Technological and management aspects of the anaerobic co-digestion of sewage sludge with vegetable and organic wastes

Abstract

Sewage treatment plants (STPs) sanitize wastewater so that it

can be discharged into natural watercourses. As a result of this

treatment, biosolids or sludge are generated. Sludge disposal is a

potential source of soil and water pollution, and its management

can account for up to 50% of the operational costs of wastewater

treatment facilities. On the other hand, the management of other

sources of organic wastes such as fruit and vegetable waste (FVW)

represent a challenge and an opportunity, due to their high volumes

and potential energy valorization though biological and thermal

processes.

In this article, we review the main reports regarding anaerobic

co-digestion of sewage sludge with FVW and similar residues. Only

pilot and full-scale experiences were included in our search, in an

attempt to provide a realistic assessment of the degree of technology

adoption in industrial plants. Additionally, we review the current

Chilean, European and American regulations regarding final disposal

or elimination of sludge, with emphasis on those that involve waste

energy valorization, such as incineration in cement plants.