Eighteenth International Water Technology Conference, IWTC18
Sharm ElSheikh, 12-14 March 2015
SCENARIOS FOR GROUNDWATER REMEDIATION USING N15 IN NILE
DELTA
Zeidan, B. A. *, Aly, A.I.M. **, Rashwan, I. M. H.*, Ahmed, M.A. **, S.M. Ghoraba*
*Irrigation and Hydraulics Engineering Department, Faculty of Engineering, Tanta University,
Egypt.
**Egyptian Nuclear and Radiological Regulatory Authority (ENRRA), Cairo, Egypt.
Mail to: [email protected]
ABSTRACT
In the present study, groundwater pollution in the central part of the Nile Delta is investigated. Natural
chemical constituents and some contaminants of shallow groundwater and their distribution through the
whole region of the studied area are investigated. A combination study of laboratory and numerical
modeling are utilized. Numerical modeling for governing equations describing advective-dispersive
transport with multi rate mass transfer is utilized employing FDM. A three dimensional finite difference
groundwater model MODFLOW is used to deal with the hydrodynamics of the flow through porous
media. A groundwater solute transport simulator MT3DMS which can be communicated with
MODFLOW through data files, is utilized to solve the problem of contaminants transport and the change
of their concentration with time. Field measurements and experimental works were conducted on sixty
surface and groundwater samples collected from the study region. The collected samples were analyzed in
the Central Laboratory of Environmental Isotope Hydrology, ENRRA. Stable isotopic techniques
(Oxygen-18, Deuterium) were used to investigate the recharge sources, and Nitrogen-15 technique was
applied to help tracing sources and fate of nitrate contamination found in collected water samples. The
analysis indicated that vulnerability of the water resources to pollution is mainly related to the use of
excess fertilizers (NO3), the growing industrial activities, and sewage effluents. The sources for the higher
nitrate concentration appear to be mixing with sewage or manure and ammonium phosphate fertilizer.
Scenarios for groundwater remediation in Birma village employing extraction wells are presented.
Keywords: Groundwater contamination, numerical modeling, field experimentation, hydrochemistry,
environmental isotopes, 15N, MODFLOW, Nile Delta.
1 INTRODUCTION
The water resources in the Nile Delta region have experienced drastic events in the last four
decades since the operation of the High Aswan Dam. Many activities have impact on eutrophication and
contamination status, the ecological value and environmental condition of the Nile Delta region such as
agriculture development, industrial activities within the catchments and inadequate rural sanitation.
Excessive irrigation applications lead to water logging problems in vast areas of the region. Moreover, the
domestic, industrial, sewage and agricultural drainage to surface and groundwater with all known
effluents deteriorate the ecosystem in the Nile Delta. Recent increases in global population, together with
enhanced standards of living, have created greater demand on water resources, requiring improved
groundwater management. Understanding the groundwater recharge process is essential in protecting
groundwater source quality. Short transit times associated with the recharge process can potentially
adversely affect groundwater quality due to lack of attenuation time or contaminant decay. Residence
time estimation offers benefits to evaluating recharge water flow through the subsurface to groundwater
sources. In El-Gharbiya Governorate, central of Nile Delta, excessive use of sewage effluent and sludge,
over-fertilization, over-use of manures for irrigation purposes cause hazardous effects on plants, animals
and human health. In addition, discharge of liquid or solid wastes with different kinds of contaminants
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into the geologic environment causes groundwater deterioration. Numerical modeling techniques have
been successfully utilized for simulating groundwater movement and solute transport mechanism. The
well-known finite difference groundwater model MODFLOW has been proved to be an efficient
technique to simulate groundwater hydrodynamics and a solute transport model which can be
communicated with MODFLOW through data files MT3DMS, is widely employed to solve the problem
of contaminants transport and the change of their concentration with time. Nitrogen isotopic method has
been developed and successfully used in numerous case studies to identify nitrogen compounds pollution
sources in some countries. Nitrate derived from manure or sewage is usually characterized by δ15N values
greater than +10‰. It is therefore isotopically distinct from N in most synthetic fertilizers (0 ± 4‰), from
natural soil organic N (+4 to +9‰) and nitrate generated therein by microbial nitrification. The overall
objective of this study is to discriminate between these different sources of nitrate pollution in
groundwater using the hydro-chemical and isotopic approaches and simulate them numerically. The
purpose of this paper is to identify problems, knowledge, gaps and needs that deemed important to
improve water management in the Middle Delta as well as propose scenarios for groundwater remediation
and mitigation. A proposed groundwater remediation schemes for Birma region was presented.
2 STATE OF ART
The modeling of groundwater flow and contamination in the Nile Delta has been reported in the
literature by various researchers(1-10). Zaghloul, (1958) and (1984), proposed a new classification for Nile
Delta aquifers and its sources of pollution. The storage possibilities in different types of aquifers are
outlined. The transmitting capacity of the Delta aquifer is studied. The monthly discharges are computed
at various zones and a balance is made for gains and losses. Farid (1980) and (1985), discussed a detailed
description of the geological conditions of the Nile Delta aquifer and its management. The
hydrogeological and hydrological characteristics of the Nile Delta aquifer were determined. The sea
water wedge was described suggesting sea water intrusion of about 30 km far from shoreline whereas the
points of interface at distance of 80 km far from shoreline. Goamea (2000), studied the behavior of the
transition zone in the Nile Delta aquifer under different pumping schemes. The fresh groundwater
thickness increases with time, most probably due to increasing surface water diversions and also as an
effect of the construction of the High Aswan Dam. The most efficient scheme among many investigated
schemes is fresh water withdrawal with abstraction barrier in the transition and at the coast. The idea of
utilizing the scavenger well scheme in general has been examined as a tool for groundwater abstraction. It
is concluded that the scavenger well is applied in case of two different groundwater qualities. A unique
saline well could be used to control four or more fresh water wells at a certain distance (circle of
influence). RIGW/IWACO, (1990), studied the development and management of groundwater resources
in the Western Nile Delta Region. Groundwater development scenarios are evaluated with numerical
groundwater flow simulation using (TRIWACO) package. The model covers the major part of the
Western Nile Delta region and the adjacent desert. El Molla et al. (2005) developed data base and a three
dimensional groundwater model to simulate the behavior of groundwater system and its interaction with
surface water at western Nile Delta area. An overview of the Nile Delta and its water resources
assessment is presented by Zeydan (2005). Bear (1987) presented the basic equations of contaminant
transport in groundwater. He presented two component for hydrodynamic dispersion of the contaminant
concentration; advective transport which expresses the flux carried by the water at the average velocity
(as determined by Darcy’s Law) and dispersive transport. Dispersive flux is a macroscopic flux that
expresses the effect of the microscopic variation of the velocity. Dispersion in porous media refers to the
spreading of contaminants over a greater region than would be predicted solely from the average
groundwater velocity vectors. Shamrukh (2001) investigated the contamination of groundwater by
nitrogen and phosphate chemical fertilizers in the Tahta region of the Nile Valley Aquifer. The threedimensional groundwater flow and contaminant transport models; (MODFLOW & MT3D) were used to
predict the future concentration of NO3- and PO43- in shallow and deep groundwater. The availability of
groundwater for irrigation and public water supply for the present century were studied. An overview of
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advances in groundwater studies including modeling, tracing and management is presented by Zeydan
(2004). Wang (2005) presented a numerical solution for governing equations describing advectivedispersive transport with multi rate mass transfer between mobile and immobile domains. The solutions
of two illustrative examples obtained using the new approach agree with those obtained by existing semianalytical and numerical solution obtained using the transport simulator MT3DMS. Atta et al. (2005)
and Sharaky et al (2007) employed the hydrochemistry of major-ions (K+, Na+, Mg2+, Ca2+, Cl-, SO42,HCO3-, CO32-) together with trace elements (Fe, Mn, Zn, Pb, Cd, Cr, Cu, Ni) to constrain the
hydrochemical characteristics, source and salinization processes of the shallow coastal aquifer,
northwestern Nile Delta. The study aimed to obtain additional information on the possible contamination
with major elements, trace elements (heavy metals) and/or nutrients (NO3-, PO42-, NH4+). Salem (2006)
investigated the chemical contamination of the groundwater and surface water at the west Nile Delta. The
study revealed that the source of the contamination is mainly derived from either natural sources (drains
and canals) or from man-made sources (agricultural, domestic and industrial sources). The vulnerability
the water resources to the pollution is mainly related to the use of excess fertilizers (NO 3) and due to the
growing industrial activities and sewage effluent, in addition to the seepage of untreated wastes to the
surface water network. El-Fakharany (2009) studied the impact of local hydrogeological conditions and
human activities on water resources at the southeastern part of the Nile Delta (El Khanka area). Results
indicate that both surface water and groundwater in the study area are suffering from quality problems
related mainly to natural and human-related factors. High concentrations of salinity, major elements,
nitrate, and trace elements are detected in the water samples. Ahmed et al. (2009) utilizing isotopic and
hydro-chemical tracers to investigate nitrogen pollution sources of surface water and groundwater system
for proper management and decreasing pollution of freshwater resources in the Middle Delta, Egypt.


