Car wash wastewater treatment process

Ⅰ Car wash wastewater treatment process

 

While saving costs, it meets the reuse standards and helps the car wash industry to efficiently solve the sewage problem. Shanqing Environment usually uses the following processes to treat car wash wastewater until the wastewater is recycled.

 

1. Processing technology

 

1.1 Physical processing technology:

 

Sedimentation method: Through the action of gravity, the suspended matter in the wastewater is naturally settled and separated from the water to achieve the purpose of purification.

 

Filtration method: The suspended matter in the wastewater is intercepted by filtering media to achieve the purpose of purification.

 

Adsorption method: Utilize the adsorption effect of adsorbents to adsorb harmful substances in wastewater on the surface to achieve purification purpose.

 

1.2 Chemical treatment technology:

 

Neutralization method: By adding acid or alkali to the wastewater, the pH value is adjusted to convert harmful substances in the wastewater into harmless substances.

 

Redox method: By adding oxidants or reductants to the wastewater, harmful substances in the wastewater are oxidized or reduced to harmless substances.

 

Coagulation method: By adding coagulants into the wastewater, the colloidal substances in the wastewater are condensed into large particles and separated by sedimentation.

 

1.3 Biological treatment technology:

 

Haoyang biological treatment: By introducing air or oxygen into the wastewater, the oxygen required for the growth of microorganisms is provided, and the metabolism of microorganisms is used to convert organic matter in the wastewater into harmless substances.

 

Anaerobic biological treatment: By cultivating anaerobic microorganisms under anaerobic conditions, the organic matter in the wastewater is converted into gases such as methane through their metabolism.

 

2. Treatment process

Process introduction: This system is designed as a 2T/h reclaimed water reuse system .

 

Process description: Physical methods are used to remove impurities in water, the water output is good, the equipment is easy to install, the footprint is small, and the use is economical. However, each process requires frequent backwashing, the activated carbon needs to be regenerated after a period of use, and the precision filter element also needs to be replaced regularly.

 

2.1 Raw water pool

 

The raw water pool is used to store wastewater after car washing. Some sediment will settle in the wastewater, acting as a sedimentation tank.

 

2.2 Raw water pressure pump

 

The sewage in the raw water pool is pressurized and transported to the pretreatment equipment , ensuring that the sewage has sufficient power during the filtration process .

 

2.3 Quartz sand filter

The quartz sand filter is used to remove large impurities such as sediment and suspended solid particles in the incoming water .

 

During operation, large particles of impurities are trapped on the surface of the filter layer. After a period of operation, the impurities on the surface of the filter layer will gradually increase, and the pressure difference of the filter layer will also increase. After a certain period of time, the filter layer will be penetrated and the filtering capacity of the filter layer needs to be restored through the backwashing process. Therefore, a regular backwashing program must be set during the entire automatic operation process. The frequency of backwashing depends on the pressure difference between the inlet and outlet points of the filter or the operating cycle of the filter. Under normal circumstances, we recommend that backwashing should be performed when the pressure drop value is 0.7 bar or when it runs for 24 hours.

 

During backwashing, the water flow direction is opposite to the running direction. The filter layer is lifted and expanded under the action of large flow backwash water. The fouling substances are separated from the filter layer along with the backwash water flow and discharged from the tank from the top, thus achieving the purpose of backwashing .

 

2.4 Activated carbon filter

 

Function and effect

 

Its adsorption capacity is mainly reflected in the following aspects:

 

⑴Can adsorb organic matter, colloidal particles and microorganisms in water;

 

⑵Can adsorb non-metallic substances such as chlorine, ammonia, bromine, iodine, etc.;

 

⑶ Can adsorb metal ions, such as silver, arsenic, bismuth, cobalt, hexavalent chromium, mercury, antimony, tin and other ions;

 

⑷ Can effectively remove color and odor. Filter out chemical organic matter, heavy metals, color, odor, chloride ions, etc. in water .

 

2.5 Security Filter​

Function and effect:

 

The security filter is set before the ultrafiltration to prevent large particles in the water from entering the ultrafiltration membrane and ensure the normal operation of the ultrafiltration system . The security filter is a vertical columnar device with a PP spray filter element installed inside, and the filtration accuracy is 5μm. Colloid and particle fouling can seriously affect the performance of the ultrafiltration membrane element .

 

Features:

 

1. It can effectively remove suspended matter, impurities, rust and other substances in the liquid.

 

2. Able to withstand higher filtration pressure.

 

3. The unique deep mesh structure inside the security filter enables the filter element to have a higher slag load capacity.

 

4. The filter element can be made of a variety of materials to meet the needs of various fluid filtration.

 

5. The security filter has a small size, large filtration area, small resistance and long service life.

 

6. Resistant to acid and alkali chemical solvents, can be used in filtration equipment in the chemical industry.

 

7. High strength, high temperature resistance and the filter element is not easy to deform.

 

8. Low price, low operating cost, easy to clean the filter, convenient operation, replaceable filter element, and long filter service life.

 

9. Small filtration resistance, large liquid flux and strong pollution interception ability.

 

2.6 Ultrafiltration

Function and effect

 

Using new hollow fiber filtration technology, combined with three-stage pre-treatment filtration, the ultrafiltration micropore is less than 0.01 micron, which can completely filter out harmful substances such as bacteria , rust, colloids, etc. in the water. In the car wash wastewater, it mainly removes macromolecular compounds, clay, minerals, emulsion particles, microorganisms, grease, detergents, oil, and water emulsion.

 

2.7 Ultraviolet sterilizer​

 

Function and effect

 

(Total Organic Carbon) and other residual organic matter in water . Ultraviolet light can kill 99.9% of bacteria, as well as viruses, fermentation products, mold and algae.

 

Car wash wastewater is reused through the "recycled water reuse" treatment process, solving the problems of recycling car wash wastewater, removing harmful substances in the water, saving water resources, and improving environmental pollution.