(702d) Development of a Modular Shipboard Wastewater Reuse System

Wastewater disposal in the shipping industry is an ever increasing problem as global regulations become stricter, limiting what can be dumped overboard and where it can discharged. Mainstream Engineering has developed a modular, innovative wastewater processing system that can treat both greywater and blackwater to produce a non-potable, reusable water stream and reduce the amount of water wastes that must be held by over 85%. One of the main drivers is the International Convention for the Prevention of Pollution from Ships (MARPOL) regulations which dictate the level of biological oxygen demand, total suspended solids, pH, coliforms, nitrogen, phosphorus, and chlorine are allowed to be discharged. Current marine sanitation devices (MSDs) and advanced water treatment (AWT) systems are large, bulky, expensive, or are unable to meet the necessary requirements of treating the 40 – 120 gallons/day/person generated on commercial vessels. Due to ever increasing disposal fees, there is a clear need for ships to reduce waste water generation not just for environmental reasons but also economic ones.

Shipboard wastewater is difficult to purify as it includes dishwashing, showering, bathing, laundry, all with their associated cleaning products and contamination. This is a particularly challenging feed due to the high concentration of surfactants (soaps), nitrogen, and solids that must be removed. Many traditional processes are slow, require significant space, or are sensitive to high swings in pH associated with strong acids (toilet cleaner) or strong bases (detergent). We have developed and investigated the use of a novel processing scheme to treat this water without any pretreatment or post-chemical usage focused around purely physical separations. We will present on the wastewater characterization, a variety of membrane/material effectiveness (e.g., PVDF, PAN) and fouling rates, process waste and energy efficiency, and overall system performance and economics with a focus on different control schemes and process models to mitigate long-term degradation.