Q:What are the uses of industrial wastewater recovery and what are its water quality standards?
The use of industrial wastewater recovery can be divided into process water, cooling water and boiler water. Among them, process water is the largest, and the quality of process water depends on the quality of water required for each process attribute and the quality of water concerned. For the general industry, the tap water standard is the raw water quality of the process that each industry can accept.

Q:What are the common technologies for industrial wastewater recycling? What is the current trend?
The commonly used industrial wastewater recovery technologies include: Filtration, Microfiltration (MF), Ultrafiltration (UF), Adsorption, Oxidation, Reverse Osmosis (RO), Electrodialysis (ED), Ion exchange (IE), and Disinfection.
At present, the double-film process is commonly used for international industrial waste water recycling. This is because the RO reverse osmosis process can regenerate wastewater to extremely high quality and is suitable for all applications. In a typical design, the effluent water is first passed through the MF/UF system to remove particulate matter and larger colloids to reduce the fouling of the RO membrane, and also provides the opportunity to remove biological contamination such as bacteria and spores. The RO program is responsible for the removal of finer colloids and dissolved substances such as divalent ions and partially monovalent ions.

Q:The water fee in Taiwan is very cheap. Why do we still need wastewater recycling?
The cost of waste water recycling is naturally inconsistent with economic efficiency if it is compared with the water price of tap water. However, in addition to reducing water pollution discharge fees or sewage sewerage usage fees, waste water recycling can also provide a stable source of water quality and volume, and it is of great help in reducing environmental impact and enhancing corporate image.

Q:What is the principle of seawater desalination in Reverse Osmosis (RO)?

When a semipermeable membrane separates the solution from the pure solvent, the additional pressure, which is added to the solution and just enough to prevent the pure solvent from entering the solution, is called the osmotic pressure. Usually the higher the concentration of the solute in the solution, the higher the osmotic pressure. When the solution is not pressurized on one side, the pure solvent diffuses through the semi-permeable membrane to the side of the solution. This phenomenon is osmosis. On the contrary, if the pressure applied on the solution side exceeds the osmotic pressure, it can be in order to allow the solvent in the solution to flow to the pure solvent side, this process is called Reverse Osmosis.

Q:What is the purpose of pretreatment of seawater desalination RO procedures?
  • Ensure that the maximum SDI15 doesn't exceed 5.0;
  • Guarantee turbidity below 1.0 NTU, strive for less than 0.2 NTU;
  • Ensure that there is no residual chlorine or similar oxides;
  • Ensure that there are no other chemicals that may cause membrane fouling or deterioration.

*Note: SDI value - one of the most important indicators for measuring Reverse Osmosis system influent

Q:What are the indicators of RO membrane fouling? What kind of procedures can be used to solve the pollution problem to extend the life of RO membranes ?


Membrane pollution index allowance Solution
Suspended matter, etc. Turbidity <1 NTU Filtration, coagulation sedimentation, microfiltration, ultrafiltration
SDI15 <5.0 N/A
Particulates <100 / ml Filtration, coagulation sedimentation, microfiltration, ultrafiltration
Microorganism <1 per ml Sterilization, microfiltration, ultrafiltration
Metal oxide Iron, Fe3+ < 50 μg/L Oxidation + precipitation or filtration
Manganese, Mn < 50 μg/L Use dispersants
Molecule CaCO3 LSI<0 Recovery, pH, scale inhibitor
CaF2 <1.7 mg/L Recovery rate
Organic matter Oil 0 Floatation, adsorption
TOC <10 mg/L Activated Carbon, Filtration, Exchange Resin
COD <10 mg/L Activated Carbon, Filtration, Exchange Resin
BOD <5 mg/L Sterilization, microfiltration, ultrafiltration


Membrane Deterioration Index allowance Solution
pH value 3~10 Add acid or alkali adjustment
Temperature 5~45°C Heat exchanger
Oxidizer Residual chlorine <0.1 ppm Reducing agent, activated carbon adsorption
Ozone 0
Others 0
Alcohol  <10% N/A

Q: Is there anything fun or delicious for Matsu?
Of course! Details can refer to this fan page!
Matsu. Blue love