About GREEN BATHTUB -- The Journey -- Acid Rain -- Water
Copper -- pH -- Conclusions -- Feed Back

Water...

Water acts as a solvent. Groundwater dissolves caverns out of limestone which is not soluble in pure water. Rainfall contains some carbon dioxide absorbed from the atmosphere first and later while seeping through roots and humus layers. As a result it becomes dilute carbonic acid and chemically reacts with the limestone (calcium carbonate) which converts insoluble calcium carbonate into calcium bicarbonate - quite soluble in water. The mild acid eats away limestone and forms caverns. Water drips from the ceiling to form stalictites and stalagmites form on the floor. They also depend on the calcium carbonate/calcium bicarbonate reaction. Bicarbonate evaporates and releases carbon dioxide and the residue reverts to the carbonate (limestone). Drops on ceiling are rich solutions of calcium bicarbonate. When they evaporate they leave limestone. When a drop falls to the floor and evaporates it leaves limestone there.

Notes from a radio interview with John Archer about his book "The Water We Drink"

.TOWN WATER:To make it safe, town water is treated with aluminum and chlorine to make it safe to drink. We therefore drink the dead bodies of the pathogens as well as the chemicals.
Never boil town water as it only concentrates the minerals and chlorine.

 TANK WATER:Tank water should be filtered as Health Department surveys show high levels of bacteria, some are very strong. A solid ceramic candle filter is recommended (1 micron) not carbon granules. Reverse osmosis filters are also used, but multivitamin tablets should be taken as this filter removes all salts and minerals from the water.

Notes from an advertisement for concrete tanks:-
What size tank do I need? ... Most people would agree that 5000 gallons is a minimum requirement for household use. Most families find 2 x 5000 gallons completely adequate. (Although they say if you have teenagers you never have enough water.)
How much water will I get off my roof? ... There's a simple formula for working this one out: One square of roof area + one inch of rain = approx. 52 gallons of water. Clean roof and gutters means less water lost.
Does the water stored in a concrete tank have a taste? ... Some concrete tanks can have residue remaining in the tank after manufacture. With #~##~# tanks the concrete is so dense (40MPA) and the wall so smooth that no residue remains after the curing process. Other tanks can increase the heat of your stored water, a perfect breeding ground for bacteria.
Distilled (or pure) water bonds with other substances on its way through the body and therefore robs it of minerals, ie. calcium, magnesium, etc. Water passes (diffusion) into and out of impermeable cells by electrical attraction because of the pH+ and pH-. Minerals and food are kept inside the cells and water moves in to change the pH. Trees can lift water high to their top branches by osmosis.
(Pure water can withstand 500psi in a slender tube)		 Water stored deep underground (the original water from the earth's formation) is unusable because of the dissolved salts from long close contact with the rocks (minerals).


It takes 70 gallons of water to refine 1 gallon of fuel for a car, which took 30,000 gallons of water to produce (steel, etc.)

