wasit_detailed design report_updated.pdf

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NNEX 5

etailed Design Report

anuary 2008

SECOND EMERGENCY WATER SUPPLY AND

SANITATION PROJECTDETAILED DESIGN FOR WATERWORKS AND

TREATMENT PLANT AT WASIT

REPUBLIC OF IRAQ

MINISTRY OF MUNICIPALITIES AND PUBLIC WORKS

C LOTTI & ASSOCIATI


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SEWSSP

WASIT WATER TREATMENT PLANT

1,000 m3/h CAPACITY

DETAILED DESIGN REPORT

November, 2007


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C. LOTTI & ASSOCIATI S.p.A. in collaboration wi th CEB Baghdad Universi ty and Engicon

CONTENTS

Page

1. INTRODUCTION1.1 Background 7

1.2 Summary and Scope of Work 7

2. Design of Process Units

2.1 Scope of Work 8

2.2 Approach and Methodology 8

2.2.1 WTP Capacity 9

2.2.2 Raw Water Quality 92.2.3 Design Criteria 9

2.2.4 Process Unit Sizing 10

2.2.5 Process Flow / Mass Balance Diagrams 10

2.2.6 Process and Instrumentation Diagrams 10

2.3 Basis of Design 10

2.3.1 Process Design Overview 10

2.3.2 Process Functions 11

2.3.3 Process Flow 112.3.4 Water Quality 12

2.3.4.1 Raw Water Quality 12

2.3.4.2 Treated Water Quality 12

2.3.4.3 Determination of the Chemical Dose with Jar Tests 12

2.3.4.4 In-Line Chemical Dispenser 12

2.3.5 Design Parameters 13

2.3.5.1 Sludge Mass Balance 13

2.3.5.2 Filters 13

2.3.5.2.1 Filter backwash 13

2.3.5.2.2 Filter dump volume 14

2.3.5.3 Clean wash water tank 14

2.3.5.4 Wastewater holding tank 14

2.3.5.5 Elevated Storage Tank 14

2.3.5.6 Chlorination System 14

2.3.5.6 Chemical dose rates and storage 142.3.5.6.1 Alum 15

2.3.5.6.2 Chlorine 15

2.3.5.7 Service water 15

2.4 Process Calculations 15

2.4.1 Basis of Design for all Plant Flows 16


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2.4.13 Service Water Requirment 32

2.4.14 Mass Balance 33

3. Hydraulics and Hydrology3.1 Hydraulics Study 34

3.2 Hydrological Study in Al-Dujaila- River 34

4. Mechanical Design

4.1 Mechanical Equipment- General 35

4.1.1 Introduction 35

4.1.2 Scope of the Work 35

4.1.3 Design Criteria 36

4.1.4 Calculations 36

4.1.5 References 37

4.1.6 Sample of Calculations 37

4.1.6.1 Head losses calculation for raw water pumps 38

4.1.6.2 Head losses calculation for treated water pumps 39

4.1.6.3 Head losses calculation for waste water pumps 40

4.1.6.4 Head losses calculation for over flow pumps 41

4.1.6.5 Head losses calculation for backwash water pumps 424.1.6.6 Head losses calculation for service water pumps 43

4.2 Pump Station and Pipeline Hydraulic Transient Analysis 45

4.2.1 Purpose 45

4.2.2 Transient Mathematical Model 45

4.2.3 Criteria and Analysis 46

4.2.3.1 Raw Water Pump Station 46

4.2.3.2 Treated Water Pump Station 47

4.2.4 Analysis Summary and Recommendation 48

4.2.5 References 48

4.3 Mechanical Equipment-HVAC 53


4.3.2 Design Criteria 53

4.3.2.1 Cooling 53

4.3.2.2 Heating 53

4.3.2.3 Ventilation 534.3.3 Systems 54

4.3.3.1 Cooling system 54

4.3.3.2 Heating system 54

4.3.3.3 Ventilation systems 54

4.3.4 Sample of calculations 55


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4.4.4 Emergency Showers 68

5. Electrical Equipment

5.1 Introduction 695.2 Scope of Work 69

5.3 Design Criteria and Parameters 69

5.3.1 Compliance with Regulations and Standards 69

5.3.2 The Incoming Supply 69

5.3.3 Transformers 69

5.4 Methodology 69

5.5 Sample of Calculations 70

5.5.1 Load Estimation 70

5.5.2 Voltage Drop Calculations 71

5.5.3 Indoor Lighting Calculations 73

5.6 Drawings 74

5.7 Bills of Quantity 74

5.8 Specifications 74

6. Instrumentation Control and Automation

6.1 Instrumentation and Controls System 756.1.1 Introduction 756.1.2 Main Process Control Center 756.1.3 Control Network 756.1.4 Local Control Panels 766.1.5 Distributed PLCs 76

6.2 Local/Remote control 77

6.3 General Guidelines for Control Logic 776.3.1 General Control Loop Functions 786.4 SCADA Failure Modes 816.4.1 Workstations 816.4.2 PLC 816.4.3 Process I/O Modules 816.4.4 SCADA System Monitoring 816.4.5 Equipment Re-start 81

6.5 Control Descriptions 826.5.1 Raw Water Pump Station 826.5.1.1 RWPS Operation 846.5.1.2 Station Power Loss 856.5.2 Screen Air Scour 856.5.3 Sampler Control 86


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6.5.13.2 Local Mode of Operation: 1016.5.13.3 Remote Manual Mode of Operation: 102

6.5.13.4 Monitoring Requirements: 1036.5.13.5 Chlorine Motive Water Pumps 1046.5.13.6 Chlorine Scrubber System 1066.5.14 Alum System 1086.5.14.1 Alum Mixing System 1096.5.15 Treated Water Pump Station 1106.5.16 Service Water System 1126.5.17 Overflow Holding Tank/Pump Station 114

7. Architecural and General Layout7.1 Introduction 1167.2 Scope of Work 1167.3 Methodology 1167.3.1 General criteria 1167.3.2 Support Buildings 1167.3.3 Process Buildings 117

7.4 Basis of Design 1177.4.1 Codes And Standards 117

7.4.2 Primary Elements 117

7.4.2.1 External walls 117

7.4.2.2 Internal walls 117

7.4.2.3 In-situ R.C. floor and roof slabs 117

7.4.3 Finishing 118

7.4.3.1 Wall finishing 118

7.4.3.2 Floor Finishings 1187.4.3.3 Base 118

7.4.3.4 Ceilings 118

7.4.3.5 Metal works 118

7.4.3.6 Carpentry 118

7.4.3.7 Roofing system 118

7.4.3.8 Flashing 118

7.4.3.9 Water proofing 1187.4.3.10 Sealants 119

7.4.3.11 Doors and Hardware 119

7.4.3.12 Windows 119

7.4.3.13 Glass and glazing 119

7.4.3.14 Fencing 119


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8.2.1 Design Codes 122

8.2.2 Design Software 124

8.2.3 Structural Materials 1248.2.4 Foundations 124

8.2.5 Reinforced Concrete Structures : Design Basis General 125

8.2.5.1 General 125

8.2.5.2 Design Loads 125

8.2.5.3 Material Requirements 126

8.2.6 Structural Steel: Design Basis 126

8.2.6.1 General 126

8.2.6.2 Design loads 126

8.2.7 Concrete Block Work 127

8.2.8 Site Investigation 127

8.3 Sample of Calculations 127

8.4 Structural and Civil Drawings 143

8.5 General description of civil works 144

8.5.1 Non-Process Buildings 144

8.5.2 Process Buildings 1449. Ancillary Works9.1 Geotechnical Report 1489.1.1 Introduction 1489.1.2 Laboratory Works 1489.1.3 Stratigraphy 1509.1.4 Groundwater 1519.1.5 Soil Classification and Identification 152

9.1.6 Shear Strength Parameters 1559.1.7 Soil Compressibility 156

9.1.8 Chemical Tests for Soil and Groundwater 157

9.1.9 Geotechnical Design 158

9.1.9.1 Allowable bearing pressure 158

9.1.9.2 Shallow Foundations 159

9.1.9.3 Pile Foundations 159

9.1.9.4 De-watering 1609.1.10 Suitability of Materials for Re-use 160

9.1.11 Smmary of Design Parameters 160

9.1.12 Conclusions 161

9.2 Road Report 163



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1. INTRODUCTION

1.1 Background

Wasit subdistrict center is located in the south eastern part of the Wasit Governorate. It is

about 28 km to the south east of Al Kut city. The topography of Wasit subdistrict is flat. The

total population of Wasit subdistrict is about 38,293 inhabitants, about 10,500 of them are

urban and the rest are rural.

The climate in Wasit is dry and cold in the winter season and very hot in the summer. The

average annual precipitation ranges from 120 to 130mm, most of this occurs in the winter

months. The average daily temperatures range between 9-13 C in winter and 40-50 C in

summer. The main occupation in the subdistrict is agriculture and animal husbandry. Ingeneral, Wasit is considered a poor subdistrict. The rural areas in Wasit subdistrict appear to

be very populated; more than 72 percent of the population is living in the rural areas.

The main source of water in Wasit city is the Al-Dujaila irrigation canal which is a branch of

the Tigris River. Al-Dujaila canal passes through the urban area of Wasit city with continuous

water flow throughout the year. The canal is under the jurisdiction of the Ministry of Water

Resources.

Only about 40% of the total population of Wasit city is served by a piped system, the

remaining population is served by tankers or take water directly from the canal. Wasitsubdistrict center is served through an old water distribution network.

