Sewage Sludge Quality and Management for Circular Economy Opportunities in Lombardy

Abstract

From the perspective of a circular economy that prioritizes resource reuse and recovery, sewage sludge could be a source of nutrients for agricultural soils or a source of energy, depending on its characteristics. Lombardy is the region with the highest quantity of sludge production and management in Italy. A methodology was developed to: extract and analyze quantitative data on sewage sludge (EWC 190805) production and management (2017–2018); collect and analyze qualitative data from publicly available documents in tender processes for sewage sludge management (2014–2020). Sludge from Lombardy’s wastewater treatment facilities displayed average qualities that were useful for recovery in agriculture after additional stabilization treatments. Sludge showed generally low heating values and elevated water content and should require additional treatments to be used in mono-combustion. The study discovered that there is still work to be done in sludge recovery in agriculture in Lombardy, taking biosolid quality into account. Sludge, on the other hand, can be converted into energy. The methodology for collecting and analyzing site-specific data presented here can be applied to other areas. The findings can assist and guide decision-makers in developing future regional sewage sludge management strategies.

Advances in sewage sludge application and treatment: Process integration of plasma pyrolysis and anaerobic digestion with the resource recovery

“…According to Durdević et al (2019) [ 57 ] publication, at the end of 2016, Croatia produced about 21,366 tons of sludge in dry basis and this amount is expected to increase up to 10 5 tones by the year of 2024. In Ireland, Hungary, Spain, Cyprus and Finland, the mostly adopted SS treatment methods are composting and incineration, they are also highly used in Germany, Netherlands, Austria and Belgium [ 58 ]. Those treatment techniques are chosen for SS management as influenced by the scarcity of land for agriculture and population size.…”

To spread or not to spread? Assessing the suitability of sewage sludge and other biogenic wastes for agriculture reuse

“…Present regulations on the recovery of sludge in agriculture, worldwide, focus on a few chemical and microbiological indicators on sludge and soil, with some use limitations. An updated review on sewage sludge characteristics in Italy is reported in Domini et al [ 10 ]. The debate on the suitability of these regulations is still open and controversial.…”

Behavior of PCDD/Fs and PCBs from Wastewater Treatment Plants during Sewage Sludge Composting: Study of Semi-Anaerobic Conditions and Different Stages of the Process

“…Nevertheless, sewage sludge treatment activities focus on improving its quality for recovery opportunities (which should include organic pollutants control) while minimizing the quantities to be treated and disposed in accordance with the EU Directive on waste [7] and the Circular Economy Action Plan [8]. In this sense, the current plan calls for wastewater treatment plants (WWTPs) to be turned into water resource recovery facilities (WRRFs) [9].…”