COPY RIGHTS : TO AVOID COPYRIGHT VIOLATIONS, ALL POSTS ARE SHOWN ALONG WITH SOURCES FROM WHERE ITS TAKEN. PLEASE CONTACT ME IN MY EMAIL SALEEMASRAF@GMAIL.COM , IF YOU ARE THE AUTHOR AND YOUR NAME IS NOT DISPLAYED IN THE ARTICLE.THE UNINTENTIONAL LAPSE ON MY PART WILL BE IMMEDIATELY CORRECTED.

I HAVE SHARED ALL MY PRACTICAL WATER TREATMENT EXPERIENCES WITH SOLVED EXAMPLE HERE SO THAT ANYBODY CAN USE IT.

SEARCH THIS BLOG BELOW FOR ENVO ,COMPACT STP,ETP,STP,FMR,MBBR,SAFF,IRON,ARSENIC,FLUORIDE,FILTER,RO,UASB,BIO GAS,AERATION TANK,SETTLING TANK,DOSING,AMC.

SEARCH THIS BLOG

Wednesday, August 31, 2016

How to design a rain water harvesting system RWH CASE STUDY : TAJ SATS AIR CATERING LTD,IGI AIRPORT COMPLEX, NEW DELHI



manual on rain water harvesting Central ground water board

+++++++++++++++++++++++++++++++++++

web site for rain water harvesting

1.                INTRODUCTION

In spite of astonishing achievment in the field of science and technology, nature remain to be a mystery for human being . Though water is obtained through desalination, artificial rain by cloud seeding etc. the shortage of water even for drinking purpose is a perpetual phenomenon throughout the world,in most of the cities , the water supply sector is facing a number of problems and the income in population in urban area have resulted in exploitation of water resources to the extremes .  Fresh water sources are being heavily exploited to meet the demands of urban population . Failure of monsoon fail to meet the ever increasing demands and ground water reserves are tapped , often to unsustainable levels. Unplanned and uncontrolled extraction of ground water would disturb the hydrological balance . Hence it is necessary to take up measures to conserve and management of the renewable water sources in all possible ways. Ground water recharge by rain water harvesting (RWH) is the simple and cost effective way.

Rooftop Rain Water Harvesting is the technique through which rain water is captured from the roof catchments and stored in underground reservoirs. Harvested rain water can be injected to sub-surface ground water aquifer by adopting artificial recharge techniques to increase the level of ground water. The Main Objective of rooftop rain water harvesting is to stop the depleting water level of ground water and make water available for future use. Capturing and storing rain water in underground tanks for use is particularly important in dry land, hilly, urban and coastal areas. In alluvial areas energy saving for 1m. rise in ground water level is around 0.40 kilo watt per hour.                                                                                       
                  
Need for Rooftop Rain Water Harvesting
1. To meet the ever increasing demand for water
2. To reduce the runoff which chokes storm drains
3. To avoid flooding of roads
4. To augment the ground water storage and control decline of water levels
5. To reduce ground water pollution
6. To improve the quality of ground water
7. To reduce the soil erosion
8. To supplement domestic water requirement during summer, drought etc.up

Advantages of Rain Water Harvesting
1. Provides self-sufficiency to your water supply
2. Reduces the cost for pumping of ground water
3. Provides high quality water, soft and low in minerals
4. Improves the quality of ground water through dilution when recharged to
ground water
5. Reduces soil erosion in urban areas
6. The rooftop rain water harvesting is less expensive
7. Rainwater harvesting systems are simple which can be adopted by
individuals
8. Rooftop rain water harvesting systems are easy to construct, operate and
maintain
9. In hilly terrains, rain water harvesting is preferred
10. In saline or coastal areas, rain water provides good quality water and
when recharged to ground water, it reduces salinity and also helps in
maintaining balance between the fresh-saline water interface
11. In Islands, due to limited extent of fresh water aquifers, rain water
harvesting is the most preferred source of water for domestic use
12. In desert, where rain fall is low, rain water harvesting has been
providing relief to people


