# Analysis of Residuals for the Elimination of total Suspended Solids Simulation of wastewater through Rotating Biological Contactor

### Abstract

Increased attention towards substitute water resources has become unavoidable, as the world’s freshwater supply becomes gradually scarcer. Reuse of Greywater is a hopeful alternative water source for non-potable uses, which could be exploited on a continuous basis and treated. Getting average removal% of Total Suspended Solids from greywater through Rotating Biological Contactor following experiment was conducted to evaluate the significance Hydraulic Retention Time with numbers of discs. Consequences reveal that linear as well as quadratic estimate of HRT and number of discs have are highly significant effect as their corresponding p-values are even less than 0.01.By using coefficients of the table the regression equation is Removal = Removal% = -26.74 + 20.14 Time + 1.253 Disc, where the sample standard deviation is 4.82. Lack of fit of the equation is insignificant i.e. 0.155, which implies that the regression equation is fit for prediction. The probability plot of the residuals is roughly straight which demonstrate that errors distributions are around normal. Furthermore, Residual plot shows the linearity assumption appear to be met with constant standard deviations. Histogram of Residuals make obvious normality assumptions as the plot resembles an example of a sample from a normal distribution centered at zero and normally and independently distributed NID (0, σ2) assumptions on errors are accomplished as standardized residuals are approximately normal with mean zero and unit variance.