The industrial wastewater treatment itself has complexity, and the composition of pollutants will directly affect the choice of treatment process. SBR technology, biological method, membrane separation method, iron-carbon micro-electrolysis treatment technology, ion exchange method, radiation technology ... This article collected 17 kinds of commonly used technology, briefly describe the technical characteristics.
Which of the 17 industrial wastewater treatment methods is "your cuisine"?
Industrial waste water includes production waste water, production waste water, and cooling water. It refers to the waste water and waste liquid produced during industrial production. It contains industrial production materials, intermediate products, by-products, and pollutants generated during the production process. There are many kinds of industrial wastewater and the components are complex. So what are the processing techniques? With stricter environmental protection requirements, we need to know more about the various waste water treatment processes. What are the mainstream technologies in the country and what are the results?
1, multi-effect evaporation crystallization technology
During the treatment of industrial salty wastewater, the industrial salty wastewater enters the low-temperature multi-effect concentration and crystallization device and is separated into desalinated water (diluted water may contain trace amounts of low-boiling organics) and concentrated after a 3 to 6-effect evaporative condensation crystallization process. Crystal slurry waste liquid; inorganic salt and some organic substances can be crystallized and separated, and incineration treatment is inorganic salt waste residue; non-crystallized organic matter concentrated waste liquid can be used as drum evaporator to form solid waste residue and incinerated; desalinated water can be returned to the production system instead of softening Use water.
The low-temperature multi-effect evaporation concentration and crystallization system can be applied not only to the concentration process and crystallization process of chemical production, but also to the process of evaporation, concentration and crystallization of industrial salty wastewater.
The multi-effect evaporation process only uses steam in the first effect, so the required amount of steam is saved, the heat in the secondary steam is effectively used, the production cost is reduced, and the economic benefits are improved.
2, biological method
Biological treatment is one of the most commonly used methods for wastewater treatment. It has a wide range of applications, strong adaptability, and economical and efficient.
Under normal circumstances, the commonly used biological methods are traditional activated sludge and biological contact oxidation.
(1) Conventional activated sludge process
The activated sludge process is an aerobic biological treatment of sewage, and it is currently the most widely used method for the treatment of urban sewage. It can remove soluble and colloidal biodegradable organics as well as suspended solids and other substances that can be adsorbed by activated sludge, as well as remove some of the phosphorus and nitrogen.
The activated sludge process has a high removal rate and is suitable for the treatment of wastewater with high water quality and stable water quality. However, they are not good at adapting to the changes in water quality. The supply of oxygen can not be fully utilized; the air supply is evenly distributed along the pool, resulting in excess oxygen in the early stage and insufficient oxygen in the rear stage; the aeration structure is huge and the area is large.
(2) Biological Contact Oxidation
The biological contact oxidation method is a method for organic sewage treatment mainly using microorganisms (ie, biofilms) attached to the surface of certain solid objects.
Biological contact oxidation method is a submergence biofilm method, which is a combination of biological filter and aeration tank. It also has the features of activated sludge and biofilm methods, and has a good effect in the water treatment process.
The biological contact oxidation method has a high volume load and has a strong adaptability to the impact load; the sludge generation is small, the operation and management is simple, the operation is simple, the energy consumption is low, and the economic efficiency is high; the activated sludge method has the advantages of biological It has high activity, good purification effect, high treatment efficiency, short processing time, and good and stable water quality. It can decompose other bio-treating substances that are difficult to decompose and has the function of deoxidation and phosphorus removal, and can be used as a tertiary treatment technology.
3, SBR process
SBR is an abbreviation of Sequencing Batch Reactor (SBR). As an intermittently operated wastewater treatment process, SBR has been widely considered and studied at home and abroad for a sewage treatment technology.
SBR's working procedures consist of five processes: inflow, reaction, precipitation, discharge, and idleness. Sewage enters each reaction process sequentially and intermittently in the reactor, and the operation of each SBR reactor also operates intermittently in sequence.
