1、 Overview of Leather Wastewater Treatment Equipment

Leather is a must-have in today's society, including shoe leather, luggage leather, glove leather, equipment leather, industrial leather, etc. Due to its applicability to various industries and the overall improvement of the domestic leather industry market, many small leather factories have rapidly expanded and developed. The large-scale discharge of leather wastewater has had a serious impact on the environment. The country's environmental protection requirements for the leather industry are constantly increasing, and there are higher technical requirements for leather equipment in terms of environmental protection and emission reduction. Therefore, designing a set of wastewater treatment processes with lower operating costs and better treatment effects is an urgent problem that the leather industry needs to solve. Dongguan Gaoda Environmental Protection Technology Co., Ltd. has developed and produced leather wastewater integrated treatment equipment, which is a high-tech environmental protection product specialized in purifying the wastewater generated by leather factories to meet the national unified discharge standards. The leather wastewater treatment equipment is carefully designed and a reasonable engineering budget is prepared to achieve design cost control of the project.

2、 Characteristics of Leather Factory Wastewater

Leather wastewater is not only large in volume, but also complex in composition and high in pollutant concentration, making it difficult to treat. Wastewater mainly comes from pre tanning preparation, tanning, and other wet processing sections. The most heavily polluted types of wastewater are degreasing wastewater, ash leaching and hair removal wastewater, and chrome tanning wastewater, which account for about 50% of the total wastewater volume, but contain the vast majority of pollutants. The mass fractions of various pollutants in their total amount are: CODcr80%，BOD575%，SS70%， Sulfide 93%, sodium chloride 50%, chromium compound 95%. Generally speaking, tannery wastewater is toxic. Harmful wastewater (sulfur-containing and chromium containing wastewater) accounts for 15-20% of the total wastewater volume. The chromium content in the wastewater from the chrome tanning process ranges from 2 to 4 g/L, while the sulfide content in the ash alkali depilation waste liquid can reach 2 to 6 g/L. These two types of concentrated wastewater are the focus of leather wastewater prevention and control.

3、 Attention should be paid to the treatment of leather wastewater

If the wastewater contains a large amount of calcium and iron ions, using fiber fillers can achieve good initial operation results. However, over long-term operation, calcium and iron ions are prone to adhere to the surface of the fibers and form scales, causing fiber calcification, brittleness, and fracture, resulting in increasingly poor treatment effects. If the frequent replacement of fillers increases the burden on the enterprise, the contact oxidation process should be used with caution in the treatment of such tannery wastewater.

4、 Leather wastewater treatment equipment technology

1、 The single treatment technology includes 1. The degreasing wastewater treatment methods include acid extraction, centrifugal separation, or solvent extraction. The widely used method is acid extraction. 2. Treatment methods for soaking and depilation wastewater include acidification, chemical precipitation, and oxidation. 3. Treatment methods for chrome tanning wastewater include alkaline precipitation and direct recycling.

2、 The comprehensive industrial wastewater treatment technology includes 1. Biochemical treatment process ① Pre treatment system: mainly including treatment facilities such as grid, regulating tank, sedimentation tank, air flotation tank, etc. ② Biological treatment system: The ρ (CODcr) of tannery wastewater is generally 3000-4000 mg/L, and the ρ (BOD5) is 1000-2000mg/L, which belongs to high concentration organic wastewater. The m (BOD5)/m (CODcr) value is 0.3-0.6, suitable for biological treatment. 2. The physical and chemical treatment methods for treating tannery wastewater include adding coagulants, internal electrolysis, and other technologies.

3、 Common process combinations include:; 1. Coagulation sedimentation+SBR method 2. Air flotation+contact oxidation method 3. Physical and chemical+oxidation ditch 4. Anaerobic+aerobic

5、 Reclaimed water system for leather wastewater treatment

Physical and chemical disinfection processes can be used, as follows:;

Source Water --->Regulating Tank --->Filtration Tank --->Disinfection Tank --->Storage Tank --->Discharge When using residential sewage as the source of reclaimed water, the biochemical+disinfection process can be used, as follows: Source Water --->Hydraulic Screen --->Regulating Tank --->Biochemical Tank --->Filtration Tank --->Disinfection Tank --->Storage Tank --->Discharge The above process facilities can be designed as above ground or underground structures according to the specific situation on site.

Parameters of Leather Wastewater Treatment Equipment

6、 What should I pay attention to when purchasing leather wastewater treatment equipment?

1. Understand the materials used in the equipment

There are usually two types of materials used for buried equipment: fiberglass and carbon steel. When purchasing equipment, it is necessary to inquire with the supplier about the materials used. When the process and other conditions are the same, the price of different materials will vary greatly.

2. Go to the supplier's successful case site to observe the effect

Everything should be based on facts. No matter how the supplier who provides you with the equipment introduces its superior performance, you should ask the supplier to provide previous successful cases and then send someone to inspect its on-site sewage treatment effect. Although it may delay some time, it is indeed crucial.

3. Agreed execution standards for water discharge

Many units fail to specify the standard for sewage treatment in the contract when purchasing buried sewage treatment equipment, which can lead to disputes in the future when environmental protection requirements are raised. Due to different levels of treatment, the cost of sewage treatment can vary greatly.

4. Compare and sign contracts before purchasing, and specify the payment process

Choose several suppliers as references, and then compare their adopted processes, successful cases, prices, and other factors comprehensively.

Sign a formal contract and agree on the delivery, commissioning, and payment process before paying the deposit.