Delving a little further into water chemistry.
We talk only in basic layman's terms and do not attempt to look into the problems of TOXIC contamination of water. You could be thinking of using water that has these problems.... An unpleasant smell. A funny (not ha ha ) taste The water is murky... or coloured. Water can smell for a number reasons. If it has a rotten egg smell, then its most likely contains hydrogen sulphide. This smell can be rectified by first removing the solids, then aerating the water. If you get a tingly feeling at the nostrils, when your nose is in a glass of your water, then it is most likely carbon dioxide, this does not smell. Some water will give a smell of chlorine or,ammonia. This usually disappears after treatment.The two should not be confused. Water can look coloured if it contains suspended solids, remove these and the water is clear. Other water colouring can be from animal, vegetable or mineral sources, some can be removed, some can be made to look like they have been removed, but really still there, others are extremely hard to remove and retain the water as a potable water. Sometimes by just changing the waters pH, you can precipitate the colour or make it disappear. If the water becomes clear and there is no precipitant then that is what has happened. A catalyst will often work. There are other methods of removing colour Heat very often will work. Using a decolouring agent such as " fullers earth" sometimes work. There are also some nasty chemicals that will make a water crystal clear, Nevertheless, the result is toxic water. What as non-professionals, we can try. Smelly water. If the water is clear, then first try aerating the water, simply by cascading. Aerating is letting the oxygen from the air make contact with the water, TASTE. Can come from various sources. A metallic taste usually is from Manganese, Zinc, and Copper. Other tastes from Calcium and magnesium as the sulphates. Aluminium salts, sometimes iron salts. If you are storing water that is acidic in a metal vessel then expect it to have a taste. Excessive lead as salts.... Gives a sweet sickly taste to water. Again, you get a sweet sickly taste from water that has dead animal material in it. (A dead possum in a rainwater tank, gives a taste like excessive saccharine has been added.) Acidic waters held in copper or lead (this includes solder) pipes or vessels becomes toxic water.
Colour and turbidity. You can remove smell arising from hydrogen sulphide. Ammonia, Chlorine. Plus carbon dioxide. Taste In natural water, there is usually a taste from acidic organic material sometimes from waters in contact with coal or sulphides. If the taste is Bland. It is from water that is highly akaline, or carrying sodium or calcium as the bicarbonate. Metallic.taste From metal salts is most common. (Common taste from a galvanised water tank)Whereas the BLAND taste is common with concrete tanks. It's worth noting that palatable water needs some taste. For example take a drink of distilled water, and you will no what I mean. Most people like a water that has a pH from 6 to 7 therefore slightly acidic. But often supplies are between 7 and 8pH.
CHAPTER 3 The treatment of Potable water
Refer to Tables. For Flocculent.. .Alum.. .Limewater... Clay slurry.
When we talk of POTABLE water we mean water fit for human consumption. You may have water that falls into this category, but you cannot use it because of the unacceptable amount of suspended solids it contains. Such water comes from: Rivers - creeks -dame - ponds - or wells-If you have such a water. First, you need to get it tested by a recognized water authority. To do this... You must first find out the volume of sample water they the authority require. You can then test the water yourself. Collect two samples... these are one litre in volume. Call them (A) and (B) this is the water taken as it is from the original source? If it is muddy and carrying debris, then first put it through a SLOW SAND FILTER However, do not treat the sample in any other way.
(B) This sample you can give some treatment to...as... first lesson Test the pH. If it is acidic? Take a one-Litre sample.... record the pH If it is acidic? Take a one-Litre sample.... record the pH Add one drop of flocculent then stir, if a floc develops allow to settle,decant the cleared water off, then check the pH of the sample again. If the pH remains the same, then you know it is not the debris in the water that is causing the acidic reading.
If no floc appears, add more of the flocculent... one drop at a time... stir between drops. Until either a floe develops, or you have added a maximum of four drops. If no floe discard the sample... If the pH remains the same discard the sample. Record your findings.
Now start with a new sample. Add to the sample one teaspoonful of clay-slurry, stir for at least one-minute, and then add one drop of flocculent. If you get a reaction, set aside to settle. If no reaction discard the sample. When settled,decant and read the pH... If it remains the same then discard... If the pH reading shows less acid then you know the acidicity is coming from the suspended solids. Record all your findings. Start a new series of checking your sample. This is with a sample as original. Add one level teaspoon of Calcium Hydroxide as LIME WATER. Stir well for
at least, one minute. Add one drop of flocculent, if a reaction set aside to settle...then test the pH... Note it will now have changed it will now read alkaline... If there was no floc forming reaction discard the sample.
Start with original water. To a sample add one level teaspoon of Alum solution, stir well and allow settling ... If no reaction discard. If the original water is alkaline then record this fact, but do the same tests as one to four. It is unlikely that nothing happens in any test. Much more likely there is a response in all tests. The most satisfactory of your test results are. You are looking for a reasonable clear water, with the least added material, for you to get the water that way. The two most desirable samples are. [Based on assuming the water cleared] 1: The water you added 1-drop of flocculent to and nothing else. 2: The water with the clay added. Plus one-drop of flocculent and nothing else.
You now carry on trying more tests that are based on the water as  or  Take a sample to this add 10% of one drop of flocculent (To make this add one drop of flocculent to nine drops of distilled water] Stir then add another drop stirring between each drop. Stir at least one minute. Continue until the moment you get a reaction. Record your findings and set aside to settle. This test tells you the minium flocculent you need to get the reaction. You now know how much of the flocculent is required to settle the solids in a litre of your water.
Don't be tempted to add too much flocculent... The less needed the better. If you found the sample that contained clay as well as the flocculent, gave a clearer water after settling, then take another Sample Add the clay as before and then proceed with the 10% solution of flocculent... drop by drop as before, Stirring between each drop until you see a reaction. Record your findings and put aside to settle. Again you now know the minium flocculent required.
Let's suppose the third original sample looked the best? If this sample is the better-looking water, then start again. Starting with an original sample.Add one level teaspoon of lime water to 9 spoonfuls of distilled water. This solution is now a 10% solution Add the amount of flocculent that was required to react with the water sample then add the 10% lime water A spoonful at a time stirring between each spoonful until you get a reaction. The least lime you add the better. When you have a reaction, record how many spoonfuls of limewater you added. Start with another sample Add the same amount of lime water as you did before, and then add drop by drop the 10% solution of flocculent until you get a reaction. Set aside to settle. This test tells you if you need more or less flocculent then the test without the lime water.
Example You got a result originally with one drop of flocculent, plus eight spoons of lime water. You found that four drops of 10% flocculent and one teaspoon of lime reacted. So your result might read To one litre sample was added. 30% of one drop of flocculent 40% of one teaspoon of lime. Resulting reaction cleared the sample of most solids. And if you are happy with such a result or one of the other, then this final cleared sample you can send away ... with the other original, to the water authority. You must always tell the tester that you added material like flocculent and lime to clear the water.
Keep in mind the limed water will be much rrtore alkaline then the other sample. If the sample you treated with ALUM was by far the best result. Then retest this water. Add alum solution to an original sample drop by drop until you see a floc forming. Record all your testing Before you send any sample away, pass it through the slow sand filter, this should be the case always..