A Few Benefits of Water Harvesting
A Foot of Rain Per Year
On average, Pima County receives about 12 inches, or one foot, of rain per
year. As our community has developed, large areas of land have been changed
from native desert vegetation to more impervious surfaces such as houses,
driveways, roads and parking lots. When it rains, these impervious land
areas shed a greater amount of rainfall, which in turn results in more
runoff in area washes and the possibility of local flooding problems.
So Many Benefits for so Little Effort
While many people may not realize it, those few inches of annual rainfall
are a valuable resource. Harvesting rainwater not only helps reduce the
possibility of flooding, but it also decreases the community's dependence on
groundwater for domestic uses. Unlike groundwater, however, rainwater is
remarkably pure with virtually no dissolved salts or minerals. Because of
this, rainwater is perfectly suited for landscape irrigation, use in
evaporative coolers, washing and many other home applications. Using
harvested water to irrigate plants, for instance, flushes salt buildup from
the soil and produces vigorous, healthy plants. When rainwater is used in
evaporative coolers or for washing needs, hardness deposits do no accumulate
and there is no problem with soap scum. Imagine not having to scrap your
evaporative cooler every year! Harvested water may also be used for personal
consumption, but it must be filtered and treated prior to use. By reducing
runoff and using rainwater that falls on your property, you can put a
valuable water resource to work around your house and yard.


Here's Just a Few Benefits from Harvesting Water:
· Conserves valuable groundwater and reduces your monthly water bill.

· Reduces local flooding and drainage problems.

· Flushes salt buildup from soils-- your plants and landscaping will notice
the difference!

· Decreases landscaping and property maintenance needs.

· Provides excellent quality water for many home uses.


ENVO CASE STUDY : TAJ SATS AIR CATERING LTD,IGI AIRPORT COMPLEX, NEW DELHI
Roof Top harvesting potential
In order to study the rooftop harvesting potential, the total roof-top area was calculated and is depicted in table (1). In this method, the roof-top areas of various buildings in Taj Sats Air Catering Ltd, New Delhi was calculated and 25 mm of rainfall was observed in 15 min time. So, we got the roof-top potential of each building (depicted in table (1)).


Total quantity of water
to be collected (cu.m.) =
Roof Top Area (Sq.m.)
x Average Monsoon Rainfall (m) x 0.8


ANNUAL TEMPERATURE & RAINFALL CHART FOR  NATIONAL CAPITAL REGION OF DELHI

MONTHS
MAX
MIN
RAINFALL

JANUARY
21
07
25

FEBRUARY
24
10
22

MARCH
30
15
17

APRIL
36
21
07

MAY
41
27
08

JUNE
40
29
65

JULY
35
27
211

AUGUST
34
26
173

SEPTEMBER
34
25
150

OCTOBER
35
19
31

NOVEMBER
29
12
01

DECEMBER
23
08
05







Availability of Rain Water through Rooftop Rain Water Harvesting

Rooftop Area (sq.m.)
Rainfall (in mm)
100
200
300
400
500
600
800
1000
1200
1400
1600
1800
2000

