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The Six Great Principles of Ecological Sanitation

Water Supply

The first principle of sustainable water management is to adapt water quality to its end-use.

In a world where quality water is becoming rare, it’s unreasonable to persist in using expensively produced potable water for all domestic usages. This aberration nevertheless prevails, in spite of the numerous problems it has created worldwide. The standard for «potable water access» has become the faucet, which dispenses potable water throughout each household. In the present environmental context, extending this vision to all of the planet’s inhabitants involves financial investments that are beyond most countries’ capabilities.

Even in regions where this approach is financially accessible, its environmental impact remains excessive. As quality water becomes rare, producing legally compliant potable water becomes progressively more expensive. With water’s increased price, private water supply corporations can obviously increase their profits while disregarding the principle of universal access to water. Social policies will be called upon to compensate this breach, simply by transferring the added costs (totally unnecessary as far as we are concerned) to society.

To avoid this dead-end, the first step is to introduce the concept of « safe water » alongside that of « potable » water. The accidental absorption of small amounts of safe water can in no way be harmful to someone’s health, even without it being legally « potable ». For such water, you can downgrade standards in order to take into account non-food water needs. When considering our degrading water resources, production of safe water will be much less expensive than that of potable water. In some regions or cities where this situation is first likely to emerge [1], it’s more rational to give up on potable water distribution and rather prioritize safe water distribution. Thenceforth for drinking water, the population will have the choice between commercially sold bottled water and decentralized domestically produced potable water. In the latter case, to produce one’s drinking water, each will have the choice between purifying safe water or harvested rainwater, by filtration. Financial incentives can be implemented to aid those in need in acquiring the necessary equipment.

Unfortunately, the concept of « safe water » comes up against the concept of hygienics, which imposes potable water not only for drinking (less than 3% of our consumption), but also for personal hygiene, laundry and dishwashing. The fact that more than 700 000 people in Belgium have been using «safe», non-potable rainwater for years illustrates how absurd those requirements are.

The second principle is to create a legal and regulatory framework that provides fair and equal treatment to all available water resources.

Presently, the notion of equity is not honoured. The sale and distribution of potable water is reserved almost exclusively to a few public and private corporations. In some instances, like in France, regulations even prohibit using harvested rainwater within the home [2].

And yet, there can be no sustainable water management without total reuse of the precipitation that falls on building roofs. With this in mind, rather than regulate domestic rainwater use, it would be better to impose the installation of rainwater cisterns (backed with financial incentives). Those who realize new building constructions or major renovations should be prompted to install a cistern that is sized with respect to the home’s roof area (i.e. water catchment capacity). For some odd reason, water technicians encourage the installation of cisterns that are too small. On rainy days, much of the water in such cisterns is lost through the overflow, water that would otherwise be needed during dry spells. Theoretically, 60 to 80% of household water needs could be provided by rainfall harvested from roofs (in Western Europe).

Authorities should admit of the principle by which everyone can become one’s own drinking water producer (either from harvested rainwater or from a well, for example), without however imposing quality standards. This obviously doesn’t prevent authorities from issuing recommendations and advice.

With such simple and really inexpensive measures, the strain on our water resources would be substantially reduced. This approach has a good chance of being less costly to society than centralized water distribution monopolies.

In addition, a more generalized use of properly harvested rainwater (naturally fresh, weakly calcareous) also has an impact on wastewater’s pollution load and on the soil’s moisture regime in urban areas. One can therefore understand the mutual dependence between water supply and wastewater treatment[3].

Urban Wastewater Treatment

The third principle of ecological sanitation is tied to the prevalence of wastewater discharge, whereby we must avoid as best we can the discharge of treated wastewater into surface waters such as rivers or lakes, while making maximum use of soil’s and plants’ remarkable (and free) purifying capability.

This option can seem difficult to implement in an urban context. Yet, when you consider the enormous costs involved in current wastewater collection, conveyance and treatment, the inception of policies that integrate this third principle could have brought about urban ecological sanitation at a cost comparable to, and even less expensive than the conventional approach [4]. Furthermore, as an added benefit, cities would effectively have ceased polluting surface and ground waters. And let’s not forget corollary energy savings and ecosystem remediation.

It’s therefore imperative to define differential discharge standards, between surface water discharge and infiltration (dispersal) in the ground.

Another point that follows from the fourth principle consists in defining discharge standards for grey water only, without black water. The implementation of these standards would drastically reduce purification costs in rural and suburban areas [5].

The fourth principle consists in selectively treating grey water. Grey water and black water must be collected and treated separately. For black water treatment, one must resort to the BLT (biolitter toilet) principle.

From a scientific point of view, the « all to the sewer » system is just as absurd as our « throw-away » society of « all to the garbage » consumerism. Black water’s and grey water’s respective characteristics are so different that their selective treatment is self-evident. In addition, black water’s pollutant load is not a waste that needs to be destroyed, but is a precious raw material for the biosphere’s safeguard.

Unlike what some may think, applying the fourth principle in itself doesn’t oblige dry toilet use in urban zones. It simply means that grey water must be collected and treated separately from sewage. As it contains no metabolic nitrogen or phosphorus, grey water’s treatment becomes quite simple when compared to mixed wastewater. When done in respect of the third principle, grey water could simply be dispersed in soil [6], without the least harm to ground waters [7].

Before being discharged in the closest watercourse, grey water from large cities would be conveyed to landscaped wetlands specially established in peri-urban zones (urban-rural fringes). Sole grey water behaves quite unlike conventional urban wastewater. Daylight and atmospheric oxygen obliging, such wetlands will eliminate the entire pollutant load (remember: there’s no nitrogen) by process of coagulation, followed by flocculation and sedimentation. Bacteria will go the same route to end up at the wetland bottom as sludge while many will simply be eliminated by the sun’s UV. Based on experiments carried out at Université de Mons in Belgium, water that issues from such wetlands contains less nitrogen than what can be found in mains supply water. Thus, by creating wetland reserves specifically for grey water purification, you get the additional benefits of creating natural reserves and stopover sites for aquatic migratory birds. The portion of the wetland situated just before discharge into a watercourse could become a recreational park area.

