Water treatment technology for water purification equipment

Water treatment technology for water purification equipment

Physical filtration method

Physical filtration methods are mainly divided into: microfiltration, ultrafiltration, nanofiltration, and reverse osmosis.

① Microfiltration

a) Function: Retain particles

b) Use: Pretreatment of drinking water (coarse filtration)

c) Pore size: 0.1 Micron — Tens of microns

d) Classification: Flat plate (stainless steel plate), cylindrical (folded, melt-blown)

e) Retention mechanism: Mechanical, adsorption,

② Ultrafiltration

a) Function: Remove macromolecules (bacteria) and colloids, etc.

b) Use: Deep treatment of drinking water, RO System pretreatment

c) Pore size: 1 Nanometer (nanofiltration) —0.2 Micron (microfiltration)

d) Types: Plate type, hollow fiber, tubular, spiral wound

e) Precautions for use: Broken filaments, anti-pollution, rinsing, materials

③ Nanofiltration

a) Concept: Between reverse osmosis and ultrafiltration, general pore size 1—2nm 。

b) Function: Bacteria, viruses, colloids, organic matter, nitrates, hardness, etc.

c) Use: Deep treatment of drinking water, softening

④ Reverse osmosis (reverse osmosis water purification technology)

a) Function: Removal of salts, bacteria, viruses, organic matter, pesticides, etc.

b) Use: Seawater desalination, deep purification of drinking water, preparation of high-purity water, etc.

c) Pore size: < 0.1nm

d) Progress: Ultra-low pressure membrane, low pollution membrane, etc.

e) Classification: Flat plate, hollow fiber, spiral wound

f) Basic concepts: Recovery rate, desalination rate, water flux and its attenuation coefficient, grade and section

g) Influencing factors: Temperature, pressure, influent salinity, pH Value, recovery rate, etc.

h) Points to note: Control recovery rate, influent water quality, pollution prevention and cleaning, prevention of back pressure and seal leakage, etc.

Activated carbon adsorption method

a) Function: Adsorption of free residual chlorine, organic matter, heavy metals, etc.

b) Use: Deep treatment of drinking water, pretreatment of drinking water, household water purifiers

c) Classification: State —— Powdery, granular; material —— Coconut shell, other fruit shells, wood charcoal, coal-based

d) Process: Raw material —— Molding —— Carbonization —— Activation —— Product

e) Pore size distribution: Micropores < 4nm Account for 95% Above; mesopores (transition pores) 4—100nm Account for 5% Below; macropores > 100nm Account for less than 1%

f) Porosity: 0.6—0.9cm3/g ，Specific surface area 700—1200m2/g

Disinfection method ——Ozone, ultraviolet, chlorine dioxide, liquid chlorine

① Ozone ( O3 )

a) Ozone: An unstable light blue gas

b) The oxidation potential of hydrogen is 2.07V ，Directly oxidizes microorganisms to cause death

c) Application: Disinfection, reduction BOD and COD 、Decolorization, etc.

② Ultraviolet

a) Ultraviolet C （ 200-280nm ）、Ultraviolet B （ 280-315nm ）、Ultraviolet A （ 315-400nm )

b) Principle: Through photochemical reactions DNA strand breakage or DNA polymerization of groups in.

c) Effect: Intensity of 30000μW/cm2 ，contact time greater than 1s can kill most bacteria and viruses.

d) Uses: Treatment of drinking water

③ Chlorine dioxide ( ClO2 )

a) Principle: Strong oxidizing property

b) Uses: Disinfection of drinking water and wastewater, an ideal disinfectant.

④ Liquid chlorine

a) The most commonly used disinfectant in centralized water supply

Ion exchange softening

a) Function: Removal of hardness ions ( Mg2+ 、 Ca2+ etc.)

b) Uses: Softening of household water, softening and desalination of industrial water, etc.

c) Principle: Ca2++ 2NaR=CaR2+2 Na2+

e) Other treatment methods

① Electrodialysis ( EDI )

a) Function: Desalination to produce pure water

b) Uses: Boiler water, industries with high requirements

d) Advantages: Simple system, no regeneration system required

e) Disadvantages: Wastewater discharge, low water production capacity, high energy consumption, membrane fouling

Water purification equipment ——EDI electrodialysis equipment

② Membrane bioreactor

a) Concept: Combination of membrane separation technology and bioreactor

b) Function: Removal of biodegradable substances, while retaining non-biodegradable substances through membrane filtration.

c) Applications: Treatment of domestic sewage and industrial wastewater, advanced treatment of drinking water.

③ Photocatalysis

a) Photocatalysis: The TiO2 photocatalyst ( TiO2/Ti ) is fixed around the ultraviolet light ( 254 ) source, which is the photocatalytic device.

b) Applications: Removal of small molecular organic matter, degradation of algal toxins, etc.