The distribution system in the city is very old and is mostly of asbestos, cast iron, plastic and

cement pipes. It has been reported that about 10% the maximum water head in the network is

about 3.0 m and may go down to 0.5 m. Only 25% of the total area is covered by existing

water facilities. The main transmission pipe is 250 mm in diameter, while the distribution

pipes diameters range from 110 mm to 200 mm.

The present project includes construction of a new 1,000 m3per hour WTP, river intake withraw water pumping station and transmission line, treated water ground storage tank, and

elevated water storage tank. The site of the new water treatment plant is on the main street but

drainage of the site might make access difficult during the rainy seasons.

It is anticipated that no negative impacts on the environments will take place due to the

sewage produced since most of water produced by the plant is utilized to improve the quality

of water consumed by the inhabitants which are presently using poor quality water.

1. 2 Summary and Scope of Work

This report has been prepared to show the detailed design of Water Treatment Plant utilizing

standard process units, structures and buildings developed by MWH for MMPW. The designs

are based on plant capacity (works throughput) of 1000 m3

/h. It is intended that standard

designs are incorporated into the site specific design with the necessary alterations. Several


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The report consists of ten chapters. The chapters describe the procedure for the design of Wasit

Water Treatment Plant utilizing both Standard Designs and design specific to a particular

capacity of works and location.

2. DESIGN OF PROCESS UNITS

A water treatment process is an assemblage of unit processes that effectively produces a

supply of safe drinking water. The treatment system generally consists of four or more

interrelated components. These components include coagulation, flocculation, clarification,

filtration and disinfection with the necessary process control and instrumentation. Since the

unit processes must be interrelated, the operation of each component affects the performanceof others, and then the entire system.

2.1 Scope of Work

The design of Wasit water treatment plant is based on the standard design of WTP for a

capacity of 1000 m3/h of treated water. The standard design was incorporated into the specific

site and conditions of Wasit City with necessary alterations. Several alterations will be

explained in this chapter. The chapter also highlights the procedures which were undertaken

for raw water quality testing, followed by descriptions for developing the process design

utilizing calculation spreadsheets, Process Flow Diagram with Mass Balance, Hydraulic

Profile Diagrams, and Process and Instrumentation Diagrams, The process design will

determine the amendments which are required to the standard process units.

2.2 Approach and Methodology

The basic approach is that the water treatment plant should be designed to produce a

continuous supply of safe drinking water according to raw water characteristics and theenvironmental conditions. The specific approaches of the design process are:

1. Evaluation of local conditions carefully.

2. Creation of a reasonably conservative design and cost-effective to construct.

3. Creation of a simple, reliable, effective, and proven system by applying the bestknowledge and skill to the design.

4. Designing a plant that is easy and safe to construct as well as simple and safe tooperate.

5. Allowing for maximam and minimum operational flexibility.

The Standard Designs are based on river sources. However, the raw water quality varies

depending on location. The following parameters are those for which treatment is provided.


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The stated capacity of Wasit WTP is 1000 m3of treated water output. In order to achieve the

necessary treated water output, the quantity of raw water will have to account for the amount

of water lost through the process.

The main factor that affects the water losses and hence the raw water flow is the raw water

quality. Raw water with high suspended solids content will produce a large amount of sludge

and hence the amount of water lost throughout the treatment will increase.

Allowance has also be required for filter backwash water and filter rinse to waste during start

up following a backwash. These quantities was calculated and shown in the material balance

sheet. The Process Flow Diagram (PFD) and Mass Balance Diagram (MBD) were developed

to assist in the design of hydraulics, process pipe work and wastewater disposal.

2.2.2 Raw Water Quality

The turbidity of the raw water influences the amount of sludge produced and the coagulant

dose. The amount of coagulant required will also influence the amount of wastewater. Typical

analysis of raw water quality includes

Total dissolved solids (TDS) Total suspended solids (TSS) pH Turbidity (Tur) Electrical conductivity (EC) Total hardness (TH) Alkalinity (Alk) Magnesium (Mg) Calcium (Ca)

Chloride (Cl)

Analysis of a set of raw water samples taken over a suitable period from Al-Dujaila- River

was carried out to evaluate the coagulant dose and waste streams. The full raw water quality

data is shown in Table 1. The analysis is done by the Local Municipal laboratory located at

Wasit City. The sample dates and temperatures were included.

Table 1 Wasit Raw Water Quality Data (Source : Al-Dujaila- River)Date Temp Turb. pH E.C. Chlor. Alk. T.H. Ca Mg TDS TSS

25-01-2006 17 25 7.70 1393 81.7 160.0 500.0 97.2 61.8 928 5219-02-2006 25 115 8.10 1404 163.4 160 473.5 117.5 43.1 936 125

29-01-2007 20 30 7.50 1395 85.0 165 495 100.0 65.0 930 65

22-03-2007 22 60 7.84 1211 132 114 620 144 63.7 774 52

11-05-2007 26 53 7.95 1283 90 120 480 112 49 593 55

M 22 56 6 7 818 1337 2 110 42 143 8 513 7 114 1 56 52 832 2 69 8


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2.2.4 Process Unit Sizing

The size of most of the process units is the standard unit size of 1000 m3/h plant. Standard

Designs were reviewed and modified according to the raw water quality and consequent

losses through the treatment process. The amount of raw water required depends on the water

losses through the treatment processes. The flows were checked on the mass balance to ensure

the raw water intake and pumps are sized correctly.

The wastewater holding tank size depends on the quantity of sludge produced. The size of the

tank as well as the diameters of the pipes carrying clarifier sludge were recalculated and

checked.

For the Chemical Building storage capacity and mixing tank volumes, the coagulant dosing

requirements was rechecked and determined by the jar tests carried out on the raw water.

The capacity of the treated water pumps was reviewed and checked according to the

requirement of the distribution network.

The calculation of these quantities and the unit sizing are shown in the calculation sheets

located at the end of this chapter.

2.2.5 Process Flow / Mass Balance Diagrams

The flows across the treatment processes vary according to the site. The main factors that will

influence these flows are the amount of sludge and wastewater produced and the amount of

service water required. These amounts were calculated. A Process Flow Diagram (PFD) and

Mass Balance Diagram (MBD) were prepared for Wasit Site and shown in the calculation

sheets located at the end of this chapter. The process flow diagram with the mass balance

table are also included in the set of the P&ID sheets (Drawing Sheet No. 13-202-7021).

2.2.6 Process and Instrumentation Diagrams

The Process and Instrumentation Diagrams (P&ID) are checked for standard WTP of 1000

m3/h and modified according to the changes in the particular site of Wasit. The diameters of

all interconnecting pipe work, wastewater pipe work and pipe work within process units were

checked recalculated and modified for each Process Unit accordingly.

The destination of the overflow outlets and waste water outlets were modified according to

the new site. The Tag Numbering for the equipment, valves, etc, was checked and therequired alterations were made on the streams and instrumentations in the P&IDs.

2.3 Basis of Design

The basis of design describes the technical basis of the design process. The following

references were used in order to establish the Basis of Design:


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streams generated from the treatment process will be disposed to Nagara River located near

the WTP site without any treatment. The process is designed to be operated continuously

without frequent start-up and shut down.

2.3.2 Process Functions

The main process functions include:

Extraction and transmission of raw water from the intake area to the treatment plantarea.

Makeup, storage, injection, and in-line mechanical mixing of flocculation anddisinfection chemicals and raw water.

In-line dispersion of coagulant (Alum) in the raw water main.

Rapid gravity filtration of the settled water.

Storage and injection of disinfection chemical (Chlorine Gas) into the filtered waterstream.

Prechlorination Facilities for raw water entering the plant. Collection and storage of treated water, including establishment of disinfection contact

time.

Transmission of treated water from the treatment plant site to the DistributionNetwork

Extraction and storage of dirty backwash water from the filters and sludge from theflocculator/clarifiers.

Collection and storage of miscellaneous process wastes.

Transmission of wastewater and sludge and miscellaneous process wastes from thetreatment plant site to the near river outfall.

Collection and storage of emergency overflow water.

Transmission of overflow water to the near river outfall.

Provision for future incorporation of advanced chemical treatment (polyelectrolyte)processes

2.3.3 Process Flow

Raw water is pumped from Al-Dujaila- River to the water treatment plant via the raw water

i li O i id th t t t l t th t fl i t d P hl i ti


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Filtered water is treated with chlorine and flows through the chlorine contact tank to the

treated water storage tank. The treated water pumps transfer treated water to the Distribution

Network via treated water pipeline.From the splitter box onwards, the flow gravitates through the treatment works, ending up in

the treated water storage tank. A portion of the treated water flow is extracted for use as

service water and also domestic water on the treatment plant site. Emergency overflow water

is directed to a dedicated overflow tank containing a pump to transmit the water to the river.

2.3.4 Water Quality

2.3.4.1 Raw Water QualityRaw water quality is dependent upon the river source, local conditions and in some cases time

of year. Samples taken over a one year period were analyzed to understand the variability of

the water quality, particularly with regard to pH and turbidity.

The basic parameters analyzed are: pH, temperature, turbidity, conductivity, alkalinity, total

hardness, calcium, magnesium, chloride, TDS, TSS, TOC, and aluminum. Table 1 shows a

typical water quality data for Al-Dujaila- River.

