Biofertilizer from wood waste and sewage sludge with a high nitrogen content

Abstract

In Russia, the issue of wood waste processing is acute. One of the ways to reuse sawdust is to process them into
 biofertilizers, but due to the low nitrogen content in the composition, additional components must be added. In this
 regard, the possibility of enriching sawdust with sewage sludge, which is waste from sewage treatment plants, has been
 considered. In the work, the composition of the nutrient medium was optimized by the method of a full factorial
 experiment to increase the efficiency of the production of biosuppression enzymes, the biodegradation capability of
 microorganisms was evaluated. The biosynthesis of the consortium on the selected medium significantly increased the
 enzymatic activity: proteolytic activity increased 3 times, lipolytic - by 32.8%, amylolytic – by 69.2%. Optimization of
 the growing conditions of the consortium allowed reducing the level of wastewater pollution by 84.1%. The sediment
 formed during purification, due to the modification of activated sludge by the biocomposition of selected
 microorganisms, was a product of high biological value: the amount of organic matter increased by 25.7%, total
 nitrogen increased by 1.7 times, and carbon – by 5.2%. The enrichment of sawdust with sewage sludge makes it
 possible to use the mixture as a fertilizer with high nutritional value for plant growth and development. The introduction
 of biocomposite into the soil allows to increase its fertility and improve the structure.