Results indicate that Rosetta Branch has higher NH4 concentration and enriched δ15N- NH4 and δ15N-
NO3
NH4
values than Damietta Branch due to disposal of Tala sewage drain, with highly enriched δ 15N-
value, in it. Ghoraba (2009) and Ghoraba et al. (2012) studied the groundwater quality
management in Middle Nile Delta through a combination of laboratory and numerical modeling works.
Environmental isotopes techniques were used to investigate the recharge sources and the nitrogen
compounds pollution sources. MODFLOW and MT3DMS were employed numerically by applying the
method of finite differences for solving the three dimensional problem. The obtained results include the
prediction of water levels and solute concentration values distribution in the area at different times. A
scenario for remediation is proposed. Hussin and Mousa (2012) used environmental isotopes and
geochemical data to improve the water management in the Nile river system. Lo Russo and Taddia
(2012) developed an effective and economically-sustainable land management strategy to protect
subsurface water resources from anthropogenic pollution in which combined general safeguards were
applied to the whole aquifer recharge area with specific local land use restrictions in the proximity of the
abstraction point (i.e. WHPAs).
3 PROBLEM STATEMENT
The chosen area to conduct the study is El-Gharbiya Governorate. It extends between latitudes
30° 36` - 31° 09` N and longitude 30° 45` - 31° 15` E. It includes more than 1943.51 km2 in the central
part of the Nile Delta. The area is bounded on the west by the left branch of the Nile River “Rosetta” and
on the east by the right branch “Damietta”. The Governorate extends into Kafr El-Sheikh in the north and
Monofeya Governorate in the south. The Governorate consists of eight centres with very dense population
reaches about 4,011,921 inhabitants with only 30% of the governorate is served by sewage network.
Septic tanks, rural latrines and injected wells are the means used for sewage disposal in the other parts of
Governorate. The land area is a low elevation plain where sediment is deposited at the mouth of Nile
River, it is the most suitable land for intensive agriculture. Excessive fertilizers and pesticides
applications are required for plant growth. This leads to water quality problems in vast areas of the region.
Significant proportions of chemicals used is leached into the water system. In EL-Gharbiya Governorate,
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extensive man-made drainage systems are found which are particularly noticeable in traditionally
cultivated land areas and have been extended to some of the newly reclaimed areas. Large volumes of
domestic and untreated industrial effluent are still discharged into the water channels or directly to the
river branches. Kafr El-Zyat city is considered as one of the most important industrial cities in Egypt. The
most of industrial plants constructed at Kafr El-Zyat city on the banks of the Rosetta branch directly
discharge their effluents into the Rosetta branch without any treatment. The estimated flow of industrial
wastewater discharge to the Rosetta branch is about 0.05 million m3/day, (Daifullah et al., 2003). These
industries were identified as being the major source of water pollution in this area. The Quaternary and
Pliocene water bearing formations in the central part of the Nile Delta comprise a leaky aquifer system
intercalated by semi-pervious clay and silty layers acting as an aquitard. This Holocene aquitard caps the
main aquifer that belongs to the Pleistocene which forms the groundwater reservoir in itself. The
formations are underlain by an impermeable base of Pliocene clay deposits which act as an aquiclude.
The two hydrological units forming the semi-confined aquifer are hydraulically connected with each of
them having its own water level. The transmissivity of the aquifer varies from 3000 to 5000 m2/day and
the hydraulic conductivity ranges from 50 to 100 m/day. The effective porosity varies from 15 to 18% and
the storage coefficient ranges between 0.01 and 0.001.The differences between the piezometric levels of
the aquifer and the shallow water table levels in aquitard don’t exceed more than 2 m, (Abd El-bary,
2004). Figure (1) shows the hydrogeological map of the studied area. The influence of surface water
bodies located inside or in the boundary of the region on groundwater quality is studied. The change of
concentration of contaminants with time is estimated, and the nitrogen-15 (15N) technique is used in the
evaluation and interpretation of nitrate and ammonium pollution sources of ground and surface water
(artificial nitrogen fertilizers, organic fertilizers and sewage). The soil and aquifer properties, the fluid
flow conditions combined with the physical and chemical characteristics of the contaminant create a three
phases problem of considerable complexity. The objective of the study is to evaluate the groundwater
quality for different purposes and to determine the interaction between groundwater aquifers and manmade sources which produce hazardous fluid waste.
Figure 1. The groundwater aquifers in the studied area
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4 THEORETICAL APPROACH
By combining continuity equation with Darcy’s velocities, the partial differential equation governing
the unsteady flow of water in a compressible confined aquifer of uniform thickness b, for the anisotropic
media the equation reads following Harr (1962):
 (K h)   (K h)   (K h)  S h
x x x y y y z z z b t
(1)
where Kx, Ky, and Kz are the coefficients of permeability in x, y, z directions, S is the aquifer storativity or
the storage coefficient and h is the potential head. Solute transport in groundwater aims at computing the
concentration of a dissolved chemical species in an aquifer at any specified time and place. Changes in
chemical concentration occur within a dynamic groundwater system primarily due to four distinct
processes: advective transport; hydrodynamic dispersion; fluid sources; and reactions. From principal of
mass conservation, the flux q defined by following Bear (1987):
∂C
Θ ∂t
∂q
∂x
=
-
(2)
Where; C contaminant concentration; Θ water content in the porous media, and q the mass flow rate in x
direction. The flux q consists of both advection and dispersion components. Advective flux expressing
the flux carried by the water at the average velocity as determined by Darcy’s Law. Dispersive flux is a
microscopic flux that expresses the effect of the microscopic variation of the velocity. Equation (2) can be
written as:
C [D 2C D 2C D 2C ][u C v C wC]
x
y
z
t
x2
y2
z2
x y
z
(3)
∂C
where: ∂t
rate change in concentration of contaminant; (u,v,w) Darcian velocities in x, y, z
directions; and (Dx, Dy, Dz) Dispersion coefficients in x, y, z directions. A generalized partial differential
equation describing the fate and transport of contaminants of species k in three-dimensional, transient
groundwater flow systems can be formulated as follows, Bear (1987):
k
  Ck  
(nC)

 nDij
 nvsiCk qsCsk Rn

t
xi 
xj  xi


(4)
where:
Ck
dissolved concentration of species k, ML-3;
n
porosity of the subsurface medium, dimensionless;
t
time, T;
xi
distance along the respective Cartesian coordinate axis, L;
Dij hydrodynamic dispersion coefficient tensor, L2T-1;
vsi
seepage or linear pore water velocity; LT-1; it is related to the specific discharge or Darcy flux
through the relationship, vsi=qi/n;
qs volumetric flow rate per unit volume of aquifer representing fluid sources (positive) and sinks
(negative), T-1;
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Csk
R
Sharm ElSheikh, 12-14 March 2015
concentration of the source or sink flux for species k, ML-3;
-3 -1
n chemical reaction term, ML T .