2.3.4.2 Treated Water Quality

The plant was designed to treat the above raw water, and to produce the following quality of

water, to the following standards:

Target Turbidity 0.5 NTU average, 1 NTU maximum E coli or thermo tolerant coliform bacteria 0 in 100 ml sampleIt is anticipated that the target residual metals will be as follows, subject to confirmation

of concentrations in the inlet raw water,

Aluminium Less than 0.2 mg/l Iron Less than 0.2 mg/l

2.3.4.3 Determination of the Chemical Dose with Jar Tests

Jar Tests was carried out to establish the average alum dose rate for the WTP. The dose rate

was used in the calculations for dosing pumps and chemical storage.

In Jar Tests, a range of alum doses (0 to 60 mg/l) should be applied to the raw water under

standard Jar Test conditions of rapid mixing, slow stirring and settlement. The settled watershould be analyzed for pH, turbidity and total and dissolved aluminum. The optimum alum

dose is the dose after which increasing the alum dose does not significantly reduce the

turbidity of the settled water (see figure). The dissolved aluminum should be less than 0.2

mg/l. If higher or lower alum doses are required to achieve the optimum alum doses then the

Jar Test should be repeated


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Most of the design parameters are standard for the plant designs. However some factors affect

the process calculations, which are detailed in this section.

2.3.5.1 Sludge Mass Balance

To achieve the desired plant flow at the outlet, the inlet flow has to be greater to account for

the losses through the process. The losses through the processes are as follows:

Clarifiers Intermittent desludging. Wash Water Tank filling: the wash water tank is filled from the filter outlet flow. Filter dump volume: the mass balance assumes there is 2 dump volumes lost per day

from the filters, during the backwash cycle.

Treated Water Tank: the service water is taken from the treated water storage tanks

The volume of clarifier sludge depends on the raw water quality and the coagulant dose. The

instantaneous maximum flow can be calculated assuming that all the clarifiers desludge at the

same time. Using the raw water turbidity, the amount of clarifier sludge produced can be

predicted, using the following equation:

= 1

A234.0T4S1000

T2S1000CS

ic

oc

Where:

S: Sludge flow (MLD)

Sc: Sludge solids concentration - 8kg/m3 or 0.8% (used for medium values of turbidity)

To: Clarifier outlet turbidity taken as - Min 1 NTU

-Max 2 NTU

A: Alum dose (50mg/l)

Ti: Clarifier inlet turbidity (NTU)

C: Clarifier outlet flow (MLD)

2.3.5.2FiltersThe filters are designed on the following parameters:

Media type/depth: - Dual media-Anthracite No 2 750 mm depth

- Sand 0.65mm NES 500 mm depth

-Gravel 4 9 mm 50 mm depth

Clogging head: 3 m


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Filter outlet to wastewater tank pipe diameter- Assume a velocity of 1 m/s.

2.3.5.2.2 Filter dump volume

The mass balance assumes there are 2 filter dumps per day, to the wastewater holding tank.

This volume is calculated as follows:

Filter dump volume = volume above weir + volume of wash water troughs + volume below

weir to the base of the siphons.

2.3.5.3Clean wash water tank

The clean water tank is filled by part of the filtered water overflowing a weir, such that the

flow going forward to the Chlorine contact tank is not starved. This is approximately 10% of

the max plant flow. The tank is sized using the following parameters:

Sized for 2 filter backwashes Each backwash uses 4.5 Bed Volumes of wash water.The flow rate to fill the wash water tank is calculated from the mass balance assuming:

Wash rate for each filter: Min - once a dayMax - twice a day

2.3.5.4 Wastewater holding tank

The wastewater holding tank was designed as follows:

Sized to hold one filter wash, plus 1 hour of average clarifier flow and 30 minutesrinse to waste

The TWL of this tank should be below the invert level of the filter wash waterchannel.

The return pumps are sized on the following details:

To evacuate the tank in 2 hours. 2 duty pumps. A pipe velocity of 1.5 m/s suction and 2.5 m/s discharge.

2.3.5.5 Elevated Storage Tank

An elevated storage tank should be designed, constructed and installed in raw water intake area to

supply treated water to Wasit City. The EST should be made of galvanized pressed steel with total netcapacity of 1200 m

3. The height of steel structure should be 30 m. The design of EST is to be the

responsibility of the contractor who will be awarded the construction of the project. The design should

include structural design (foundations and steel design), geotechnical and topographic field survey, all

pipe connections, local control instruments, and all other necessary requirements.

2 3 5 6 Chlorination System


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2.3.5.7.1 Alum

Chemical - Aluminium sulphate Al2(SO4)3.14.3H20.

Form/delivery - Granular Bulk storage - 30 days at average dose rate in 50 kg bags.Maximum dose rate - The dose can be predicted using jar tests. 50 mg/l has been used

for the designs.

Chemical makeup - 10% solution, with a S.G. of 1.06-Makeup tanks standard size - 18.9 m3

- Duty makeup tanks - 1 days dosing at max plant flow

- 1 duty makeup tanks- 1 additional tank standby

2.3.5.7.2 Chlorine

Prechlorination-Predicted dose 3mg/l

-1 duty drums

-No standby is required Disinfection-Predicted dose 2mg/l

-Number of drums - 1 duty/1 standby

-Calculated using maximum draw off rates from a chlorine drum as follows:

30 oC = 15kg/hr

20 oC = 10kg/hr

15 oC = 5kg/hr

Storage- Maximum 30 days

- A 9 (1 tonne) chlorine drum store was adopted for the Standard Designs

2.3.5.8 Service water

The service water is taken off from the treated water tank

Assumed Service water consumption 8 m3/day Assumed wash down water 23 m3/day

2.4 Process Calculations

Process design was done utilizing calculation spreadsheets, by EXEL software considering

the main factors affecting the water treatment plant of Wasit. Mass balance was done to

calculate the amount of sludge, amount of water lost throughout the treatment process, filter

backwash water and filter rinse alum and chlorine doses required Unit sizing and


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C. LOTTI & ASSOCIATI S.p.A. in collaboration wi th CEB Baghdad Universit y and Engicon

2.4.1 Basis of Design for all Plant Flows

Flash mixing

Alum addition/energy input will be by inline mechanical mixer

Clarification

The Flocculation/Clarification plant will consist of a number of streams

Each stream will comprise the following:

Flocculation stage comprising 3 No chambers to give an overall nominal residence time of 30 mins.

Nom.length 4.45 m

Nom. width 4.45 m

Nom. depth 4.45 m

500 m3/h nett Clarification stage designed on a maximum velocity of 0.65m/h on the projected plate area.

Nom.length 9 m

Nom. width 9 m

Nom. depth 4.4 m

Flowrate 1000 m3/h

No of Streams 2 500 m3/h

Filtration

The filters will be of the single cell type with width 4.75m (nominally internal wall to wall)

Flowrate 1000 m3/h

No of filters n 5

Length 5.2 m

Width 4.75 m

Area 24.7 m2

n Velocity 8.1 m/h

n-1 Velocity 10.1 m/h

Based on nominal flows

Filter media ES mm Depth m

Sand 0.65 0.5

Anthracite No 2 1 3 0 75


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Flocculation stage comprising 3 No chambers to give an overall nominal residence time of 30 mins.

Nom.length 4.45 m

Nom. width 4.45 m

Nom. depth 4.45 m

Clarification stage

Nom.length 9.0 m

Nom. width 9.0 m

Nom. depth 4.4 m

Filtration

There will be 5 no filters of the single cell type

No of filters n 5

Length 5.2 m

Width 4.75 m

Area 24.7 m2n Velocity 8.1 m/h

n-1 Velocity 10.1 m/h

Filter inlet channel size

Max inlet flow to the block of filters 1030 m3/h

Flow down channel 0.3 m/s

Area of channel 0.95 m2Width/height 2

Water depth 0.69

Channel width 1.38

Adopted width 1.00 m

Max outlet flow from block of filters 1001 m3/h

Flow down channel 0.3 m/s

Area of channel 0.93 m2Width/height 2

Water depth 0.68 m

Channel width 1.36 m

Adopted width 1.50 m


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2.4.3 Flocculation

PROJECT TITLE Wasit

PROJECT NO

PROCESS UNIT FLOCCULATION TANKS

DESCRIPTION 2 STREAM

PREPARED BY DATE 28/10/2007

CHECKED BY DATE

VERIFIED BY DATE

VERSION NO DATE

INFLUENT CONDITIONS NOTES

AVG MIN MAX

INFLUENT FLOW Ml/d 8.37 25.48

INFLUENT TEMEPRATURE C 10 5 30

DESIGN CONDITIONSRESIDENCE TIME REQUIRED s 1800 30 MINS -(IN 3 CELLS)