Remember always tell the tester what was done and what you added to the water sample. NOTE
For potable water, here are the maximum amounts of chemical materials you can add to the water You are sampling. And the water remains potable. To a litre... 20% of one drop of floculent 10% of one drop of Alum.
Testing domestic wastewater.
There are no hard or fast rules, in treating Domestic wastewater ... or by its other name 'Greywater'. Each indivual needs to experiment until they get a satisfactory result. It is not impossible to turn grey water back to potable water, but it will be expensive, and require a sound knowledge of Water treatment chemistry. As with treating potable water, you need to take samples and treat them in much the same way. You will find that the following methods are sound and will give you reasonable water that you can use for many purposes.
Do not waste money or time having your grey water tested by water authorities As before all the samples are one litre preferably in clear glass jars. Dosage drops are as dropped from a normal type eyedropper. Teaspoons are an average type and the material is level. Stirring is most important and must be at east of one minute duration between each action. When one or more drops or teaspoonfuls are mentioned, then you stir For at least one minute between each drop or spoonful. 10% of a drop means just that. There are roughly 15 drops to one ml. There are roughly ten tea- spoonfuls to 50 ml.
Testing the grey water
Take a sample of the water to be tested. Add one spoon of Lime powder. (Lime is Calcium hydroxide... builders lime, not agriculture lime) Stir well then add one drop of flocculent. Stir and allow to settle. The above samples should be two x one litres jars with the same ingredients in each. Allow about 20 mins to settle, and then carefully decant the cleared water off. Pass the water thru a sand filter, and then put the water into just one jar. Check the pH. If 8pH or higher add enough Hydrochloric acid until you obtain neutral 7pH. Then add Alum drop by drop, until you see a floc forming. You may have to differ the quantities of chemicals applied. Aim for the least amount of any to get a satisfactory result. Try different tests as set out elsewhere in this manual. Stir well. Allow settling.You want to see a transparent floc about lmm in size particles. Allow 20 minutes to settle then decant.... Pass thru the second sand filter. You should have clear bright looking water. Check, the pH you want it to be neutral to slightly acidic say 6pH.
Tank requirements for setting up a wastewater treatment plant.
I suggest in the beginning you install a pilot plant. By doing this you can alter as required, then when you have a system up and running you can use the knowledge you gained to build what you require. Whatever you decide to use for the water treatment plant tanks... you need to know How much they hold in litres......DON'T GUESS. A 200. ltr drum holds more then 200.1trs. A 1000-gallon tank may, or may not hold 1000 gins. There is only one-way of knowing and that is to measure your tanks accurately, and place a permanent mark on each tank and keep a record.Records are all important.
Note To make it easy have the tanks capacities in hundreds or thousands or tens. (There is nothing worse then having a measure that reads say 43~. Litres. Much better to drop the 3~litres and place your mark at 40~litres) You need not have to be exactly accurate, a couple of litres out in a 200~litre tank makes little difference, but the same 2~litres matters a lot in a 60~litre tank. If you are using old lOOOgln tanks, then work out the capacity. You could use the rungs as a measure point. Example three rungs = X ~litres This is near enough, as long as you mark the tank and write records for future reference.
What can we use for the tanks of the treatment plant? You can use anything that holds water, and that is open at the top. However, about the smallest and least expensive tank would be from 200~litre oil drums. An ideal tank size for a 4 person family would be sufficient tanks that held combined 2000-litres (480 gins) I will use for my example oil drums, because they are cheap and easy to obtain. However, you could use galvanised water tanks new or old, cemented up: Fibreglas or plastic tanks. If you have pumps, you could use holes in the ground that are made watertight.
A plant made from oil drums will last about two yrs then will have to be replaced. The system you build will relate in size, to the amount of water you are using that is going to waste. This will vary a lot. If you live, where water is scarce then naturally, you are very careful what you use. Let us say to keep it all simple, you are going to treat your wastewater so at the end of the cycle you have 200~litres a day [or cycle] of reusable water. You will need a holding tank for untreated water, that holds about 300~litres .So this tank will be 2 x 200~litre drums) Your first treatment drum needs to hold 200~litres... plus a capacity for the sludge that is made, this sludge can be as high as 25% of the tanks volume. So you need 2 x 200~litre drums. For the second treatment tank, again you need two drums. Alternatively, you can hold the water in the first treatment tank and allow only enough thru to fill just 1 x 200 Litre drum. About 10% of the second treatment is waste or sludge.
If you started with 300~litres of untreated water, you have aprox: 65% [195~litres] of that as reusable water. So a reasonable rule of thumb would be a untreated water tank that holds your determined cycle period, which is a day, a week etc. You need the treatment tanks to hold the needed thru- put for that cycle and the treated water tank has to be large enough to hold the water until reused.
In a small 200~litre oil drum system you need. One drum to catch the water from the drains. Two drums to hold the untreated water. Two drums for the first treatment tank. Two drums for the second treatment tank. Two drums for the sand filters. Two drums to hold the treated water. Total. 11 drums. On a much smaller scale, you could get away with using just seven drums. Very often old rainwater tanks can be obtained. A bag of cement, some bird netting and time can make these once more hold water. Whatever you use the sequence of treatment remains the same.
Treating the wastewater within the plant
The grey water from the drains is first allowed to collect in a tank set below the drain. This tank should be screened against flies and have a mesh basket to catch the large debris. Make provision to be able to clean the tank out regularly. The water has to be elevated from this ground tank to the holding tanks. This is achieved by pump, or even by bucket. The holding tank can be dispensed with if this primary treatment tank is sufficiently large.
A cycle is. The primary treatment tank is loaded. From the holding tank. The reagents are added. The tank is stirred. The settlement period elapses. The tap is opened and water that has cleared is decanted off to the first slow sand filter. The water flows from the filter into the second treatment tank. When the first treatment tank is empty of cleared water, about 50% of the sludge formed is run to waste. When the last water has left the primary filter and all the treated water is now in the secondary treatment tank. Reagents are added. Then the tank is stirred, and allowed to settle. The cleared water is then decantered off into the secondary sand filter. When the last water has left the primary treatment tank, you can repeat the cycle.A full cycle will take about 2 hours, so it's possible to treat a large amount of water in a day. You should note that if the untreated water is left for more then two days, it might start to ferment and smell You must allow for this, and keep it covered up away from flies.
Making and using slow sand filters
Slow sand water filtration is a very old art It is rarely used today, because its slow and labour-intensive, but it remains one of the best methods of cleaning water. It can do what no other inexpensive filter can do as. A) Remove up to 90% of all bacteria in water. B) Remove up to 99% of solid matter from water. C) Breakdown Ammonia based salts by oxidisation.
When using a properly graded sand and filtering a reasonably clear water, you need. [This by the old and tried method.] One cubic foot of sand to pass 10 glns of water per hr. From intensive studies I have work out the following formula This will gives reasonable results. Fabricating a slow sand filter. Take a 200~Litre drum and cut it lengthways, so you retain about 75% of the diameter, leaving the small bung at one end. The large bunghole goes with the 25% discarded.... Set this drum up horizontally, with the bung end about 10mm lower. Screw a plastic fitting into the bung-hole that you can attach a plastic pipe. In the actual fitting push in a loose piece of a stainless steel pot cleaner so it protrudes into the drum.... This acts as a strainer to keep the sand in the filter.
