Net Zero Water Project

Net Zero Water Project

Water is an invaluable resource and is oftentimes taken for granted. The Net Zero Water standard is an idea that aims to relieve households from dependence on city water, which will decrease strain on water treatment facilities. By capturing precipitation and treating wastewater produced on site, occupants of a household will close the loop of their water system, thus leading to water independence. This site sets out to document my process and research as I look further into this exciting topic.

August 31, 2009

Discussion at local Green Developer

by Wes

See how Postgreen Homes may be interested in the Net Zero Water Project and read some dicussion on the topic here

As always, feel free to leave suggestions in the comments anywhere on this site, as every bit of information is helpful.

August 26, 2009

Informative Documentary

by Wes

FLOW (For the Love Of Water) is a documentary made in 2008 concerning the global problems associated with fresh drinking water.  I highly recommend this film:

The Living Building Challenge

by Wes

The LBC challenge exceeds LEED platinum and begins to re-imagine how our built world can better coexist with the natural world.  If everyone stepped up to the Living Building Challenge, we could make a significant impact on our society, economy, and culture.  Perhaps the biggest deterrent in chasing after this goal is how meticulously detailed the prerequisites are to achieve the standard.

Responsible site selection is listed as the first prerequisite.  Of course it’s important to respect our environment, and it is also important not to interfere with any naturally-occurring systems such as wetlands or prairies.

Energy is obviously an important one here, as well.  All energy must come from the sun, and the building is required to be net zero energy, which means that it produces more energy than it consumes.

Material selection is also a major factor in LBC projects.  There is a “red list” of materials that is supplied with the challenge, and none of the listed materials may be used in any way during the construction.  These materials include CFCs, cadmium, Neoprene, HCFCs, formaldehyde, PVC, lead, mercury, pthalates, petrochemicals, and more.

Location and distance traveled of services and goods to the project must be kept to a minimum.  There is a radius around the site that builders/developers are allowed to draw their resources from.

All on-site construction waste must be managed and recycled.  There can be no waste produced from building a LBC certified building.

Of course, net zero water is a factor, and probably the one that most people tend to shy away from.

There are more aspects to a Living Building, but this post just serves as a general overview.  If you’d like to get a more comprehensive look at the LBC challenge, you can view a pdf of the LBC in its entirety here

August 21, 2009

About Rainwater

by Wes

Precipitation that falls onto a site and hits impervious surfaces, such as a roof, and then runs off is considered rainwater.  Rainwater has been collected for as long as humans have been around, and there are several innovative and intelligent systems that use rainwater collection as a source for freshwater.  Rainwater is naturally produced and is the cleanest of the three types present in a net-zero water system.  Because of this, it requires light filtration followed by UV sterilization to be used for potable purposes.

The amount of rainwater available to a property varies heavily on the climate of where the property is and the time of the year.  In our region of Philadelphia, rainwater falls at a pretty even rate, but still fluctuates depending on the month.  Here’s a list of average rainfall for the Philadelphia region:

Treated rainwater will be primarily used for potable purposes, mainly the kitchen sink and dishwasher, as well as showers and bathroom sinks throughout a household.  If there is an overabundance of rainfall during a certain period of time, or a lack of greywater being produced and treated, “raw,” or lightly treated rainwater can be used for purposes such as irrigation, toilet flushes, and washing machines.

About Greywater

by Wes

Greywater is not potable, but with proper treatment and UV sterilization, it can be.  The primary contributors of greywater to the system are showers, bathroom sinks, and washing machines.  Although rainwater is the freshest without treatment of the three types of water (black, grey, rain), greywater is a close second.  If there is not enough rainwater falling or stored to be used for all the potable water needs of a house, greywater can be treated and used to supplement the rainwater.  It requires more energy to treat, but overall would be less expensive than purchasing more water from the city.