TOTAL VOLUME REQUIRED m3 531 PROCESS VOLUME ONLY

TOTAL VOLUME INSTALLED m3 531 FROM ABOVE OR KNOWN

NO OF STREAMS - 2 INPUT

NO OF UNITS PER STREAM - 3 SEE BASIS OF DESIGN

DYNAMIC VISCOSITY kg/m s 0.001308 0.001519 0.000801 CALCULATED

VOLUME PER STREAM m3 265.4 CALCULATED

VOLUME PER UNIT m3 88.5 CALCULATED

LENGTH PER STREAM m 13.37 4.45 INPUT

WIDTH PER STREAM m 4.46 4.45 INPUT

DEPTH PER STREAM m 4.46 4.47 CALCULATED

LENGTH PER UNIT m 4.45 CALCULATED

ASSUMED EFFICIENCY % 100% SEE GUIDELINES

OPERATING CONDIITONS AVG MIN MAX

RESIDENCE TIME s #DIV/0! 1800 5481 CALCULATED

MIXING - PER UNIT AVG MIN MAX

REQUIRED G - 70 Choose gearbox to provide 10 - 70s-1


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LENGTH m 13.35

WIDTH m 4.45

DEPTH m 4.5

OPERATING CONDIITONS

RESIDENCE TIME s #DIV/0! 1800 5481

0 s 0 0 0

MIXING

SELECTED POWER kW 1.1

ACTUAL G s-1

74

2.4.4 Clarifier Plate Pack Design

Unit size

Q = 531 m/h

Rate 0.67 m/h

Proj.Area 792.4 mAny plate 1.5 m wide Avail. F. C -6 m

Area 2.41 m Width -1.5 m

No. requd 329 Flow per trough 0.036868 m/s

Rows 4

82.2 No

Horl. 63.5 mm

5220 mm

Offset 15556775 m long

Allowing for shaft

pack m pack m pack m No.plates Area m b1 Length

22 50.61 17 38.56 18 40.97 17 38.56 1080 2635

Area requd 792.4 m 18 40.97 1144 2699

15.7 packs 20.5 packs 19.3 packs 19 43.38 1207 2762

4 Rows 4 Rows 4 Rows 20 45.79 1271 2826

3.91 packs 5.14 packs 4.84 packs 21 48.2 1334 2889

7147 mm long 8035

mm

long 8416 mm long 22 50.61 1398 2953

Width 1.5 23 53.02 1462 3017

2 6 2 6 63.5 mm horzl. distance

2 4 2 4

t k 20 k 20


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2.4.5 Clarifier Hydraulics

Comprising 2 no 541 m3/h units

TWL in Filter inlet channel 4.505

Connecting channel between clarifiers 10 m TBC

and filter block

Velocity in channel 0.3 m/sArea of channel 0.98 m2

Width 1.40 m

Adopt width 1.40 m

Water depth 0.70 m

Channel losses assumed negligible

Exit loss into filter channel K 1 0.005 m

TWL in connecting channel 4.510

Entry loss into channel K 0.5 0.002TWL in clarifier outlet channel 4.512

TWL in clarifier launders 4.512

Assumed Freefall into lamella launders 0.2 m

Depth of launders

TWL in clarifier 4.712

Outlet to RGF Channel

Stop Log Frame

4.9644.844.745.504.7124.5124.5124.510

4.8104.962

0.272

Overflow

Raw Water Inlet

Lamella Splitter Box


22/180


Losses through flocculator chambers

Loss under baffle

Length of bafffle 4.45 m

Entry slot depth 0.2 m

Velocity 0.17 m/s

Headloss under baffle 0.004 m

Headloss over submerged baffle assumed 0.000 m

Perforated baffle

No of holes 20

Dia of holes 0.120 m

Area of holes 0.226 m2

Headloss 0.022 m

TWL upstream of perf. Baffle 4.741

Splitter box

Free drop 0.100 m

Soffit of weir 4.841Head over weir (assume not submerged)

Weir length 2.000 m

Head over weir 0.120 m

TWL inlet compartment 4.961

Clarified water overflow weir

Rise in level to overflow weir 0.3 mSoffit of weir 4.810

Length of weir 2.8 m

Flow rate 1061.8 m3/h


TWL over weir 4.962

Freeboard to top of Walls 0.539

Top of Wall 5.501


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2.4.6 RGF Trough Location

Filter inflow 24972 m3/d from mass balance Levels Refer to True Datum

1041 m3/h

Comprising 5 No Filters 24.7 m2 area

TWL 20.013

16.420 Syphon level

16.655 Expanded media level

16.120 Normal media level

16.00 Natural ground level

14.870 Bottom of the media level

13.720

Head losses through filter Datum TWL Filter outlet channel

No of filters 5

Actual Level m

TWL in FW channel 16.000

Rise to inlet weir 0.2 m 16.200Soffit of weir 16.200

Weir length 1.2 m

Water depth 0.68

Invert of channel 15.319

Max flow per filter 260 m3/h with one filter out for washing

Head over weir 0.105 mTWL over weir 16.305

Weir height above media 0.08 m

Top of media 16.120

Pipe velocity 0.8 m/s

Pipe dia 0.34 m


24/180


Exit loss 1 1 0.07 0.75 0.029 0.029

Butterfly valve 1 1.54 0.07 0.75 0.029 0.044

Tee (with rinse pipe) 1 0 0.07 0.75 0.029 0.000

Entry loss into pipe 1 0.5 0.07 0.75 0.029 0.014

Pipe length Length m Re

TBC but to allow for future 0.4 6 0.00015 0.072 0.751 197768 0.008

installation of flow meter Total 0.008

Apparent level in filter outlet 16.313

Filter max velocity 10.53 m/h (Turbidity target 0.5 NTU, 1 NTU max)

Head loss (1/ES)^1.85 x FR^1.21 x 10^(0.23429-0.0111T)x14.45415

Loss through 0.65mm media 0.84 m/m 0.42 m

Loss through No 2 anthracite 0.22 m/m 0.16 m

Clogging head adopted 3.00 m

Total media loss 3.58 m Loss inc nozzles say 3.700

TWL of filters 20.013

Top of media 16.120

Anthracite depth 0.750 m

Sand depth 0.500 m

Gravel depth 0.05 m

Slab thickness 0.200 m Underside of slab 14.620 m

Depth floor/ underside of slab 0.900 mFilter floor level 13.720

Anthracite expansion 48%

Sand expansion 35% assumed

Expanded media depth 0.535 m

Margin to underside of trough 0.178 m

Depth of trough 0.56 m

Top of washweir 17.393

Head of water above media 3.893 mHead over trough 0.047 m

Head loss through opening in wall 0.05 m sized to suit

TWL over trough 17.440 m

Expansion media level 16.655 m

Underside of trough level 16.833 m


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2.4.7 Filter

Filter inflow 24972 m3/d from mass balance

1041 m3/h

Comprising 5 No Filters 24.7 m2 area

4.505 4.455 4.350

4.197

TWL 4.100

Wash trough ( 2 No)

1.393

0.120

-2.280

Head losses through filter Datum TWL Filter outlet channel

No of filters 5

Actual Level m -1.13

TWL in FW channel 0.000

Rise to inlet weir 0.2 m 0.200

Soffit of weir 0.200 16.12

Weir length 1.2 m

Water depth 0.68

Invert of channel -0.681

Max flow per filter 260 m3/h with one filter out for washing


TWL over weir 0.305

Weir height above media 0.08 m

Top of media 0 120

Channel roof level

1.093

Filtered Water Channel

-0.681

FW Overflow

0.4940.200

0.350

0.305

0.000


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Fittings Size No K Flow VelocityVel.Head Headloss

mm m3/s m/s m m

Exit loss 1 1 0.07 0.75 0.029 0.029

Butterfly valve 1 1.54 0.07 0.75 0.029 0.044

Tee (with rinse pipe) 1 0 0.07 0.75 0.029 0.000

Entry loss into pipe 1 0.5 0.07 0.75 0.029 0.014

Pipe length

Length

m Re

TBC but to allow for future 0.4 6 0.00015 0.072 0.751 197768 0.008

installation of flow meter Total 0.095

Apparent level in filter outlet 0.400

Filter max velocity 10.53 m/h (Turbidity target 0.5 NTU, 1 NTU max)

Head loss (1/ES)^1.85 x FR^1.21 x 10^(0.23429-0.0111T)x14.45415Loss through 0.65mm media 0.84 m/m 0.42 m

Loss through No 2 anthracite 0.22 m/m 0.16 m

Clogging head adopted 3.00 m

Total media loss 3.58 m Loss inc nozzles say 3.700

TWL of fil ters 4.100

Top of media 0.120Anthracite depth 0.750 m

Sand depth 0.500 m

Gravel depth 0.05 m

Slab thickness 0.200 m Underside of slab -1.380 m

Depth floor/ underside of slab 0.900 m

Filter floor level -2.280

Anthracite expansion 48%

Sand expansion 35% assumed

Expanded media depth 0.535 m Expansion media level 0.655 m

Margin to underside of trough 0.178 m Underside of trough level 0.833 m

Depth of trough 0.56 m

Top of washweir 1.393

Head of water above media 3.980 m

H d t h 0 047 TWL t h 1 440


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TWL inlet channel 4.505

Filtered water Overflow weir

Length of weir 3.000 m into washwater tank (overflow from wash water tank)


Rise to overflow weir 0.350

Soffit of weir 0.350

TWL over weir 0.494

Soffit of channel roof 1.093

Overflow pipework

Flowrate 24726 m3/d

Dia 0.6 m

Velocity 1.01 m/s

Siphon

Adopt no of siphons per filter 3 1.393 Weir level

Dia of siphon 0.15 m

Height of siphon 0.3 m

0.420 Drain down point

2.4.8 Clean Wash Water Tank

Concept is that part of the filtered water overflows a weir into the tank, such that the flow going forward to the

Chlorine contact tank is not starved.Inlet flow to washwater tank about 10% of max plant flow.

