ADI Systems’ Hybrid Anaerobic Reactor used at Korean Polyester Plant
Location: Ulsan City, Korea • Sector: Chemical & Pharmaceutical
The Tae Kwang polyester plant in Ulsan City, Korea.
The Client's Needs:
The Tae Kwang plant had an activated sludge system which was not meeting performance expectations due to overloading. To overcome this, Tae Kwang investigated separating out the high-strength ethylene glycol waste stream and pretreating it anaerobically to reduce the load on the activated sludge system.
After a successful in-house pilot study confirmed the anaerobic treatability of the ethylene glycol waste stream, Tae Kwang investigated several process alternatives. The ADl Systems' hybrid system was considered to be the most suitable means of treating ethylene glycol wastewater. As a result, ADI Systems' hybrid system was shipped to Korea, and ADI Systems’ Korean licensee was commissioned to design and build the hybrid reactor system.
The high-rate hybrid reactor combines two anaerobic processes: upflow anaerobic sludge bed (UASB) and upflow fixed-film (UFF). The lower 30-50 percent of the reactor volume is the UASB zone, where a flocculent or granular sludge develops. Most of the organic stabilisation occurs in this sludge bed.
The upper 50-70 percent of the reactor is the UFF section. In the UFF zone, a cross-flow type media is used, which provides an extensive surface area for the fixed-film biomass to develop and grow. This media is also effective at intercepting sludge bed solids and raw influent solids, and promoting their flocculation and return to the sludge bed below.
The hybrid reactor at Tae Kwang has a reactive volume of 500 m3 and a design loading of 10 kg COD/m3.d.
The compact design of ADl Systems’ hybrid reactor allowed it to fit into the small space available at the waste treatment site in Ulsan City.
The higher solids inventory in the hybrid reactor results in longer sludge retention times (SRTs). Longer SRTs improve the reactor’s ability to handle higher levels of toxic substances, shock loadings, and influent suspended solids.
The COD removal rate is estimated at 80 percent.