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FAIR-CT97-3947
BWCW: Biomass short rotation willow coppice fertilized with nutrient from municipal wastewater |
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Proposal No: | FAIR-CT97-3947 |
| Date Prepared: | April 1999 | |
| Source: | Third Annual Progress Report
First Annual Progress Report |
Objectives
This project concerns an integrated investigation to provide an EU-wide (from northern to southern Europe) scientific basis for growing willow coppice for bioenergy production using municipal wastewaters rich in plant nutrient (substituting commercial fertilisers). A simultaneous environmentally acceptable, safe from the sanitary aspect, and economically feasible disposal of the wastewaters into the willow plantations, leading also to elimination of river, underground, and coastal water pollution.
Two main objects for this study are a) the vegetation and b) the wastewater. Willow coppice is the vegetation which has to purify the water and produce bioenergy. The wastewater to be cleaned is a municipal wastewater or a wastewater from the food industry (with low content of heavy metals) which has been mechanically filtered and biologically treated in a secondary treatment step or lagooned in open ponds before it is used in the plantations.
Activities
The work will be carried out in a period 50 months by six participants with significant experience obtained through many years of research on biomass production for energy uses and on wastewater treatment. Plantations were made in Northern Ireland in May 1998, in Sweden in May 1998, in April 1998 in France and in March 1999 in Greece. Drip irrigation systems are used on three sites, Sweden, France and Greece. A sprinkler system is used for the experimental plots in Northern Ireland. All systems have automated regulators. The supply of water is calculated according to the local climatic conditions. Climatic data are continuously recorded throughout the project period to be used to adjust the supply of water to the trials. A storage tank for humane urine has been placed underground close to the experimental field in Sweden. Irrigation to the experimental plots for urine works parallel to irrigation with wastewater and is regulated automatically.
Studies of growth and biomass production are made under five different treatments. These treatments include three different wastewater irrigation rates, clean water irrigation and one with humane urine (only on one site in Sweden). In each field experiment twelve/eighteen subplots (four/six treatments, three replicates) have been established with appropriate distance between the subplots, in order to avoid border effects. Samples of, soil, soil water and biomass are taken in the centre of each sub-plot.
The effect of treatments on all these growth characteristics and biomass yield variables are analysed and correlation's with soil and groundwater analysis are made. An overall- analysis of the four experimental fields have also been carried out so that a EU-Wide evaluation of the wastewater irrigation system can be presented.
Progress
Plant material. The SW-variety Jorr was used in all trials.
Irrigation. The schedule for irrigation are different for each site depending on the local climatic conditions. The PE (potential evapotranspiration) is calculated for each site and the supply of water is given according to that. The supply of water to the experimental plots is made by drip irrigation in Sweden, France and Greece (under soil surface) and by sprinklers in Northern Ireland.
Human urine. Three of the 18 experimental plots at Roma-kloster are aimed for the urine trial. A tank for storage of humane urine has been dug close to the experimental field. The urine is delivered from an adjacent school.
Biomass. Biomass measurements have been made in all trials during last winter. There are more clear differences in biomass production this year between the different treatments than during the last year. Highest biomass growth are observed in 2 x PE and 3 x PE, with about 8 to 13 tonnes dry matter per hectare per year. The average yield has increased from the last season in the trials in France, Sweden and Greece, but has gone down (except for 3 x PE) in the trial in Northern Ireland. The biomass estimation for urine treatment was as high as 13,2 tonnes. The effect of water and nutrients from the wastewater is expected to rise the biomass production to considerable higher levels compared to plantations without irrigation, This is one of the positive effect of the technique. The final yield after three year growth (in Greece two year growth) will be estimated by weighing at the end of this year.
Clonal trials A small variety screening trial has been established at the field site in Northern Ireland in June 1999 to find clones/varieties more suitable for treating wastewater. In March 2001 biomass estimations were carried out on the small clonal trial established at the field site. Final test will be made during 2001. Chemical components in biomass. The main part of the chemical analyses of the plant tissues will be taken at the end of 200 1, when the plantations will be harvested.
