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					International Conference on Science, Technology and Innovation for Sustainable Well-Being
(STISWB), 23-24 July 2009, Mahasarakham University, Thailand

   Dissolved Ammonia Adsorption in Water
           Using Over Burnt Brick
                     Shukra Raj Paudel* and Dr Bhagwan Ratna Kansakar**
                      *Lecturer, Tribhuvan University, Institute of Engineering,
                           Pulchowk Campus, Pulchowk, Lalitpur, Nepal
                     **Professor, Tribhuvan University, Institute of Engineering,
                           Pulchowk Campus, Pulchowk, Lalitpur, Nepal


  The groundwater of Kathmandu Valley contains very high concentration of ammonia nitrogen which
is in excess of WHO guideline value for drinking water. This study mainly focuses on the removal of
ammonia nitrogen in water by adsorption in locally available over burnt brick. The study was carried
out in a 4.2 cm internal diameter column of 120 cm length packed with over burnt brick in up flow
 The study showed that the ammonia nitrogen removal rate increased with increase in contact time
which decreased with time until steady state condition is attained .The contact time varied from 4
hours to 9.5 hours for different particle sizes. The optimal value of adsorption rate constant was found
as 0.1097 for particle size of 0.850-0.600mm at corresponding contact time of 7 hours. The adsorption
data appears to fit the Freundlich’s isotherm. The fixed bed adsorption operation indicated that the
ammonia nitrogen is the function of service time, bed depth and flow. Linear regression model
showing correlation of these parameters has been developed.
Key Words: Kinetics, Contact time, Isotherms, Column study and linear regression.

1. Introduction                                       supplies have been reported in Mc Carty,
   Ammonia is a natural by-product of the             1967 [5].
decomposition of various types of organic             Groundwater quality of Kathmandu valley is
matter. The occurrence of free ammonia                degraded up to different level due to
indicates the direct inclusion of organic matter,     contamination. Most of local areas have been
particularity those arising from the excrement of     experienced with excessively high level of
animal and human species. Surface water may           nitrogenous compounds. The Groundwater
also get polluted ammonia due to industrial           Resource Development Board (GWRDB, 1989,
discharges. Groundwater drawn from strata             [3]) has reported the concentration of ammonia
overlay with clay may sometimes suffer                in surface and groundwater as presented in
deoxygenating and          comparatively large        Table 1. The ammonia concentration up to 19
quantities of free ammonia can arise from the         and 95 ppm have been reported in surface water
reduction of nitrate. In populated area,              and groundwater respectively. The ammonia
incompletely treated sewage or possibly               concentration on the surface and groundwater as
industrial effluent may be another source. The        reported by Amatya, 2004 is presented in Table
ammonia also sometimes found in groundwater           2. In drinking water, the ammonia should not
as a result of breakdown of portentous organic        exceed 1.5 ppm (WHO, 1990). The ammonia
matter and reduction under anaerobic                  concentration was found to exceed the WHO
conditions. Various sources of nitrogen in water      guideline values in both the surface and ground
                                                      waters. The ammonia nitrogen concentration up

International Conference on Science, Technology and Innovation for Sustainable Well-Being
(STISWB), 23-24 July 2009, Mahasarakham University, Thailand

