General information – residential wastewater treatment plants

čistiarne odpadových vôd Aquatec VFL -  Sewage water treatment systems

AT6 - AT20 packaged residential wastewater treatment plants were invented to purify sewage water for detached houses. Furthermore, the purified water can either discharge into the surface or be utilized for irrigation.


In compliance with requirements of European Norm EN 12566-3, the residential wastewater treatment plant was subjected to a long-term efficiency test of purification, comprehensive tests of static resistance, water tightness, durability and the checking of dimensions of accessibility. The initial tests and internal control of the workshop proved that the conformity, the manufacturer declared, is in full compliance with the EU legislation. This way, the company was authorised to label the plant "AT to 50 PE" with the CE Mark of Conformity.

Basic description


The wastewater treatment plant consists of an all-plastic reactor with a built-in technological structure. Because of the low loaded activated sludge process with aerobic sludge stabilization, it can achieve the maximum treatment efficiency.
AT wastewater treatment plant includes a removable, lockable PE cover with stainless steel locks. The AT 
wastewater treatment plant uses a well-established system of a continuous-flow, suspended growth activated sludge process with an integrated retention chamber to handle the surge of inflowing wastewater. The treatment technology ensures the high quality of purified water, low investment and operation costs. The technology also can be found under the international name of Vertical Flow Labyrinth - VFL.
Vertical Flow Labyrinth – VFL® - Treatment process
čistiarne odpadových vôd Aquatec VFL -  Sewage water treatment systems
The technology uses a continuous-flow activated sludge process with biological nitrogen and phosphorus removal, which combines the following processes in a single tank:  mechanical pre-treatment, excess sludge collection, biological treatment using a low-loaded activated sludge process, separation of the treated water from activated sludge in the final clarification chamber, flow balancing of fluctuating inflow of wastewater in the retention chamber. The treatment process consists of several technological processes. Raw wastewater flows into the non-aerated activated sludge chamber with anaerobic and anoxic zones creating and admixture with the recirculated activated sludge, the mechanical pre-treatment of inflowing raw wastewater and the decomposition of coarse impurities, denitrification and accumulation of readily degradable organic contamination is taking place in the non-aerated activated sludge chamber, which is divided by inner partition walls to create a vertical flow labyrinth, where internal circulation is established. 
Furthermore, allowing the admixture flow gravitationally into the aerated activated sludge chamber with includes fine-bubble diffusors. In oxic conditions the biological degradation of organic contamination, nitrification and phosphorus uptake is taking place.  The activated sludge flows into the final clarification chamber, where the activated sludge is separated from the treated wastewater. The treated wastewater is discharged into a water flow, infiltrated or recycled and the separated activated sludge is recirculated by air-lifts.
A flow regulator is installed at the water level in the final clarification chamber which controls the outflow in order to maintain the water level between the normal and maximum level in the tank (integrated retention chamber).
The pressurized air is supplied by blowers for aeration of the activated sludge chamber and for recirculation via air-lift pumps. The recirculation and aeration is controlled by a microprocessor control unit which also enables the wastewater treatment plant to work in various modes depending on the loading.

1 – Anaerobic and anoxic zones with „Vertical Flow Labyrinth“

2 – Oxic chamber

3 – Final clarification chamber

4 – Integrated retention chamber

5 – Internal recirculation

6 – Recirculation of sludge

7 – Fine-bubble diffusor

8 – Flow regulator

čistiarne odpadových vôd Aquatec VFL -  Sewage water treatment systems

The technology Vertical Flow Labyrinth – VFL®, used in the biological reactor, is protected internationally by patent. The purification technology ensures the high quality of purified water, low investment and operation costs.

European Union
The AT wastewater treatment plant meet the requirements for the resistance of inflowing sewage water abruptly. Ensuring the homogeneous operation of the wastewater treatment plant in the event of abrupt outpour of high volume of water (e.g. bathtub, washing machine, etc.). The wastewater treatment plant main problem is respect to the discharge of the activated sludge upon every abrupt inflow resulting in solving this issue.

Technological parameters
The quality of purified water corresponds with the Directive No. 269/2010 requirements in the Collections of Laws according to the Government of the Slovak republic for discharging the water into the ground or on the surface.

Parameter Average value Guaranteed value
COD 35 mg/l 75 mg/l
BOD 10 mg/l 15 mg/l
SS 10 mg/l 20 mg/l
N-NH4 2 mg/l 5 mg/l
Ntot 15 mg/l 25 mg/l
Ptot 3 mg/l 7 mg/l

Technical parameters:

TYPE Tank diameter
Tank height
Inflow height
Outflow height
Manhole diameter
DN inflow/outflow
AT 6 1400 1800 1300 1150 1400 125/125
AT 8 1400 2200 1700 1500 1400 125/125
AT 10 1750 2200 1500 1250 1400 125/125
AT 12 1750 2400 1700 1500 1400 125/125
AT 15 2050 2200 1700 1500 2050* 150/150
AT 20 2050 2700 2200 2000 2050* 150/150

* according to selected solution.  

AT6, AT8 and AT10 wastewater treatment plants from Aquatec VFL company. Size and shape comparison:

AT6, AT8 and AT10 wastewater treatment plants from Aquatec VFL company. Size and shape comparison:

AT8k - 800 mm manhole, walkable

AT8k - 800 mm vstupny otvor s pochôdznym krytom


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