Solar Powered Rainwater Harvesting And Recycling

System
1st Engr. Amina Asif 2nd Bilal Tariq
Department of Electrical and Computer Engineering (ECE) Department of Electrical and Computer Engineering (ECE)
Air University, Air University,
Islamabad, Pakistan Islamabad, Pakistan
amina.asif@mail.au.edu.pk bilaltariqq1@gmail.com

3rd Zara Nasir 4th Muhammad Haseeb

Department of Electrical and Computer Engineering (ECE) Department of Electrical and Computer Engineering (ECE)
Air University, Air University,
Islamabad, Pakistan Islamabad, Pakistan
zaranasir456@gmail.com haseebgujjar05@gmail.com

Abstract—The potential to harvest rainwater is an important The most affected species by scarcity of water is humans.
technology that would remove the scarcity of clean and drink- Around 4 billion people, which is nearly two-thirds of the
able water. It can be used for many applications and allows world’s population, face severe water scarcity for at least one
autonomous devices on rooftops. This paper presents an idea
where solar energy was used as a source to power up the month of the year [1]. Also, 2.3 billion people live in water-
rainwater harvesting system and also makes it autonomous. At stressed countries, of which 733 million live in high and
the beginning of the paper, a comprehensive overview of the critically water-stressed countries [2]. Roughly two-thirds of
project that includes working using different components to store the world’s population may be facing water shortages by 2025.
and transport the collected water to a filtration unit. From the When there is a shortage of water, people can’t get enough
filtration unit, the clean water was presented as an output. The
paper results in fulfilling the requirement of drinkable water by water to drink, wash, or feed crops, and as a result, drought
filtering and then this water can be used for domestic as well as occurs. The other important factor is inadequate sanitation
commercial purposes. The paper concludes that this prototype of which is a huge problem for 2.4 billion people and can lead to
the rainwater harvesting and recycling system proves to be very deadly diarrhea diseases, including cholera and typhoid fever,
efficient and budget-friendly as it works on solar energy instead and other water-borne illnesses.
of costly external sources. These systems should be installed in
multiple places and other techniques should also be used to Multiple sectors are interlinked with water supply, and the
curb the shortage of water. At the same time, this technology shortage of water also affects those sectors. One of the major
is constantly improved and improvised to further enhance the sectors that is linked purely with water is agriculture because
system’s performance. 72% of all water withdrawals are used by agriculture. Shortage
Index Terms—solar, harvesting, recycling, energy, conversation of water has a major effect on the agriculture industry. As for
the other industries 16% of water is used by households and
12% by industries [3].
I. I NTRODUCTION
A. Data Analysis
Since life began on earth, all living creatures have required
some essential ingredients for their living. The one of the most The urgency to save water resources was deeply felt after
essential needs is water. Water is the basis of life on earth. the World Bank report which stated that the need for fresh
Without water, most living creatures cannot survive for long. water is doubling every 21 years and by 2050, 2 billion people
In the case of human beings, they cannot survive without water will live in areas with a shortage of water estimated by the
for more than three days. United Nations [4]. A study in 2006 was carried in the state
Nowadays, there is a shortage of resources on earth because of Texas to check the water levels and how an efficient system
of wastage and mismanagement of resources by human beings. can be installed to save water resources, the study found
As human beings have caused these problems, so they should out that the extraction of groundwater has increased over the
be responsible for solving them. If no solution will be devised, last 65 years, therefore, tests were conducted to check the
then these problems are going to have a major impact on solar-powered rainwater harvesting system and the effect of
the future. Some of the effects have started to show like the solar plates on the quality of water and health as through
rising level of the sea because of the melting of glaciers and manufacturing of photovoltaic cells humans are exposed to
increasing temperatures etc. toxic and carcinogenic compounds.
 A recent survey done in Australia for the use of water we analyze the situation of the water which is precarious to
harvested by rain showed the keen interest of people in watch as having the resources of water and dams in the capital
adopting this solution. Some people refuse to use the water as well still the need for the water per day is increasing as the
harvested from rain to use for some purposes, But the majority population is growing very rapidly.
of people are willing to use this approach to harvest water and According to the CDA [6], the authority currently supplies
even use it for cooking and drinking. about “70 mgd [million gallons per day], while the ideal
The people that does not support the idea of rainwater requirement is 110 mgd”, or around 35 gallons (132.5 liters)
harvesting are because cost-effectiveness is unlikely to be a per person per day but around 84.38 liters are being supplied
driver for rainwater tank adoption. Many people think that the into the city which makes it the shortfall of around 48
system that is to be installed for rainwater harvesting (RWH) litres per day per person and according to The World Health
will be costly and it is easy to use the main water supply Organization suggests that 20 liters per day are needed to take
for the source of water in the house. The water coming from care of basic hygiene and food needs, excluding bathing and
the main supply does not require any additional functioning laundry.
and people mostly think that RWH systems require the owner Let’s suppose that a family of 3 lives in a house of 30x30
to have some technical knowledge about the system. Also, ft so their shortfall is around 140 gallons and according to
