Safer cheaper cleaner water

Abstract: The applicants have recently developed a low cost water disinfection device for use in the developing world. The device is extremely simple in design, comprising two interconnecting PVC pipes through which copper beads are driven by means of a hand or bicycle propelled impeller. When water is introduced into the pipes, the impeller brings the copper beads into repeated contact with any microbial pathogens that may be present effecting their 99.8% destruction within 10 minutes. The device was designed for use in densely populated shanty towns and peri-urban environments which cannot afford to construct underground sewage networks. In these communities, faecal sludge from pit latrines is commonly processed in local, interim treatment facilities staffed by 2 or 3 workers. These individuals need a safe and simple means of sterilizing the extremely dangerous, bacteria-rich water which must be squeezed from faecal sludge before the dewatered sludge can be transported to a municipal sewage facility.
In this project, the applicants intend to scale up this device and establish that is a more cost-effective and sustainable means of disinfecting water than Ultra Violet (UV) light. UV light disinfection systems are widely used in waste water treatment plants throughout the world. UV light has a number of benefits compared to chemical disinfection methods, principally that it obviates the need for the transportation, storage and handling of caustic chemical agents. However, it is still a sub-optimal technology in that it suffers from four key disadvantages: (a) the substantial overhead, operating and maintenance costs of UV equipment; (b) the efficiency of UV drops significantly if the water is either turbid or contains heavy solids; (c) UV does not fully inactivate certain viruses, spores and cysts and (d) very high throughput is difficult because UV cannot effectively penetrate pipes above a certain diameter.
Having already met the challenging cost targets in an application for the developing world, the applicants are confident that this technology can be rapidly scaled up and rolled out across the developed world. In this regard, the key point to grasp is that UV systems require electrical energy both to pump waste water and to destroy the pathogens within it; the same is true for recently developed systems employing electrolytic cells and oxidants such as hypochlorous acid. In the case of the applicants' technology, however, no electrical energy is required to destroy the pathogens at all - the water merely needs to contain sufficient oxygen to allow the copper to create metal ions.
In Phase I, the project will focus on demonstrating that waste water from a Northumbrian Water sewage treatment works can be processed by the device to a standard that will allow it to be discharged into designated shellfish or bathing waters. In Phase II, the applicants will construct a continuous flow, pilot-scale version of the device (10,000 litres per day) which will generate robust process economics demonstrating that the technology produces safer, cheaper, cleaner water at much lower costs than those which can be attained using conventional UV disinfection.