AOP – ADVANCED OXIDATION PROCESS
The advanced oxidation process is defined as the oxidation process based on the hydroxyl radical (·OH), which created in the reactor in a short time. Hydroxyl radical is one of the strongest oxidation agents, could oxidize all organic substances, and transfer them into nontoxic inorganic substances (mineralization) such as CO2, H2O, or degradable substances such as short-chain organic acids, inorganic acid.
This process is typically applied in treating wastewater with a high concentration of hardly degradable COD and color. The oxidation process can be used in the tertiary treatment step to remove remaining COD and color or used in the first chemical treatment step (before the biological treatment step) to increase the BOD/COD ratio.
The picture below is a description of one Koastal Eco’s plant using the Fenton process for advanced oxidation treatment with capacity 1,500 m3/day.
MFT – MULTILAYER FILTER TANK
This filtration system consists of pressurized filters with many filtration materials layers and many dimensions. The material arrangement can remove large suspended solids at the first material layer, and the smaller suspended solids are retained in a deeper material layer, so the removal of suspended solids is higher and turbidity is lower.
This process is typically applied in projects with high treated effluent or with recycling for a simple purpose such as irrigation, washing belt filter press.
Project scale Koastal Eco applied for a pressured filter is up to 1,500 m3/day.
UF - ULTRAFILTRATION
UF is used for separation of suspended solids, colloids with membranes pore size between 20nm – 0.1µm under low operating pressure. This filtration step can be considered as the raw filtration step before going through RO system (if any). A typical application of this membrane is MBR technology (see also the section in Biological treatment process and Wastewater recycling process).
Application in recycling: treated effluent can be reused for road cleaning, car washing, landscape irrigation, toilet flushing.
The current recycling of water in Vietnam is often applied to only a part of the capacity of the wastewater treatment plant due to cost restrictions. The size of the UF Koastal Eco system used for water reuse is 25 m3/h.