Wastewater Treatment Plants - Aquatec VFL, s.r.o.

Pre-assembled AT 75-750 wastewater treatment plants

The pre-assembled residential wastewater treatment plants of the AT 75 to AT 750 series purify sewage water from residential buildings, groups of buildings, small municipalities or parts of municipalities and from sources of wastewater, where sewage water is produced; this includes accommodation facilities, restaurants, schools, recreational facilities, production plants, industrial parks, etc. After the preliminary purification of organically contaminated wastewater, they serve as a degree of final biological treatment for meat-processing plants, slaughterhouses, dairies, cheese-dairies, wine-making plants, etc. Purified wastewater is further drained in the surface or ground water or, as the case may be, recycled to water lawns and greenery.

Basic description
Assembled wastewater treatment plants of the AT 75 to AT 750 series consist of one or several all-plastic reactors of circular top view and additional devices such as a pumping station, mechanical preliminary purification, mud sump, etc. The maximum achievable purification effect is based on the utilisation of low-loaded activation technology with aerobic sludge stabilisation. A tried and tested system of continual biological treatment of wastewater is used in the AT wastewater treatment facility with an integrated accumulation of abruptly inflowing water. This technology is protected in Slovakia by utility models UV 4324 and UV 2750 and internationally by patent No. EP1919833. Our purification technology ensures the high quality of treated water and low investment and operating costs. The technology is also known under the international name of Vertical Flow Labyrinth – VFL®.
The AT wastewater treatment facility is delivered based on a binding order, while payment and delivery conditions are subject to mutual agreement between the customer and supplier.

Purification process
It consists of a sequence of several technological processes. Wastewater being preliminarily treated mechanically flows to a non-aerated space, where nitrogen is biologically degraded and the conditions are created for the partial biological degradation of phosphorus. The non-aerated activation space is divided into several inner partition walls creating a vertical flow labyrinth, where internal circulation has been established.
Further, wastewater flows gravitationally into an aerated space with low-loaded activation, where, under the presence of oxygen, the biological degradation of organic contamination and nitrification of ammonia nitrogen occur. The air is supplied to the aeration system by blowers with a side duct (high-pressure fans) that are placed outside the biological reactor. The pressurised air is blown into the aerated space through fine-bubble aeration elements. The pressurised air supplied through the blowers can be regulated using a time switch or frequency converter, which the wastewater treatment facility may use in various modes depending on the loading.
Another degree of treatment is separation, whereby the treated water is separated from the activated sludge, while the purified water is discharged to a water flow, infiltration or recycled and the set-off activated sludge is returned to the system by re-pumping from the bottom of the feeding space to the non-aerated space or, as the case may be, aerated space. The streamflow regulator, which is found in the feeding space, allows the use of the built-in retention space in the wastewater treatment facility in the event of abruptly inflowing wastewater, thus preventing the facility from being overloaded. This creates the conditions for discharging wastewater via leakage into the ground water and reclaiming biologically purified wastewater, as the discharged water does not clog the pores of the filtration layer of the bedrock or filtration facility. Excessive sludge is thickened and stored in a mud sump. Sludge production is distinctly lower compared to other systems.

Technological parameters
The quality of the purified water corresponds to the requirements of Directive No. 269/2010 of the Collection of Laws of the Government of the Slovak Republic on discharges into surface and ground water. Guaranteed and commonly achievable parameters on

Technical parameters:

Installation of the wastewater treatment facility
The reactor and mud sump of AT 75 - 750 wastewater treatment plants are placed as partially sunken tanks into the excavation on a common concrete base slab approximately 30 cm thick, so that the upper edge of the tank protrudes about 100 cm above the ground. The tanks may be placed at a maximum depth of 2 m. If necessary and as required by the contract documents, the tanks must be concreted up to the height specified by the contract documents. Before actual backfilling or concreting, the wastewater treatment facility tanks must be filled with water up to the edge of the discharge piping. A detailed guide for installing the wastewater treatment facility is shown in the operating instructions.