Stormwater purification through progressive freeze concentration: effect of coolant temperature and operation time

The scarcity of clean water due to industrialization, the growth of the population, urbanization and the climate changes was becoming a concern for the world. There are several methods that were usually used to purify water by the industries such as reverse osmosis (RO) and evaporation. However, these methods have several flaws and Progressive Freeze Concentration (PFC) was introduced as a better method. In previous researches, it stated that PFC has low energy consumption compared to evaporation method. It also has lower capital cost and maintenance fees compared to reverse osmosis. Therefore, PFC was introduced in this research as an alternative method to purify the stormwater The objectives of this research were to investigate the effect of operation time on K value and water recovery and to study the effect of coolant temperature on K value and water recovery. The experiment was conducted with simulated stormwater as raw material. Coolant bath, stirrer, motor and crystallizer were gathered to form the PFC system. The experiment was conducted by varying the studied operating condition such as coolant temperature and operation time while other operating conditions such as initial concentration and speed rotation were kept constant. The required data were measured, collected and calculated for evaluation of K value, water recovery and efficiency. As the result, it was found that the best operation time is at 20 minutes with K value, water recovery percentage and the efficiency percentage of 0.1329, 23.8% and 88.27%, respectively. Meanwhile, the best coolant temperature is -10°C with of K value, water recovery percentage and the efficiency percentage of 0.1829, 34.7% and 88.3% respectively