The left-hand-side of equation (4) can be expanded into two terms, i.e.,
(nCk )  nCk Ck n  nCk qCk
t
t
t
t s
(5)
where qs  n t is the rate of change in transient groundwater storage, T -1. Considering only two basic
types of chemical reactions, i.e., aqueous-solid surface reaction; sorption which refers to the mass transfer
process between the contaminants dissolved in groundwater (aqueous phase) and the contaminants sorped
on the porous medium (solid phase) and first-order rate reaction, the chemical reaction term can be
expressed as follows, Bear ( 1987):
Rn  b C 1nCk 2bCk
t
k
(6)
where:
b
Ck
bulk density of the subsurface medium, ML-1; it is the ratio of the mass of dried soil to total
volume of soil.
concentration of species k sorbed on the subsurface solids, MM-1;
first-order reaction rate for the dissolved phase, T-1;
1
2 first-order reaction rate for the sorbed (solid) phase, T-1.
Substituting equations (6) and (5) into equation (4) and dropping the species index for simplicity of
presentation, equation (4) can be rearranged and rewritten as, Bear ( 1987),


nC  b C   nDij C    nvsiCqsCs qsC1nC2bC
t
t xi  xj  xi
(7)
Equation (7) is essentially a mass balance statement, i.e., the change in the mass storage (both dissolved
and sorped phases) at any given time is equal to the difference in the mass inflow and outflow due to
dispersion, advection, sink/source and chemical reactions. Local equilibrium is often assumed for the
various sorption processes (i.e., sorption is sufficiently fast compared to transport time scale). When the
local equilibrium assumption is invoked, it is customary to express equation (7) in the following form,


RnC   nDij C    nvsiCqsCs qsC1nC2bC
t xi  xj  xi
(8)
where R is referred to as the retardation factor, which is a dimensionless factor defined as:
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R 1 b C
n C
(9)
The linear isotherm assumes that the sorped concentration
C is directly proportional to the dissolved
concentration C and the retardation factor is independent of the concentration field;
C  Kd.C
(10)
R 1 b Kd
n
(11)
where Kd is the distribution coefficient of the solute in the porous medium,L3M-1. It depends on the solute
species, nature of the porous medium, and other conditions of the system, Bear (1987).
5 NUMERICAL MODELING
Because aquifers are heterogeneous and have complex boundary conditions, exact analytical
solutions to the governing equations can not be obtained directly. Instead, numerical methods are used, in
which the continuous variables of the governing equations are replaced with discrete variables that are
defined at grid blocks (or cells or nodes). Thus, the continuous differential equation, which defines
hydraulic head or solute concentration everywhere in the system, is replaced by a finite number of
algebraic equations that defines them at specific points. However, numerical methods yield only
approximate solutions to the governing equation; they require discretization of space and time. The
variable internal properties, boundaries, and stresses of the system are approximated within the
discretized format. In general, the finer the discretization, the closer the numerical solution will be to the
true solution. MODFLOW code is a commercial software designed to describe and predict the behavior of
groundwater system, Chiang and Kinzelbach (1998). This model employed Finite Difference techniques
to simulate the hydrodynamic of the groundwater flow under non-equilibrium conditions in a
heterogeneous and anisotropic medium. This model is a well established computer code, which has been
successfully used in variable groundwater flow studies. Many models or programs can be stand alone
codes or can be integrated with MODFLOW. These programs communicate with MODFLOW through
data files. In this work the further development solute transport model MT3DMS is chosen for the
Modular 3-Dimensional Transport model. MT3DMS can be used to simulate changes in concentrations of
miscible contaminants in groundwater considering advection, dispersion, diffusion and some basic
chemical reactions, with various types of boundary conditions and external sources or sinks, Chunmiao
and Patrick (1999). MT3DMS is designed for use with any block-centered finite-difference flow model,
such as the modular finite-difference groundwater flow model, MODFLOW, under the assumption of
constant fluid density and full saturation. It simulates solute transport by using the calculated hydraulic
heads and various flow terms saved by MODFLOW. It is based on the assumption that changes in the
concentration field will not affect the flow field significantly. The present codes are utilized in the present
study for the following purposes: prepare through chemical analysis as well as collection from different
sources the data needed for the model application; assign the proper flow and boundary conditions that
represent the actual field conditions as close as possible; calibrate the models and check the compatibility
of the input data and study and analyse the results.
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6 MODEL VERIFICATION
The groundwater flow model MODFLOW was verified using two measured groundwater level contour
maps of regions located in Egypt: case study no. 1: The central part of the Nile Delta aquifer (RIGW, 1990) and case
study no. 2: The Southern part of Cairo studied by Saltout, (1996). In the central part of the Nile Delta, the water
levels in the Nile Branches; Rosetta on the west and Demietta on the east, which are bounding the area, are
considered as a fixed head boundary conditions. The southern boundary is a flux boundary with an inflow rate
variables along the boundary. The groundwater inflow rate is calculated from the hydrogeological map of the region
by applying Darcy's Law. Considering verification of case study no. 1, a good agreement between the MODFLOW
results and the groundwater levels presented in the hydrogeological map is shown in Fig. (2). Considering
verification of case study no. 2, a good comparison between the actual field results and those obtained from the
MODFLOW model is noticed in Fig. (3a &b).
(a): Calculated groundwater level contour map by MODFLOW,
(a) MODFLOW results (b) Measured groundwater level contour map (May 1995)
Figure 2: Verification of MODFLOW Model, case study no. 1 The Southern part of Cairo
After RIGWA (1990)
Calculated by MODFLOW
Figure 3: Measured and Calculated groundwater level contour map, case study no. 2
The computer program of solute transport simulation MT3DMS paired with MODFLOW were verified
using one of the test cases that was proposed by Oldenburg & Pruess, (1995). This test case is addressed to model
groundwater flow over a hypothetical salt dome. After completing the flow simulation the finite difference transport
model can be used. Fig. (4a &b) shows the results presented by Oldenburg, & Pruess, (1995) and the present
numerical model MT3DMS respectively. A good agreement between the two results is noticed.
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(a) MT3DMS
simulation
(b) Oldenburg and Pruess solution
Figure 4: Results of the salt dome problem- computed salinity contours.
7 CASE OF STUDY: BIRMA VILLAGE
The chosen area to conduct the numerical work as micro-scale study is Birma village where the concentration
values of ammonium contaminant are the up most according to hydro-chemical analysis results. It lies at the central
part of El-Gharbiya Governorate and belongs to Tanta center. The region to conduct the study looks almost like
square shape with length of 1.76 km and a width of 1.5 km. It is surrounded by Birma Drain at north, Omm Halaka
Canal at south, Omm Abd-Alla Canal at east and Nashart Al-Aalla Drain at west. Lateral boundaries of the
modeling area had been defined at constant-head boundary.
7.1.
