الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Sharki Water Treatment Plant (also called Bab Sharki) is AWCO’S oldest WTP. It was constructed in Alexandria since 1860. It has a designed rated capacity of 620000 m3/day, however, present flow as reported by plant operators is 350000 – 370000 m3/day at winter, and reaches to be 440000 m3/day at summer time. Since 2001 Sharki WTP does not operate at its full capacity because there are two sedimentation basins (50000 m3/day each) and two filtration buildings out of service for rehabilitation due to lack of funds.
Raw Water Supply System (RWSS)
The existing raw water supply system of Sharki WTP consists of two water way conduits and three low lift pumping stations. Anciently Sharki WTP was supplied with raw water from Mahmoudia canal through surface open channel called Elfarkha channel (Swiss Canal Street now) and low lift pumping station PS1 at Sharki WTP. In 1955 Elfarkha channel was converted to be an underground tunnel extended under Swiss Canal Street and Mahmoudia LLPS was constructed.
By the early 80’s of the last century, there were a lot of surface water pollution sources along Mahmoudia canal from Elsouf WTP to the end of the canal. These pollution loads led to deterioration the quality of the raw water flows in Mahmoudia canal and consequently affect the quality of drinking water produced by Sharki WTP. It also results in several operation problems and increase the cost of drinking water production due to the excess use of chemicals (alum and chlorine) added and increase the frequent of sand filters backwash.
Due to population increase, the urban area extension and consequently increase of drinking water demand in addition to increase surface water pollution of Mahmoudia canal, AWCO in Collaboration with the Ministry of Irrigation and Ministry of housing decided to construct Manshia 1 WTP, to divert some of Mahmoudia water to new Canal called Drinking Water Canal (DWC) to supply Sharki WTP and Manshia 1 WTP with raw water and to develop the raw water supply system for Sharki WTP. This system started to be operated in 1988. Currently, DWC supply Sharki WTP, Manshia 1 WTP, Manshia 2 WTP and El nozha WTP.
Development of RWSS of Sharki WTP required the following; construction an underground tunnel from the end of DWC to Mahmoudia pumping station (PS2), construction a new low lift pumping station at Manshia 1 WTP to lift the raw water from the DWC to the treatment unit in Sharki WTP and construction two pipe lines 1000 mm diameter each to connect PS3 by water treatment units in Sharki WTP. The PS2 supply around 70% of Sharki WTP raw water demand and PS3 supply the remaining proportion (30%).
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MATERIALS AND METHODS
The study was carried out in different departments of Alexandria Drinking Water Company and Sharki WTP.
Data collection:
A. The key persons were interviewed using a predesigned interview data collection sheets to collect data as follows:
Orascom for Engineering & Contracting staff were Interviewed using a predesigned data questionnaire to collect data such as cost of construction of tunnels, pipelines, suitable depth for digging tunnels, estimated cost of the project.
Review of the detailed Drawings for RWSS tunnel and different levels in Sharki WTP to obtain the difference in elevation between DWC and different levels in Sharki WTP to calculate the suitable head for designed system.
The following records and reports were reviewed to collect data on raw water quantities, power consumption ----etc
Review the daily operation records for raw water pumps, working hours, raw water, treated water produced and electricity consumed in Sharki WTP, Mahmoudia LLPS, Manshia WTP and other WTPs in AWCO were reviewed.
Records of Electricity Bills issued for Sharki WTP, Manshia WTP, Mahmoudia WTP.
Annual statistical analysis report issued by AWCO were reviewed.
Technical reports prepared by consulting company studies for AWCO on Alexandria WTP’s were reviewed to collect population forecast studies, specific data on AWCO WTPs’, strategic plans for AWCO.
Review of the records
Electricity consumption was calculated by using:
IV. Power consumption equations for pumps were calculated using the following formula (115)
Power consumed 𝑃=Q∗Hlosses75∗ηall
V. Electricity Bills (actual)
VI. Electricity was measured using Electric Power Quality and Energy Analyzer (Fluke 435 series п)
5 The rate of Raw water supply for Sharki WTP was calculated using
III. Reading of ultrasonic flowmeters installed on the raw water pipelines
IV. Statistical Calculation from AWCO reports.
6 The Population Forecast was carried using the following sources and methods:
I. Data from Central Agency for Public Mobilization and Statistics.
II. Study done by consulting office for AWCO.
III. Population forecast was carried out according to the standard Methods (Arthematic, and geometric methods) mentioned in the Egyptian Code of Design Principles and Conditions of Implementation for Drinking water and Drainage purification Plants.(116)
7 The RWSS alternatives were designed according to the Egyptian Code of Design Principles and Conditions of Implementation for Drinking water and Drainage purification Plants.
8 The capital costs and running cost of different alternatives was calculated for cost benefit analysis study using interview questionnaire with a Contracting company.
Performance Evaluation for RWSS
Data collected through data collection sheets and records. And to check the accuracy of the data collected from operation records, another method of power consumption measurement was used. It was carried out using “Power Quality and Energy Analyzer” (Fluke 435 series п). This instrument is accredited and certified and used for measuring the power consumed in KW.
