Innovative Cleaning Technologies for Production of Drinking Water during Flooding Episodes (A-WATER)

Project summary

Clean freshwater is a resource indispensable to all life and it is needed in large quantities for almost any human activity. Climate, freshwater, biophysical and socio-economic systems are interconnected in complex ways, so a change in one of these systems induces a change in another. Many studies have shown that climate change induces freshwater pollution and also, that it will cause increases in salinity when sea levels rise. Hence, activities to stimulate protection of water resources, sustainable use of freshwaters including water re-use are very urgent. In addition to regulative measures to facilitate sustainable water use, research on adaptive technology, energy optimization in water treatment systems, water recycling and reuse of water are important aspects of future water handling and management. The paradox during natural flooding disasters is that although a large area is flooded and covered by water, there is no clean water available. During such periods many diseases are likely to develop as diarrhea, typhoid, and skin problems due to lack of clean water. In Vietnam, many areas still do not have regular water supply systems but obtain drinking water from local wells. In other cases communities have water supply systems, but these systems are disabled or destroyed during flooding disasters. Unfortunately, it takes long time to re-launch these systems after a flooding, and it also has substantially costs. Hence, the current solution to temporarily produce water for drinking and cooking during a flooding disaster is to add alum for coagulation and precipitation of pollutans followed by disinfection by chloroamine. This is expensive, and the waters produced are not healthy and may contain pollutants even after treatment. Thus, producing and supply with freshwater during flood and post-flood periods are of special importance.

Outputs

Project Completion Report:
The obtained results in this project contributed the prediction and assessment tool that supports the decision of Vietnamese authorities in flood control. The environmental and health sector in Vietnam is highly interested in the flood water quality database and the effects of flooding on the mobilization of pollutants. The database is also useful in many different situations, including risk assessment. The construction of a flood water treatment addition, there would be a substantial benefit for public health when the technology has been implemented. The fundamental results also contributes to a better understanding and using of AOP as well as the reactivity of radical toxic organic compounds.

Three Vietnamese PhD students were educated following the “sandwich” approach with joint Vietnamese-Danish supervisors through scientific topics of the project. Each PhD student spent 9 months in Denmark. One PhD. student, one Danish and two Vietnamese MSc. students defensed their theses in related projects.

Some material, equipment and new instruments for this project have reinforced the capacity to perform fundamental and applied research by the Institute. These instruments are seen as part of the necessary infrastructure for development of the research unit on the adaptation technologies for climate change.Flood water quality database: the concentrations of 277 organic micro-pollutants and ten
elements (As, Cu, Cd, Cr, Co, Pb, Zn, Fe, Mn, Al) ranged from 0.01 to 7.6 μg L−1 and 0.1 to 3170 μg L−1, respectively, in the floodwater. Contaminants originated from industrial sources (e.g. PAH) were detected at low concentrations, ranged from 0.01 to 0.18 μg L−1, while concentrations of pollutants originated from domestic sources (e.g. sterols, pharmaceuticals and personal care products and pesticides) were ranged from 0.01 to 2.12 μg L−1.The results indicated that contaminants in floodwater come from untreated wastewater from villages, and the agricultural activities are the major sources of increased pesticides resuspended in the floodwater.

The flood water treatment pilot was built to produce 1000 L clean water/24 hours. It was built as a mobile and transportable system. An assessment on the validity of the method, technical parameters and economic factors were used for construction the prototype. The built pilot plan was applied for on-site drinking water production during flooding periods and for treatment of effluents from agricultural or aquacultural activities. The watercleaning pilot was tested in the field.