BOREHOLE WATER TREATMENT

Most people are looking for a much more affordable way to have water in their homes as having municipal water can be unreasonably costly.

Drilling a borehole can be costly but can offer a lifetime of cost savings.

Drilling a borehole does not mean you will always find water. There are dry wells that have been found through borehole drilling. Sometimes when you find water, the streams can run dry.

Key elements to successfully drilling a viable borehole are as follows:

• Due diligence with the drill point surveying
  • Borehole drillers make use of a number of techniques.
• Accurate drill set up and drill tempo
  • Simply pinpointing a potential drill site is not enough to guarantee a successful borehole. It is crucial that the drill rig operator has enough experience and knowledge to set up the drill rig properly and to maintain the correct penetration rate. This will ensure a stable and straight borehole which again vastly increases the potential for a successful borehole.
• Proper borehole construction
  • It is key that a drilling supervisor or consultant be onsite to ensure that the borehole construction is done safely and correctly. Casing installation, perforation, and depth can all influence the success rate.

There are many reasons why residential homeowners choose to invest in borehole drilling on their properties. When you own your water supply, you own your destiny. With a borehole, you say goodbye to frustrating water cuts, municipal disruptions, and water rationing during times of drought!

With a borehole on your property, you will save money every day. Water independence from municipal sources is another big reason behind boreholes’ popularity in South Africa.

In most areas throughout South Africa, there are no local water authority restrictions on the use of groundwater for domestic use. Some areas are underlain by dolomitic lithologies, however, do feature restrictions – Irene for example

When you invest in a borehole for your property, it also allows you to enjoy cultivating a beautiful garden for less, and also keep the garden beautifully green and luscious in a Drought.

Boreholes also offer greater water security and add tangible value to your property.

It is very crucial that you get your borehole water tested. The reason for this is to check if the water is fit for human consumption.

Most boreholes contain a lot of contaminants in their water and knowing the levels/number of the contaminants is very important. This will help you and us determine the type of solution required to produce the best quality water.

Natural water contains heavy metals that can be harmful to your health or might cause health problems in the future unless treated.

Most water tests report the following heavy metals in water and the type of treatment required;

