BS ISO 23044:2020 pdf download
BS ISO 23044:2020 pdf download.Guidelines for softening and desalination of industrial wastewater for reuse.
7 Desalination process
Desalination processes based on ion exchange resin, RO, ED, EDI, and nanoliltration are suggested to be adopted according to iniluent and effluent quality requirements. The suggestion of desalination processes can be found in Table 3lJll, Other desalination technologies and their performance are shown in Annexfl.
As to ion exchange technology, if the ratio of strong acid anion to weak acid anion in the influent is relatively stable, in the primary desalination process, unit series system of cation and anion exchangers can be adopted, and resin volume of the anion exchanger should be the calculated value with 10 %—15 % margin plus.
If the ratio of strong acid anion to weak acid anion In the iniluent is changeable, in the primary desalination process, the parallel system of master control of the cation and anion resin exchanger should be adopted.
Electrodialysis is often combined with reverse osmosis. When the reverse osmosis process is placed behind, the reverse osmosis feed water is the fresh water of electrodialysis. When the reverse osmosis equipment is placed in front, the electradialysis feed water is the concentrated water of reverse osmosis.
The influent of EDI should be the effluent from RO with low hardness and conductivity. The effluent from EDI can be used as ultrapure water in Industrial production.
For ion exchange technology, both cation exchange on the hydrogen cycle and anion exchange on the hydroxyl ion cycle are required to achieve a reduction in dissolved solids.
Cation exchange resin can be regenerated with acid (e.g., sulfuric acid), while anion exchange resin can he regenerated with alkali (e.g., sodium hydroxide). regeneration solution should be heated when silicon content in influent is relatively high.
A. 1 Conventional treatment technologies
Conventional treatm..!nt includes primary treatment and secondary treatment. Primary treatment technologies (e.g.. screen, sedimentation, Iloatation, oil separation, etc.) and secondary treatment technologies (e.g., anaerobic process, aerobic process. etc.) can be adopted to remove suspended solids, grease and oils, dissolved and colloidal compounds and organic matters.
A.2 Tertiary treatment technologies
A.2.1 Coagulation and precipitation
Aluminium salts. lerric salts and polymeric Iloccuiants e.g., polyacrylamide) can he used as coagulant to remove residual suspended solids and organic matters, and both advection arid vertical flow type are applicable in precipitation tank design. Electrocoagulation is another pre-treatment alternative with lower resultant residual concentrations of dissolved inorganics.
A.22 Filtration
Filtration can be adopted to remove residual suspended solids and organic matters by choosing lifter tank e.g.. granular media, fibrous media, etc.), microfiltration (MF) or ultrafiltration (UF). Filter tank Includes dual•media filter tank, single layer filter tank or homogeneous media Filter tank. Dual- media filter tank can choose anthracite or quartz sand as media, while both single layer filter tank and homogeneous filter tank can also use quartz sand as media. Even with the use of MF or UF upstream of RO. cartridge filters are often used Immediately upstream of RO as an additional protective measure.
A.2.3 Advanced oxIdation
lithe biodegradability of organic matter in the iniluent is poor, ozone catalytic oxidation, electrolytic catalytic oxidation technology, electrochemical technology can he adopted to remove these organic matters or improve the biodegradability of these organic matters.
A.2.4 Aerated biofiltration
lithe biodegradability of organic matter in the influent is relatively good (HOL).JCOL) 0.2). aeration
biofiltration can be adopted to remove these organic matters.
A.2.5 Activated carbon adsorption
Activated carbon can be used to improve water quality by removing smell and organic matters in water. Activated carbon adsorption process uses granular activated carbon media filters. And the filter bed can apply iluidized bed or moving bed.