to 125.07 ppm has been reported. The ammonia          P2, P3 and P4) were provided on the column to
nitrogen concentration increases as the depth of      take the sample from different depths. The
wells increases.                                      column is filled up with over burnt brick of sizes
Table1: Ammonia Nitrogen Concentration in             0.60 to 0.85 mm up to 80 cm height. The
Kathmandu Valley                                      influent ammonia nitrogen concentration was
                              Surface         Ground          fixed at 2.5 and 5 ppm. The experiments
                 WHO                                          were conducted at flow rates of 123.84
 Parameter                      water           water
              Guideline                                       m3/m2/day      (120    ml/min),     36.80
                            Max Min         Max     Min
                                                                3  2
 Ammonia                                                      m /m /day (130 ml/min) and 150.77
                  1.5        19     <0.1     95      0.1      m3/m2/day (145 ml/min). The schematic
 –N (ppm)
                                                              diagram of experimental setup is shown
Some methods such as adsorption, reverse              in Figure1.
osmosis, chemical precipitation, chemical
oxidation, electrolysis, gas stripping and
biological nitrification or denitrification can be
used for removal of ammonia from water (EPA,
1975, Culp R.L. and Culp G.L. 1971, Kansakar
B.R. 1986, Mc Carty P.L., Miller
D.G. and Short C.S.1972 and Short C.S., 1975).
Although the many of them proved to be
technically feasible but others factors such as
cost, operational requirements and aesthetic
considerations have not been found favorable in
some cases. For low concentration of ammonia
in water, adsorption of ammonia by using over
burnt brick in local level may be very practical
and economical. The main objective of this
study is to minimize the ammonia concentration
in surface water and groundwater and the              Figure 1: Schematic Diagram of Experimental Set Up
performance study of locally available
adsorption media like over burnt brick.               The flow was regulated by using Watson
                                                      inducer (MHRE MK 4 flow inducer) and
Table2: Ammonia Nitrogen Concentration of             Electrolab Peristaltic Pump (PP 50 VX). The pH
Deep Wells in Kathmandu Valley                        was measured by digital pH meter (DHA-3000-
                                                      1706-02) and the temperature was measured by
       Location           Ammonia-N (ppm)             simple thermometer graduated in oC. The
Lokanthali WTP               51-105                   ammonium       nitrogen      concentration   was
Kuleshor                      60-95                   measured       by       using     Ultra    violet
IOE Pulchowk Campus          40-117                   spectrophotometer as per the Standard Methods,
Balaju                        21-38                   1980.
Bhaisepati                    10-43                   3. Result and Discussion
                                                      The adsorption equilibria are the most important
                                                      physiochemical parameters, which help in
2. Methodology                                        defining the type and process of adsorption. The
The ammonia nitrogen adsorption on over burnt         ammonia nitrogen adsorption equilibria study
brick was carried out in column using fixed bed       using different particles sized over burnt brick
operation. The study was conducted in a small         adsorbents were conducted utilizing non flow
column having internal diameter of 4.2 cm and         agitated system. The adsorption of ammonia
length of 120 cm with upflow mode. A                  nitrogen was observed at equilibria in all
perforated plate with cotton was placed at the        particles sizes. Therefore contact time was
base of the column that acted as support for the      perceived at time taken for 90% adsorption from
media. Arrangements were made to measure the          the aqueous solution of adsorbate. It was noticed
loss of head during the operation. Four ports (P1,    that for all particles size the rate of adsorption

International Conference on Science, Technology and Innovation for Sustainable Well-Being
(STISWB), 23-24 July 2009, Mahasarakham University, Thailand

processed quite rapidly and attained equilibrium                          adsorbents were calculated to illustrate the time
gradually as presented in Figure 2. This appears                          dependence of the system. Although the removal
due to external surface reaction. Figure 2 shows                          of ammonia nitrogen was high initially, the rate
the removed NH3-N concentration and effluent                              gradually decreased to attain the equilibrium
NH3-N concentration as time progressed. The                               stage.
initial concentration start decreasing as time                            Table 3: Contact Time and Adsorption Rate Constant
increase, thus by increasing removed NH3-N
concentration.                                                                            Particle size Contact Adsorption rate
                                                                                             (mm)       time (hr)  constant
                                                                                  1         0.30-0.15        4         0.054
                                                         Effluent NH3-N           2        0.425-0.30       5.5        0.0615
  NH3-N (ppm)

