WP3

Land spreading; Knowledge and Practices of Using Treated Sewage Sludge for Plant Cultivation, soil remediation and Soil Carbon Sequestration; The research activities of WP3 will focus on the use of “bio-soils”, i.e. soil products with treated sludge as  a central ingredient firstly on areas where “energetic” plants are produced. This type of land use is increasing in many countries and may represent a very interesting alternative to use on farmland in the future. Secondly, it can be used in degraded land restoration. The simultaneous use of green plants as a remediation tool in environmental cleanup can take up and bioaccumulate (phytoextraction) as well as immobilize (phytoimmobilization, phytostabilizatiom) certain trace elements, in conjunction with their rhizospheric processes. Also soil organic carbon sequestration will be provided.


 Highlights


  • Single application of sewage sludge resulted in dense plant cover
  • Lead(Pb) made strong complexes with soil C, and thus avoiding its translocaction into aboveground biomass
  • In the absence of fertilization, trees accumulate metals primarily in needles 

Executive summaries of WP3 results


During the project period, all the planned milestones were already achieved in the planned period. In order to carry out the tasks provided in the project, numerous laboratory tests, growth chamber and field studies were conducted. In the laboratory, physical and chemical parameters of soil, compost, organic additives and biomass were examined. In addition, carbon sequestration in soils was also investigated. During the CUT- NMBU collaboration, the DGT technology was applied to estimate the bioavailable fraction of metals in soils in a pot experiment. The metal speciation was conducted of pore water withdrawn using WHAM/Model VII. To achieve M3.1.1, the activities performed were analysis of chemical composition of different composts for their use in remediation process and the research on the use of selected compost for improved phytoremediation. The use of Scots pine and organic additives contributed to improving the physical and chemical properties of the soils. Chemical composition of obtained biomass indicates that for plants growing on lignite mine dumping site soil, a significant increase of trace elements was noted when selected compost was applied. To achieve the M3.1.2. milestone, the activities performed were the study of literature, surveys, discussions and meetings with the owners of degraded land and with investors, users of such areas, and the inhabitants directly connected to such areas. To achieve M3.2.1., a pot experiments in the growth chamber and the field experiments were conducted. Different experiments were conducted to determine the impact of compost’s initial conditions on the growth of energy plants grown on degraded and contaminated soils and on remediation of contaminants. Hence, composts, vermicomposts and other organic amendments were made use of. The composts were obtained from materials from WP1 (anaerobic digestion). Later the digestate obtained was used for composting/vermicomposting process (WP2). The numerous composts obtained through this process were tested in pots studies using rape (Brassica napus L. var. napus) and fescue grass (Festuca rubra) as test plants. The two selected compost were applied in pot studies grown with miscanthus (Miscanthus giganteus ), and another of the selected composts was applied in field studies. A field study was conducted using selected (from the pot experiment) amendments i.e. compost, sewage sludge, lacustrine chalk (all containing carbon). Pine (Pinus sylvestris L.) and Miscanthus (energy crop) were grown in soils close to the zinc smelter in Miastechko Śląskie and in a post-mining land lignite mine dump in Belchatow. This experiment was conducted applying two doses of organic amendments. To achieve the milestone M3.3.1. and investigate the use of organic amendments for improved phytoremediation and soil organic carbon phytosequestration process, growth chamber and field studies were conducted. A series of indicators including CMI and SOC pools were determined. The purpose of their application was the estimation of carbon sink and carbon storage in the two degraded soil types. Soil fertility and soil quality was improved, based on changes in TN, TC and TOC contents in the soil. The degree of leaching and loss of soluble organic matter from the soils were determined by measurements of DOC concentrations in the soil solution. Within the WP 3 activities, two workshops took place, (i)workshop on „Sewage sludge as a nutrients source” (in Czestochowa) and workshop on „Knowledge and practices using treated “SS”with special skills-international training course at NMBU Aas (3.2.1.2 International Training Course, Norway). In addition, the monthly internship program for two PhD students was performed at NMBU Aas ( Norway). The results and progress of the project were presented at international conferences and disseminated on the website of the project. The summary of the achieved results was presented and discussed during the Concluding Conference (Cracow). As for M3.3.2, future research topics were discussed and defined. It was found that carbon sequestration is an important part of an overall carbon management strategy to help reduce and/or mitigate global CO2 emissions. Future research are needed to unravel how enhance SOC sequestration in terrestrial ecosystems. Such practices could help “buying time” for other methods of sequestration and energy technologies to come up on-line. Technologies facilitating terrestrial carbon sequestration is of utmost importance to develop further for mitigating the increasing atmospheric release of C. Achievements Taks 3.1: The achievement resulted in the following conclusions, that the revitalization of industrial and mining areas, if only because of the large surface area, is often a matter of great importance for planning of sustainable development at local and regional levels. From early stage on, successful revitalization requires cooperation by all stakeholders, along with integrated development, evaluation and elaboration of reuse vision. To