Reverse Osmosis (RO) is a key component of the DPR treatment process. A significant challenge for this process is developing a safe and effective strategy for the disposal of reverse osmosis concentrate (ROC), the byproduct of RO purification. ROC contains the same contaminants as typical treated wastewater but at a much higher concentration (approximately six times greater). Due to this high concentration, directly discharging ROC through existing effluent outfalls without additional treatment poses regulatory and environmental challenges, particularly in the Lower South Bay, where mixing and dilution are limited.
Conventional ROC treatment methods are often expensive and energy-intensive, which has led to an increasing interest in nature-based solutions (NBS) as a more sustainable and multi-benefit alternative for ROC treatment.
Valley Water has been actively investigating NBS as a sustainable approach to managing ROC. NBS utilizes natural processes to reduce contaminants while also providing co-benefits such as habitat creation and flood protection and consequently assist with meeting the regulatory requirements and protecting the health of San Francisco Bay. Valley Water is actively exploring NBS as a viable, eco-friendly approach for managing ROC.