Economic impact of electrostatic precipitators pulse energization on dedusting in iron‐ore sintering plants

Investigates the application of the up‐flow anaerobic sludge bed (UASB) reactor for the anaerobic treatment of sewage sludge containing high concentrations of soluble and insoluble sulphides. Assesses the reactor’s performance in terms of volatile organic matter (VOM) and biogas production rate. The average percentage removal of VOM, total sulphide and biogas for the reactor operation without sulphide was 67 per cent, 65mgS/L and 1 L/day, respectively. The corresponding average percentage removal of VOM, total sulphide and biogas production rate for the experiment with 800mgS/L soluble sulphide was 45 per cent, 450mgS/L and 0.7L/day. Equilibrium concentrations of soluble sulphide up to 200mgS/L exert insignificant toxic effects, but toxicity increases as the concentration of soluble sulphide increases. A concentration of soluble sulphide of 1,200mgS/L produces severe toxic effects and the complete termination of gas production. An inhibitory concentration of sulphides affects gas production first, while significant volatile acid accumulation takes place much slower, and only after gas production has been severely retarded. Insoluble sulphide has an insignificant effect on the UASB up to a concentration of at least 800mgS/L. The addition of iron as ferric chloride prevents the toxicity of soluble sulphides as indicated by the minor effect on gas production. Therefore, the use of iron to precipitate sulphide could be used on a continuous basis to reduce sulphide toxicity.