Abstract

    We raise the problem and the impact we have had with the drinking water reserves and how it affects us the drinking water shortages and rationing. Although 75% of our planet is water, only 2.5% is potable water and 97.5% is salt water. Because this social problem for both daily living and for a state of emergency.

         This social concern comes to our attention and we propose an intelligent solution to this problem with the design of a Personal Solar Desalination System with power supply by battery with solar panel for recharging, for continuous process during the day and night. Through suction pump water, we collect salt water, passing through a first filtration system to remove impurities to a chamber for the desalination process where sensors control the amount of water that is sent by the pump. In this stage, salt water condensation, using electrical power produced from the sun, salt is removed and the clean water is collected in a second chamber where the water is exposed to UV light for bacterial removal and finally delivering drinking water

     We present our first proposal for the solution to this problem. we suggest a Purification and Desalination System.

Reverse Osmosis & Filtration Process

   The size of dirt particles contained in sea water varies widely. Therefore, sea water filtration needs more care than other fluids. A very special filtration solution is required to remove particles from 10 mm at one end of the spectrum down to 50 micron particles at the other. It requires filtration of both coarse and fine particles at the same time.

      Another important consideration in the filtration of sea water is the corrosive effect it has. Reverse Osmosis is a process in which dissolved inorganic solids (such as salts) are removed from a solution (such as water). This is accomplished by household water pressure pushing the tap water through a semi permeable membrane. The membrane (which is about as thick as cellophane) allows only the water to pass through, not the impurities or contaminates. These impurities and contaminates are flushed down the drain.

   Also to the filtration process we add a softener, alkaline filter and ultraviolet light to maximize the filtration process

Advantages and Disadvantages of RO (Reverse Osmosis) Systems

    I.  Advantages:

1. Performs a separation without a phase change. Thus, the energy requirements are low.
2. Systems are compact, and space requirements are less than with other desalting systems, e.g. distillation.
3. Equipment is standardized - pumps, motors, valves, flowmeters, pressure gages, etc. Thus, the learning curve for unskilled labor is short.
4. Systems are fully automated and designed to start-up and shutdown automatically through interlocks. Thus, RO plants usually require little labor.
5. Due to their modular design, maintenance is easy. Scheduled maintenance can be performed without shutting down the entire plant.
6. The modular design also makes expansion an easy option.

II.             Disadvantages:

   The applied pressure must exceed the osmotic pressure to obtain product flow and to separate the solute from the solvent. The maximum feed pressure for seawater devices varies from 800 -1000 psi, while the limit for brackish water varies from 400 -600 psi. Due to the high-pressure requirement (about 200 psi or more above the osmosis pressure) is usually not applicable for concentrated solutions.
    Because all membranes and devices are susceptible to fouling, the process usually cannot be applied without pretreatment.
 Feed streams must be compatible with the membrane and other materials of construction used in the devices. If the feed stream contains incompatible compounds, these must be removed in pretreatment, or another compatible device and/or membrane must be considered.

Specifications

 In FALL 2016, we present the redesigned proposal, the new design plan with the sample of one of the water pumps proposed for the design. In this presentation, we abound on the modifications of the system, the new goals and in a new scenario. In the same way, we present the new specifications to be able to satisfy the new goals. Additional consideration is given to the possibility of adding a cooling system as part of the process before filtering the water by osmosis.

   After the presentation, we begin to buy the materials to begin the construction of the cabinet, to begin the construction of the system and begin to perform the tests.

   Although we had initially contemplated making the cabinet or drawer with metal material, due to the change of design, to the increase of the dimensions contemplated and the high cost that represented the moment of the acquisition of materials, we obtained by a design of the prototype in wood.

   At the same time, the construction of the water heater is also started. In this design, we had to modify the glass heater because it did not resist the high temperatures. To solve this problem, we ordered the built tempered glass with our dimensions spec for the water heater design, which would allow us to reach high temperatures with solar irradiation.

PV System

 The Solar Desalination System battery bank should be 12v, sized to be able to store power for 8-12 hours a day of autonomy during night. After determining the size of the battery bank, we determine the number and capacity of photovoltaic modules needed to recharge the battery bank is calculated.

Design Diagram

Water Heater Plate

·         During a semi-sunny day of 1:00 pm - 2:00 pm, we were able to obtain readings from 70 degrees to 136 degrees Fahrenheits. In additional tests, we were able to get up to 172 degrees Fahrenheits in an hour.  

Cabinet Design

    The cabinet was designed with an angle of 18 degrees, for the installation of the photovoltaic module and solar heaters at an optimum angle that allows us to take advantage of the highest solar irradiation throughout the year.

Test

  We take water directly from the sea and another reading after passing through the multimedia filter.

     The reading of the raw water, directly from the beach, obtained a reading of 40% salt level. Once the initial reading is taken, we pass the sample through the first filter stage, the multimedia filter.                                        

     When reading this sample, after passing the stage of the multimedia filter, we obtained a reading of 30% of salt level, representing a reduction of 10% in salt levels of the sample.

Conclusions

          This project was a great learning experience because we had the opportunity to demonstrate the knowledge we learned during our years of studies. Likewise, it was a challenge for us because similar projects have had setbacks.

                                          Before                                    After

    As a final result, we concluded that we were able to desalinate the water. Although with a considerable increase in the budget cost. We were able to work the water with 40% of salt and eliminate 30%. Purifying water to 10% and within consumption levels. We were able to taste the water and although it had no salty taste, but we noticed a difference in flavor compared to the regular water processed for consumption.

    We consider that this prototype has potential to be improved, with some modifications in materials, integration of technology of live straw among other modifications as we suggest in our reports.