الفهرس 
Chapter1: IntroductionOnly 14 pages are availabe for public view
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Abstract
The aim of this study is to evaluate the performance of three surface water
treatment plants using different filtration technologies.
These systems were Traditional filtration system, Direct gravity filtration
system with a declining rate and Pressurized filter system process. These are
represented by Main Shebin El Kom WTP (800 l/s), Mit Mosa WTP (120 l/s) and
Pressurized filter system process used in El Dalatoun WTP (30 l/s) respectively in
Menofia Governorate.
The performance evaluation is based on variations in turbidity, total
dissolved solids (TDS) and total solids (TS) as well as micro-organisms counts in
raw and filtered water as a scientific comparison. It is also based on the difference
in the components of each system and its flow line diagram as an engineering
comparison in addition to an economic comparison between the studied treatment
processes with different filtration systems following an evaluation of collected
data along four years from existing water treatment plants (WTPs).
Economic comparison between different filtration systems considered
several factors as electrical power consumption, required areas, operation and
maintenance cost, consumption of chemicals (chlorine and alum), backwashing
frequency as a measure of media consumption and construction cost, this is
guided by value engineering as to identify function reliability at the least overall
cost.
The technical comparison showed a high efficiency for all studied water
treatment systems using various filtration processes for removal of contaminants
as microorganisms as well as turbidity to the required levels.
Overall efficiency for Shebin El Kom, Mit Mosa & El Dalatoun WTPs
were 97.29%, 96.75% & 95.51% (level complying with treated water quality
criteria) respectively in terms of turbidity removal.
The three studied water treatment plants with the different filtration
processes also were all successful (100%) in the removal of microorganisms.
A tiny increase in TDS may be noted possibly due to the effect of prechlorination
in destroying any microbial films opting to flourish within the
filtration media and thus release of such minor amounts. Also the effect of
chemicals addition as part of the process for treatment is one important factor for
the consistency of such minor increase in TDS.
It is to note that these plants have various capacities / flows and the
economic study opted to normalize the comparison factors (as chemicals and
electric consumption and construction cost among others) per selected unit of
produced (treated) water in order to apply economic comparisons. In order to cope
with a reasonable assumption for economic evaluation, two sets of factors were
considered pertaining to Capital Cost (construction cost and land cost) and
Operation Cost (consumables from alum & chlorine, electric power consumption,
cost of operators and backwash frequency).
It is assumed that both construction cost and operation cost has similar
importance thus assigning 50% of weight to each of them as the construction of the
new facilities requires an upfront investment, while systems with considerable
requirements for operation would require an investment equal to capital cost on the
long run. Moreover, the five factors affecting operation cost were looked at equally
while the construction cost was considered as 80% of the Capital Cost while the
land area price would be assigned the remaining 20% weight of this category.
A sensitivity analysis was conducted by further reducing and increasing the
effect (weights) of construction cost giving alternative effects of operation cost to
be maximum and minimum consequently; the results remained with the same rank
though the difference in collective scores which further highlights the importance
of direct filtration process for surface water where raw water quality enables such
application.
The main conclusions of results revealed similar performance in removal of
turbidity, microorganisms and TS concentration through various filtration systems.
Since the construction of the new facilities requires an upfront investment, it is
worth noting that the cost indicator / (50 years for civil work and 15 years for mechanical and electrical works’ life time) for gravity “conventional” filtration,
direct filtration and pressurized filtration are 01.03, 00.47 & 01.31 (EGP)/ m3 of
treated water respectively in terms of construction cost under the studied
conditions with taking into consideration inflation occurred from 2015: 2018 in the
local currency.
Although increasing doses of alum in conventional filtration system that is
considered as defects (cost) but the presence of Clari-flocculators before
conventional filtration system reduced the level of turbidity before filters to 25%
of its value at the inlet of WTP.
Direct filtration system with a declining rate was considered the most
economic in operation. The results also indicated that conventional filtration
system stands in an intermediate position in terms of economic comparisons.
Although pressurized compact filtration system recorded efficiencies same as other
systems in terms of removal of turbidity and microorganisms, the system was the
least favored in economical comparisons under the studied conditions (e.g. flow,
water quality, consumables). Based on the findings, the study presented a set of
scientific and practical recommendations.