Sequencing Batch Reactor TOPAS S


TOPAS S, tested and certificated according to EN 12566-3, is domestic wastewater treatment plant used for effluent from family houses, cottages, hotels, pensions and restaurants (including wastewater from washing machines and dishwashers).
Wastewater treatment plants are delivered as complete products, including the lid. No additional adapters according to the depth of the inflow piping are required.
TOPAS tank is made by polypropylene which ensures the long term service life of the product.
The original technical solution of TOPAS wastewater treatment plants is protected by international patent.

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These are mainly application:

  • family houses;
  • sport centres and cottages,
  • hotels and pensions;
  • restaurants.



TOPAS S is a Sequencing Batch Reactor (SBR) plant equipped with a first chamber working as flow equalization and homogenization.
Wastewater enters in the equalization (accumulation) section and than it is pumped to the activation section (biologic reactor). Aerobic biological treatment takes place in the activation zone which is aerated during filling and reaction phase and than stopped in other phase. During the sedimentation phase sludge settles at the bottom of the tank and than clarified water is discharged with a special system (decanter). The treatment process is regulated via a control unit with a special programme. Sludge from the activation tank is automatically drawn off to a separate sludge tank which is regularly emptied.

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Small wastewater treatment TOPAS S has a variable inlet from 0.4 to 1.2 m below the ground level.

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A – Accumulation (inflow)
B – Activation
C – Settlement
D – Sludge storage (aerated)
E – Air blower
F – Treated water accumulation


The wastewater treatment plant (WWTP) ensures an automatic and continuous operation depending on the volume of inflowing wastewater.
The control unit enables a special mode to be set for treatment of non-standard wastewater (heavily or slightly polluted).
Potential defects are signalled on the control unit and can be sent via SMS or by email.
The mobile phone can be used for adjusting treatment parameters, checking the amount of treated water or operating parameters of all the system and for remote control of the plant operation
See Accessories or TOPAS GSM module.


If within the set time the control unit does not detect any inflow of wastewater, it starts the stand-by mode under which the blower operates for about only 2 hours a day, saving thus energy and keeping activated sludge alive. TOPAS S can thus guarantee the biological functioning of the biological treatment for at least three months without any wastewater inflow.


All the technological components are attached with plastic clips and can be easily removed for cleaning and maintaining during the wastewater treatment plant (WWTP) operating life.
Users do not need to handle any control fittings or valves; the control unit automatically adjusts the operation according to the measured volume of wastewater for them.
The treatment process includes an automatic control to maintain an optimal sludge concentration in the WWTP.


Treated water complies with all the requirements on discharge to groundwater and surface water; a superior model also ensures the wastewater recycling for non-potable use as watering the garden. See TOPAS S PF model in Blackwater Recycling section.
The WWTP has a treated water storage section that can be equipped with a tertiary treatment if disinfection is required (TOPAS UV lamp).
The dosing system (optional) chemically removing phosphorus operates in dependence on a volume of wastewater measured by the control unit and the required phosphorous (P) concentration request for the effluent (TOPAS dosing equipment).

  • The TOPAS S is equipped with a settling tank at the inflow and with a separate sludge tank.
  • The TOPAS S tank is self-supporting.
  • Thanks to the its tank design, the TOPAS S can be placed below the groundwater level.
  • All the technological components of the TOPAS S are included in the small wastewater treatment plant.
  • The TOPAS S is thermally insulated and suitable for all climates.


Technical Specifications

The steel-plastic tank combines profiled sheet steel and thermoplastics (only rectangle model). It uses advantages of both types of material. The tanks are manufactured by welding segments of the sandwich panel of 80 mm wide. The surface of the sandwich panel is made of thin-walled polypropylene panels and there is a profiled galvanized-steel sheet hermetically sealed in between the walls. Steel contributes to the tank strength based on the static calculation for the required load and the plastic material ensures watertightness of the structure and protection of sheet steel against corrosion. Tanks can be installed both on the terrain surface and in an excavation. Large underground tanks are installed on the concrete baseboard smaller tanks need just sand bedding and as a standard all tanks are designed without necessity to surround the tank with concrete walls. Tanks can also be installed without any structural changes below the groundwater level.

