here we are saving a lot of water and making safe compost!
has anyone had any experience with composting toilets...it's kind of a gloified outhouse, i guess, but without the smell and worrying about whats going to bite you!
Rainwater Harvesting for Landscape Irrigation: The Good, the Bad, and the Ugly side of Roof Runoff
by Natasha T. Nicholson, Brett V. Long, Shirley E. Clark, Ph.D., P.E., D. WRE
Penn State Harrisburg, Middletown, PA
One aspect of green engineering and sustainable design is how man interacts with the hydrologic cycle. This includes how stormwater runoff is managed and whether runoff is viewed as a waste product or an opportunity. Rainwater harvesting is a critical component in integrated urban water management. If rainwater harvesting barrels/collection tanks are widely distributed and used in conjunction with other water-sensitive development practices such as low impact development and/or conservation design, a substantial fraction of runoff can be removed from the drainage system. This, in turn, potentially would reduce sewer overflow events and reduce bacterial and other pollutant concentrations in receiving water bodies. In addition, the used of harvested rainwater for outdoor uses such as watering lawns and gardens could reduce domestic potable water consumption by 10% - 30%. The use of roofs (potentially such as those in Figure 1) for rainwater collection is not a new technique, but is becoming more common as people’s awareness of potable water limitations and costs increase. While there are many benefits to using harvested rainwater from roofs, there are also possible negative impacts.
Roofs as a good source for harvested rainwater
Roofs are an ideal location for rainwater harvesting for three main reasons. First, gravity can be used to collect runoff thus eliminating the need for electricity for pumps. Second, when compared to toilet and other household wastewater, water collected from roofs could be relatively clean. Third, a second and separate plumbing system would not be required. Other side benefits of using reclaimed water include cost savings to the consumer via reduction in municipal water consumption and increased efficiency for the drinking water authority in that less water must be treated, especially during hot, dry days when overall water use is likely to be higher.
Potential problems with harvested rainwater from traditional roofing
While roofing seems like an obvious choice for rainwater harvesting, there are some drawbacks in using this resource. Laboratory studies of roofing materials purchased at a local big-box hardware store demonstrated the potential for pollutant leaching into the environment (Clark et al., 2004). A large reservoir of nutrients and metals existed in these materials, and, if the environmental conditions were favorable, some of this reservoir potentially could be released into the runoff. Some common high level contaminants include: pH, nitrate, phosphorus, and heavy metals. Field studies also have confirmed the important role played by roofs, paved surfaces, treated woods, and other construction materials in the pollutant loading of stormwater runoff (Clark et al. 2008a, which contains an extensive reference list and summary table of the literature).
In the past, it has been assumed that, as roofing materials age, their ability to release pollutants decreases to a low-level, steady-state value. However, aging due to, for example, fluctuating temperature and ultra-violet light exposure, and the ongoing interactions between the roof surface and the chemicals in the rainfall can result in newly exposed subsurfaces. These subsurfaces may not have been sealed to prevent degradation, because they were not expected to be exposed to the outdoor environment. Testing at PSH on two old (60+ years) painted, galvanized metal roof panels asphalt shingles (Figure 3), showed that pollutant release could continue for at least 60 years (Clark et al. 2008b).
Although pollutant releases can occur at any point in a roof’s lifespan, generally, it is thought that there are two periods of concern for pollutant release – early and late life. During the early life, excess sealants and potential surface contamination wash off. This release decreases over time with environmental exposure. Because initial pollutant concentrations are likely to be high (exhibiting a first-flush of the lifespan), this time period is of most concern for roof runoff either that enters receiving waters and potentially harms both fauna and
and flora downstream or that is captured for future use. The second time of concern is the end of life where the material degrades so greatly that the subsurface/subbase materials are exposed and pollutants released from these lower layers of material. Several states and other water authorities have published guidance on the appropriate selection of roofing materials for rainwater harvesting for landscape irrigation. This research investigates the runoff quality from these recommended surfaces.
