(Notes by Joel)
John Scarpulla talked to us September 18th, 2014, about the Living Machine at the Public Utilities Commission (PUC) building SF Headquarters. John is a project manager, not an engineer. Very informative.
PUC headquarters: a well built building. Safe place in a quake. Command center for emergency operations. Features: Rainwater harvesting in preschool play area made of spongey material that’s permeable. Collects the water there and uses it to irrigate street trees.
The system called the Living Machine, a million and a half gallons per year. Not a large project compared to the 65 million gallons per **day** that the SF sewage treatment plants treat, but an example, a demonstration site. And a chance to test processes, including permits and ordinances. Wastewater treatment out in the open. Integrate technology into the neighborhood providing green in tenderloin.
Building is separately “dual plumbed” for potable water from the Hetch Hetchy system and wastewater internal system.
Water flows from primary tank to flow equalization tank to wetlands to building in a 48 hour loop. Flows from 7 to 7; none at night or weekend. Wetlands are in sidewalk, lobby and then the water cycles through the basement systerms.
Primary treatment tank is called and looks like a big “hotdog” and they needed a permit for that because it goes under the sidewalk.
First, a trash chamber separates things that shouldn’t have been flushed.
Second, a settling chamber removes a lot of the settleable and floatable solids. The solids are processed elsewhere. They don’t manage solids on site because the site’s too small.
The cycle is in waves, sending batches into the system with a 3000 gallon equalization tank. Recirculating tank for water available to go back to toilets is 6000 gallons. Wastewater treatment of 5000 gallons a day.
Nature wetlands, etc. process water by slowing the flow and cleaning the water but this speeds it up while cleaning it.
One way they do that is with “tidal” action. Water fills and then goes down like a tide every 58 minutes. Process quickly because the plant roots and soils are exposed to an influx of oxygen when water is low and organic microorganisms when the water is up. Most of the solids that were suspended in the water are removed by this process. Both aerobic and anaerobic bacteria involved. Self sustaining.
Ramped up population at the beginning, two years ago: Plants got inoculated then synthetic wastewater (milk solids and ammonia) were fed to it until real nutrients came into the system when building opened. Gradually reducing synthetic wastewater as human use increased so microorganisms kept stabilized.
Off gassing of nitrogen tells what population of microorganisms is like.
Department of Public Health (DPH) required wastewater to stay six inches below topsoil, so there are overflow vents to the sewer system preventing sidewalk overflows. Four inches under there’s a mesh to keep people from digging into the wastewater. No odors because subsurface vent sucks in and odors are emitted through a rooftop carbon filter scrubber.
Reasons particular plants were picked: Marsh plants can stand water in their roots all day every day. Must be tolerant of high nutrient levels. North side gets no sun. Plants have to be able to survive those conditions.
Landscape architect new to this but experienced engineer that has done this system before.
Batch sizes depend on whether it’s raining and day of the week. People are not in the building weekends.
Golden Gate Avenue side is the tidal flow wetland. Polk is the vertical flow wetland: one pass through of the water there first to cell 2a, then down hill to cell 2b. Light tan tint to the water after going through the wetlands. The filtering is then complete so it goes into the interior lobby plants which are a different plant pallet with species that like more sun.
“Acre Café” is in the lobby area twenty feet from the treatment.
There are pumps in addition to gravity. Twenty percent of California’s electrical and 30 percent of natural gas in the state is used for water systems. Living machine uses 75 to 90 percent less power than other systems available because they all use force through a membrane and this does not.
The water gets disinfected with UV light and a little chlorine in tablet form like a pool before it goes to the toilets again. There is one building in Toronto trying something similar that decided not to do chemical treatment and the mold growth became a public health and operational concern.
The system is entirely operated by computer from control room or from desktop computer or smartphone. Fully automated.
Aqua Nova specializes in wetlands.
DPW (Public Works) was involved because it was a large public building being built. Permits: No regulatory rules existed for this so they had to create some. DPH and DBI (Department of Building Inspection) and PUC signed letter of agreement. Will test yearly and inspect plus send results to DPH. Choloform, Turbidity, Oxygen load, etc. In the system itself, sampling is the biggest time draw. Otherwise little for humans to do to maintain it, oh except: Maintenance is big because warmth attracts sleeping, then there’s vandalism. People steal the plants and they have to be replaced.
Inreach wasn’t done as well as they wanted. For an agency of 2300 only about a dozen people came to the one inreach meeting. Outreach was good though.
Project purpose: help ask How can we get other building designers to rethink? In large residential, about half is nonpotable. 95 % in commercial buildings.
City ordinance introduced: Now any building in SF can reuse blackwater, graywater, stormwater (hits ground), rainwater (hits roof), or groundwater.
Amended an ordinance: Buildings can now share non-potable water between them but only by contract, whether paid or free.
If you go into the sidewalk you need a “minor encroachment” permit and it street then “major encroachment” permit.
PUC’s nonpotable guidebook is available from John. Grants from PUC are available for certain sized buildings to encourage development of more such systems or similar. If you expect to offset enough per year you get the grant.Moscone and Transbay and others will use from groundwater systems on sumps. Sump water doesn’t need all the plant cycle stuff, just filter and UV.
The Bullet Center and two military systems in San Diego are using black water, otherwise most systems that exist now are sump (groundwater) or storm water.
John Todd is the inventor of the living machine and calls himself an ecological engineer.
AAA Clifornia Automobile Association building had a groundwater system but was a failure due to high iron in the water. (Different locations have different minerals in groundwater.) gave them orange toilet stains so they only operated it a month. Redid building and took the system out.
In PUC building graywater and blackwater both treated combined, so it all is called black water.
Gray water reuse for homes was allowed as of last year by state law changes. Became okay for using indoors in January 2014.
Airport has a hidden and fenced-in staff building that does the same full system for blackwater but only 475 people work there.
Solar panels produce 12 percent of the buildings energy and the wind turbines 1.5 percent so easily covers the system pumps and UV.