Lay clean hard gravel about 3mm size to a depth of 40mm around and over the bung area and to about halfway along the bottom of the tank. Making sure it is deeper at the bung outlet and covers it by 20mm. Obtain clean hard sand; [the size of the sand is critical.] It must pass through a mesh of 4mm. But is saved on fly wire mesh. Fill the tank with this sand to about 50mm from the top edges. Then cover the surface to the edges with a layer of gravel about 13mm in size particle.
The water enters at the opposite end from the bung, which is the waters outlet. Pass the water from the treatment drums on to a square of sponge (foam.) Let the water penetrate evenly into the gravel. The flow rate must not exceed three- litres per minute for this size filter. After a period of use, the filter will block. It is blocked when the incoming water can be seen at the surface 75% over the surface. To clean. The filter. Carefully remove the top gravel, and scoop up the first or top sand To a depth of about 150 mm. Wash this removed sand well in clean water only, then replace. Replace the gravel after washing it.
Do not use anything to wash the sand or gravel except clean water.When the filter is not in use cover with wet bags and keep it wet at all times. This will keep the friendly bacteria alive .
Amongst other things microbes oxidise the Ammonia compounds. On hot days keep the filter shaded and keep the rain and birds off it.
Worth noting. The finer the sand, the better the filtration. But the slower the thru -put Experiment if you get poor results. You can build much bigger filters.... if you do, they want to be about 400mm to 600mm in depth and allow two cubic metres of sand, per litre of water Per minute.
Treatment plant size.
There is no minimum or maximum, but in practice tanks holding 60~litres is about the minimum. There is no maximum. Ideal sizes for a private user are tanks holding about four thousand litres (The old 1000 gin tanks). From the economical, accessible and the fact, you should make a pilot plant first, point of view I have settled on using 200~litre drums. (You need to adapt to what ever you use.)
A water treatment plant made from 200~litre drums can give you an output Of around 200 litres of treated water every 4 hr period. [A cycle] Using such drums has many disadvantages, a main one being they eventually rust away. Painting is not the answer; it has a tendency to peel off. However, you should get at least two yrs out of a set. In addition, they are ideal for a test plant. There are plastic drums available and these will last for many years.
To make a domestic wastewater recycler. First, study the drawings.(A set of drawing is a availble from the author as a pdf file for $8.00 which is down loadable} The reaction tanks (2) are both made as the sketch shows, you cut the bottom out of one, then turn it upside-down the 2" BSP bung-hole is the sludge main drain. Cut both top and bottom out of the second drum and get both welded together. You then have a long drum that holds 400~litres. You need two of these. Follow directions of the drawings. Cut two holes about 25mm x50mm diam: and from the inside stick in some clear plastic this will act as windows so you can see what is going on. I use the clear plastic welding lenses but any clear glass or plastic will do. Stick in with body filling bog, or silastic ...from the inside. Make sure you do it from the inside, as the pressure will blow it off if attached from the outside.
Just below the top of the 400~litre.Tank you also need an outlet. If stirring afterwoods, then first fill the drum with water. Then while stirring add the chemicals.....Stir for at least 5 minutes. decant the water off, after it has settled. (See sketch)
The primary filter is made from one drum, As is the secondary filter. Again, follow directions. The secondary reaction tank is made the same way as already said. The storage tank can be drums, but a larger tank type would be more suitable. If you make it from drums then connect at least three together.
When setting up you plant, you can use gravity for most of the system. By using pumps, you can of course have it all as you want.
Note... Both filters are slow sand type and are fed by gravitation.
To mix the reagents with the water
You can do it two different ways. A) A length of 50 to 60mm rigid PVC pipe is placed in the drum from the top cut a few slots in the bottom end. Attach this so it is in the centre. As the water runs into the drum by means of this pipe you feed in the chemicals you are using the same way. Do this slowly so when the drum is full it also contains all the chemicals that is required. This normally is all the mixing needed. B)
You can make a mechanical stirrer as per the sketch. Stirring as you fill or stir afterwards.
AN UNDERSTANDING OF THE pH SCALE
The letters pH stands for a scale of measurement of "POTENTIAL HYDROGEN" The scale reads 1 through to 14, with 7 as the neutral point. It is the method used to discover the acidity or alkalinity of aqueous solutions, therefore water. On the lower side of 7pH are the acidic readings expressed as the number of Hydrogen ions in the solution. On the high side of 7pH, the numbers represent the number of Hydroxyl ions in the solution, At 7pH the neutral point there are equal numbers of both ions.
The standard used universally of extremes therefore pH? Is expressed as full strength lpH = HYDROCHLORIC ACID. 14pH= SODIUM HYDROXIDE.
The scale 1 to 14 is logarithmic, where each number is ten times more then the number following. As example: An alkali that reads 8pH is ten times more alkaline then pure water. An alkali that reads 9pH is 100 times more alkaline then pure water. Going the other way. An average solution of vinegar (acetic acid diluted) is 4pH. A concentrated lemon juice (citric acid) is 2pH. The lemon juice is 100 times stronger then the vinegar. If we had a nitric acid solution that read lpH. Then it would be One hundred times more acidic then the lemon juice and One thousand times more acidic then the vinegar.
Universal Indicator solution will give you only an indication of the pH of water, this is usually sufficient for your needs. You can obtain "LITMUS" paper that tells you to 0.2 accuracy. Nevertheless, if you want to know exactly the pH you need a pH meter. I find you can get satisfactory results from using either swimming pool equipment or soil testing materials.
You are safe with water for human use that has a pH reading of Between 6pH and 8pH. Water around 6.8pH is usually the most pleasant tasting. However, there is a lot of surface alkaline water Around 7.5pH A understanding of the above information can help you to get suitable results in treating your water.
Saline or salty water? If you know or suspect the water you want to use is salty, then it is important, that you test it first. You need to know what salts are in the water. Then find out, is it economical and simple to remove them.
The most common salt, causing salinity is Sodium Chloride. It is also the hardest salt to remove. All SODIUM salts are soluble, that means no matter what you replace the CHLORIDE with, the SODIUM will remain as a compound in the water.
Note. Sodium is safest in water as the Chloride. Therefore, it is safe to assume that if the main salt in your water is a Sodium salt (potassium chemically in water is much the same) then there is little you can do, that is economical.
Not all salt in saline water is a Sodium or Potassium salt. Many of the other salts can be removed, by changing their chemical form.
Try to mesmerise the following...
All NITRATES are soluble in water, so you never add any compound that contains nitrate, nitrite, nitric materials-Many of these as compounds are poisonous. All sulphates are soluble except...Calcium Sulphate plus the nasty sulphates of Mercury, Lead and Barium. If you change CALCIUM CHLORIDE to the SULPHATE, you can remove it as Calcium Sulphate but you leave behind the Chloride, which in turn attaches itself to something else in the water. ALL CHLORIDES ARE SOLUBLE except the nasty ones of Silver, Mercury, Lead. (Meaning you cannot remove CHLORIDES easily from water)
All CARBONATES are INSOLUBLE in water Except the carbonates of SODIUM POTASSIUM. AMMONIUM. (Meaning you can remove any other mineral when it a carbonate, except The above three) AMMONIUM can be oxidised out. SODIUM and POTASSIUM you cannot remove. These two are safest as the chloride. They are nasty as the SULPHATE.