SBR method has the following characteristics: simple process, small footprint, less equipment, saving investment. The ideal push-flow process makes biochemical reactions have a large thrust, high treatment efficiency, flexible operation mode, phosphorus removal and nitrogen removal, high sludge activity, good settling performance, impact resistance load, and strong treatment capacity.
Although the SBR has advantages, it also has certain limitations. If the influent water flow is large, the reaction system needs to be adjusted to increase the investment; while the effluent water quality has special requirements, such as nitrogen and phosphorus removal, etc. Improve.
4, MBR process
MBR is a new high-efficiency wastewater treatment process combining high-efficiency membrane separation technology with traditional activated sludge process. It uses a unique structure of MBR flat membrane module placed in an aeration tank, after aerobic aeration and biological treatment. The water is pumped through the filter and pumped out.
The MBR process equipment is compact and occupies less land; the effluent quality is high and stable, and the organic matter removal efficiency is high; the surplus sludge production is less, and the production cost is reduced; the ammonia nitrogen and hard-degradable organics can be removed; and it is easy to transform from the traditional process. However, the high cost of membranes makes the capital investment of membrane bioreactors higher than that of traditional sewage treatment processes; membrane fouling is prone to occur, causing inconvenience to operation and management; high energy consumption and high process requirements.
5, electrolytic process
Under high salinity conditions, the wastewater has a high conductivity, which provides a good development space for electrochemical treatment of high salinity organic wastewater.
The high-salinity wastewater undergoes a series of redox reactions in the electrolysis cell to form water-insoluble substances, which are precipitated (or floated) or directly oxidized and reduced to harmless gases to reduce COD.
When the sodium chloride in the solution is electrolyzed, part of the chlorine gas generated on the anode is dissolved in the solution to cause a secondary reaction to generate hypochlorite and chlorate, and the solution is bleached. It is the above-mentioned synergistic effect that the organic contaminants in the solution are degraded.
Due to the limitations of electrochemical theory, high energy consumption, and lack of electricity, the current electrolytic treatment of high-salt wastewater is still in the research stage.
6, ion exchange method
Ion exchange is a unit operation process in which an exchange reaction between ions in solution and counter ions on insoluble polymers (containing fixed anions or cations) is usually involved.
In the ion exchange method, the wastewater first passes through a cation exchange column in which positively charged ions (Na+, etc.) are replaced by H+ and remain in the exchange column; thereafter, negatively charged ions (CI- etc.) are in the anion exchange column. Replaced by OH- for the purpose of desalting.
However, one of the main problems of this method is that the solid suspended solids in the waste water will clog the resin and lose its effect, and that the regeneration of the ion exchange resin requires high costs and the exchanged waste is difficult to handle.
7, membrane separation method
Membrane separation technology is a novel separation technology that uses membranes to separate, purify, and concentrate target substances by selecting the difference in permeation performance of each component in the mixture.
The commonly used membrane technologies are ultrafiltration, microfiltration, electrodialysis and reverse osmosis. When ultrafiltration and microfiltration are used in the treatment of industrial wastewater, they can not effectively remove the salinity in the wastewater, but can effectively retain the suspended solids (SS) and colloidal COD; electrodialysis and reverse osmosis (RO) are The most effective and commonly used desalination technology.
The main difficulties in restricting the application of membrane engineering technology are the high cost of membranes, short life span, vulnerability to contamination, and fouling and fouling. With the development of membrane production technology, membrane technology will be applied more and more in the field of wastewater treatment.
8, iron carbon micro-electrolysis treatment technology
The iron-carbon microelectrolysis method is a good process for treating waste water using the Fe/C galvanic reaction principle. It is also called internal electrolysis method, iron filings filtration method and the like. Iron-carbon microelectrolysis is a comprehensive effect of electrochemical redox, electrochemical electrolysis on the flocculation, and the condensation of electrochemical reaction products, adsorption of new flocs, and bed filtration. Redox and electroadhesion and agglomeration.
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