ABSTRACTS

Open Doors at the Pilot Greenhouse Ruswil, Switzerland, on October 2, 1999

By: Brigitta Züst, Centre for Applied Ecology Schattweid, Switzerland

The greenhouse utilizes surplus heat generated by a compressor station situated along a major European pipeline for natural gas (see also ECOENG NEWSLETTER 1/1999).The amount of available surplus heat is about 55 000 MWh per year. It will be almost 6 times more when the transport capacity has been increased. The Swiss law stipulates that this surplus energy must be used. The 1500 m2 greenhouse will be heated with the low energetic part of the surplus heat while the high energetic part of the heat will be transformed into electricity.

The greenhouse presently comprises three sections: aquaculture, a tropic fruit and a subtropic fruit and vegetable plantation. The aim is to economically produce interesting fruit and vegetables as well as fish in polyculture systems by reusing nutrients and energy repeatedly at different levels. The products are not to compete those of local farmers and gardeners.

In the tropical section papayas, cumquats, bananas, mangos, caramboles grow. The tropical fish Tilapia are also bred in the tropical section, as well as water lentils and water hyacinths. The subtropical section houses cherries, melons, pears and others.

The goals for the first year are:

• to improve the heat supply
• to optimize both earth and aquacultures
• to minimize the occurrence of pests and if there are pests to fight them with as natural means as possible.
• to draw up an energy balance as soon as possible

Studies are done in conjunction with the College of Engineers at Waedenswil. The project is supported by the company running the gas pipeline (Transitgas AG) who financed the greenhouse and a community of interests of local farmers, shop owners, private persons who supervise the everyday running ot the greenhouse. Research is supported by the Swiss Commission for Technology and Innovation.

Dissertation on Purification Function of Wetlands in the Liaohe Delta, China

By our Chinese correspondent Li Xiuzhen, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China

The Liaohe Delta is located in Northeastern China, to the north of Liaodong Bay. The climate is temperate monsoon, which is hot and flooded in summer, cold and dry in winter. The 100,000 ha reed marsh here numbers the world second largest. The human management regime of annual irrigation in spring and harvesting in winter enables us to use this vast wetland as a control system for nutrient enriched river water. By integrating processed-based mathematical models with GIS, a number of results and conclusions have been obtained through this study.

A spatial simulation model has been established based on the field and literature data, to simulate the nutrient reduction and its distribution in the wetland. A non-linear regression model is used for the nutrient reduction in the canal system, while Mander-&-Mauring’s linear regression model is adopted for the reed fields.

According to the simulation result, the total reduction rate is about 66% for total nitrogen and 90% for soluble reactive phosphorus. In combination with the canals, the present 80,000 ha of reed can remove about 3,200-4,000 tons of nitrogen and 80 tons of soluble reactive phosphorous during the irrigation period each year. But this is only 1/10 of its total reduction capacity, with water being the limitation factor.

Four spatial combinations of reed, canals and pumping stations are designed to investigate the effect of pattern on nutrient reduction: 1) canal density, 2) reed area size, 3) reed shrinking pattern and 4) pumping station position. The simulation results indicate that each factor brings less than 10% deviation in total nutrient reduction rate, though the absolute reduction quantity can be different. If the reed area is stable, it is better to remain a low canal density, and keep the pumping station near the border of the reed area. Generally speaking, smaller reed area close to the pumping station is more efficient in nutrient reduction than larger, scattered ones. The shrinkage pattern of land transformation for the reed is most recommended in keeping a high reduction rate for the nutrients. The present reed area can accept at least 4 times more water in spring.

The research work is a combination of landscape ecology, wetland ecology and GIS technology. The spatial model developed is also applicable for other areas with similar situations. The results will contribute to a sustainable landscape planning in the study area.

LI Xiuzhen, 2000. Purification function of wetlands: Spatial modelling and pattern analysis of nutrient reduction in the Liaohe Delta. ISBN: 90-5808-165-6. Wageningen University, the Netherlands.

Sustainability and Liberalization in the German Water Sector - a Workshop Report

By Andreas Schönborn, Switzerland

The workshop was dominated by two main topics:

• the term sustainability and its definition in the context of water industry
• the liberalization of the German water market

There was no consensus on sustainability. Some claimed that the German water industry is already sustainable because it heeds the so called "1st Management Rule" (Don't take more water from nature than is replaced in a medium-term). Mr. E. Schramm from ISOE denounced this rule as inadequate and highlighted the non-linear nature of ecosystems. The belief was expressed in the audience, that todays decentralized, community-owned structures are favorable for sustainability. Others objected that the sustainability of these structures has never been proven. Some delegates even doubted the possibility to reach consensus on sustainability criteria at all. In any case, the term "sustainability" remains "spongy" and thus is in danger of being instrumentalized by interest groups, as Mr. W. Kahlenborn pointed out.

The situation was confused by the fact that German water industry - so far a highly regulated sector - is on the brink of liberalization. There seems to be considerable unease, especially among the representatives of the water works, as to what this liberalization will bring. Mr. P. Heymann of Deutsche Bank claimed in his presentation that "water will become a homogeneous good, like electricity and will be traded freely in the future". This implies that one can achieve homogeneous water quality with a "handful of chemicals" (Heymann), because the water would have to be treated for transport. From a water quality point of view this is a "step back to the sixties", as one delegate said.