FARM DAMS -- How to improve water quality.
Warning: This WaterNote is published as a general guide in the treatment of dam water. The chemical dosages recommended are averages only, and may not be suited to a particular water supply. If the water is intended for human or animal consumption, have a sample tested, and seek advice on the interpretation of the results. From: WATERNOTES compiled by DPI.Queensland & Waterwise Qld.
The problem of poor quality water most commonly encountered in farm dams are:
-- Turbidity (mud in suspension) -- Chemical and bacterial contamination -- Organic staining -- Reduced oxygen.
TURBIDITY: Turbidity is caused by very fine particles of clay that remain in suspension in water. This makes the water undesirable as a domestic and stock water supply. It is a separate problem to heavier sand and soil particles, which will settle out in the dam or can be filtered out after pumping.
TREATING THE SOURCE:
  • Keep the catchment area well grassed. This will reduce erosion and in turn, the turbidity of runoff to the dam. If it isn't possible to grass the whole catchment, a well grassed entry to the dam will help.
  • Use contour banks in the catchment. They will assist in reducing erosion and consequently turbidity.
  • Keep stock out of the dam and surrounding areas.
TREATING THE STORED WATER: Water is treated with coagulants which capture and react with fine clay particles causing them to settle out. Alun (hydrated alimuninum sulphate), potash alum and filter alum have been used successfully. There are also proprietary products available which have been formulated to settle out turbid water.
When using alum, the pH of the water should be between 6.0 and 7.5. If pH is less than 6.5, it should be adjusted using hydrated lime as described later. Treat the water in tanks rather than in the dam itself. Large quantities of chemicals are required to treat the whole dam at once. Also dams have a relatively uncontrolled environment compared to enclosed storage tanks, and any runoff into the dam or windy weather following treatment will reduce the effectiveness of the treatment.
TREATMENT TECHNIQUES: Three options are considered below;-
IN TANKS:- Tanks should have two outlets, one near the base to drain off the sludge deposited on the bottom, and a higher one to take off the clear water. Preferably the treatment tank should be concrete or be lined with cement or some other non-corrosive surface. The table below gives an indication of amounts of filter alum required per 1,000 litres of water.
Example: For moderately turbid water in a 4500 litre tank, the amount of filter alum required is:-- (4,500 x 40) /1,000 = 180 grams (Note: 1000 gallons - 4546 litres.)
(The above table is a guide only. The correct dosage can also be found by trial and error, by treating a small sample of water.)
Very turbid water = 100 grams -- Moderately turbid water = 40 grams
Lime will be necessary to counteract any acidity caused by the alum. Lime should be added 4 - 6 hours after the alum, and at one third of the dosage rate of the alum. More lime may be required if the water was originally acidic, and less if the water was originally alkaline. The pH can be tested using a standard swimming pool test kit. Acidic water has a pH less than7.0. The final pH of the water should be between 6.5 and 8.5.
IN DAMS:- The volume of a dam is more difficult to determine. A rough guide is to multiply the surface area (in square metres) by 1/3 of the maximum depth (in metres) by 1,000, giving the volume in litres. Quantities of alum to apply can then be calculated. Note as stated before, it is not recommended to treat the dam directly.
CLARIFIERS:- There are commercial clarifiers available which cater for household or small community use. They are fully automatic with chemical feed pumps and sludge removal, but are fairly expensive and only cater for low flow rates. They are usually simple to operate. However, a clarifier cannot be bought "off the shelf". It must be matched by the manufacturer to the quality of the water supply.
Effect of alum treatment: Alum treatment causes settlement of suspended matter only. It will not reduce any chemical or bacteriological comtamination of the water.
CHEMICAL AND BACTERIAL CONTAMINATION. Treating the source:
-- Minimising the presence of stock and chemcials and maintaining a clean catchment will reduce contamination. Contour banks, by reducing the severity of the runoff, may reduce the amount of chemicals in the run off.
Bacterial control:
-- The water should be clear and have a pH of about 7.0. Chemicals required to adjust the pH should be used strictly in accordance with the supplier's recommendations particularly in regard to personal safety.
-- Chlorinate using either sodium hypochlorite (liquid), or calcium hypochlorite (powder).
-- As a first trial, add 35ml of sodium hypochlorite or 1gram of calcium hypochlorite for each 1,000 litres of water to be treated.
-- Test with a swimming pool test kit. Increase or decrease the concentration as necessary.
-- Allow 30 minutes to 1 hour before use.

Following treatment, the free residual choloine level in the water at the point of use should not be less than 0.2 milligrams per litre and not more than 0.8 milligrams per litre. Aim for 0.5 milligrams per litre. These chlorine producing chemicals should be applied in a tank (preferably clean and roofed) and not the dam. This will prevent unnecessary wastage as the dam would require a large quantity of chemicals. Also chlorine is quickly dissipated when exposed to sunlight.
Non-bacterial contamination.
-- Chemicals such as dissolved salts and pesticides can exist in water at harmful concentrations. These can be tested for in a laboratory - refer to WaterNote 'Sampling Your Water Supply".
ORGANIC STAINING: Coloured water may cause staining of domestic utensils and clothes.
Control: Alum will remove any suspended matter and chlorination will make the water biologically clean, both of which will assist in reducing the discoloration of the water. But it may not be possible to clear the water completely.
LOW OXYGEN LEVELS IN DAM. In summer the surface layer in the dam will become hotter and therefore lighter than the cooler, denser water underneath. This tends to prevent oxygen reaching the deeper water. Suitable shade trees around the edge of the dam will help control this problem.

"GREEN BATHTUB" was built in April 2002 by K van Riel*- estaria13@yahoo.com.au
Content supplied by C van Riel- greenbathtub@yahoo.com.au
LAST UPDATED-2.5.02