And dangerous as the Oxide.... Hydroxide and as a nitrate.
Testing salty water
If the water is dirty treat first with lime water and flocculent or Alum. Test the salt content before you start then again after filtering. If after precipitating and filtering the water, the salt content is still too high then the water contains SODIUM and or POTASSIUM. On the other hand, if you have lowered the salts content, then you know you had something soluble in the water that reacted with the reagent you added. You may get an even higher reading, this means there is now free chlorine or Nitrates in the water that have combined with the CALCIUM. And made another salt. Do not add other salts, as these will just make the water-more Saline
As example adding Magnesium sulphate to salty water, makes the water taste Less salty, but there are now more dissolved salts. The only methods of removing Sodium and Potassium salts from water are: Ion exchange Distillation-Electrodyalisis Reverse osmosis All are expensive methods.
STERILISATION of water. Simple methods. Sterilising water means removing harmful bacteria. It does not mean removing POLLUTANTS. There are numerous ways of sterilising water. A) Boiling the water. B) Biological methods. C) Filtering D) Treating with chemicals. E) Ultraviolet. Exposure. F) Ozone exposure.
Of the above methods, two are possible within a simple treatment plant. They are. C} which is Filtering. And D} using chemicals. You can combine these two methods. Try to achieve sterilisation in the simplest and most environmentally friendly way. Bacterial content of water depends much on where you obtain the water. Water from deep bores [30metres or more] is rarely contaminated with harmful bacteria. Shallow bores and wells 10m in depth, often are. Toilets, ablution blocks should never be uphill from a water supply and never close by. Water should always be suspect, unless the water is isolated from human and animals. A good indication of a surface water that is POTABLE... or nearly so. Is the variety of animal aquatic life it sustains ? If the water teems with a varied life especially FROGS and FISH, then the water is usually good. Water that contains only life as eels, yabbies, and insects are suspect (most like! polluted) Waters with no aquatic life are to be deemed as dangerous. Waters with no plant life are either saline or polluted.
If you see bubbles rising from the mud in water, then you can be sure it is polluted. REMEMBER even a good-looking [ full of fish ] water can carry dangerous bacteria. So to be safe all surface water should be sterilised. Bacteria cannot live in hostile water such as a water containing CALCIUM HYDROXIDE, therefore if you add enough, first to react with any salts in the water, and then add approximately 10% more.All the bacteria will die.This sterilisation method is referred to as the EXCESS LIME TREATMENT.
A slow sand filter will remove a certain percentage of bacteria. Bacteria perish in sunlight and when exposed to oxygen. Therefore, if you aerate water by letting it cascade so sunlight and oxygen can make contact, much of the bacteria will be removed. Using all of above within your treatment, will rid your water of bacteria.
NOTE: NONE OF THE ABOVE WILL REMOVE TOXIC POLLUTANTS.
Simple CHLORINATION as used with swimming pool maintenance is another method. It has its drawbacks. Chlorine remains in the water.
Using UltraVIOLETrays or OZONE gas methods are costly.
The metal SILVER will also kill bacteria, but is a costly method.
Here are the simplest and safest methods
1) Have all water tested for BACTERIA and POLLUTANTS. Make sure you keep your water source free of contamination- 2)Treat your water with the "EXCESS LIME METHOD" 3] Filter, then aerate. If your water carries harmful bacteria, then treat a sample. Get it tested. It is important that you take the sample, as the water authority requires. Be extra careful of re-infecting the water as you sample
REMOVAL OF IRON and MAGANESE FROM WATER.
Bore water often has these two metals in a dissolved form. They are not harmful, but can be objectionable. Both can be only held in water in a dissolved state when the pH is 6.5pH or lower, and there is little or no dissolved oxygen. They are the cause of the staining on clothes, baths and toilets.Manganese is usually in much less quantity and is harder to remove then Iron. Both minerals will precipitate out if the water is exposed to oxygen and the pH is raised to above 6.5pH. The use of a catalyst helps [a good catalyst is hession the type made from hemp or sisal. If the water as it leaves the bore is allowed to cascade over a calcium substance such as limestone or marble. Then onto the hession. A reaction takes place providing the water contains Iron. You will see a brown jelly form. This is harmless (just rust) and easily removed. As with the use of most catalysis's there is no explanation, just that it works. Make sure its real hession and the material is free of chemical residue. Another way of using hession is to cover the sand in the filter with A thick layer. So that the water has to soak through.
SOME USEFUL INFORMATION
When treating water for any purpose, work out the treatment on a small-scale first, repeat your experiments until you get the wanted result. Then double check-Always be on the mean side when adding chemicals to water, don't believe the adage "if a little works, then a lot will work better. In most cases, this is false. Always use the least amount of anything to get the wanted result. Remember many chemicals or materials once in the water, are not easily removed, it is much easier to add a little more, then to try taking out the TOO much you put in. Never put anything in water unless you understand the reaction-There is nearly always a defined order of applying treatment, don't twist it around. Flocculants are destroyed on contact with strong acids. Flocculants will not work if too much is used. Be always wary of adding anything containing SODIUM or POTASSIUM To the water as these, two will remain in your treated water. Never add anything to water that ends with Nitrate. Nitrite. Nitric. Remember Iron and Maganese can be removed. Both can only be held in water that contains little or no oxygen, and the pH is 6.5pH or lower. They are the cause of rusty staining on clothing and such staining on baths and basins Manganese is normally in much smaller quantities then Iron, which help, as it is more difficult to oxidise. It is simple to make iron precipitate, usualb just by aerating the water, therefore letting oxygen maketontact. It can help very often to add a little alkali tc raise the waters pH. The iron will then turn the water a rusty colour, filtering then removes the solid iror Manganese can at times be harder to remove; it is the cause of black staining. Manganese normally will precipitate if you try the following*. Use POTASSIUM PERMANGANATE after you have raised the pH above 7pH Because this chemical it expensive always try the above methods first. Both Iron and Manganese react best using the foresaid methods if a catalyst is also used. I have found one of the best catalysis is ordinary Hemp or Sisal hessian (make sure it is one of these organic hessions) Plastics materials are useless.
CHAPTER 11 Water Softening. Freshwater that will not lather, when you use ordinary soap is referred to as being HARD. Such water contains CALCIUM HYDROGEN CARBONATE Hardness can be of two types. TEMPORARY and PERMANENT HARDNESS. Temporary hardness is from Calciumhydrogencarbonate. This type of hardness is removed from the water, when the water is boiled, and the precipitant is the scale you see inside a kettle. Permanent hardness is from Calcium and magnesium sulphate, you can alter this chemically by substituting the Calcium and magnesium with Sodium. The Calcium and Magnesium then precipitate out. But you end up with more salt in the water (Sodium Sulphate)
Hardness is only a problem using soap, not detergents Common soap is. Sodium stearate plus Calcium sulphate the two react and the result is. Calcium stearate that is the scum on the water and Sodium sulphate that stays dissolved in the water.