Hydrochemistry And Stable Isotopes
From the studied area, representative groundwater samples from the Quaternary aquifer were obtained from
34 wells selected on the basis of geographical distribution. Most of the selected wells are used for irrigation and
domestic uses and their depths range from 13 to 60 m. Other samples were also collected from the drain and canals
waters (Figs. 5,6). All the water samples were collected for chemical and isotope analyses. Electrical conductivity
(EC), bicarbonate, dissolved oxygen (DO), temperature and pH measurements were measured in situ. Water samples
were filtered using 0.45 μm pore-size papers for measuring major cations and anions using Dionex-DX600 Ion
Chromatograph. Atomic absorption spectrometer was employed for the determination of the metals (Fe 2+ and Mn2+).
Delta O-18 was analyzed using the carbon dioxide equilibration technique and δD was analyzed using a hydrogen
equilibration technique at 18oC. For nitrogen isotope analysis, modified diffusion method was used for triplicate
determination of ammonium and nitrate in water. They were converted to N2 gas by reacting with LiOBr, Ahmed et
al. (2009). Nitrogen, oxygen, and hydrogen isotope ratios were obtained using isotope ratio mass spectrometer
(Thermo Quest DeltaplusXL). All stable isotope ratios are expressed in per mil (‰) notation:
δ=
Rsample Rstandard
1000‰
Rstandard
(12)
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31.1
31.1
31
31
30.9
30.9
30.8
30.8
30.7
30.7
30.6
30.6
30.7
30.8
30.9
31
31.1
31.2
31.3
30.7
31.4
30.8
Figure 5.a: Distribution of canals
in the studied area
30.9
31
31.1
31.2
31.3
31.4
Figure 5.b: Distribution of drains
in the studied area
42
31.1
0
10
41
20 Km
18
19
17
6
38
31
15
24
8
51
9
40
50
2
37
30.8
52
35
53
36
3
11
56
28
44
43
27
58
22
1
21
55
46
23
10
13
54
45
14
30.9
20
26
7
4
25
16
39
5
29
57
12
60
32
30
33
48
31
30.7
Groundwater samples
47
49
34
Canals samples
59
Drains samples
30.6
30.7
30.8
30.9
31
31.1
31.2
31.3
31.4
Figure 6: Location map of surface and groundwater samples
where R is the 15N/14N, 18O/16O, or 2H/1H ratio of the sample and the standard, respectively. Delta N-15 values are
reported with respect to air, while δ18O and δ2H values with respect to Vienna Standard Mean Ocean Water
(VSMOW). The analytical errors are ±0.5‰, ±0.1‰, and ±1‰, respectively. All the previous analyses were carried
out in the Central Laboratory for Environmental Isotope Hydrology, Egyptian Nuclear and Radiological Regulatory
Authority (ENRRA), Cairo, Egypt. A detailed description of the analysis procedure and results of hydrochemistry
and isotopes is given by Ahmed et al. (2009).
7.2.
Groundwater Flow Simulation
A three-dimensional grid is constructed to bound Birma sub-regional groundwater model. The grid cell size
in the horizontal plan of the model is 20m by 20m, requiring the modeled area to be subdivided into 75 rows and 88
columns. Fig.(7) illustrates the location map of Birma region and the horizontal grid of the modeling area. The
aquifer system has been subdivided into seven modeling layers in the vertical direction. MODFLOW uses the
elevation of top and bottom of the aquifer layer to calculate the aquifer thickness for each cell node. The value of the
first layer top has been changed according to the nature topography of the area by the grid SURFUR tool and saved
as spreadsheet file accepted by MODFLOW package. The saturated part of the silt-clay cap layer was modeled as
two layers of 7m constant thickness. Layers 3 through 7 were assigned a constant thickness for each layer; 6, 6, 5, 5
and 4 m respectively. This vertical discretization was chosen according to the depth and screen length of the
production wells that the groundwater samples were collected from.
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Eighteenth International Water Technology Conference, IWTC18
Sharm ElSheikh, 12-14 March 2015
Figure 7: Calculated water levels contour map in Bima region and direction of groundwater flow.
The steady-state case in MODFLOW was adopted to simulate the flow in Birma region. The hydraulic
properties of the stratigraphic units have been taken from the previous work conducted by Ghoraba (2009). The
horizontal hydraulic conductivity is assumed to be 10 m/day for the silt-clay cap. It ranges among 50 and 100 m/day
for the sand-gravel stratigraphic units. The vertical hydraulic conductivity is assumed to be 10 percent of the
horizontal hydraulic conductivity. The heads at the water boundaries have been based on the 1:100000 scale
hydrogeological maps of Middle Delta region by RIGW (West Tanta and East Tanta). The effective porosity is
assumed as constant average value of 0.18 and the transmissivity is assumed as constant average value of 4000
m2/day for the Pleistocene aquitard. After complete entering of the data required for building the model, it is allowed
to run. The calculated steady state groundwater levels and the direction of groundwater flow are presented in Fig.(7).
After steady state runs successfully the model becomes ready to run in the transient condition (time dependant
conditions). The heads obtained from the steady state simulation are used as starting heads to the transient analysis.
Time parameter is converted into transient. A simulation period of 7200 days (20 years) is applied. This simulation
time is subdivided into four time interval. Accordingly, heads and then the considered contaminant concentrations
could be obtained every five years (1800, 3600, 5400 and 7200 days).
7.3.
Solute Transport Simulation
In the present study, MT3DMS was used to simulate ammonium contaminant variation in Birma region. It
can be used to simulate changes in concentrations of miscible contaminants in groundwater considering advection,
dispersion, diffusion and some basic chemical reactions following equation (7). The same grid configuration used in
the groundwater flow modeling was used in the solute transport simulation, Fig.(7). The considered boundary
conditions in the transport model are surface and groundwater levels together with the other data and results of the
flow model in addition to the resulted ammonium-nitrogen concentrations from chemical analysis. The value of bulk
density for the entire domain was taken as 1.5 kg/m3 and the distribution coefficient of the solute in the porous
medium was assumed as 0.5 mL/g.
8
NUMERICAL RESULTS AND ANALYSIS
The chemical analysis of the groundwater samples show large variations of dissolved ions concentrations
with high salinity in some samples. The salinity map drawn from a representative set of 34 groundwater samples is
shown in Fig. (8). Total dissolved solids show large spatial variations between 320 and 6112 mg/L, while dissolved
oxygen (DO) range between 0.85 and 4.89 mg/L with a mean value of 2.21 mg/L. Drains water samples have the
HCO
SO2
highest DO, K+,
3 and
4 concentrations with mean values of 7.8, 11, 373 and 80 mg/L, respectively,
Table 1. In comparison to canals water, drains show higher TDS, Na +, Ca2+, Mg2+ and Cl- concentrations with mean
183
Eighteenth International Water Technology Conference, IWTC18
Sharm ElSheikh, 12-14 March 2015
values of 839, 137, 59, 27 and 141 mg/L, respectively, which could be attributed to agricultural activities and
discharge of industrial, domestic and sewage wastes in it. Zifta drain has the highest salinity which reached 1357
mg/L, Ahmed et al. (2009).
Table (1): Statistical comparison of the concentrations of chemical constituents between groundwater,
drains and canals water after Ahmed et al (2009).
