Wastewater treatment plants acc. to the MBBR Technology

The SEMOCON© wastewater treatment plants are fully or partly containerized biological treatment systems operating in continous flow by applying a combination of the activated sludge with the fixed film process (Moving Bed Biofilm Reactor). Depending on the plant size, one container includes one or more functional steps of the treatment process. Generally, biological treatment and the final clarifier are integrated in one container. The containers are devided – similar to on site build concrete tanks – by dividing walls in functional compartments.

Plant inflow: Inflow to the admission / bypass manhole can be by gravity or by pumping. The knife gate valve located in this manhole allows the isolation of the following functional blocks in case of major maintenance works.

Mechanical pretreatment: The mechanical pretreatment stage consists of an automatic screen which provides solid waste removal from waste water before it reaches the buffering and mixing tank. Sand or grease trap can be included on customers request.

Buffering, mixing and denitrification tank: The pretreated wastewater is stored in this tank. A submersible mixer homogenizes the flows - inflow, internal recirculation and 
sludge return. The buffering and mixing tank has also the function of a denitrification basin. For the wastewater treatment plants type SEMOCON© we do not use primary treatment tanks. 
Thus we obtain an optimal C/N relation ideal for denitrification in anoxic conditions. In addition, construction costs and the required handling when using a primary sedimentation tank are reduced. A further advantage is the flexibility of the denitrification volume which can be increased or reduced, allowing adaptation of denitrification.

Biological stage and secondary clarifier: Wastewater is pumped from the buffering tank to the aerated zone of the containerized WWTP. The nitrification stage is divided into two aerated areas, each containing a special carrier medium. The filling of the compartments is about 1/3 and 2/3. This treatment step provides reduction of the carbon-based compounds and ammonium oxidation. For the reduction of phosphorus a liquid chemical precipitant is dosed in the second aeration chamber (optional). The level of dissolved oxygen is measured by means of probes and the positive displacement blower is operated accordingly. The quantity of suspended solids is also monitored, the probe commands the excess sludge discharge solenoid valve. After leaving the nitrification step water is passed through a lamella clarifier which provides perfect separation of the activated sludge stage the clarified water. Some of the activated sludge is recycled, some is discharged as excess sludge.

Control room: All equipments requiring additonal protection are mounted in a separate control room. Control cabinet, precipitant dosing unit, polyelectrolyte preparation and sludge dewatering unit, UV disinfection unit (Hypochlorite disinfection on demand), flow metering. The blower can be also located in the control room or alternatively outside, directly near the packaged WWTP.

Excess sludge treatment: Excess sludge evacuated from the lamella clarifier is stored in an underground tank. Herefrom it is pumped to the dewatering facility. Several alternatives for sludge dewatering are available depending on the size of the treatment plant. From dehydration container, to bag filter systems or belt filter press.

Internal Recirculation: Return of activated sludge and internal recirculation is realized without pumping. By opening of electrical valves internal hydraulic circuits are activated. The internal circuits are with constant flow and directly related to the wastewater flow. No recirculation pumps are used, hence power consumption 
of the WWTP is significantly reduced. By activating an additional electrical valve (controlled by the suspended solids probe, alternatively by timer) excess sludge is sent periodically to the sludge storage tank. 


Without pretreatment tank, hence investment and operation cost are reduced

 Flexible denitrification volume

2-stage biological treatment step

High performance carrier media (protected area >600m2/m3)

Level sensor in the final clarifier for ECO-mode operation in periods without inflow (reduced aeration, recirculation switched off)

Without recirculation pumps, electricity consumption is thus substantially reduced


Containerized plants for 500, 750, 1000 PE with MBBR technology (optional SBR). Standard packaged plants include in one container a two-stage biological treatment with nitrification and the final clarifier. Other configurations e.g. with denitrification compartment are also available. Larger treatment plants are realized by parallel line-up of several standard packages. 

Model*CapacityPopulationTank dimensions
SEMOCON© 50075 m3/d500 PE6.0m x 2.4m x 3.0m
SEMOCON© 750115 m3/d750 PE9.0m x 2.4m x 3.0m
SEMOCON© 1000150 m3/d1000 PE12.0m x 2.4m x 3.0m


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