Enhanced Energy Saving in Wastewater Treatment Plant using Dissolved Oxygen Control and Hydrocyclone

Abstract

Abstract Water and energy are precious commodities. With the rising population, their demand is escalating day by day. If we talk about water, groundwater is the primary freshwater source for private colonies, apartments and institutions in India. The present media reports forecast that 21 Indian cities will be running out of groundwater by 2020. Reuse of treated water from wastewater treatment for non-domestic applications is one of the best alternatives to control the scarcity of fresh water. The conventional Wastewater Treatment Plants (WWTPs) have limited capacity and are energy-intensive. The existing WWTP of the LNM Institute of Information Technology (LNMIIT) is retrofitted to achieve the required capacity and quality for reuse. In this paper, some of the novel techniques like hydrocyclone and smart aeration control have been adopted for energy saving per unit of wastewater treated. Hydrocyclone was designed and installed for primary sludge separation. The air supplied in the bioreactor was controlled through the smart aeration control system consisting of Variable Frequency Drive (VFD), Dissolved Oxygen (DO) sensor and Programmable Logic Controller (PLC). Under this process, the installation of VFD enhanced the power factor by 17.15%, thus creating energy saving of 17.49%. The DO control with VFD in the bioreactor reduced the electrical energy consumption for aeration by 66.75%. The installation of hydrocyclone as a primary sludge separator with DO control saved the electrical energy for aeration by 71.46%. The developed system provided stable operation with enhanced aeration energy efficiency and treatment capacity.