Microbiologically safe drinking water by river bank filtration and one step membrane filtration
In drinking water production, river bank filtration (RBF) has a number of advantages, such as dampening peak concentrations and natural removal of micro-pollutants, suspended solids and pathogens. In the Netherlands, RBF is successfully implemented. This technique has a high potential for China. China is using the Yellow river, Chang river, Songhua Jiang river as source for drinking water. It is necessary to evaluate the feasibility of RBF in Chinese circumstances and determine if and what post-treatments are needed for RBF.
Reverse osmosis (RO) is a promising technique to produce drinking water, free of pathogens, toxic chemicals and micropollutants, and it is considered feasible to combine this with RBF without any further pre and/or post-treatment. RO has been widely studied in sea water desalination. The combination of RBF-RO is currently under investigation in the Netherlands. However, as there is no other step as barrier to safe guard the final water, it is necessary to evaluate the microbial risk over RBF and RO. In principle, the combination is an effective barrier against pathogens, but the design of a safe direct treatment does require knowledge about the presence, behaviour and health risk of pathogens in these treatment processes. Similarly, the combination may be an effective treatment to remove biodegradable compounds that could give rise to microbial growth in the distribution network, but this too requires knowledge about the relation between system design and characteristics and the removal of nutrients.
Objectives
The main goals of this study will be: 1) understand the mechanism of removal and persistence of pathogens, biodegradable compounds and organic micro-pollutants in RBF-RO systems; 2) develop design criteria for safe RBF-RO systems; 3) Evaluate the feasibility of RBF/RBF-RO in a selected area in China.
Study design
The research activities, bench-scale column studies and field work, will be conducted in both China and the Netherland, over three years. Knowledge obtained from the field and column study will be used to define site selection and design criteria to guide the start-up of RBF research in China. Sand column study for RBF simulation and combination with RO will be done afterwards in the third year.
Anticipated results
The following results are expected from the proposed joint research:
1) The mechanism of pathogen, biodegradable compound and micropollutant removal and persistence over treatment of RBF-RO will be understood, so as to guide the site selection and system design in China.
2) The feasibility of applying RBF/RBF-RO in China.
Scientific relevance
This proposed joint research will fill the knowledge gaps on the behaviour of transport of pathogens, biodegradable compounds and relevant micro-pollutants in soil and groundwater of RBF in combination with RO simultaneously, as a basis for appropriate site selection and design of safe RBF-RO water supply systems. Moreover, the feasibility of RBF-RO will be evaluated based on the understanding of the applied technique and its performance in different circumstances.
Collaboration
The section of sanitary engineering of TU Delft, works together with RCEES, a Chinese academy of science institute in Beijing. The collaboration consists of joint workshops and exchange of (PhD) students.
Funded by
NWO
Project coordinator
Gertjan Medema
Period
2014-2015