Session: 12-02: Process Heat for Industrial Decarbonization

Paper Number: 157792

157792 - Solar Powered Distillation System in Dairy Effluent Treatment 

Abstract: 

Water is one of the key resources in the world, which is slowly becoming scarce due to the higher demand resulted from rapid increase in population accompanied with industrial and economic growth. The dairy sector is one of the largest wastewater-producing industries in the world. The dairy effluent is generated by processing dairy products. If the effluent from the processing facility is directly discharged into water bodies, it poses significant dangers to aquatic animals and plants, as it contains several chemicals and impurities.  Treating dairy effluent not only prevents water pollution but also contributes to generating drinking water. On the hand, the water treatment is energy intensive process which contributes to high energy consumption and CO2 emissions. To prevent this situation, the process of treating dairy wastewater can be carried out using a solar distillation system as an alternative. This not only minimizes the energy consumption but also reduces the carbon footprint. 
This paper presents an integration of a parabolic trough concentrating photovoltaic thermal (CPV/T) system with a dairy effluent treatment process, which generates both electricity and hot water. A Concentrated Photovoltaic Thermal (CPVT) system is a hybrid solar energy technology that generates electricity and thermal energy from sunlight. It combines solar photovoltaic (PV) technology, which converts sunlight into electricity, with solar thermal systems, which capture heat for various applications, enhancing overall energy efficiency. Excess heat generated by photovoltaic (PV) panels is recovered by circulating water beneath them. This process not only improves the overall efficiency of the PV system by cooling the panels but also creates a valuable by-product, heated water.
 
The dairy effluent treatment process includes several stages such as screening, chemical coagulation, dissolved air flotation and sequential batch reactor (SBR). Half of the effluent stream after SBR is directed to multi-effect distillation (MED) system and remaining is directed to the reverse osmosis (RO), followed by disinfection. The RO plant is powered by the electricity generated by the electrical output of CPV/T system. A plate heat exchanger is used to preheat the effluent, increasing its temperature from 25°C to 75°C before entering the MED. The hot fluid in the exchanger is sourced from the CPV/T system. The proposed CPV/T system was modelled using TRNSYS software to simulate the electrical and thermal outputs.
The proposed solar powered effluent treatment plant was designed to treat 360 m3 per day estimated to be generated by a small-scale dairy manufacturing company producing various dairy products located in Dubai in United Arab Emirates (UAE). The United Arab Emirates (UAE) has a substantial potential for solar energy, receiving an impressive average of 3,568 sunlight hours each year. This translates to about 9.7 hours of sunlight per day. As a result, the country experiences an average annual solar radiation of approximately 6.3 kilowatt-hours per square meter each day. This abundant solar resource makes the UAE an ideal location for solar energy generation.The capacity of the CPV/T module, which represents the electrical and thermal energy outputs supplied to the RO and MED plant was determined using TRNSYS software and according to the available solar radiation levels in Dubai. 
The obtained results showed that integrating a concentrated photovoltaic thermal system with the dairy effluent treatment process is a crucial step in promoting sustainability and reducing the carbon footprint of the overall system.
 

Presenting Author: Fadi Ghaith Heriot Watt University Dubai Campus

Presenting Author Biography: To be provided later