Dual flush handles or toilets allow the user to select either a half (0.8 gallon) flush for liquid waste or a conventional full flush (1.6 gallons) for solid waste. These systems are prevalent in Europe and other countries outside of the United States, and have recently been implemented in several buildings at Harvard.

The EPA High Efficiency Toilets site provides specifications for tank type High Efficiency Toilets (HETs). The EPA sponsors a WaterSense certification program in which manufacturers may apply to have their products WaterSense certified. The spec includes water efficiency and performance criteria for:

• Single flush, tank-type gravity toilets
• Dual flush, tank-type gravity toilets
• Dual flush, tank-type flushometer tank (pressure-assist) toilets
• Tank-type, flushometer tank (pressure-assist) toilets
• Tank-type electrohydraulic toilets
• Any other technologies that meet these performance specifications.

A standard toilet can be retrofitted with a dual flush handle for approximately $40.  Considering that the City of Cambridge charges about $10 per 750 gallons (100 cubic feet) of water, that cost is paid back with 12 people using two flushes per day for 260 days, saving 3000 gallons of water. The savings increase as the toilet continues to be used. Using dual-flush toilets in conjunction with other water efficient products has allowed several renovations projects to achieve water savings of over 20%, and up to 42% at Blackstone. To analyze these savings, the Mather Dunster team calculated an economic analysis of dual-flush systems. See the Massachusetts Water Resources Authority fact sheet on Ultra Low Flow Toilets for more information.

The EcoCloset by Ecotech Water, LLC is a 0.8 gallon per flush pressure assist system, with an option to install a sensor for automatic flushing. Ecotech offers a ten-year warranty on this system.

Waterless urinals use no water, saving one gallon of water for each use. At Blackstone it is estimated that waterless urinals will save approximately 40,000 gallons of water per year. The cartridges in these urinals funnel the liquid, trap odor with a sealant, filter waste by trapping sediment, and then release the remaining waste down the drain. The cartridge is replaced after a few thousand uses.

Blackstone recently switched out their Sloan oil-based cartridges for Ecotech Water LLC cartridges, a patented system that uses an elastomeric check valve to release liquid into the drains by opening when it is being used, and closing when not in use. Unlike other waterless urinals, there is no oil or sealant. Water can be poured down the cartridge once per month to rinse any crystallization that may occur. Ecotech offers a lifetime warranty on the cartridge. It fits existing Sloan and Falcon systems.

As of December 2005, there are 12 waterless urinals installed in the men's rooms at Kresge Hall of the Harvard School of Public Health. Manager of Operations, Energy & Utilities at HSPH, Daniel Beaudoin, writes “my experience thus far has been nothing short of positive!” 

Experience at the HSPH demonstrates the crucial role of the custodian. Lessons from their experience:

• Given that most urine smells in men's rooms is from "over-spray" caused by bad aim, HSPH updated the cleaning program to include cleaning the privacy partitions, tile wall, floors around the urinals to address the over-spray issue.
• Secondly, the housekeepers were trained on how to properly clean the waterless urinals and to identify when the traps require replacement (the blue vegetable-based oil rises up into the bowl).
• Third, HSPH Operations taught housekeeping staff how to replace the traps. At Kresge, they have found that changing them every three months is working well.

With sound custodial knowledge and willingness to change the cartridges as necessary, waterless urinals can work fine in high traffic areas. However, occasionally, someone will dump soda or coffee in the urinal, which can damage the trap. We recommend polite signage, or avoiding installing waterless urinals at a super-high traffic area, e.g, next to a bus stop.

 The waterless urinals at Kresge are all in high-traffic areas and get a lot of use:

• Three Sloan waterless urinals in the mens’ room by the cafeteria on the first floor have been in use for one year. 
• On the ground floor, by the main lecture halls, there are six in the men's room and one in a handicap unisex bathroom; all have been in use for three months. On the second floor, by the classrooms, there are two waterless urinals that have been in use for six months.
• Sloan aligns with retrofits.

