Water reuse for the bottled water industry

Abstract

The bottled water industry uses a machine specifically designed for the washing of its containers (19-L capacity) and generates 6-L wastewater/container. This effluent can be used for watering of green areas and car washing. The objectives of the present work were to characterize the effluent and to propose a specific treatment to enable reuse of the effluent from the container washing machine. The analysis of water quality identified the following problems: high pH (10.0), high biochemical oxygen demand (50 mg/L), high concentration of free residual chlorine (3.15 mg/l), alkalinity (207 mg/l as CaCO3) and hardness (38.8 mg/l as CaCO3). These parameters must be reduced in order to comply with the Mexican standards for water reuse (NOM-003-ECOL-1997), and to protect the washing equipment against corrosion and incrustations. The water can be used for the watering of green areas after pH adjustment and Biological Oxygen Demand (BOD5) removal. If special equipment is used for car washing, it is necessary to reduce the concentration of calcium and magnesium using a strong cationic resin. Following these recommendations the specific industry installed a treatment system with pH adjustment, dual filtration (sand-anthracite) and adsorption system with activated carbon. The effluent is now used for watering of green areas and for car washing with garden hoses.