Good practices and experiences in sludge management and treatment

About

A workshop on good practices for sludge management and treatment was held in Warsaw on 6-7 June 2018.

Target audience

The workshop was targeted to representatives from managing authorities, line ministries and beneficiaries that are responsible for the development and oversight of projects in the water sector.

Objectives

Approximately 10 million tonnes (dry solids) of sewage sludge are generated annually in the EU. The costs of treating, utilising and disposing of this sludge can be substantial – accounting for up to 50% of the costs of waste water treatment in extreme cases.

The management options for sludge are constrained by legislation, such as the Landfill Directive (1999/31/EC) and the Sewage Sludge Directive (86/278/EEC).

However, sludge is also viewed as a resource, not only in agriculture as a soil conditioner and fertiliser, but also as a source of renewable energy and of phosphorus, for which a range of recovery technologies are emerging.

This interactive workshop aimed at providing information on the options available for sludge management, the advantages, disadvantages, practicalities and costs of existing and emerging techniques, as well as information on sludge management approaches being used throughout Europe.

Detailed case studies were presented from a range of EU Member States, namely Poland, Croatia, Sweden and Denmark.

During the second day, participants had the opportunity to visit Czajka Wastewater Treatment Plant (WWTP), the main WWTP serving Warsaw, and the largest and most modern wastewater treatment plant in Poland. The plant is designed for a population of 2.1 million people and a daily inflow of 435,000m³.

Sludge in Czajka WWTP is treated by gravity and mechanical thickeners prior to digestion and de-watering. The residual sludge is incinerated and the ashes are transported to landfill.