You can treat "HARD" water by this method. By adding Calcium Hydroxide [buildersslaked lime] to water. Chemically you have in the water ions of calcium and hydroxyl. Hydroxyl plus the carbonic acid [ that is already in the water], turns to Carbon dioxide. This Carbon dioxide unites with (a) the calcium you added as the hydroxide (b) The calcium that was the Temporary hardness ...therefore the Calciumhydrogenoarbonate. Calcium + Carbon dioxide = Calcium Carbonate. Magnesium + Hydroxyl = Magnesium Hydroxide. Both will precipitate To remove permanent hardness you break the bond of the Calcium and Magnesium with the sulphate. By adding Sodium Carbonate. The Calcium and Magnesium as sulphates become Calcium Carbonate and Magnesium hydroxide- The salt remaining is Sodium Sulphate.
Worth noting. • In real, the following are slightly soluble in water, so some always remain in solution, Calcium Carbonate. Calcium sulphate, Magnesium Hydroxide When adding Calcium Hydroxide to hard water allow approximately 10-20 ppm more then the theoretical amount required, this will prevent so-called. After precipitation. This is when much later after you have filtered the water it goes cloudy. Meaning the Calcium has solidified. If you are sterilising the water, then the "LIME" treatment will solve the Temporary hardness problems. If you do have "after precipitation" problems (therefore milky looking water) then you can use a small amount of Sodium phosphate. "Calgon" is the trade name for a complex compound of Sodium Phosphate. This prevents solids forming and is used as a water softener.
SOME NOTES ON OTHER METHODS OF WATER TREATMENT.
There are many methods of water treatment, that are allied to Water treatment companies-Very few companies are interested in " Do¬it-Yourself' Systems. Most water engineers are in fact hostile to "amateurs' attempts at treating water. If you employ a qualified, experienced, tertiary educated water technician. Then expect to pay highly for the expertise. Few people that are "in the trade" are interested in any water treatment, that does not follow Accepted practice. Such people follow the same well-tried accepted methods; these fall into mainly the following groups: If water is saline then you have three methods to choose from...
REVERSE OSMOSIS...DISTILLATION...ION EXCHANGE. All three are expensive to use.
A)Reverse osmosis is not new, but it has become cheaper to use. The heart of the system is a semi-permeable membrane that allows pure water To pass through, but withholds salts and other substances: It has some big drawbacks. It produces DE-IONIZED water; you need to add certain minerals to make it drinkable. The higher the salts content, the more this method costs. You need a thorough understanding of chemistry in all forms to manage and maintain. There are many ongoing costs. Reverse Osmosis is most economical on water that has been thoroughly filtered and the water is only slightly brackish. It is a costly method of treating sea water. There is a lot of waste.
Distillation. In practice, you turn the water to steam, and then condense the steam back To a DE-IONIZED water-Again, you have to add minerals to make it usable. Unless you have access to cheap power, it is a costly method to operate.
Is a very clever way of demineralising water?
The idea has been around a long-time, and in the past mainly used to soften water, but by using multiple exchanges you can DE-IONIZE the water fully. Ion exchange equipment costs a lot to set up, and you need a thorough understanding of chemistry to be able To run the plant efficiently
Notes on water contaminants
Material found in water can be organic or inorganic, or a mixture of both. Organic material is the solid and dissolved matter within the water. That came from animal and vegetation sources. The colouring of the water if organic comes from both sources. Below surface waters, normally do not contain much organic material, but its possible that organic substances can and do enter from the surface. The colour, smell and taste of surface waters can originate from both organic and inorganic sources. As example,... the dark coloured water often seen is dyed with Tannin from vegetation. Foul smelling water originates from decaying organic mater and the expelling of inorganic gases as Hydrogen sulphide. Decaying algae often produces toxins. In what can be termed'wholesome' surface water, there is organic matter decaying all the time, this is balanced by the oxidisation taking place and the sunlight. Such water is referred to as being 'balanced' It is only when this balance is upset that problems arise. Surface water as well as subsurface water usually contains dissolved inorganic material. Too much of any of these minerals will cause the water to be hostile towards living organisms... such a water is referred to as 'dead' A common occurrence is to see Swamps Rivers and lakes all now dead from contamination of toxins, many of which are manmade or transported to the water by man. The contaminant often is salts. These can vary in type, but the most common are the salts of Sodium, Potassium, Calcium and Magnesium. To a lesser degree, but more insidious are the salts of heavy metals. The latter are unwanted in any concentration. Whereas the former are desirable in small quantities. The salts of Iron, Manganese, Copper, Zinc, tin, Aluminium and many other metals are found in most water... such salts can be removed with varying degrees of success.
CHAPTER 12 POTABLE AND INDUSTRIAL WATER TREATMENT
SLOW SAND FILTERS
1.GENERAL The first complete explanation of the biological process of purification Which takes place in slow sand filters was given in 1899. The principal reason for the decline in the construction of slow sand filters during the last 4 to 5 decades is that they have the following inherent disadvantages when compared with more modern methods of purification:-- (I) initial cost is usually high compared with modern rapid gravity filter plants;
(ii) Large areas of land are needed; (iii) the cleaning requires a large labour force; and (iv) they are not suitable for dealing with waters containing any appreciateable quantity of suspended matter. For these reasons, few new slow sand filters have been built during the 70 years, and those constructed have usually been extensions to existing Plant. There is no doubt, however, that from some raw waters, slow sand filters, aided when necessary, can produce water of excellent quality at a working cost which, even where labour charges are high, can be lower than that of a plant using Chemical coagulation as part of the process. different types, but finds that in some respects the water produced so far is Inferior. The high running cost of coagulation was found to offset the high capital charges on double filtration, so in total cost there appeared To be little to choose between the two methods.
(a) Basic structure Since many of the filters constructed during the latter Half of the nineteenth century and the early part of the twentieth are still in use, it is proposed first to describe their form of construction and subsequently to give brief details of a few recent improvements in design. The traditional British slow sand filter is an open basin, usually rectangular in shape, built below finished ground level and varying in area from a fraction of an acre up to one or two acres or even larger. The filter walls were either nearly vertical and built of masonry or brickwork backed with clay puddle, or of concrete usually faced with masonry Sometimes they had sides sloping at an angleof 30 to 40 dgrees. To the horizontal and paved with bricks on concrete or on clay puddle. This latter form is uneconomical in the use of ground, leads to settlement and leakage if the side slopes are on built-up ground and encourages algae growths in the shallow water on the side slopes. Early filter floors were paved with brick on clay puddle and later with Concrete. On the floor is laid the underdrain system, usually consisting of a main drain recessed into the floor with lateral drains laid on the floor, formed of open-jointed bricks or perforated tile drains spaced at intervals of 5 to 20ft. On these are laid layers of successively finer gravel to a depth of about 2 ft. And above this the bed of sand 2 or 3 ft. In thickness. The Sand is usually of a graded type with effective size about 0-3 mm. and uniformity coefficient 1-7 to 2-0 measured by the American Hazen Rules—(google this for more info)
(I) effective size = size of opening through which 10 per cent of the Sand by weight will pass; (ii) uniformity coefficient size of aperture through which 60 per cent of the sand by weight will pass, divided by size of opening through which 10 per cent of the sand by weight will pass.
