Project Name : Treatment of Sewage/Impure Water Using Solar Energy
Theme Name : Natural Resource & their Conservation
Objective: The objective of the experiment is to treat and purify sewage/impure water by the process of distillation using sunlight. This method does not use any kind of conventional source of energy. The presence of sunlight in abundance makes this model both ecologically and economically viable. This model aims at improving the existing sewage/impure water treatment plants by developing an alternate way of water purification.
Scientific Principle Involved: The principle of this model is basically divided into two parts. The first part uses the principle of filtration and adsorption based on the difference in the particle sizes. The second part uses the principle of solar concentration using a concave mosaic mirror. The concentration of sunlight creates enough heat required to distill the sewage/impure water. The distillation flask is placed at the focus of the mirror which creates a temperature of about 160 °C.
Materials Used:
The Mosaic Mirror: Constructed using a dish antenna on which several pieces of plane mirror each measuring 2”x2” are stuck using adhesives forming a concave mosaic mirror.
Support system: The support system comprises of a stand made out of pipes for the filtration unit, 2 wooden planks for filtration bottles and mosaic mirror respectively.
Filtration unit: Comprises of 2 filtration bottles in which activated charcoal and sand are placed respectively, to act as natural filters.
Distillation unit: Comprises of a specially designed flask made of borosil glass with a rubber cork held into place with the help of an iron stand. The spout of the flask is attached a rubber pipe which is connected to a condenser which is again connected to the mouth of a flask which acts as the collector.
Extra Materials Used: Rubber pipes, bottles, M-seal, tape, rubber corks, etc.
Working of the Model: The model consists of following units: 1) Filtration unit; 2) Distillation unit; 3) Condensation unit; 4) Solar Concentration unit.
The working of the model begins by pouring of sewage/impure water into the filtration unit, which is placed at a certain height. The filtration unit consists of 2 step filtration, by activated charcoal and by sand. After filtration, the water passes through transparent rubber pipes and flows into the distillation unit. The distillation unit comprises of a distillation flask, whose base is placed at the
principle focus of the solar concentration unit for heating by solar concentration. The solar concentration unit consists of a mosaic concave mirror to which is fixed an iron rod for holding the distillation unit; and a stand. After heating the pure water leaves the distillation unit in the form of vapor leaving behind the impure residues in the distillation flask, and then enters the condensation
unit. We finally collect this water in the collector placed at the bottom of the solar concentrator.
Research and Findings:
Few important parameters for testing purity of water:
pH, Total Dissolved Solids (TDS), Biochemical Oxygen Demand, Total Hardness, E-Coli, Coliform Organisations
As per the KSPCB, distilled water satisfies the above parameters:
pH – 7, TDS – <5, BOD – Nil, Total Hardness – Nil, E-Coli – Nil, Coliform Organisms – Nil
This water can be tested from KSPCB authorized centres like EnviPro for further verification.
Utility: This model is an improved version of the current sewage/impure water treatment plant. As this model uses solar energy, it does not require any kind of fuel. This model can be used in industries, government projects, apartments etc. for the recycling and purification of sewage or impure water. The purified water can be used in automobiles, laboratories, etc. The mineral residues left after distillation can be used for industrial purposes. The organic residues left can be
used as manure for agriculture.
Further Scope for Improvement:
1) Model can be made automatic to reduce manual labour.
2) Model could be improved so as to accommodate larger volumes of water.
3) The concave mosaic mirror can be converted to a large parabolic reflector for efficient and faster heating.
4) The tracking system can be made automatic so as to keep track of the Sun.
5) Water can be mineralised so as to make the water potable.
6) Apparatus can be made of copper and can be blackened to increase the heating.
Name of the School: CMR National Public School, Bangalore.
