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Eco Plants in Waste Water Treatment and Industrial Sector


As part of our service in the industrial sector, we can offer preliminary design and supply of equipment and machinery for wastewater treatment, oily waste in refineries and industry, technological wastewater, as well as wastewater from treatment at county waste management centers, together with complete plant construction , assembly, commissioning and maintenance.

Company representer:


Machinery and plants for treatment

As part of our service Ecological Industrial Plants, company Com-ing Trade offers you planning, engineering, supply of machinery and plants for treatment of:

  • waste water,
  • slop oil waste in refineries,
  • county waste management centers,
  • technological water in the process of food industry.

Waste Water Treatment Plant

Dehydration unit

A short description of operation

Waste Water Treatment Plant

Continuous growth of population and settlements, and thus the standard of population combined with the constant reduction of water resources on our planet, leads to an increase in by-products such as increased waste and other types of pollution. By increasing human consciousness towards the environment, there is concern about the exploitation and disposal of waste and the waste water that has the most for the purpose of disposal, purification and re-use of such waters, and for this purpose are built wastewater treatment plants.
A sewage network through the pumping stations of waste water is collected on a wastewater treatment plant. The diagram above shows schematically one such plant. On such a wastewater plant, eastewater pass first through a rough grate, where solid waste is separated from the liquid. After that it passes through the primary and secondary tank for eraction and blowing. In the secondary tank, a part of such water is brought to the extent that it can be released into the environment, while the rest of the waste water goes to the precipitation where the waste water is adding the nutrients that break down the sludge and prepare it for dehydration.

PIERALISI technology and these decanters have proved to be very successful at this stage of wastewater treatment – dehydration, both in the world and in Croatia and in the neighboring countries where we are represented. Before the sludge goes to dehydration, it is necessary to measure the dry solid sludge input concentrations and select and prepare a polyelectrolyte that is necessary for better separation and obtaining greater dry solid outlet. When the polyelectrolyte is prepared, it is necessary to start the decanter and the sludge prepared for dehydration through the supply pumps is mixed before entering the polyelectrolyte in decanter in the mixer and that mixed sludge is entering in the decanter. In the decanter, the sludge separates through the gravitational force, where an aqueous film and a slip film are formed, and the water flows to the water side, and the dry dehydrated sludge on the opposite
side. The dehydrated sludge, after exiting the decanter, enters the screw conveyors where it enters the containers. Thereafter, such dried sludge is taken to the foreseen dump or incinerator. Depending on the capacity of the decanter, the concentration and quality of the input sludge and the well-chosen polyelectrolyte, the sludge yields up to 25%. The water coming out of the decanter goes to further purification in order to lower the BPK and KPC to
the appropriate measures, and purify it into streams, rivers, seas where as such it is unsuitable for the environment or reused for some other washing functions.

Technical description

Pieralisi dehidration unit


jedinica za pripremu polielektrolita

Polyelectrolyte is an additive used to better thicken and dry of the inlet sludge, and before use, it must be diluted depending on whether it is liquid or powdered polyelectrolyte and how much concentration of polyelectrolyte will work on the decanter. The polyelectrolyte is selected depending on the type and percentage of dry solid at the incoming sludge that is going to be treated.

The PIERALISI automatic polymer preparation unit is designed to work with both types of polymers (powder and liquid) depending on the type of sludge and what more end users practice.

The PIERALISI automatic powder polyelectrolyte preparation unit is consists of a tank for powdered polyelectrolyte with dispenser, water and powder mixer and a tank for dilute polyelectrolyte capable of 700 l, 1700 l and 3500 l.

The PIERALISI automatic liquid polyelectrolyte preparation unit is consists of a small pump with a manual inverter to which is connecting a liquid polymer, a water and liquid mixer and a diluted polyelectrolyte tank capable of 700 l, 1700 l and 3500 l.


Dobavne pumpe

They are used to supply sludge and polyelectrolyte’s into the decanter and are selected depending on the type of sludge / polyelectrolyte and the decanter capacity.


Centrifugalni ekstraktor - dekanter

A decanter is a machine for separating solids from a liquid, who is separating the liquid and solid phases by centrifugal force. Separation – sludge dehydration occurs inside the decanter.
One side enters mixed sludge containing a certain percentage of impurities and
polyelectrolyte. With the help of centrifugal force, a sludge film and a water film are created in the decanter. On one side, relatively clean water is released, which goes for further treatment to lower the BPK and KPK values to minimum values, and thus the purified water can be released into the environment. On the other side comes the solid phase – the dehydrated sludge and it drives to the intended landfill. Depending on the type of sludge, biogas can be extracted from the dehydrated sludge.

PIERALIS decanters are programmatically designed to reach maximum rpm with as little starting load as possible, and are also programmed that during shutting down are going in automatically washing so that the old solidified sludge does not remain on the next start.



They serve to transport dehydrated sludge from the decanter to the container or intended landfill.


mjeraci protoka

With the help of a flowmeter, it is known at all times how much sludge and polyelectrolyte enter the decanter.


glavni upravljacki elektro ormar

It is used to control the entire dehydration unit and all electric motors. The touch screen can control and monitor the speed, torque and voltage on the decanter, pump flows, parameters for better and easier operation of the entire wastewater treatment unit and operating hours.

It is also possible to establish communication but not management with the user SCADA system, and it is possible to see at any moment whether and how the system works.

Contact us

If you need treatment for oily waste, process wastewater, municipal wastewater as well as leachate after recycling and solid waste treatment, please contact us.

Company representative: GRUPPO PIERALISI




Domovinskog rata 56

21000 Split
OIB (VAT): 82264872162
MB: 03508722


Put Supavla 1,
(Jadnransko osiguranje building, 1st floor)
21000 Split

+ 385 21 361 470
+ 385 21 381 345
+ 385 21 322 242
Fax: + 385 21 322 243
GSM line:
+ 385 98 265 486
+385 99 23 54 090
+385 99 21 61 570

E-mail: jmladinic@com-ing.hr

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