First Grey Water Irrigation System: Lessons
Wednesday, December 2, 2009 at 3:17PM Gray Water Irrigation System
In order to accommodate Abode Communities request to explore water saving measures for landscape irrigation, Khalifeh & Associates Inc. set out to design the first gray water system approved by the County of Los Angeles.
At a time when Los Angeles is facing water shortages, Abode Communities (a non-profit developer specializing in sustainable low-income housing projects) was committed to invest the necessary resources for designing and installing an environmentally sound system that would reduce water consumption in their 70 unit senior housing project.
Khalifeh & Associates explored different ways to meet this challenge and 
found that the best way to reduce consumption would be to retain, filter, and reuse the discharged water from the project’s onsite laundry facility. The effluent released from the washing machines would be captured in a 750 gallon underground storage tank located nearby the Laundry room. Contractors bid this system to have an installed cost of $60,000 and project that landscape water consumption to be reduced by 90%, giving the system a 25 year payback. The water factors of standard front load clothes washers are 31.5 gallons per cycle, 1 hour cycle time, and there are a total of 7 washers installed onsite. The laundry facility operates 12 hours per day, making its’ water usage 2,646 gallons/day.
31.5 gallons per wash x 1hr cycle x 7 washing machines x 12 hour occupancy = 2,646 gallons per day
100% of the effluent released by the washing machines will be captured in an underground storage tank equipped with a small irrigation pump. The effluent from the washing machines require sufficient filtration and treatment before landscape application is done. Dependant on the type of soil, local codes require respective minimum square footage of irrigation area per 100 gallons of estimated daily gray water dispersal. The Soil sample taken by a Geotechnical engineer proved the soil to be in a category requiring 100ft² of landscape area per 100 gallons of gray water. This made the total required area 2,646ft².
2,646 gallons x 100ft² ÷ 100gallons = 2,646ft² of required landscape area
The actual total irrigation field onsite is just less than 10,000ft² which is considerably larger than the minimum required area per code. With this information along with plumbing system design drawings and additional calculations, Khalifeh & Associates sought to have their water saving system approved by the Los Angeles County Building and Safety plancheck department. Such a system had never been approved and thus review of the Khalifeh & Associates proposal was extremely thorough. The county wanted to know, without a doubt, that the system would function properly and that well thought out safety measures would be incorporated to address the possibility of system failure.
After several attempts to obtain the county’s approval, the engineers at Khalifeh & Associates were able to convince the plancheck department that all of the county’s stringent requirements would be satisfied. Their approval makes the team at Khalifeh & Associates the first consulting engineers to design an approved gray water system in the county of Los Angeles for reducing water consumption and improving the environment.
Jack Khalifeh is president of Khalifeh & Associates Inc. Consulting Engineers, P.E., a multidisciplined, professional engineering firm specializing in mechanical, electrical, plumbing, fire protection, lighting, sustainable design, commissioning and energy audit services. Jack is a LEED-accredited professional and a member of the U.S. Green Building Council. Visit www.khalifehassociates.com tel:(310)-305-1555
Reader Comments (30)
I think that's a good step. Now we need a smaller, much less expensive version for single family homes.
Posted by Jim Anderson
Very interesting approach (especially what they had to go through to get it OKd), thanks for sharing. If you want to have less hassles and still use your grey water and cut down on your water bills, you might want to look into Brac Systems (use your grey for flushing the toilets) http://www.bracsystems.com/
Posted by Lee Schnaiberg
Sounds great, but I am not sure if this was on new construction of these apartments, or a retrofit for an existing occupied building. As Director of Asset Management at EBALDC in Oakland, this distinction is extremely important. Please clarify.
The most surprising thing about this story is that it has taken LA County until 2009 to sanction a gray water system. As a former CA resident for many years, I enjoyed the state's generally forward-thinking attitude and planning with respect to conservation and the environment. This johnny-come-lately project approval (it can't be the first attempted project approval-- can it??) is certainly better late than never, and opens the door to a new and vital world of water savings; the West is going dry and yesterday's the time to prepare for greater water efficiency.
I noticed the rather generous calculations for system capacity, based on maximum possible usage of the laundry facilities. Surely the residents of this housing project do not run the washing machines all (half-)day, every day, in back-to-back cycles! I assume this outrageous usage assumption was required by the county planning dept. Guess where there's progress yet to be made? In our outdated, uber-cautious (read: litigation-neurotic) bureaucracies, such as planning and code-checking depts. Well, two steps forward...
It is about time that a major city planning & conservation department sees the light regarding water conservation. Being that fresh water will soon be the new "God", as if it is not already in California, we need to embrass this type of re-use.
Two Things: First, the graywater system used here was designed by Steve Bilson of ReWater in San Deigo.
Secondly, after a momentary glimpse at easing our way to graywater reuse in CA, we are now taking a step backwards again. Rather than passing the almost progressive rewrite of the CA Uniform Plumbing Code, Chpt. 16, Part A, which took a small step forward by allowing unpermitted graywater systems in residences using under 250 g water/day (single source systems), HCD is bending to pressure by those not involved in the rewrite process to now again require all graywater systems be permitted.
Given that there are an estimated 1 million graywater systems in CA, and only 8 or so are permitted, this is a terrible step backwards to the musty dark ages from which we were just starting to emerge.
Take head. Insert firmly into sand (cause there ain't gonna be no more water).
