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Greywater Purifier Desalination System

The post explains a simple grey water purifier, desalination design arrangement which can be used for recycling greywater into pure usable distilled water completely free of cost through solar heat concentration.

 The idea was requested by Mr. Luis Gomes Machado

Technical Specifications

I wrote to you on a forum last week about your idea for a desalinator. I would want to explain you my need and try to understand if we can make your idea doable.

I have an average need of 25 m3 (25 000 L) of water per month.

I am implementing a grey water re-usage from showers, washing machine and sinks, to toilets filtering this grey water through 2 sand filters.Recen studies in Colombia state that 40% of water usage is on toilets which I would save this way 10 m3 (10 000 L)I will then have a need or the remaining 15,000 L per month.

I have 8 Air Conditioning mini splits that produce 40 L per day each one. so...8 x 40 L x 30 days = 9 600 L per month I will need to find an extra way of obtaining 5 400 L per month of water.

Lets round up and say 200 L per day. do you think that your system is able to produce 200 L of desalinated water per month? How? What do you suggest?

I live in the Colombian Caribbean with an average temperature of 30ÂșC and almost no rain per year thanx in advance for your advice

Best Regards/Cordial Saludo

Luis Gomes Machado

The Design

Whether its Greywater or sewage, any form of impure water can be easily converted into a pure distilled water using solar heat which is amply available on this planet, especially within the tropical areas where sun heat is abundantly accessible.

I have already discussed a similar concept for desalinating sea water in large quantities and also how to make drinking water from sea water, the present greywater purifier, desalination design is implemented using the same theory of evaporating/cooling waste water through concentrated sun rays.

The following simple arrangement using a concave polished metal and the associated mechanisms can be used for concentrating sun rays at the calculated focal points.

simple arrangement using a concave polished metal for concentrating sun rays

As can be seen in the above diagram, sun rays incident on the polished concave mirror or sheet is reflected back at an inward 45 degrees to concentrate over the centrally elevated pipe, running throughout the length of the sheet.

The concentrated sun rays over this pipe can be expected to be extremely high in temperature, in the region of around 150 C, enough to force water to evaporate.

Since the intended greywater is passed into the pipe, as indicated, this water inside the pipe is bound to reach its boiling and evaporation point quite quickly releasing water vapor from the other side of the pipe, which may be collected and condensed in an overhead tank.

This collected water can be expected to be 100% clean and could be used for any desired household work, such as for washing clothes, bathing, washing utensils etc.

Many such concave mirror based greywater purifier, desalination system could be installed within a given premise for implementing the above discussed conversion of waste water to clean water through solar heat, completely free of cost, and without using any electricity.

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  1. Sir,
    I have a 6V 4.5Ah Lead Acid Battery. Please help me how to build a circuit to charge it ...? Are there any circuits available in the market so tat I can directly buy?


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