Can anyone give a good concept or method for rainwater harvesting and purification?

Question

If you have a reference, please include it.

Answer 1

Purification in a chemical context is the physical separation of a chemical substance of interest from foreign or contaminating substances. The following list of chemical purification methods should not be considered exhaustive.

-Filtration is a mechanical method to separate solids from liquids or gases by passing the feed stream through a porous sheet such as a cloth or membrane, which retains the solids and allows the liquid to pass through.

-Centrifugation separates solids from liquids, or separates two immiscible liquids, on the basis of density.

-Evaporation is used to remove volatile liquids from non-volatile solutes which cannot be done through filtration due to the small size of the substances.

-Extraction removes an impurity, or recovers a desired product, by dissolving it in a solvent in which other components of the feed material are insoluble.

-Crystallization separates a product from a liquid feedstream, often in extremely pure form, by cooling the feedstream or adding precipitants which lower the solubility of the desired product so that it forms crystals. The pure solid crystals are then separated from the remaining liquor by filtration or centrifugation. In analytical and synthetic chemistry work, purchased reagents of doubtful purity may be recrystallized, e.g. dissolved in a very pure solvent, then crystallized and the crystals recovered, in order to improve and/or verify their purity.

-Adsorption removes a soluble impurity from a feedstream by trapping it on the surface of a solid material such as activated carbon which forms strong noncovalent chemical bonds with the impurity. Chromatography employs adsorption and desorption on a packed bed of a solid to purify multiple components of a single feedstream.

-Smelting is used to produce metals from raw ore, and involves adding chemicals to the ore and heating it up to the melting point of the metal.

-Refining is used primarily in the petroleum industry, whereby crude oil is heated and separated into stages according to the condensation points of the various elements.

-Distillation, widely used in petroleum refining and in purification of ethanol separates volatile liquids on the basis of their boiling point.

Water purification combines a number of methods to produce potable or drinking water.

-Downstream processing refers to purification of chemicals, pharmaceuticals and food ingredients produced by fermentation or synthesized by plant and animal tissues, for example antibiotics, citric acid, vitamin E, and insulin.

-Fractionation refers to a purification strategy in which some relatively inefficient purification method is repeatedly applied to isolate the desired substance in progressively greater purity.

-Electrolysis refers to the breakdown of substances using an electric current. This removes impurities in a substance that an electric current is run through

Hope I helped. :)

Answer 2

Fill clear PET bottles with the stuff and lay them in the sunlight for six hours if sunny, or two days if cloudy.  Laying them on a dark surface could also be a good idea.  Make sure you use clean, clear plastic bottles, not grubby coloured ones.

This simple method is now being employed in at least thirty of the world's poorest countries.  Even impoverished areas tend to have lots of such bottles lying around.

Answer 3

You could use a clear plastic sheet with 2 concentric rings for each sheet.

First thread the center of the sheet through one of the rings and cut a hole

and fold the plastic back over, and,

use the second ring to hold the first ring in place.

The sheet is to be stretched far enough apart that it would appear to be a very flat funnel,

and supported high enough above ground level for you to be able to walk under comfortably.

When it rains, the water hits the funnel shape of the sheet,

and runs down the center hole between the rings.

Then you could either have a container to catch the rainwater placed beneath the hole,

or,

you could run a plastic pipe from the side of the container

at a slight angle downward to a second container

that has a small amount of calcium hydroxide lime to help settle out any solid dust particles,

or bugs or other stuff from the rainwater.

After the solid particles have settled out into the lime,

gently tilt the container and pour off the water into another container

leaving the lime and other stuff in the first container.

Then add a small amount (probably a few drops) of either chlorine bleach,

or Iodine to the water and let it stand for a while to kill any possible bacteria present.

There is also a way you could use the Sun to distill clear water from muddy water by evaporation

using a somewhat similar setup.

I hope my answer wasn't too long, and I hope it helps you out.

There is also an article by JESSICA GOLDEN called

Saving Lives With a Straw

about a product called LifeStraw, which I think is relevant.

The book Solar Energy and Building

by S. V Szokolay

also contains information on this topic.