Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/1019735
September 2018 water.desalination+reuse use a distillation technology. "The point here in Colorado was to prove out that we can do reuse with a technology system that would not require disposal of a brine stream," says Green. The flow rate was 15 gallons (0.06 cubes) a minute going in and 8 gallons (0.03 cubes) a minute going out. "The flow volume was set by the available equipment, plus we needed to fill up that tanker truck," Green says. Wintertime demo The project was challenged by a super-fast timeline, less-than-opti- mal temperatures, and a require- ment to make the internal workings of the plant accessible to visitors. The tight timeline was driven by Denver Water, which wanted the produced water for making beer to drink at its centennial anniversary celebrations this year. The system therefore started up in January and ran through to end of April, mean- ing that it was executed quickly, and in sub-zero temperatures — with a knock-on effect for the biologi- cal processes. "The biology of the BAF does better at a stable, warm temperature, and so it was a chal- lenge to figure out how to get that filter inside the building because it's about 20 feet tall," says Green. "Typically, demonstrations are done in dry, arid places such as California or Arizona, during the summertime. As far as we know it was the first wintertime pilot of its kind." The site required clever con- struction, too. "There was a lot of piping going from one unit process to the next; and therefore a lot of custom construction of walkways and stairways to enable people to go inside the containers and see the technologies," Green says. Other challenges included tech- nical hiccups such as leaky gaskets, a stringent stormwater discharge permit, and freeze protection for external elements. The biggest challenge, though, was to secure the time of the politicians who the demo sought to influence. "These are people with very busy schedules, so getting them to free up the time to come and see it was tough," says Green. In the end, the project won attention from senior politicians and water leaders, including State Representative to Congress Jeni Arndt, legislative aides to Congress, Mayor of Denver Michael Hancock, American Water Works Association (AWWA) chief executive Dave LaFrance, senior state regulators, and host of leaders from state water utilities. Green concludes: "It wasn't just the demo, the tech and making the water, we had to get the political people in the state to come and look. The process was five months start to finish. They got a lot of peo- ple, they did a pretty good job." Build it, and they'll come The four-month-long PureWater Colorado wastewater reuse demonstration project in Colorado, US, filled a tanker with drinking water which was used to brew beer to celebrate the centenary of utility Denver Water. Water reuse treatment trains The two treatment trains currently considered as 'go-to' Inland: Ozone - BAF - MF - GAC - UV AOP By the ocean: Ozone - BAF - MF - RO - AOP N.b: Ozone contactor; biologically active carbon filter (BAF); microfiltration (MF) membrane; granular activated carbon (GAC); reverse osmosis (RO) membrane; ultraviolet (UV) advanced oxidation process (AOP). The team at PureWater Colorado aimed to demonstrate the potential of inland wastewater reuse projects, and to promote the debate about reuse among Colorado state politicians, utilities, and the general population. The project was hosted by utility Denver Water and was a collaboration led by Carollo Engineers which brought together expertise and technologies from Calgon, Carollo, Pall, and Xylem. The latest options in treatment for wastewater reuse