Premium
Fate of semivolatile organic compounds during heat drying of mixed primary and waste‐activated sludge
Author(s) -
Bandyopadhyay Subrata,
Bhattacharya Sanjoy K.,
Farrell Joseph B.
Publication year - 1995
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143095x131196
Subject(s) - chemistry , activated sludge , chromatography , wastewater , mixed liquor suspended solids , extraction (chemistry) , environmental chemistry , sewage treatment , sewage sludge , waste management , engineering
The fate of semivolatile organic compounds was studied during heat drying of mixed primary and waste‐activated sludge. Selected organic compounds were spiked in the sludge collected from a wastewater treatment plant. The thickened sludge samples were heat dried in a tube furnace at different temperatures with a constant airflow rate. The exhaust air from the furnace was condensed in a glass condenser. Methanol was used as the solvent for extraction of compounds from both the dried sludge and the condensate. The concentrations of the organics were determined from high performance liquid chromatography (HPLC) analysis. The selected semivolatile organic compounds showed a high affinity to remain adsorbed in the thickened sludge. Drying sludge to more than 90% solids content caused complete removal of all of the organic compounds. The removal of organics took place in three distinct phases: a high removal in the initial phase, a sudden drop in the intermediate phase, and an increase in the final phase. Removal of phenol was approximately proportional to moisture removal from the sludge. For 4‐nitrophenol and nitrobenzene, the removal rate decreased as the amount remaining in sludge diminished. The removal pattern of the individual organics correlated with their respective Henry's law coefficients. At higher temperatures, a faster removal rate was observed for all the compounds.