The compartmentalized anaerobic reactor(CAR)has outstanding potential in wastewater treatment engineering.The flow patterns of CAR were investigated through pulse stimulus-response technique using sodium fluoride as tracer

and were analyzed by means of the axial dispersion(AD)model and the tanks-in-series(TIS)model.The results showed that back-mixing was small and flow pattern tended to be plug-flow at normal loading rate

Peclet numbers of AD model under the condition with or without biogas production were 5.66 and 7.94 respectively

N numbers of TIS model under the condition with or without biogas production were 3.44 and 4.55 respectively.Back-mixing was large and flow pattern tended to be completely mixed flow at high or super-high loading rate

Peclet numbers of AD model under the condition with or without biogas production were 2.57

4.02 and 3.77

3.93 respectively

N numbers of TIS model under the condition with or without biogas production were 2.00

2.66 and 2.51

2.62 respectively.Average total dead space of CAR was 33.58%

of which average hydraulic dead space was 13.58%.Regression equation was established for parameters of hydraulic dead space(Vh)

volumetric hydraulic loading rate(L)and volumetric biogas production rate(G).The effect of volumetric biogas production rate(G)on hydraulic dead space(Vh)was less than that of volumetric hydraulic loading rate(L)in CAR.