Research of Effective Microorganisms on Dairy Sewage Sludge Stabilization

The present paper was aimed at determining the influence of particular methods and biological processes, including the application of Effective Microorganisms, on the change in characteristics of the treated dairy sewage sludge, especially when discussing the changes in the content of nutrients and macroelements. The purpose of the conducted research was to specify the possibility of using natural biological methods of dairy sewage sludge treatment and adapting it to environmental, especially farming use. Diagnostic research on the content of sewage sludge from dairy wastewater treatment plants in the north-eastern region of Poland has been conducted since the 1990s. On the basis of the results and the assessment of the possibility of agricultural utilization of dairy sewage sludge, the objectives for research on sludge treatment were established. The research facilities were located on the premises of Municipal Wastewater Treatment Plant in Zambrów. The choice of location for the research facilities was guided by the possibility of supplying the same sludge from dairy wastewater treatment. The excess sludge from biological dairy sewage treatment, which was aerobically stabilized in separate chambers, was used in the research. In all of the facilities where sludge was treated with biological methods, Effective Microorganisms (EM) were also used for comparison. In the years 2010-2013, the research was conducted in the research facilities (own project) constructed and launched in 2010, which were planted with phragmites and common osier. In the years 2010-2012, the research was conducted in the research facilities (own project) constructed and launched in 2010, i.e. vermiculture patches. The conducted research was comprehensive and the obtained experiment results point to the necessity of continuation and further development of research concerning the content transformation in dairy sewage sludge during its biological treatment. Establishing the role of microorganisms present in the EM formula on the processes and transformations occurring in biologically treated sewage seems to be of exceptional importance. The innovativeness of the research lay mainly in a very comprehensive range of natural biological methods of treatment applied for the same sewage sludge coming from dairy wastewater treatment plants. The conducted research points to the influence of the EM formula on vital changes in the content of macroelements in the biologically treated dairy sewage sludge. The most important impact (from the point of view of the number of parameters and the change in size as a result of applying EM formula) was observed in reference to the vermicomposting process with the use of earthworms and long-term stabilization in reed beds. The statistical assessment methods applied to the obtained results of own research (Wilcoxon and Spearman tests, Spearman’s rank correlation coefficient) point to a significant influence of the EM formula on different “behavior” of many analyzed characteristics of the treated sludge.