This document provides an outline for a master's program on water and environmental science. It discusses definitions of wastewater and its characteristics. It describes the global extent of water usage and economic and social benefits and risks of wastewater treatment. It outlines conventional wastewater treatment processes including preliminary, primary, secondary, tertiary, and disinfection. It provides information on wastewater treatment in the Gaza Strip, including details on four treatment plants. It also mentions nitrate pollution of Gaza's groundwater aquifer.

1. Wastewater Treatment
Al-Azhar University-Gaza
Master Program of Water and Environmental
Science

2. Outline
Definitions:
Characteristics of wastewaters:
The global extent
Economic benefits and risks of Wastewater treatment
Economic Benefits
Economic risks
Social and health benefits and risks
Environmental benefits and risks
Conventional wastewater treatment processes:
Preliminary treatment
Primary treatment
Secondary treatment
Tertiary and/or advanced treatment
Disinfection

3. Outline
Waste water treatment in the Gaza Strip
Wastewater Treatment Plants in the Gaza Strip
Beit Lahiya Treatment Plant
Sheikh Ajleen Treatment Plant
Rafah Treatment Plant
Khanyounis Temporary Treatment Plant
Nitrate pollution of ground water in Gaza Strip aquifer
References

4. Definition:
Waste water:
Sewage water is known as the quantities of water
used by the human population, whether for domestic
or industrial purposes. It contains both dissolved and
solid contaminants. It is generally collected in
sewers that all together compose the sewage system.

5. Definition:
Wastewater: Urban wastewater is usually a
combination of one or more of the following which
makes it polluted water:
Domestic effluent consisting of blackwater (excreta,
urine and faecal sludge, i.e. toilet wastewater) and greywater (kitchen and bathing wastewater)
Water
from commercial establishments and
institutions, including hospitals
Industrial effluent where present
Storm-water and other urban run-off.

6. Treated wastewater: Is wastewater that has been
processed through a wastewater treatment plant up to
certain standards in order to reduce its pollution or
health hazard; if this is not fulfilled; the wastewater
is considered at best as partially treated.
Reclaimed wastewater: or recycled water is treated
wastewater that can officially be used under
controlled conditions for beneficial purposes such as
irrigation

7. Characteristics of wastewaters:
Municipal wastewater is mainly comprised of water
(99.9%) together with relatively small concentrations
of suspended and dissolved organic (carbohydrates,
lignin, fats, soaps, synthetic detergents, proteins…)
and inorganic solids
Wastewater = clean water supply + solids

8. Table1:Majour constituents of typical domestic wastewater
Constituent
Total solids
Dissolved solids (TDS)1
Suspended solids
Nitrogen (as N)
Phosphorus (as P)
Chloride1
Alkalinity (as CaCO3)
Grease
BOD52
Strong
1200
850
350
85
20
100
200
150
300
Concentration, mg/l
Medium
700
500
200
40
10
50
100
100
200
Weak
350
250
100
20
6
30
50
50
100
In arid and semi-arid countries, water use is often fairly low and
sewage tends to be very strong

9. Table 2: Average composition of wastewater in Amman,
Jordan
Constituent
Dissolved solids (TDS)
Suspended solids
Nitrogen (as N)
Phosphorus (as P)
Alkalinity (as CaCO3)
Sulphate (as SO4)
BOD5
COD1
TOC1
Concentration mg/l
1170
900
150
25
850
90
770
1830
220

10. Table 3: Chemical composition of wastewater in Alexandria and Giza , Egypt
Constituent
EC
pH
SAR
Na2+
Ca2+
Mg
K+
ClSO42CO3
HCO3NH4+
NO3
P
Mn
Cu
Alexandria
Unit
Concentration
dS/m
3.10
7.80
9.30
me/l
24.60
me/I
1.50
me/I
3.20
me/I
1.80
me/I
62.00
me/I
35.00
me/I
1.10
me/I
6.60
mg/l
2.50
mg/l
10.10
mg/l
8.50
mg/l
0.20
mg/l
1.10
Unit
dS/m
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
Giza
Concentration
1.7
7.1
2.8
205
128
96
35
320
138
0.7
0.4

11. Table 4: Possible levels of pathogens in wastewater
Type of pathogen
Viruses:
Bacteria:
Enteroviruses
Pathogenic E. coli
Salmonella spp.
Shigella spp.
Vibrio cholerae
Protozoa:
Helminths:
Entamoeba histolytica
Ascaris Lumbricoides
Hookworms4
Schistosoma mansoni
Taenia saginata
Trichuris trichiura
Possible concentration
per litre in municipal
wastewater1
5000
?
7000
7000
`1000
4500
600
32
1
10
120