Or SAY SOMETHING! dhensel (at) hcd.ca.gov
This is an amazing achievement. Reaping back the cost of water in 25 years sounds like it might be a hard sell, but emerging technology and methods to share important facilities such as this new grey water system are just only now appearing on the landscape. It wouldn't surprise me to learn that the payback was dramatically escalated when LA County was forced to raise water costs, and this lucky investor dodged a mighty bullet. Bravo, and thanks for the post.
Posted by Robin Basham, M.Ed, M.IT, CISA, CGEIT
This is great, i find we suffer more from hesitation on the part of building departments when there is technology and concepts that don't always fit in to the current thinking. Yes I know they have to protect the public from themselves, but this is a great start.
Posted by Bruce Goff
Wow! not just 'reclaimed' water but Grey Water! I am familiar with leech fields that are used in conjunction with septic tanks but that is small scale. We do have an aquifer here and I suppose using it as a filtration system for agriculture is fine as long as food isn't grown with it.
Posted by Steven A. Davis
I would also suggest people look at www.reusegraywater.com to see the newest and most sophisticated water recycling system approved in the City of Los Angeles. It is far and away the most technologically advanced system for recycling gray water that has been approved for residential and business use. It is already up and running at a number of Los Angeles locations and was recently featured on the TV series LIVING WITH ED starring Ed Begley, Jr.
Posted by Greg Glass
Good initiative.Why only grey water and why not with beneficial Micobes and Nutrients added to Irrigation water !
Posted by Lokesh Punj
This is great news. I am also interested in the regulatory path of this permit. Who is actually providing the permit in LA? Is it the Health Department, the Building Department?
Posted by Laurie Schoeman
Very interesting. 25 year payback though...Also, I wish they would have been more detailed as to the actual system. I am curious about the filtration and how it filters regular detergent to make it safe for plants and grass.
Posted by Anna Hackman
The 25 year payback seems to refer to just the cost of reducing city water. I am wondering if the sewer discharge rate is, or can reduced by diverting it from the LA water treatment system?
November 14, 2008
Commonwealth of Massachusetts awards BRAC approval
After a thorough review, the Board of Examiners of Plumbers and Gasfitters for the Commonwealth of Massachusetts has approved both the residential and commercial product line of Brac Greywater Recycling Systems. The meeting was held on November 5, 2008 where the Board voted and granted approval to install our products in their State.
Brac Systems had been working with a local architectural firm to secure an approval for the installation of a residential unit in the City of Cambridge, Mass. Now that the Brac System has been approved, the installation will proceed as planned and will mark the first of many installations to come.
Brac Systems has also just received product certification by IAPMO R&T for the new commercial system sizes. See the new Commercial Page for more details.
http://www.bracsystems.com/products.php?id=16&action=view_prod
Posted by Jeffrey Geibel, APR LEED AP
Thank you for sharing this information. This sounds like a great system. I think this type of system is very relevant for private houses as well as multiple housing, described in the blog. My irrigation system drains my well in the summer, so I've stopped using it and hope for lots of summer rain.
Posted by Sheri Koones
Hello Grant. We connected recently and as such I noted your grey water discussion post. I have some experience with commercial building wastewater treatment and reuse technology going back to the 80s that I thought might interest you.
Technology was developed and successfully marketed by Thetford Systems for some years before company was purchased by Zenon, who was then swallowed by a bigger fish, GE Water. See link below FYI.
http://www.gewater.com/industries/green_building/index.jsp
Regards,
Carl
The system is not particularly well described, nor was the process or considerations for its design or approval. This is primarily a sales piece.
Posted by Dana Marshall
Seems pretty expensive and a long - 25 year - payback. I don't think it will be easy to convince clients to go this route without some public subsidy, especially in this economy.
Posted by James Strozier, AICP
Me too. There are lots of discussions on the net about grey water systems, but they are generally for loosely regulated, often rural (dare I say it: hippie) installations. I am sincerely curious about how the big city engineers responded, and what new rules they came up with on matters like sizing, design of filtration systems and controls thereof, source limitations (washers by not showers?), pump controls, overflow design, venting, and a long list of other issues.
Posted by Dana Marshall
It may not be easy to convince anyone, but the concept/fact of heliocentricity took quite some time as well. This may be the step we need to finally start breaking through renewable "energy" sources in the greater market. From what I've seen and heard so far, it's a great options for residential housing; why not public facilities?
Posted by David Dudis
Congratulations! I hope that in the US there are other examples of grey piping!
Posted by Agostinho Miguel Garcia
Yes, this is indeed a greywater system - water from interior plumbing wastewater, excluding toilets and other sources of fecal matter. Too often it seems the term"greywater" is applied to stormwater systems. That's relatively easy, this type of true greywater irrigation is harder as the article points out. I suspect it is pretty rare too, in spite of many references to its benefits.
750 gallons is not a large capacity, but the price was relatively high.
Posted by Dean Sherwin
How was the extra cost of the system financed by the non-profit developer? Were there any incentives? Was the overall project a tax credit project? Do you have a contact for the developer's project manager? I'm a project manager for an affordable housing non-profit.
Posted by Susan Moffat
Your article is really informative. I will surely bookmark it for future reference. Good work! Keep it up. It has been a long time since I have heard somebody about this topic. I will surely bookmark it for future reference. Good work! Keep it up.