Water Purification Equipment
Water Purification Equipment
Water Purification Equipment
Water Purification Equipment
 

Water Treatment

TDS = Total dissolved solids Ppm = Parts per million

Drinking water SABS standards

1 2 3 4 5 6
Determinants Units Upper limit ranges Class 2 water, consumption period, max
Class 0 (ideal) Class 1 (acceptable)

Class 2 (max.allowable)

Physical and organoleptic requirements   Good water Semi water Bad water Maximum consumption of bad water
Colour mg/l < 15 15-20 >20 - 50 No limit
Conductivity at 25 mS/m < 70 70-150 >150-370 7 years
Dissolved solids mg/l < 450 450-1000 >1000-2400 7 years
Odour TON <1 1-5 >5-10 No limit
pH value at 25 pH units 6,0-9,0 5,0-9,5 4,0-10,0 No health effect
Taste FTN < 1 1-5 >5-10 No limit
Turbidity NTU < 0,1 0,1-1 >1-10 No limit
Chemical requirments-macro-determinants
Amonia as N mg/l < 0,2 0,2-1,0 >1,0-2,0 No limit
Calcium as CA mg/l < 80 80-150 >150-300 7 years
Chloride as Cl mg/l <100 100-200 >200-600 7 years
Flouride as F mg/l <0,7 0,7-1,5 >1,0-1,5 1 years
Magnesium as Mg mg/l <30 30-70 >70-100 7 years
(Nitrate and Nitrite) as N mg/l <6,0 6,0-10,0 >10,0 - 20,0 7 years
Potassium as K mg/l <25 25-50 >50-100 7 years
Sodium as Na mg/l <100 100-200 >200-400 7 years
Sulphate as so mg/l <200 200-400 >400-600 7 years
Zinc as Zn mg/l <3,0 3,0-5,0 >5,0-10,0 1 years
Chemical requirments-micro-determinants
Aluminium as Al µg/l <150 150-300 >300-500 1 years
Antimony as Sb µg/l <5 5-10 >10-50 1 years
Arsenic as As µg/l <10 10-50 >50-200 3 months
Cadium as Cd µg/l <3 3-5 >5-10 6 months
Chromium as Cr µg/l <50 50-100 >100-500 3 months
Cobalt as Co µg/l <250 250-500 >500-1000 1 years
Copper as Cu µg/l <500 500-100 >1000-2000 1 years
Cyanide (free) as CN µg/l <30 30-50 >50-70 1 week
Cynaide (recoverable) µg/l <70 70-200 >200-300 1 week
Iron as Fe µg/l <10 10-200 >200-2000 7 years
Lead asPb µg/l <10 10-50 >50-100 3 months
Manganese as Mn µg/l <50 50-100 >100-1000 7 years
Mercury as Hg µg/l <1 1-2 >2-5 3 months
Nickel as Ni µg/l <50 50-150 >150-350 1 years
Selenium as Se µg/l <10 10-20 >20-50 1 years
Vanadium asV µg/l <100 100-200 >200-500 1 years
Chemical Requirements-organic determinates
Dissolved organic carbon C mg/l <5 5-10 >10-20 3 months
Total trihalomethanes µg/l <100 100-200 >200-300 10 years
Phenols µg/l <5 5-10 >10-70 No limit
The limits for consumption of class 2 water are based on tne consumption of 2 litres of water per day by person of mass 70 kg over a period of 70 years. The limits given are based on aesthetic aspects. No primary health effect - low pH values can result instructural problems in the distribution system. These values can indicate process efficiency and risks associated with pathogens. When dissolved organic carbon is deemmed of natural orgin, the consumption period can be extended. This is a suggested value because trihalomethanes have not been proven to have any effect on human health.

Microbiological requirements

1 2 3 4 5
Determinants Units Allowable compliance contribution
95 % of samples, min. 4% of samples, max. 1% of samples, max.
Upper limits
Hetrotrophic plate count count/ml 100 1000 10 000
Total coliform bacteria count/100ml Not detected 10 100
Faecal coliform bacteria count/100ml Not detected 1 10
E.coli count/100ml Not detected Not detected 1
Somatic coliphages count/10ml Not detected 1 10
Entric viruses count/100ml Not detected 1 10

Protozoan parasites (Giardia/Cryptosporidium)

count/10ml Not detected Not detected 1
The allowable compliance contribution shall be at least 95 % to the limits in column 3, with a maximum of 4 % and 1 %, respectively, to the limits indicated in colum 4 and column 5. The objective of disinfection should, nevertheless, be to obtain 100 % compliance to the limits indicated in coloumn3. In most instances it will not be necessary to conduct these tests; one or the other will normally suffice as required indicator

 

MAGANESE DIOXIDE

For the removal of Iron magneseium and other heavy metals.

