الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Significant scientific and technological developments have opened the
way for several treatment processes that are able to comply with a wide
range of discharge standards. However, the pure availability of a technology
is not by itself sufficient, because it should be cost-effective, appropriate to
the local conditions and affordable.
In Egypt’s small communities there is an increasing need for low cost,
and small area process for treating wastewater. The operation of each
method and maintenance must be within the capability of developing
country. Thus the idea of constructing a cost-effective high efficiency and
small area treatment facility is very demanding. A comprehensive study was
executed focusing on the efficiency and economic aspects of different
wastewater treatment technologies in Egypt.
In this context, it is believed that this study is of great relevance to the
wastewater treatment sector, since it evaluates the actual behavior of more
than 25 full-scale wastewater treatment plants. Those plants are in operation
in four governorates Kafr El-Sheikh, Al-Gharbia, El-Fayoum, and El-
Sharqia in Egypt. This study provides information on the performance of
eight treatment technologies in terms of effluent quality and removal
efficiency. The discharges of these studied plants ranged between 978m3/d
and 6000m3/d. also, the results obtained for these technologies are likely to
be representative for other developing regions. The treatment technologies
most widely used in slightly different climate regions are evaluated here.
The observed results of effluent concentrations and removal efficiencies of
wastewater are biochemical oxygen demand (BOD), chemical oxygen
demand (COD), total suspended solids (TSS). These concentrations are
compared with the typical expected performance reported in the literature.
The treatment technologies selected for the study are oxidation ditches,
oxidation ponds, aerated lagoons, extended aeration, conventional aeration,
rotating biological contactors (RBC), upward-flow anaerobic sludge blanket
Reactor (UASB), and compact units.
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Performance evaluation between the last mentioned wastewater
treatment technologies (WWTTs) was introduced in this study and a great
variability was noticed in the effluent concentrations and in the removal
efficiencies, considering the analyzed parameters and all treatment
technologies.
The performance of extended aeration technology was the best one
between the all studied technologies. It could be applied for the discharges
ranged between 2000 and 6000m3/d and serve a population ranged between
10,000 and 30,000capita. It secured BOD removal efficiency equal to
95.34%, COD removal efficiency equal to 94.08%, and TSS removal
efficiency equal to 91.57%.This powerful performance in removing COD
and BOD owing to the long solid retention times ranges from 24-30hrs and
the wide range of sludge loading rate (SLR, variable sludge age), through
variable sludge wasting program, the organic pollutants (COD and BOD)
could be utilized by the microbial community at long sludge ages.
The oxidation ditch technology applied in Kafr El-sheikh governorate has
been proved a performance higher than the literature for removing different
contaminants. The average removal efficiencies of BOD, COD, and TSS
were 95.02%, 93.98%, and 91.24 %, respectively. This technology gives an
excellent efficiency for the discharges ranged between 1000m3/d and
6000m3/d and it serves a population ranged between 5,000 and 30,000capita.
The performance of the aerated lagoons was so good for its removal
efficiencies. The average removal efficiencies of BOD, COD, and TSS were
88.84%, 92.04%, and 90.62%, respectively. It is more suitable for the
villages with wide lands and plenty of electricity. The RBCs showed a
moderate performance in terms of BOD, COD, and TSS removal, with
significant removal percentages equal to 88.78%, 89.23%, and 87.21%,
respectively. The discharges of the studied plants in this technology ranged
between 3000m3/d and 6000m3/d. The total removal efficiencies of compact
unit technology in terms of BOD, COD, and TSS were 84.98%, 85.06%, and
81.07%, respectively. It fits the very small discharges produced from resorts
and rests and small residential buildings. It is used in packaged plants. The
performance presented by the conventional aeration plants, considering
organic matter removal, was significantly unexpected among all the
evaluated systems. This system recorded removal efficiencies for BOD
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equal to 80.40%, COD equal to 83.19%, and 72.95% for TSS removal
efficiency. These values were lower than the limits. The UASB reactors
technology showed low BOD and COD removal efficiencies and a poor
performance regarding TSS. The performance achieved by the UASB
reactors was equal to 72.41% for BOD average removal efficiency, 72.33%
for COD, and 47.78% for TSS average removal efficiency. The oxidation
ponds have achieved the least performance among all the studied
technologies with a removal efficiency values equal to 59.99% for BOD,
74.17% for COD, and 50.13% for TSS. It is the simplest system for the
wastewater treatment because its operation and maintenance is not
complicated and low construction cost, low power consumption. It is
particularly suited for the villages of high-temperature, high-strength
wastewater, and with plenty of land and surrounded by desert like El-
Fayoum and Upper Egypt villages. It achieved the highest score of cost
which includes electricity consumption and labor productivity.
Regarding the economical evaluating for the studied WWTTs. the oxidation
ponds systems are the most appropriate alternative at the least cost in the
presence of regular maintenance and cleaning for the ponds, while the
oxidation ditch is the most expensive system.
CHAPTER (1) (INTRODUCTION)
1
CHAPTER 1
INTRODUCTION
1.1 General
Egypt is facing a great challenge dealing with wastewater problems
due to the growth of population and consequently the increase of
wastewater production. Technological progress allowed the realization of
advanced wastewater treatment systems, but the cost of these advanced and
specialized systems cannot be afforded.
The process of disposal of wastewater in Egyptian villages represents a
dangerous challenge to environment and public health. In spite of the fact
that at least 85% of rural-residential buildings have some types of sanitary
facility. A limited percentage of villages have recent facilities for safe
collection and wastewater treatment. The main cause of water pollution,
hygienic and environmental hazards in small villages in Egypt is
discharging of most wastewater to agricultural drains and sometimes to
canals with or without treatment. So their use becomes unsafe. The number
of rural wastewater treatment plants in operation may not exceed 500, while
the total number of villages exceeds 5,500, so the number of desired sewer
systems in villages is far greater than the number of established wastewater
treatment plants (HCWW, 2008).
1.2 Scope of the Study
The research represents a comparative study between eight WWTTs. at
many small villages lied in four governorates, which namely are Kafr Elsheikh,
El-Gharbia, El-Fayoum, and El-Sharqia in Egypt. Then an
assessment for .