Study on Characteristic Extraction of Variability Components and Inflow Fluctuation through Application of the State Space Model on Daily Inflow Rate of Wastewater of Rural Sewerage Facilities

Abstract

Variability components of daily inflow rate of wastewater were examined through application of the state space model, and variability characteristics were considered for actual rural sewerage facilities. The daily inflow rate of wastewater was separated into (a) the trend component, (b) the seasonal change component, (c) the weekly change component, and (d) the precipitation-corresponding component. These components were well correlated with influent quantity. The value predicted by the state space model well explained actual inflow discharge data. The daily inflow rate of wastewater was associated with (i) influent quantity that corresponding with the population in a basin, (ii) the dynamics of population in a basin, (iii) the amount of precipitation, and (iv) events such as summer or new year holidays. The analysis using the state space model has a few remained issues on prediction precision of the precipitation-corresponding component and interpretations of the seasonal change mechanism. However, this analysis is effective for characteristic extraction of variability components of daily inflow rate of wastewater on actual rural sewerage facilities.