It was at one time thought necessary to make special provisions to prevent water bypassing the sand down the face of the filter walls; this was done either by inserting projecting courses of masonry or brickwork, using sloping sides, or by carrying the sand down to the filter bottom round the edge of the filter and ending the underdrains a few feet short of the walls. Later, it was proved there is little tendency for this form of bypassing to occur, especially if the face of the filter walls has a slight outward. Although in many cases in Europe and in North America slow sand filters are covered as a protection against freezing and algae growths, this practice has not been adopted in Britain. It is expensive in first cost And increases the cost of cleaning and resanding.
(a) Aluminium sulphate (sulphate of alumna, alumina, alum,Aluminoferric) This coagulant is commonly known and referred to by any of the above terms, but aluminium sulphate and sulphate of alumina only are chemically correct.
"Alumina" is, strictly speaking, aluminium oxide.
"Alum" is often used to mean potash alum, one of a large family of double salts including iron alum, chrome alum and ammonium alum.
"Aluminoferric" is the trade name for a particular brand of aluminium sulphate widely used in paper mills, and for treating water and sewage. Aluminium sulphate as used in water treatment is not a pure chemical but contains varying amounts of water of crystallization and so the percentage of alumina or aluminium oxide (Al,0,) varies according to the purity and the physical character of the chemical. When added to water, the main reaction of aluminium sulphate is with either the natural alkalinity, such as calcium bicarbonate, or with added alkalinity in the form of lime, soda ash or, less commonly, caustic soda, resulting in forming a colloidal aluminium hydroxide which then thickens into large particles like snowflakes in which suspended matter and colour in the water are mechanically trapped or adsorbed.
The reaction of the added aluminium sulphate with the water results in a lowering of the pH value, unless alkali equivalent to the acidity produced by the aluminium sulphate dose is also used. Waters so treated have their pH value lowered to a greater degree than if lime or some other alkali were used. The use of one or other of these alkalis depends on the nature of the water. Soft, coloured and acid waters present many problems in coagulation and are difficult to clarify satisfactorily as the doses of both coagulant and alkali are critical; to preserve a high-quality filtrate careful control is necessary In order of importance the dose of coagulant must be adjusted for pH value, colour and turbidity. These waters coagulate best in the pH range of 4-5 to 6.5, as in this range maximum colour removal is obtained with producing a quick settling floc and the minimum residual aluminium in solution
Waters of the second group, containing medium amounts of natural alkalinity, react readily with aluminium sulphate within the pH range 6.0 to 7.2. Waters of the third group, sometimes containing natural sodium bicarbonate also, are difficult and require large doses of aluminium sulphate and sometimes also a dose of
sulphuric acid, chiefly for reducing the pH value to a figure within the range for effective coagulation, Which in temperate zones is from 6.0 to7-2. Occasionally coagulants other than aluminium salts are used success¬fully for soft acid or for alkaline waters and further reference to these will be made later,
(b) Sodium aluminates In contrast to aluminium sulphate, sodium aluminates is a white alkaline powder freely soluble in water to give an alkaline solution. When used in treating waters for the removal of suspended matter and decolourisation, it is to be regarded as an auxiliary coagulant as it is nearly always used in conjunction with aluminium sulphate. The dose of sodium aluminate may vary from 0-7 to 40 ppm- but in practice the ideal dose will be from one-twentieth to one-tenth of the aluminium sulphate dose. In practice it has been found the best results are obtained when sodium aluminate is added a short while (1 to 2 minutes) before the aluminium sulphate. On no-account should the two reagents be mixed before addition to the water. When it is found possible to get good results from the use of "alum" and sodium aluminate (referred to as double coagulation), it will give some or all the following advantages:- (I) effective coagulation over a wider range of pH values with consequent simplified control; (ii) a greater degree of clarification and decolourisation; (iii) a denser and tougher floc is often produced which settles more rapidly, giving longer filter runs and a saving in wash-water.
Occasionally it is found, with soft moorland waters, that to gain satisfactory results aluminium sulphate must be added in such quantity that the pH value is lowered to between 6-0 and 5-0 but at such low pH value the water contains more residual alumina than is considered desirable. In these circumstances small doses of sodium aluminate can be employed with advantage to produce a filtrate having a low residual alumina content, which is thus safe from after-precipitation.
It is often found that iron salts can be used in place of the more expensive aluminium salts producing a heavier and denser floe over a wider pH range, Both above and below that usually found best for aluminium sulphate. On the other hand many iron salts require the use of lime or other alkali to give complete precipitation and some are very corrosive, needing more expensive solution tanks and dosage equipment; finally, to prevent iron remaining in solution, a fair degree of skilled and close control of treatment is needed. Ferrous sulphate (Copperas, iron sulphate or sugar of iron).~Ferrous sulphate is the cheapest of all salts that can be used for coagulation. The commercial variety can be bought in small broken lumps or in a purer condition as light green crystals, similar in size to granulated sugar. The chemical formula is FeS0,.7H,O, the material containing 29 per cent of iron oxide as Fe,O,.
Ferrous sulphate is not recommended for soft, coloured waters; but it is suitable for all saline bicarbonate waters or neutral surface waters containing some bicarbonate. Ferrous sulphate alone is never employed in clarifying domestic supplies but is more widely used in the lime or lime and soda precipitation softening of water and in treatment of industrial wastes. If ferrous sulphate is not used in the form of chlorinated copperas, it is necessary to ensure the water being treated contains enough dissolved oxygen for oxidation of ferrous sulphate the iron, and the pH value is raised above 8-3 by alkali, preferably lime or caustic soda.
Used in conjunction with chlorine, ferrous sulphate becomes converted into a mixture of ferric chloride and ferric sulphate when the ratio of chlorine to ferrous sulphate is not less than 1 part of chlorine to 78 parts of ferrous sulphate.
Although certain difficulties in preparation and feeding occur, chlorinated copperas is an effective coagulant with many applications. It is now used both in softening and clarification plants for drinking supplies. It is effective over a wide range of pH values, is active at low water temperatures, offers the opportunity of combining prechlorination with coagulation and it can be employed for the removal of manganese, copperas as a coagulant. This is usually prepared by making up a 10-15 per cent solution of copperas, and treating it with gaseous chlorine, either by bubbling the gas through it, or, alternatively, by passing the iron solution through an injector, allowing a measured volume of chlorine gas to be drawn in with the solution. It is essential to ensure that the ferrous iron is completely oxidized by the chlorine to the ferric state, and it is found that approximately 7 parts of ferrous sulphate require 1 part of chlorine Ferric chloride.~The corrosive nature of this salt, combined with considerable storage and feeding hazards, has prevented any large-scale application. It is marketed in anhydrous, crystalline or liquid form.