12. The global extent
Earth contains an estimated 1351 million cubic km of
water, Only 0.003 % of this is classified as fresh water.
The common needs for water fall into the following
categories:
Drinking water
Agriculture
Personal hygiene and public sanitation
Domestic uses (food preparation, cleaning, outdoor
uses)

13. The common needs for water
 Commerce and services
 Industry
 Recreation and tourism
 Environmental and ecological maintenance,
conservation and protection

14. Table 5: Threshold values used to characterize water stress
within a region
Characteristic
Threshold
Water stress
<1 700
Chronic water
scarcity
<1 000
Situation
Water Scarcity Index, m3/ capita /yr
The region begins to experience water stress and the economy or
human health may be harmed
The region experiences frequent water supply problems, both
short
and long-term
Absolute water <500
stress
The region completes its water supply by desalting seawater,
overexploiting aquifers or performing unplanned water reuse
Minimum
survival level
Water supply for domestic and commercial uses is compromised,
since the total availability is not enough to fulfil demand for all
uses (municipal, agricultural and industrial)
<100

17. Economic benefits and risks of Wastewater treatment
Economic Benefits:
Serve as a more dependable water source.
Enhance urban, rural and coastal landscapes, thereby increasing
employment and local economy through tourism
Be substituted for freshwater or potable water to meet specific
needs and purposes (such as irrigation, toilet flushing, cooling...)
Reduction or elimination of fertilizer application.
In many applications, treated wastewater reuse is less costly than using
freshwater, pumping deep groundwater, importing water, building dams
or seawater desalination

18. Economic risks
 The




economic impact of public health epidemics or
environmental pollution
High distribution and storage costs due to the distance between
supply and demand location
Weak economic justification when water prices do not cover the
true cost.
The local market demand for treated wastewater is not clearly
defined and agreed
Negative branding of treated wastewater reuse by the general
public.

19. Social and health benefits and risks
Social and health benefits
Helping to achieve Millennium Development Goals (MDG)
through increasing water availability and poverty reduction
Contributes to food security, better nutrition and sustains
agricultural employment for many households
Increased quality of life, well being and health through attractive
irrigated landscapes in parks and sports facilities in rich and poor
communities

20. Social and health risks
 Threat to public health, especially if illegal and unhealthy
wastewater reuse practice expands due to water scarcity.
 Social tensions in case of non-acceptance:

21. Environmental benefits
 Treated wastewater reuse allows for the conservation and





rational allocation of freshwater resources, particularly in areas
under water stress.
Reduces the amount of discharges and therefore the level of
nutrients or other pollutants entering waterways
Provides a mitigation solution to climate change through the
reduction in green house gas by using less energy for
wastewater management rather than importing water, pumping
deep groundwater, seawater desalination or exporting
wastewater
Reduces the need for chemical fertilizers
Sludge can be used as soil conditioners
Treated wastewater can be used to recharge aquifers.

22. Environmental risks
 Hazardous or toxic waste and salts from industry can reduce
the quality of the wastewater and risk public health
 Reused treated wastewater may constitute an additional
pressure onto the aquatic environment

23. Conventional wastewater treatment processes
 Conventional wastewater treatment consists of a combination of
physical, chemical, and biological processes and operations to
remove solids, organic matter and, sometimes, nutrients from
wastewater
 General terms used to describe different degrees of wastewater
treatment are, preliminary, primary, secondary, and tertiary
and/or advanced wastewater treatment

24. Preliminary treatment
Preliminary treatment:
screening and grit removal to remove coarse solid and other large
materials often found in raw wastewater. It includes coarse
screening and grit removal.

25. Primary treatment:
Primary treatment: sedimentation – simple settlement of solid
material in a primary settling tank. Solid particles settle at the
bottom, and oils and greases rise to the top. This material is
removed as sludge, for separate treatment.
Approximately 25-50% of the incoming BOD5, 50-70% of the
total suspended solids (SS), and 65% of the oil and grease are
removed during primary treatment
Some organic nitrogen, organic phosphorus, and heavy metals
associated with solids are also removed during primary
sedimentation but colloidal and dissolved constituents are not
removed.

