Image from Solviva.
Each of us produces greywater and black water at home. But what happens to that water once it leaves our houses? If you use products on your body and home that have dyes, chemicals or fragrances, you can be 100-percent sure those ingredients are being absorbed into the soil somewhere nearby.
Conventional Waste Water Control Methods
The problem with waste water is that conventional “approved” methods don’t work at all for nutrient reduction.
There are two goals of a waste water system: first, to treat the waste in a sanitary fashion so pathogens don’t get out into the environment; and two, to reduce or eliminate nutrients we add to the environment through wastewater we dispose of.
Conventional systems handle the first goal very well but fail miserably on the second goal. In places like Redwood, NY, the problem is even worse because of shallow rocks and poor soils. For all intents and purposes, a pipe leading from a cottage directly to the lake has about the same benefit for nutrient reduction as a septic system. This is not to say that our septics are the only nutrient source problem; but they are a major component and something we could actually do something about.
Septic tanks cause horrible pollution. They leach nitrogen and viruses, antibiotics, toxins, hormones (the "VATHs") into our groundwater (our drinking water!), which then flows into our coastal waterways. After heavy rains, even the bacteria leach through, polluting our beaches and ponds, causing painful diseases. Boards of health post "No Swimming: Polluted Water". As news spreads nationwide, mega dollars are lost as reservations for cottages, hotels, cars, bikes, boats, planes and restaurants are canceled. It is truly hard to believe that the state DEP still requires septic systems for managing our wastewater, especially since these facts have now been known and proven for years.
Blackwater and Greywater
Septic waste can be further broken down into “blackwater” (human waste) and “greywater” (used shower or bath water). Both hold lots of nutrients. Blackwater is primarily from toilets and is solid waste, this has to be handled in such a way that the solids can be settled out and removed and so bacteria can work to break down the stuff and render any pathogens harmless. Septic tanks and leach fields are great at treating black water from a sanitary point of view. Unfortunately, the nutrients that dissolve out are simply flushed into the soil and quickly find their way to waterbodies. Other sorts of treatment systems can be more effective. One recommendation is to use compost toilets instead of flush toilets.
Compost toilets prevent the harmful leaching of nutrients into the soil by composting the contained waste so it breaks down over time into dirt.
Composting toilets use natural biological decomposition to convert toilet wastes into water vapor, carbon dioxide, and a stable compost-like end product. The decomposition process is accomplished by aerobic (oxygen-using) bacteria and fungi. The complex population of microorganisms in the composting material make conditions unfavorable for the growth of disease-causing organisms which can be present in human waste. Pathogenic organisms die off or are consumed by the composting organisms as long as the composting process is proceeding normally and has adequate time to work.
(Source: Barnstable County Health)
When solid wastes are completely decomposed, the average person produces 2-3 gal (0.25-0.4 cubic ft.) of compost per year. The compost produced by a Clivus Multrum (the only system for which we have seen data) is approximately 2.5% total nitrogen and has a nitrogen:phosphorus:potassium (N:P:K) ratio of 2.5% N:3.6% P:3.9% K. This compares to garden compost with a typical N:P:K of 2.5:1.5:1.4 or composted sewage sludge at 2.1:2.2:0.3. Nitrogen levels in all are comparable (note that typical lawn and garden fertilizer has an N:P:K of 10:10:10). However, approximately 70% of the nitrogen in the Clivus compost is present as organic nitrogen. This form of nitrogen is bioavailable for uptake by plants and soil microorganisms but will not readily leach to groundwater.
(Source: Barnstable County Health)
Greywater is full of nutrients also (from sink, washing, shower, etc) but isn’t a threat for spreading pathogens nearly as much as with black water. So greywater can be treated more easily and reused for watering plants (which then can absorb much of the nutrients). The best way to prevent nutrients pollution waterbodies is to limit the ingredients you put down the drain. Shampoos, soaps, and cleaning products should contain no dyes, perfumes, or ingredients you can't identify. Non-toxic products abound (check out the links below).
Here are some links to help get you started thinking about handling greywater and black water differently:
- The “Bible” for understanding what is going on in lake water throughout New York is “Diet for a Small Lake” which can be found through the NYSFOLA website.
- Composting toilets: Nature's Headand Sun-Mar
- Greywater filtration systems – Amazon offers an easy-to-use greywater filtration system for less than $700 (click here)
- Living greywater treatment – one of many good articles describing ideas and plans for building your own living greywater filtration system is over at Eco Films
- Biodegradable soaps and cleaning products and how they should be used - Biogreen and Back Country Attitude have some great products available.