1991 Fiscal Year Final Research Report Summary
Study on Application of Reactors Using Suspended Biological Flocs with Small Size Media for Municipal Wastewater Treatment
Grant-in-Aid for General Scientific Research (C)
|Allocation Type||Single-year Grants |
|Research Institution||Tokyo University of Science |
KASHIWAYA Mamoru Science University of Tokoy Civil Eng. Professor, 理工学部, 教授 (80152643)
DEGUCHI Hiroshi Science Univ. of Tokyo Civil Eng. Research Associate, 理工学部, 助手 (70207504)
|Project Period (FY)
1989 – 1990
|Keywords||small size media / glass beads / anaerobic-anoxic-oxic process / mixing intensity / cell model|
Some laboratory tests have been carried out to remove organic carbon, nitrogen and phosphorus compounds simulataneously from municipal wastewater by Anaerobic-Anoxic-Oxic (A_2O) process.
At the test, overall biomass concentrations in reactors were maintained in a range of 6 to 10g・1^<-1>, and suspended biological flocs with small size media (glass beads) consisting of both 0.1mm and 0.05mm in diameter were grown to maintain such higher biomass concentration continuously in the reactors.
Wastewater to supply to the reactors was set up cases of timely varied load feed as well as a case of constant load feed taking into account of the application of small-flow wastewater treatment facilities.
A cell model composed of a large number of small compartments was applied for the reactor design analyses. As a result, it was found that sizes of suspended biological flocs with glass beads were expressed as a function of mixing intensity of mixed liquor in the reactors. And, it was also confirmed that
a piece of biological flow was built up from a piece of 0.1mm in diameter glass beads, while from seven to eleven pieces in the case of 0.05mm in diameter glass beads.
From the mathematical analyses applying cell model to the reactors, both equations were proposed to calculate the rates of nitrogen and phosphorus removals in wastewater. These equations could express as the functions consisting of the products of BOD volumetric loading, biomass concentration and detentiontime in the reactors.
The coefficients and constants in the equation were determined the data obtained from laboratory tests. And, the proposed equations were confirmed the accuracy by using both data obtained from laboratory and field tests. The calculation results by the proposed equation for the rate of nitrogen removal were nearly coincided with the laboratory test data except the results of nitrate liquor recirculation ratio of 1.0 and 1.4 which were extremely fluctuated test data. The calculation results by the proposed equation for the rate of phosphorus removal were almost coincided with laboratory test data. The calculation results by above proposed equations were given 15 to 25% lower than field test data on the rate of nitrogen removal and 10 to 20% lower than same test data on the rate of phosphorus removal. Less
Research Products (2results)