Various types of organic matters, such as humic substances a range of hydrocarbon derivatives,  are present in Hungarian water sources (both artesian and thermal ones), in particular in those of the Dél-Alföld (Southern Hungary) region. 

In most instances, different water treatment technologies are used to deal with these organic compounds.  These technologies involve the application of some sort of disinfection process. In Hungary, disinfection processes are almost exclusively based on chlorine or various types of chlorine-containing chemicals. The used (spent) waters also require treatments (i.e., wastewater treatment) and are deposited in the environment (i.e., passed to rivers, lakes or reservoirs)

In the course of the water treatment, the role of chlorine is (i) the oxidation of substances contributing to the odor, taste or color of the water, (ii) inactivation of bacteria, viruses or other potentially hazardous micro organisms, (iii) removal of ammonia and (iv) preservation of the microbiological quality of the treated potable water.

To avoid unwanted side-effects, alternative water treatment technologies, e.g., ozonation, are used, but (due to the short term effect of ozonation), further chlorination steps are necessary.  Removal of organic components from water can efficiently be done by using activated carbon treatment, but this technology is very expensive. The expenses are associated with the high cost of the sanitary quality activated carbon, with the costly regeneration process of the spent carbon bed, and with the deterioration of the mechanical properties of the activated carbon during use (i.e., the carbon bed becomes “packed” which increases its flow resistance and decreases energy efficiency.)

The current environmental legislation in Hungary introduced strict regulations in relation to spőent thermal water contaminants. This obviously highlights the necessity of updating the old-fashoned methods and developing new and more efficient spent thermal water treatment technologies. The most recent results from Europe’s leading research laboratories unambiguously point out, that target-oriented chemical methods based on the selective elimination of specified chemical compounds may lead to the development of a new generation cost-efficient and revolutionarily new treatment technologies.

In our efforts, an economic and efficient solution for the problem outlined above is proposed, which is based on the development of a novel flocculation technology using a new flocculent. Conventional flocculants (e.g., poly-aluminum chloride, PACl) are suitable for removing suspended contaminants and polar (i.e., well-adsorbing) organic compounds, but largely inefficient for non-polar organics with relatively low molecular weight.  According to our concept, the costly activated carbon treatment will be substituted with one of the following methods:

• Modification of the conventional PACl flocculants by the use of a composite mixture of PACl and compound(s) selectively adsorbing non-polar organic matter from waters;
• Rapid, efficient and economic chemical transformation of the target compounds by using advanced oxidation processes (i.e., generating highly reactive radicals) resulting in higher polarity and better adsorption ability of the transformed compounds to PACl;
• The optimal combination of the two methods mentioned above; 

Thermal waters have high ion content, and in some cases, a high concentration of organic (sometimes toxic) compounds. Such contaminants may damage the life of natural (stagnant) waters used as reservoirs for these residual waters.

1. It is well documented in the literature, that flotation is not suitable for efficiently removing toxic organic compounds from thermal waters.
2. However, activated carbon treatment could result in the hygienic quality of drinking water.
3. Most frequently, membrane separation processes (i.e., ultrafiltration, nanofiltration and reverse osmosis) are used for the removal of salinity. However, such techniques have the drawbacks of poor removal of low Mw (organic) materials (ultrafiltration) and a high energy consumption (reverse osmosis).
4. Ozonation is considered to be one of the most promising processes to control the levels of organic pollutants in water and it can be used for the removal of inorganic species, as an aid to the coagulation-flocculation process.
5. When ozonation was applied in combination with ultrafiltration, the flux was found to be largely dependent on the quality of the raw water: in waters containing appreciable quantities of suspended materials, preozonation caused the membrane flux to decrease, whereas in clear waters, the flux increased.