Although considerable attention is drawn to the 1 percent of the world’s available water supply that is used for drinking, the vast majority of our water is used for agriculture, commercial and industrial purposes and this finite resource is rapidly depleting. Municipalities, businesses, and schools, particularly in the more arid regions, demand systems that not only fulfill day-to-day water needs, but also must simultaneously conserve water in a cost-effective manner. This is indeed a challenge, particularly given the nation’s aging and inefficient infrastructure and increasingly strained water supplies.
NSU specializes in taking an integrated water management approach when developing the solution and seeks to optimize water and energy usage at each and every project site.
We manage the design, construction, and operations of several wastewater reuse systems that are helping to lead a transformation of water infrastructure within the United States, some of which recycle 100% of the wastewater treated. Direct water reuse is a beneficial and innovative approach where wastewater and stormwater are treated and reused for multiple non-potable purposes, greatly reducing demands on fresh water supplies:
- toilet flushing
- cooling tower make-up
- landscape or rooftop irrigation
All of the water reuse projects designed by NSU incorporate blackwater (typically water from toilets and urinals) and greywater (typically water from all drains except toilets and urinals) treatment systems. In addition, NSU offers services in rainwater harvesting or stormwater management using green stormwater infrastructure.
NSU’s direct water reuse systems are of varying capacities and sizes depending on the particular needs and water demand for each building. Each system employs the same basic technology:
- Anoxic and aerobic treatment is employed to remove the biological oxygen demand and nitrogen to comply with each states direct reuse standards.
- Filtration is typically applied. In several of the systems, submerged microfiltration membranes are in place to remove suspended solid particles. This treated, filtered water is then passed through an ultraviolet light system that kills pathogenic bacteria.
- Disinfection using ozone can be used to completely remove any traces of color.