Hello,
I would like to get confirmation on whether the following approach of demonstrating compliance with LEED requirements could be accepted or not. We are only applying for credit SSc6.2.
In our building, we have designed ONE retention tank collecting water from roof and landscaping areas around the building. There are 2 different inlets to the tank, one for rainwater from roof and one for the rainwater from landscaped areas.
We have planned to install Biovitor filters inside the tank for each inlet, however due to tank size issues, now we would like to install ONLY one filter in the inlet for the rainwater from landscaped areas.
Tank inlet for water collected from roof – NO FILTER
Tank inlet for water collected from landscaped areas – WITH FILTER
Water runoff from roof is approx. 75% of total site runoff. Biovitor filters have more than 90% of TSS removal efficiency.
Since runoff from roof is practically not polluted we would like to focus on eliminating TSS from landscaped areas runoff. We believe that if we are able to demonstrate that
TSS concentration in water tank using filter
Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
186 thumbs up
April 20, 2016 - 8:07 am
The credit calls for you to remove 80% TSS, you need to do the math and prove that you do this. The credit does not dictate how you do this. I would, however, disagree with your assumption that roof runoff is "practically not polluted" and would not recommend that you completely leave the roof area out of the math.
You need to develop a total poundage of TSS for your site, and remove 80% of the poundage.
Typical roof poundage is around 21 EMC mg/l which works out to about 9.6 lbs/ac
I would recommend implementing some form of dead storage in the roof tank, and make the case that the TSS settles out and you have 100% removal efficiency.
Manuel Martin Delgado
Buro Happold Polska Sp. z o.o5 thumbs up
April 26, 2016 - 11:10 am
Thank you Michael for the reply.
We have developed calculations showing 2 cases:
CASE 1: without any TSS removal solution:
TSS in water coming from roof: 455 mg
TSS in water coming from green areas: 2734 mg
TSS in water from hardscaped areas: 12273 mg
total: 15462 TSS mg
CASE 2: with filter installed in inlet for runoff from land/hardscaped areas:
TSS in water coming from roof: 455 mg
TSS TSS in water coming from green areas (filtered): 410 mg
TSS in water from hardscaped areas (filtered): 1841 mg
total: 2706 TSS mg.
if we show this type of calculation, would it be enough for demonstrating compliance?
We have used the following TSS concentration values taken from the NY State Stormwater Management Design Manual annex A:
Commercial roof: 9mg/l
Green area (lawn): 602mg/l
Hardscaped areas: 468 mg/l
Are the values above fine? they are given as general values for those areas.
a concentration of 21mg/l in water from seems to be closer to residential roofs than to commercial roofs.
would it be correct to use 9mg/l for roofs?
thank you
Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
186 thumbs up
April 27, 2016 - 7:49 am
I think you are taking the correct approach with this now. By all means, if 9 mg/l is coming from a BMP Manual that regulates the area your where your project is being constructed, use that.
You just need to be able to defend your calculations, with a straight face.
I think you are well on your way. Good luck!
Manuel Martin Delgado
Buro Happold Polska Sp. z o.o5 thumbs up
May 19, 2016 - 3:30 am
thanks again for your response.
We will try to follow this approach, however my only concern is whether the TSS concentrations given in the manual will be accepted for our project. Our project is located in Europe, however the TSS concentrations I have taken are coming from the NY state manual and I am afraid the reviewer might have comments on this. Any experience on using data from a different location than where the project is? I wonder that if we are not able to find TSS concentration data from local source, we might be risking the credit.
Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
186 thumbs up
May 19, 2016 - 11:19 am
You need to pass the straight face test. I'd compile several sources, and make an educated judgment.