Corn Fermentation Alcohol Wastewater Treatment Technology
With the increasing scarcity of oil resources, the price of oil has risen sharply. At the same time, the promotion of environmentally friendly and clean new energy – fuel ethanol is deeply favored by scientists. In the future, fuel ethanol will replace some gasoline. energy breakthrough.
At this stage, the raw material used for ethanol extraction in my country is corn. Because corn is rich in starch, it is very easy to ferment, and the price of ethanol produced is relatively moderate. However, since the wastewater from corn fermented to extract ethanol is seriously polluting, if it is rashly discharged without certain treatment, it will cause serious pollution to the surrounding environment.
Separation technology of corn alcohol mash
Under normal circumstances, the production of 1 ton of ethanol requires 3 tons of corn. According to the different fermentation and mature wine content, the amount of alcohol mash produced per 1 ton of ethanol is about 9-12m3. This alcohol mash is composed of dissolved solids, suspended solids and colloids, and has certain corrosiveness and viscosity, so this mash needs to undergo a series of technical treatments to achieve safe discharge.
Centrifugal separation technology
General enterprises mainly use centrifugal separation technology when separating solids in alcohol mash, and this centrifugal separation technology generally uses decanter centrifuges, which are the most advanced at present at home and abroad. A kind of equipment, represented by a horizontal spiral decanter centrifuge, which does not need to filter the medium, has good wear protection, and has the advantages of low energy consumption. It is widely used in solid separation.
This technology basically dries all the solids in the alcoholic mash together. For example, the clear liquid produced after centrifugal separation needs to be mixed with the solids in the centrifugal separation after the syrup formed by evaporation and concentration is mixed and healed, and then passed through After a series of treatments such as drying and packaging, it becomes the feed used in animal husbandry.
This is the so-called waste utilization. Using the DDGS process can turn the waste into feed for use, and the high COD wastewater such as evaporative condensate generated during the evaporation and concentration process of the clear liquid must be treated by a wastewater treatment device. This part of the process belongs to the treatment of alcohol wastewater in China. .
Corn alcohol wastewater treatment technology
Using corn fermentation to produce alcohol, the industrial wastewater produced has a certain degree of acidity, and the content of BOD and COD is relatively high. If aerobic biological treatment technology is directly used, a large amount of cost will be incurred. The combination of anaerobic and aerobic treatment technology can not only save a certain cost, but also greatly improve the success rate.
Anaerobic biological treatment technology
Anaerobic biological treatment technologies usually include anaerobic granular sludge expanded bed (ECSB), upflow anaerobic sludge bed (UASB), anaerobic baffled reactor (ABR), multistage internal circulation anaerobic reactor ( Among them, the Upflow Anaerobic Sludge Bed Reactor (UASB) is the most widely used.
This kind of reactor consists of three parts: sludge reaction zone, gas-liquid-solid three-phase separator and gas chamber. There is a large amount of anaerobic sludge in the bottom reaction zone of the reactor, which has good sedimentation and coagulation functions. The corn alcohol wastewater flows into the anaerobic sludge bed and is fully mixed with the sludge in the sludge layer. At this time, the microorganisms in the sludge will fully decompose the organic matter in the wastewater, and then convert it into biogas. Biogas is continuously generated in the form of tiny bubbles, and continuously merged to form larger bubbles.
In the upper part of the sludge bed, the sludge with low sludge concentration is put into the three-phase separator together with water through the biogas, and then passes through the gas chamber, where the biogas is collected together and exported through the conduit, and the sludge and water form The mixed liquid will pass through the three-phase separator for precipitation. At this time, the particles of the sludge will become larger, and will be precipitated under the action of gravity, and then enter the anaerobic reaction zone, so that a large amount of sludge will be formed in the reaction zone. The water after the sludge overflows from the upper part of the overflow weir in the sedimentation area to discharge the sludge bed.
This kind of reactor has a high volume load rate, and the equipment is simple to operate, and it does not need to be filled with fillers, nor does it need to set up a mechanical stirring device in the reaction zone. Usually, it has a wide range of applications in China.
Aerobic biological treatment technology
Traditional aerobic biological treatment technologies include sequential batch Martian sludge process (SBR), cycle activated sludge process (CASS) and intermittent cycle delayed aeration activated sludge process (ICEAS), among which ICEAS The process is the most commonly used. This process is an improved process based on the sequential batch activated sludge process (SBR). A partition wall is added to the reaction tank of SBR, and the reaction tank is divided into a pre-reaction zone and a main reaction zone. The reaction zone can be used to regulate water flow, while the main reaction zone is used for aeration and sedimentation.
ICEAS is a process of continuous water inflow. In the reaction stage, as well as in the precipitation and decanting stages, water is inflow. After the sewage enters the pre-reaction zone, it enters the main reaction tank through the connecting port at the bottom of the partition wall. Indirect aeration and precipitation decanting are carried out in the middle, making it a SBR reaction tank with continuous water inlet and indirect effluent, which will not affect the quality of the effluent. It has the advantages of strong adaptability, less sludge generation and simple operation.
Due to the high concentration of COD and BOD in corn alcohol fermentation wastewater and good biodegradability, many alcohol enterprises generally use anaerobic and aerobic biological treatment technologies for treatment, the purpose is to be able to recycle wastewater. Pay more attention to environmental protection and energy saving, and better protect our natural environment.