These treatment plants are produced in circular tanks for 5 and 8 inhabitants.

The treatment plants are designed for an inflow depth of up to 0.7 m below ground level. The technology can be installed in any tanks and therefore it is commonly used for the reconstruction of other types of treatment plants, including the conversion of cesspools and septic tanks into WWTPs.

Both types have similar technology, but the TOPAS R-BASIC type does not include a control unit. The TOPAS R-BASIC technology includes an inflow tank, activation tank (bioreactor), and sludge tank, with the inflow tank connected at the bottom to the activation tank, forming a “connected vessels” system. In contrast, in the TOPAS S system, the inflow and activation tanks are watertight separated, and wastewater is pumped from the inflow tank to the activation tank. This makes the inflow tank also function as a pumping station and simultaneously serves to accumulate surge inflows.
Generally, TOPAS R-BASIC treatment plants are suitable for installations where the inflow sewage line is buried up to 0.7 m below the ground. TOPAS S are suitable for greater inflow depths, up to 1.2 m, where in other types of domestic WWTPs, it is necessary to precede with a pumping station or the treatment plant needs to be expensively concreted.
TOPAS R-BASIC treatment plants are designed only for permanently inhabited buildings, while TOPAS S treatment plants can be installed for both family homes and for cottages, i.e., recreational facilities with intermittent operation.


A  Inflow Tank
Activation Tank (Bioreactor)
Sludge Tank
Technology Box

A   Inflow Tank  – serves to capture and grind coarse impurities, to homogenize sewage, and for denitrification (removal of nitrates from wastewater).

B   Activation Tank (Bioreactor) – this is where the biological treatment of wastewater occurs by microorganisms contained in the “activated sludge”. Aeration provides the energy for this process. Further, it involves the oxidation of ammonia to nitrates and the separation of treated water from activated sludge.

C   Sludge Tank  – used for storing excess sludge as a product of biological treatment. The principle is that the better the treatment plant works, the more excess sludge is generated for storage. If the treatment plant does not have a separate sludge tank and automatic desludging of the activation tank, sludge can leak into the clean water outflow even with minor maintenance neglect.

D  Technology Box – the box is used to store the blower, electrovalves, and other electrical accessories.

Installation of the Treatment Plant

The TOPAS R-BASIC treatment plant consists of a self-supporting circular plastic tank, which is installed in an excavation so that the lid of the treatment plant is at least 100 mm above the finished ground level to prevent the ingress of surface water into the treatment plant. The treatment plant is factory-equipped with inlet and outlet pipes DN 110 mm. The bottom edge of the inlet is 0.7 m and the outlet is 0.8 m below the finished ground level. Both the outlet and the inlet are formed by the smooth end of the pipe.


A  Depth of inflow below ground level 0.7 m
B  Total height 2.4 m
C  Height of outlet above the bottom 1.4 m

Backfill and Filling of the WWTP

After installation, the treatment plant is filled with water and backfilled with sand or the original “reversed” soil. The backfill under the connecting and outlet pipes must always be made with compacted gravel sand (preferably stabilized with cement) to prevent later settling of the backfill, which could damage the stability of the pipes.


Electrical Connection

Each treatment plant is equipped with a 230V plug, connected to an acidur supply box. This plug is used for provisional connection and testing of the treatment plant with an extension cord. The connection from the property is made with a cable of at least CYKY 3J x 2.5 to the acidur electrical supply box – see wiring. If an electrician or installer with the appropriate professional qualification for the installation of electrical equipment is present during the installation, the supply cable will be connected directly to the treatment plant and the provisional connection will be discontinued. The connection in the property and the electrical connection are carried out individually and are not part of the treatment plant delivery. It is essential that the power supply to the treatment plant is protected by a current circuit breaker.

WWTP with a Tank for Treated Water (DUO)

The treatment plant can be manufactured in a single block with a tank for treated water (or possibly for storing excess sludge). The WWTP and the treated water tank with a volume of 2m³ are produced as one compact product. This achieves significant savings on transportation, earthworks, installation, assembly, and interconnection, which are completely eliminated compared to the installation of a separate WWTP and a separate tank for treated water. The treated water can be used as utility water or for garden irrigation.

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