Example: quiz answers

CHAPTER 3 WATER SUPPLY SYSTEM - JICA

CHAPTER 3 WATER SUPPLY SYSTEM 3 - 1 CHAPTER 3 WATER SUPPLY SYSTEM General Components of the Priority Projects The stage I of the augmentation of Salaulim WATER SUPPLY Scheme (WSS) was selected as the priority projects from the urgency point of view because it has the most serious problem for WATER shortage, as described in Volume II Main Report: Master Plan. The project scale was set based on a careful examination of WATER demand, SUPPLY capacity, raw WATER availability and the PWD s financial capabilities. The selected priority projects are described below: Expansion of the Salaulim WATER Treatment Plant (WTP) by 100,000 m3/day, resulting in a total capacity of 260,000 m3/day Rehabilitation and Improvement of the Existing Salaulim WTP, which has a production capacity of 160,000 m3/day Construction of a 20,000 m3 Master Balancing Reservoir (MBR) at Sirvoi rock hill Installation of km of Transmission Mains, 150 to 1400 Rehabilitation of km of the Existing Transmission Mains, 1200 Construction of six Reservoirs Construction of five Pumping Stations Replacement of 4 units of Pumping Equipment at Verna Pumping Station Improvement of Operation and Maintenance, including installations of flow meters, float valves and flow control valves and

from cast iron, ductile iron or mild steel with cement mortar lining should be between 130 and 145. However, it is generally recommended that in the absence of specific data, a C value of 110 should be adopted. Therefore, a C value of 110 was adopted when designing the transmission system, including the existing pipelines. c. Hourly Peak Factor ...

Tags:

  Supply, Water, Cement, Water supply

Information

Domain:

Source:

Link to this page:

Please notify us if you found a problem with this document:

Other abuse

Transcription of CHAPTER 3 WATER SUPPLY SYSTEM - JICA

1 CHAPTER 3 WATER SUPPLY SYSTEM 3 - 1 CHAPTER 3 WATER SUPPLY SYSTEM General Components of the Priority Projects The stage I of the augmentation of Salaulim WATER SUPPLY Scheme (WSS) was selected as the priority projects from the urgency point of view because it has the most serious problem for WATER shortage, as described in Volume II Main Report: Master Plan. The project scale was set based on a careful examination of WATER demand, SUPPLY capacity, raw WATER availability and the PWD s financial capabilities. The selected priority projects are described below: Expansion of the Salaulim WATER Treatment Plant (WTP) by 100,000 m3/day, resulting in a total capacity of 260,000 m3/day Rehabilitation and Improvement of the Existing Salaulim WTP, which has a production capacity of 160,000 m3/day Construction of a 20,000 m3 Master Balancing Reservoir (MBR)

2 At Sirvoi rock hill Installation of km of Transmission Mains, 150 to 1400 Rehabilitation of km of the Existing Transmission Mains, 1200 Construction of six Reservoirs Construction of five Pumping Stations Replacement of 4 units of Pumping Equipment at Verna Pumping Station Improvement of Operation and Maintenance, including installations of flow meters, float valves and flow control valves and improvement of safety standard of WTPs for all 7 WSSs Establishment of Central Laboratory In addition to the above components, the PWD should develop the distribution network systems for expanded service areas where are newly covered by the priority projects in order to SUPPLY the increased capacity of 100,000 m3/day, which includes the installation of distribution pipelines and house connections. For the economic and financial analysis of the feasibility study explained in CHAPTER 9 of this volume, the costs for the analysis includes not only of selected priority projects listed above but also of the distribution network systems which will be improved by the PWD.

3 Staged Development Plan To meet the increased WATER demand, the WATER SUPPLY capacity of the Salaulim WTP will be expanded in two stages until the year 2025 as shown in Figure Under the first stage the 3 - 2 capacity will be expanded by 100,000 m3/day, to meet the daily maximum WATER demand in year 2018. The first stage of the Salaulim WSS was selected as the priority projects considering its urgency, importance and efficiency. The second stage also consists of an expansion of 100,000 m3/ day. 0500001000001500002000002500003000003500 0040000020052006200720082009201020112012 2013201420152016201720182019202020212022 202320242025 YearWater Quantity (m3/day)Treatment Plant CapacityDay Maximum WATER DemandStage I: 100,000 m3/dayStage II: 100,000 m3/day Figure Staged Development Plan for the Salaulim WSS Availability of the Raw WATER The raw WATER requirement for the existing WTP (which have a capacity of 160,000 m3/day) is 176,000 m3/day, including plant loss of 10 %.

4 On the other hand, the raw WATER requirement for the proposed WTP (which is a capacity of 100,000 m3/day) is 110,000 m3/day. Therefore the total raw WATER requirement of the Salaulim WTP becomes 286,000 m3/day. According to the Department of WATER Resources, Government of Goa, the raw WATER source availability from Salaulim Dam Reservoir for the Salaulim WTP is 380,000 m3/day as detailed in Volume II CHAPTER 5 Master Plan for WATER SUPPLY . This means that there is no problem and no limitation for the augmentation of Salaulim WTP from the viewpoint of raw WATER source. StageII:100,000 m3/day StageI:100,000 m3/dayPriority Projects3 - 3 Design Conditions WATER Treatment Plant (WTP) (1) Design Criteria of WTP The WTP is designed using the The Government of India, Manual on WATER SUPPLY and Treatment, CPHEEO, May 1999 as summarised in Table Any design criteria not stipulated in this Indian manual were based on the Japan WATER Works Association, Design Criteria for Waterworks Facilities, 2000.