many people are uncomfortable with the space required for a study by experts 32,000 gallons with 90% efficiency could
the installation of the system. easily be collected every year from a house comprising 2-3
1) Feasibility of rainwater in Pakistan: Rainwater harvest- rooms with a 30×30 ft roof (100 sq m) which 87 gallons per
ing systems can be very advantageous to Pakistan. Because day so it reduces the shortfall and it comes down on around
the monsoon season in Pakistan produces a lot of rain and that 50 gallons per day.
water can be preserved and filtered for better use. However,
II. L ITERATURE R EVIEW
the idea of rainwater harvesting is much less welcomed in
Pakistan due lack of awareness. Lahore one of the major cities The scarcity and wastage of water resources has become
of Pakistan is one of the most affected cities regarding water one of the significant issues that the world is facing. Multiple
scarcity. The population rate of Lahore is increasing day by ways are being used to prevent but since the 21st century, the
day thus increasing the water demand. The water resources in methods to store and harvest rainwater have been tested and
the city are facing a shortage due to this increase in population. applied in different regions of the world. Tanks are installed on
In the Monsoon season of Pakistan, the amount of rain in the rooftops or on the ground to collect the rainwater falling
Lahore can easily solve the problem if it is preserved. The through the pipes. These systems work on solar energy where
average annual rainfall in the city is 575 mm, varying from solar plates are also installed on rooftops. These systems do
300 mm to 1200 mm [5]. not require large-scale management and can easily be installed
2) Implementation in Pakistan: The Lahore Developing on the houses in isolation or are stand-alone systems. That
Authority (LDA) is the first institution in the country to adopt harvested water can be utilized for any purpose and can
rainwater harvesting to solve the problem. There are two main be cleaned through a filtration unit for drinking. There are
reasons to adopt this solution. Firstly, the main reason to multiple reasons that this is more compatible as compared to
adopt this solution is the increase in population of the city other solutions because making rainwater the source of water
as it is the main reason for the shortage of water in the city. to solve the problem of water scarcity is very easy. RWH is
Secondly, LDA has made some changes in the construction environmentally friendly.
clauses. These clauses demand the new residential construction There are two main methods of implementing the project:
in Lahore to build a specific area on the roofs of the houses • Surface runoff harvesting
for the preservation of the rainwater. • Rooftop rainwater harvesting
Adopting this approach is very good for the city and if 1) Surface runoff harvesting: This technique works best
similar actions are taken in other areas of Pakistan. This idea in urban areas where rainwater that is collected and used
of rainwater harvesting can be very helpful in most of the for specified water storage during rainstorms flows along the
cities facing the problem of water scarcity. Although Lahore ground. To store the surface runoff, the flow of tiny branches of
is a major area for the collection of rainwater as compared to rivers or reservoirs is changed. In ponds, tanks, and reservoirs
other areas around the country. The rainwater can be collected designed for this purpose, the surface runoff is held. To
in those areas and this can majorly affect the problem of water reduce evaporation, efficient and effective water conservation
scarcity in the country. The water collected from the rainwater techniques are used when storing rainwater. Many steps are
can be preserved properly and then it can be transported to In performed to maintain clean and hygienic water [7].
areas where there are no rains and extreme drought conditions 2) Rooftop rainwater harvesting: The Roof Top Rainwater
during some time of the year, like the desert areas of Pakistan. Harvesting Method is a technique that can be used in individ-
Pakistan, more than 70% of domestic water needs are met ual homes or schools to collect rainwater from roof catchments
by groundwater which is a freshwater source underground. But of residential or commercial structures, divert it, and then store
groundwater resources are being utilized and managed poorly, it in tanks. To meet daily demands such as flushing toilets,
and are being depleted at alarming rates. Just in Islamabad if washing machines, washing cars, gardening, showers, sinks,
 helped in supporting the autonomous structure of the project.
The sensors include a rainwater detection sensor that helps in
detecting the rainwater and when the rainwater detection sen-
sor is triggered the solenoid valve opens letting the rainwater
in. There are also water level detector sensors present in the
tank to detect the level of water, which are also linked with the
closing of the solenoid valve. As the tank is full, the sensor
representing the hundred percent filling of the tank triggers
the closing of the solenoid valve. The sensors representing
Fig. 1. Surface Run-off Rainwater Harvesting the fifty percent filling of the tank, when triggered start the
filtration process.
Relay is also present in the system which helps in switching
and baths, harvested rainwater can either be stored in a tank
the filtration unit on and off. Gravity helps in moving water
or transferred to an artificial recharge system [8].
from one storage unit to another for other purposes. When the
tank is half full the relay drives the DC pump and water moves
towards the filtration unit. After passing through the filtration
unit the water is stored in another tank for other applications.
A. Calculation of solar panels
For the selection of the correct solar panel or plate first of
all we have to check what size the battery we need.
Battery Calculation:
Relay:
P ower[one − Relay] = 0.125W atts (1)
P ower[three − Relays] = 0.375W atts (2)
Water Level Sensor: :
P ower[one − level − sensor] = 1.376W atts (3)
Fig. 2. Rooftop Rainwater Harvesting P ower[two − level − sensors] = 2.752W atts (4)

