Abstract
This study aimed to identify the factors that affect precipitation separation and in turn, sewage treatment. The respective lengths of the intake and outflow pipes and the tank configuration, that is, the use of a single or double tank, were identified as the main factors. Experiments were conducted using the Morrill index, which allowed for evaluation of water flow within the tank, referred to as plug flow. Furthermore, toilet paper was used as simulated sludge to evaluate the sludge outflow concentration. The boundary of the sediment was photographed for evaluation. Based on the results of an overall evaluation, of the intake and outflow pipe lengths, we recommend a 2/3 intake and 1/3 outflow pipe configuration without the use of baffles for separation tanks with a single-tank configuration.（After evaluation of the lengths of intake and outflow pipes, results suggested that a 2/3 intake to 1/3 outflow pipe ratio, without the use of baffles, was the optimal configuration for a single separation tank.）Where a single tank is divied into two, a volume ratio of 0.5 in advection for the intake and outflow pipes was found to be optimal. ABSTRACT This study aimed to identify the factors that affect precipitation separation and in turn, sewage treatment. he respective lengths of the intake and outflow pipes and the tank configuration, that is, the use of a single or ouble tank, were identified as the main factors. Experiments were conducted using the Morrill index, which llowed for evaluation of water flow within the tank, referred to as plug flow. Furthermore, toilet paper was sed as simulated sludge to evaluate the sludge outflow concentration. The boundary of the sediment was hotographed for evaluation. Based on the results of an overall evaluation, of the intake and outflow pipe lengths, we recommend a 2/3 take and 1/3 outflow pipe configuration without the use of baffles for separation tanks with a single-tank onfiguration.（After evaluation of the lengths of intake and outflow pipes, results suggested that a 2/3 intake o 1/3 outflow pipe ratio, without the use of baffles, was the optimal configuration for a single separation tank.）here a single tank is divied into two, a volume ratio of 0.5 in advection for the intake and outflow pipes was und to be optimal.