Low-flow faucets and sensors reduce water consumption. There are several 0.5 gallons per minute (gpm) low-flow lavatories around campus. 1.8 gpm options are also available. A conventional sink uses 2.5 gpm.

The EPA has issued a Draft High Efficiency Bathroom Sink specification and certification process.

Ecotech Water, LLC has developed 0.33 gpm and 0.5 gpm low flow sink aerators, using air induction technology, which pulls air into the aerator to increase water pressure. Weld Hill is using a 0.5 gpm sink that uses a solar cell for power.

Conventional showerheads flow at 2.5 gpm, which is the maximum allowed by Massachusetts code. Significant water savings can be achieved with low-flow showerheads, which are available in models as low as 1.0 gpm.

Alsons Fluidics line includes two low-flow showerheads approved by MA code: the 655 series (1.6 gpm) and the 656 series (1.85 gpm).

For Hamilton Hall, project team members brought home showerheads for a one-week trial, and preferred the 1.5 gpm Oxygenics 630 or 640. At this time it is not yet approved by MA code.

Ecotech Water, LLC has patented a 1.0 gpm showerhead, using air induction technology to greatly increase the water pressure. Bricor low-flow showerheads include several options, such as a 0.995 gpm model and several under 1.25 gpm. These are not currently approved by MA code.

Composting toilets use aerobic decomposition to break down waste, which greatly reduces dependency on potable water for sewage conveyance. Composting toilets have become a viable alternative to conventional water closets. The composting toilet testing standard is called NSF/ANSI (National Sanitation Foundation) Standard 41. This link also contains a database of products that meet this standard. See Composting Toilet World for further information on composting toilets.

When integrated as a design goal early in the project, re-using water from lavatories, sinks, and showers can significantly reduce potable water consumption. This requires additional plumbing to separate and transfer this water for use in toilets or for irrigation. For toilet systems, short-term storage or a surge tank system may be required. Greywater can only be stored for short periods of time, so a system for overflow into the blackwater system should be provided. The feasibility of this process should be weighed by considering how much potable water would be saved, the energy used in the system, and maintenance costs.

According to Rainwater Recovery, Inc., up to 55,000 gallons of precipitation falls annually on an average 2,000 square foot New England roof. Harvesting systems range in complexity from simple tanks to large, vaults with automated delivery for irrigation or non-potable indoor plumbing uses. Rainwater Recovery installed an underground rainwater recovery vault-type system for washing Harvard's transportation fleet at 155 North Harvard Street. See Technologies & Products: Site & Landscape for more information. In addition to conserving potable water, the systems also recharge local groundwater supply and reduce polluted stormwater runoff into local bodies of water. In New England, these rainwater recovery systems can be used for irrigation, sanitation, and HVAC make-up water. At Harvard, rainwater harvesting has not yet been used for indoor plumbing purposes. Rainwater Recovery can work with the civil engineer, landscape architect, and contractor, starting early in the design process. To size a system for your project, see Rainwater Recovery Tools and their Sample Project Questionnaire. Contact Philip Reidy, P.E., Principal at 781-647-9500 for an estimate.

Flowering hibiscus plants, orchids, and lily pads are not what generally come to mind when thinking of sewage treatment.  In the fall of 2005, Green Campus staff toured the Solar Aquatic Treatment Center at Paws, Inc. in Muncie, Indiana and found it to be much like a traditional greenhouse, and a very pleasant place.

A solar aquatic treatment facility has been built for the New England Biolabs in Ipswich, MA, along the Ipswich River, one of the most endangered rivers in the country.  Designed for 25,000 gallons per day, its capital costs are outlined in this case study. Two products from solar aquatic treatment facilities can be harnessed; the nutrients and the heat.  The nutrients produced can become food for plants (potentially to be grown into plants for biodiesel fuel) and the excess heat from the greenhouse, which could be used with a heat recovery system to pre-heat air for a nearby building. Contact: David del Porto, the engineer for the project: can be reached at 978-369-9440 or Ecological Engineering Group, Inc.

• John Todd's Eco Machine turns "sludge to water." 

• Hallowell, Christopher.  "Living Machines that make Water out of Sewage".  Time.  29 March 1999.