Srr. Esteves et al., On-line monitoring of anaerobic-aerobic biotreatment of a simulated textile effluent for selection of control parameters, ENV TECHNOL, 21(8), 2000, pp. 927-936
Parameters monitored on-line in a laboratory biological wastewater plant tr
eating simulated textile effluent were examined for use in a control strate
gy. The plant, an anaerobic (UASB) reactor with an aerobic stage and overal
l HRT 1.8 days, was operated at steady-state and transient conditions with
varying ratios of azo dye and starch. Gas flow rate, %CO2, biogas hydrogen
levels and effluent bicarbonate alkalinity were assessed on-line in the ana
erobic stage, together with on-line measurements of effluent total oxygen d
emand (TOD), colour, pH, and dissolved oxygen. Their ability to indicate pr
ocess instability and efficiency, the reliability/maintenance of the instru
mentation and delay in response were evaluated. On-line TOD measurement fai
led due to the wastewater's mineral content; biogas hydrogen content varied
unpredictably. It is recommended that the other measurements be used toget
her in a control system for textile effluent biotreatment, providing comple
mentary information and redundancy.