Biological Sulphate Reduction Using Primary Sewage Sludge As Energy Source In An Upflow Anaerobic Sludge Bed Reactor

ABSTRACT

BIOLOGICAL SULPHATE REDUCTION USING PRIMARY SEWAGE SLUDGE

AS ENERGY SOURCE IN AN UPFLOW ANAEROBIC SLUDGE BED REACTOR

Since the economics of biological sulphate reduction (BSR) are driven by the economics of

the organic carbon source, the BioSURE® process has been developed as a low-cost

effective system where primary sewage sludge (PSS) is used as the energy source. This

research investigates the use of PSS for BSR in an upflow anaerobic sludge bed (UASB)

reactor in detail in order to exploit and further develop this novel technology. From the

analyses of the extensive experimental data gathered, a number of significant outcomes have

been accomplished, namely:

1. The capabilities and limitations of BSR with PSS in a UASB reactor configuration at 2

operating temperatures, 35 and 20 oC and at different organic and sulphate loading rates

have been established. UASB reactor R1 (at T=35 oC) fed a PSS COD/Sulphate ratio of

1.25 (1875 mgCOD/1500 mgSO4

2-) achieved more than 90% sulphate reduction when

operated at its lowest optimal hydraulic retention time (HRT) of 13.5h and sludge age of

18d. When fed 1800 mgSO4

2-/L (PSS COD/SO4

2- = 1.44), R1 achieved >92% sulphate

reduction at its lowest optimal HRT of 18h and bed sludge age of 21d. UASB R1 effluent

sulphate and unfiltered organic COD concentrations were 93% sulphate reduction at its lowest optimal

HRT of 20.4h and bed sludge age of 24d. R2 effluent sulphate and unfiltered organic

COD concentrations were