Flow into tank 104.05 m3/h at max flow

69.4 m3/h at min flow

Volume of tank 278 m3 nett

Assume weir length 1 m

Max head over weir 0.064 m


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Adopted dia 0.45 m

Outlet penstock area 0.36 m2

Washwater velocity 1.05 m/s

Head loss 0.15 m

Ai r scour blowers (2 no)

Air scour velocity 45 Nm3/2.h

Flow 1111.5 Nm3/h

Velocity in pipe 20 m/s

Pipe dia 0.140 m/sAdopted dia 0.15 m

2.4.9 Chlorine Contact Tank

Twin compartment (to allow cleaning)

Inlet flow 24031 m3/d

Contact time 30 mins

Volume 500.6 m3

Assumed eff 100%

as this is taken into accountin the 30 mins

Temp C 5

Kinematic visc 1.52E-06

g 9.81DH DH = (0.25LV^2)/((2Dg((log((k/3.7D)) + 5.74 /(Re^0.9)))^2))


mm m3/s m/s m mExit loss intoCCT 0.7 1 1 0.28 0.72 0.027 0.027Butterfly

valve 0.7 1 1.54 0.28 0.72 0.027 0.041

Tee 0.7 1 1.2 0.28 0.72 0.027 0.032Entry loss into

pipe 0.7 1 0.5 0.28 0.72 0.027 0.013

0.7 Length m RePipe lengthA d


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2.4.10 Sludge System

Based on Al-Dujaila raw water characteristics

CLARIFIER

Turbidity

F

Cf

C

Raw water 57 NTU mean Cw

25 NTU min F

115 NTU max

Clarified water 2 NTU maxClarified water 1 NTU min W

Cw

Chemical addition

Alum dose 50 mg/l as .14.3 H2O- to be confirmed

Assumed ratio SS/NTU 4 from rw quality data

Solids concentration 8.00 kg/m3 (0.8%)assumed for low and medium turbidities10.00 kg/m3 (1%)assumed for high turbidities

Solids production 236 mg/l mean

104 mg/l min

468 mg/l max

Max flow average turbidity

Clarified water flow C 24.73 MldFeed concentration Cf 240 mg/l

Clarified water conc. Cc 2 mg/l

Sludge blowdown conc Cw 8000 mg/l

Feed flowF 25.48 Mld

Sludge blowdown W 0.76 Mld

Max flow max turbidity

Clarified water flow C 24.73 Mld

Feed concentration Cf 472 mg/l

Clarified water conc. Cc 2 mg/l

Sludge blowdown conc Cw 10000 mg/l

Feed flowF 25.94 Mld

Sludge blowdown W 1.22 Mld


30/180


Max flow max turbidity 12189 kg/day 11514.75

FILTERS

Inlet turbidity 2 NTU max

Outlet turbidity 0.1 NTU for design basis

Flowrate max 24726 m3/d

Flowrate ave 24726 m3/d (for solids calc basis)

Flowrate min 8369 m3/d 44.506238

Filter bed volume 30.875 m3

Washwater BV 4.5Wash water volume 139 m3

No of backwashes 5 per day

Dump area 30.6 m2 approx. assumes weir wall thickness 0.25m

Depth from TWL to weir 2.71 m

Depth from weir to siphon 0.97 0.3 above media for siphon

Dump volume 110m3 per filter comprising vol above weir + vol of 2 no washwater troughs+ volbelow troughs

Max wash volume per day 695 m3 excluding dumpMin wash volume per day 347 m3

Max wash volume per day 914 m3 assuming two dumps per day

Solids load 94 kg/d assumes SS/NTU ratio = 2

Solids concentration 0.1 kg/m3 max excluding dump

Min wash volume per day 347 m3

Solids load 32 kg/d assumes SS/NTU ratio = 2

Solids concentration 0.1 kg/m3

Outlet pipe to wastewater tank

Max flow 1360.5 m3/h

Velocity 1.0 m/s

Dia 0.7 m

2.4.11Wastewater Holding Tank

Sized to hold one filter wash plus 1 hour of average clarifier flow + 30 mins rinse to waste

The TWL of this tankshould be below the invert level of the filter

h t h l


31/180


Absorbed power 4.29 kW

Return pumps ( 2 duty)

Evacuate tank in 2 hours

Flow rate required 215 m3/h

Flow per pump 107 m3/h per pump

Pipe length

Pipe velocity 1.5 m/s

Pipe dia 0.22 m

Adopted dia 0.25 m

discharge head mPump heat to be confirmed when pipe route finalised

Individual Pump

Flow 107 m3/h

Pipe dia 0.15 m

Velocity 1.69 m/s

Temp C 5

Kinematic visc

1.52E-06

g 9.81

DH DH = (0.25LV^2)/((2Dg((log((k/3.7D)) + 5.74 /(Re^0.9))) 2))


m m3/s m/s m m

Exit loss 0.25 1 1 0.06 1.21 0.075 0.075

Butterfly valve 1 1.54 0.06 1.21 0.075 0.116

NRV 1 1.7 0.06 1.21 0.075 0.128

Tee 1 0 0.06 1.21 0.075 0.000

Bends 12 0.75 0.06 1.21 0.075 0.677

Pipe length Length m Re

0.25 3500 0.00015 0.060 1.21 199942 20.474


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2.4.12 Chemical Storage and DosingAlum

Max flow 25.48 Mld

Dose rate adopted 50 mg/l Al2(SO4)3.14 H2O

Solution strength 10%

Alum consumption 1258.00 kg/d

Solution flow 12580 kg/d

SG of 10% solution 1.06 approx.

Flowrate 0.49 m3/h

Water addition 11.3 m3/d

Pump flow 0.50 m3/h

Alum granules delivered in 50 kg bags on a 1 tonne pallet.

Dimensions of pallet

Nett storage capacity 19.0 m3 Weight of Alum solution 20128 kg

Water depth 2.5 m Quantity of Alum 2012.8 kg

Area 7.60 Amount of water 18115.2 kgL = W 2.76 Volume of make up water 18.079042 m3

adopt L = W 2.5 m Capacity of tank 1.6

Liquid depth 3.04 m

Freeboard 0.5 m

Overall heightadopted 2.50 m

Adopt Duty and standby tanks

Chlorine Dosing

MaxFlow 25.48 Mld

Max dose 5 mg/l

Chlorine consumption 127.4 Kg/d

30 days storage 3.8 Tonne

Adopt 9 1 Tonne drum store for commonality

Future Polyelectrolte dosing

Raw Water

A d d 0 2 /l

C LOTTI & ASSOCIATI S A i ll b ti i th CEB B hd d U i it d E i


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Consumption max 79.5 Kg/d

Concentration 0.20%

Volume 39.73 m3/d

Tank dia 2.5 m NB Preferable to install an auto polyprep unit

depth 8.09

Adopt 3.0 m

Weight required

in 30 days 2384.1 say 32 No 25 kg bags

2.4.13 Service Water Requirements

Alum make up 18.1 m3/d

Polyelectrolyte 0 m3/d ( Future requirement and not taken into consideration)

Chlorine 22.8 m3/d assuming no prechlorination ( intermittent)

Potable to houses

Population equiv 20 assumed

Consumption p.e 400 l/p.e

Consumption per day 8 m3/d

Washdown 23 m3/d assumed

Treated water losses max. 31 m3 max /day

Treated water losses min. 22 m3 min /day assuming min flow

Service water tank

Sized for a nominal 6 hours

Volume 2.05 m3

Dia 2 m

Straight side 0.653 m

Adopt 2 m dia

C LOTTI & ASSOCIATI S p A in collaboration wi th CEB Baghdad Universit y and Engicon


34/180


Ministry of Municipalities and Public Works Republic of Iraq 4/11/07

Second Emergency Water Supply and Sanitation Project Wasit Detailed Design Report/fdDetailed Design Report c.a.: F249A

33

2.4.14 Mass Balance

To River

Stream Description F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11

Fluid Raw Water Conditioned RW Clarified Filtered Treated Sludge Sludge Sludge Filtered Filtered Treated

Flow Regime Continuous Continuous Continuous Continuous Continuous Intermittent Intermittent Continuous Intermittent Intermittent

Flow

Instantaneous max m3/h 371 1360 104 1360

Maximum/max solids m3/d 25945 25945 24726 24031 24000 1219 914 1914 695 695 31

Maximum /av solids 25483 25483 24726 757 695

Minimum m3/d 8369 8369 8369 8022 8000 0 347 347 347 347 22

Mass flowInstantaneous kg/h 3706

Maximum kg/d 12189 94

Average kg/d 6059

Minimum kg/d 0 32

Service water Tank

F11

Inlet PumpingStation

LamellaClarifiers

Rapid GravityFilters

Treated waterStorage Tank

Alum

F1 F2

Clean Wash watertank

F3 F4

F7

F6

ChlorineContact Tank

Waste WaterHolding Tank

F9

F10

F5

F8

ESTDistribution


35/180


36/180

C. LOTTI & ASSOCIATI S.p.A. in co llaboration with CEB Baghdad University and Engicon

4. MECHANICAL DESIGN

4.1 Mechanical Equipment General

4.1.1 Introduction

The raw water system transfers water from the Al-Dujaila- River to the flocculators/clarifier via the raw

water pipeline of 500 mm in diameter. The raw water pumping station is located on the Al-Dujaila-River bank and consists of an above-ground pump room and a below-ground wet well. The pump room

is located above wet well and consists of four vertical turbine pump (one standby) each with flow rate

of 350 m3/hr and 11.8 m head.

