Assessment of the toxicity of heavy metals to the anaerobic digestion of sewage sludge

Abstract

The effect of heavy metal concentration to the anaerobic sludge digestion process is studied by means of simple batch bioassay tests. Daily gas production rate and percentage volatile solid reduction decreased with increasing solids concentration. Analysis of the results by least square showed that gas production rate was directly proportional to the concentration of metals in sludge expressed as milliequivalent per litre. Threshold values for inhibition and toxicity limits, corresponding to 20% and 50% decrease in gas production respectively, are derived from the experimental results and can be used as a tool for diagnosis of potential toxicity.

Bismuth‐Doped Ordered Mesoporous TiO2: Visible‐Light Catalyst for Simultaneous Degradation of Phenol and Chromium

“…[23,24] Organic pollutants, including phenol, naphthalene, and trichloroethylene, have been found at high concentrations in water containing chromium(VI). [25] Environments contaminated by chromium(VI) and its aromatic copollutants include groundwater aquifers, lakes, river sediments, and soils.…”

Impact of metals on the biodegradation of organic pollutants.

“…The impact of metals on litter decomposition, methanogenesis, acidogenesis, nitrogen transformation, biomass generation, and enzymatic activity all have been studied (Babich and Stotzky 1985;Bardgett and Saggar 1994;Burkhardt et al 1993;Capone et al 1983;Doelman and Haanstra 1979a,b;Hickey et al 1989;Knight et al 1997;Kouzelikatsiri et al 1988;Lin 1993;Masakazu and Itaya 1995;Mosey 1976;Nandan et al 1990;Pankhania and Robinson 1984;Rogers and Li 1985). Metals including copper, zinc, cadmium, chromium (III and VI), nickel, mercury, and lead are reported to inhibit each of these processes.…”

Start‐up of low temperature anaerobic reactors using freshwater methanogenic sediments

“…Sewage sludge was obtained from a municipal sewage treatment facility. The total solids concentration was 32 kg.m" 3 , and significant amounts of heavy metals were present in the substrate, thereby suggesting potential toxicity effects (14). This substrate was selected because its low-temperature digestion would permit a higher energy recovery at sewage treatment plants.…”