Anaerobic digestion of tannery waste: semi-continuous and anaerobic sequencing batch reactor processes.
Disposal of the vast amounts of tannery waste that are currently generated is a significant problem. Anaerobic treatment of different types of tannery waste (fleshings, skin trimmings and wastewater sludge) was investigated. The biochemical methane potential is the same at 37 degrees C or 55 degrees C and an assay of this was shown to be an appropriate screening tool with which to estimate the susceptibility of a substrate to anaerobic digestion. The start-up procedure of a tannery waste thermophilic anaerobic digestion in 100 days using seed from mesophilic digester processing municipal sludge is presented. The specific methane production potential at 55 degrees C is estimated to be 0.617 m(3)kg(-1) of volatile suspended solids for tannery waste sludge, 0.377 m(3)kg(-1) for tannery waste trimmings and 0.649 m(3)kg(-1) for tannery waste fleshings. Additional concerns such as chromium content, salinity and temperature fluctuations were also addressed. Chromium content and salinity showed no adverse effects; however a reactor temperature reduction of 4.4 degrees C led to a drop in biogas production of 25%, indicating a requirement to keep the temperature constant at 55 degrees C.
Zupancic
Gregor D
GD
National Institute of Chemistry, Laboratory for Environmental Sciences and Engineering, Hajdrihova 19, P.O. Box 660, SI-1001 Ljubljana, Slovenia. gregor.zupancic@ki.si
Jemec
A
A
D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D007220:Industrial Waste / Q000517:prevention & control*; D012722:Sewage / Q000382:microbiology*; D013633:Tanning; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
D007220:Industrial Waste; D012722:Sewage; D014874:Water Pollutants, Chemical