Sewage treatment plants BioKOS

Mechanical treatment is designed to trap debris, sand, and other contaminants. Mechanical treatment typically consists of two sections: a large contaminant trap (garbage trap) and a sand trap. The large contaminant trap can be a manually cleaned screen, a self-cleaning UFS screen, a mechanized rake screen, or a mechanized trash trap. The following types of sand traps can be used as sand traps: a horizontal aerated sand trap or a combined sand and trash trap (Combi). The choice of trash trap and sand trap depends on the treatment facility's capacity, the amount of contaminants, and technical requirements.

The equalizing tank is designed to equalize wastewater flow rates and composition. Water enters the equalizing tank at varying hourly rates, depending on the population's water usage schedule. Water leaves the equalizing tank at a constant flow rate equal to the average hourly flow rate. The presence of the equalizing tank helps ensure maximum stability in pumping water to the biological treatment system, thereby improving the quality of biological treatment.

After the equalizer, the wastewater enters the anaerobic section, where phosphorus is removed biologically using activated sludge from the secondary clarifier. In the anaerobic section, the wastewater and sludge are constantly mixed to create optimal conditions for the dephosphorus removal process.

After the nitrifier, the water enters the secondary clarifier, where the shape of the clarifier reverses the flow direction. The water first moves downward and then upward, separating and settling the activated sludge at the bottom of the clarifier. The settled sludge is pumped into the denitrifier, and the clarified water is sent for further treatment.

From the denitrifier, the wastewater mixture passes into the nitrifier, where it is purified with activated sludge. Air is supplied to this section through aerators to support the aerobic bacteria. A constant-flow recirculation pump is installed at the tail of the nitrifier.

From the denitrifier, the wastewater mixture passes into the nitrifier, where it is purified with activated sludge. Air is supplied to this section through aerators to support the aerobic bacteria. A constant-flow recirculation pump is installed at the tail of the nitrifier.

BioKOS treatment facilities use a drum microfilter for post-treatment. Mesh drum filters operate as follows: treated water flows continuously through an inlet pipe into the drum, is filtered through mesh filter elements, and enters the unit's chamber, from where it flows through a drain into a channel that discharges purified water. The mesh filter drum is not completely submerged in water—its upper portion is above the water (approximately 0.15 times its diameter). When the filter element is in the upper position, contaminants are washed by jets of water from a backwash device into bins located inside the drum, from where they flow into a drain pipe and are discharged into the sewer. The mesh drums are periodically backwashed depending on the degree of contamination of the filter mesh.

BioKOS facilities incorporate two types of disinfection for biologically treated water: UV disinfection and sodium hypochlorite disinfection. Following final treatment, purified water passes through a unit with UV disinfection lamps, where bacteria are destroyed by saturating the water with UV light. For deeper disinfection, the water after UV purification is fed into a contact tank, where a hypochlorite solution is dosed. Each type of disinfection covers the entire disinfection requirement, so there is no need to use both methods simultaneously. During operation, one of these disinfection options can be selected, or, if increased disinfection requirements are required or there is a risk of failure of one of the disinfection methods, both methods can be used.

A sludge stabilizer is designed to store and stabilize excess sludge. It consists of a tank with aerators installed inside. If necessary, the sludge stored in the stabilizer can be used to restart the treatment plant without the need to transport sludge from another treatment plant. Stabilized sludge is more resilient to dewatering processes, making the stabilizer an essential step in subsequent sludge dewatering.

A sludge dewaterer is designed to separate water from stabilized sludge. Two sludge dewatering options are available: bag dewaterers and screw dewaterers. The choice of dewatering option depends on the treatment plant's capacity.