I. Introduction
River water quality monitoring (WQM) is a timevariability, uncertainty, and a highly non-linear problem. It has two parts, namely observed states and an online measuring state. Internet of Things (IoT) based WQM has been proposed by Hanifah and Supangkat; different sensors (turbidity sensor, rain sensor, flow sensor, salinity sensor, temperature sensors, and pH sensors) have been interfaced with a controller and k-mean clustering has been used for data classification. A comparison study has been done and the result shows the superiority of the method [1]. To recognize the location of WQM stations in the river system is proposed by Ilker et al. Water contamination has a significant impact on how different water parameters are calculated. Four most water pollutant includes trash, parasites, bacteria, and chemicals [2]. Large amount of domestic and industrial waste water is delivered to the river. The sewage system and the wastewater treatment facility comprise an interconnected wastewater system. Non-linear model is used for the biological process. WQM was done using soft measurement based on interval observer and it can give accurate estimation [3].