                                                                                  3        0.60-0.425        6         0.0653
                4                                                                 4         0.85-0.60        7         0.1079
                                                         Removed NH3-N
                3                                                                 5         1.18-0.85        8         0.0977
                2                                                                 6         2.00-1.18       8.5        0.0898
                1                                                                 7         2.36-2.00        9         0.0846
                                                                                  8           >2.36         9.5        0.0763
                    0         5          10             15                Table 3 shows that as the particle size increases
                                  Time (hr)                               the adsorption rate constant also increase up to
                        Figure 2: Ammonia-N Removal                       particle size of 0.060 mm. However the
                                                                          adsorption rate constant decreases for the
Figure 3 shows the ratio of C/Co at various                               particle sizes from 0.850 to 2.36mm.The optimal
contact time, where C is ammonia nitrogen                                 value of adsorption rate constant was found as
concentration and Co is the initial ammonia                               0.1097 for particle size of 0.850-0.600 mm at
nitrogen concentration. The contact time and                              corresponding contact time is 7 hours.
adsorption rate constant for various particle                             3.1 Adsorption Isotherms
sizes at initial ammonia concentration of 5 mg/l                          The adsorption curves for various sizes-
is presented in Table 3. The contact time of                              adsorbents were applied to Langmuir’s and
smaller particle size was less as compared to                             Freundlich’s equations. The Freundlich’s curves
larger       particles sizes. The contact time                            fit better than Langmuir curve and also
increased as the particle sizes increased. The                            linearised. It can be observed that all the
contact time is calculated as 4 hours for particle                        isotherms of media seem favorable for the
size of 0.30 - 0.15 mm which increased to 9.5                             adsorption data. Typical examples of isotherm
hours for particle size greater than 2.36 mm. The                         test for media size of 2.36-2.0 mm are presented
effluent ammonia nitrogen concentration                                   in Figures 6 and 7, Similar patterns were noticed
decreases as the contact time increases.                                  for others particle sizes. In graphs, X and m are
                                                                          the weight of substance adsorbed (contaminant)
                                                                          by adsorbent and weight of adsorbent (media)
                1.0                                                       respectively.
                0.8                                                               0.01

                0.6                                                                                X/m = 0.0002Ce
                                                                                                      R = 0.8157

                0.2                                                          0.0001

                        0          5               10           15          0.00001
                                       Time (hr)                                         0              1              10
        Figure 3: Contact Time Vs C/Co                                                   Equilibrium Conc, Ce (mg/l)
The variation of contact time with respect to
particle size is presented in Figure 5. The                                       Figure 6: Freundlich’s Isotherm Test
contact times for various types and sizes of

International Conference on Science, Technology and Innovation for Sustainable Well-Being
(STISWB), 23-24 July 2009, Mahasarakham University, Thailand

                                                                                                               200                               0.12
                                        Ce/(X/m) = 852.46Ce + 3979

                                                                                Rate Constant, K (m 3/kg hr)
                       10000                                                                                   180

                                                                                                                                                        Adsorptive Capacity, No
                                               R2 = 0.3995                                                     160                               0.10
                       8000                                                                                    140                               0.08


                                                                                                                                                                (kg/m 3)
                       6000                                                                                                                                                             K
                                                                                                               100                               0.06
                       4000                                                                                                                                                             No
                                                                                                                60                               0.04
                                                                                                                40                               0.02
                          0                                                                                     20
                               0               2        4              6                                         0                               0.00
                                                                                                                     5.16       5.7       6.28
                               Equilibrium Conc, Ce (mg/l)
                                                                                                                            Flow (m/hr)
                         Figure 7 Langmuir Isotherm Test
                                                                                Figure 9: Adsorption Capacity and Rate Constant
3.2 Column Study                                                              3.3 Linear Regression Analysis
The column study was carried out for ammonia                                  In order to develop relationship between
nitrogen adsorption capacity in the fixed bed                                 ammonia removals, depth of media, flow rate
column containing over burnt brick. The                                       and service time, linear regression analysis was
ammonia nitrogen concentration at various                                     done using SPSS as a tool. The mathematical
flows and bed depths i.e. P1 (port at 20 cm                                   model developed is given below:
depth), P2 (port at 40 cm depth), P3 (port at 60
cm depth), and P4 (port at 80 cm depth) were                                  ΔN = C H 0.084 Q0.514 T 0.521                                                                       (1)
measured and their breakthrough curves are
presented in Figure 8.                                                        Where,
It was noticed that as flow decreased and or bed                              ΔN = Ammonia – N removed (ppm)
depth increased, the trend of effluent                                        H = Depth of media (cm)
concentration is flatter and vice versa. At the                               Q = Discharge to be supplied (lit/min)
time of attaining exhaustion the slope was more                               T = Service time (minute)
flat in low flow and less flat in high flow rate.                             C = Constant coefficient (C = Antilog (-1.267))
Figure 8 shows that the exhaust time at the                                   The above regression model can be used for
various depths of media at flow of 120 ml/min.                                design purpose i.e. size of treatment plant to
        1.0                                                                   adsorb ammonia nitrogen by using over burnt
                                                                 P2           brick. This model considers only the major
        0.8                                                      P3           parameters such as depth of media required,
                                                                 (P) Outlet   ammonia nitrogen concentration to be removed,