The treated water pumping station consists of a pump room and electrical room located above the

pumping station. The treated water storage tank chambers act as wet wells for the treated water pumps

and service water pumps. The treated water pumping station consists of four electric driven, two speed

vertical turbine pumps (one standby) each with capacity of 333.3 m3/hr and with head of 40.8 m. The

treated water is pumped from treated water storage tank to the elevated storage tank with 30 m head via

the treated water pipeline of 500 mm in diameter. The treated water pipeline also supplies the site

potable water system.

In backwash system, the two 100% capacity backwash pumps are provided. They are designed for 1350

m3/hr which is equivalent to a wash rate of 55 m

3/hr.This is sufficient to provide the necessary bed

expansion at a water temperature of 30oC. The backwash pumps will operate in alternating duty with

one serving as a standby.

Filter backwash water, clarifier sludge, and miscellaneous process wastes are routed from structures

and process units to the wastewater holding tank. All flow is by gravity with process unit sources

operating under the static heads in each chamber. Wastewater will be discharged by three pumps (one

standby) each with capacity of 410 m3/hr and a head of 12.2 m back to the Dujaila River downstreamof the plant intake via the wastewater pipeline of 250 mm diameter (see drawing no. 13-231-2212).

An emergency overflows from the process units are piped to an overflow tank sized to hold 30 minutes

full works flow. A single vertical spindle pump with capacity of 126 m3/hr and a head of 6.5 m is

located in the tank which pumps the overflow at a controlled rate through a pipe of 200 mm diameter to

outside treatment plant area.

The service water system provides treated water to miscellaneous plant service such as chemical make-

up, wash down and fire fighting. The system is primarily located in the treated water pumping stationand consists of duty assist and standby pumps.

4.1.2 Scope of the Work

For Wasit subproject the length of transmission pipelines, service pipelines and static heads for all


37/180


drawings are constructed to cope with new subproject in Wasit. Finally the bill of quantities and

technical specifications for each item is revised and changed accordingly.

4.1.3 Design Criteria

The mechanical system is designed to meet the criteria specified below:-

- Colebrook-White formula is used for head loss calculations for all piping systems.

- 1.25 mm roughness coefficient is used for Ductile Iron pipe (cement lined) up to 20 years old.

- Pump discharge velocity (2-3) m/s.

- Pump discharge header velocity (1.5-2) m/s.

- DI pipe will adopt for all process yard pipe work to carry water and wastewater.

- Treated water pipeline is designed for ultimate capacity.

- The slopes for interconnecting pipes in site are adopted to fit the required invert for each unit.

- A wastewater pumps are sized to evacuate the tank in 2 hours.

- NPSH definition is used to calculate and check the cavitations for pump suction side.

- Natural ground level of Wasit site is 16.00 m.

4.1.4 Calculations

A computer program is developed for calculations of head losses in transmission and service pipelines,Net Positive Suction Heads (NPSH) and power required for the pumps in order to check the previously

selected pumps in standard design technical specifications. The results of the calculations are shown in

computer outputs.Based on the scope of the work, design criteria and the results of the calculations, the major changes in

standard design can be summarized as follows:-

1- The slopes for interconnecting pipes in the yard piping are calculated and adopted to fit the required

invert for each unit within the new layout and new drawings (13-231-2200/13-231-2201/ 13-231-2202/

13-231-2203 and 13-231-2204) have been constructed.

2-New dimensions for longitudinal sections of yard piping layout for process, wastewater and overflow

are calculated and new drawings (13-231-2205/13-231-2206 and 13-231-2207) have been constructed.

3- Based on new layout, new tables for manholes specifications (13-231-2208) and piping length,

diameters and fittings (13-231-2210) are formed.

4- Based on Wasit site layout a new drawing for yard service and potable water piping systems (13-


38/180


pumps heads selected in standard design. Therefore, the selected pumps for standard design will be

recommended and used for service and backwash pumping stations. The results of the calculation areshown in attached computer outputs.

7- The net positive suction heads for all pumping stations are calculated as shown in computer output,

checked and compared with the values of NPSH in technical specification of standard design. All the

values are within the selected range.

4.1.5 References

- All general arrangements

- Hydraulic design guide

- Drawing No. 13-231-2200 Wasit landscape pipelines

- Drawing No. 13-231-2201 Piping layout 1 0f 4




- Drawing No. 13-231-2205 Yard piping process pipelines

- Drawing No. 13-231-2206 Yard piping wastewater pipelines

- Drawing No. 13-231-2207 Yard piping overflow piplines

- Drawing No. 13-231-2208 Manhole schedule

- Drawing No. 13-231-2209 Thrust block schedule- Drawing No. 13-231-2210 Pipe schedule

- Drawing No. 13-231-2211 Service and potable water piping system

- Drawing No. 13-231-2212 Draniage system for wastewater and overflow water

- Treatment plant process output

- Fluid Mechanics, F. White, Second Edition

4.1.6 Sample of the Calculations

The results of all the calculations for yard piping, transmission pipelines head losses, net positive

suction heads for pumps and pumps power are represented and attached as a computer outputs for:-

- Head losses calculation for raw water pumps


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4.1.6.1 Head losses calculation for raw water pumps


40/180


4.1.6.2 Head losses calculation for treated water pumps


41/180


4.1.6.3 Head losses calculation for wastewater pumps


42/180


4.1.6.4 Head losses calculation for overflow pumps


43/180


4.1.6.5 Head losses calculation for backwash water pumps


44/180


4.1.6.6 Head losses calculation for service water pumps


45/180


46/180


4.2 Pump Station and Pipeline Hydraulic Transient Analysis

4.2.1 Purpose

Surges or transient pressure in a pressurized system are generally caused by a change of flow conditions

in the pipeline system. These changes cause waves to travel upstream and downstream from the pointwhere the change take place. The waves, in turn, cause increases or decreases in pressure as they travel

along the pipeline. Transient pressure is independent of the internal working pressure created by the

fluid in the pipeline; however transient pressure is proportional to the rate of change of flow conditionsand the pressure wave speed. Transient pressures must be considered during the pipeline and pump

station design to adequately protect the hydraulic system and ensure safety.Changes in flow conditions can result from either normal or abnormal hydraulic transient conditions in

a pumped system. Normal flow conditions changes may be caused by a change in pump operation suchas a normal pump startup or shut down, or by the normal opening and closing of valves in the system.

Abnormal flow conditions changes typically result from unplanned events such as power failure at the

pump station or a sudden/unexpected valve closure.

A sudden starting or stopping due to power failure are the most severe surge condition in a pumped

pipeline system. A rapid change in the flow conditions will take place at the pump station andimmediately propagate downstream of the pump. In a pumped system the pressures developed

following the pump start or failure within the system may exceed the limits that the system canwithstand casing damage to the system. A pressure control devices must therefore be provided in order

to control transients in the pipeline.

As part of this analysis, for both the raw water pump station and finished water pump station, a surge

control strategy has been recommended and sized to eliminate potential formation of high and vacuum

pressure conditions and resultant transient pressure conditions during a maximum flow uncontrolledpump station shutdown and pumps startup.

4.2.2 Transient Mathematical Model

In general two primary equations are used in predicting transient flow conditions for surge events, These

are based on Newton's second law of motion and on the continuity equation. The assumptions involved

and the derivation of the equations are found in the literature on fluid transients (Chaudhry, Wylie andStreeter, and Parmakian). When these equations are coupled, they form a pair of quasi-linear hyperbolic

partial differential equations in terms of two dependent variables, velocity and HGL elevation, and twoindependent variables, distance along the pipeline and time. The model uses the numerical approach

known as the Method of Characteristics to transform these equations into four ordinary differentialequations. In order to solve for the flow conditions at the end of time step at the two boundaries,

auxiliary equations are needed so that there are as many equations as there are unknowns. In other

d th ti f th b d diti t b d i th ti l f th t b


47/180


water pipeline systems.

4.2.3 Criteria and Analysis

The analysis performed included both the raw water and finished water pump stations. The assumptions

used to hydraulically represent the system and assess and size the surge control facilities are detailedbelow.

4.2.3.1 Raw Water Pump Station

The raw water pump station and pipeline system was modeled with the following assumptions:

Surge Events:The causes of the surge events are simultaneous power failure to pumps and simultaneouspump start up.

Pipelines: All pipelines are assumed to be ductile iron pipeline with a rated water working pressure of105m and an allowable downsurge and upsurge pressure allowances as follows:

Downsurge: To eliminate problems resulting from air admission to the system, no negative or sub-

atmospheric pressure is allowed along the pipeline.

Upsurge: Ductile iron pipeline has a surge pressure allowance of 70m for a total working plus surgepressure allowance of 175m.

Roughness Coefficient:The pipeline was assumed to have a relative roughness, , of 1.5 mm for a

Darcy Weisbach friction factor,f, of 0.026.

Source/Delivery Points:The model assumes the raw water pump station wet well as the supply point.

The wet well is modeled with water level of 16.77m and 13.75m. The delivery point is assumed to be theflocculation basin with a maximum and minimum water surface elevation of 20.837m and 20.775m,

respectively.Pump Station: Each pump is modeled with a rotational moment of inertia equal to the pump/motor

combination. Each pump rotational moment of inertia is derived from an empirical equation developedby A.R.D Thorley and published in Fluid Transients in Pipeline Systems

2

. The equation uses

horsepower and rotating speed to estimate moment of inertia. The raw water pump analysis assumes

three pumps running. Each pump produces 350m3/h for a total flow rate of 1000 m

3/h. The total moment

of inertia has been modeled as 4.0 kg-m2.