Why do we choose rooftop rainwater harvesting?: We chose ESP 8266:

rooftop rainwater harvesting system due following reasons P ower − required = 1.5W atts (5)
• Cost:
Solenoid Valve:
The project is highly cost-efficient as compared to a
runoff because it does not require a whole path for the P ower[one − valve] = 6W atts (6)
flow of water. Water can be stored directly into the tank P ower[two − valves] = 12W atts (7)
when rainwater is falling
• Easy implementation: UV Light:
It has easy implementation as it takes less area and the P ower − required = 10W atts (8)
components used are also smaller in size. The size of
the components like the storage tank is smaller which is T otal − load − W attage = 34.627W atts (9)
enough for one household. P eak − hours − of − sunshine = 3hours (10)
• No water distribution issues:
With each house having its system installed there will Total watt-hours required for the battery :
be no distribution issues because every house will have 34.627W atts ∗ 3hours = 103.88W h (11)
its own water supply. Issues created by some factors like
Solar Array Calculation: Power required by Solar Array :
the height of the ground etc. will be no more using this
approach. T otalW attHours 103.88W atts
= = 34.6275W atts
P eakhoursof sunshine 3Hours
III. M ETHODLOGY (12)
The Project “Solar-Powered Rainwater Harvesting and Re- Amps required by the Solar charge controller to be able to
cycling System” was an autonomous system powered by solar support a solar panel array of 34.6275W at 12 V are:
energy through which the microcontroller controls all the 34.6275W atts
= 2.885A (13)
components of the project. The sensors, connected with solar 12V
solar-powered microcontroller, also working on solar energy, DC Current required = 2.885 Amps For 34.6275 DC load.
B. Sensors the highest degree of acidity while 14 is the highest degree
There are multiple sensors involved in this project which are of alkalinity. We have used the Arduino PH sensor board and
rainwater detection sensors, and water level indicator sensors. PH probe for measuring the PH of the water collected after
1) Water detecting sensors: Water level sensors are present filtering. Here is the diagram of the Arduino pH sensor board.
at three levels. When the water starts filling all these sensors
would give feedback to the controller. When there is no water
in the tank the system will not proceed to the filtration process
but whenever water fills up to 50% or above it, it will start the
filtration process, and when the tank is 100% filled shed will
get close and filtration will continue. There are parallel plates
present at the surface of the water level sensor. The level of
the water is detected by increasing or decreasing conduction
between these plates. As the storage tank might be bigger, we
may need multiple sensors. Water detection sensor having a
model number WLSFA-2 has three pins Vcc, Gnd, and signal
pin. Following are the ratings:
Fig. 5. Arduino PH sensor board

