Water saving technologies to reduce water consumption and wastewater production in households
In a many postings, reports (www.backlund.dk) and lectures (Slideshare) I have for years been focusing on linking ecological sanitation and agroecology advocating returning human nutrients and organics from plate to soil and farming questioning conventional understanding, concepts and system approach to waste and wastewater streams.
Here the focus will be on water saving technologies to reduce water consumption and wastewater production in households.
Working in developing countries like Uganda with very limited access to clean and safe water is one thing and working in developed countries like Ireland and Denmark with much more priviliged access something else.
So positive to see rain water harvesting develop and grow in developing countries like Uganda and at the same time so depressing to find almost newly installed out dated extremely bad functioning flush toilets consuming so much of the harvested water to flush out faeces and toilet paper.
Even in Ireland known for large and frequent all year round precipitation and great access to very cheap drinking water best ways to reduce water consumption and wastewater production in households are of interest among others to reduce wastewater ammount to be treated and disposed of.
It has been a great pleasure to contribute to this work in Ireland
"Typical on-site wastewater treatment systems for single houses in rural areas with no mains drainage consist of septic tanks and/or package treatment plants followed by a percolation area (soil attenuation system). If the subsoil permeability is not sufficient to take the effluent load, surface ponding may occur with associated health risks and a risk of runoff of pollutants to surface water".
Water saving devises such as waterless toilets, waterless urinals, ultra low or low flush toilets, vacuum toilets, low-flow shower heads and low-flow taps efficient dish washers and washing machines will reduce wastewater production and hence hydraulic loadings on percolation areas improving the functioning of the soil attenuation system minimising surface ponding and runoff.
It has been so interesting contributing to combine work on water saving technologies to reduce water consumption and wastewater production in householdsto with investigations on options to implement our danish speciality "On-Site Zero Discharge Willow Wastewater Evapotranspiration Systems" in Ireland shows the importance minimizing wastewater. In Denmark I have had the pleasure for 30 years investigating systems, checking plannings and advicing municipalities and counties about suggested systems with different assumptions, layouts, dimensioning and concepts related to expected present and future conditions.
In Germany the options for testing and showing were also given among others in Hannover.
Fertigating food crops or non food multifunctionel short rotation energy willow plantationare other areas where water savings and more concentrated nutrients are important.
In Denmark we also have access to cheap and relatively clean and safe drinking water. Wastewater charges are relatively high and focus on reducing water consumption are relatively high. Household water consumption in Copenhagen is about 100 litres/p/d with 3/6 litres low flush toilets as standard - and some places like the famous Rooftop farm "?stergro" with the restaurant "Gro Spiseri" even with EcoFlush Ultra Low Flush water saving toilet.
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In among others EcoVillages in Denmark like Karise Permatopia a lot of drinking water is saved by harvesting rain water to be used in washing machines and 96 EcoFlush Ultra Low Flush Diverting toilets. In Permatopia the value of reducing water consumption and "wastewater" production is high as they combine EcoFlush and diverted streams with a large common "On-Site Zero Discharge Willow Wastewater Evapotranspiration System" taking advantage of minimizing hydralic load. Dimensioning systems re surface and volume is related to present and future expected precipitation and hydralic wastewater load - and water savings and wastewater minimizing devises and handling are very important.
Enabling anaerobic processing - Minimizing wastewater production concentrating organics is also very important in rural areas with closed collection tanks to minimize emtying intervals and to increase concentrations to further handling among others to produce biogas. In projects and testing among others vacuum toilets have been considered and tested.
If warm conditions a household toilet can even be connected directly to the individual biogas system.
Aerobic processing - Composting -again many options to go from ultra low flush to collection and composting.
Here just one of many - from New York.
Finaly some work overcoming challenges with devices reducing water consumption transporting more concentrated substances in conventional piping systems.
Work developing extremely low faecal flush toilets - "EcoVip" and "Clever" releasing a "wave" with 0,5 litres of water + collected faeces and toilet paper failed 20 years ago.
But I have not given up the idea of pipe transporting material from very water saving devices by building up potential for releasing a wave - but this time not in the toilet but after the toilet collecting all or some streams in the household in a eg. 12 litres collecting and releasing unit. This would then even open up options to better work without electric pumps in On-Site Willow and others waste water treatment systems.
I am looking forward with Backlund Ecology to go on cooperating with among others authorities and companies in many countries developing and implementing water saving technologies to reduce water consumption and wastewater production in households - just let us know :-)
And finally and not to forget - if possible and acceptable or to make acceptable waterless sanitation - toilets and urinals are the most water saving options :-)