(iii) Ferric sulphate.—Marketed as small light yellowish-green granules containing 89 per cent Fe,(SO,), this reagent, while it offers many advantages-ages over ferric chloride, has found little favour in waterworks practice, owing to its cost and the difficulty of supply in many countries. (iv) Activated or modified silica This coagulant aid which consists of a dilute solution (0-7 to 1-0 per cent SiO,) of a partially neutralized and aged sodium silicate has found increased use and experience has proved that once the technique of preparation has been mastered few difficulties are encountered. The strongly alkaline commercial sodium silicate is partially neutralized by one of the following reagents: hydrochloric or sulphuric acid, sodium bicarbonate, carbon dioxide, aluminium sulphate or chlorine; and after standing (ageing) for 1 to 2 hours or less, according to the strength of the activating agent, it is then immediately diluted so the silica content of the solution is between 0-7 and 1 per cent, in which state the activated or changed silica is added to the water being treated. Activated silica is used with the main coagulant, being added just before or just after it. There are other flocculants. on the market, the best types are synthetic These are available under various trade names from water treatment suppliers. You will notice as you treat water that many common materials act as floc formers. These include Salts, Acids and Alkali.
Cationic coagulants are organometallic polymers used alone, or in blended form to replace ferric sulfate, ferric chloride, aluminum sulfate, aluminum chloride, calcium oxide (lime), calcium chloride and magnesium oxide. Because these coagulants contribute essentially no dissolved solids, and very small amounts of precipitated solids, the volume of sludge generated is greatly reduced, which in turn reduces the cost of sludge removal.
GREEN WATER! The problems associated with Algae This chapter the author did not write – added to assist the reader to understand water.- author unknown
First of all, what is it? Green water is caused by an excessively large number of tiny organisms in the water. Called phytoplankton, these minute plants are part of the algae family that has thousands of distinct species found in water (and ice) throughout the world. These organisms are very small, with the most common ones found in our ponds being around 15 microns (0.0006 inches) in diameter. All pond water contains large numbers of different kinds of these plants and other microorganisms. Water that appears to be crystal clear just doesn't have as many. Although there are many different species of organisms in any pond, I have found that there are a very limited number of species that predominate. You probably don't care what their actual names are, and I can't pronounce them, let alone spell them. For now, we will just lump the most predominant into two categories of interest and ignore the rest. The first category contains the single (or few) celled plants responsible for the algae blooms, which I will refer to as bloom algae. The second category will be called string algae, and consists of the multi-celled, filamentous plants that grow on the walls of the pond (and thrive on the waterfalls). A limited number of pond water samples from outside the local area were observed to contain basically the same mix of predominant species, but there may be different dominant species in other localities. There are three ways of controlling unwanted plants, i.e. weeds, just as in your garden. They can be: starved of the necessities for life to prevent them from multiplying; removed; or outright killed. Our problem is to find a way to do one or more of these without harming our aquatic life that are sharing this environment. Let's review the common myths and check out the facts. Perhaps the most controversial myths involve starving the algae of the necessities of life. Algae have specific requirements for growth just as any other plant. If we can remove or reduce one or more of the required items, algae cannot flourish. Unfortunately, each species of algae has slightly different nutrient and environmental requirements. Besides the primaries of sunlight, suitable temperature, pH, and salinity ranges, all are known to need elemental Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Iron, Calcium, Magnesium, Copper, Manganese, Zinc, and Molybdenum. In most cases, each of these elements are required to be in an inorganic form. Many of these are also requirements of the other life so we can't mess around with them very much. Some of the required elements have minimum concentration values that are very small. Even if we were successful in removing a critical element, a light rainstorm or even a windy day can add more than is necessary back into the water.. Often, an attempt to control one element will change the concentrations sufficiently to cause a different species of algae to thrive. Here are two widely believed myths . MYTH: Pond algae blooms are primarily related to various nutrient concentrations in the water. FACT: There is no evidence to substantiate any relationship between nutrient levels and the inception or termination of the common algae blooms in most water. Quite to the contrary, the measurable nutrient levels are normally so high, most questions should be why the algae bloom is not continuous. Further, most of these nutrient concentration levels actually show a slight increase after a heavy bloom subsides. This myth arises from invalid extrapolations and application of true scientific findings based on studies of large lakes and oceans. An excellent case can be made for a relationship between algae blooms and nutrient levels within the open areas of large bodies of water. Lakes and oceans become stratified with various areas having different nutrient, oxygen, and temperature levels, hence varying population conditions. Most of these scientific findings just simply do not apply to the essentially closed environment of an established pond or dam.
MYTH: Providing shade over the pond will prevent an algae bloom. FACT: It is true that algae needs light to grow and reproduce. But what is interesting is the small amount of light that is actually required. Controlled experiments using reduction in sun light of 90% still show significant algae growth. I can cite many examples of ponds that are heavily shaded but quite green and just as many others with direct sun exposure that have no algae bloom problems at all. There are also several examples of ponds located inside buildings that receive almost no sun light, yet are pea soup green. There have been positive results reported of completely covering a pond suffering from green water with an opaque plastic cover for 5-10 days. I'm not too sure what the other aquatic life think about this but it is obviously not an acceptable permanent solution. I do recommend providing shade over a pond, but more for temperature stability than for algae control. Now let's look at the myths involved with removal of these weeds.
MYTH: A mechanical filter system will remove bloom algae from the pond water. FACT: It is impractical to remove these weeds by mechanical means. As we saw above, they are so tiny that they will pass through any feasible mechanical filtration device as if it wasn't even there. If the filter was fine enough to capture the bloom algae, it would plug up in minutes with the other, much larger, particulate matter in the water.
MYTH: A flocculent treatment of the pond water will clump the algae together into large enough sizes that the filter will remove them. FACT: Flocculents only have a very weak effect on the living algae cells but can be effective in causing some organic waste and inorganic particles to clump. Further, most flocculents are alum based whose principal component is aluminum. There are no known studies of the long term effects of aluminum on fish.
MYTH: A major water change out will clear the bloom algae. FACT: Although a major water change out will temporarily remove a portion of the bloom algae, it will actually make the situation worse and the algae bloom will normally increase shortly after the water change. Now we are left with the killing solution to look at. We obviously could pour a large amount of chlorine or arsenic into our pond and either would do an excellent job of killing the algae but there would also be a similar undesirable effect on the fish and other desired water inhabitants. There are many so-called algicides on the market. Most of those available are copper based. Although those containing chelated copper may be less toxic to fish, it has been shown that the long-term effect of copper build-up in fish is a problem. Dosages are critical. Too much will kill the fish; too little will not do anything (except maybe long term side effects to the fish and frogs).
I cannot overemphasize: BE EXTREMELY CAREFUL OF ANYTHING YOU PUT INTO YOUR Water!
MYTH: Addition of salt to the water will kill the bloom algae. FACT: The predominant species of algae in our water are only slightly affected by salinity levels that can be tolerated by most fish. Some species of algae cannot tolerate more than about 1 ppt (part per thousand) of salt in the water while others cannot survive if the salinity is less than 1 ppt. Neither of these particular species normally contributes to an algae bloom. Nothing says WE have to kill the bloom algae; how about having another creature act as a hit man for us?
