Abstract
Wastewater from sludge drying process in sludge melting system contains both ammonium trogen and dissolved organic compomds in high concentrations.It also contains inhibitory organic cnoimpounds to nitrification, which are biodegradable and absorbable to granulated activated carbon (GAC). The inhibition is transitory as nitrification acdvity recovers immediately after the inhibitory compounds are removed. With combination of several pretreatment methods for concentration and extraction such as Sep-Pak C18 concentration, GACex action, vacuum evaporration and liquid-liquid extracdon, and GC-MS analysis, paramethylphenol (p-cresol) is determined as a main inhibitory organic compound to nitrificahon in the wastewater. From the inhibition test with standard reagent of p-cresol, the 90% inhihibitory concentration is detennined to be 10 mg·L-1. P-cresol is also shown to be biodegradable and absorbable to GAC, that indicates the availability of treatment with biological activated carbon (BAC).