PH probe working: A pH probe consists of two main parts:

• A glass electrode
• Reference electrode

Fig. 3. Water Detection Sensor

2) Water Level Sensor: A water level sensor is used to de-

tect the water levels and is made from the Mosfets comprising
four levels i.e.,25%, 50%,100%. Enchancement type Mosfets
were used to make the water level sensor as they turn on when
the voltage arrives at the gate and starts to work.

Fig. 6. pH probe and its characteristics

The pH sensor output depends on the pH of the solution being

measured as the ideal pH sensor produces 0V when the pH
Fig. 4. Water Level Sensor
value is at 7, it produces the positive voltage when the value
goes down and negative voltage when the pH value goes up as
3) PH sensor: The indicator of a solution’s acidity or it in effect from the hydrogen ions as soon as they touch the
basicity is the PH (potential hydrogen). It has no units and probe. The crux of all of it is pH of the solution is measured by
only measures the quantity activity of the hydrogen ions in a the voltage difference between the two electrodes connected
solution. to the probe of the pH sensor.
• A liquid is acidic if it contains a lot of hydrogen ions
(acids have a pH below 7). Filtration Unit
• A liquid is basic if it contains a low amount of hydrogen The filtration unit selected for the filtration of rainwater is
ions(alkali have a pH greater than 7). shown in the picture above. It was selected keeping in mind
• Substances that are neither acidic nor alkaline have a pH the required filtration needed for rainwater. It has 6 units in
of 7. one stand and 2 extra cartages for adjusting the PH levels
The pH scale is used to determine the degree of acidity of a and TDS amount. This unit consists of three basic filtration
substance. It is further divided into levels from 0 to 14, 0 is processes.
 transfers allow users to transfer code to devices that are not
associated with their PC. Webhooks allow users to do things
with outside help to control the task. Dashboard sharing allows
us to share that information.
Hardware Comapatibility: For using the Arduino IOT
cloud, some compatible hardware in the form of a microcon-
troller i-e. Esp32 or Esp8266 is required. In our system, we
utilized Esp8266 to show the values of water levels of impure
and pure tanks as well as the values coming from the pH
sensor which would tell the pH of the water in the pure tank
via an internet connection [10].
Process: A Thing is a device that can be connected to the
cloud and monitored and controlled. To create a Thing, the
user needs to first login or sign up for an Arduino account.
Fig. 7. Filtration Unit With UV Filter Once they have access to the Arduino IoT Cloud choose what
device to use and what Wi-Fi network to connect to. They can
also create variables that can be monitored and controlled. All
• On the right is the polypropylene sediment filter that is changes made to the device will be converted into a special
used to remove rust, mud, and dust particles from the sketch file. This file contains the code that will run on the
rain. The range of this cartage is 5 microns. device and communicate with the cloud. To add a device to the
• In the middle is the CTO coconut shell carbon filter which Thing, the user needs to configure it by installing the Arduino
is responsible for filtering chlorine and removing the odor Create Agent.
from the water. These filters also help in improving the Then the process of creating new variables in the Arduino
taste of water. the filtration range of this filter is 0.5 IoT Cloud starts, where the variables can be generated into a
microns sketch file and there are several data types to choose from, such
• On the left is the GAC coconut shell carbon filter which as int, float, boolean, long, and char. The user can choose the
also helps in filtering the chlorine from the water but its name, data type, update setting, and interaction mode. When
main purpose is to filter the volatile and semi-volatile or- a sketch is uploaded it will work but also update the cloud
ganic compounds present in the water. These compounds variables. If a variable with Read and Write permission is
are mainly found in gasoline smoke. It has a filtration created, a function is generated at the bottom of the sketch
range of 5 microns. file that executes the code within it each time the variable
Water enters the filter from the right and firstly it reaches changes. This allows most of the code to be left out of the
the polypropylene sediment filter onto the CTO coconut shell loop and only run when required. Dashboards are visual user
carbon filter and then to the GAC coconut shell carbon filter. interfaces that allow us to communicate with our boards over
After the water is passed from these filters the impurities the cloud. We can create home screen customization which is
present in the water are filtered out, then the water reaches the visual representation of the variables we create. We need to
the UV filtration unit. link home screen customization to our variables by selecting
a device and a variable that we want to link it with. Once
C. Internet of things linked, we can interact with the home screen customization
The IOT stands for Internet of Things where through the or monitor a value from a sensor that are PH and water level
internet physical devices ranging from sensors to software are sensor [11].
connected and used for exchanging and sharing data. The most
simple examples include Connected cars, Smart appliances, IV. I MPACT O N E NVIRONMENT A ND S USTAINABILITY
Connected security systems, and Smart agriculture equipment. The project would have a positive impact on the environ-
1) Arduino IOT Cloud: The Arduino IoT Cloud is a ment as it works through the use of natural resources i.e., solar
platform that allows us to create IoT projects with a user- energy therefore no production of a harmful material takes
friendly interface and for configuration and visualization [9]. place. Rainwater harvesting is a successful way to control the
The Arduino IoT Cloud allows users to interface the Arduino environmental damage caused by stormwater flowing away. By
to the web and control it from a distance. It includes informa- storing the majority of the water that flows on our roof, rain
tion checking, variable synchronization, planning, over-the-air harvesting keeps this water away from stormwater as a result
transfers, webhooks, Amazon Alexa backing, and dashboard it stays out of our waterways. There are also multiple other
sharing. Information checking allows the users to show the positive impacts of rainwater harvesting on the environment
values of sensors on the screen using the dashboard, while it protects our local water resources, makes our gardens more
variable synchronization allows connection between devices beautiful, and keeps us away from droughts, and floods. It
with coding. Planning allows users to plan responsibilities to helps to maintain healthy soils, and keep our gardens and
go on/off for a particular measure of time, and over-the-air plants healthy which helps to regulate local temperatures, limit
 Fig. 9. Proteus Simulation

