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

Lucian-Ionel Cioca,Geanina Maria David,Daiana Șeitoar,Alina-Oana Ciomoş,Roxana Maria Druță

doi:10.3390/recycling6030059

Lucian-Ionel Cioca, Geanina Maria David + Show 3 more

Open Access

https://doi.org/10.3390/recycling6030059

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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.

Highlights

The organic matter content of 50% indicates that the sludge is generally stabilized and the maximum value of 80% is valid for raw sludge
A maximum application rate of biosolids of 5t of dry substance/hectare is taken into account, based on the median concentration of nitrogen (3.6% N dry substance) and the maximum addition of 170 kg N/ha per year allowed in areas vulnerable to nitrates [22]
The analysis in this study investigated the economic effects of using biosolids in agriculture

Summary

Introduction

Industrial symbiosis is a subdiscipline of a more general scientific field, the industrial ecology. Should be transformed into a more integrated model: an industrial ecosystem. The industrial ecology started being developed in the late 1980s, with its first definition being agreed, by the scientific community, to be in the manuscript “Strategies for Manufacturing” from 1989, written by Frosch and Gallopoulos in Scientific American, where they state that “the traditional model of industry activity . In such a system, the consumption of energy and materials is optimized, waste generation is minimized, and the effluents of one process . In 1997, in the context of industrial ecology, Erkman proposed us to “understand how the industrial system works, how it is regulated and its interaction with the biosphere; on the basis of what we know about ecosystems, to determine how it could be restructured to make it compatible with the way natural ecosystems function” [2]

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