26. Table 6: Quality for raw wastewater and primary
effluent at selected treatment plants in California
Quality parameters (mg/l,
except as otherwise
indicated)
City of Davis
Raw
Primary
wastewater effluent
San Diego
Raw
Primary
wastewater
effluent
Los Angeles County Joint Plant
Raw
Primary effluent
wastewater
BOD5
112
73
184
134
-
204
Total organic carbon
63.8
40.6
64.8
52.3
-
-
Suspended solids
Total nitrogen
NH3-N
NO-N
Org-N
Total phosphorus
185
43.4
35.6
0
7.8
-
72
34.7
26.2
0
8.5
7.5
200
21.0
-
109
20.0
10.2
-
219
39.5
14.9
11.2
Ortho-P
-
7.5
11.2
pH (unit)
Cations:
Ca
Mg
Na
K
Anions:
SO4
7.7
-
7.3
7.3
-
-
-
-
-
-
78.8
25.6
357
19
359
19
Cl
Electrical conductivity, dS/m
-
-
160
270
-
120
397
2.52
2.34
2.19
Total dissolved solids
-
-
Soluble sodium percentage, %
-
Sodium adsorption ratio
-
-
-
-
8.85
6.8
Boron (B)
Alkalinity (CaCO3)
-
-
-
-
1.68
322
1.5
332
Hardness (CaCO3)
-
829
821
-
-
-
1404
1406
70.3
265

27. Secondary treatment
 Wastewater from primary treatment flows into an aeration tank,
to which micro-organisms are added to consume the remaining
organic matter.
 Following aeration, the mixture is clarified. The residue is
removed as sludge, for separate treatment and disposal.
 Several aerobic biological processes are used for secondary
treatment differing primarily in the manner in which oxygen is
supplied to the microorganisms and in the rate at which
organisms metabolize the organic matter.
 High-rate biological treatment processes, in combination with
primary sedimentation, typically remove 85 % of the BOD5 and
SS originally present in the raw wastewater and some of the
heavy metals.

28. Activated Sludge

29. Trickling Filters

30. Rotating Biological Contactors

31. Table7: Quality of secondary effluent at selected wastewater
treatment plant in California
Quality parameter (mg/I
except as otherwise
indicated)
Plant location
Trickling filters
Activated sludge
Chino Basin
MWD (No. 1)
Chino Basin MWD
(No. 2)
Santa Rosa Laguna
Montecito Sanitary
District
BOD5
21
8
-
11
COD
-
-
27
-
18
25
0.7
-
26
11
19
-
10
8
1.7
12.5
3.4
-
13
1.4
5
7.6
43
12
83
17
55
18
102
20
41
18
94
11
82
33
-
293
85
81
476
2.9
0.7
156
192
143
90
591
3.1
0.6
200
165
66
121
484
3.9
0.6
175
192
245
1.39
940
3.7
0.7
226
Suspended solids
Total nitrogen
NH3-N
NO3-N
Org-N
Total phosphorus
Ortho-P
pH (unit)
Cations:
Ca
Mg
Na
K
Anions:
HCO3
SO4
Cl
Electrical conductivity dS/m
Total dissolved solids
Sodium adsorption ratio
Boron (B)
Alkalinity (CaCO3)
Total Hardness (CaCO3)

32. Tertiary and/or advanced treatment
 It is employed when specific wastewater constituents
which cannot be removed by secondary treatment must
be removed
 Individual treatment processes are necessary to
remove nitrogen, phosphorus, additional suspended
solids, refractory organics, heavy metals and dissolved
solids
 Advanced treatment processes are sometimes
combined with primary or secondary treatment

33. Disinfection
 Involves using of chlorine solution injection, ozone and




ultra violet (UV)
Chlorine solution is the most common disinfectant used in
wastewater treatment
The bactericidal effects of chlorine depends on pH, contact
time, organic content, and effluent temperature.
Dosages of 5-15 mg/l are common, with contact time of 30
minutes
To meet advanced wastewater treatment requirements, a
chlorine contact time of as long as 120 minutes is
sometimes required for specific irrigation uses of reclaimed
wastewater

34. Waste water treatment in Gaza Strip
Table 8: waste water networks coverage in Gaza strip governorates
Governorate
Covering %
North
% 80
Gaza
% 90
Middle Area
% 70
Khanyouness
% 40
Rafah
% 70
The overall ratio
wastewater coverage
% 70.7

35. Middle area
 There is currently no wastewater treatment plant in this
Governorate.
 Most raw sewage is collected in a concrete pipe through
Salah Aldeen Road and slopes to Wadi Gaza, and then
flows to the sea.
 The flow rate of untreated sewage into the sea is about
10,000 m3/day.

36. Wastewater Treatment Plants in the Gaza Strip
 The quantity of wastewater produced in Gaza strip is more
than 30 million cubic meter per year. The BOD5 level is
about 600 mg/l, which means that the wastewater in Gaza
Strip is strong, and that due to the low portion of fresh
water for citizens (70-90 liters per capita / day).
 In the Gaza Strip, there are three main treatment plants and
one temporary plant for collecting and treating wastewater
 The current treatment plants still do not meet the standards
of treating wastewater in Gaza

37. Beit Lahiya wastewater treatment plant
 Beit Lahiya treatment plant was established in 1974 by the
Israeli Civil Administration in the town of Beit Lahiya in the
northern area of the Gaza Strip
 The aim behind the plant establishment was to re-use the
treated wastewater for agricultural purposes but this aim was
not achieved
 Current inflows to the plant are greater than 17,000 m3/day,
beyond plant capacity
 The partially treated wastewater is pumped to the northern
and eastern infiltration lagoons in the same governorate.

