Jumpei Aizawa

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Heavy metals removal without phosphorus loss from anaerobically digested sewage sludge was investigated by conducting batch experiments using hydrogen peroxide and/or iron sulphate under acidified conditions at pH 3. The addition of hydrogen peroxide to the sludge improved the elution efficiencies of As, Cd, Cu and Zn with phosphorus loss from the sludge.(More)
The diffusion coefficients for glucose and oxygen through the microbial aggregate were measured, and then the dependency on the biochemical factors was investigated. Kinetic and diffusion studies were carried out experimentally for this purpose. Both coefficients were found to be dependent not only on the bacteria concentration but also on the C/N ratio of(More)
The utilization of indigenous sulfur-oxidizing bacteria and sulfur waste was investigated in order to remove heavy metals from anaerobically digested sewage sludge economically. Indigenous sulfur-oxidizing bacteria existing in anaerobically digested sewage sludge were activated by adding elemental sulfur to the sludge and then the bacteria were isolated. It(More)
Chemical and biological leachings of As and metals from sewage sludge were carried out using a batch reactor under an aerobic condition. Addition of phosphate to the sludge was ineffective for the elution of As from the sludge at neutral pH. Akalization of the sludge to pH 11 eluted sufficient As, whereas it was ineffective for Al, Cd, Mn and Zn.(More)
Heavy metals in sewage sludge were classified into three partitions associated with extracellular and intracellular organic matters and the residue before and after different elution processes of heavy metals from the sludge. Alkalization of the sludge to pH 11 decreased the content of Cu in the three partitions and that of Ni in extracellular organic and(More)
The behaviour of As(III), As(V), MMA(v) and DMA(v) in batch activated sludge process were investigated. Experiments were carried out by using aerobic and anoxic reactors with an initial As concentration of 100 microjg I(-1). Under aerobic condition, As(III) was oxidized to As(V) within 9 hours, some part of MMA(v) was methylated to DMA(v) and some other(More)
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