Many communities worldwide are approaching, or have already reached, the limits of their available water supplies. Water demand exceeds sustainable supply in many areas and the current practices of diversion, consumption, use and disposal are depletive and destructive.
The New School University adopted a “water fit for purpose” strategy to address this challenge where all sources of water were considered and all opportunities to reduce water use were identified. Working with NSU, the New School installed conservation fixtures and an on-site water treatment and recycling system at The New University Center on 5th Avenue. The systems are designed to reduce water use by 74% and reduce discharge into the combined sewer by 89%. All wastewater (commonly referred to as “blackwater”) is collected and treated at The New University Center including water from toilets, sinks, showers, laundry, etc. Stormwater is also included as a source of reclaimed water after being detained by the vegetated green roofs The University Center contains one of the largest in-building water recycling systems in New York City at 40,000 gallons per day (gpd). The University Center is one of the first buildings approved to reuse treated water for laundry. Other uses include toilet flushing, irrigation of the green roof, cooling tower make-up and sidewalk maintenance. The University Center water resource management strategy including conservation fixtures and an in-building water treatment and recycling system contributed to all Water Efficiency LEED points and several within Sustainable Sites along with Innovation in Design
The below figure is a process schematic of The University Center water recycling system. It consists of a membrane bioreactor (MBR) followed by a multiple barrier approach for disinfection. The bioreactor is an activated sludge system with membranes that have an effective pore size of 0.4 microns. The disinfection system consists of an ozone generation and contacting system, used for oxidation and color removal; followed by an ultraviolet light system for additional disinfection. Effluent water quality meets strict reuse standards established by the NYC Department of Buildings, which are similar to the highest level reuse quality requirements established by many states.
Finished water in the storage tank is circulated through the ozone and UV systems to maintain the level of disinfection. Surplus raw wastewater and residual biosolids are discharged to the NYC sewer system. Automatic potable water fill valves at the water storage tanks ensure an uninterrupted supply of water. In this way, there is a backup system to provide water service even in the event that the recycling system is out of service for repair or maintenance. A computerized system automates control of the process including calling NSU operators when necessary.< back to case studies