Efficiency and factors for agricultural use of sludge in circular Bulgarian economy

Abstract

The issue of utilization of sludge from wastewater treatment in agriculture is an important socio-economic and environmental problem in the European Union and Bulgaria. Its significance is determined by the fact that the amount of sludge formed is constantly growing, as the annual amount of sludge produced in Europe is 8.7 million dry matter, and in Bulgaria reaches 53 thousand tons of dry matter. One of the main ways to utilize sludge from wastewater treatment in its use as fertilizer in agriculture. It is becoming topical issue along with the growing interests into effective "transformation of wastes into products" and their inclusion in supply chains and circular economy.In other countries, there are numerous studies on the effects, factors and efficiencies of sludge use in agriculture. Despite their relevance, in-depth studies of the diverse effects and critical factors of sludge utilization in Bulgarian agriculture are at an early stage. This paper presents results of the first part of a large-scale study aimed at determining the socio-economic effects of sludge utilization in Bulgarian agriculture. First, an approach is presented to assess the multilateral effects, efficiencies and factors of sludge utilization in agriculture. Then the various factors stimulating and limiting the utilization of sludge in Bulgarian farms are identified. The results of a case study of a holding using sludge as fertilizer are then presented.Based on a qualitative analysis of regulations and institutional structure, and surveys with managers and experts of urban wastewater treatment plants, and farmers using and notusing sludge, the institutional, political, organizational, personal, educational, informational, social, economic, and environmental factors influencing the utilization of sludge in agriculture in two regions of the country (Sofia and Burgas) are identified. Impact factors are generally divided into two types: factors influencing the behavior of agents, and factors determining the type and extent of the effects of sludge use in agriculture. Research of this type is to continue and deepen to establish the economic, sectoral and regional specificities on the basis of more representative information from all participants and interested parties in the effective utilization of sludge in the country.

Forming a System of Monitoring Business-Structures’ Activity in the Circular Economy Development

“…In addition, the authors found that during this period, the number of journals where the results of research on this topic were published increased from 39 to 1028 [40]. It should be recognized that due to the fact that the very concept of "a circular economy" is interdisciplinary, as well as the fact that the essence and goals of a circular economy development are considered at the global level, at macro-and mesolevels [41][42][43][44][45][46][47][48][49], the scientific research on the problems of forming the systems of monitoring in the context of a circular economy development at the micro level is practically absent. Despite this, there are studies of the circular economy of the systems of monitoring at the macro -and meso-levels.…”

Panoramic Semiquantitave Analysis for Multielement Characterization of Liquid and Solid Waste Samples

“…However, they are also a rich source of nitrogen, phosphorus, and organic matter, as well as essential trace elements [3,4]. Although various sludge treatment methods exist and are implemented, e.g., incineration, landfill [2,5], and recycling into building materials [1], an increasingly necessary application is its utilization in agriculture because of its high fertilization value [2,[5][6][7][8]. The chemical characterization of the sludge before its reuse is a key requirement in the principles of circular economy for development of appropriate technologies for processing and recycling of the waste material.…”

Socio-Economic, Technical and Environmental Indicators for Sustainable Sewage Sludge Management and LEAP Analysis of Emissions Reduction

“…The results showed that there are many issues related to the technological introduction of sludge in arable agricultural land and a lack of public acceptance of sludge utilization in agriculture. There are also other research papers focused on environmental [28,29], economic [29,30] and various other [31,32] indicators.…”