RAINWATER HARVESTING RETURN ON INVESTMENT BENJAMIN SOJKA RAINWATER MANAGEMENT SOLUTIONS

Transcription

1 RAINWATER HARVESTING RETURN ON INVESTMENT BENJAMIN SOJKA RAINWATER MANAGEMENT SOLUTIONS

2 Benefits of rainwater harvesting 1 inch of rain on a 1,000 ft 2 roof yields 620 gallons of collected rainwater Decreases use of municipal water --- worldwide consumption is growing at double the population growth rate Reduces reliance on energy-intensive, aging water infrastructure Decreases stormwater runoff, which is a major source of pollution

3 Why Reduce Stormwater Runoff Urban infrastructure increases the imperviousness of the environment and pollutes and concentrates stormwater. DC is 43% impervious. In cities, like Washington, DC, with combined sewers the stormwater can overburden the combined sewers and sewage treatment capacity. About two billion gallons per year overflows to the Anacostia and Potomac rivers. Combined sewer overflow events result in cities being sued by the EPA for violations of the clean water act.

4 What DC is Doing to Avoid Violating the Clean Water Act DC Clean Rivers Project is in the process of digging large tunnels to be used to divert the CSOs from the receiving waterways and retain that water to be treated by Blue Plains WWTP. Cost of DC tunnels - $2.6 Billion Cleveland - $3 Billion Kansas City - $2.48 Billion New stormwater regulations aimed at making DC spongier to reduce the amount of stormwater entering the combined sewers.

5 Changes to DC Stormwater Regulations New construction over 5000 sq. ft. must retain first 1.2 of rainfall (90% of storm events). Major renovations must retain first.8 (80% of events) Retained water must be disposed of on site. Infiltrate, fixture flushing, cooling tower, evaporate, etc At least 50% of required detention must be done on site. Remainder can be purchased as credits. Credits can be purchased from DDOE for $3.50 per gallon per year or in the private marketplace.

6 Percent of demand met by rainwater Rainwater harvesting for Stormwater Management Sizing guidelines and regulations per DDOE Stormwater can be detained and reused on site New emphasis is on runoff 40 reduction Works best as part of a 10 treatment chain Tank size ( thousands of gallons)

7 Where to Capture Rainwater Best Practice Rooftops The best and cleanest water comes off the roof. Handle with Care Green Roofs and Planted Areas Water from green roofs is often high in dissolved solids from the growing media. Not good for toilet flushing May work for irrigation or cooling tower makeup Parking Lots Often contains oils and dissolved salt. Salt is difficult to remove and detrimental to plants

8 Possible Uses of Rainwater HVAC cooling systems Commercial laundries Water closets and urinals Irrigation Pool and pond Filling Other non-potable uses (fire suppression; floor and vehicle washing)

9 Rainwater Harvesting and LEED 11 Possible Points Reduce or eliminate pollution from stormwater runoff Limit disruption and pollution of natural water flows by managing stormwater runoff Limit or eliminate the use of potable water for landscape irrigation Use only captured rain or recycled site water for site irrigation Reduce potable water use for building sewage conveyance by 50% Reduce water use for building by 20% Maximize water efficiency within building to reduce the burden on municipal water supply & wastewater systems

10 No matter how big the job is, the concepts are the same You just have to choose the right tools

11 Size Matters! Larger Tanks Usually below grade Tend to utilize the captured rainwater more efficiently Rainwater Harvesting Want the tank full Stormwater Management Want the tank empty Control systems can help manage tank capacity Smaller Tanks Architectural Feature Tend to be much cheaper Can reduce the cost of the rainwater system Some clients want them above grade to show off system

12 4 Steps for Rainwater Harvesting Self-cleaning filters Smoothing inlet Floating filter intake Multifunction overflow

13 1 Putting it all together Grade Storage tank

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15 Two Ways to Build a Rainwater System A La Carte A group of parts and pieces are sourced and assembled on site usually following a project specific scenario. Skid System The system is predesigned and prepackaged with minimal on-site construction.

16 Some Considerations for A La Carte Systems Increased possibility that the installing contractor might not assemble the components in the order that the designer intended. Liability concerning installation must be clearly defined and understood between all parties. Some of the equipment may be delicate and, if poorly understood, may be damaged and or broken during installation. This will fall on the contractor.