The electric power calculated was 20622240 KW for year 2014 for RWSS of Sharki WTP as number of pumps and number of working days was calculated from operation schedule reported by operators in this year in the referred WTPs.
The average Electricity consumed by RWSS in Sharki WTP was 0.149 KW/m3
Comparing the results of power consumption from operation records with power consumption measured by Power Quality and Energy Analyzer (Fluke 435 series п), the difference is 12%. This difference may be due to the use of estimation techniques in calculation in the first method vs direct measurement in the second method.
the electrical power consumption per cubic meter of the raw water lifted in another three water purification plants run by AWCO were compared to that in Sharki WTP. They are Siouf WTP, Ma’mora WTP and Manshia1 WTP. These WTPs were selected to compare power consumed by their RWSS with the power consumed by Sharki RWSS, as two WTPs of them locates adjacent to the source of raw water (Siouf WTP and Manshia1 WTP) and the other WTPs locates far away from source of raw water (Ma’mora WTP).
The data on power consumption in the above four mentioned WTPs was obtained from AWCO 2014 operation records.
Manshia1 WTP recorded the lowest energy consumption rate due to its location (adjacent to the raw water source which is DWC) and also potential head (static head) is small. Ma’mora WTP recorded the highest power consumption as a result of the increase of the dynamic head due to long route of its intake (ductile cast iron pipeline 1500 mm diameter and 14 km length). Sharki WTP has a high power consumption rate due to the multiple LLPS’s used to lift raw water to flash mix in addition to the difference in potential head (static head) is about 19.77 meter.
Chapter 7: Summary
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Calculation of total equivalent head losses
from the calculations, 9.68 meter equivalent dynamic head losses for around 2 km RWSS length is considered very high. In such projects the slope of hydraulic gradient line is supposed to be around 2 m/km, i.e it should not exceed around 4 meters. This means that the power consumption due to dynamic head could be decreased to ½ at least of the current power consumption due to dynamic head losses. In addition there is an opportunity to reduce the static head by 2.7 meters when Sharki WTP supplied by raw water from Mahmoudia canal. The potential saving in electricity consumption due to increasing the efficiency of RWSS and the decreasing of the static head could be significant.
Preliminary data required for the new RWSS
To design a new RWSS for Sharki WTP the following studies are required; population studies, water demand studies, land use and feasibility of execution in addition to the financial analysis.
Population studies
Current population
Sharki WTP supplies the areas located in the north of Mahmoudia canal of the following districts; Sidi Gaber, Bab Sharki, Moharem Bek, El Attraeen, El Labaan, El Manshia, and El Gomrok with drinking water. In addition it shares in supply of the main lines of the North West drinking water network with drinking water. Table (5.6) represents the population served by Sharki WTP, based on CAPMAS 1996, 2006, 2016 census
Population forecast
The standard methods for population forecast stated in the Egyptian Code of Design Principles and Conditions of Implementation for Drinking water and Drainage purification Plants were used for population forecast in Alexandria Governorate. They are Arithmetic increase method, and Geometric Method.
Although the forecasted population size of Alexandria governorate in 2086 is very large if the land area of the governorate was taken into account, it will be considered as it is in this study as a worst case. The average between the two methods is 12373219 capita.
Sharki WTP production
Water production by Sharki WTP is designed to be 510000 m3/day as there are (2sedimentation basins +20 filters out of service) but the current production is approximately 380000 m3/day in winter and 430000 m3/day in summer.
AWCO Planned water production
AWCO planned to increase the production of Sharki WTP through replacement sedimentation basins {1, 2(out of service),3, 4} and 20 Degremont filter +6 sata filters by 2 Italba sedimentation basins with its filters. The total production of this set will be 180000 m3/day as utterly extension in Sharki WTP
The total production of Sharki WTP after these extensions will be 690000 m3/day as maximum increase in production for Sharki WTP.
This amount is supposed to be increased by 10 % (69000 m3/day) for backwash filters, sludge removal and losses. The total raw water discharge for RWSS of Sharki WTP is 759000 m3/day.
Design of the new RWSS
For designing a new RWSS the expected quantity of raw water inlet to Sharki WTP is as mentioned above as an utter extension for Sharki WTP.
(690000 + 69000 = 759000 m3/day).
Q= V × A
759000 m3/day = 1.24 m/sec × Area
Area= 7.06 m2
Diameter = 3 m
This area could be fulfilled through the following:
First; the use of 4 ductile cast iron pipes 1500 mm diameter.
Second; the use of one pre-stressed concrete pipe 3 m diameter.
Basis of RWSS of Sharki WTP replacement
The recommended basis on which the RWSS of Sharki WTP Replacement will be;
The flow of raw water through conduit from the end of DWC to Sharki WTP will be gravity flow in closed conduit to avoid high pressures in water conduits.
In addition the current three LLPS’s will be replaced by just one LLPS at Sharki WTP to save energy consumptions.
More ever the current 40 low voltage pumping units of will be replaced by 14 new low voltage pumping units to save energy.