        0.6                                                                   service time and discharge while other
                                                                              parameters like temperature, pH remaining
                                                                              4. Conclusion
                   0               5               10       15
                                                                              Following conclusions have been drawn from
                                                                              the study.
                                       Time (hr)
                                                                              1. The ammonia nitrogen removal rate
                                                                                  increased with increase in contact time at
Figure 8: Breakthrough Curve for NH3-N Adsorption
                                                                                  the initial phase, which decreases with time
The rate constant (K) and adsorptive capacity                                     until steady state condition is attained.
(No) for over burnt brick of 0.850-0.600mm size                               2. The contact time and the rate of adsorption
are presented Figure 9. It can be seen at various                                 (K) increase with increase in particle size.
flow rates that as flow increases, the rate                                       The optimum value of adsorption rate
constant increases while adsorptive capacity                                      constant was found at particle size of 0.850-
decreases.                                                                        0.600 mm, and then rate of adsorption
                                                                                  decreased as the particle size increased.

International Conference on Science, Technology and Innovation for Sustainable Well-Being
(STISWB), 23-24 July 2009, Mahasarakham University, Thailand

3. Freundlich’s isotherms were found best to       [5]   Mc Carty, P.L.,, “Source of
   describe the ammonia nitrogen adsorption of           Nitrogen and Phosphorous in Water
   over burnt brick.                                     Supplies”, Journal of American Water
4. As the discharge increases, adsorption                Works Association, Vol. 59, No.3,
   capacity of over burnt brick decrease where           March 1967, pp.345-366.
   as rate constant and critical bed depth         [6]   Miller D.G. and Short C.S., “Costs of
   increase.                                             Water    Treatment”, The Trent
5. The linear regression mathematical model              Research      Programme,       Water
   developed will be helpful for calculating             Resources Board, Vol. 5, 1972.
   ammonia removal in fixed bed applications.      [7]   Short C.S. “Removal of Ammonia
                                                         from River Water”, Water Research
5. Acknowledgement                                       Centre,    Medranham      ,    Bucks,
I wish to express my deep sense of gratitude and         Technical Report TR-3, 1975.
sincere thanks to Prof. Dr. Bhagwan Ratna                Standard Method for the Examination
Kansakar and Associate Professor Mr. Iswar               of Water and Wastewater, APHA-
Man Amatya for their excellence guidance,                AWWA-WPCF, 15th Edition, 1980.
constant inspiration, regular monitoring and all   [9]   WHO, Health and Safety Guidelines,
round assistance that enabled me to bring this             1990.
research work in present form.
I extend my profound gratitude to Prof. Dr.
Vinod Tare of Environmental Engineering, IITK
for his valuable suggestions.
I express my sincere thanks and gratitude to Mr.
Mahesh Prasad Bhattarai, Coordinator of
Environmental Engineering Program of Institute
of Engineering, for his valuable suggestion
during literature collection.
My thanks also go to Asso. Prof Padma Sundar
Joshi of IOE for his all round supports. I would
also like to extend my appreciation to Mr.
Nagendra Bahadur Amatya for his valuable
suggestion during data analysis.
Finally, I would like to thanks to Mrs. Prabha
Karmacharya, Miss Goma Yakami, Mr. Keshab
Bhattari and Mr. Sagar Devkota for their kind
cooperation extended during the research work.

6. References
[1]   Amatya I.M., Ph.D. “Ammonia Removal
      in Water”, Directed study submitted in
      partial fulfillment of the requirement for
      Ph.D. Study, Institute of Engineering Aug.
[2]   Culp R.L. and Culp G.L. “Advanced
      Wastewater Treatment”, Van Nostrand
      Remold, New York, 1971.
[3]   GWRDB, A Report on Ground water
      Management Project in the Kathmandu
      Valley, JICA, 1989.
[4]   Kansakar B.R., “Nitrification of Water in
      Gravel Filters for Drinking Purpose”,
      Ph.D. Thesis, Tokyo University, Tokyo,
      Japan, 1986.


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