Wastewater Treatment of Distiller’s Grains(2)

The distillery directly sells / sends the distiller’s grains wastewater produced in the production process directly to the local pig farm, fish farm, shrimp farm, or earthworm farm as the direct feeding fertilizer is the simplest, most direct and economical treatment method. As a result, distiller’s grains wastewater can be digested on the spot without destroying the local ecological environment. It is also a very economical feed source for local third parties such as pig farms and fish farmers and shrimp farmers. Winery can also do not need to invest more cost to consider sewage discharge and a series of environmental issues. This treatment is the mainstream treatment of small and medium-sized distilleries for many years. With the outbreak of African swine fever in our country, the number of pigs in pig farms With the waterfall-style collapse, the demand for distillers’ grains in pig farms, one of the main places to go, has also plummeted, with the result that distilleries in many places have chosen to store the excess grains temporarily after simple solid-liquid separation, waiting for the swine fever epidemic to pass before shipping them to pig farms. But with the outbreak of swine fever, regulatory requirements for the source and quality of feed have increased, and swine fever has continued longer than expected, making it impossible for more and more distilleries to hoard distillers. Other treatments must be considered.

If distiller’s grains can not be sold to local third parties for local digestion, the simplest and most traditional method is biochemical treatment. The so-called biochemical treatment is that after the solid-liquid separation of distiller’s grains wastewater by centrifuge, the wastewater is discharged into a biochemical tank. After a series of steps, such as anaerobic, aerobic, sludge reduction and so on, the BOD and COD content in the wastewater are reduced to meet the national discharge standard. The solid slag (distiller’s grains) separated by centrifuge is dried and treated as solid waste. Using this way to deal with is actually helpless. This treatment is direct and simple, but the time, site requirements, and distiller’s grains are uncertain Processing methods can not become mainstream for a long time. Different distiller’s grains wastewater, in different climates, the time required to treat a batch of distiller’s grains wastewater varies from 10 to 20 days, which requires high land cost and time cost for enterprises. Because it is treated by biochemical method, in different environments, the effect of treatment will not remain the same, so enterprises are required to have strict requirements for the closing of the discharge of sewage. Put an end to the discharge of substandard sewage to the national sewage station into the river to cause second pollution. This is also a drawback and uncontrollable aspect of this treatment.

At present, there are some small wineries in China to “upgrade” the biochemical treatment. After simple solid-liquid separation of distiller’s grains wastewater by centrifuge, the effective substances in the wastewater were enzymatically hydrolyzed (released) by adding bacteria microorganism, and then collected and sold as animal feed nutrition additives by concentration, drying and other treatment methods. Although this method still needs to discharge the remaining sewage after biochemical treatment, it can bring certain economic effect to the enterprise after all. In the long run, this method is more favored by the enterprise. But also because of the complexity of enzymatic hydrolysis, as well as the singularity of bacteria, is doomed to use this “upgraded” biochemical treatment method can not maximize the value of distiller’s grains wastewater, and still need to biochemical treatment of the remaining wastewater, can not achieve 0 discharge. Whether from the management of enterprises or the monitoring of relevant state departments have higher requirements.

The above is small for everyone to bring the current domestic distiller’s grains wastewater treatment status. I hope it will help you. In the next issue, we will explain in detail the treatment methods of distiller’s grains wastewater in foreign countries, and will also share with you the treatment methods of distiller’s grains wastewater which can be discharged 0 in China at present.

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