Sludge and waste water application for energy plantation - case study from Lodz region in Poland

Within renewable energy sources available in Poland, biomass seems to have the largestpotential, estimated to 90%, About 70% of renewable energy should be obtained fromagricultural production of energy plants. Climatic conditions in Poland (vegetation period of210-215 days and precipitation of 500-700 mm) are profitable for willow plantation. Thenatural productivity can be as high as 14 Mg d,m. per ha, However, the productivity can beincreased by using waste water for irrigation and sludge for fertilisation,For decades an area of 4 500 ha of Ner River valley was used as a part of municipalwastewater treatment system for Lodz city, The valley has specific soil-water conditions withdeep sandy alluvial soils and shallow groundwater table. During the irrigation process theinflow of wastewater on an artificially formed border check infiltrates into the soil and fillsthe available porosity.Average outflow from wastewater treatment plant in Lodz (2 m3/s) and sludge dailyproduction of30 - 35 Mg d. m. (app, 170 Mg dewatering sludge) can be utilised on energybiomass plantation ( e.g. Salix Viminalis or grasslands) located in the Ner River valley