The fifth principle is that of the BLT. Human (and animal) dejecta must absolutely not be discharged in any way into water. They must be treated, in the form of a concentrate, jointly with plant-based cellulose « waste » to generate humus for soil.

To treat our dejecta while abiding to the BLT principle, the biolitter toilet is the preeminent way. In rural and suburban areas, the use of dry toilets is technically possible, providing as much convenience (although in a different way) as a conventional flushable WC. In such areas, composting in gardens or yards (i.e. « back yard » composting in Canada and the USA) should ultimately become the rule, once mentalities will have evolved. In the meantime, one could implement a program in selected neighbourhoods for the pick-up of fermentable garbage, including garden trimmings, kitchen scraps, and dry toilet effluent. Nevertheless, this is an expensive and somewhat unreasonable solution. The decision to inhabit such neighbourhoods should ultimately be tied to an obligation to compost one’s own fermentable waste. This is much simpler and less constraining than what some people think.

In urban areas or high-density housing, the biolitter toilet would be replaced by a new type of toilet that I have coined the turbo-toilet, or TT. It would resemble those toilets found on trains or airplanes, with a high-pressure flush that would deliver very little water with each flush. This is necessary to avoid diluting the dejecta, in the interest of ulterior treatment based on the BLT principle. TT’s would also come equipped with grinders to liquefy the effluent and facilitate its evacuation. The liquefied TT effluent would then be conveyed in a separate collection network towards a litter impregnation and composting facility.

Important Notice:

The TT does not yet exist, but its operational principle is known and well experimented. Its elaboration is simply a question of adapting the WC to tried and tested techniques, as described above.

The sixth principle sets the conditions for combined treatment of waste. It is also tied to our energy problems, and as a consequence, to climate change. All nitrogen-based (animal) and carbon-based (plant) biomass contained in our waste must be mobilized towards their combined simultaneous treatment, to ultimately return them to soil in the form of humus.

Ecological sanitation extends far beyond the field of sanitation engineering. Or rather, tomorrow’s sanitation engineering should integrate remediation of the world’s degraded ecosystems in its goals.

Litter-impregnation facilities for black water will become hubs for urban biomass management. In effect, they will constitute the main source of nitrogen- and phosphorous- based organic soil amendment for agriculture.

To supply our nitrogenous animal-based biomass, we will dispose of concentrated black water from urban turbo-toilets, liquid pig manure from industrial pig-farming facilities [8] and the fermentable part of urban waste.

For our carbonaceous plant-based biomass, we will dispose of the cellulose component of household waste (soiled paper, cardboard packaging, and all paper waste that is inappropriate for recycling as paper), shredded plant waste from city park and tree maintenance, seasonal leaf and garden waste collection, shredded wood pallets, boxes, cardboard, etc. In need, you can also include waste from wood mills (bark and sawdust) and carpentry shops (wood shavings).

[1] For example, in some coastal regions where water tables have been overexploited, seawater has penetrated underground drinking water reserves. The solution proposed by water distribution companies is to treat water by nanofiltration, which eliminates part of the water’s solutes. This solution is expensive.

[2] In France, legislation prohibits the technical basis for properly harvested rainwater. The new law does not authorize cistern materials that react with water, thus preventing the use of concrete and masonry cisterns. Yet, it’s precisely with these materials that you instil rainwater’s primary treatment to neutralize its acidity. As a consequence, when using plastic or stainless steel cisterns as imposed by law, rainwater rapidly becomes putrid and unusable, not only from lack of neutralization, but also from the absence of dissolved minerals.

[3] There is a direct link between rainwater harvesting and a household’s wastewater pollutant load. Thanks to rainwater’s almost total lack of calcium carbonate content, homeowners who use such water for cleansing and household cleaning will use 30 to 60% less detergent than what is required by mains water supply, which is very often hard water. Much of these detergents transits through sanitation plants. Reducing detergent use at the source represents a substantial gain for watercourse quality levels.

[4] And yet, since the 1990’s, I have regularly explained the above proposals to the Belgian government’s Walloon Region Water Advisory Committee. Ecological sanitation would have satisfied all of the European Community’s requirements, while reducing costs and ensuring environmental protection far exceeding conventional techniques.

[5] This is particularly true of unjustified prohibition of absorption pits (inexpensive set-ups) even when considered for grey water infiltration only. Many dry toilet users only generate grey water. Yet, their request to install an absorption pit to receive grey water that has been pre-treated in a batch reactor is systematically denied, even when the quasi-absence of nitrogen in digested grey water guarantees null impact on ground waters.

[6] To prevent a dispersal system’s clogging, water must first transit through a grey water batch reactor where it will undergo spontaneous anaerobic fermentation (or digestion).

[7] Except in flood plains, where the water table is too superficial, or in a soil with lots of fractured rock. In such cases, grey water must absolutely be treated by anaerobic fermentation, followed by particle filtration through a planted trench filter (0,5 m²/IH) and a wetland finish treatment (1 m²/IH). Crystal-clear water issuing from such a system often complies with potable water standards.

[8] In a foreseeable future, industrial livestock raising will have to adapt to sustainable agriculture imperatives. In the meantime, one possible venue is the generalized application of deep-litter livestock housing systems, which in effect is the transposition of the fifth principle to livestock raising.

To continue reading, go to Components of Ecological Sanitation

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