Potential of Extensive Green Roofs for Rainwater Harvesting
Extensive green roofing, where the media depth is shallow and the plants are typically drought-and heat-tolerant alpine species, has been examined as a means of reducing the volume of and improving the quality of stormwater runoff. The research at Penn State Harrisburg by Long et al. (2007, 2008) has confirmed the ability of the green roof, both through potential plant uptake and growth/drainage media filtration of the rainfall, to neutralize acid rain and to remove certain pollutants from the rainfall. Extensive green roofs, for example, in central Pennsylvania, are documented to return approximately one-half of the annual rainfall to the atmosphere through evaporation and plant transpiration. This is a substantial reduction in runoff volume when compared to a traditional roof. However, this still leaves 50% of the rainfall to become runoff. This runoff, if it is of appropriate quality, may be available for capture and reuse with minimal treatment after passage through a growth and drainage media that also filters out pollutants.
For green roofs, the early stage encompasses plant establishment, washout of fine particles from the media, ... (what we are trying to say is that it takes a few storms for the finer grains of media to wash out. It's like planting a container plant - the first few waterings see some of the soil washing out). The late life definition is still being studied/defined, but it may be when either the plants do not have sufficient nutrients left in the media to be healthy or when the removal capacity of the media for rainfall pollutants is exhausted. Penn State Harrisburg has several pilot-scale green roof tests ongoing to evaluate both runoff generation (compared to rainfall quantities) and pollutant removal of green roofs (Figure 5).
Roofing materials that pose the least problems in terms of runoff quality
Sustainability initiatives typically focus on rainwater harvesting for landscape irrigation. New studies conducted at Penn State Harrisburg have concentrated on the weathering of roofing materials and the effects of this degradation on roof runoff water quality. Ongoing research highlights the water quality concerns, and potential need for treatment, in the runoff from several common building materials previously advocated for harvesting. If the runoff pollutant loading is high and if the runoff is not treated, potential pollutant accumulation may occur in soils and/or stream sediments – causing problems for the landscaping plants or the aquatic organisms.
The results show that, during the early life of a roofing system, several of the traditional roofing materials (shingles, cedar, uncoated galvanized aluminum) release pollutants into the rainwater (Figures 6 and 7; the box on these box-and-whisker plots bound the 25th and 75th percentile concentrations, while the whiskers show the 10th and 90th percentile concentrations). These pollutants then may be transported in the storm drain system and, eventually, to receiving waters. If the water is harvested for use, several of these materials release pollutants for at least one year after installation at concentrations high enough to be of concern for plant toxicity. Based on these early-life results, it appears that the green roof may not clean the rainwater, but it also does not add pollutants to the water at levels that may be toxic, unlike the uncoated metal roof and metal-impregnated woods. Other findings indicated exposed treated woods and uncoated galvanized metals appear to be inappropriate because of their high metals’ releases for rainwater harvesting, and possibly for direct receiving water discharge as well for a minimum of one year after installation. The roofing material that has shown the least amount of leaching was the coated metal. This research has been performed in the mid-Atlantic region of the United States, and the timing of this early life washoff may vary by region and may be a function of climatic factors, with accelerated aging and pollutant release in areas with high UV exposure and larger temperature fluctuations. It has also measured only total forms of the pollutants and not the potentially more bioavailable dissolved fractions. Further research will be required to determine whether the pollutants seen in this research are bioavailable either to aquatic life or to landscape plants.
Figure 6. Copper (top) and Zinc (bottom) concentrations for several roofing materials © Shirley E. Clark, 2008.
Figure 7. Nitrate (top) and Total Phosphorus (bottom) concentrations for several roofing materials © Shirley E. Clark, 2008.
Research also is ongoing to relate the degradation and runoff quality to climatic factors such as interevent period, rainfall intensity, UV exposure, and temperature. Developing relationships between climatic factors and runoff quality will be important, especially if, eventually, an effective series of rapid laboratory tests can be used to predict the environmental friendliness of roofing materials for rainwater harvesting.
Additional information and pdf files of presentations related to this subject can be found at www.personal.psu.edu/sec16/.
