Les Assises HQE (Haute QualitÉ Environnemental)
24 - 25 November 2003, Bordeaux
Title: Conception écologique: Visions and Réalités
AUTHOR:
Dipl.-Ing. Harald Kraft,
Schmiljanstraße 7, 12161 Berlin.
Tel.: +49 - 30 - 851 66 16 / 85 96 11 94
Fax: +49 - 30 - 852 23 95
E-mail: kraft@ib-kraft.de
Introduction
In Germany in the 80’s we had a very innovative phase concerning ecological housing and water management. Various experimental projects had been executed including decentralised waste water treatment and reuse. In the early 90’s the access to waste water was blocked through the influence of the various lobbies. Fortunately this lobbies did not show much interest in dealing with storm water.
Until the mid-90’s, all storm water was treated as contaminated surface runoff and diverted away in drainage systems. Drainage took precedence over infiltration. However, with the amendments in the state water laws, the water resource management objectives became reversed, and decentralised infiltration began to take precedence over drainage.
Storm water management in urban areas is basically subdivided into that for private plots and that for public property, including streets public squares, parks, or other open areas. It is primarily carried out through retention, reuse, and infiltration. Drainage of storm water as wastewater can now be seen as outdated. Storm water management intended to relieve the sewer network, infiltration to enhance groundwater recharge, and on a limited scale, the storm water collection for reuse, are finding increasingly more application in modern development projects.
In recent years new water management and treatment technologies have been developed and demonstrated in projects. This is true especially for singular concepts using either rainwater management technologies or wastewater treatment in different locations. No experience exists in the operation of integrated decentralised installations including the potential for energy generation. The goal of the recently initiated research on ECOSAN (ecological sanitation) is to gain experience in comprehensive design and implementation of singular technologies aiming at quasi-autark concepts requiring only a minimum of public water, waste and energy management services. These concepts should prove to function in different types of settlements and urban structures as well as in various regional conditions and demands.
The Early Integrated Water Concepts
(1) Project Vijayanagar Steel City, India
The French architect, Roger Anger, designed in 1978 the VijaYanagar Steel City in India, which was to accommodate a work force of up to 250.000 people in a new steel plant. The city was located in an area that is almost a desert, next to a village that is about 3500 year old and the only source of water was an irrigation channel that flowed nearby.
The architect had visualised a green city as well as a large lake - a tropical beauty with an abundance of water. The provision of water for this venture proved to be very challenging. To meet the water demand the treated wastewater had to be reused for irrigation within the new city as well as in the ancient village. During the study of the masterplan all problems of the water supply had been solved, except the problem of hygienization of the treated wastewater.
At that time there was no technical option available to remove the pathogens from the effluent. During that time the German botanist Dr. Kathe Seidle had observed that macrophytes where able to remove pathogens from wastewater and she had designed the first treatment plants using reeds and bullrush.
During five years of research in the Technical University of Berlin the author developed a root zone treatment plant, to treat wastewater up to the EU standards of bathing water quality. The technology became the base for the treatment of wastewater as well as stormwater in the following projects.
(2) Project Broendbystraße 40, Berlin Lichterfelde
In 1985, the Berlin project “Ökohaus Broendbystraße 40” implemented, among other ecological technologies, a system of storm water harvesting and waste water treatment by means of a clivus multrum compost toilet (for toilet and organic household waste) and a root zone treatment plant for the grey water (10 PE). The treated effluent is reused for irrigation and the balance is discharged into an open water course. This system continues to be successfully operated today with very satisfactory results. (Architects: Ökohaus)
(3) Project IBA Block 6, Berlin-Kreuzberg
Within the framework of the Internationale Bauausstellung (International Housing Exhibition), Berlin 1987, a pilot project in the area of experimental housing and town planning, with a strong ecological emphasis, was to be implemented in Block 6 under the auspices of the Federal Ministry of Regional Policy, Building and Urban Construction (Bundesministerium für Raumordnung, Bauwesen und Städtebau).