Volume of Water (in cum)
20
1.6
3.2
4.8
6.4
8
9.6
12.8
16
19.2
22.4
25.6
28.8
32

30
2.4
4.8
7.2
9.6
12
14.4
19.2
24
28.8
33.6
38.4
43.2
48

40
3.2
6.4
9.6
12.8
16
19.2
25.6
32
38.4
44.8
51.2
57.6
64

50
4
8
12
16
20
24
32
40
48
56
64
72
80

60
4.8
9.6
14.4
19.2
24
28.8
38.4
48
57.6
67.2
76.8
86.4
96

70
5.6
11.2
16.8
22.4
28
33.6
44.8
56
67.2
78.4
89.6
100.8
112

80
6.4
12.8
19.2
25.6
32
38.4
51.2
64
76.8
89.6
102.4
115.2
128

90
7.2
14.4
21.6
28.8
36
43.2
57.6
72
86.4
100.8
115.2
129.6
144

100
8
16
24
32
40
48
64
80
96
112
128
144
160

150
12
24
36
48
60
72
96
120
144
168
192
216
240

200
16
32
48
64
80
96
128
160
192
224
256
288
320

250
20
40
60
80
100
120
160
200
240
280
320
360
400

300
24
48
72
96
120
144
192
240
288
336
384
432
480

400
32
64
96
128
160
192
256
320
384
448
512
576
640

500
40
80
120
160
200
240
320
400
480
560
640
720
800

1000
80
160
240
320
400
480
640
800
960
1120
1280
1440
1600

2000
160
320
480
640
800
960
1280
1600
1920
2240
2560
2880
3200

3000
240
480
720
960
1200
1440
1920
2400
2880
3360
3840
4320
4800


Design Of Rain Water Harvesting System By Injection Well Method
The rainwater harvesting system suggested for Taj Sats Air Catering Ltd, New Delhi is as follows :-


6.4.1   Design For Roof Top Area
Rooftop potential (really a good source of unpolluted water) as depicted in table (1) is of nearby buildings taken together. The volume of water is collected from rooftops and conveyed to the injection well through main pipes in such a way that it is economical and optimal use of the ingredients used in easy flow of the water. The injection well should be so located so that it comes into crest of the land and does not fall on the trough. For this purpose such a portion of the area be used which is not required for any further construction in future.

This requires a thorough study on the basis of work-study principles-flow diagrams, ground contours, ground water contours, foundation details (injection well should be min 10 m away from any foundation). Layout Plan of Taj Sats Air Catering Ltd, IGI , Airport Authority Complex, New Delhi, sewage pipes, sewage pumps, Electrical fittings and other important under ground installations would also be taken into consideration.
On the basis of the volume of water flowing through the main pipes in the injection well, the injection well’s parameters were fixed and depicted in table (3).

6.4.2 Interconnecting pipes:
a)     Drain Pipe : The rain water collected in the roof is allowed to come down to ground level via drain pipes.Drain pipes are made of MS .
b)     Inflow Pipe network : The water coming down from roof via drain pipes is led to the inflow pipe network placed on ground level. The pipes of the network are joined together at all intersecting points by junction boxes provided. The pipe network is made of MS and having dia 6 inches. The pipes are laid with proper slope to the recharge pit. The pipe ends are joined together by means of flanzes.
6.4.3 Recharge pit

1. Two Recharge pits as per required volume as indicated in the above chart are constructed to recharge the shallow aquifer. 2. After excavation, the pit is refilled with boulders and pebbles at the bottom followed by gravel. 3. The collected water from the rooftop is diverted to the pit through a drain pipe and inflow pipe network . 4. Recharge water is filtered through the pit. 5. The upper layer of material in the  pit should be removed and replaced every year after rainy season.

Recommendation
Since the rainwater harvesting system is used for the groundwater recharging in the trough zone of the aquifer system by virtue of which the aquifer system of the study area will be saturated and as a result the failure of the tubewell will be stopped and tubewell life will be enhanced . The groundwater quality will certainly be improved due to more percolation of rainwater other than the natural course of action of percolation, through the two Injection wells installed.  It is  recommended that, monitoring system for the impact of rainwater harvesting for groundwater recharging should  be installed for the periodic assessment to be carried out in the study area in order to monitor the improvement of the groundwater quality and potential of the study area. The installation of the two injection wells as per location given in map  are executed for the roof top harvesting .The details of the Injection Wells are mentioned in table no.3 and the strata  encountered are given in the figures.
SUMMERY OF THE PROJECT::
1.                                                                                                      Two  Injection Wells in the study area  are installed for  Rainwater Harvesting for Groundwater Recharging,
2.                                                                                                      Calax / Reverse Rotary rig is used for drilling .
3.                                                                                                      MS pipes are used for interconnecting the roof with injection wells.

4.                                                                                                        Junction boxes are provided between drain pipe coming from roof to interconnecting pipes going to injection wells.

DATA REQUIRED FOR DESIGN




CALCULATION SHEET


CALCULATION FOR A SMALL HOME

COMPLETION CERTIFICATE OF THE PROJECT