The water level sensor has four levels i.e., 25%,50%,75%,

Fig. 8. System Interface
and 100% level. As soon as the water level reaches 25%
the water would move from impure to pure tank through the
filtration unit and then that filtered water is stored in the pure
the effects of wet and dry spells, and control impacts of climate water tank where another water level sensor is installed to
change. check its level as well.
Rainwater harvesting can also limit the environmental effects The filtration unit would continue to work as soon as the
of urbanization on stormwater drainage systems. Rainwater water level is less than 100% but as soon as it reaches the
harvesting should be regarded as an essential element of global level of 100% in the pure water tank ,the valve of the tank
water management systems. There is a clear need for archi- would close and the filtration unit would also automatically
tects, designers, and builders to consider allowing rainwater stop as well.
harvesting into new projects as traditional water resources
are becoming less viable. The growth in living especially B. Hardware
smaller houses, for example, generates exciting opportunities
to install rainwater tanks and other features of this system on
the rooftop. Building industry professionals should be skilled
and know about smart homes.
As far as the sustainability of the system is concerned Rainwa-
ter harvesting (RWH) is the most sustainable method, which
could be easily be utilized for purposes both in residential
and commercial uses. This could help to reduce the pressure
on the constant need for fresh water which would increase
the green living. The sustainability of this system can further
be enhanced by checking several water quality parameters of
collected rainwater. Several parameters were included in the
analysis, pH, bacteria and germs presence, etc.

