The 17th Annual Municipal Green Building Conference and Expo (Innovative Cities Leading the Way to a Sustainable Future) was a big success this year. I had to park in overflow parking! https://usgbc-la.org/programs/mgbce
For people who were not able to attend–here are some of my favorite highlights from the Green Building Conference.
My favorite part was the water reuse training seminar. What a great chance to hear from building owners, contractors, vendors, and engineers about their experiences with water recycling. A much broader picture of the subject than one gets from reading the LID requirements. The building owners agreed that water reuse pays for itself now and that the cost of water saved can be impressive but the hidden cost of sewer impact will hopefully become more of a deciding factor in the future.
I found the handout helpful-it broke down the whole water reuse subject into four types. In order of complexity these are:
Tier 1: Rainwater and air conditioning condensate reuse. This water is allowed to go to toilets, laundry, and cooling tower makeup.
Tier 2: Graywater (using lavs(handwash sinks), showers, and laundry waste for subsurface irrigation). If the water is cleaned up a bit it can be also used for spray irrigation, fountains, and vehicle washing.
Tier 3: Stormwater reuse (this means the type of rainwater that has seen automobile traffic or industrial type things in anyway).
Tier 4: Recycled water. This means cleaning up the water waste from lavs/showers and rainwater and using it for more than just graywater uses.
The price per gallon of the various Tier systems varies with the complexity of the system and the size of the system. The amount of State involvement (code approvals, monitoring etc) also varies with the complexity of the system.
Deciding on a system is not so much a matter of first cost but a matter of matching the available sources of water to the available reuse. One has to compare the number of a building’s lavatories, air conditioning condensate, and roof area to the amount of landscaping, fountains, vehicle washing.
In my own experience-I estimate I was able to save one client 600,000 gallons of water per year with a simple low cost system. It felt good to add that to my blueprints.
I wish I had time to catch Nathaniel Wilson’s training seminar on Accessory Dwelling Units (ADU’s). Streamlining code approvals for home and building owners to build or remodel tiny apartments into their properties will have a positive impact on allowing people to live more easily near to where they work. I for one enjoy not having to commute in a car everyday 😉
Guy Van Meulebrouck PE consulting engineer 