Groundwater
Drains
Canals
Constituents
Range
Mean  SD
Range
Mean  SD
Range
Mean  SD
pH
7.79  0.25
7.4 - 8.4
7.3 - 9.5
7.83  0.57
7.3 - 8.3
7.86  0.36
TDS (mg/L)
320 - 6112
1050  1242 397 - 1357
839  230
262 - 483
359  77.5
EC (μS/cm)
500 -9550
1646  1938 820 - 2120
1325  335
410 - 755
561  121
DO (mg/L)
0.85 - 4.89
2.21  0.97
0.47 - 9.95
7.8  0.57
4.59 - 6.78
5.64  0.78
27 - 1667
219  358
42 - 216
137  46.9
26 - 58
41  12.3
0.6 - 24.1
5.75  4.7
3 - 36.7
11  8.1
1.3 - 11.2
4.9  2.55
8 - 328
70  54.7
27 - 83
59  14.9
23 - 49
35  8.5
4 - 214
33  41.6
14 - 37
27  7.1
10 - 17
12  2.2
186 - 845
313  137.5
157 - 641
373  112
95 - 283
181  50
Cl (mg/L)
37 - 3499
365  700
37 - 243
141  62
15 - 70
41  12.9
SO42 (mg/L)
1.2 - 539
41  90.5
23 - 201
80  49.3
17 - 70
37  15.3
+
Na (mg/L)
+
K (mg/L)
2+
Ca (mg/L)
2+
Mg (mg/L)
HCO3 (mg/L)
-
31.1
31
30.9
30.8
30.7
0
10
20 Km
30.6
30.7
30.8
30.9
31
31.1
31.2
31.3
31.4
Figure 8: Areal distribution of total dissolved solids (TDS) in mg/L for groundwater samples
Stable isotopes of oxygen (δ18O) and hydrogen (δD) were used in this study to determine the origin of
water and to characterize possible mixing of different water sources of water in the Quaternary aquifer. Results of
oxygen and hydrogen isotope analyses (δ18O and δD) of the groundwater, representing the Quaternary aquifer in the
middle Delta, Table 2, and drains and canals water samples, Table 3, are plotted with respect to GMWL, Fig. 9.
Isotope data for precipitation and Nile River water before and after erection of the High Dam are also included in
Fig. 9. The groundwater isotope data shows a range of variation from -1.58 ‰ to +2.8 ‰ and from -5.23 ‰ to +28.5
‰ for δ18O and δD, respectively. The large amplitude of isotope variations indicates the complexity of its source.
Most of the groundwater samples have isotopic contents which lie on a mixing line between the two signatures of
Nile River.
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Eighteenth International Water Technology Conference, IWTC18
Sharm ElSheikh, 12-14 March 2015
50
Groundwater
Drains water
40
GM
Canals water
L
Nile before High Dam
30
Delta D ‰
W
Nile water
Precipitation
20
10
0
-10
-20
-4
-3
-2
-1
0
1
2
3
4
5
6
Delta O-18 ‰
Figure 9: Relation between delta O-18 and delta D for surface and groundwater samples
NH
NO
Nitrogen concentrations and isotopic ratios of
4 and
3 were analysed in the collected canals,
drains and groundwater samples (Tables 2 & 3) in order to evaluate the sources and migration process of nitrogen
pollution. Ammonium concentrations of groundwater samples are less than 3.8 mg/L. About 38% of these samples
showed values above the maximum drinking standards of World Health Organization (WHO, 2004) of 0.5 mg/L.
Spatial distribution of ammonium ion in the groundwater is shown in Fig. (10) while Fig. (11) shows the spatial
NH
15
patterns of δ15N4 values in the studied area. As can be seen from the map, relatively depleted δ N values of 2.84 to +2.43‰ are mainly found in the central and western part of the studied area. These areas are affected by the
application of synthetic fertilizers. By contrast, the north and south-eastern areas have δ15N values >+4‰ indicating
soil organic nitrogen or seepage of raw sewage (untreated domestic effluents) replenishing the aquifer, particularly
NH
in the populated zones. Therefore, the natural nitrogen isotopic composition of
4 in the Middle Delta depends
on topographical variations, geology, groundwater flow direction, other sources of contamination and general
proximity to the agricultural sources. Figure (12) plots δ15Nconcentrations.
NH4 values for the groundwater samples versus their

Many other processes affect the concentration of NH4 in the groundwater, such as plant uptake,
immobilization by microbes, fixation in clay minerals, etc. Groundwater samples in the Quaternary aquifer have
nitrate concentrations range from 0.06 to 7.35 mg/L, the spatial variability of these concentrations are shown by Fig.
(13), (Ghoraba, 2009). Relationship between nitrate concentrations and iron and manganese levels are shown in Fig.
(14). Denitrification is accompanied by the appearance in solution of Mn2+ and Fe2+ ions if the corresponding
minerals occur in the aquifer. In these samples, the Mn 2+ and Fe2+ concentrations are only high where the nitrate
levels are lowest. Figure (15) shows how the lowering in nitrate values correlates with an exponential increase of
δ15N, according to the relation: δ15N = 24.9 – 2.56 ln NO3 (r2 = 0.91) with an enrichment factor equal to -2.56‰.
Table2: Stable Isotopes And Ammonium, Nitrate, Iron, And Manganese Concentrations of Groundwater
Samples After Ahmed et al (2009).
Sample
Sample
δ18O
δD
NH4
δ15N- NH
4
NO3
δ15N- NO
3
Fe2+
Mn2+
No.
1
2
3
4
5
6
7
8
9
Identity
well (1)
well (2)
well (3)
well (4)
well (5)
well (6)
well (7)
well (8)
well (9)
‰
1.06
0.26
0.12
0.45
0.83
2.8
1.2
-0.93
-0.04
‰
12.4
6.95
7.99
13.36
11.53
23.63
13.99
1.42
4.95
mg/L
0.44
1.18
1.86
2.36
0.14
0.34
0.10
0.32
0.19
‰
-0.28 ± 0.11
1.90 ± 0.21
1.25 ± 0.06
-2.51± 0.91
---1.50 ± 0.62
---2.54 ± 0.35
---
mg/L
0.31
0.59
0.94
0.82
0.45
0.82
0.06
0.98
1.00
‰
-------------------
mg/L
2.12
1.32
1.00
0.72
0.74
1.12
0.18
0.85
2.60
mg/L
1.07
0.73
0.61
0.95
0.39
0.41
0.45
0.41
0.66
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Eighteenth International Water Technology Conference, IWTC18
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10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Well (10)
Well (11)
Well (12)
Well (13)
Well (14)
Well (15)
Well (16)
Well (17)
Well (18)
Well (19)
Well (20)
Well (21)
Well (22)
Well (23)
Well (24)
Well (25)
Well (26)
Well (27)
Well (28)
Well (29)
Well (30)
Well (31)
Well (32)
Well (33)
-1.18
0.15
0.94
1.36
0.19
-1.58
-1.02
-1.21
0.62
-0.28
-0.21
0.35
0.91
0.17
0.38
-0.08
-0.13
0.71
-0.2
1.47
0.79
2.55
-0.52
1.66
-2.07
10.55
14.5
15.76
7.42
-2.84
-2.36
-5.23
6.9
2.25
3.87
9.99
12.03
10.83
10.8
4.25
7.81
9.52
7.85
19.65
12.28
21.86
4.7
19.04
0.26
0.23
1.18
3.37
0.72
0.33
0.41
0.19
3.70
3.81
0.99
0.21
0.15
0.23
0.78
0.22
0.05
0.29
0.38
0.67
0.66
0.16
0.39
0.68
--0.06 ± 0.69
-1.05 ± 0.78
-2.37 ± 0.21
2.43 ± 0.19
-0.57 ± 0.63
7.14 ± 1.1
--4.59 ± 0.46
4.66 ± 0.81
1.10 ± 0.73
1.05 ± 0.98
---0.70 ± 0.11
-2.84 ± 0.22
-2.69 ± 0.52
-----2.13 ± 0.1
4.98 ± 0.64
-2.71± 0.16
---1.58 ± 0.32
4.05 ± 0.54
1.62
0.61
0.71
0.82
0.65
1.48
2.98
1.70
1.06
5.44
7.35
4.56
0.14
0.82
3.56
2.94
1.89
0.14
2.12
1.46
0.25
0.75
1.15
1.08
------------22.5± 0.96
----20.1± 0.85
20.2 ± 0.54
21.2 ± 0.32
----21.3 ± 0.52
22.1± 0.36
----23.1± 0.72
-----------
3.13
1.20
1.33
3.20
1.53
0.32
0.58
1.62
4.90
0.40
0.24
0.42
0.38
0.95
0.13
0.14
1.32
3.25
7.30
3.30
0.88
1.58
2.50
2.81
0.57
0.5
0.82
1.12
0.64
0.46
0.23
0.35
0.31
0.21
0.25
0.28
0.44
1.1
0.25
0.32
0.31
1.1
0.26
0.58
0.47
0.46
1.2
1.25
34
Well (34)
2.54
28.53
0.19
---
0.93
---
0.56
0.5
31.1
31.1
31
31
30.9
30.9
30.8
30.8
30.7
30.7
0
30.6
30.7
30.8
10
30.9
0
20 Km
31
31.1
10
20 Km
30.6
31.2
31.3
31.4
30.7
Figure 10: Areal distribution of NH4+ conc. in
mg/L for groundwater samples
30.8
30.9
31
31.1
31.2
31.3
31.4
Figure 11: Areal distribution of δ15N-NH4+
values for groundwater samples
Table 3: Stable Isotopes and Ammonium and Nitrate Concentrations of Surface Water Samples
Sample
Type
No.
