Effect of preparation conditions and washing of activated carbon from paper mill sewage sludge on its adsorptive properties.

Sludge-based activated carbon (SAC) was prepared from paper mill sewage sludge by physical activation with steam for wastewater treatment in this study. The effects of preparation variables, including carbonization temperature, carbonization time, activation temperature and activation time, on iodine number and yield were investigated through orthogonal experiments. The influences of washing by deionized water and acid on the characteristics and adsorption capacities of SAC for phosphate, methylene blue and reactive red 24 were also studied. The results indicated that the optimal preparation conditions were: carbonization temperature of 350 °C, carbonization time of 40 min, activation temperature of 800 °C and activation time of 20 min. The characteristics and adsorption capacities of SAC were obviously different before and after washing, especially by acid. The surface area was improved and adsorption capacities for dyes increased after washing, while adsorption capacity for phosphate decreased. The maximum adsorption capacities provided strong evidence of the potential of SAC as an alternative adsorbent for wastewater treatment.

Microbial treatment of the monosodium glutamate wastewater by Lipomyces starkeyi to produce microbial lipid.

The monosodium glutamate (MSG) wastewater as a medium was treated by Lipomyces starkeyi to produce microbial lipid in the study. The effect of related factors (initial glucose concentration, inoculation concentration, initial culture pH, and cultivation time) on biomass, lipid production and lipid content was discussed, respectively. According to the experiments, the optimal fermentation conditions were determined: addition of 80g/L glucose, 10% inoculation concentration, initial pH about 5.0, incubation time 96h. Under this condition, the biomass production reached up to 4.61g/L, lipid production and lipid content was 1.14g/L and 24.73%, respectively. Simultaneously, protein and COD removal rate was 78.60% and 74.96%, respectively. The main composition of fatty acid in the resultant lipid was analyzed by gas chromatography-mass spectrometry, which showed: oleic acid (C18:1) 35.85%, palmitic acid (C16:0) 19.91%, palmitoleic acid (C16:1) 17.65%, and myristic acid (C14:0) 16.03%.