Industrial electroplating wastewater treatment and environmental protection


Electroplated wastewater treatment

A common synthetic surface treatment company, the company has chemical oxidation, anodic oxidation, zinc plating, zinc plating nickel alloy, chrome plating, copper plating, gold plating, nickel plating, silver plating, etc., and the waste water generated is very messy. .. The company’s wastewater is divided into six categories during the construction of the environmental protection facility. Integrated wastewater, copper-containing wastewater, oil-based wastewater, cyanide-containing wastewater, chromium-containing wastewater and desalination wastewater. There were many difficulties in the actual wastewater treatment, and the wastewater treatment was inadequate. The environmental design process for various wastewater treatments is as follows:

Integrated drainage

  • Integrated wastewater conditioning tank, reaction tank, settling tank, bag biofilter, PH feedback tank, outlet
    Chromium-containing wastewater
  • Chromium-containing wastewater conditioning tank, reduction reactor, integrated wastewater conditioning tank,
    Cyanide-containing wastewater
  • Cyanide-containing wastewater control tank, secondary oxidation reaction tank, integrated wastewater control tank,
    Copper-containing wastewater
  • Copper-containing wastewater regulation tank, reaction tank, sedimentation tank, integrated wastewater regulation tank,
    Oil-based drainage
  • Oil-based drainage control tank, air levitation machine, integrated drainage control tank,

Plating drainage

Please consult a professional and certified environmental company. Most electroplaters also use a wastewater treatment process. It is very representative. In practice, it is difficult to ensure that the wastewater treatment of most electroplating plants does not meet the standards. As environmental monitoring becomes more stringent, many electroplating plants cannot keep up with the pace of environmental protection. Reset the factory or suspend the emission permit.

The difficulties of integration are:

  • 1. The mixture of wastewater is seriousThe discharge of electroplated wastewater is very confusing (employees are of poor quality and are continuously placed to save time). Wastewater is not classified. The chemicals used in each wastewater are highly targeted to reduce costs. As a result, wastewater in each category is not properly treated and integrated water still falls short of standards.
  • 2. Use a lot of lime to make the water clear and reduce the cost. However, a large amount of sludge is generated, and sludge treatment incurs a wastewater treatment cost of 30 to 40%.
  • 3. The pH of tap water changes drastically and the pH of the reaction tank becomes unstable. When the pH becomes unstable, the settling tank becomes cloudy. The water quality is also unstable, so it’s good or bad.
  • 4. There is a contradiction in the treatment of different metal ions under different pH conditions, which is not considered in the design. The precipitation effect of zinc and aluminum 7-8 is good, and increasing pH dissolves the zinc and aluminum precipitates. Nickel, copper and phosphorus require higher pH values.
  • 5. The water treatment staff is not responsible and does not pay close attention to the details. For example, there is a problem with the inflowing water, and emergency measures cannot be taken in time. Various instruments and probes are calibrated and cleaned from time to time. The concentration of the prescribed drug is not adjusted according to the process requirements. To save time, the concentration is changed without permission.
  • 6. Surface treatment Industrial products must undergo extensive pretreatment prior to surface treatment. The degreased powder used here contains an emulsifier, and a large amount of emulsifier not only affects the COD content, but also affects the aggregation of the settling tank, and it is not ideal to enter the mud and settle. It has poor properties, and a large amount of suspended solids adheres to the upper layer of purified water from the settling tank.
    It redissolves in water when the pH is adjusted, causing excessive excretion of heavy metal ions.
  • 7. Copper and nickel ions are the most common pollutants of all heavy heavy metals. In particular, copper ions typically exceed standards after using expensive heavy metal collectors. There are several powerful complexing agents such as ammonia, pyrophosphates, low cost phosphates and organic acids.
  • 8. The COD of a typical surface treatment plant is about 200-300, which can be achieved with a small amount of treatment. However, some devices with electroless plating such as electroplated screws and small iron parts are protected by large amounts of oily material. A large amount of oil contamination due to the pre-manufacturing degreasing process can enter the sewer, resulting in a COD content of 500 or higher and a COD content of 20,000 in the electroless plating mother liquor.
  • 9. In some plants that use more cyanide, the cyanide treatment is incomplete, which is a very unfavorable factor for subsequent heavy metal ion standards.

solution:

  • 1. Comprehensive treatment of many wastewater treatment processes was performed using PTJ’s water treatment agent. For example, copper-containing water is mixed with chromium-containing wastewater (because copper phosphate is very unstable under acidic conditions). Oily wastewater is mixed with cyanide-containing wastewater and COD can be adequately removed during secondary oxidation of cyanide water.
    The top leader of the PTJ Company has set up a sewage drainage monitoring team to carry out irregular inspections of factory effluent. Workshop staff and managers are encouraged to pay attention to emissions, and top leaders focus on safety and environmental protection goals. Recognize that all employees and employees of a company can reduce the normal operations of some companies. If environmental protection does not meet the standards, it will be fatal to the company!
  • 2. Use a new water treatment agent instead of lime and caustic soda. There are XX water treatment neutralizers on the market. This effect is comparable to caustic soda, and the price is between lime and caustic soda. Corresponding drug doses are reduced and sludge production is also significantly reduced. The overall calculation reduces costs.
  • 3. Add a set of pH probes to the integrated water conditioning tank and test the pH of the inflow. Move the adjustment tank to the reaction pump lift pump linkage, set the PH above 5 and stop automatically. The reaction cell is equipped with a dedicated person for pH testing. Everyone is currently using PH’s auto-addition system. However, there are many factors that affect the pH, such as inaccurate pH, uneven mixing, fluctuating water, and the inability of the dosing pump to keep up. It is also recommended to use PH paper for frequent tests to ensure pH stability.
  • 4. Sewage treatment at high pH is mixed together for pretreatment. In this way, low pH can be controlled in an integrated reaction cell that saves some of the base, later reverses the pH of the acid and ensures that the pH at the outlet is stable. ..
  • 5. Work planning and aggregation, responsibility for manipulating employees is personal. Be aware of following the process. The exam must be stopped in time to regulate the sudden legal situation. Please resolve the issue before starting the process.
  • 6. Addition of 80 mesh of activated carbon to the integrated conditioning cell for adsorption increases the amount of coagulant.
  • 7. Recovery of heavy metals such as copper and nickel in the workshop can recover heavy metals and has a certain economic value.
  • 8. Chemical nickel effluent can be recovered as much as possible by a professional environmental protection company. For pretreated water containing a large amount of oil, a detonation pipe may be provided in the general adjustment tank to perform detonation, and a certain amount of activated carbon may be added.
  • 9. Cyanide treatment must be complete. Extra bleach can be detected on starch-potassium iodide paper.

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