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

AT 75-750 container wastewater treatment plants

Container 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 the sources of wastewater, where sewage water is produced; this includes accommodation facilities, restaurants, schools, recreational facilities, production plants, industrial parks etc. After 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
The container wastewater treatment plants of the AT 75 up to AT 750 series consist of one or several purification lines and additional devices connected in parallel (mechanical preliminary clarification, pumping station, etc.). A purification line consists of three all-plastic reactors of tetragonal top view: an anoxic reactor, an oxic reactor and mud sump. The maximum achievable purification effect is based on the utilisation of low-load activation technology with aerobic sludge stabilisation. The AT wastewater treatment facility uses a tried and tested system of continual biological purification of wastewater 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 the patent No. EP1919833. Our purification technology ensures the high quality of treated water as well as 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.
Wastewater flows into a non-aerated space, where nitrogen is biologically degraded and the conditions are created for the partial biological degradation of phosphorus. The mechanical preliminary purification of inflowing wastewater and the decomposition of solid contamination also occurs here. The non-aerated activation space is divided into several inner partition walls creating a vertical flow labyrinth where internal circulation is established.
Further, wastewater flows gravitationally into the low-loaded activation oxic reactor, where, under the presence of oxygen, the biological degradation of organic contamination and the 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 loading.
The purified water is separated from activated sludge in the separation part of the oxic reactor, while the purified water is drained to the water flow, infiltration or it is recycled and the set-off activated sludge is returned to the system by re-pumping from the bottom of the feeding space to the anoxic or oxic space, as the case may be. The streamflow regulator, which can be 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. As a result, conditions are created 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 the discharge from the wastewater treatment facility:

Technical parameters:

Installing the wastewater treatment facility
The purification lines of the AT 75 - 750 container wastewater treatment plants are placed as fully sunk tanks into an excavation on a common concrete base slab approximately 30 cm thick, so that the upper edge of the tank protrudes about 10 cm above the ground. The tanks may not be placed deeper than 2.8 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 to placing the wastewater treatment facility is shown in the operating instructions.