38. Sheikh Ajleen Treatment Plant
 The plant was established in 1979 with an infiltration basin next





to it
In 1986 the (UNDP) established another two infiltration basin to
develop the plant.
In1996 the Municipality of Gaza and UNRWA developed it in
order to recharge 12,000 cubic meters per day.
In 1998 the plant was rehabilitated and its capacity was enlarged
to recharge 35,000 cubic meters per day.
In 2009 the water pumped to the plant increased to 60,000 cubic
meters per day and this exceeds the plant capacity
After the year 2005 many people seized the plant infiltration
basins and turned them into agricultural lands, thus the semitreated WW was pumped to the sea

39. Rafah Treatment Plant
 Rafah treatment plant was established in 1989 near in Tel Al




Sultan in the western of Rafah
It consists of a lagoon with four aerators
The capacity of the treatment plant is 4,000 cubic meters only per
day.
the current flow is up to 8,500 m3/day
The treatment of the plant is inadequate (effluent characteristics
are BOD 300ppm, COD 550ppm, and TSS 250ppm)
virtually untreated sewage is being discharged to the sea

40. Khanyounis Temporary Treatment Plant
 In late 2007, CMWU gradually established wastewater lagoons




in Almawassi area where the last one was established in early
2009
Those lagoons were established to pump the water from Hai ElAmal lagoons
Hai El-Amal lagoons were established in year 2003 to collect
and infiltrate storm water of khanyounis, but due to the frequent
closure and the Israeli harassments during the establishment of
project the project was suspended
deteriorated infrastructure changed the lagoons into an outlet for
the wastewater pumped from the whole district
The current flow rate is about 5,000 m3/day

41. Nitrate pollution of ground water in the Gaza Strip
aquifer
 The groundwater aquifer of Gaza is extremely susceptible to
surface-derived contamination because of the high permeability
of sands and gravels that compose the soil profile of Gaza.
 Almost 90% of the groundwater wells of the Gaza Strip sampled
between 2001 and 2007 showed NO3 – concentrations two to
eight times higher than the WHO standards.
 NO3 − in the groundwater of the Gaza Strip occurred as a result
of NO3 − leaching from irrigation, wastewater septic tanks,
sewage sludge, animal manure and synthetic fertilizers.

42. Nitrate pollution of ground water
 Recent observations revealed a high positive correlation
between the concentrations of NO3 − (N80 mg/l) in
groundwater of the Gaza Strip and the occurrence of
methemoglobinemia in babies younger than six months of age
 Among 640 babies tested in Gaza, 50% showed signs of
methemoglobinemia in their blood samples.

44. References
1.
2.
3.
4.
5.
Abdel Fattah N. Abd Rabou .2011. Environmental Impacts Associated with
the Beit Lahia Wastewater Treatment Plant, North Gaza Strip, Palestine:
Middle-East Journal of Scientific Research 7 (5): 746-757, 2011. ISSN
1990-9233
B. H. Shomar, G. Muller, and A. Yahya, “Potential use of treated
wastewater and sludge in the agricultural sector of the Gaza Strip”, Clean
Techn Environ Policy, Vol. 6, 2004.
Baalousha H (2008) Analysis of nitrate occurrence and distribution in
groundwater in the Gaza Strip using major ion chemistry. Global NEST J
10:337–349
Basem Shomara, Karsten Osenbrückb and Alfred Yahyaa. (2008). Elevated
nitrate levels in the groundwater of the Gaza Strip: Distribution and
sources. SCIENCE OF THE TOTAL ENVIRONMENT 398 164–174.
CMWU, 2010,Annual Report on Water Status in the Gaza Strip,

45. References
6.
7.
8.
FAO (1992) Wastewater treatment and use in agriculture - FAO irrigation
and drainage paper 47. FAO, Rome.
Fareed Ashour1, Bashar Ashour2, Marek Komarzynski3, Yasser Nassar4,
Mary Kudla5, Najla Shawa6 and Graham Henderson6 , 2009, A brief
outline of the sewage infrastructure and public health risks in the Gaza Strip
for the World Health Organisation.
The Economics of Wastewater Use in Agriculture. In: FAO Water Reports,
35/ FAO, James Winpenny, et,al. (2010). Rome, Italy, Electronic Publishing
Policy and Support Branch Communication Division. (ISBN: 978-92-5106578-5, ISSN: 1020-1203).

46.  mrbakr1991@gmail.com