Physical/Chemical Treatment of Industrial Waste Water
Eisenmann develops and builds made-to-measure plants for the physical/chemical treatment of industrial waste water. These include:
- Precipitation, flocculation, sedimentation
We provide planning, design and installation services for physical/chemical treatment plants, turnkey solutions, and BOT models in line with your specific needs.
Schematic of the Eisenmann Fentox® process
Industrial waste water is frequently contaminated with inorganic substances (above all cyanide, chromate, arsenic and nitrite.) To remove them from the effluent a variety of decontamination methods can be employed.
Eisenmann uses the patented Fentox® process for this purpose. This oxidizes toxic organic compounds with a solution of hydrogen peroxide and a ferrous iron catalyst (Fenton’s reagent). This method is not only advantageous from an engineering point of view, it also requires less hydrogen peroxide. Our UV Fentox® method is suitable for very high COD loads. With this method, less Fe(II) is required and the sludge quantity can be significantly reduced.
Precipitation, Flocculation, Sedimentation
Precipitation, followed by flocculation and sedimentation, is a long-established and proven physical/chemical process for treating industrial waste water. It is mainly employed for the removal of heavy metals, fluorides and phosphates.
During the precipitation stage, neutralizers (acid/lye) and special precipitation agents are added, and insoluble compounds are formed at specific pH values. Precipitation is followed by flocculation aided by flocculants. This enables the effective removal of harmful substances from the waste water. The sludge produced in the previous process steps is separated from the waste water by means of sedimentation.
Flotation is used to treat industrial waste water that contains substances that tend to float to the surface. These include paint, oils, grease and carbohydrates. Flotation is facilitated by the addition of chemical agents and the injection of air (dissolved air flotation). The dirt particles adhere to the air bubbles and rise with them to the surface, where the floating matter can be skimmed off. The sludge produced by flotation is further dewatered in dewatering containers, chamber filter presses or decanters.
Applying Membrane Processes in the Treatment of Industrial Waste Water
Eisenmann ultrafiltration plant for emulsion splitting
Eisenmann develops and builds made-to-measure facilities for the treatment of industrial waste water by means of membrane processes. These are used for splitting emulsions, removing paint pigments or tensides, and for desalination.
Eisenmann employs membrane processes in a wide variety of applications. In the automotive and metal industries, for example, ultrafiltration is mainly used for emulsion splitting. Waste water produced by surface degreasing contains greases and oils that may be easily removed from water by means of membrane processes.
Membrane filtration is also used to treat paint waste water. Pigments can be effectively concentrated via ultrafiltration, producing clean filtrate. In some instances, pigments can even be recovered from the concentrate.
Combined ultra- and nanofiltration for the treatment of printing ink waste water
One application of nanofiltration is the recovery of tensides from degreasing baths. The tensides are concentrated by this method and can be returned to the degreasing bath in order to conserve resources.
Industrial-scale reverse osmosis is primarily used to produce deionized (DI) water, which is required in a large number of industrial processes. Reverse osmosis is also employed for treating boiler feed water and seawater.
Membrane processes are also used to treat waste water in advance of physical/chemical treatment methods. A combination of different membrane processes can be used to treat more highly contaminated waste water, such as residues from biogas plants or printing ink waste water.
Eisenmann operates test plants for waste water treatment. We use them not only to optimize or develop our own products but also to resolve problems for our customers or for trials at the customer site. Talk to us!
Biological Processes for Industrial Waste Water
Biological processes used for the treatment of industrial waste water are either aerobic (in the presence of oxygen) or anaerobic (in the absence of oxygen). Anaerobic processes entail fermentation of organic content by microorganisms, producing energy-rich biogas. No energy is required for the air supply, and also very little excess sludge is produced. However, not all organic compounds can be treated anaerobically, which is why there is often a subsequent aerobic process.
Eisenmann offers customers a truly end-to-end solution for treating biological waste water, including the Pyrobustor® for the thermal treatment of sewage sludge.
Applications of Biological Processes for the Treatment of Industrial Waste Water
Outdoor biological treatment system for industrial waste water
Combined aerobic processes
The manufacture of TV tubes generates waste water contaminated with both organic and inorganic pollu-
tants. For this application, Eisenmann designed a plant with an aerobic biological process for treating the organic pollutants and a separate, physical-chemical precipitation stage for the inorganic contaminants.
For the aerobic stage, a membrane bioreactor (MBR) under aerobic conditions with high sludge age was used. This high-performance process produces minimum excess sludge. The waste water contaminated with inorganic compounds is pre-treated by flocculation and sedimentation and the pollutants subsequently removed by detoxification, followed by precipitation. They can then be directly discharged into the river via gravel filters.
Anaerobic biological process with rotating disc filters
Combined anaerobic processes
In collaboration with the Fraunhofer Institute, Eisenmann has developed a process for the anaerobic treatment of waste water. The central element is an anaerobic MBR with an Eisenmann rotating filter which completely re-
moves the adapted microorganisms from the treated wa-
ter. As a result, a large proportion of the energy contained in the waste water in the form of organic compounds can be converted to biogas, with minimum excess sludge production. Ultrafiltration reclaims the phosphate and ammonium, which are dissolved in the solids-free clarified waste water, for use as fertilizers. Furthermore, the purified water can be reused in a variety of ways.
Industrial Waste Water Recycling
Schematic of a waste water-free pretreatment
Prevention and reutilization are preferable to disposal. Against this background, recycling technologies have top priority when it comes to treating industrial waste water. From the planning and design stages, Eisenmann focuses on exploiting every opportunity to conserve and recycle water.
In many industries, a combination of resource recovery and waste water treatment can deliver a rapid return on investment (e.g. for environmental technology plants). For example, deploying an evaporator can eliminate waste water from a pre-treatment system. The waste water is evaporated and the distillate recycled, i.e. reused in the pretreatment process. That means a number of regulatory requirements and inspections no longer apply.
Waste water recycling in the printing ink industry
Another form of waste water recycling is DI water (deionized water) recirculation, e.g. at the DI water rinsing stations in pretreatment plants. This reduces freshwater consumption.
Waste water recycling frequently involves multiple treatment processes. For treating toxic waste water, for example, the Fentox® process can be combined with a biological process that causes the inhibitory substances in the water to become bioavailable. Often, a physical-chemical stage for the precipitation of inorganic compounds is followed by a biological process to remove the organic compounds. Another common configuration is a chemical-physical treatment process in conjunction with a membrane technique for reliably separating very fine particles. In accordance with the customer’s requirements and the possibilities offered by the site, these systems can be run with full or partial recirculation.
Our environmental technology specialists understand a wide range of applications, and can help you select the most suitable combination of processes for your needs, taking regulatory requirements and local conditions into account.