Pump Characteristics: Power failure at the pump station and pumps start are modeled to assess theworst-case surge condition. Pumps manufacturers usually supply the characteristics curve of normal

operation zone and very few of them supply the complete characteristics curve. If these curves are notavailable for a pump, then the curves for a pump of the same type with approximately the same specific

speed may be used (Chaudhry, Wylie and Streeter)


48/180


49/180

C. LOTTI & ASSOCIATI S.p.A. in coll aboration w ith CEB Baghdad University and Engicon

Pressure Wave Speed: A wave speed of approximately 1,160 m/s was utilized in the model. The

program performs minor adjustments to the wave speed to accommodate pipeline segments of differentlengths.

The head variation at the pump station due to pumps start and failure are shown in Figure (3). The

maximum pressure developed within the system reached a level of 66. No vacuum pressure occurred. A

minimum pressure level of 31.12m occurred at the station.

It is recommended that the system be equipped with a surge control system. Several mathematical modelruns were made with different air vessels sizes, the recommended surge control system is a 10 m

3hydro

pneumatic tank with 70% of the total volume initially charged with water and 30% charged withcompressed air. The results for the protected system are shown in Figure (4). The pressures are keptwithin acceptable limits at the station and along the pipeline.

It should be noted that both raw water and treated water analyses and control strategies that are

recommended should be verified once refinements to system control logic and equipment selection has

been made. Field tests are required to verify the variation of the pressures due to pump failure and pumpstart just when the raw and treated water stations are completed

4.2.4 Analysis Summary and Recomendations

Surge control facilities are required for both of the raw water and finished water systems. A surge tank of

a cross sectional area of 1.4m with a maximum top level of 25.5m is recommended to control the

transient pressures within the raw water system. .

A 10 cubic meter hydro-pneumatic tank is recommended to control the transient pressures within the

finished water system. Generally, hydro-pneumatic tanks of this size have a free water surface to

compressed air interface. The water surface level in the tank will fluctuate with system pressure and

therefore is continuously adjusted by a compressor and receiving tank. This type of system allowssignificant flexibility and will protect the system over a wide range of operating conditions. However,

general maintenance on the compressor is required to ensure operation. If the compressor is not

operational, the hydro-pneumatic tank will not protect the system during a transient event. An alternativeto the compressor system is an air bladder. The bladder is positioned within the tank during the

manufacturing process and after installation the bladder is inflated to a set pressure. This set pressure is

generally the higher end of the systems normal operating bandwidth. A bladder system does not provide

as much flexibility as a compressor designed system, but the inflated bladder system will maintain the set

pressure for an extended period of time without the need for constant adjustments. For a hydro-pneumatic tank this size periodic adjustments may be required depending on temperature and bladder

elasticity. Also, there are limited manufacturers of bladder hydro-pneumatic tank systems. If available

and cost feasible, a bladder tank is recommended.


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70


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Second Emergency Water Supply and Sanitation Project Wasit Detailed Design Report/fdDetailed Design Report c.a.: F249A51

0 25 50 75

Time (Sec.)

30

35

40

45

50

55

60

65

70

Head(m)

Head Variation due to pumps start

Head Variation due to pumps failure

Figure (3). Head variation at the finished water pump station without pressure control device.


60


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Second Emergency Water Supply and Sanitation Project Wasit Detailed Design Report/fdDetailed Design Report c.a.: F249A52

0 25 50 75 100 125 150 175 200

Time (Sec.)

40

45

50

55

60

Head(m)

Head Variation due to pumps start

Head Variation due to pumps failure

Figure (4). Head variation at the finished water pump s tation with pressure cont rol device.



54/180

4.3 Mechanical Equipment-HAVAC

4.3.1 Introduction

The standard design drawings for processing and non-processing buildings are reviewed and

selected to cope with the new subproject in Wasit. Also, all relevant HVAC system drawings

have been checked for cross references and changed to fit the new set of the drawings for

subproject in Wasit WTP.

Computer programs for calculations of cooling/heating loads and ventilation rates are

developed to check the standard design loads calculations. The cooling and heating loads

calculations for all spaces are performed. In addition, the required ventilation rates for pumps,

chlorination, chemical, rapid gravity filter and other halls are revised. Furthermore, the sizeand specifications of a scrubber unit for chlorinating hall is calculated and checked.

The work includes the design criteria and installation systems for air conditioning, heating

and ventilation for various spaces and will be as follows:

The air conditioning, heating and ventilation systems will be designed to meet the criteria

specified below:-

4.3.2 Design Criteria

4.3.2.1 Cooling

The air conditioned areas comprise the following spaces:-

- Non-process building

- Selected rooms in processing building

Inside design conditions will be:-- 23 oC Dry bulb temperature

- 50 % Relative humidity

- 20 % Fresh air makeup

4.3.2.2Heating

Heating areas comprise the conditioned spaces listed above and drum stores in the

chlorination stations.

- Conditioned spaces will be heated to maintain a

temperature of 21 oC.

D t ill b h t d t i t i


- Pipe galleries system


55/180

Pipe galleries system

6- Air changes/ hour

- Battery room extracts system


While mechanical ventilation areas comprise the following

- Generating hall

15 - Air changes/ hour

- Chlorinating building8- Air changes/ hour

- Pump halls


- Workshop system


Installation will be designed to operate continuously under limiting conditions for full range

likely meteorological conditions.

4.3.3 Systems

Different systems are used for cooling, heating and ventilation of various spaces in processing

and non-processing buildings of the Wasit water treatment plant. The systems for building

are as follows:-

4.3.3.1 Cooling system

An individual through the- wall split air conditioning units ( cooling/ heating ) will be

provided for individual rooms that are adequate for simplicity of air-conditioning smaller

spaces.

4.3.3.2 Heating system

Heating system will be provided to air conditioned areas by electric heater batteries within the

split air conditioning unit. In addition, duct inserted electric heaters will be provided in drumstore in the vicinity of the on-line drums and chemical building to maintain a temperature of

13 oC. Also, a local electric heater will be provided for workshop building.

4.3.3.3 Ventilation systems


In addition to the air ventilation specified for chlorinating station, a complete air cleaning


56/180

In addition to the air ventilation specified for chlorinating station, a complete air cleaning

system (scrubber unit) will be provided for removable of chlorine from contaminated exhaust

air following a chlorine leak in the drum store.

4.3.4 Sample of Calculations

4.3.4.1Non-processing building

A computer program is developed for the calculations of cooling and heating loads for all

spaces in the non-processing building . All the coefficients used in the calculations are based

on ASHRE standards with correction to our ambient conditions (latitude, month,

temperature,..etc.) and with the following conditions.

- Outside Summer: 46C Dry bulb and 23C Wet bulb.

- Outside Winter: 0C

- Daily temperature range = 19.2C

-Heat transfer coefficients

- Wall : 1.56 W/m2. C

- Roof : 0.65 W/m2. C- Glass : 5.7 W/m2. C

- Barrier: 3 W/m2. C

- Film coefficients

- Inside wall : 6.23 W/m2. C

- Outside wall: 22.7 W/m2. C

- An air change per hour is chosen as (20) for approved Air Cooler.

- All split units are manufactured for outside temp. = 35 C. Therefore, a correction is made to

estimate the actual load for ambient temperature of 50 oC.

- Load calculations for mechanical maintenance room

a- Heating load

- Heating load calculations showed a load of 11220 watt.

- Heat source from machines = 1800 w

- Net heat required = 9420 w

Therefore the heating load = 10000w


= 847 x 20


57/180

= 16940 m3/hr

= 9960 CFM

- (2) Nos. Evaporator Air Coolers with 5000 CFM each are selected.

- Load calculation for conditioned zones

A computer program is developed for calculation of cooling load for various zones in non-

processing building. The calculations are based on the design criteria and the correction

procedure to fit the ambient temperature of 50 oC. The computer output shows the details of

the calculations and cooling loads for other zones are shown in the attached table.4.3.4.2 Process buildings

The process buildings comprise pumps halls, rapid gravity filter, chemical, chlorine buildings

and other associated buildings. These buildings are provided with ventilation system thought

fan extraction units and sand trap filters. A computer program is developed for calculation of

ventilation loads for various spaces. The result of sample calculation is shown in computer

output. Loads for others zones are calculated and checked.

4.3.5 The Changed Drawings:

The drawing No. (13-299-5600) shows the technical information about the HAVC

equipment used in the WTP. The following units are not found in above drawing.

1- EUW-90-1003 & CU-90-1021

2- EUW-90-1002 & CU-90-1022

3- EUW-90-1003 & CU-90-1023

Electrical Building MCC

4- EUW-80-1001 & CU-80-1021 Chemical Building

5- EXF-80-1001

6- EXF-80-1002

So, these units are added in the table with their technical information ( split unit type,

capacity, power, voltage, phase .etc)

4.3.6 Bill of Quantities:

The bill of quantities is revised, checked and changed accordingly to fit the supplied

drawings.



