Our Clear Water Unit is designed for the treatment of groundwater, especially where turbidity is a problem and where organic compounds and tannins cause the discolouration of the water by remaining in suspension.

This unit is also highly effective at removing Iron, Manganese and Boron from groundwater!

Lime treatment offers the most cost effective way to treat your groundwater, using a dry powder called Hydrated Lime Ca(OH)2 (calcium hydroxide) mixed into suspension inside a dosing tank, the unit is calibrated to inject the desired amount of lime milk into the incoming water tank.

A pressure pump cycles on during the dosing process to agitate and suspend the lime solution (lime milk) for dosing as the precipitation tank is filled, so the entire process is fully automated.

Hydrated Lime is by far the most economical way of treating groundwater and is readily available as a dry powder throughout South Africa.

Advantages

• Chemical Coagulation
• Precipitation
• pH Adjustment
• Stablilization of sludge

Benefits

• Increases Alkalinity.
• Controls bacterial growth.
• Removes Manganese.
• Removes Flouride.
• Removes Organic Tannins.
• Removes Iron.
• Water Softening

Water Softening

Lime softening is a water treatment process that uses calcium hydroxide, or limewater, to soften water by removing calcium and magnesium ions. In this process, hydrated lime is added to the water to raise its pH level and precipitate the ions that cause hardness. The lime softening process offers many benefits, including the reduction of dissolved minerals in the water and the reduction of heavy metals and other elements such as barium, arsenic, and uranium that naturally exist in some water sources.

The functions of lime in water treatment (Calcinor)

Lime in all its forms – quicklime and hydrated lime, as well as calcined dolomite - are the most effective and cost efficient alkaline products used in the making of drinking water, as well as in the treatment of waste water and sludge. In fact, most of the lime that is produced is used to improve the quality of drinking water as well as the water used by industry. Accordingly, lime allows water to be softened, purified, have its cloudiness eliminated, its acidity to be neutralized and its impurities to be eliminated.

Thanks to the use of lime in water treatment plants an improvement in the taste, smell and colour of the water is achieved, among other benefits, because suspended matter is eliminated, and therefore any cloudiness is eliminated. Moreover, manganese, fluorides and organic tannins are also eliminated along with the afore-mentioned silica.

One of the most important features in this type of application is that of disinfection. When lime is added to water to take the pH up to between 10.5-11.00 for a period of between 24 to 72 hours it is possible to lower the quantity of bacteria and viruses in it, at the same time most of the heavy metals dissolved in it are also eliminated.

In the same way, the pH of the water can be adjusted, via the use of lime milk, until it becomes suitable for its subsequent treatment in the drinking water plant.

The former is a case of water with an acidic nature, that is with a low pH. This could be because of the local geology, but can also be caused by human influence. To avoid possible side-effects from the consumption of this type of soft-water, it is necessary to adjust the calco-carbonic balance, that is to control the pH with simultaneous softening.

On the other hand, if it is necessary to lower the hardness of the water it can be subjected to a process of decarbonation, avoiding precipitates and the incrustation of calcium-carbonate. For this application, the chemical products used are calcium-oxide (CaO) or calcium hydroxide (Ca(OH)₂), added in suspension (lime milk) or dissolved (lime water), bringing about the precipitation of the calcium as calcium-carbonate and magnesium as hydroxide, achieving a reduction in the number of calcium cations and the dissolved magnesium concentration.

Waste water

In the case of conventional chemical treatment of industrial inorganic waste waters, lime has several advantages: control of the pH, neutralization of acidic waste water, a reduction in the concentration of oxidizable organic pollutants, clarification, precipitation of dissolved pollutants as well as flocculation and coagulation of colloidal particles.

The use of lime in waste water treatment plants for the elimination of organic sludge became widespread over 100 years-ago. Nowadays the most widely used lime product in Waste Water Treatment Plants (WWTP) is calcium hydroxide (Ca(OH)₂), with a purity of more than 90%.

Several advantages are provided by the application of lime in these plants, both in the water line (precipitating toxic metals and lowering the level of suspended solids) as well as in the sludge line (conditioning all type of sludge, stabilizing it without it becoming contaminated, eliminating bad smalls and destroying pathogenic agents, making it more hygienic).

Further Reading: The Suez Water Handbook