Whereas the changes liberalization will bring for the German water industry are beginning to become visible, the consequences on ecological criteria remain in the dark. There was consensus that liberalization must be accompanied by research. At the end of the meeting a number of research goals were identified.

Although the original question of the workshop was not answered, the good choice of speakers, the broad based audience and the high level of the discussions made it a workshop worth while attending.

Contact ISOE: http://www.isoe.de

Present State of the Otelfingen Aquaculture Pilot Project

By Jürg Staudenmann, University of Applied Sciences, P.O. Box 335, CH- 8820 Waedenswil

The multi-step aquaculture consists of a cascade of basins (surface area 10 m2, 0.5-1.5 m deep), arranged in different modules along the nutrient concentration gradient with distinct environmental parameters and organisms. Beside water plants well-known for wastewater-fed aquaculture in Asia, such as water hyacinth (E. crassipes), duckweed (Lemna spp.), or water lettuce (Pistia stratiotes), several indigenous plants have been introduced into the system. Further on, experiments with different algae and zooplankton strains, as well as fish stocking have been conducted. First results were very promising, although the specific factors of the temperate climate were much more challenging for the operation of the system, compared to traditional Asian sites.

Integration of ecological structures along with appropriate technological tools lead towards a "semi-tech ecological engineered system" (Staudenmann & Junge, in press). To determine this fragile balance between ecology and so called high-tech played a major role in planning and designing the research facility. The main goal for the performance of the plant is to achieve high recycling rates for the nutrient load and to grow valuable aquaculture products. This aim is prioritized over treating the wastewater to achieve national effluent standards. Nevertheless, the high concentrations of both inorganic and organic compounds in the biogas-plant effluent (TOC, NO3-N, NH4-N, and Total-P concentrations being 670 mg/l, 150 mg/l, 95 mg/l, and 50 mg/l, respectively) was reduced by 90-95% in the outlet.

In 1999 the site has been enlarged and new modules have been designed. The biogas-plant effluent is now additionally used as liquid fertilizer to produce vegetables using newest production methods (natural and artificial rockwool soils). It appears to be a perfect medium for particular cultures, especially when applied directly to the plants roots. The challenge at present is to achieve the ideal combination of both horticulture and aquaculture modules, in order to profit from potential synergic effects. Further on, new and convincing selling strategies for different products of the Otelfingen Aquaculture Pilot Plant at Swiss market conditions must be developed.

Contact: Ranka Junge-Berberovic, University of Applied Sciences Dept. Horticulture / Aquaculture P.O. Box 335 CH- 8820 Waedenswil, Email: r.junge@hswzfh.ch
Info on the aquaculture: http://www.hswzfh.ch/horti/aquakultur/index.htm
Info on Kompogas: http://www.kompogas.ch

Literature:
Staudenmann, J., Junge-Berberovic, R. (in press). Treating Biogas Plant Effluent through Aquaculture: First Results and Experiences from the Otelfingen Pilot Plant (Switzerland) after one Year. Proceedings of the 6th Int. Conference on Ecological Engineering 1998, Calcutta India.

Ecological Engineering News From Aotearoa/New Zealand

By Andrew Dakers, Christchurch, New Zealand

It is summer in Aotearoa/New Zealand and most of us had hoped for nice warm and sunny holidays and a cloudless sunrise to welcome in the new millennium. At the same time we curiously anticipated Y2K confusion and disruption. Neither has happened - yet. We probably won’t really know whether it is human induced climate change that is causing somewhat unprecedented bleak summer weather or if it was hyped up commercial opportunism that overrated the potential chaos of the Y2K change-over.

At the end of 1999 New Zealanders voted in a new coalition government resulting in a record 7 green politicians into parliament. Two key issues the greens campaigned on were opposition to genetically modified food and the logging of native trees by a large state owned enterprise. We are hoping Ecological Engineering finds a creative and constructive home in this new political environment.

IEES Conference. November 2001

In mid 1999, a group people had some initial series of discussions to plan the November 2001 IEES conference in Christchurch. Now that the holiday season is over, organisation of the IEES conference is back on the agenda.

Student Projects

Canterbury University School of Engineering, in co-operation with the Environmental Management and Design Division of Lincoln University offer a Bachelor of Engineering in Natural Resources Engineering. As a requirement of their final professional year students are required to complete a major engineering project.

Several projects last year embraced some of the principles of EE, but with engineering foci. One project was to set up some controlled environment trials for different wetland plants that may be suitable constructed wetlands for wastewater treatment. The purpose of the project was to compare Phragmites australis with some of NZ’s native wetland plants e.g. Typha orientalis. In terms of the Biosecurity Act Phragmites australis is a restricted plant in NZ. A recent legal application failed to gain a exemption for its use in a constructed wetland to treat a rural town’s wastewater. The project will continue this year.

Urban Ecology - a network for Southern Countries

Within the programme at the recent Southern Connection international conference help at Lincoln University, (17 to 21 Jan 2000), a series of papers were presented on Urban Ecology, including a paper on the role of ecological engineering. As a consequence a group of enthusiastic people, representing a number of disciplines and countries (e.g. Australia, South Africa, South American and NZ), met to form a network and to explore possibilities of joint projects and collaborative research. It was decided to set up a communication network and a webpage. When it is set up I will report the details. Ecological engineers have much to contribute to initiatives in urban ecology.