The objective of this demonstration project is maximum conservation of water resources through measures of reducing the drinking water consumption and environmental pollution caused by waste water. The rainwater was harvested in a rainwater pond.
The domestic sewage of 73 apartments in this pilot project is pumped from a collector pit outside the building into a root zone treatment plant for biological treatment. Research on the performance of the treatment plant has shown a reduction in the pollution load to below the standards of bathing water quality (of the EC), as well as successful reuse of the effluent for irrigation and toilet flushing. This project has received an award from the President of the Federal Republic of Germany in a national competition. (Landscape Architect: H. Loidl)
The present design of Ecological Sanitation
(9) Project B31, Reinbek – “Living Space”
The project area of 4,2 ha offers the space for about 200 people in 40 - 50 flats. (Architect N. Roderjan, Landscape Architect: R. Herms)
The project will demonstrate new concepts, technologies and products for minimising wastewater, separation of faeces, urine and water and reusing treated wastewater. Furthermore the potentials of reuse of rainwater can be demonstrated. The decentralised generation of electricity and heat will include the use of organic wastes and leftover wood from logging activities.
The project comprises of the following elements:
1. Drinking water supply by rehabilitating the existing deep ground water well on the site,
2. Minimising wastewater by modern sanitation technologies (separation toilets, dry toilets, separation of urine and faeces, urine will be used for soil improvement)
3. Remaining wastewater being treated at the treatment plant on the project site (anaerobic treatment of sludge, rootzone treatment) for reuse in irrigation.
4. Rainwater run-off collected in a pond and in a balancing tank for drinking water substitution for toilet flushing, washing machines and for groundwater recharge.
5. Anaerobic treatment of organic waste, use of methane gas and sludge from waste water treatment for energy production.
6. Block heating and power generating plant that produces energy from renewable resources (methane gas, wood pellets, solar energy)
(10) Project “International City of Auroville”, India
The International City of Auroville is designed by the French Architect Roger Anger. This township is to inhabit 50.000 people within a circular area with a diameter of 2,5 km, and be surrounded by a 1,25 km wide greenbelt.
The geographic centre of the township is located on a gentle hill, 52 m above sea level, 5 km from the coast of the Andaman Sea, and 200 km south of Madras. When the first settlers arrived, the hill was devastated by centuries of deforestation. Huge gullies had been caved out. The land had been cleared and the red earth was exposed to the torrential monsoon rains. The construction of Auroville began in the centre, which is to be created into a park with a spherical building, 30 m in diameter, an amphitheatre, and an old banian tree surrounded by a large lake.
In the early 1970’s, the place was not fit for human life, with no shade and no water. The first settlers had to control the erosion by “bunding” and reforestation, as well as provide the basic infrastructure and water supply. This has just recently been achieved. In the meantime, the population in the surrounding areas has grown, along with their ability to extract groundwater. Since the early 1990’s, sea water intrusion into the coastal aquifers has been reported.
Under this threat, an alternative water management scheme was developed by the author in 1992 in order to safeguard the very existence of the city. It is planned to base the entire water supply on the precipitation. The rain water is to be harvested from the roofs and stored in cisterns. The remaining surface runoff, including that from the roads, is to be captured and stored in large reservoirs within the greenbelt. After purification, it will be lifted up to the large central lake.
After further purification in the lake, the overflow will be infiltrated beneath the park into the first aquifer which lies above sea level. From there, the water can be tapped by wells throughout the city. The harvested storm water is not sufficient to meet the full demand for irrigation.
Therefore, the entire waste water has to be treated to meet bathing water quality standards and reused for the irrigation of agricultural lands within the greenbelt.
The Future
The present development is towards the autarcic building in a city without sewers and pipes. The future buildings and cities shall be designed by architects with a vision. The realisation of these visions shall be the task of the engineers.
The materialisation of these visions require politicians, mayors and developers who can visualise the future and who can make it become a reality.