Drains
Sample
Sample Name
δ18O
δD
NH4
δ15N- NH4

NO3
δ15N- NO
3
35
Ganag Drain
‰
1.63
‰
16.72
mg/L
1.61
‰
9.44 ± 0.62
mg/L
44.42
‰
8.1± 0.21
36
Ebshway Drain
3.98
28.23
1.22
7.94 ± 0.32
23.96
9.25 ± 0.56
37
Tala Drain
3.61
28.59
2.46
11.84 ± 0.7
17.45
9.67 ± 0.57
38
Ebyar Drain
4.90
32.08
6.24
10.6 ± 0.63
2.30
16.38 ± 0.3
39
Qotor Big Drain
3.93
29.02
5.56
8.35 ± 0.25
8.87
13.5 ± 0.81
40
Seperpay Drain
2.19
23.39
35.01
5.48 ± 0.48
3.13
17.11± 0.81
41
El-Gharbia Main Drain
5.66
35.90
17.48
5.54 ± 0.49
2.05
21.8 ± 0.51
186
Canals
Eighteenth International Water Technology Conference, IWTC18
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42
No.5 Drain
4.15
36.40
6.86
4.8 ± 0.68
3.16
20.7 ± 0.36
43
Tile Drain
3.54
29.09
0.66
---
0.13
---
44
Mehalat Roh Drain
3.30
25.69
7.53
6.62 ± 0.85
3.63
18.6 ± 0.55
45
Zifta Drain
2.61
27.48
33.25
11.08 ± 0.9
13.23
14.1± 0.89
46
Omar Beah Drain
3.73
33.34
7.02
5.8 ± 0.19
13.66
11.3 ± 0.41
47
Kla Elbab Drain
3.15
26.33
8.07
7.3 ± 0.56
3.65
14.8 ± 0.69
48
El-Khadrawia Drain
3.48
29.75
15.64
7.03 ± 0.83
3.64
12.6 ± 0.58
49
Wasef Drain
3.58
31.45
1.55
6.43 ± 0.63
31.38
8.95 ± 0.47
50
51
52
53
54
55
56
57
58
59
60
Rosetta Branch (1)
Rosetta Branch (2)
El-Qasid Canal
Bahr Seef
Bahr Shibin
Damietta Branch (1)
Mit Badr Canal
EL-Rayah El-Abacy
El-Qurashiya Canal
Damietta Branch (2)
Tanta Navigation Canal
4.16
3.82
4.28
3.94
3.74
3.89
3.39
3.37
3.48
3.41
3.30
29.26
30.36
31.77
29.66
31.14
29.45
28.05
29.17
29.88
28.22
28.69
2.52
2.62
0.34
0.45
0.83
0.70
1.06
0.63
1.82
0.41
0.50
7.45 ± 0.09
7.53 ± 0.25
-0.32 ± 0.01
-0.42 ± 0.63
5.0 ± 0.41
1.0 ± 0.21
3.07 ± 0.06
5.79 ± 0.08
-0.38 ± 0.11
0.95 ± 0.05
1.32 ± 0.25
1.04
1.63
1.33
1.35
1.57
2.80
0.91
0.76
0.46
1.18
0.47
14.53 ± 0.2
14.47 ± 0.4
------9.37 ± 0.14
------11.55 ± 0.1
---
8
31.1
6
Delta NH4-N ‰
1819
31
4
30.9
2
0
30.8
-2
30.7
-4
30.6
0
0
1
2
3
4
30.7
30.8
10
30.9
20 Km
31
31.1
31.2
31.3
31.4
NH4-N (mg/L)
Figure 12: Relation between δ15N-NH4+ and
ammonium concentrations for groundwater samples
Figure 13: Areal distribution of nitrate concentrations in mg/L for
groundwater samples
8
1.4
(a)
(b)
1.2
Mn (mg/L)
Fe (mg/L)
6
4
1.0
0.8
0.6
2
0.4
0
0.2
0
2
4
6
8
0
NO3 (mg/L)
2
4
6
8
NO3 (mg/L)
Figure 14: Relation between nitrate concentration and (a) iron and (b) manganese contents for groundwater samples.
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Eighteenth International Water Technology Conference, IWTC18
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24
(a)
Delta NO3-N ‰
Delta NO3-N ‰
24
28
23
16
25
22
24
21
21
(b)
28
23
16
25
22
24
21
21
20
19
19
20
20
20
1
2
3
4
5
6
7
1
8
10
ln NO3
NO3 (mg/L)
Figure 15: Relation between δ15N-NO3- and (a) nitrate concentrations and (b) ln NO3- for groundwater samples
To investigate the direction of contaminant movement and its variation with time, a unit rate of ammonium
concentration is assumed to be applied from a point. The injection is assumed to start at t=0 and continues
indefinitely. The concentration of the contaminant at t<0 is assumed to be zero in the whole region. The simulated
contaminant concentrations for the 5, 10, 15 and 20 years after injection in the fifth layer were calculated for six
observation boreholes in the horizontal direction and other six boreholes in the vertical direction around the source
Fig.(16). The distance between the source the boreholes in each direction are 50, 100, 150m respectively. The
relations between relative concentration and time measured from boreholes are shown in Figs (17.a and b). The
calculated concentration in boreholes no. 1 and 10 which lie only 50m west and north of the injection point increase
to 7.66*10-3 and 7.07*10-3 respectively after 360 days, and reach the maximum relative concentration of 28*10 -3
and 26.14*10-3 respectively after 2160 days (6 years). The analysis of the figures leads to the conclusion that most of
the contaminant flows towards the northern-west direction. This results show that the hydraulic properties and
gradient play the major role on the contaminant transport direction
Figure 17: Positions of the unit source and the considered
boreholes around it.
Figure 16: Variation of relative concentration
around the source.
