Recovering critical fertilisers such as phosphorus from sludge treatment

Acqua&Sole
Acqua&Sole
Organisation or Company
Acqua&Sole SRL
Type of organisation or company
Private company
Country
Italy
City
Vellezzo Bellini (PV) Lombardy Region
Language for original content
English,
Italian
Key Area
Production,
Waste management
Project elaborated in partnership
No
Sector
Agriculture, fertilisers and forestry,
Recover, Regenerative economy,
Waste management & Secondary Raw Materials
Scope
Regional,
Rural
Submitted by
ICESP (Italian Circular Economy Stakeholder Platform)
Start/End date
Ongoing
Yes
Type of funding
Private
Description

The Acqua&Sole company recovers organic matter and nutrients by regenerating resources from food industry waste.

Since 2016 their plant processes sludge and other organic waste from agri-food industry via thermophilic co-digestion. Anaerobic digestion and simultaneous extraction of ammonia produces at the end of the process:

  • digestate from waste
  • ammonium sulphate as a secondary raw material (REACH registered)
  • biogas.

Digestate fertilisation (as opposed to traditional chemical fertilisation) produces an organic substance, thus contributing to the improvement and preservation of soil structure, fertility, water retention and biodiversity.

Main activity field
Water supply; sewerage, waste management and remediation activities
Identified challenge (s)
Definitions of waste (regulatory uncertainty;)
Lack of enforcement
No circular regulation
Main results

Phosphorus is a critical material in agriculture fertilisation, but global stocks are finite and depleting. In 2020, the use of around 120 000 tons of digestate allowed for the recovery of:

  • 900 tons of phosphorus,
  • 90 tons of potassium and
  • 950 tons of nitrogen.

In 2020, around 4 000 tons of carbon were added to agricultural soils. The industrial-scale plant verified the economic sustainability of the initiative, which appears to be profitable.