Abstract
A Zero Liquid Discharge (ZLD) system is an industrial wastewater treatment system used to eliminate liquid discharge leaving an electrical generating facility. A typical ZLD treatment process separates water from the industrial wastewater stream, concentrating the suspended and dissolved solid wastes. Prior to implementation of ZLD systems, the liquid wastewater stream was discharged directly to the environment. In a typical ZLD system, the equipment used to operate the system is powered by electrical sources of energy within the electrical generating facility. The operation of equipment in a typical ZLD system results in a parasitic loss for the electrical generating facility. This thesis theoretically proved that a proposed alternative ZLD system configuration can operate more efficiently than the typical ZLD system configuration, without jeopardizing the quality and integrity of the overall process goal. Quantification of the typical ZLD system was based on measured data from an operating typical ZLD system and calculated performance of the system. Estimated performance of the proposed ZLD system and a comparison of performance between the typical and proposed ZLD systems are included. The proposed ZLD system utilizes a steam ejector and supply steam as an alternative to the rotary lobe compressor and electric heaters within the typical ZLD system. The proposed ZLD system consumes 35.9% of the designed typical ZLD system electrical consumption for steady state operation and 20.3% for start-up operation. The proposed ZLD system matches the measured typical ZLD system processing capacity with an electric power consumption reduction of 161.13 KW for steady state operation and a reduction of 353.52 KW for start-up operation. The proposed ZLD system produces 78.32 BTU/s of available thermal power more than the typical ZLD system. The mass flow rate of distillate water for the influent wastewater heat exchangers in the proposed ZLD system doubled when compared to the typical ZLD system. All other thermal power consumptions within the typical ZLD system were maintained in the proposed ZLD system. The overall process goal of treating industrial wastewater and eliminating a liquid discharge to the environment in the typical ZLD system is met by the proposed ZLD system with higher electromechanical efficiency. Additionally, a brief discussion on the feasibility of implementing the proposed ZLD system is included.