The authors would like to thank the multitude of people who made this research possible. From Penn State Harrisburg, this includes the funding from the Graduate Research Council and the School of Science, Engineering and Technology, and the work of the following students: Julia Hafera Spicher, Kelly Franklin Steele, Jim Elligson, Brad Mikula and Christina Y.S. Siu. Dr. Robert Berghage of Penn State University’s Department of Horticulture was invaluable in helping set up this project and educate us about green roofs. This research is being performed as part of Mr. Long and Ms. Nicholson’s thesis projects.
The authors also would like to express their appreciation of the assistance of Dr. Robert Pitt, Ms. Elizabeth Graham and Dr. Pitt’s graduate students for their metals digestion and analysis of a portion of the samples. From the University of Alabama at Birmingham, the authors would like to thank Dr. Melinda Lalor for her support during the entire project, including her work with Dr. Clark on the laboratory testing of the materials in 2004. She also provided support for two students from PSH to participate in the NSF REU program in Environmental Health Engineering, when UAB was attempting to establish a similar setup between hurricanes. Finally, the authors would like to acknowledge the support of the Alabama Water Resources Research Institute for the initial laboratory work performed at UAB.
This post was modified from its original form on 13 Jun, 14:34
it is raining very hard here...water pouring into my temporary rainbarrel garbage cans and overflowing...plus pouring over sides of back gutter. need another downspout OR i'm thinking of a rain chain. i could make one, but there are some really beautiful ones made...look behind diane leafe christian in her interview video. need to find some good sized, inexpensive barrels too.
i'd really like to do a whole house grey water system...don't know it it is legel around here.
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Greywater Central, at Oasis Designs. A very comprehensive site.
Introduction to Greywater Management by EcoSanRes.
High-end greywater systems from Clivus Multrum.
California's Graywater Guide Book and code -- mandates very restrictive and expensive systems.
Water CASA- has downloadable publications and explanation of the best state greywater code, Arizona.
The City of Malibu, CA's Graywater Handbook.Recycling Water the Greywater Guerrillas' Way
Greywater is water that flows down sink, shower, and washing machine drains--but not the toilet. Greywater may contain traces of dirt, food, grease, hair, and household cleaning products. While greywater may look “dirty,” it is a safe and even beneficial source of irrigation water. If released into rivers, lakes, or estuaries, the nutrients in greywater become pollutants, but to garden plants, they are valuable fertilizer. Aside from the obvious benefits of saving water (and money on your water bill), reusing your greywater keeps it out of the sewer or septic system, thereby reducing the chance that it will pollute local water bodies Reusing greywater for irrigation reconnects urban residents and our backyard gardens to the natural water cycle.
The easiest way to use greywater is to pipe it directly outside and use it to water ornamental plants or fruit trees. This avoids the potential risk of transmitting disease-causing microorganisms. Greywater can be used directly on vegetables as long as it doesn't touch edible parts of the plants. In any direct greywater system, it is essential to put nothing toxic down the drain--no bleach, no dye, no bath salts, no cleanser, no shampoo with unpronounceable ingredients, and no products containing boron, which is toxic to plants. It is crucial to use all-natural, biodegradable soaps whose ingredients do not harm plants. In an effort to reduce phosphate pollution of lakes and rivers, many counties have banned phosphate-based detergents. Most powdered detergent, and some liquid detergent, is now sodium based, but sodium can keep seeds from sprouting and destroy the structure of clay soils. Chose salt-free liquid soaps. While you're at it, watch out for your own health: "natural" body products often contain substances toxic to humans, including parabens, stearalkonium chloride, phenoxyethanol, polyethelene glycol (PEG), and synthetic fragrances. (to learn more about what’s in your products, go to www.cosmeticdatabase.com and see how they rate for toxicity). Read our recommendations for soaps and products here.
Greywater is more alkaline than rainwater. Plants that normally grow in acidic soils—for example forest and bog plants—do not tolerate greywater well. Non-phosphate detergents raise the salt content of greywater. In areas with regular rainfall, rainwater leaches salts below the root zone of plants, avoiding these problems. In drylands, salts can be diluted by irrigating alternately with greywater and stored rainwater.
