A Low Cost Wastewater Reclamation Unit comprising a Lamella Settler for reducing Fresh Water Usage in Carwash Stations

A low-cost carwash wastewater reclamation unit comprising a lamella settler and filtration unit was designed and fabricated in the laboratory. A newly designed lamella settler, Reflux Lamella Settler (RLS), consisting of two inclined sections, was incorporated for the first time in the reclamation unit with the objective of enhancing the sedimentation process. Furthermore, organoclay was employed as a component of the filtration unit to remove oil contents. The analysis of the reclaimed water demonstrated a notable reduction in the Total Suspended Solids (TSS), from 821 mg/L to 98 mg/L, in turbidity from 253 Nephelometric Turbidity units (NTU) to 2.70 NTU, and in the oil content from 26 mg/L to zero. This implies a substantial removal of the above substances of 88%, 98.9%, and 100%, respectively. Similarly, the concentration of hardness was reduced by 62.8%, from 321.6 to 120 mg/L, that of Chemical Oxygen Demand (COD) by 65.3%, from 274 mg/L to 95 mg/L, that of total solids by 65%, from 1590 mg/L to 543 mg/L, and that of total dissolved solids by 47.9%, from 769 mg/L to 400 mg/L. These results indicate that the reclaimed water was suitable for car washing. Moreover, a study on the RLS demonstrated a reduction in turbidity from 253 NTU to 175 NTU, 150 NTU, 130 NTU, and 10 NTU, respectively, after 0.5, 1, 1.5, and 24 hours. The RLS is an effective method for the removal of solid particles/sludge as a primary treatment step in carwash reclamation.