Sjöstadsverk in Stockholm and in cooperation with a number of full-scale plants around the globe. A detailed environmental impact analysis, Life Cycle Assessment (LCA) and a cost assessment of the life cycle (Life Cycle Costs, LCC) has been made for the purification systems based on the results in the pilot tests and full-scale plants.
These findings show that with the help of the tested treatment system it is possible to meet the defined water quality criteria for the targeted uses. The total environmental impact of the treatment systems is not expected to be higher than today’s traditional treatment systems. The cost of the various treatment systems is lower than costs recorded for current conventional treatment plants in Sweden.
– Recycling of wastewater will enable us to meet water supply challenges in the community. With reduced groundwater levels, increased costs of clean fresh water, increased competition with other sectors such as agriculture and industry but also water shortages due to environmental degradation, the reuse of treated wastewater has never been more important than now — regardless of whether the beneficiary is agriculture, industry or the environment says Christian Baresel.