MYTH: The nitrification bacteria in the biologic filter kill and eat the bloom algae. FACT: The nitrification bacteria are chemolithotrophs which means they use only inorganic chemicals as their energy source. In addition to their basic requirements of oxygen, carbon dioxide, and a few trace minerals, they are very restricted to diets of only ammonia and nitrite respectively. There is another group of bacteria in the filter that one hears very little about, These are the heterotroph (chemoorganotroph) bacteria which consume dead organic matter. Technically, these organisms conduct a process called aerobic bacterial decomposition but it is more commonly known as decaying or rotting. This is essentially the same thing that takes place in a compost heap . It is easy to tell if this process is the desired aerobic (oxygen present) or anaerobic. Aerobic conditions do not produce that strong, characteristic odor. These heterotroph bacteria cannot consume any live material, only the remains. We will discuss more about them later. We now know what makes up an algae bloom and we know it often goes away, but why does it start and why does it end? Here are experiments that are simple enough that they can probably be repeated by almost anyone. Each involves a clear glass jar filled with various water samples. Added to the samples were two drops of liquid nutrients (house plant fertilizer), and a measured amount of "starter" containing both bloom algae and other organisms taken from the water suffering the green water malady. The jars are placed in a sunny kitchen window,and stirred at least twice daily,the bloom algae growth rates are determined using a biological microscope at 140x. No temperature controls were maintained. In the first set of tests, samples consists of distilled water, dechlorinated tap water, and local ground water. All are aerated and nutrients and starter are added to each. Bloom algae growth rate in all samples, is checked each day. A second set of tests is made with the water samples taken from clear, established ponds and dams. The first of these samples is filtered through a coffee filter to remove most particulate matter but not any of the microorganisms. A second sample is then additionally passed through a micron filter to remove any microorganisms larger than 2 microns. Identical quantities of nutrients and starter as in the first test set are added to both samples. Most of the starter bloom algae added to these samples may die within just a few hours and end up as sediment on the bottom of the containers. This was a startling observation. Rapid bloom algae growth was observed in all of the first test samples. Not only was no growth observed in the second test samples of established pond water, but the starter bloom algae died rapidly. The only conclusion that can be reached is that: THERE IS SOME COMPONENT IN CLEAR ESTABLISHED POND WATER THAT IS TOXIC TO THE BLOOM ALGAE A third set of tests was conducted using the same procedures as the second test set except the filtered pond water samples were diluted with varying amounts of aerated distilled water. The result of a 1 part distilled water to 1 part pond water dilution was the same as for the second test set, i.e. the starter bloom algae died quickly. At 2:1, the starter bloom algae did not immediately die but no significant growth was observed. At 3:1, some growth was observed but at slower rates than the first test samples. At 4:1, rapid bloom algae growth was observed, essentially the same as in the first test set. These results suggest that whatever this toxic substance is, when it is diluted down by about 75%, it is no longer an effective inhibitor.
THEORY: Based on these semi-controlled experiments, other experiments and observations, and from researched literature, this is what I think is actually happening : When algae dies and is subjected to aerobic bacterial decomposition by heterotroph bacteria, a by-product of this process is a substance, released into the water, that is toxic to the living algae. This theory is exactly the opposite of competition effects. Remember the myths which involve the removal or reduction of some factor, such as nutrients, or light, required by the bloom algae. This theory states that something is naturally ADDED to the water that kills the bloom algae. A similar example of this effect is penicillin, a substance that is released by one microorganism (a form of yeast), which is toxic to other microorganisms. The term for a substance released by one microorganism that is inhibitory to another microorganism is called an antibiotic and that name applies here as well.
Water is more than Hydrogen and Oxygen.
Rain contains all kinds of dissolved gases such as nitrogen, oxygen and carbon dioxide from the air. In industrial areas, sulphur dioxide and nitrous oxide vapours are added to the water to form undesirable acids. As soon as this rain with a low pH penetrates the ground, a large variety of minerals and artificial contaminants are dissolved in to the water. If water dissolves through calcium carbonate the pH increases, but through organic acids it decreases again. As the water seeps deeper into the ground, most undissolved substances are removed and clear water remains, this water contains almost no oxygen. Besides dissolved minerals, iron and manganese are the main components in the water, furthermore it contains ammonium, nitrate and nitrite which are only allowed to be present in drinking water in small concentrations. Finally this water contains organic substances, which are remainders of organic sources such as plants and animals.
Water Softeners -
The Problem of Hard Water Hardness of water is measured as the concentration of the dissolved mineral salts of calcium and magnesium and can be further categorised as temporary (carbonate hardness) and permanent (non-carbonate hardness). When water containing these hardness salts is heated, the salts become less soluble, and precipitate (unlike many other dissolved minerals which actually become more soluble as water is heated). The precipitated hardness results in troublesome deposits, which may cause many problems. The inconvenience and problems caused by calcium are well known, and are evident in all aspects of daily life (industry, commerce, hotels, home etc.). For example, in steam and hot water boilers, in cooling towers and humidification systems, water heaters, dishwashers and glass washers, coffee and espresso machines in mixer taps, faucets, pumps, thermostatic valves etc. showerheads, bathroom surfaces, basin: toilets The presence of hardness interferes with the efficiency of most washing processes, such as for textiles and glassware, where the fins rinsed quality is critical. Also, hard water can lead to scale formation, which can be undesirable and costly in many manufacturing processes. The results of softening water The most effective method of water softening (removing the hardness salts calcium and magnesium) is by the process ion exchange - ions are electrically charged species of the minerals dissolved in water. The water is passed through a synthetic resin, which absorbs the calcium and magnesium ions by exchanging them for sodium ions. When the resin is exhausted,: needs to be regenerated. The resin is recharged with sodium ions by rinsing with a brine solution (sodium chloride). The hardness ions previously removed are flushed to drain during the regeneration process. Recommended Residual Hardness levels An efficient water softener will completely soften the water by removing almost all detectable calcium and magnesium. Many applications require water of this quality, but there are others, which require a specific residual hardness. Recommended hardness levels for various applications are as follows: Domestic use 4 to 5 °dH Coffee machines 5 to 7 °dH Espresso machines 0 °dH Dishwashers 0 to 2 °dH Boilers 4 °dH Steam boilers and generators 0 °dH Cooling systems depends on system Humidification depends on system.
CHAPTER 16 Iron and Manganese Removal from Well Water
Removing iron and manganese from well water is not always easy. Thorough knowledge of the water and the reactions, which can occur are required to guarantee agood results.
Iron is present in well water as a Fe2+ ion. As such it cannot be filtered. By adding oxygen to the water Fe2+ is formed, which attracts six water molecules forming Fe(H2O)63+. Fe(H2O)3 molecule is not soluble and precipitation occurs. On the surface of the filter material, mostly gravel and refined river sand, precipitation of this molecule occurs. Once this precipitation has started, an acceleration of the iron removal process takes place. Therefore, an iron removal system requires a certain initiation period, before satisfactory results are achieved. When the filter material is saturated, backwashing is required to remove the accumulated Fe(OH3). It is inevitable that some active precipitation layers are removed during this process. Therefore after every backwash, a short initiation period is required again. To guarantee a successful de-ironing of the water,
The manganese removal process works identically to the iron removal process, except that it takes place at significantly higher pH values.
Rember hession is a good cataylist for removal of both iron and manganese.35