This document evaluates the removal and regeneration of MIEX® resin from coagulation sludge in water treatment. It details experiments using MIEX® resin and alum coagulation to remove natural organic matter (NOM) from synthetic feed water. The resin was regenerated using NaCl solution at different stirring speeds. Results showed 80-90% NOM removal when the velocity gradient during coagulation was between 770-980s-1. Mathematical models of NOM removal at different reuse cycles were developed but require further validation. The research demonstrated resin reusability but noted further work is needed to optimize regeneration conditions and develop models for industrial application.

1. EVALUATION OF MIEX® RESIN REMOVAL AND REGENERATION FROM COAGULATION SLUDGE
Ankur Ghosh, MSc Environmental Engineering
Introduction & Objectives
•Potable water is scarce at source and is being wasted, therefore
water treatment is very important to sustain and recycle the available
sources.
•This project deals with the first two steps of water treatment.
• Pretreatment involves Aeration followed by Low Dose
Ozonation or Chlorination, Ion Exchange or Activated
Carbon Adsorption.
• Coagulation and Flocculation deals with addition of
chemical coagulants which separate out the dissolved
impurities at a certain pH.
•Magnetic Ion Exchange (MIEX®) resin, developed by Orica
Watercare uses the principals of ion-exchange for removing DOC.
The magnetic component of iron oxide incorporated into the
polymeric structure (Boyer and Singer, 2008) facilitates rapid
agglomeration and settling.
•Chemical coagulation and softening, aid in removing suspended
solids from the water and aid in removing DOC. Chemical
coagulation in water treatment usually employs aluminum- or iron-
based salts, which precipitate as metal hydroxides. (Westerhoff et al.,
2005)
Al3+ + H2O → AlOH2+ + H+
Al3+ + 2H2O → Al(OH2)+ + 2H+
7Al3+ + 17H2O → Al7(OH)17
4+ + 17H+
.
.
.
Al3+ + H2O →Al(OH)3 + H+
•The objectives of this project are:
• To find suitable conditions for treating synthetic feed water.
• To establish effective separation of the resin from the
increased sludge quantity for regeneration followed by
reuse of the resin..
• To find the relationship between the regeneration speeds
and the efficiency of the resin.
Experimental Procedure
•The American Water Works Association (AWWA) have provided
with a calibration curve of the Gator Jar.
•Preliminary tests results show the best suited feed water, for further
experimental work was FW1 (Humic Acid = 25 mg.l-1, NPDOC=
5.296 mg.l-1) and the appropriate Alum dose was 22.5 mg.l-1.
•In the 2 litre Gator Jar, following the feed solution Alum and MIEX®
resin (10 ml.l-1) are added and the solution is stirred at 210 rpm for
1 minute and 50 rpm for the next 29 minutes for flocculation,
followed by 30 minutes for settling. Placing a magnetic slab beneath
the jar ensures the MIEX® resin separates as quickly as possible.
•The supernatant is decanted off after collecting a sample of 75 ml.
The thickened sludge zone and the MIEX® resin remain.
•The regeneration step: addition of 10 ml of NaCl solution (58.5
mg.l-1) for 20 ml of MIEX® resin in the sludge. The slurry is stirred at
a high speed of 130 rpm, 210 rpm, 260rpm, and 330 rpm. A
particular speed is maintained for every set of experiments.
•The brine has to be rinsed off resin by distilled water.
•Following this, another coagulation procedure is implemented
using the regenerated MIEX® resin.
•Due to reduced sludge volume, the governing equation of the
velocity gradient, G= √(P/µV) is altered to give a new relation
between the old and new velocity gradients, Gnew = 2G
Results
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0 2 4 6 8 10 12
UVAbsorbance
MIEX® Resin Use/Reuse
G=380
G=480
G=770
G=980
G=1400
Poly.
(G=380)
Poly.
(G=480)
Poly.
(G=770)
Poly.
(G=980)
Poly.
(G=1400)
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12
NPDOCRemoval%
MIEX Resin Use/Reuse
G=380
G= 480
G=770
G=980
G=1400
Substantial removal of NPDOC (80-90%) is due to an applied velocity
gradient in the range 770-980s-1
Introduction to Mathermatical Model
At G=770s-1, y = -2.5147x2 + 29.192x
At G=980s-1, y = -3.0069x2 + 34.936x
y= NPDOC removal percentage; x= number of resin
regenerations and reuse cycles
Conclusion & Future Recommendations
•The combined use of MIEX® resin and coagulation is a
innovative step forward from a technical point of view.
• Biggest advantages of this resin is its reusability.
•This research shows that the resin can perform
exceptionally well when regenerated under a certain
range of conditions.
•Due to time constraints, the different conditions could
not be experimented upon which can be researched in
the future.
•There is no exact mathematical model which shows
how this process can be employed industrially. Neither is
there any mathematical model on the ion-exchange
characteristics of the resin. The attempt to derive the
mathematical model creates many areas for further
research and validation such as the frequency of
regeneration and the resin’s performance if it is not
regenerated each time.
Acknowledgement: Prof. Nigel Graham, Mr. Tom Williams, Dr. Geoff Fowler, Mrs. Carol Edwards, Mr. Fuwang Zhao and my friends and classmates
References
•Boyer, Treavor H. & Singer, Philip C. (2005) Bench-scale testing of a
magnetic ion exchange resin for removal of disinfection by-product
precursors. Water Research, 39 (7), 1265-1276.
•Westerhoff, Paul, Yoon, Yeomin, Snyder, Shane & Wert, Eric. (2005)
Fate of Endocrine-Disruptor, Pharmaceutical, and Personal Care
Product Chemicals during Simulated Drinking Water Treatment
Processes Environmental Science & Technology 39 (17), 6649-6663
•Michael J., Semmens P.E., Burckhardt, M. , Schuler, D. , Davich, P. ,
Slunjski, M. , Bourke, M. and Nguyen, H. (2000) An Evaluation of
Magnetic Ion Exchange (MIEX®) for NOM Removal. Proc. of AWWA
Annual Conf. Denver, CO.
•Slunjski, M., Cadee, K., Tattersall, J. ( 2000) MIEX® Resin Water
Treatment Process, in AquaTech; Amsterdam.