Probability analysis of water quality by turbidity

Abstract

The distribution of turbidity values in given sample is analyzed. The results demonstrated that the nature of the distribution of turbidity values during the year largely depends on the seasonal factor, hence the analysis of the distribution of turbidity is performed separately for each month. Order statistic (variation series) is computed and an empirical distribution function of turbidity values is derived. It is concluded, that the distribution of turbidity in given water sample differs from normal, log-normal and gamma distributions. However, it can be described with sufficient accuracy by a cubic polynomial function. The turbidity distribution hypothesis is tested by the Kolmogorov–Smirnov test. The water turbidity distribution function predicts the probability of exceeding the specified values of turbidity and enables numerical assessment of its likelihood.

Prediction of optimal coagulant and flocculant dosage for water treatment at surface water intake

“…We have selected the specific periods when the water quality of the source water is different, taking into account the probabilities of indicators in question exceeding of the standards and maximum allowable concentrations (MAC) (calculated using the gamma distribution) [16][17]. The probability of exceeding the standards by the indicator is higher the closer the probabilities are to 0.…”

“…Thus, calculation and adjustment of the correct dosage of the aforementioned chemicals presents a major issue in water treatment processes and is often carried out manually based on current water sample analysis and running tests. This, in turn, contributes to changes in water samples composition, sample contamination and certain indices rising [7][8][9][10][11][12][13][14][15][16][17]; this may result in violation of hygienic requirements and drinking water quality standards, in terms of turbidity, color, oxidizability and general hardness [18]. Therefore, it is necessary to thoroughly study the multifactorial dependences of the chemical agent dosage on water quality indicators.…”