Chemical treatment of waste water and water

Electrochemical wastewater treatment

Electrochemical processes are becoming increasingly important in wastewater treatment. The use of chemicals and fossil fuels can be reduced with the help of electrochemical processes. In our specialist group, we are investigating the treatment of wastewater with a high nickel content by electrolysis, electrochemical nitrite oxidation, the basic recovery of phosphorus from sewage sludge by electrochemical struvite precipitation and the elimination of micropollutants by anodic oxidation (see Advance Oxidation Processes). Electrochemistry also enables a variety of other processes such as electrocoagulation or the electro-Fenton process.

Water disinfection

Water can become a breeding ground for dangerous pathogens such as bacteria (e.g. legionella), viruses and protozoa. These can be removed sustainably by taking appropriate measures. We are researching the use of various disinfection methods such as chlorination, electrochlorination, ozonisation and UV irradiation. Together with the physics department, for example, we are investigating the use of UVC LED flow reactors. UVC refers to the short-wave range of UV radiation with a wavelength of 100 - 280 nm. This radiation can kill microorganisms in water, but also in the air, thus preventing the spread of diseases.

Physics Group: UVC (DE)

Advanced Oxidation Processes (AOP)

In advanced oxidation processes (AOP), highly reactive oxygen species such as hydroxyl radicals (OH-) are used to break down organic contaminants. AOPs are often used when conventional purification processes are not sufficient to remove persistent or toxic compounds (e.g. micropollutants such as pharmaceuticals or pesticides). In our specialist group, we investigate the use of ozone as an oxidising agent and the electrochemical generation of radicals (anodic oxidation by electrolysis) for the removal of organic substances in general and micropollutants in particular from municipal and industrial wastewater.

Factsheet Electrolysis (DE)

Lime

Calcification can lead to restrictions in the functionality of water pipes, boilers and various household and industrial appliances. A wide variety of devices are therefore available on the market that are designed to protect against limescale. It is often difficult for the layman to distinguish between reputable and dubious products. Especially in the field of physical water treatment devices, there are many providers who exploit the ignorance of users to sell an ineffective device for a lot of money. Glossy brochures describe effects that are not proven and do not stand up to independent scrutiny. We can advise you and help you find the right device.

Factsheet Limescale Protection (DE)   Investigation PWBG (DE)
 

Adsorption of heavy metals

Heavy metal contamination occurs in road runoff, industrial wastewater and leachate from polluted sites. Adsorbers or zeolites can be used to bind heavy metals and thus reduce their content in water. An important example is the leachate (seeping rainwater) from bullet traps at shooting ranges with high concentrations of lead, copper and antimony originating from the bullets. The seepage water is therefore collected and then freed from the heavy metals. As antimony is difficult to adsorb using conventional methods compared to other heavy metals, we are researching new approaches to adsorption.

Flocculation and coagulation

During flocculation, fine particles in the water are brought together into larger agglomerates by adding flocculants so that they can be removed from the water more easily. The coagulant plays an important role here by neutralising the electrical charge of the particles, making them less repulsive. The resulting flocs can then be removed from the water by sedimentation, flotation or filtration. By using modern flocculants and coagulants as well as optimised process control, we develop customised solutions for wastewater treatment.

Odour inhibitor

Hydrogen sulphide (H₂S) is a corrosive, toxic and strong-smelling gas that is formed by microorganisms in drainage systems (sewerage and intermediate storage tanks). The formation and release of the gas can be prevented by dosing oxidising agents (e.g. nitrate) or precipitating agents (e.g. iron salts) into the drainage system. Dosing at the right place and in the right quantity is decisive for the success of the measure. As specialists in chemical wastewater treatment and odours, we investigate where and in what quantities odour inhibitors can be optimally dosed. This saves resources.

Factsheet Sewer Odours (DE)       Factsheet Odour Inhibitor (DE)