enable such areas for sustainable land management policies and to succeed in effective and sustainable regeneration of the area, which will be compatible with the needs of stakeholders and takes into account the problems typical of such areas. It is inevitable to implement appropriate procedures for planning, assessment and support technologies offering in managing the economic and ecological risks. To achieve a successful revitalization of even smaller projects with lower complexity of remediation, it is essential to strategically integrate analysis of planning, legal, cultural and economic aspects. The standard revitalization approach will not produce appropriate results for the remediation of large areas, as is the case for opencast mining of lignite, or degradation as a result of metalliferous dust emissions from steel mills. Therefore, the type and extent of the required procedures for the remediation and redevelopment costs must be included in the expected benefits of the intended use of the land. In addition, we should find a solution that will be agreed upon and will be supported by stockholders and lobbyists for many years. Task 3.2: it was found that the effect of biosolids on the promotion of plant growth and biomass increment in shoot and roots was significant. Moreover, most of the applied organic substances improved the condition of degraded soils. The growth improvement and visible quality enhancement of aboveground biomass was recorded in rape and miscanthus after the application of organic substances to degraded soils. The release of nutrients (especially N) from sewage sludge into the soil occurred over a short period, which may pose a potential threat of contamination of surface and ground waters. Miscanthus may be used for the remediation of humus less soils and degraded areas due to its excellent adaptation properties and ability to survive in difficult environment. Compost was the most successful organic waste product in terms of growth and development promotion for both rape and giant miscanthus. Provided that organic substances was added in sufficient amount, cultivation of crops with adequate growth of biomass was possible in both of the degraded soil types. The application of sewage sludge and compost to degraded soils also limits the mobility of heavy metals and prevents from their leaching to ground waters. Lacustrine chalk was the most successful organic waste product in terms of growth and development promotion for pine and Miscanthus. The cultivation period of energy crops was too short to show the actual increment of biomass satisfactorily. The cultivation of crops and their development of biomass is possible in both of the degraded soil types, provided that organic substances are added over a long period. We found that the chosen organic soil additives, enable the development of plants on degraded lands and the establishment of vegetation cover, thus reducing water and wind erosion. Thus, these plants can be used in the remediation of soil and of devastated areas, as pioneering plants. Moreover, as a biosolid, the treated sewage sludge should be used in the form of compost to achieve significant efficiency of carbon phytosequestration. Conducted research on degraded areas, deprived of humus layer and vegetation, allowed to explore the relationship between the application of organic substances and selected plant species on improving the quality of soil. Task 3.3; It was found that selected soil amendments and plants species improve the soil organic carbon sequestration (SOC) and for safe and beneficial usage of sewage the compost formula is recommended. During the experiments, a series of indicators, including CMI, SOC pool, C stock, C sequestration rate, SOC build up rate, were used. In the pot experiment, the introduction of additive fertilizers did not cause a significant increase of carbon contents in soils, poor in this element, and therefore DOC leaching was limited. Only application of lacustrine chalk, to zinc smelter soil, contributed the increased concentration of POC and DOC in soil solution. Whereas, the high concentration of POC and DOC in brown coal mine soil could be associated with a high clay fraction in this type of soil. Low carbon input values and low concentration of carbon in soils at the beginning of the experiment, were resulted in a low storage capacity of this element. At the same time, the higher values of this indicators in zinc smelter soil than in soil collected from coal mine land were noted. This result may be explained by the fact, that the soil from smelter area has a higher content of different types of carbon. In most cases, the introduction both plant species contributed to a slight increase in CMI, SOC pool, C stock, C sequestration rate, SOC build up rate. Cultivation of pine can reduce mineralization of organic matter and carbon leaching into the soil profile. Chemical composition of SOC is central to soil fertility. The effect of soil amendments and duration of their application on SOC composition was examined by 13C nuclear magnetic resonance (NMR) spectroscopy. The SOC content in the fertilization treatments were even 50% higher than in control treatments. This indicates significant differences in SOC content with time of fertilizer application between the treatment groups. There was a significantly greater proportion of O-alkyl C and a lower proportion of aromatic C in the organic fertilization than in control. Additionally, execution of principal component analysis showed that the C functional groups from various fertilization strategies tended to become compositionally similar with time. The results suggest that a shift in SOC chemical composition may be firstly dominated by fertilization strategies, followed by fertilization duration. Funding has been used for laboratory (growth chamber) and field tests (two localizations: lignite mine dumping site, central Poland and area surrounding zinc smelter, (Silesia) carried out in Polish-Norwegian cooperation, analysis of samples, purchase of purchase of laboratory consumables, organization of training courses, internship , workshop and participation in conferences.