[Case Study:Screw Press]–Zhejiang Fengdao Project

1. Project overview

Zhejiang Fengdao Group is located in Xinchang County, Shaoxing City, Zhejiang Province. It is the country's first batch of leading enterprises in agricultural industrialization. The group company has 8 subsidiaries. It has formed six product series including fruit and vegetable beverages, canned fruits and vegetables, and quick-frozen fruits and vegetables. Products are exported to the United States, Japan, South Korea and the European Union and other countries and regions. The marketing network is spread all over the world.

Fengdao Food Co., Ltd. is a subsidiary of Fengdao Group. It mainly produces all kinds of canned food. It mainly produces canned fruits such as peach, orange, pear and apple. The company produces a large amount of production and cleaning waste water in the production process of cans. This project used to have a set of waste water treatment equipment. Due to increased production and poor treatment of high concentration water, the discharged water quality cannot meet existing environmental standards. Therefore, it is necessary to upgrade the high concentration water.

In order to stick to the company's environmental protection and social responsibility and protect the water environment around the enterprise, the enterprise leaders required that the waste water should be treated effectively and then discharged after meeting the local environmental protection requirements. Our company has many years of working experience in the water treatment industry. Based on the specific waste water quality indicators of the project, we provide the following treatment design scheme.

2. The amount of water designed

According to the requirements of the customer, only the high-concentration waste water discharged was modified and treated this time. The daily discharge of high-concentration waste water is 800-1000m3, and the designed capacity of high concentration waste water is 50m3/h.

3. Inlet and outlet water quality indicators

According to the information provided by the customer, CODCr of high concentration waste water is between 800 and 10000mg/L.

The PH value of raw water is within the range of 7-8, and the removal rate of insoluble pectin in waste water can reach 95% in the high concentration water treatment system. The water outlet CODCr of the air flotation system is less than 2000mg/L.

4. Description of reconstruction engineering process  

According to the existing process, the high concentration waste water is collected separately by the production plant and then put into the waste water treatment station. A new water screen is added to intercept and remove the peel and core contained in the waste water. The waste water flows into the regulating tank by itself. According to the pH value of the waste water, acid and alkali are speculated in the regulating tank. Meanwhile, air blast and aeration are set in the tank. After the adjustment of the regulating tank, the waste water will be raised to multi plate screw press for fruit and vegetable industry, and most SS and pectin in the high concentration water will be squeezed out, so that the COD of the waste water will be greatly reduced.

After the pressed fruit residue is transported and disposed, the filtrate enters the intermediate tank and is lifted into the pressure dissolved air flotation machine. The SS and colloids in the waste water are further removed by the flotation function of the air flotation machine. The organic content has been greatly removed and entered the original biochemical system of the waste water station. Through the metabolic function of microorganisms, the organic pollution is thoroughly degraded, and the water is discharged up to standard. The remaining sludge of the floating scum and biochemical system is discharged into the sludge tank. The sludge is dewatered by the original screw press, and the sludge cake is transported outside and treated after dehydration. The filtrate enters the fresh water regulating tank for recycling treatment.

5. Technological characteristics 

a. The processing technology has reliable operation, stable effect, high processing efficiency and strong ability to resist impact load.

b. The combination of each unit of the treatment process is reasonable, and has greater flexibility and room for adjustment, and has strong operational flexibility.

c. It is easy to operate and manage, and convenient to operate and maintain.

d. The process is compact. The treatment effect is guaranteed while saving the engineering investment, and running cost is low.

6. System anti-corrosion

a. The main body or axle parts of equipment such as water pump and mixer are corrosion resistant metal or plastic.

b. The pipes for dosing and underwater parts shall be made of UPVC or HDPE.