The application of walnut shell abrasive in the treatment of high-concentration gasoline and diesel ballast sewage

The harm of oily wastewater to society and the environment

  There are many types of oily wastewater, and the sources are also very wide. In petroleum, chemical, steel manufacturing, coking, gas generating stations, machinery manufacturing and food processing, catering and other enterprises, all water directly in contact with oil contains oil. Discharging oily wastewater into rivers, lakes or seas, irrigating farmland, or discharging into urban sewage discharge systems, etc., will pollute the environment, affect the normal growth of organisms, or cause hidden dangers in disasters.

For the treatment methods of emulsified oil and dissolved oil, demulsification, coagulation, air flotation, and biochemical methods are commonly used, and some also use resin exchange or feather absorbing bags, but for the ballast seawater containing high-concentration gasoline and diesel oil. The treatment is not ideal.

  Mickey walnut shell abrasive provides a treatment process for the treatment of ballast seawater containing high-concentration gasoline and diesel oil tankers. The characteristic of this process is to make full use of natural conditions and new materials, and all are separated by physical and chemical methods.

Below we introduce this method: discharge the seawater from the oil-bearing ballast of the tanker into the sump, perform the grille, the initial sinking to remove the sediment and particles; then the oil is separated by aeration, and then the oil slick is removed by membrane filtration , The membrane used can be a water and oil barrier filter membrane, such as nylon and polypropylene non-woven fabrics. Then enter the secondary air flotation device, which can be an air flotation tower, and then filter through a secondary membrane to remove small-size floating oil and emulsified oil; then enter the filter of the nut shell medium, the nut shell medium abrasive can be walnut shell abrasive or For other husks, the best thickness of the husk abrasive is 300-600mm to get rid of the emulsified oil and dissolved oil. At this time, the general ballast seawater can meet the discharge standard. If the water quality is found to be unsatisfactory, you can continue to send the water to a single-stage or multi-stage series-connected PVF (low degree of condensation polyvinyl formal) membrane fine filtration device for further filtration, and the treated water can reach the standard discharge. A spare abrasive adsorption device can be installed behind the PVF fine filter device. The particle size of the abrasive is 1-1.5mm. The abrasive can be activated carbon, slag, coal ash, etc., to remove a very small amount of dissolved oil. The effluent is clear and transparent and contains oil. ≤5mg/L.