Hazardous Waste Treatment
1. Treating by incineration method
The waste will be put into the incinerator batch by batch, fuel is DO. In the primary incinerator, fuel is pumped into the incinerator through the fire nozzles to burn the waste and always maintain the temperature in the incinerator at a temperature (550 - 6500c).
The gas produced after burning from the primary incinerator is directed through to the secondary incinerator to burn the remaining elements in the exhaust gas at higher temperatures (about 1000 - 1.2000C. Similar to the primary incinerator, DO fuel is injected into the secondary to maintain the temperature inside. Gas formed from waste incinerators will be directed through the heat exchanger to reduce the temperature below 3000C to avoid the formation of toxic Dioxin / Furan.
After cooling down process, gas is led through the absorbent device that has gasket ceramic rings inside. By contact process between gas phase and liquid phase (NaOH), components of acid gases such as HCl, HF, COX, SOx, NOx, dust ... are removed from exhaust gases prior to discharge into the environment through 20m high of chimney. The absorption solution is circulated and NaOH is added frequently to ensure appropriated concentration for treating process.
Periodically, the solution will be discharged into the wastewater treatment system and replace it by new solution. Heat generated from the treating process is utilized for drying the wastes and sludge to limit emissions of heat into the environment and save fuel for treating process.
Residue ash generated from burning will be conducted to solidify before moving to the landfill.
2. Treating by solidifying method
Before the solidifying process, materials should be crushed to appropriate size, and then put into the mixer machine for each batch. The addition agents such as cement, sand and polymer are added to carry out the dry mixing, and then continue to add water to do the wet mixing process. The mixing process helps for the components to be mixed and form the homogeneous mixture. After required mixing time, the mixture is added to the cube mold. After 28 days maintaining solid cube, solidifying process occurs and isolates completely contaminated components.
The solid cube will be tested the compressive capacity, the possibility of leak, and stored carefully in warehouse before transporting to the landfill.
3. Wastewater treatment
All types of wastewater are classified and stored in the separated container. These are simple stages but very convenient for following stages of treatment process, saving cost, optimizing technical process, including categories below:
- Wastewater containing hard biodegradable organic;
- Wastewater containing high content of heavy metals;
- Wastewater contaminating oil.
Wastewater treatment system at the plant is operated in batch form. In each batch, waste water is led into the regulation tank to stabilize the flow and wastewater concentration before discharge through next stages.
For wastewater contaminating oil, the first stage is separated oil by pressured flotation process before passing the regulation tank. Wastewater treatment process is complied with the following methods mentioned below:
- Mechanical treatment: sedimentation, filtration, separation and flotation.
- Chemical and physical processing: coagulation.
- Chemical treatment: oxidation at higher levels.
- Biological treatment: anaerobic (UASB), aerobic and treating nitrogen as batch processing with aerobic activated sludge.
4. Treating Fluorescent Lamp