Industrial Symbiosis through the Use of Biosolids as Fertilizer in Romanian Agriculture

Abstract

Biosolids’ use in agriculture is an example of industrial symbiosis. The application of biosolids (BS) in agriculture is considered one of the most sustainable sewage sludge (SS) management options, but the quality of biosolids has to meet certain requirements regarding the characteristics of the sludge, those of the land and of the type of crop. Web of Science database has been used to search for the relevant literature. The review of studies undertaken in order to determine the economic effects of the use of biosolids in agriculture shows, in the majority, an increase in crop yield and the reduction in costs, due to the reduction in the requirements for the application of chemical or synthetic fertilizers. If the entire sewage sludge production in Romania for 2019 had been used as fertilizer, the estimated cost reduction for farmers would have been almost 3 million Euros—considering the 230.59 thousand tons of dry matter produced in 2019. The estimated savings for 2019 of the sewage and water utilities, if the sewage sludge had been used in agriculture instead of depositing it at the landfill, would have been about 3.9 million Euros. However, the limits of the symbiosis are due to the size of the farms, the type of plants cultivated, pH, slope inclination, heavy metal content and social acceptance. It is impossible to use all the sewage sludge in agriculture, but these figures are a good estimation of the economic effects.

A Systematic Review of the Effects of Fecal Sludge Derived Amendments on Crop Growth and Soil Health

“…Regarding sewage sludge biosolids, Ippolito et al 83 conducted a 22-year field study which found that biosolids improved soil chemical and biological health indices compared to inorganic fertilizers. Cioca et al 84 reviewed biosolids applications in Romania and found that they increased crop yields and reduced costs compared with SFs. A review by Lu et al 45 concurred that biosolids use in the USA produced "similar or higher yields than inorganic fertilizers, especially when applied for multiple years".…”

Integration as a Driver of Enterprise Sustainability: The Russian Experience

“…Industrial ecology includes some specialized tools and techniques that can be used within industrial symbiosis. The network of physical processes and relationships between companies that transform raw materials and energy into finished products and waste is known as the "industrial metabolism" [28][29][30]. The industrial metabolism, in addition to biological systems, is based on the use of by-products to form closed cyclic systems that produce minimal waste and consume fewer natural resources and energy.…”