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  • tank watertightness
  • long life without corrosion
  • chemical resistance
  • structural resistance
  • thermal insulation

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Gross dimension are shown in table as follow.

rectangular shape
PE Q w l L h th P W
Name [-] [m3/d] [cm] [cm] [cm] [cm] [cm] [Watt] [kg]
TOPAS S 8 8 1.2 120 150 150 200 250 80 590
TOPAS S 10 10 1.5 120 200 200 200 250 150 590
TOPAS S 15 15 2.3 150 200 200 200 250 200 640
TOPAS S 20 20 3.0 220 200 200 200 250 200 1090
TOPAS S 30 30 4.5 230 300 300 200 250 300 1450
TOPAS S 40 40 6.0 230 400 400 200 250 300 1800
TOPAS S 50 50 7.5 230 400 400 230 270 550 1850
TOPAS S 65 65 9.8 230 500 500 230 270 1100 2000
TOPAS S 80 80 12.0 230 600 600 230 270 1100 2300

For a larger number of inhabitants implants are composed of several modules.
For more information contact the technical department.

Smaller plants are available also in circle version.

circle shape
PE Q D h th P
Name [-] [m3/d] [cm] [cm] [cm] [Watt]
TOPAS S 5 5 0.8 120 2.0 – 3.0 2.4 – 3.4 60
TOPAS S 8 8 1.2 50 2.0 – 3.0 2.4 – 3.4 100

NOTE: sizes can be changed without notice.
The letters in figures and table have the meanings set out below:

PE – population equivalent served
Q – daily flow
w – width (rectangle)
l – length (rectangle)
D – diameter (circle)
h – height
th – total height
L – Pollution load
P – power
W – weight

Design parameters

Water consumption: 150 l/PE day
Biological Oxygen Demand (BOD5): 60 g BOD5 /PE day

TOPAS S is available in two different shape type: rectangular and circulars shape.
Circular model is made only by polypropylene sheet (no sandwich panel).
Inlet flow level can different depending on the needs of the construction site from 0.7 to 1.2 below the ground level.
Note that the wastewater storage volume (accumulation A) change according to inflow pipe level.

TOPAS S is designed considering a daily water consumption of 150 l and a amount of Biological Oxygen Demand of 60 g BOD 5 per day per person equivalent (PE).

All variants of WWTP TOPAS S are equipped by the control unit with a display.


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  • PHASE 1: aeration element in activation tank, aeration element in sludge tank, raw sewage air-lift pump.
  • PHASE 2: aeration element in accumulation.
  • PHASE 3: decanter filling air-lift pump.
  • PHASE 4: desludging air-lift pump, aeration element in accumulation.
  • PHASE 5: treated water air-lift pump, aeration element in accumulation.
  • PHASE 6: (backward) desludging air-lift pump, aeration element in accumulation.

For further information and tailor made solutions, please contact technical office.



Guaranteed parameters of TOPAS S wastewater treatment plants

Medium effluent quality parameters:
  • Biochemical Oxygen Demand (BOD5): 15 mg/l
  • Suspended Solids (SS): 15 mg/l
  • Chemical Oxygen Demand (COD): 70 mg/l
  • Ammonium (N-NH4): 15 mg/l
Maximum effluent quality parameters:
  • Biochemical Oxygen Demand (BOD5): 30 mg/l
  • Suspended Solids (SS): 30 mg/l
  • Chemical Oxygen Demand (COD): 120 mg/l
  • Ammonium (N-NH4): 30 mg/l

The above mentioned values are achieved and guaranteed for wastewater treatment plants which are operated and loaded in accordance with the valid operating order and User Manual.

Small Wastewater Treatment Systems TOPAS S is EN 12566-3 certificated and CE marked according to EN regulations.