Out of a population of 16.5 million, the Netherlands boasts around 2,000 companies active in the field of water, employing some 80,000 people. The immense expertise present in the country and its rich history in water management give the Netherlands a strong foundation and a leading edge in helping with efforts pertaining to improving the access to, and quality of, clean water across the globe.

Eight innovative technologies from Delft University
At the recent international Leading Edge Conference on Water and Wastewater Technologies (LET2011), held in Amsterdam in June 2011, leading representatives from both academia and industry presented the latest developments in the field of water purification technologies. Leading Dutch university, Delft University of Technology (TU Delft) stole the show somewhat with its presentation of eight innovative technologies for water purification. These are detailed here below.

Capturing CO2 during waste water treatment
TU Delft has developed a method of capturing carbon dioxide (CO2) during wastewater treatment which provides a possible alternative to underground CO2 sequestration. In addition, the university is involved in projects carried out in Hong Kong that test the viability of using seawater for flushing toilets. This technology will not only facilitate phosphate recovery but generate a more efficient and integrated system for large-scale facilities such as airports.

Separate cellulose from toilet paper
The private company, Waternet, has partnered with TU Delft to embark on a project to test the effectiveness of treating wastewater in order to separate cellulose from toilet paper. Toilet paper in most regions of the world is discharged together with wastewater to a wastewater treatment plant (WWTP). Removing toilet paper by utilising sieves is technically possible and a number of large-scale applications are known, in combination with a methane bioreactor or as an alternative for pre-settlement tanks. Preliminary research performed by Waternet gives clear indication that no significant degradation in the sewer systems takes place. In addition to recovering raw materials, this innovation will optimise the entire wastewater-purification process.

Worms minimizing sewage sludge
In collaboration with TU Delft, SR Technologies has developed and expanded research investigating the use of worms to minimise sewage sludge. A field trial at the treatment plant Wetterskip Fryslan in Wolverhampton shows how worms not only break down the sludge, but also provide improved sludge fermentation. The combination of degradation and fermentation provides a robust and above-all sustainable process, which is suitable for addition to different types of treatment plants.

Phosphate removal with bio-nanotechnology
In the field of water purification technology, BiAqua, a TU Delft spin-off company, has developed a bio-nanotechnology process that selectively removes phosphates from water, thereby preventing microbial growth. This will do away with the necessary dosage of toxic chemicals, as the technology employs bio-based material, as opposed to chemical and other materials. Another such project, this time in collaboration with Oasen, involves the biological removal of iron and ammonium from drinking water.

Sewer mining with forward osmosis
KWR Watercycle Research Institute, Waternet, Triqua and HTI have, together with TU Delft, developed an innovative project to produce high quality water from sewage by combining wastewater treatment processes so as to optimise the energy recovery process. This is achieved by producing renewable energy from the organic content contained in sewage. The Sewer Mining concept is aimed at producing high quality water from sewage by means of Forward Osmosis (FO) in combination with a re-concentration system. The innovative Sewer Mining Concept enables high quality water production whilst reducing the energy consumed by current installations. This system could culminate in an economical, environmental and technological breakthrough.

Aerobe granular biomassa
On the last day of the conference, an excursion to the first Aerobe Korrelslib reactor in Epe was organised for participants. The reactor, developed by TU Delft and built by engineering consultants DHV, in collaboration with Dutch water boards, is being hailed as the water purification system of the future. This is because the purification system requires only 30 percent of the physical area taken up by the existing facility, which delivers savings in energy and costs of around 20-25 percent.

More information:
TU Delft
Section Sanitary engineering
+31 15 2783347
www.citg.tudelft.nl/en/