5 Table Design Criteria of WTP TypeDesign ParameterCoagulationG value300s-1 (Rapid Mixer)Detention time30 - 60seconds60 - 300secondsRatio of impeller diameterto tank - FlocculationG value10 - 100s-110 - 75s-1 (Flocculator)Detention time15 - 20minutes20 - 40minutesWater - - or morem Clear distancebetween or morem Clear distancebetween end of baffle and or morem SedimentationSurface Loading30 - 40m3/m2 - (Clarifier)Detention Time2 - Length of tank (rectangular)30 - 100m Ratio of length to width3:1 - 5:13:1 - 5:1 Length of square tankup to 20m Diameter of tankup to 60m Depth of - 5m3 - 4(WatermInlet - than m/sWeir Loadingup to 300m3/d/m500m3/d/mRapid Sand FiltrationFiltration - 6m/hr5 - (Sand Filter)Number of filter beds(minimum)2 Maximum Filter areas up to 100m2up to 150m2 India*Japan**4 or 2 (small plants) * The Government of India, Manual on WATER SUPPLY and Treatment, May 1999 **Japan WATER Works Association, Design Criteria for Waterworks Facilities, 2000 (2) Design Flow of WTP Facilities WTP facilities are designed based on the daily maximum WATER demand and operation / maintenance process WATER (plant loss).)

6 In this study the plant loss is estimated to be 10% of the daily maximum WATER demand. Therefore the base flow of the WTP design is 110 % of the daily maximum WATER demand. 3 - 4 (3) Raw WATER Quality and WATER Treatment Process The raw WATER quality was considered for selecting WATER treatment processes, because iron and manganese were found in the raw WATER during the reconnaissance survey. Basically the rapid sand filtration process was adopted for WATER treatment process of the proposed WTP. (4) Rehabilitations and Improvements of WATER Treatment Facilities The existing WTP facilities are planed to be rehabilitated based on those life times. In general the design life for civil works is 50 years and the design life for mechanical and electrical equipment is 15 years. The proposed improvements to the existing facilities planned and these were based on plant safety, process control and the need for continuous WATER SUPPLY .

7 Plant safety is the most important aspect of the proposed improvements. The existing WTP does not have safety equipment especially for chlorine gas. Therefore safety and health improvements have been selected as part of the priority projects. The priority projects also include process control improvement for providing continuous WATER SUPPLY such as installing flow meters at inlet and outlet of WTP. Transmission SYSTEM (1) Proposed SYSTEM The transmission SYSTEM design is mainly based on the Manual on WATER SUPPLY and Treatment, Third Edition Revised and Updated, CPHEEO, MOUD, May 1999 . The key components are outlined below. a. Formula for Hydraulic Calculation: Hazen-Williams Formula There are a number of formulae available to calculate the velocity of flow ( Hazen-Williams formula, Manning s formula, Darcy-Weisbach s formula and Colebrook-White formula).

8 The Hazen-Williams formula is the best for situations involving pressure conduits. The formula is: V = C For circular conduits, the formula is restated as hf = L Where, V = Velocity (m/s) C = Hazen-Williams coefficient R = Hydraulic Radius (m) I = Hydraulic Gradient, hf/L hf = Friction Head Loss (m) 3 - 5 D = Diameter of Pipe (m) Q = Discharge (m3/s) L = Pipe Length (m) b. Hazen-Williams Coefficient (C Value): 110 for all materials The manual recommends that the Hazen-Williams coefficient (C value) for new pipes made from cast iron, ductile iron or mild steel with cement mortar lining should be between 130 and 145. However, it is generally recommended that in the absence of specific data, a C value of 110 should be adopted. Therefore, a C value of 110 was adopted when designing the transmission SYSTEM , including the existing pipelines.

9 C. Hourly Peak Factor: When designing the distribution SYSTEM hourly demand fluctuations must be considered. For example, during the night, people use less WATER , but in the morning and evening people use much more WATER . Figure shows the distribution flow to Lamgao at Bicholim City. This flow data was obtained during the first Phase Reconnaissance Survey. 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TimeFlow Rate (m3/hr) Figure Distribution Flow to Lamgao at Bicholim City, Bicholim Taluka In this case, the hourly peak flow is about times of the average distribution flow rate. Therefore, when designing the distribution SYSTEM an hourly peak factor of 2 was adopted as 3 - 6 well as the fluctuation pattern shown in Figure d. Software for Hydraulic Analysis: WaterCAD , Haestad Methods Inc The hydraulic analysis was conducted using a computer software program called WaterCAD for 500 pipes, which runs under the AutoCAD environment, Haestad Methods Inc.

10 It should be noted that since there is no recorded data or drawings of the existing transmission systems or details of the reservoirs, the modelling for the hydraulic analysis was prepared based on information obtained through interviews with the PWD s engineers, for the following SYSTEM components: routes, materials and diameters of transmission mains; and locations, capacities and WATER level of reservoirs. (2) Rehabilitation and Replacement of the Existing Transmission Mains The rehabilitation and replacement of the transmission mains will include the replacement of the following: all asbestos cement pipes which were installed before 1990; and 30 % of the all pipes that were installed before 1975. For reference, the proportions of different materials used in the existing transmission SYSTEM are shown in Figure 3 - 7 0%10%20%30%40%50%60%70%80%90%100% IronDuctile IronPSCMild Steel Source: Sector Status Study WSS Goa, 2004 Figure Percentage of Pipe Materials for each Scheme Reservoirs (1) Proposed Reservoirs New reservoirs will be proposed at expanded service areas to SUPPLY treated WATER .


Related search queries