Living machines, which mimic natural wetlands, are used to naturally treat greywater.  This is accomplished through a series of stages involving plant and animal life.  The effluent of a living machine is clean enough to be used for a variety of things, but with some sterilization it can be used to drink.  After treating greywater through a living machine (which requires little energy due to gravity-fed compartments and natural systems of filtration), the water can be returned to the system for toilet flushes, fire suppression storage, washing machines, and irrigation purposes.  As I mentioned, it can also be further sterilized and used for kitchen sinks, showers, dishwashers, and other potable water users.

Here’s a conceptual model of how a living machine works, from a past project of mine:

About Blackwater

by Wes

The most difficult aspect of achieving a net-zero water standard is treating and returning your blackwater back into the system.  Blackwater treatment in itself is difficult, and requires an expensive membrane bioreactor (MBR).  The organic matter must be separated out from the liquid and treated differently.  The biosolids produced can be used as fertilizer for non-edible crops and the liquid can be treated and returned to the system.

Source: Achieving Water Independence In Buildings via International Living Building Institute

The key players in the system that produce blackwater are toilets, kitchen sinks/ garbage disposals, and dishwashers.  Anything that contains organic matter contaminates the wastewater produced with bacteria, viruses, and pathogens.  Good practices in the kitchen can limit the amount of blackwater to be treated by the system, but there will always be people eating and producing waste in the system, and these things require the presence of an MBR.

At this stage the water is not potable, but it is clean enough to be used for a variety of other things.  Once treated, the water output from an MBR can be used to refill toilets for flushing, irrigation needs, washing machine water, and to supply fire hydrants with water.

Some Facts About Philadelphia’s Water

by Wes

Philadelphia is situated in the southeastern portion of the Delaware Basin, and the city is supplied water from two rivers – the Delaware River and the Schuylkill River.  The surrounding suburbs have a big impact on the quality of water that comes into our treatment facilities, and these suburbs are quickly-expanding.  While the population of Philadelphia county has recently dropped about 22%, the subsequent populations of Montgomery and Bucks counties grew by 20% and 44% respectively.  Both of these suburban counties are largely part of both the Delaware and Schuylkill watersheds.

The Delaware watershed is 330 miles long and runs from New York through Pennsylvania and New Jersey, all the way down into Delaware.  It also provides water to a whopping 10% of all Americans.  As with most watersheds across America, threats to the Delaware include waste dumping, bad agricultural practices, erosion/runoff problems, industrialization, transportation, and coal mining.  Another common problem with pollution in the water supply that affects the Delaware is overflowing sewer systems from prolonged periods of rainfall.  This problem has occured in many parts of the United States, and a good solution is to collect and store rainwater on a residential level, thus keeping a lot of runoff from flooding the overburdened sewer systems.

The Schuylkill watershed is 130 miles long and runs across 11 counties until it eventually merges with the Delaware in South Philadelphia.  A lot of repeat problems plague this watershed, such as overflowing sewers, stormwater runoff, agricultural runoff, and abandoned mine drainage (Schuylkill county).

The Philadelphia Water Department (PWD) operates three plants in the area and does a good job of treating our water supply.  Chlorine-resistant microorganisms, such as Cryptosporidium and Giardia, were detected in untreated water flowing into the facilities.  After treatment, PWD tested the water quality for these microorganisms, and they managed to rid the water of all detectable amounts of both disease-causing organisms.  Turbidity of water was significantly lower than required by state and federal law (80%).

August 20, 2009

An Audacious Goal

by Wes

Water independence is oftentimes considered one of the most stringent goals of the Living Building Challenge.  Achieving Net Zero Water in a residential building may be considered extremely difficult, or somewhat impossible, especially with conflicting laws and regulations in different states.  I know that this is quite a challenge, especially for a student-level project.  In an attempt to thoroughly cover all aspects of this challenge, I hope to lay out a plan to accomplish this project.

