Muhammad Nasir Mangal

PhD fellow

Biography

Nasir Mangal holds a BSc degree in Civil Engineering from Kabul University, Afghanistan. After completing his undergraduate studies, he worked for three years as a Project Manager and Civil Engineer in US Army Corps of Engineers (USACE) and Asian Development Bank (ADB) projects based in Afghanistan. He was awarded the Rotary International scholarship to pursue his graduate studies in The Netherlands. He completed his master’s degree in Urban Water and Sanitation with specialization in Water Supply Engineering in 2016 at IHE- Delft. From August 2016, he started his PhD studies at IHE- Delft and University of Twente. 

Topic

Controlling calcium carbonate scaling in groundwater reverse osmosis systems

Research Summary

Maximizing recovery in reverse osmosis (RO) applications is essential, as at maximum recovery, the production of brine and also the specific energy consumption (kWh/m3) are minimum. However, when treating brackish water, the main obstacle to achieve high recoveries (80 - 90 %) is membrane scaling. Scaling is caused by the precipitation of sparingly soluble salts (e.g., calcium carbonate, calcium sulphate, barium sulphate, etc.) on the membrane surface and feed spacer. Among various species of scaling, CaCO3 is the most common in RO systems. To obtain high recoveries without the risk of scaling, antiscalants are dosed to the feed water.

It is important to optimize the antiscalant dose in RO, since, low doses may not be sufficient to control scaling, while high doses have environmental concerns, results in high costs, and also can lead to other types of scaling/fouling. Antiscalant dose for a given water composition is generally determined using the proprietary programs of the antiscalant suppliers. However, the method employed by the antiscalant suppliers is not known and therefore the end users/consultants cannot verify the doses calculated by the projection programs. So far, induction time measurements are used for CaCO3 scaling studies. However, until now, it is not fully studied if the induction time measurements in glass reactors can be used as an indicator of scaling in RO applications. Therefore, to estimate the antiscalant dose for a given feed water composition, no standard scaling test is available.

The aim of this research is to develop a method to efficiently determine the optimum antiscalant dose at maximum recoveries to prevent calcium carbonate scaling in brackish water RO systems.The PhD research is conducted in collaboration with Oasen Drinking Water Company (based in Netherlands) and Grundfos (based in Denmark).

Publications

Journal paper:

  • Abushaban, A., Mangal, M. N., Salinas-Rodriguez, S. G., Nnebuo, C., Mondal, S., Goueli, S. A., . . . Kennedy, M. D. (2017). Direct measurement of ATP in seawater and application of ATP to monitor bacterial growth potential in SWRO pre-treatment systems. Desalination and Water Treatment, 99, 91-101. doi: 10.5004/dwt.2017.21783

Conference paper:

  • Mondal, S., Abushaban, A., Salinas Rodriguez, S. G., Mangal, M. N., Goueli, S. A. & Kennedy, M. D. (2017). Development and application of new methods to measure bacterial activity and nutrients in seawater reverse osmosis (SWRO) In: AMTA/AWWA (ed.) Membrane Technology Conference & Exhibition. Long Beach, CA, USA.

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