Technology

Dissolved air flotation

Flotation is the most effective method of removing contaminants such as fats, suspensions, oil-derived substances and other undissolved substances found in industrial wastewater. The separation of these contaminants takes place in chemical processes using coagulants and flocculants (polymers). After separation, separation takes place using a water-air mixture in the flotation chamber. The resulting sludge is discharged outside the system and possibly dewatered before being disposed of, e.g. in a biogas plant.

Technology

Mechanical pretreatment

Most industrial wastewater streams contain solids that must be removed before wastewater reaches the treatment plant equipment. Removal of solids is necessary to protect pumps, mixers, sensors and other system components from blocking or even damage. In EMI installations, we use two stages of mechanical pre-treatment: coarse and fine. Coarse pre-treatment removes the largest elements, with a cross-section above 20 mm, and is carried out at the inlet to the first pumping station, before wastewater comes into contact with any pump. Coarse separation devices include vertical screens, basket screens and step/hook screens. The purpose of fine mechanical pre-treatment is to further remove solids, with their cross-section dropping below 3 mm, most often to 1 mm, although in some cases it is appropriate to use even smaller cross-sections (up to 0.25 mm). At this stage, rundown and rotary screens are used. The latter type of screen is used in a system with external or internal inflow. Mechanical pre-treatment involves very low costs, mainly resulting from the consumption of water rinsing the screens. No reagents are used, and energy consumption is minimal. Mechanically pre-treated wastewater is suitable for further treatment by physico-chemical and biological means.

Technology

Flow biological reactor

The classic flow biological reactor, also known as activated sludge reactor, is a wastewater treatment system based on the biological decomposition of pollutants by microorganisms. The process begins with the introduction of sewage into an aeration chamber, where it is mixed with activated sludge containing microorganisms. In this chamber, the sewage is aerated, which provides the oxygen necessary for the activity of microorganisms that decompose organic pollutants. Then the mixture of sewage and sludge flows into a secondary settling tank, where sedimentation takes place, i.e. separation of purified water from sludge. The purified water is discharged for further treatment or to a receiving water body. Part of the sludge is recirculated back to the aeration chamber to maintain the appropriate number of microorganisms, and excess sludge is removed. This cycle provides continuous and effective wastewater treatment, using natural biological processes.

Technology

Sludge dewatering

Dewatering of sludge generated during the treatment of industrial wastewater is a key process aimed at reducing the volume of sludge and improving its properties for further processing or disposal. This process involves removing as much water as possible from sludge, which is achieved using various methods, such as centrifuges, filter presses or vacuum dewatering. The main goal of dewatering is to reduce the mass and volume of sludge, which translates into lower transport and storage costs. Dewatered sludge also has better mechanical properties, which facilitates its further processing, such as composting, incineration or biogas production. Additionally, reducing the water content in sludge minimizes the risk of leaks and environmental pollution. The dewatering process can also increase the efficiency of further treatment stages, for example by improving the conditions for anaerobic digestion. Thanks to sludge dewatering, the process of treating industrial wastewater becomes more economical and environmentally friendly.

Technology

Equalization

Wastewater in industrial plants is generated in many places and in many processes. As a result, its quantity and composition fluctuate significantly during the day and sometimes many days. Adjusting the treatment process to rapidly changing wastewater would be inefficient and uneconomical. Therefore, in industrial installations we use equalization tanks of appropriate size and equipment. We select the size based on data from the plant, industry knowledge and our own experience. The equipment of equalization tanks may include pumps, mixers, aeration systems, neutralization systems, by-passes and additional interceptor tanks and many other elements carefully selected to meet the requirements of individual cases.

Technology

Neutralization

Ensuring the appropriate pH value in sewage is very important for two reasons. Firstly, each receiver (sewage system, environment) requires that the sewage directed to it has a pH within a predetermined range. Secondly, the sewage pretreatment and purification processes themselves require ensuring their appropriate pH. Emi offers a wide range of solutions, from simple systems with one measurement and dosing of one neutralizing agent to complex, multi-stage systems requiring the use of specific neutralizing agents. pH correction can take place at many levels, stages and in one of two modes: flow (online) or batch.