30
30
Borehole No.1
28
Borehole No.7
28
Borehole No.2
Borehole No.8
Borehole No.3
26
Borehole No.5
24
30.872
Borehole No.9
26
Borehole No.4
Borehole No.10
Borehole No.11
24
Borehole No.6
Borehole No.12
22
22
20
20
18
18
30.868
Source
30.866
16
16
30.87
C/Co * E-3
C/Co * E-3
14
14
12
12
10
10
8
8
6
6
4
4
2
2
0
360
0
360
30.864
30.862
1080
1800
2520
3240 3960 4680
Tim e (days)
5400
6120
6840
7560
30.86
30.858
1080
1800
2520
3240 3960 4680
Tim e (days)
188
5400
6120
6840
7560
30.908
30.91
30.912
30.914
30.916
30.918
30.92
30.922
30.924
30.926
Eighteenth International Water Technology Conference, IWTC18
Sharm ElSheikh, 12-14 March 2015
9 SCENARIOS FOR GROUNDWATER REMEDIATION
A management scenario is suggested to clean up the aquifer at Birma region from ammonium
contamination. The suggested scenario is to use eight extraction wells to pump the contaminated groundwater out of
the aquifer for treatment. The locations of wells are chosen as a diagonal shape toward the northern-west direction,
as shown in Fig. (18), according to the flow direction of contaminant. The measured ammonium concentrations by
hydrochemical analyses are used as the initial condition for the transport model. Prior to running the transport
model, 25 observation boreholes are defined, for which the concentration- time relation can be calculated. The
position of these boreholes are chosen irregularly to cover all Birma region. They are illustrated in Fig.(19). The
proposed total extraction rate for the eight wells is 800 m3/day (100 m3/day for each well), all from layer five. The
final groundwater levels after the simulation period of 7200 days (20 years) and the direction of flow are illustrated
in Fig.(19). The transport model simulation results are presented in Figs.(20a, b, c and d), which illustrate the
contour lines of ammonium concentrations obtained every five years through the simulation period of 20 years.
30.872
23
24
25
w6
30.872
w7
18
30.87
19
21
20
30.87
22
w5
w8
30.868
30.868
14
15
16
17
w4
13
30.866
30.866
30.864
11
10
9
w3
30.864
12
w2
30.862
30.862
1
3
2
4
w1
5
30.86
30.86
8
30.858
7
6
30.908
30.91
30.912
30.914
30.916
30.918
30.92
30.922
30.924
30.858
30.908
30.926
30.91
30.912
30.914
30.916
30.918
30.92
30.922
30.924
30.926
Figure 19: Calculated groundwater levels and
direction
of flow after 7200 days (20 years) of
extraction.
Figure 18: Areal distribution of ammonium
concentrations in mg/L for Birma region based on
chemical analysis.
w6
30.872
w7
30.87
w6
30.872
w5
w7
w8
30.868
30.87
w4
w5
w8
w3
30.866
30.868
w4
w3
30.866
w2
30.864
w2
30.864
30.862
30.862
w1
30.86
w1
30.858
30.86
30.908
30.91
30.912
30.914
30.916
30.918
30.92
30.922
30.858
(20- b)after 3600 days (10 years) of
extraction
(20- a) after 1800 days (5 years) of extraction
30.908
30.91
30.912
30.914
30.916
30.918
30.92
30.922
30.924
30.926
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30.924
30.926
Eighteenth International Water Technology Conference, IWTC18
w6
30.872
Sharm ElSheikh, 12-14 March 2015
w6
30.872
w7
w7
30.87
30.87
w5
w5
w8
w8
30.868
30.868
w4
w3
30.866
w2
30.862
30.862
30.86
30.86
30.858
30.858
30.912
30.914
30.916
30.918
30.92
30.922
w2
30.864
w1
30.91
w3
30.866
30.864
30.908
w4
30.924
w1
30.908
30.926
(20-c) after 5400 days (15 years) of
extraction
30.91
30.912
30.914
30.916
30.918
30.92
30.922
30.924
30.926
(20-d): after 7200 days (20 years) of extraction
Figure 20: Concentration distribution of ammonium-nitrogen in mg/L in Birma
region.
10 CONCLUSIONS
The groundwater in the studied area is quite vulnerable to pollution; deterioration of groundwater indicates
clearly that the human activities caused serious pollution problems. The nitrate concentrations have clear mount
within the area except the north eastern part of the studied area. Ammonium concentrations of groundwater reached
an alarming level and exceeded the drinking water standards (0.5 mg/L). The high concentrations are around Birma
village at the central part of the studied area and at the north eastern region with concentration gradient increases
toward the north boundary outside the area of study. The potential sources of nitrogen compound pollution are:
water from sewage treatment plant used for irrigation, sludge and animal manure, septic tanks, soil nitrogen, and
artificial fertilizers. The analysis of the results leads to the conclusion that most of the contaminant flows towards
the northern-west direction. The results assign that the hydraulic properties and gradient play the major role on the
contaminant transport direction. Stable isotopes of oxygen (δ18O) and hydrogen (δD) were used in this study to
determine the origin of water and to characterize possible mixing of different water sources of water in the
Quaternary aquiferthe. Nitrogen-15 approach achieved the main goal of identifying the potential sources of nitrogen
compound contamination at different locations in the studied area. In this respect, nitrogen isotope ratios (δ15N) in
conjunction with hydrological data and water chemistry were used to help elucidate the sources and fate of
NH
NO
ammonium (
4 ) and nitrate (
3 ) in the Middle Delta region, Egypt. MODFLOW and MT3DMS codes are
employed for solving the 3-D polluted groundwater problem in the study area and for predicting the concentration of
pollution at several time intervals. In the present study, MT3DMS was utilized to simulate ammonium contaminant
variation in Birma region. Three verifications for modelling codes are performed and good agreements between
results of present study and previous studies are attained. A unit rate of ammonium concentration is assumed to be
applied from a point. The injection is assumed to start at t=0 and continues indefinitely. The concentration of the
contaminant at t<0 is assumed to be zero in the whole region. The simulated contaminant concentrations for the 5,
10, 15 and 20 years after injection are presented.
NH
The δ15N results indicated that the relatively depleted δ15N4 values (±2‰) are mainly found in the
central and western part of the studied area. These areas are affected by the application of synthetic fertilizers. By
NH
contrast, the north and south-eastern areas have δ15N4 values >+4‰ indicating soil organic nitrogen or
mixing with raw sewage (untreated domestic effluents) injected in the aquifer, particularly in the populated zones.
NO
The inverse correlation between nitrate concentrations and δ15N3 values indicates that a clear redox barrier is
present in the north-eastern area, accompanied by the appearance of Mn 2+ and Fe2+ ions and disappearance of nitrate,
with a very distinct enrichment in δ15N (δ15N-
NO3 >+20‰) of the remaining NO3 (denitrification process).
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Eighteenth International Water Technology Conference, IWTC18
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A mitigation scenario is suggested to clean up the Birma region. The remediation scheme assumes
dewatering system through eight extraction wells to pump the contaminated groundwater out of the aquifer for
treatment. The locations of wells were chosen toward the flow direction of contaminant. . The procedure of solution
proved to be efficient in minimizing groundwater pollution. Moreover, it proved to be applicable and can be
generalized for a wide class of regions that suffer from groundwater contamination phenomenon.
REFERENCES
Zaghloul M.G., (1958): "Flow Distribution Through Groundwater Aquifer of The Nile Delta".
M.Sc. Thesis, Faculty. of Engineering., Alex. University.
Zaghloul Z.M., Abdallah A.M., Serag El-Din H., And Hefny K., (1984): "Ground-water Pollution
In The Nile Delta Area, Egypt". J. Geol., Vol. 28, No.1, pp. 131-140.
Darwish, M. H. (1994) “Effect of Probable Hydrological Changes on The Nile Delta
Aquifer System ”. M.Sc. Thesis, Faculty of Engineering, Cairo University.
