What is vegetable oil wastewater? It generally refers to cleaning wastewater, cooking wastewater, and oily and acidic wastewater. Vegetable oil wastewater has a high content of organic matter and emulsified oil, while the content of heavy metals and toxic substances is relatively low.

So how to treat vegetable oil wastewater? In this article, we will give a brief introduction together with manufacturers of Online Water Quality Monitoring Instruments. The pretreatment is mainly carried out through the following steps:

1.Oil Separation

First, oil isolation is performed. Oil separation tanks can be horizontal flow, inclined plate, or parallel plate types. In the oil separation process, suspended solids and water have different specific gravities, and the oil separation tank can remove oil particles down to a certain minimum size. Oil-water separation is achieved by natural separation based on the specific gravity of suspended solids.

The higher the oil content and the larger the oil particle size in the wastewater, the better the oil separation effect.

2.Air Flotation

Next is air flotation. Different from oil separation, air flotation attaches microbubbles to oil contaminants, forcing the suspended pollutants to float upward to achieve oil-water separation.

There are three main types of air flotation: electrolytic air flotation, dissolved air flotation, and mechanical shear air flotation.

3.Coagulation and Demulsification

This step mainly involves coagulation and demulsification, which applies the salting-out method. Electrolytes such as magnesium and sodium salts are added to the oily wastewater to compress the electric double layer on the surface of oil droplets, thus achieving the pretreatment effect.

However, if vegetable oil wastewater is pretreated only by the salting-out method, a large amount of salting-out agent is required. In addition, the aggregation and sedimentation separation of pollutants take a long time, and the process facilities occupy a large area, making it unsuitable for many scenarios.

4.Activated Sludge Process

Under aerobic conditions, air is introduced into the oily wastewater to be pretreated, and a large number of microorganisms are cultivated. These microorganisms grow cyclically in the wastewater, and the dissolved oxygen concentration can be increased by appropriate methods.

Such aerobic microorganisms have strong adsorption capacity. During their growth, they can degrade oil droplets and suspended solids in the wastewater and convert them into organic components for their own growth, thus realizing the pretreatment of oily wastewater.

Kind Reminder

The proper application of wastewater pretreatment technologies has an important impact on online water quality monitoring. The accuracy of monitoring results and water treatment methods will be affected accordingly.

Therefore, during water quality testing, operators should conduct a detailed analysis of the wastewater, select efficient pretreatment technologies, accumulate experience and professional knowledge, and pay attention to environmental protection.