BioTank Overview

single above ground advanced treatment wastewater plant
The BioTank is at the heart of the Aqua Tech System

The BioTank uses floating and fixed film processes in which microorganisms attach themselves to a  highly permeable media that is submerged in the wastewater. This allows for the absorption of organic and inorganic matter into the slime layer where treatment is realized. Designed properly, this filter is self-purging.


Hydraulic dosing and secondary sludge airlift pump systems are set at pre-determined rates to minimize maintenance and enhance treatment. The self-purging biological filter is designed by Aqua Tech Systems to accommodate influent characteristics and achieve effluent requirements. Oxygen is introduced to the system via an oil-less compressor and membrane aeration equipment.

Wastewater is pumped from the influent pump chamber to mechanical equipment or directly into the first baffled compartment of the BioTank. Alternatively, primarily settled
or prescreened wastewater is pumped from an equalization basin to the BioTank. Wastewater flows by gravity through each treatment compartment of the BioTank and effluent is discharged over a weir.


As flow enters each aerobic compartment dissolved oxygen is transferred to the wastewater via compressor and membrane aeration module. Each compartment has an independent and fully adjustable air regulation valve. In the aerobic modules the
compressor acts as a mixer to enhance treatment and prevent the short-circuiting of wastewater through the plant.

In the BioTank, the organic material in the wastewater is reduced by a population of microorganisms that attach to the filter media and form a biological slime layer. In the outer portion of the slime layer treatment is accomplished by aerobic microorganisms. As the microorganisms multiply the biological film thickens and diffused oxygen is consumed before penetrating the full depth of the slime layer. Consequently the film develops aerobic, anoxic and anaerobic zones.

Absent oxygen and a sufficient external organic source for all cell carbon the microorganisms near the media surface lose their ability to cling to the media. The wastewater flowing over the media washes the slime layer off the media and a new slime layer begins to form. The process of losing the slime layer is called “sloughing” and it is primarily a function of organic and hydraulic loading on the filter. This natural process allows a properly designed media bed to be self-purging and maintenance free.

Any excess sloughed biomass is transferred with the wastewater flow to the final clarifier as sludge. These secondary sludges are periodically pumped back to the primary tank or sludge holding tank for eventual removal or further treatment.

The BioTank treatment plants may also be supplied with bar racks or screens, grit chambers, flow meters, chemical dosing equipment, UV disinfection modules and sludge dewatering systems.

To put the BioTank to work for you, click the button below to schedule a consult.

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