Nirajan Dhakal

PhD fellow

Biography

Nirajan Dhakal from Nepal has a university degree in Civil Engineering(2002) and two master degrees in  water Supply Engineering (2011) from UNESCO IHE, The Netherlands and in Regional Development Planning and Management from TU Dortmund, Germany and University of the Philippines, Manila(2009).

After graduation in 2002 Nirajan worked for local government as Civil Engineer for the project funded by the United Nations Capital Development Fund (UNCDF) and British Governments Department for International Development (DFID) for 3 years. During this period Nirajan was active on providing the technical support on survey, design, implementation of the rural micro infrastructure such as water and sanitation, irrigation canal, micro-hydro, rural road, rural electrification. In addition, he also supported on the district level and community level participatory project planning process by guiding them through identifying and analyzing the issues, problems, needs and constraints. After this he joined humanitarian organization "Action Contre La Faim as Water and sanitation supervisor from August 2006 to May 2007. During this period he carried out pre-feasibility study and performed analysis to identify constraints and opportunities for the implementation of WASH project in Bajhang district (Far western region, Nepal).

In the last 2 years, he has worked as a researcher in UNESCO IHE for various research projects in membrane fouling and scaling in reverse osmosis system and vacuum membrane distillation in both laboratory and full scale pilot plant. He also involved on research project on seawater pre-treatment, organic matter characterization etc..

Currently he is a full time PhD student at Environmental Engineering and Water Technology Department at UNESCO IHE. The title of his research is "New generation of pre-treatments to eliminate organic and biological fouling in SWRO systems". The research project is funded by Wetsus, centre of excellence for sustainable water technology.

Topic

Algal Blooms and Seawater Desalination Systems: advanced pre-treatment to combat biofouling

Publications

Dhakal, N., Salinas Rodriguez, S. G., Schippers, J. C., & Kennedy, M. D. (2014). Induction time measurements in two brackish water reverse osmosis plants for calcium carbonate precipitation. Desalination and Water Treatment, 1-9. doi: http://dx.doi.org/10.1080/19443994.2014.903870

Dhakal, N., Salinas Rodriguez, S. G., Schippers, J.C., & Kennedy, M. D. (2014). Perspectives and challenges for desalination in developing countries. IDA Journal of Desalination and Water Reuse. http://dx.doi.org/10.1179/2051645214Y.0000000015

Shirleyana, Dhakal N., Arevalo M.(2012). Using GIS tools for identifying new family planning clinics, based on social and accessibility factors: The case of central java, Indonesia. Jurnal Ilmiah Ilmu Komputer UPH (Computer Science Journal of Pelita Harapan University) Vol. 9 No. 1 September 2012 ISSN 1412- 9523

RESEARCH SUMMARY

Reverse osmosis(RO) is finding new outlets as an alternative source in supplying water to meet the global demand of clean water. However, the operation of RO plants have been increasingly affected mostly by organic and biological fouling. Organic fouling often occurs when sticky microbial-derived biopolymers (e.g., transparent exopolymer particles) are abundant in the RO feed water. Furthermore, it may further initiate or enhance biological fouling as they can serve as a “conditioning layer” which is an ideal attachment sites for bacteria – a platform where bacteria can utilize effectively biodegradable nutrients (C, P, N) from the feed water while excreting more extracellular substances, resulting in rapid build-up of biofilm. Despite the availability of existing pre-treatment systems the issue of bio fouling still unsolved in RO systems. Therefore, the goal of the project is to investigate the application of low molecular weight cutoff ultra filtration membrane alone or in combination with ferritin as pretreatment options for seawater RO systems. The hypothesis of the research is that low molecular weight cutoff ultra filtration membrane rejects all the biopolymer concentration and ferritin will adsorb all the phosphate  that could eliminate or slow down biological fouling in seawater RO systems even during algal bloom situations. 

Funding source: Wetsus, centre of excellence for sustainable water technology