Routes of raw water conduits
The available alternatives of conduit’s routes are;
The first route
The first suggested scenario is to extend the conduit from the end of DWC under the land area of Salt and Soda Company, under Mahmoudia Canal Street, under slow Swiss canal street, Swiss Canal Street, Ahmed Ismail Street and Ahmed Zewail square to Sharki WTP. The total length of this route is 2.16 Km.
The second route
The second suggested scenario is to extend the conduit from the end of DWC under the land area of Salt and Soda Company, under Mahmoudia Canal Street through El shaheeda Om saber street, El-Amir Omar Street, Tomart Street to Sharki WTP. The total length of this route is 2.05 Km.
The third route
The third suggested solution is drilling a tunnel using a tunnel boring machine (TBM) with 1.35 km length (shortest path) and with depth 16-20 meters straight-line from DWC to Sharki LLPS. The total length of this route is 1.79 Km.
Execution technology
C. Lying of pipelines through shallow excavation (3 meters depth).
This technology doesn’t need retaining of laying trenches.
The main disadvantage of this technology is the presence of many other utilities such as gas pipelines, water distribution pipelines, sanitary drainage pipelines, electricity cables communication cables,…etc.
D. Lying of pipelines in deep trenches (5-8 meters depth).
This method requires retaining the sides of the laying trenches with vertical wood or steel pile sheets and horizontal steel beams.
The presence of utilities is considered a barrier in the use of this method. Depth and width of excavation and presence of utilities will significantly increase the cost of implementation of this method.
c. Tunnel boring method
Tunnel boring method occurred using TBM which is a huge machine with different diameters in this case the diameter will be 3 meters. This machine is used for digging tunnels in different ways and conditions.
Replacement of LLPS
After the execution the conduit of RWSS of Sharki WTP as mentioned, the raw water will be collected in Sharki WTP. Design of a new pump house with new sump suitable for the level of raw water is essential to lift raw water from the sump to the flash mix inside Sharki WTP directly. The exciting three LLPSs (PS1, PS2 and PS3) which have 40 pumping units will be replaced by only one LLPS at Sharki WTP.
Q = 759000 m3/day = 31625 m3/hr
The design discharge is 759000 m3/day (31625 m3/hr) and head is 21 m. Therefore, twenty pumping units (thirteen pumping units for continuous operation and seven pumping units stand by) 2500 m3/hr discharge, 21 m head are required to fulfill the required discharge and head.
Mahmoudia canal rehabilitation
It is suggested to convert the raw water supply from DWC to be through Mahmoudia canal. This will shorten the length of conduits by around 400 m and will change the value of static head as the raw water level in Mahmoudia canal will be 0.8 m
The design discharge is 759000 m3/day (31625 m3/hr) and head is 18.25 m. Therefore, twenty pumping units (thirteen pumping units for continuous operation and seven pumping units stand by) 2500 m3/hr discharge, 18.25 m head are required to fulfill the required discharge and head.
Saving in electricity costs
The electrical energy consumed by RWSS of Sharki WTP was analyzed as follow:
Power consumed in the current situation
The average electricity consumption by RWSS in Sharki WTP is 0.149 KW/m3
Power consumed by the RWSS in 2086
If the power consumption by the RWSS of Sharki WTP continue at the exciting rate
Q= 759000 m3/day
Power consumed = 41278215 KW.year
Power consumed by the proposed system in 2086
Power of each pump = 272.5 KW (number of working pumps is 13)
Q= 759000 m3/day = 277035000 m3/ year
Anticipated total power consumed in 2086 = 31032300 KW.year
The average power consumption per cubic meter = 0.112
The power percentage saving = 24.8 %
Power consumed by the proposed system in 2086 after rehabilitating Mahmoudia canal
Power of each pump = 236.8 KW (number of working pumps is 13)
Q= 759000 m3/day = 277035000 m3/ year
Anticipated total power consumed in 2086= 26966784 KW.year
The average power consumption per cubic meter = 0.097 KW/m3
The power percentage saving = 34.9 %
Environmental impacts
Electricity production is one of the main sources of air pollution, table (16) shows the amount of air emissions resulting from the production of one thousand kilowatt electricity using oil and natural gas which is commonly used in electricity production in Egypt.
The study recommends that:
- Raise efficiency of the existed RWSS by using low electricity consuming pumps or lowering number of pumps used to minimum.
- Raise efficiency of the existed RWSS by using new pumps with high efficiency.
- Starting of construction of new extension to Sharki WTP sedimentation basins and filters to reach the planed water production which is 690000 m3/day.
- More Studies on the different alternatives to construct a new system with low energy consumption and high efficiency is required.
- Studying the constructions using TBM technology as a new technology in tunnel.
- Discussion for the recommended scenarios and selection of the suitable design for AWCO.
- Seeking for funds for this project considering it as one of the most important projects for Alexandria governorate.
- Studying the rehabilitation of Mahmoudia canal as sustainable source of raw water for a number of WTP’s
- Planning for new residential areas in Alexandria to absorb the increase in population and decrease the densely populated areas in Alexandria Governorate like Sharki WTP service area.
Planning the Moharem Bek industrial land area to guarantee a safe way for the tunnels under it.