Flocculation of Real Sewage Sludge Using Poly-γ-glutamic Acid Produced by <i>Bacillus</i> sp. Isolated from Soil

To promote the use of sewage sludge on farmland, a flocculant compatible with agricultural application is required. In general, an inorganic flocculant such as aluminium sulfate is used at large sewage disposal plants. However, there is concern that aluminium accumulates when it is returned to farmland, and therefore a biodegradable rather than an inorganic flocculant is required. To obtain biodegradable flocculants produced by microorganisms,...