This option is necessary in a place with a single-pipe system. The equipment – an overflow (OF) – is located in the preliminary shaft ahead of the inflow of the WW into the pumping station. The OF is a certified finished product allowing a WW volume of Qmax. to be conveyed into the WWTP and the WW volume to be relieved into the by-pass, thinned in a proportion required by legislation, which will flow to the recipient either through the rain tank or directly. The filling of the rain tank is enabled by a motor-operated slide, which opens and closes the entry into the rain tank from the by-pass. In the case of torrential rain, the slide opens from the by-pass into the rainwater retention tank. In normal operation, the slide is in the open position into the WWTP, closed into the by-pass. In the case of torrential rain, the inflow into the treatment plant is closed and the inflow into the by-pass or the rainwater retention tank opens simultaneously. The control may be remote or automatic via a rain sensor.
The basic version envisages the transport of aerobically stabilised sludge, gravitationally densified to 20-25g/l using a faecal suction truck to the nearest big treatment plant for further processing. If it is not possible, we offer to add equipment for sludge dewatering by pressing using a screw press or a screen belt press. The pressed sludge cake contains 20% of dry matter and its further use must be in accordance with legislation on the handling of sewage sludge. It can be used as a garden or field fertiliser. Water from the press – the filtrate – flows into the collecting tank and returns to the accumulation section of the process tank via a pump. The equipment is located in a separate container together with a device for inserting and dosing a flocculant into the sludge before the pressing process. Composted sludge can be used as a quality garden or field fertiliser.
The quality of the cleaned WW and its wholesomeness allow its reuse for flushing the technological equipment for WW pre-treatment, sludge dewatering equipment, in sanitary facilities for flushing the toilet, the maintenance of green areas in the WWTP area etc. Further use of the cleaned WW is possible while using it as service water for agriculture, e.g. for irrigation during the growing season and other purposes. The equipment consists of a pressure water station connected to a distribution pipeline to places of its direct consumption. Cleaned WW not used for the above purposes flows into the recipient, to wetlands etc.
This option is suitable for higher outputs and high pollution of wastewater by phosphate compounds and wherever required by environmental authorities. The treatment is done using the simultaneous coagulation technology. Phosphor is normally coagulated using ferric or ferric-aluminium coagulants, dosed into the denitrification section. The equipment consists of a separate solution reservoir and a dosing pump, which doses the chemical into the denitrification tank in a set ratio.
It is possible to use solar energy on the WWTP by installing photovoltaic cells. Energy gained from them is used for lighting, as a backup power supply for the control system, or to drive part of the technological equipment. The solar system contributes to the reduction of electricity running costs.
Operating facilities are used to provide utilities, operating media and the overall operation of the treatment process in the basic configuration. These operating facilities are designed to be located in transport 20’ containers with dimensions 6 x 2.4 x 2.52m and are delivered with the following equipment:
The equipment in the container provides compressed air necessary for the aeration in the nitrification section, for the bioreactor and airlift pump modules. 3 pcs of Roots blowers are located here, 1 pc for nitrification, 1 pc for the bioreactor module and one backup blower with an automatic start for one or the other branch. Furthermore, distribution pipelines, a set of fittings and sensors. The operation is controlled from a central control room located in K3. The blower output is controlled using frequency converters and in the nitrification also based on oxide probe data.
The container contains a cleaned water balancing tank, reversing pumps for sucking off water from the bioreactor into the balancing tank. They also provide the flushing of membranes during reverse operation. The output of the pumps is controlled using frequency converters based on pressure and flow sensors. If the set membrane resistance is exceeded, they automatically switch the reverse operation to the back-flushing. If necessary, a container with the Fe-coagulant for phosphor coagulation can also be found here. An automatic water station is also connected to the balancing tank. This automatic water station provides pressurised water for the rotary screen, a sludge dewatering line and other use of cleaned water for utility purposes. Furthermore, chemical tanks can be found here, which are placed in safety tubs, as well as dosing pumps of chemicals, which inject a dose of a chemical (a sodium hypochlorite or citric acid solution) right at the entry of the back-flushing water into the bioreactor module at selected cycles during the membrane back-flushing.
Here is the room of the central electric switchgear and control system for the automatic control of the technological process of the WW treatment, the control of external lighting, heating, security cameras etc., with a direct connection to the internet network. Another part houses a sanitary facility with a toilet, shower and a changing room for occasional operators, also a laboratory with basic equipment for taking samples and performing necessary analyses of the WW and sludge.