In Portland, OR, a group of professionals have banded together to work on a Net Zero Water project, the Pearl Family Development.  Although still conceptual, this project is well on its way to realization.  A non-profit organization called Central City Concern (CCC) provides affordable housing to low-class families in Oregon.  The CCC noticed rising costs of energy and water utility bills, and they set out to reduce such expenses.  They joined forces with SERA Architects, Interface Engineering, and Gerding Edlen Development to achieve net-zero water in the upcoming Pearl Family Development project.

This team of organizations is trying to achieve this goal for their project, of course, but they are also selflessly transparent with the information they garner about making changes and getting this system in place.  A lot of the research I’ve collected so far was informed from this team of people, as they are far ahead in achieving Net Zero Water.  Since this group’s coming together, enough research was gathered to make proposals to Oregon’s governmental bodies to get regulations and laws changed, paving the way for water independence.  Oregon residential and commercial buildings are now allowed to use rainwater for irrigation, toilet flushing, and clothing washing, and treated greywater is allowed to be used for flushing of toilets and urinals.

Portland is a great start, but what about the rest of the United States?  What about the rest of the world?  I live in Philadelphia, and I’d love to see Net Zero Water in Pennsylvania.  What will it take to get PA laws changed?  The Central City Concern, SERA Architects, Interface Engineering, and Gerding Edlen Development have drafted and released a “water roadmap” that explicitly lays out where each regulation or mandate comes into contact with a Net Zero Water system.  This is a huge help, and they are providing a great service to other people who want to do projects similar to theirs in different states.

Source: Achieving Water Independence In Buildings via International Living Building Institute

August 18, 2009

What is Net Zero Water?

by Wes

What is Net Zero Water?

Similar to Net Zero Energy, which produces energy on-site and doesn’t ever consume more than it produces, Net Zero Water is a standard that sets out to close the loop of a household’s water consumption.  In order to achieve this goal, rainwater that falls on-site is collected and stored, and all wastewater produced by the building or its occupants is treated and re-used.  Rainwater is the primary source of freshwater in many regions of the world and is the easiest to treat.  Filtration followed by ultra violet sterilization can make rainwater potable.  Greywater is wastewater produced by the bathtub/shower, washing machine, and bathroom sink.  It is not potable, but it also doesn’t have all the pathogens and bacteria blackwater has.  Blackwater is the murkiest of wastewater produced in homes.  It comes from toilet flushes, the kitchen sink, and the garbage disposal.  Blackwater is difficult to treat because it contains organic matter which must first be separated out from the wastewater.

Rainwater, greywater, and blackwater are treated differently to achieve different outcomes.  For example, in order to supply potable [drinking] water to the house, rainwater or greywater must be treated thoroughly, and without the use of chemicals.  In this case, rainwater is cleaner than greywater and therefore takes less energy to purify, but a household’s specific demands will determine how much water is necessary.

Why does this concept interest me?

Water is a precious resource and is absolutely vital to life.  We’re not using water efficiently right now, and I don’t think it has to be that way.  80% of the wastewater we produce in our homes is greywater, while only 20% is blackwater.  Instead of treating each separately, since greywater requires much less energy to treat than blackwater, we are mixing them together, which contaminates the greywater with pathogens, and we are then forced to treat everything as if it were blackwater.  This inefficiency doesn’t cut it in today’s innovative and intelligent age.

Right now, potable water is used for pretty much all household demands – whether it be toilet flushes, drinking, irrigation, washing laundry, etc.  This means that we’re spending a lot of extra energy treating water to a higher standard than is necessary.  In places where there is no human contact, such as toilet flushes and sub-soil irrigation of non-edible crops, we do not need fresh, potable water.  We can lightly treat greywater produced on site and return them back into the system for these types of uses.

What am I planning to accomplish by researching this topic?

It’d be great to see net zero water in action in Philadelphia, but I’m just curious at this point.  I want to research what others are doing (such as Phipps & CCC) and get a true understanding of sustainable water use systems.

Water independence in homes would be a huge step forward in relieving the city’s treatment plants of a huge burden.  Also, I think it’s important that people know where their water comes from, how it is treated, and how it can be used.  That’s one thing a lot of us have lost sight of.