LAUSR

The chemical and physical properties of sludge collected from different aquatic areas differ from one another. Such differences have made the universal standardization of early settings difficult. Usage of artificial sludge with stable characteristics has been thus proposed in the present study. First, values of organic matter, sulfide content, and the inorganic content were measured for the sea sludge collected from Funabashi Port in Japan. Using the obtained chemical and physical properties as reference, we then produced artificial sludge by mixing dry yeast made from yeast cultured in liquid sodium sulfide nonahydrate solutions (3.5-4.0%) and zeolite for inorganic material. In the present study, we understood that we couldn’t obtain the desired organic content for the artificial sludge, simply by adding the yeast with the amount similar to the organic content percentage we aimed. We thus calibrated the amount of yeast by measuring the actual organic content of several artificial sludge samples by thermo-gravimetry analysis. We found out that we need only to write a calibration curve of three measurements (zeolite-dry yeast w/w% = 0%, mid-point, and 83.3%) in order to obtain the information about the right amount of dry yeast addition to produce an artificial sludge with desired percentage of organic material. Finally, we mixed 31.4% of dry yeast (zeolite and other inorganic materials = 68.6%), in order to obtain an artificial sludge with 23.6% organic content. This percentage is similar to the organic content of the sludge collected from Funabashi Port.