Use of sewage sludge and zeolite for fertilising fields in Nea Orestiada by the Democritus University of Thrace
Use of sewage sludge and zeolite for fertilising fields in Nea Orestiada by the Democritus University of Thrace
The initial findings in the field were positive and offer the potential for better utilisation of urban wastewater
The use of sludge from the Orestiada Municipality’s biological treatment plant, which was trialled by the School of Agricultural and Forestry Sciences at the Democritus Universityin Orestiada.
The University has been using the sludge on a trial basis on crops of soft wheat, maize and sunflower crops, and has recently agreed with the municipality to utilise sewage sludge from the Orestiada Municipal Water Supply and Sewerage Authority (DEYA) facilities.
The local council is funding the research, which will run for two growing seasons, with 55,000 euros. It is high time that our country adapted to waste management and the utilisation of waste for the production of new products. This process is now an established practice in all European Union countries, whilst in our country it remains on paper or at the research stage. Practices of this kind represent a significant step forward for the environment, as well as for local production and the economy.
Advantages
Sewage sludge is a reusable material produced by urban wastewater treatment plants. One application of this is in agriculture, according to the Dean of the School, Spyros Koutroumpas. ‘The average organic matter content of Greek soils is 1 per cent and is declining, as it oxidises due to prevailing climatic conditions. In contrast, the average organic matter content of Greek sludge is 45 per cent. When we add organic matter to the soil, we improve key functions such as soil structure, porosity, and the capacity to retain water and nutrients. In other words, we improve its fertility.’ Furthermore, the nutrients in sewage sludge are utilised. The average composition of Greek sewage sludge is up to 4.4 per cent nitrogen, 4 per cent phosphorus and 0.3 per cent potassium, meaning it has a high nutrient potential. Its application helps to combat soil erosion and desertification in agricultural land.
Mr Koutroumpas notes that they have begun using it on field crops, explaining that their focus is on the crops grown in the region. In the first stage, the university will carry out the research on small experimental plots, on farmers’ fields where they will be able to see the results for themselves. ‘If the sludge is utilised, we expect to cover an area of 800–1,000 stremmata at most.’
Study
“Under the contract, the basic characteristics of the sludge will be studied. We will assess it against the criteria set out in European Union directives and Greek legislation regarding its suitability for agricultural use. We will also examine the impact of its application on key soil fertility indicators, as well as the potential increase in heavy metals,” he explains, adding that they will also incorporate zeolite, which can absorb any heavy metals. Through the research, they aim to compare crop yields with inorganic and organic fertilisers. Finally, they will examine the cost of the project to determine whether it will bring financial benefits to the farmer. “The results of the experiments are excellent. The farmers who have seen them in the field are delighted,” he reports. The contract with the local council includes the dissemination of the results to the farming community.
source: Ypaithros.gr