In several locations around the country, various substances in the groundwater pose difficult challenges at specific water treatment plants. These challenges require special decontamination technology. Kemic Water Technology has many years’ experience of designing and manufacturing systems for handling problematic water.
The content of particular elements in the Danish subsoil poses challenges for some waterworks around the country. Raw water from boreholes can be difficult to filter if it contains hydrogen sulphide, methane, arsenic, Co2, NVOC and iron-humic complexes. A different kind of water treatment is required if these substances are present.
Special purification technology
In many locations, it is the combination of substances in the boreholes that requires special purification technology. Major fluctuations in the volume of water pumped out and atypical water quality are often seen in areas near the coast. This imposes demands on the design of the filtration system.
Kemic Water Technology designs and manufactures systems to suit the geographical location of each waterworks. We take into account the type of raw water and the natural geological occurrence of various elements in the groundwater.
Arsenic content in groundwater varies, and arsenic content in Denmark depends on geographical location. Arsenic is a harmful substance and there are several methods for eliminating it from the groundwater at Danish waterworks.
One of the methods is to merge boreholes to comply with threshold values for drinking water. If a water treatment plant has more than one borehole, and some of these boreholes contain large quantities of iron, the boreholes can be merged using the treatment plant’s control system to ensure that the recommended threshold values are complied with once treatment is complete. A natural process is used to remove arsenic from drinking water and no permit is required.
Another method for complying with threshold values is enhanced water treatment. If a borehole has a very high concentration of arsenic in the water, it will be necessary to add iron sulphate or to use a filtering medium with a high content of iron. Both the addition of iron sulphate and a ferrous filtering medium require careful monitoring and separate treatment systems. Enhanced water treatment also requires a permit.
Kemic Water Technology has been supplying systems for eliminating arsenic from drinking water for many years. Kemic Water Technology has also participated in a number of research and pilot projects related to removal of arsenic from drinking water.
Raw water with methane and hydrogen sulphide
Methane and hydrogen sulphide are found in the groundwater in many locations in Denmark. Methane and hydrogen sulphide are formed when organic substances are broken down under deoxidised conditions. Boreholes with occurrence of methane and hydrogen sulphide require special aeration and purging to remove the gases from the water before it is piped into the sand filters. The water is aerated with powerful aeration system in pressure vessels. Both methane and hydrogen sulphide can occur in boreholes, but they can also occur separately.
Kemic Water Technology has been supplying aeration and purging systems for elimination of methane and hydrogen sulphide for many years.
Raised NVOC and colour values
High content of organic matter in the groundwater, humus and iron, will give raised levels of NVOC and higher colour values. One way of stabilising NVOC and the colour value is by enhanced water treatment.
Kemic Water Technology has been supplying various forms of enhanced water treatment for many years and is constantly striving to develop in this field.