Does your greywater need treatment? The easiest way to use greywater is to pipe directly to the garden and use it to water ornamental plants or fruit trees. Applying greywater directly to the soil surface or just below it minimizes the risk of transmittin
any disease-causing microorganisms greywater might contain. The simplest way to infiltrate greywater is by sending it into a mulch basin or a bucket infiltrator in biologically-active topsoil. Plants consume nutrients and soil organisms break down grease and particles. The most difficult and most problematic use of greywater is for watering lawns. To minimize the possibility of human contact with greywater, expensive underground infiltration lines must be installed. We recommend tearing out your lawn and replacing it with a garden!
In most cases, greywater needs no treatment. Prefabricated greywater systems (i.e. those made by BRAC) use filters and chlorine disinfection to “treat” greywater. Although greywater can contain some fecal indicator bacteria, there has never been a documented case of greywater-linked illness. Like other long-time greywater users, we have found that crop irrigation poses no significant health threat as long as greywater does not contact edible portions of the plants. Chlorinated greywater will kill beneficial soil organisms and poison your plants.
Greywater will clog up your drip lines and MUST be filtered. Manufactured systems (i.e. ReWater) use sand filters that must be back flushed to remove the particles they trap. Since graywater is high in suspended solids, these systems require a lot of maintenance. In situations that require drip systems, we recommend first treating water in a wetland, then using a sand filter if more treatment is needed. However, wetland treatment will use up a lot of the potential irrigation water, so these complicated and costly systems makes sense only in apartment buildings where large commercial buildings create large graywater flows. For single-family homes, we recommend the low-tech strategies discussed above.
In addition to being beautiful water gardens in and of themselves, constructed wetlands have another important application. At a small urban site with little or no need for irrigation water, a wetland can keep greywater out of the evil sewer by disposing of it via evapotranspiration by wetland plants. The larger the wetland, the less greywater you’ll get out at the end, especially during hot weather. Alternatively, send greywater directly to the garden during the growing season, and use a wetland to “dispose” of the greywater when irrigation water is not needed. In cold climates, where the soil freezes during the winter, constructed wetlands can treat greywater year round. Treated greywater can be released into a sump below the frost line during the winter. For more information on wetlands click here.
Each greywater system will be slightly different, depending on your house and site. These are examples of some of the most common systems.
- "Drumless Laundry" (Our new favorite for washing machines)
- Branched drain (For showers and sinks that can use gravity) Explanation from Oasis Design
- Constructed Wetland
- Don’t store greywater (more than 24 hours)
- Minimize contact with greywater
- Infiltrate greywater into the ground, don’t allow it to pool up or run off (knowing the soil percolation rate of your soil and designing mulch basins will help with this)
- Keep your system as simple as possible, avoid pumps, avoid filters that need upkeep.
- Match your plants irrigation needs with the amount of greywater they’ll receive.
Greywater policies differ state to state. The best policy if for the state of Arizona. They have greywater guidelines to educate residents on how to build simple, safe, efficient, greywater irrigation systems. If people follow the guidelines their systems falls under a general permit and is automatically “legal”, that is, the residents don’t have to apply or pay for any permits or inspections.
California also has a greywater policy but it is very restrictive and usually makes it unfeasible for people to afford installing a permitted system. Because of this the vast majority of systems in California are unpermitted.
Some states have no greywater policy and don’t give permits at all, while other states give experimental permits for systems on a case-by-case basis.
To read about greywater policy visit Art Ludwig’s policy page, or read our summary of greywater recommendations.
the above is an interesting site...click on to composting toilets to read about the pee and poop revolution. much more and lots of links listed there
see video in gardening...because it's compost!
Introducing the Thunderbox mobile compost toilet - the first of it’s kind! The Thunderbox Collective are now making Thunderboxes to order, or you can hire them. Thunderboxes are ideal for a wide variety of situations as they are easy to assemble and take down.
