There are five typical processes for sewage treatment:
(1) Intermittent activated sludge method (SBR)
Intermittent activated sludge method, also known as sequencing batch activated sludge method (Sequencing Batch Reactor-SBR), which consists of one or more SBR tanks, and when it is in operation, the wastewater enters the tanks by batches and undergoes five independent phases in sequence. It consists of one or more SBR tanks, in which wastewater enters the tanks in batches and undergoes five separate stages in sequence, i.e., water intake, reaction, sedimentation, drainage and idling. Water intake and drainage with water level control, reaction and precipitation with time control, the time of an operating cycle according to the load and water requirements vary, generally 4 ~ 12h, of which the reaction accounted for 40% of the effective pool volume for the cycle of water intake and the volume of sludge volume and the required.
Faster than the continuous flow method of reaction speed, high processing efficiency, the ability to withstand the impact of the load is strong; due to the high concentration of the substrate, the concentration gradient is also large, alternating anoxic, aerobic state, can inhibit the excessive propagation of specialized aerobic bacteria, is conducive to the biological denitrification and removal of phosphorus, but also due to the short age of the mud, the filamentous bacteria are unlikely to become the dominant, so the sludge is not easy to expand; compared to the continuous flow method, the SBR method is a short process, the device structure is simple, when the water volume and the volume of water required. The structure of the device is simple, when the amount of water is small, only an intermittent reactor, no need to set up specialized sedimentation tanks and adjustment tanks, no need for sludge reflux, low operating costs.
(2) Adsorption regeneration (contact stabilization) method
This way to make full use of the initial removal capacity of activated sludge, in a relatively short period of time (10 ~ 40min), through the adsorption to remove the wastewater in the suspended and colloidal organic matter, and then through the liquid-solid separation, the wastewater that is to obtain the purification of the BOD5 can be removed by about 85% to 90%. Adsorption of saturated activated sludge, part of the need to return to the flow, introduced into the regeneration tank to further oxidative decomposition, to restore its activity; the other part of the remaining sludge without oxidative decomposition that is discharged into the sludge treatment system.
Separately in two pools (adsorption pool and regeneration of his) or in two sections of the same pool. It adapts to the load impact of the ability to be strong, but also eliminates the initial sedimentation tank. The main advantage is that it can greatly save infrastructure investment, most suitable for dealing with wastewater containing more suspended and colloidal substances, such as tannery wastewater, coking wastewater, etc., the process is flexible. However, due to the short adsorption time, the treatment efficiency is not as high as the traditional method.
(3) oxidation ditch
Oxidation ditch is a special type of delayed aeration method, it's like a runway plane, trench set two aeration brush (disk), but also with a surface aerator, jets, or lifting tube aeration device. Aeration equipment work, promote the rapid flow of ditch liquid, realize the role of oxygen supply and mixing.
Compared with the ordinary aeration method, oxidation ditch has the advantages of provincial capital investment, easy maintenance management, stable treatment effect, good quality of effluent water, less sludge production, and better de-N, P role, adapt to the load impact capacity and so on.
(4) Continuous feed cycle cycle delayed aeration activated sludge method (ICEAS)
ICEAS reactor is equipped with a pre-reaction area in the front (accounting for 10% of the pool volume). The reactor consists of a pre-reaction area and a main reaction area, and realizes continuous water intake and intermittent drainage. Pre-reaction zone is generally in anaerobic and anoxic state, where organic matter is adsorbed by activated sludge, which also has a biological selection effect to inhibit the growth of filamentous bacteria and prevent sludge expansion. The adsorbed organic matter is oxidized and decomposed by activated sludge in the main reaction area.
Reaction of continuous water intake, to solve the incoming water and intermittent water intake does not match the contradiction. However, this process has poor sedimentation effect, deterioration of purification effect, easy sludge expansion, low sludge load, long reaction time, increased equipment volume, and larger investment.
(5) biological nitrogen and phosphorus removal process (A/A/O)
The sewage first into the anaerobic tank and reflux sludge mixing, in the role of parthenogenetic anaerobic fermentation bacteria, wastewater is easy to biodegradation of macromolecules of organic matter converted to polyphosphorus bacteria can be absorbed by the small molecules of organic matter (eg, VFA), and in the form of PHB stored in the body, and the energy required from the decomposition of polyphosphorus chain. Subsequently, the wastewater into the anoxic zone, denitrifying bacteria use the organic substrate in the wastewater to denitrify the NO3- brought in with the reflux mixture. When the wastewater enters the aerobic tank, the concentration of organic matter in the wastewater is low, and the polyphosphorus bacteria mainly obtain energy through the decomposition of PHB in the body for bacterial proliferation, while the dissolved phosphorus in the surrounding environment is absorbed into the body and stored as polyphosphorus chains, which is subsequently discharged from the system in the form of residual sludge. The lower concentration of organic matter in the aerobic zone of the system is favorable for the growth of autotrophic nitrifying bacteria in this zone.
The following equipment is required for wastewater treatment:
1 Grate cleaner?
2 Grit water separator?
3 A sedimentation tank scraper?
4Single arm peripheral drive amplitude flow scraper?
5 A sedimentation tank sludge pump?
6Aeration machine?
7Sludge return pump
8The second sedimentation tank scraper?
9Belt filter press?
10Roots blower
11Residual sludge pump?
12 Filter belt flushing pump
13 Sludge transfer pump
14 Dosing metering pump
15 Air compressor (mobile air compressor )
16 Chlorine dioxide disinfector