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18 Skid System On-Site Hook Up Inlet from Cistern To End Use Filter blowdown Domestic Water supply line

19 SYSTEM CONTROLLER

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26 Urban farm

27 Charlottesville Public Works

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30 Charlottesville Area Transit

31 Jefferson Houston Elementary School Skid System

32 Jefferson Houston Elementary School Skid System

33 Home Depot

34 Boeing Crystal City, VA

35 Boeing Crystal City

36 Boeing Crystal City No Pre-Filter

37 Kellum High School, Virginia Beach

38 701 2 nd Street, Washington, DC 450 Unit Apartment

39 ICC Bethesda High Security Office Building

40 Oscar Smith Middle School

41 A two-tiered approach Two clean tanks are used for indoor use toilets and urinals The other two tanks are used for irrigation

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43 Manassas Park Elementary

44 Manassass Park Elementary School 61,500 sf of additional roof area (12,000 pre-k; 49,500 upper elementary) Estimated project budget $33 million

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49 Effect of system Eighty-two percent of the precipitation that falls on the roof is used in the building or for irrigation (1.1 million gallons). Any additional runoff is routed to the constructed wetland for infiltration or evaporation or in extreme events, detention and release. The initial estimates used in sizing the system were based on monthly rainfall data. This difference in time interval is why the signs and other early estimates predict an annual water savings of 1.3 million gallons. The school uses about 356,000 gallons of water per year; the neighboring school (Cougar Elementary) uses 2.2 million gallons of water per year. LEED Gold certified Numerous awards including K-12 Project of the Year, Mid-Atlantic Construction magazine Platinum Design Award and People's Choice Award, 2009 Virginia School Board Association Exhibition of School Architecture; 1st place in the 2007 Go Green Competition, USGBC James River Chapter AIA/COTE Top Ten Green Projects

50 Manassas Park Elementary School- Education component

51 Western Virginia Regional Jail Regional partnership between the counties of Franklin, Montgomery, Roanoke and the city of Salem 264,000 sq. ft. with a rated capacity for 605 inmates Seeking LEED certification Includes a siphonic roof drainage system

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54 Payback analysis Total system cost = $258, million gallons of water saved Current water rate $3 per 1,000 gallons Annual savings from water = $11,675 Total payback time = 22 years But does that really include everything?

55 Payback analysis Offsetting capital costs the rainwater harvesting system has the same water quality benefits for storm water as a bioretention area that would cost about $240,000 plus take up space on the site Increasing water rates if water rates increase 4% per year, in twenty years, the water savings will have more than doubled ($24,599 per year)

56 System return on investment ($) 1,200,000 1,000, , ,000 Payback with offsetting costs and increase in water rates 400, , , Payback with no offsetting costs and no increase in water rates -400,000 Years

57 Benjamin Sojka Rainwater Management Solutions direct

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59 The Joyce Agency 3933 Avion Park Court, Suite B102B Chantilly, VA

60 Experience Matters! All Souls Church Washington, DC Car Barn Training Facility Washington, DC Wounded Warriors Dorm Facility Bethesda Naval Hospital, MD PH2SO Apartments Washington, DC Patterson House Apartments Washington, DC 800 New Jersey Avenue Washington, DC 880 New Jersey Avenue Washington, DC Park Chelsea Apartments Washington, DC 2001 Clarendon Apartments Arlington, VA 9 th Street Office Building Richmond, VA Fairfax Public Safety Building Farifax, VA

61 Experience Matters! I.C.C. Government Security Complex Bethesda, MD St. Elizabeth s Rehab and Renovations (2) Washington, DC H.D. Woodson High School Washington, DC Brookland Middle School Washington, DC University of the District of Columbia Greenhouse Washington, DC Anacostia High School Washington, DC Arlington Mills Community Center Arlington, VA Kempsville High School Virginia Beach, VA Gunston 9 Secure Facility Lorton, VA

62 Experience Matters! Mathias Research Center (Smithsonian) St. Mary s County, MD Monument View Center (Boeing) Crystal City, VA 82 Eye Street Washington, DC Caffie Building Arlington, VA Manassas Elementary School Manassas, VA University of Maryland Knight Hall College Park, MD Hillen Street Fire Station Baltimore, MD National Business Park Baltimore, MD

63 Experience Matters! Rainwater Management Solutions Over Ten years of rainwater harvesting experience each Have made many of the mistakes and have learned from them Have the financial backing and resources to stand behind their systems