Awad, M.A., Farid, M. S. and Hamza, M. S. (1994) “Studies on the recharge of the Aquifer
Systems in the Southern Portion of the Nile Delta using Radio Isotops and Hydrochemistry ”. Isotope
& Rad. Res., 16, 1, 17-25.
Awad, M.A., Sadek, M.A. and Salem, W.M.(1999): “Use of mass balance and statistical
correlation for geochemical and isotopic investigation of the groundwater in The Quaternary
Aquifer of The Nile Delta, Egypt ”. Arab Journal of Nuclear Sciences and Applications,
32(1), pp.43-58.
Habib, M.M. (1996): “Hydrogeological Studies on El-Gharbia Governorate, Central Nile
Delta, Egypt”. M.Sc.Thesis, Geology Department , Faculty of Science, Tanta University.
Gondia, W. M. K. (1995): “Numerical Simulation of Water Policies in Middle Nile
Delta”. M.Sc. Thesis, Faculty of Engineering, Cairo University.
Abd El-bary, M.H. (2004): “Sedimentological, Geochemical and Hydrogeological
Characteristic of The Central Nile Aquifer, Egypt”. M.Sc. Thesis, Geology Department ,
Faculty of Science, Tanta University.
Farid M.S., (1980): "Nile Delta Groundwater Study". M.Sc. Thesis, Faculty of Engineering, Cairo
University.
Farid, M.S. (1985): “Management of Groundwater System in The Nile Delta”. Ph. D.
Thesis, Faculty of Engineering, Cairo University.
Daifullah, A. M. et. Al (2003) “Evalution of some heavy metals in water, sediment and
fish samples from River Nile (Kafr El-Zyat City), Egypt: A treatment approach”. African
Journal of Environmental Assessment and Management. 6(1): pp 16-31, Jun.
(http://www.Ajeam-ragee.org/getdoc.asp?fpath
2003 p16-31.doc).
=c:/domains/ajeamragee.org/db/vol6
Goamea, O.M. (2000): “Behavior of The Transition Zone in The Nile Delta Aquifer
Under Different Pumping Schemes”. Ph. D. Thesis, Faculty of Engineering, Cairo University.
RIGW/IWACO, (1990): "Development and Management of Groundwater Resources in
191
june
Eighteenth International Water Technology Conference, IWTC18
Sharm ElSheikh, 12-14 March 2015
the Nile Valley and Delta: Assessment of Groundwater Pollution from Agricultural
Activities". Research Institute for Groundwater, Kanater El-Khairia, Egypt.
El Molla, A. M., Dawoud, M. A., Hassan, M. S., Sayed Ahmed, H. A. and Mohamed, R. F.
(2005)” Integrated Management Of Water Resources In Western Nile Delta, 1-Building And
Calibrating The Groundwater Model” Fourth International Symposium on Environmental
Hydrology,2005, ASCE-EG, Cairo, Egypt.
Zeydan, B. A. (2005) “The Nile Delta in a Global Vision”. 9th International Water Technology
Conference, IWTC-IX.
Harr, M.E. (1962): “Groundwater and Seepage”. Mc Graw Hill Book Co. Inc. New York.
Bear, J. (1987) “Modeling Groundwater Flow and Pollution”. D. Reidel Publishing
Company, Dordrecht.
Chunmiao, Z. and Patrick, W. (1999) “A Moldular Three Dimensional Multispecies
Transport Model”. United States Army Corps of Engineers, Washington, DC20314-1000,
November, 1999.
Sharukh, M. (2001): “Modeling the Effect of Chemical Fertilizers on Groundwater
Quality in the Nile Valley Aquifer, Egypt”, Groundwater, Vol.39, No.1, pp.59-67.
Zeydan, B.A. (2004) ”Groundwater Quality Studies In The 21st Century” Al-Azhar Engineering
Eighth International Conference, December 24 - 27, C155.
Wang, P. (2005) “A General Approach To Advective-Dispersive Transport With
Multirate Mass Transfer”. Advances in Water Resources, Vol. 28, pp.33-42, 2005.
Atta, S. A., Sharaky, A. M., El Hassanein, A. S. and Khallaf, K. M. A. (2005) “Salinization Of
The Groundwater In The Coastal Shallow Aquifer, Northwestern Nile Delta, Egypt” First
International Conference on the Geology of Tethys, Cairo University, Novmber, 2005, P. 151-166.
Sharaky, A. M., Atta, S. A., El Hassanein, A. S. and Khallaf, K. M. A. (2007) “Hydrogeochemistry of Groundwater In The Western Nile Delta Aquifers, Egypt” 2nd International
Conference on the Geology of Tethys, 19-21 March, 2007, Cairo University.
Salem, M. I. (2006) “Evaluation of Groundwater Pollution from Agricultural Practices in The
Western Part of Nile Delta”. Ph. D.Thesis, Department of Agricultural Science, Institute of
Environmental Studies and Research, Ain Shams University.
Ahmed, M.A., Aly, A.I.M. and Ghoraba, S.M. (2009)” Application of Isotopic and
Hydrochemical Tracers for Investigation of Nitrogen Pollution Sources of Surface Water and
Groundwater in the Middle Delta, Egypt” Isotope and Radiation Research Journal Vol. 41(4), pp.
1627-1647
El-Fakharany, M. A. and Mansour, N. M. (2009) “Assessment of Water Resources Quality at the
Southeastern Part of the Nile Delta, Egypt” The International Conference on Water Conservation in
Arid Regions, 12-14 October 2009.
192
Eighteenth International Water Technology Conference, IWTC18
Sharm ElSheikh, 12-14 March 2015
Ghoraba, S. M. (2009) “Groundwater Quality Management in the Middle Delta Utilizing
Environmental Isotopes”, PhD. Thesis submitted for Civil Engineering (Irrigation and Hydraulics
Engineering), Faculty of Engineering, Tanta University, Egypt.
Ghoraba, S.M., Zeydan, B.A., Rashwan, I.M.H. (2012)”Solute Transport Modeling of the
Groundwater for the Quaternary Aquifer Quality Management in Middle Delta, Egypt”, Alexandria
Engineering Journal. AEJ-D-12-00102.
Hussin, F.M. and Mousa, L. (2012) “Water management in the System of the River Nile in Egypt
assisted by isotopic and geochemical data” IS.RIVERS 2012, C4 – EAUX SOUTERRAINES /
GROUNDWATERS.
Lo Russo, S. and Taddia, G. (2012) ” Aquifer Vulnerability Assessment and Wellhead Protection
Areas to Prevent Groundwater Contamination in Agricultural Areas: An Integrated Approach”,
Journal of Water Resource and Protection, 2012, 4, 674-685 doi:10.4236/jwarp.2012.48078 Published
Online August 2012 (http://www.SciRP.org/journal/jwarp).
Kendall, C. and Aravena, R. (2000) “ Nitrate isotopes in groundwater systems. In:
Environmental Tracers in Subsurface Hydrology (Cook, P.G. & Herczeg, A.L., Eds.) Kluwer
Academic, Boston, 261-297.
Clark, J.D. and Fritz, P. (1997) “Environmental Isotopes in Hydrogeology”. Lewis
Publishers, New York.
Chiang, W.H. and Kinzelbach, W. (1998) “Processing MODFLOW ”. A Simulation System for
Modeling Groundwater Flow and Pollution, Humburg. Zurich.
Shaltout, F.M. (1996): “Contamination Of Groundwater By Waste Waters” PhD Thesis, Faculty
of Engineering, Mataria, Helwan University, Egypt.
Oldenburg, C. M. & Pruess, K., (1995) “Dispersive Transport Dynamics In A Strongly
Coupled Groundwater-Brine System” Water Resources Research, Vol.31, pp.289-302.
193