| Photochemical process |
The formation of by-products and power consumption |
No sludge production, rapid, high efficiency, simple operation |
| Membrane separation |
Short lifetime, economically unfeasible |
High efficiency, reuse salts |
| Electrochemical process |
High electricity consumption and economically unfeasible |
High efficiency, rapid |
| Ion change |
Economically unattractive, ineffective to certain dyes |
No loss of sorbents |
| Coagulation/flocculation |
High sludge production and disposal issues |
Simple, economically attractive |
| Adsorption |
Ineffective to certain dyes, the regeneration is costly, exposing adsorbent residue is also an issue, as loss of adsorbents |
Low cost, won't form hazardous substances |
| Biodegradation |
Occupy a certain land area, require strict external environmental conditions, and slow process |
Economically attractive and simple |
