'Crush' season was a challenge for this California vineyard, creating severe wastewater treatment problems. Biological oxygen demand (BOD) loadings peaked at excessive amounts. Without effective treatment, the odor from the wastewater could be conservatively described as 'objectionable'. But, finding effective treatment was difficult due to its shallow 3.5 ft (1.07m) deep ponds. The ponds had been originally designed as evaporation ponds. However, the peak 'crush' season proved they did not work effectively.
The winery decided to try the AIRE-O2® system, starting with six units originally. When the next 'crush' season started, the winery had nine AIRE-O2® aerators totaling 31 hp (23 kW) installed. The units varied in sizes from one, two and three hp (.75 kW, 1.5 kW and 2.2 kW). By adding the one x 1 hp (0.75 kW) unit to treat the high strength influent, the supervisor transformed a tank into a pre-treatment chamber. That boosted the dissolved oxygen levels to 6 PPM before the 0.014 MGD (53 m 3) flow entered the five-pond system. Then, he skillfully positioned all the units to maximize the flow in each pond and adjusted the angle of operation to accommodate the shallow depths.
The influent BOD level of 1660 mg/l is obtaining excellent removal rates. By controlling the water movement, 'hydrostatic baffling' eliminates short-circuiting and ensures optimum treatment efficiency. This grape growing and wine making region has a rich heritage, dating back 300 years to the earliest California missions. The supervisor is happy to keep that tradition intact. He says, 'the smell is better and the water is cleaner these days.'