Biological drain cleaning
The deep biological treatment station is a local wastewater treatment plant for domestic drain cleaning. Stations of different manufacturers can differ constructively, but the principle of operation is always the same – aerobic, with constant access of oxygen, decomposition of incoming wastewaters with the help of “active silt”. Active silt is an active biomass that accumulates during the operation of the station.
The wastes entering the station are averaged over the composition, aerated and, passing alternately through a row of tanks. They are then cleaned by 95-98%. After that, they are removed from the station either by gravity (for example, into a storage or resorption well) or by a pump (into the drainage Ditch, absorbing area, reservoir of fishery value, etc.). The plant’s capacity is determined by the calculation of water consumption of 200 liters (52.8 gals) per person per day. A station designed for 5 permanent residents should have a capacity of 1 cubic meter. Meter per day.
From the existing systems of autonomous sewerage, the stations of deep biological purification have the highest degree of wastewater treatment (up to 98%) and constructive diversity (selected depending on the depth of the sewage pipe, can be completed with a post-treatment filter and ultraviolet disinfectant)
The disadvantages of such equipment can be attributed to their relatively high cost and energy compatibility. Advantages come from the efficiency, the absence of the need to periodically call the sewage machine, and, as a consequence, greater variability in the placement on the site (even indoor installation is possible) and on the tapping of purified water.
If drain cleaning does not enter the station, it continues to operate in an autonomous mode of constant water circulation. A water level sensor is installed in the receiving chamber. At the moment when the airlift pumped water into the aeration tank to the lower level, the sensor sends a signal to the control unit and the solenoid valve. The valve, triggering, directs the flow of air from the compressor to the reverse phase loop. Aeration in the aeration tank is turned off, mixing stops and all active sludge settles to the bottom – the process of denitrification begins.
At a certain distance from the bottom, the recirculation pump starts to pump out excess silt from the aerotank to the stabilizer of the activated sludge. If a mixture of activated sludge and water enters the stabilizer, some silt precipitates in the stabilizer, and the other part, together with water, returns to the receiving chamber. The water level in the receiving chamber begins to rise to the level of the sensor triggering and the transfer of the station back to the direct phase. The aeration (nitrification process) is resumed in the aeration tank, and the recirculation pump stops pumping the active sludge. In this mode of automatic switching, the station will operate until the sewage water enters it.
The diversion of purified water from the plant can be realized according to various schemes. The most common of these are Diversion of purified water by gravity into a resorption well (realized in well permeable soils with low watercut level). Diversion of treated water is done by means of a drainage pump into the reservoir, a drainage ditch, an absorbent pad. Sewage treatment facilities, for example, are used at car washes, gas stations, industrial plants, or construction sites. If the purification system is designed to purify the water from oil products, then pressure flotation is used in combination with fine filters.