Also known as Greensand and Exfetron. If you have red muddy river or borehole. Generally the red is from all the iron oxide in the water. Or if you get red stains in your washing. When chlorine is added to water it causes the iron to preciptate into a red sludge whIch blocks pipes and leaves stains on your laundry. Certain washing powders contain bleach (chlorine). Your water may appear clear but after adding bleach or chlorine it will turn red. The chlorine causes the iron to precipitate out of solution so you can see it. To remove iron and maganese in basic terms magnese dioxide is like a big magnet that draws iron and magnesium and heavy metals out of the water. A filter vessel with a minimum bed depth of 800mm must be used for maximum water contact with media. Once the the media is fully saturated with the iron oxide it can be backwashed and cleaned. maganese dioxide (Green sand) has a undetermined lifespan . Semi automatic and manual vessels are available for this a minimum of 2 bar pressure is required

POLYPHOSPHATE

This product has many different names but they all do the same thing. This product comes in opaque crystal form which can be round balls or jagged stones salty by taste. Phospates can be found in milk. This product is genrally used as a cheaper way to fix high calcium content in water. This product will not work efficiently after a TDS of 500ppm. Calcium particals have a jagged edges which stick to the walls of pipes elements and geysers. Calcium build up is worse when heat is applied (white scales). Posphates coat calcium particles to make them smooth so they cant stick to pipes geysers and elemets anymore. IMPORTANT phosphates do not remove calcium from the water it just stops calcium from becoming a problem. After prolonged use this product well even begin to descale exsisting pipes. About 1.5 kgs will last a coffee shop about six months. The crystals will slowly desolve and the phospate will have to be topped up. phosphate replacement will also depend on how much water is used and flow rate of water. To remove calcium from water, a water softner will have to be used which is a more expsensive option.

WATER SOFTNERS (WATER CONDITIONER)

Contain Resin beads that absorb (remove) calcium and magnesium. These two elements are the main elements that constitute hard water, depending on the quantiy of these elements in water determines how hard the water is. Once they have been removed, you now have soft water. Hardness is basicaly the measurment of water to thick fluid transistion. The size of the water softner depends on the amount of these two elements and the flow rate you require. The resin in water softners last aproximitaley 5 to 7 years. Once the resin has been fully saturated. The resin has to be regenerated (washed) this done with corse salt (brine) regeneration is about 1 hour long. This will regenrate the resin for normal use again. The salt container or brine tank needs to be topped up from time to time. At least 2 bars of pressure is required for this unit to operate eficiently. Automatic and manual vessels are available.

CARBON FILTERS

Used mainly for chlorine removal and other organic gases and to clear up the taste of water. CAUTION: bacteria breeds very well in carbon. If you are using carbon in a chlorine free system eg using carbon to clear up the taste of a borehole you will have more of a chance of bacteria build up. Solution use uv light. once carbon has been saturated the media must be replace. Carbon media has quite a large life span espcially if mixed with kdf. Change of media is dependant on flow and chlorine concentration. Large carbon filters still need to be backwash to clear sediment.

SAND FILTERS

Is used mainly for the removal of sediment from water. Depending on the size of your sand filter, flow rate and how much sediment is in the water. Will give you the intervals to backwash your sand filter. Normally the water flow comes to a stand still once unit is block. Automatic and manual sand filters are available. Manual sand filter are normally pool sandfilters

UV LIGHTS

Kills 99.9 percent of all known harmfull bacteria is very efficient. The water for treatment needs to be clean water not murky. The uv light cannot penetrate dirty water and will not work efficently. Your flow rate needs to be worked out so as to calculate maximum light contact time with water. If the water passes over the light to quickly it will not be effective. Different uv lights sizes are available for large flows. Lamp has a life span of aprroximatly 2 years. The unit needs to be installed correctly so water dose not drain out of unit when there is no flow. Heat damage may occur if installed incorectly. Uv lamp needs 2 mins warm up time before it is fully effictive is best if unit remains turned on at all times. Uv light needs to be installed as close to water outlet as possible so there is lees chance of bacteria getting through the system. Uv light kills on contact only.

REVERSE OSMOSIS (for more info click here)

OZONE

Kills 99.9 percent of known harmful bacteria. Extremily effective. Can be costly. Ozone is a toxic gas and should be removed at your last water outlet by a carbon filter. Ozone machines create ozone bubbles in water that kill off the bacteria. Can be used in dirty water muddy water. Bubbles must be distributed correctly for maximum effectivness. Bubbles can travel along your pipes to kill bacteria futher along the system. If not fitted correctly bacteria will get through. Ozone production dependant on size of machine and flow rate

HEIGHT VS PRESSURE

CHLORINE

Chlorine is used almost universally in the treatment of public drinking water because of its killing power of harmful bacteria and other waterborne, disease causing organisms. But there is a growing body of scientific evidence that shows that chlorine in drinking water may actually pose greater long term dangers than those for which it was used to eliminate.
These effects of chlorine may result from either ingestion or absorption through the skin. Scientific studies have linked chlorine and chlorination by products to cancer of the bladder, liver, stomach, rectum, and colon, as well as heart disease, atherosclerosis (hardening of the arteries), anaemia, high blood pressure, and allergic reactions.There is also evidence that shows that chlorine can destroy protein in our body and cause adverse effects on skin and hair.
The presence of chlorine in water may also contribute to the formation of chloramines in the water, which can cause taste and odour problems.
Since chlorine is required by public health regulations to be present in all public drinking water supplies, it is up to the individual to remove it at the point-of-use in the home.
It has also been discovered that chlorine reacts with organic material in water to produce hundreds of chemical by products, several of which have proved, in animal studies to be carcinogenic.

Known carcinogens are found in drinking water as a direct consequence of the practice of chlorinating. A long established public health practice for the disinfecting of drinking water.
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
Francis T. Mayo, Director.

Chlorine is the greatest crippler of modern times. While it prevented epidemics of one disease, it was creating another. Two decades ago, after the start of chlorinating our drinking water in 1904. The present epidemic of heart trouble, cancer and senility began.
SAGINAW HOSPITAL
Dr. J.M. Price, MD.

Cancer risk among people drinking chlorinated water is 93% higher than those whose water that does not contain chlorine.
U.S. COUNCIL OF ENVIRONMENTAL QUALITY