58/180

Summary of Cooling Load Calculations for non-processing building

Building ZoneTotal Heat

(Watt)

Total Heat

(Btu/hr)

GTH

(Btu/hr)

Selected

Capacity

(Btu/hr)

Admini. 02 19628 66931 83664 3x30000

08 12568 42731 53413 2x30000

11 12009 40050 51186 2x3000012,13 12673 43088 53860 2x30000

14 11170 38092 47615 1x48000

17 22155 75548 94436 2x48000

Mainten. 07 8592 29298 36623 2x22300

09 7016 23924 29905 2x22300

10 3169 10815 13518 1x22300

3-BR 03 6533 22277 27846 1x3000006 4822 16464 20580 1x22300

07 5512 18812 23515 1x30000

08 4499 15355 19193 1x22300

10 5422 18505 23131 1x30000

11 4485 15307 19133 1x22300

2-BR B07 3918 13372 16715 1x22300

B03 5429 18529 23161 1x30000B06 3255 11101 13876 1x22300

B08 5248 17911 22388 1x30000

B11 5797 19709 24636 1x30000

2-BR A03 5762 19648 24560 1x30000

A06 5101 17409 21761 1x30000

A07 3918 13372 16715 1x22300

A08 3255 11101 13876 1x22300A10 5429 18529 23161 1x30000

Guard 02 3028 10334 12917 1x18000

05 2562 8744 10930 1x22300



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Ministry of Municipalities and Public Works Republic of Iraq 4/11/07Second Emergency Water Supply and Sanitation Project Wasit Detailed Design Report/fdDetailed Design Report c.a.: F249A

58

SUBJECT HVAC Sample of Calculations

Admin. Bui lding

Wasit WTP

ZONE NAME: off ice

COMPUTED DATE 30/6/2007

CHECKED DATE 06/01/2007

REFERENCES (3). Modern Air Conditioning Practice, 2nd Edition.

(1). ASHRAE FUNDAMENTALS 2001. (4). ASHRAE STANDARD 62-1989

(2). ASHRAE FUNDAMENTALS 1997.

DESIGN DATA (Ref. 1, Ref. 4)

Outside Design Air Temperatures

Maximum DB Maximum WB Minimum DB Daily DB Range

C F C F C F C F

50 122 23 73.4 24 75.2 19 66.2

Inside Design ConditionAir Conditioned Spaces Ventilated Spaces

Min. Temperature Max. TemperatureRelativeHumidity Min. Temperature Max. Temperature

C F C F % C F C F

23 73.4 30 86 50 8 46.4 40 104

BUILDING DATA

Surface Conductances and Resistances (Ref. 1, Table 1 on pg. 25.2)

Inside Surface

Surface TypeSurfacePosition hi (W/m

2.oC) Ri (

oC.m

2/W)

Horizontal 9.26 0.108Inside SurfaceVertical 8.29 0.121


O t id S f


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Ministry of Municipalities and Public Works Republic of Iraq 4/11/07Second Emergency Water Supply and Sanitation Project Wasit Detailed Design Report/fd

Detailed Design Report c.a.: F249A59

Outside Surface

Surface TypeSurfacePosition h

i(W/m

2.oC) R

i(oC.m

2/W)

Outside Surface summer Any 22.70 0.04

Thermal Properties

Thickness Conductivity Resistance Total Resistance Ud

x ka R

b R

c(

oC.m

2/W) W/m

2.oC

Item mm m. W.m/m2.oC

oC.m

2/W Rsummer Usummer

Gypsum Plaster 20 0.020 0.81 0.025Concrete 200 0.200 1.37 0.146

Cement Morter 20 0.020 0.72 0.028

Asphalet 1.000 97.5 0.010

Insulation Styrafoam 0.500 0.517 0.967

Sand 100 0.100 1.83 0.055

Roof

Concrete Tile 40 0.040 0.76 0.053

1.44 0.697

Gypsum Plaster 20 0.020 0.81 1.000Brick 25 0.025 0.72 0.035

Cement Morter 20 0.020 0.72 0.450Exposed Walls 1.65 0.606

ZONE DIMENSIONS

Length Width Height Volume

Room m ft m ft m ft m3 ft

3

Zone 8.50 27.9 4.50 14.8 3.50 ### 134 4727

COOLING LOAD CALCULATION BY CLTD/SCL/CLF METHOD FOR AIR CONDITIONED SPACES

Construction Data

Uwindow= 6.42W/m

2.oC (Ref. 1,

Table 4 on pg. 30.8)


Cooling Load from Heat Gain through Exposed Roof, Walls, Doors and Conduction through Galss

E ti UA(CLTD )


61/180



Equation: q = UA(CLTDCORR.)

Section

Net A m2 U-Factor (W/m

2.oC)

CLTDoC LM K

Corr.CLTD

oC Ref. for CLTD (Ref.2,Chap.28)

Roof 1 28 0.697 16 0.50 1.00 40 Table 30, Roof 1

NE wall 0 21 0.606 10 -0.50 0.85 35 Table 32, Wall 5

NW wall 0 40 0.606 8 0.00 0.85 24 Table 32, Wall 5

SE wall 1 29.75 0.606 12 0 0.85 39.4

SW wall 0 0 0.606 8 0 0.85 33 Table 32, Wall 1Where: Corr. CLTD = ((CLTD + LM) K + (25.5 - ti) + (tm - 29.4)) C

F=ventilation correction throughfalsh ciling

LM = alitute correction K = darkness correctiontm= mean outdoortemperature

Heat Load Through Glass

Conduction Cooling Load Through Glass

q = A U CLTDcorr

Section

Net A m2 U W/m

2.oC

Corr.CLTD

oC

Cooling LoadW

CoolingLoadBtu/h

Windows 6 6.42 27 1040 3547

Solar Cooling Load Through Glass

Equation: q = A(SC)(SCL)(SHGmax)

where SC= shading factor,SCL=solar cooling load factor SHGmax = soler heat gain

Windows Net A m2 SC SCL SHGmax

Ref. for SCL,SC and SHGmax (Ref. 2, Chapter

28)

CoolingLoad W Cooling Load Btu/h

NE window 0 0.64 0.81 445Table 36,

on pg. 28.50 0


NW window 0 0.64 0.81 445 0

SE i d 0 0 64 0 81 571 0


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SE window 0 0.64 0.81 571 0

SW window 6 0.64 0.81 571 1776

Cooling Load From People 1776

Equation:

qsensible= N(Sensible heat gain)CLF

Where qlatent = N(Latent heat gain)

N = number of people in space

Sensible and latent heat gain from occupancy - Ref. 1, Table 1 on pg. 29.4

CLF = Cooling load factor, by hour of occupancy - Ref. 2, Table 29 on pg.28.40

N Sensible Heat W latent Heat W CLF qsensible Wqlatent

WCooling

Load W

12 90 95 1.0 1080 1140 2220

Cooling Load from Heat Gain through Lights

Equation: q = WFulFsa(CLF)

W Factor Ful Fsa CLF q(W) q(Btu/h)

720 3.41 1 1.2 1 864 2946

Cooling Load from Infiltration Air

Infiltration through wall surface is neglected as insignificant.

To calculate the infiltration through doors, estimate 100 ft3per person per door passage (Ref. 2 on pg. 28.34).

Further estimate each door use is at 2 persons hour. 74.40 L/s

Qinfiltration= 2 x 100 /( 60 *2.118 =

qsensible= 1.22Q(to- ti)

qlatent= 2940Q(Wo-Wi)

Q L/s Factor t OcW kg(water)/kg(dry

air)qW

qBtu/h

74.40 1.22 27 2451 8357

74.40 2940 0.0010 219 746


Cooling load from equipment


63/180



Equipment

Cooling Load W Cooling Load Btu/h1 1000 3410

Summary of Cooling Load Calculations

itemSensible Cooling

Load W Latent Cooling Load W Sensible Cooling Load Btu/hLatent Cooling Load

Btu/h

Roof 780 2661

Exposed surfaces 1161 3958

Glass 3996 13626Equipment 1000 3410

People 1080 1140 3683 3887

Lights 864 2946

Infiltration 2451 219 8357 746

Subtotal 2451 1359 8357 4633

Grand Total Load 11332 1359 38641 9267

Summary of Cooling Load Calculations

RoomTotal CoolingLoad W Total Cooling Load 1.1 W

Total CoolingLoad Btu/h

Total Cooling LoadTon

Zone 12690 13960 47602 3.97

EQUPIMENT SELECTION

The load calculation is based on 46C temperaure outside condtion.

Equipment design is based on 35 C ambinent temperatureTotal Load will

be=4.96 Tons

Meter/Ton= 0.130

59503 Btu/h

Select Unit with 21950 Btu/h


Nos. of Units= 3


64/180



AIR REQUIREMENTS FOR AIR CONDITIONED SPACES

Sensible-Heat Factor (SHF):SHF = (Sensible Heat)/(Total Heat) = 0.89

Room Apparatus Dew Point (ADP):

Using the Psychrometric Chart with the room design condition of 32oC DB, 50% RH,

ADP = 11.5oC

Bypass Factor (BPF):

Assuming cooling coil bypass factor

BPF

=

0.1

Required Airflow (Qsupply): (Ref. 4)

Where RSH = room sensible heat

tr= room air temperature,oC

Qsupply = 0.897 m3

/s

Qsupply = 1900 Cfm 701CFM EachUnit

CFM/Ton= 383

Fresh Air= 190 CFM

( ) ( ) 1000ADPtBPF1822.1RSH

Qr

=


SUBJECT Sample of Calculations PROJECT NAME:


65/180

SUBJECT Sample of Calculations PROJECT NAME:

COMPUTED DATE 24/5/2007 Chlorinating B.

CHECKED DATE 28/5/2007 Drum StoreVentilation System Wasit WTP

REFERENCES

(1). ASHRAE FUNDAMENTALS 2001. (5). ASHRAE STANDARD 62-1989

(2). ASHRAE FUNDAMENTALS 1997.

wasit_detailed design report_updated.pdf

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