V. R ESULTS AND D ISCUSSION

A. Simulation Fig. 10. System Hardware
In the Proteus simulation, the whole system was integrated
and channelized for the working of the system. The first phase
of the system is the DC supply for the system using solar VI. C ONCLUSION
power. To make the system more reliable and feasible solar
power is utilized for its running. This paper was a collective team effort that resulted in
Initially, it works DC supply from the battery charged from addition to something useful in society. The purpose of this
solar energy to Arduino, Esp8266, solenoid valve, relays, project is to have drinkable water in the areas where there is a
and sensor respectively. The process starts to work when the water shortage and to Reduce the need for imported water.
rainwater sensor senses the water the electric valve opens and The problem of water scarcity is solved through rainwater
the tank starts to store impure water which is integrated with harvesting and storing it to filter and make it drinkable and to
the water level sensor as it would indicate when to start the use it for any other purpose like drinking, gardening, washing
process of the filtration. cars, firefighting, etc.
 VII. F UTURE W ORKS vol. 2, no. 1, pp. 1–4, 2018.
The system in the future can further be improvised and
[10] A. Qutieshat, R. Aouididi, and R. Arfaoui, “Design
can be improved using any device or computer which can
and construction of a low-cost arduino-based ph sensor for
predict the forecast and weather conditions. Further, a more
the visually impaired using universal ph paper,” 2019.
efficient method so that only rainwater is stored and filtered.
An automatic track and trace can also be interfaced with this
[11] P. P. Ray, “A survey of iot cloud platforms,” Future
system to maintain its cleanliness. The capacity issue can be
Computing and Informatics Journal, vol. 1, no. 1-2, pp. 35–46,
resolved by using bigger tanks but it also must not exceed the
desired requirement

R EFERENCES
[1] M. M. Mekonnen and A. Y. Hoekstra, “Four billion
people facing severe water scarcity,” Science advances, vol.
2, no. 2, p. e1500323, 2016.

[2] U. Water et al., Progress on change in water-use

efficiency: Global status and acceleration needs for SDG
indicator 6.4. 1, 2021. Food Agriculture Org., 2021.

[3] S. Kanwal, H. Gabriel, K. Mahmood, R. Ali, A.

Haidar, and T. Tehseen, “Lahore’s groundwater depletion-a
review of the aquifer susceptibility to degradation and its
consequences,” University of Engineering and Technology
Taxila. Technical Journal, vol. 20, no. 1, p. 26, 2015.

[4] O. Rashid, F. Awan, Z. Ullah, and I. Hassan, “Rainwater

harvesting, a measure to meet domestic water requirement a
case study islamabad, pakistan.” in IOP Conference Series:
Materials Science and Engineering, vol. 414, no. 1. IOP
Publishing, 2018, p. 012018.

[5] R. Zakharchenko, L. Licea-Jimenez, S. Pérez-Garcıa, P.

Vorobiev, U. Dehesa-Carrasco, J. Perez-Robles, J. Gonzalez-
Hernandez, and Y. Vorobiev, “Photovoltaic solar panel for a
hybrid pv/thermal system,” Solar Energy Materials and Solar
Cells, vol. 82, no. 1-2, pp. 253–261, 2004.

[6] K. Amara, A. Fekik, D. Hocine, M. L. Bakir, E.-

B. Bourennane, T. A. Malek, and A. Malek, “Improved
performance of a pv solar panel with adaptive neuro fuzzy
inference system anfis based mppt,” in 2018 7th international
conference on renewable energy research and applications
(ICRERA). IEEE, 2018, pp. 1098–1101.

[7] Gwenzi, W., Nyamadzawo, G. (2014). Hydrological

impacts of urbanization and urban roof water harvesting in
water-limited catchments: a review. Environmental Processes,
1, 573-593.
[8] Patel, U. R., Patel, V. A., Balya, M. I., Rajgor, H.
M. (2014). Rooftop rainwater harvesting (RRWH) at SPSV
Campus, Visnagar: Gujarat-A case study. Int. J. Res. Eng.
Technol, 3(04), 821-825.
[9] T. Majaw, R. Deka, S. Roy, and B. Goswami, “Solar
charge controllers using mppt and pwm: A review,” ADBU
Journal of Electrical and Electronics Engineering (AJEEE),