Jiangxi Guangde Heavy Metal Wastewater Zero Discharge Treatment Project Case

Project Overview

Jiangxi Guangde Environmental Protection Company generates 150-200T/d of wastewater when recovering valuable metals from heavy metal sludge. Discharge is not allowed at the factory site. Sanrenxing Environment has developed industrial wastewater treatment equipment and equipped it with an 8T/H three-steam four-effect evaporation system, which can evaporate 200T/d of industrial wastewater.

I. The following are the causes of the troubleshooting table:

The evaporator heating tube wall is scaled and the crystal is blocked, which reduces the evaporation capacity.

The higher the concentration of the influent water for industrial wastewater treatment, the slower the evaporation, while the evaporation is faster when diluted.

Material corrosion causes equipment failure and the normal operation rate of the system is reduced.

II. The principle of the best solution is:

·Solve the problem and do not idle the existing 8T/H evaporation system.

·Improve energy efficiency, reduce operating costs, and use wastewater resources to generate benefits.

III. The reasoning approach to finding a solution is:

1. Organize and analyze the original wastewater quality data.

2. Establish a mathematical model (m-A3) of the concentration multiple (m) and the water quality change parameter (A3).

3. Make a NaCl-Na2SO4 coexistence saturation point curve.

4. Use the graphical operation method to find the process critical points of scaling, crystallization, and blockage.

5. Based on the principle of avoiding process critical nodes, establish a reasonable and feasible technical solution.

6. Macro-technical and economic evaluation.

Source of wastewater characteristics

Jiangxi Guangde Environmental Protection Company's main business is the research and development, production and sales of non-ferrous metals such as electrolytic nickel and electrolytic nickel copper. A large amount of heavy metal sewage and wastewater are generated during its research and development and production process.

Design inlet and outlet water quality

1. Inlet water quality

2. Design water quality:

Zero discharge of industrial wastewater project, using waste liquid evaporation to make Glauber's salt

Wastewater Process

Design process advantages

⑴ Direct softening of industrial wastewater, control of softening liquid Ca, Mg, CO3 equal to zero.

⑵ Softening liquid directly enters NFRO membrane, through membrane combination, pressure, flow control, make Na2SO4 interception rate 95%, NaOH + NaCl permeability 85%, the ratio of the two can be in the subsequent membrane filtration and evaporation without crystallization and clogging.

⑶ NFRO fresh water directly evaporates to produce NaCl + NaOH evaporation concentrate.

⑷ Utilize 60℃ tail gas refrigeration of evaporation system, freeze evaporation concentrate, crystallize NaCl, centrifuge to separate NaCl crystals and NaOH mother liquor.

⑸ Centrifuge mother liquor is mixed with NFRO concentrate, lime Ca(OH)2 is added at 0℃ for causticization reaction, and NaOH + CaSO4 is generated. There is a eutectic point in the (0～10℃) range, CaSO4·2H2O has the lowest solubility, and Ca(OH)2 has the highest solubility.

⑹ Filter press separates hydrated gypsum CaSO4·2H2O. Get high-quality NaOH liquid products.

Project pictures

Dongguan Environmental Protection Company Dongguan Sanrenxing Environmental Technology Co., Ltd. is an environmental protection management company integrating design, construction and operation. It has a mature wastewater treatment R&D team, wastewater analysis and laboratory testing team, wastewater treatment operation team, and engineering implementation and maintenance team to ensure that customers are provided with fast and accurate services. The main service directions are: industrial wastewater treatment, sewage station operation, evaporation and concentration equipment customization, etc. It is good at anodizing wastewater treatment and is familiar with a variety of wastewater treatment R&D and production processes. It controls the emission of pollution sources from the source and reduces the amount of sludge, which is more conducive to meeting emission standards and saving operating costs.