The impact of the council direcitve 86/278/EECon the treatment and usage of sewage sludge in Latvia

Abstract

The article provides the results of the project - assessment of sludge treatment technologies used in world's practice and detection of the most optimal option as solution for waste water sludge treatment in Latvia taking in account generated sludge quantities, humidity, pollution type and their concentration. There were investigated sludge properties and detected the price of such treatment methods as sludge prolonged storage, composting, mesophilic anaerobic treatment and usage for energy plants growing. It was stated that composting is comparatively cheap and safe method, limiting hazardous pathogens if it is realized as open windrows during summer. To improve existing situation of sewage sludge treatment and use which is similar in all Baltic republics, and taking into account the climate conditions in Baltic, were elaborated recommendations for accomplishing the proposal of new EC Directive. It was recommended to include the biological tests and their results as obligatory requirement in the certification of sludge as fertilizer and accept as obligatory action sludge hygienic treatment before its usage for growing food products and selling for manual spreading. On the bases of the real situation in Latvia - to remove the sludge long-term storage method from the list of recommended treatment methods and introduce new recommendations for sludge usage as fertilizer in energy plant growing.