Soil sampling. Initial analyses of the soil texture and chemical composition have been made from all four experimental sites. New soil analyses will be made at the end of the project period for comparison to the initial ones.
Groundwater levels and analysis. The level of the groundwater table is very much dependent on the local climatic conditions. In Greece in Dec 2000 the groundwater table was as low as 7.0 m, which made it impossible to collect soil water for analyses for that period. Chemical analyses of the groundwater has regularly been made during 2000 from all sites. Final conclusions about the distribution of nutrients and other chemical substances within the system will be analysed at the end of the project period, when data from soil, biomass, groundwater and applied wastewater will be modelled together.
Wastewater and clean water. The types of wastewaters vary significantly between the sites. In Greece and Northern Ireland the effluent comes directly from a treatment station and has a relatively high content of N, about 35 mg/l in Greece and about 20 mg/l in Northern Ireland. In Sweden, where open ponds are used for pre-treatment of the wastewater, the content of N has been reduced a lot before it is used for irrigation in the trial. The level is as low as about 3.8 mg/l. The amount of N in clean water (1.7 mg/1) is not much higher in the wastewater at Roma-kloster. The clean water in Northern Ireland is at about 2.5 mg/l and at similar level in Greece.
Economics. An economical analysis has been made of treatment of leachate water from a landfill by using willow (a close parallel to treatment of wastewater from municipalities). Results show that facility leachates can be purified at roughly half the cost (3.8 SEK per m3 ) compared with that of conventional leachate treatment at a wastewater treatment plant (6.5 SEK per m3 ) . Treatment costs are further reduced to 3.6 SEK per m3 of leachate when the revenues from the sales of the biomass chip market are taken into consideration. Analysis also shows that, because of the large leachate holding pond expense, not all facility leachates should be treated through a vegetation filter. Furthermore, it was shown that the revenues from the sale of the biomass chips are only a small factor in the overall cost of the purification technique. The most important component being the conventional leachate treatment cost offset at the treatment plant.
Social aspects. It was planned to start the study covering the social aspects of treating wastewater with vegetation filter during 2000. However, will now start in mid 2001.
Legal aspects. A translation (in a draft) of the earlier made work on legal aspects is now available.
Sanitary aspects. The results from the baseline investigations made in three willow/wastewater plantation in southern Sweden (tracer-studies, faecal dropping studies and site specific assessment from two sites in southern Sweden) have been followed up during year 2000 by study of samples from Roma-kloster, Culmore and Larissa. During 2001 the baseline investigation will be followed up with supplementary samples of wastewater, groundwater and faecal stools from the different areas. The aim is to make a comparative risk assessment between the various sites.
Environmental aspects. Leaching estimates will be made of various elements for the three consecutive years of the project. A method using chloride as a non-reactive tracer will be the main method applied, but the method will be validated using leaching estimates based on water balance. Preliminary estimates will be made during 2001 and the final estimates will be made during spring 2002.
Biological aspects. Leaf samples, for assessment of rust infection, were taken at t e French and Northern Irish field trials at the beginning of July, August and September 2000 (to allow for the calculation of cumulative rust scores); and at the beginning of August and September at the Greek and Swedish field trials. There was almost no rust present on the samples from Greece and Sweden. Rust scores were higher at the French trial than the Northern Irish one, but lower at both sites than in 1999. For both these sites, although there was some indication that rust infection was greater in the higher wastewater irrigation treatments, when the results were statistically analysed there were no significant differences between treatments.