Thunderboxes give total flexibility whilst maintaining sanitation standards and user comfort, and are the environmental alternative to the standard chemical loo, which have high-embedded costs, minimal capacity, strong chemical usage and highly consumptive water requirements.
Existing port-a-loo provision represents a very unsustainable and often unpleasant experience, and requires specialist smelly disposal, employing large vehicles generating high “Poo-miles.”
There are clear social, environmental and cultural benefits for using a viable alternative. We, the Thunderbox Collective are on that mission!
Thunderboxes are made using sustainable timber provided by ‘wood4trees’, sourced from Devon woodlands classified as PAWS (Plantation on Ancient Woodland Site). These are managed using continuous cover techniques, and the timber extracted is assisting the conversion of the plantations back to native broadleaved woodland.
A number of other components used in the construction of the Thunderboxes (including the bulk containers) are of recycled origin.
By definition, a compost toilet produces compost, not waste. Thunderboxes have demonstrated easy production of friable compost.
How does it work?
To create safe and useful compost,the material needs to either spend considerable time composting away from human contact, thereby breaking the pathogens cycle, or by rapid “Hot composting.” Oxygen loving bacteria are present almost anywhere there is both organic matter to break down and oxygen supply - they just turn up!
They do have specific requirements though. Just like a fire they need oxygen and fuel in the right condition. The “fuel” in this case is our “deposits” plus “soak”, usually sawdust or straw. This produces a mix of carbon to nitrogen around 30:1. The oxygen loving or Aerobic bacteria will attack this with fervour given good oxygen supply.
The unique bulk turn-ability of the Thunderbox containers enables tumbling of the compost at our convenience, with the more turns the greater the speed of composting.
A cubic metre of fresh compost will reduce by one third in a month and reduce to one third its original bulk in three months with turning once a week. With careful monitoring it can get to 55-60 degrees Centigrade!
This will kill all known pathogens to humans in hours!
However, has every molecule reached this temperature? We like this sort of heat level, but also compost for months and generally don’t use our compost inside two years. By then it is virtually soil and full of nutrients and high humic content.
Purchase your Thunderbox either as a DIY kit or we'll come and build one for your annual event, allotment, campsite, low impact dwelling, small-holding, stable yard etc.
We have a number of units available for event Hire. We generally only operate in South-West England due to the generation of ‘poo-miles!’
Run your own
FROM A CO-FOUNDER OF THE ORIGINAL
COMPOSTING TOILET, CLIVUS MULTRUM
comes a new generation of long term composting toilets with a radical new performance standard that can replace all other toilets in permanent dwellings, vacation cottages and public toilet facilities ... on rocky archipelago islands, on beaches, golf courses, camping grounds or just about anywhere.
It is hygienic, odor-free, environmentally the best, simple to install, handsome and inexpensive. It does not use or pollute water, requires minimum maintenance and solids only have to be removed 3-5 times per 100 years when properly sized.
You can install it inside or outside.
What people appreciate most is that the bathroom is always completely odor-free: when you come to the toilet, when you use it and when you leave it -- all odors are ventilated down into the toilet itself.
What distinguishes CompostEra from other toilets is a simple and basic idea: all that you see and use in the bathroom shall be as attractive, hygienic and comfortable as can be. All that you cannot see shall be as practical and well functioning as possible. The bathroom units are specially designed for the purpose, and the composters themselves are robust, tried and tested, standard manufactured products, that we rebuild. This is why we are half to one third the price of comparable equipment solutions on the European market.
You can also order our products directly on-line
lots of comments and links that are helpful. one person questioned what happens to medications that are in ones system. good question. i wonder what the answer would be.
good information on compost toilet, grey water.
anybody using grey water? it seems like such a good idea and yet it isn't even legal in a lot of places.
how do you find out about what is legal in the area? if i could reuse laundry, bath water, and cleaning water to water my poor thirsty plants, it would be wonderful!
i'm not sure i can deal with compost toilets yet!
clean water is becoming more precious. we are being so wasteful and taking it for granted that it will always be here...but it won't!