• pH @ 25°C pH
• Electrical conductivity (EC) @ 25°C mS/m
• Total dissolved solids (TDS) @ mg/l
• Total alkalinity @ mg CaCO3/l
• Chloride (Cl) @ mg/l
• Sulphate (SO₄) @ mg/l
  • Sulfate (SO₄) can be found in almost all natural water. The origin of most sulfate compounds is the oxidation of sulfide ores, the presence of shales, or industrial wastes.
  • Sulfate is one of the major dissolved components of rain. High concentrations of sulfate in the water we drink can have a laxative effect when combined with calcium and magnesium, the two most common constituents of hardness. Bacteria, which attack and reduce sulfates, form hydrogen sulfide gas (H2S).
• Nitrate (NO₃) as N @ mg/l
  • Nitrates level in drinking water is recommended below 50 mg/L, especially for babies. Indeed, their digestive systems are immature, and thus more likely to allow the reduction of nitrate to nitrite. The nitrite in the digestive tract of babies can cause methemoglobinemia.
    Nitrates can be removed by ion exchange using strong anionic resin in Cl- form.
    Reverse Osmosis is also efficient to remove nitrates, although the hydrophilic properties of the molecule do not allow an optimal removal.Biological denitrification is used in the municipal wastewater treatment plant.
• Ammonium (NH4) as N @ mg/l
• Fluoride (F) @ mg/l
• Calcium (Ca) @ mg/l
  • Calcium is naturally present in water. It may dissolve from rocks such as limestone, marble, calcite, dolomite, gypsum, fluorite and apatite. Calcium is a determinant of water hardness because it can be found in water as Ca2+ ions. Magnesium is the other hardness determinant.
  • Removing calcium and magnesium ions from water is carried out by water softeners. These are ion exchangers that usually contain Na+ ions, which are released and substituted by Ca2+ and Mg2+ ions.
  • Calcium compounds may be applied for wastewater treatment. Drinking water pH and hardness may be altered by means of calcium carbonate and calcium hydroxide.
• Magnesium (Mg) @ mg/l
  • Magnesium is present in seawater in amounts of about 1300 ppm. After sodium, it is the most commonly found cation in oceans. Rivers contain approximately 4 ppm of magnesium, marine algae 6000-20,000 ppm, and oysters 1200 ppm.
  • Magnesium and other alkali earth metals are responsible for water hardness. Water containing large amounts of alkali earth ions is called hard water, and water containing low amounts of these ions is called soft water.
  • Magnesium compounds are usually removed from the water, because of the role magnesium plays in water hardness. This is achieved by means of water softening.
  • Magnesium hydroxide is applied as a flocculant in water purification.
• Sodium (Na) @ mg/l
  • For billions of years, sodium is washed out from rocks and soils, ending up in oceans, where it may remain for about 50.106 years. Seawater contains approximately 11,000 ppm sodium. Rivers contain only about 9 ppm.
  • Drinking water usually contains about 50 mg/L sodium. This value is clearly higher for mineral water. Insoluble form sodium always occurs as Na+ ions.
  • To remove sodium chloride from water, one may apply reverse osmosis, electrodialysis, distillation techniques, or ion exchange. Reverse osmosis is most economical considering energy and money requirements.
  • Sodium is applied in water purification. It may function as a counter ion of calcium and magnesium in water softeners. Caustic soda and sodium percarbonate are applied to neutralize acids. Sodium bisulfite (NaHSO3) is applied as a reduction for strongly oxidizing chemicals, sodium sulfide (Na2S) for precipitation of complexed metals.
• Potassium (K) @ mg/l
  • Potassium occurs in various minerals, from which it may be dissolved through weathering processes. Examples are feldspars (orthoclase and microcline), which are however not very significant for potassium compounds production, and chlorine minerals carnallite and sylvite, which are most favorable for production purposes. Some clay minerals contain potassium. It ends up in seawater through natural processes, where it mainly settled in sediments.
  • Potassium may be removed from water by means of Reverse Osmosis. Potassium is applied in water purification. For example, potassium permanganate is applicable for the oxidation of waterborne compounds, such as for iron or manganese removal, and disinfection. This is however not generally recommended. Potassium permanganate application makes it possible to determine the oxidative capacity of organic matter in water. Generally, this exceeds BOD. Potassium dichromate is applied for COD determination.
• Aluminium (Al) @ mg/l
  • The amount of aluminum in seawater varies between approximately 0.013 and 5 ppb. The Atlantic Ocean is known to contain more aluminum than the Pacific Ocean. River water generally contains about 400 ppb of aluminum.
  • Aluminum mainly occurs as Al3+ (aq) under acidic conditions and as Al(OH)4- (aq) under neutral to alkaline conditions. Other forms include AlOH2+ (aq) en Al(OH)3 (aq).
  • Aluminum may be removed from water by means of ion-exchange or coagulation/ flocculation. Aluminum salts are applied in water treatment for precipitation reactions. Adding aluminum sulfate and lime to water causes aluminum hydroxide formation, which leads to the settling of pollutants. Hydroxide is water-insoluble, therefore only 0.05 ppm dissolved aluminum remains. This is below the legal limit for drinking water of the World Health Organization (WHO), of 0.2 ppm aluminum.
• Iron (Fe) @ mg/l
  • Iron in rural groundwater supplies is a common problem: its concentration level ranges from 0 to 50 mg/l, while the WHO recommended level is < 0.3 mg/l. The iron occurs naturally in the aquifer but levels in groundwater can be increased by the dissolution of ferrous borehole and handpump components. Iron-bearing groundwater is often noticeably orange in color, causing discoloration of laundry, and has an unpleasant taste, which is apparent in drinking and food preparation.
  • Depending on the levels of Iron, we normally recommend DMi-65 Iron removal media to reduce/remove the Iron from the water. For DMi-65 to be able to perform such, it first needs to be activated. How do you activate it, you ask? You will need to use chlorine to activate the DMi-65 media.
  • DMI-65 is designed to operate in the presence of chlorine or another oxidant. In this process the oxidant removes electrons and is consumed in the process. The operator needs to ensure that there is a 0.1 – 0.3 ppm free chlorine residual in the effluent water. Chlorine, fed as sodium hypochlorite or bleach (12.5% NaOCl), is the preferred oxidant since it is relatively inexpensive, readily available around the world and it is effective. It also performs the vast majority of any disinfectant process.
  • How to remove the sulfate from your water
    There are three types of treatment systems that will remove sulfate from your drinking water: reverse osmosis, distillation, or ion exchange. Carbon filters, water softeners and sediment filters will not remove sulfate. Water softeners exclusively change magnesium or calcium sulfate into sodium sulfate, which is more laxative.
  • Reverse osmosis (RO) is a water treatment system that eliminates most dissolved elements and chemicals, such as sulfate, from water by pushing the water through a plastic surface similar to cellophane known as a “semipermeable membrane.” Generally, it can eliminate between 93 and 99 % of the sulfate in drinking water. This depends on the type of unit.
  • A small RO unit will produce about 12 liters of water per day. A little larger unit, normally installed under the sink, will produce 19 to 75.6 liters of water per day. RO units generally produce only 3.8 liters of water for every 15 to 38 liters of water treated. The remaining water is rejected.
• Copper (Cu) @ mg/l
• Turbidity NTU
• Total hardness @ mg CaCO₃/l