A pilot plant based on the principle of gravity-driven membrane disinfection has been designed and built in 2008 in collaboration with Veolia, Kompetenzzentrum Wasser Berlin and Opalium,. The pilot plant was tested in France (Veolia Research Centre, Annet-sur-Marne (France)) and in South Africa (rural settlement Ogunjini, KwaZulu-Natal) in collaboration with Umgeni Water Works during the period of January 2009 – May 2010. This project was supported by the European Commission (project Techeau).
Placed in a 10 feet-long maritime container, the unit is composed of following componen
- A submerged flat-sheet UF module (membrane area: 40 m2).
- A storage tank for residual chlorination to avoid recontamination of treated water (not used in this study).
- Biological sand filtration was introduced into the system in order to decrease surface load of the membrane. In order to investigate the impact of biological sand filtration, it was in operation during tests in France and was by-passed in the later stages.
The pilot plant has a capacity of 4 m3/d .
Pilot plant based on biological sand filtration and GDM-filtration
The pilot plant was operated in a dead-end mode without back-flushing or cleaning. However, impact of manual drainage was studied and manual drainage was applied 1-7 times a week. In France, untreated water from river Marne, France was feeding the system. This water had turbidity of 3-258 NTU and TOC of 0.9-7.7 mg C/L. Flux values of 5-7 L/m2/h (20OC) were measured.
In South Africa, river water feeding the plant had turbidity of 10-600 NTU and TOC of 1.6-2.5 mgC/L. Flux values of 4-6 L/m2/h (at 20OC) were measured when turbidity of river water was lower than 160 NTU. However, rain events resulting in increase of turbidity of river water over 600 NTU over several days led to a reduction of flux and its stabilization at 2-3 L/m2/h (see Figure 12). It was concluded that a pre-treatment is required for the system when raw water turbidity exceeds 100 NTU.