An infestation of black willow aphid (Pterocomma salices) in the trial, and the occurrence of stem die-back in the plots, were monitored and assessed during the 2000 growing season. It was postulated that higher rates of irrigation may reduce aphid infestation by washing them off stems. Stem die-back did not show any pattern related either to irrigation treatment or any obvious environmental variables and was probably due to frost damage followed by secondary Fusarium infection of the weakened stems. In both 1999 and 2000, the occurrence of leaf-infesting pests and other leaf disorders was compared between the trials in the four countries and between the treatments of wastewater at different rates, no water and pure water and, in addition, urine and sludge treatment in N. Ireland and in Sweden.
Compared to 1999, leaf damages were more severe in all the aspects studied, except galled leaf margins in France. Damage by chrysomelid beetles was very severe in France as were abiotic stress symptoms in Greece. As in 1999, control trees were less stressed than those receiving wastewater treatments. Also mite frequency was lowest in the control treatment.
Objectives This project concerns an integrated investigation to provide an EU-wide (from northern to southern Europe) scientific basis for growing willow coppice for bioenergy production using municipal wastewater rich in, plant nutrient (substituting commercial fertilisers). A simultaneous environmentally acceptable, sanitary, and economically feasible disposal of the wastewater into the willow plantations, leading also to elimination of river, underground, and coastal water pollution. Two main objects for this study are the vegetation and the wastewater. Willow coppice is the vegetation which has to purify the water and produce bioenergy. The wastewater to be cleaned is a municipal wastewater or a wastewater from the food industry (with low content of heavy metals) which has been mechanically filtered and biologically treated in a secondary treatment step or further treated in open ponds before it is used in the plantations.
The specific objectives are:
Activities The work will be carried out in a period 50 months by six participants with significant experience obtained through many years of research on biomass production for energy uses and on wastewater treatment. The experimental fields will be established in four countries from both southern and northern European. In each country the experimental fields will be located in the vicinity of a municipal wastewater treatment plant or a food processing industry. The Swedish experimental field will be located at Romakloster, on isle of Gotland; in France at Orchies, in Northern Ireland close to the City of Londonderry and in central Greece at Larissa. On each experiment field up to 5 hectares of the SW-variety Joff (Salix viminalis) will be planted.
Studies of growth and biomass production will be made under five different treatments. These treatments include three different wastewater irrigation rates, pure water irrigation and one with humane urine (only on one site in Sweden). In each experiment field twelve/fifteen subplots (four/five treatments, three replicates) will be established with appropriate distance between the subplots, depending on local conditions, in order to avoid border effects. Samples of soil, soil water and biomass will be taken in the centre of each sub-plot. The effect of treatments on growth characteristics and variables related to biomass yield will be analysed and correlated with data from soil and groundwater analysis. An overall analysis of the four experimental fields will also be carried out so that a EU-wide evaluation of the wastewater irrigation system can be presented.
Progress The plantations were established in 1998 in Sweden, Northern Ireland and France, and in 1999 in Greece. The irrigation systems has been installed in France (1998) and during 1999 in the other three experimental sites. Initial soil samples have been taken and the wastewater analysis has started. Ground water pipes have been installed and the sampling of groundwater in the plantations will start during 1999. Earlier recorded climatic data has been gathered for each location to be used for calculation of the actual irrigation rates.
Results It is too early to start to analyse the results. Some biomass measurement have been made in the France trial, but this is just from the first year of growth. Current work is aimed at keeping the plantations free from weeds and to get a well established crop for the future studies. These studies of the economy, sanitary aspects, humane urine irrigation, clonal test, legal aspects and biological aspects of the willow/wastewater system have started.
Future activities Sampling of groundwater and analyses of groundwater and wastewater will start in full during 1999. A detailed protocol for the field trials has been produced and the techniques for sampling and biomass measurements are agreed. During 1999 a protocol for scoring of pest and diseases in the plantations will be produced and distributed. The sampling of groundwater will start now when the groundwater pipes are installed.
Discussion As the project was not finalised until late in the 1998 season, some actions related to the field trials had to be delayed and few actual results are available yet.
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Updated
by CPL Press:
03/07/2007
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