Deliverable D. 2.6 ("Sludge minimization by different techniques") of ROUTES project

The ROUTES project is addressed to study new innovative solutions based on different approaches for minimizing sludge production in wastewater treatment. This report shows the results obtained by applying two different solutions proposed by IRSA, i.e. the Sequential Batch Biofilter Granular Reactor (SBBGR) based technology and Membrane Bio Reactors (MBR) with integrated sidestream process on the sludge recycle. After the preface, Chapter 1 is addressed to SBBGR technology. In particular, an introduction to SBBGR technology, the description of the experimental set-up used and operating programme are reported. The second part of chapter is devoted to the discussion of the results obtained during the experimental campaign with the lab-scale plant operation, and to the evaluation of the effectiveness of the SBBGR on minimization of sludge production and organic load removal. Chapter 2 is dedicated to the solution including a membrane bioreactor (MBR) integrated with a side-stream reactor. An introduction about the different mechanisms for sludge reduction in biological processes is followed by a literature review about the potentials and drawbacks of ozonation, sonication and anaerobic reactors in light of their application with MBRs. Then, the report describes the experimental investigation on the adoption of an anaerobic side-stream reactor, and the results of different tests on two lab-scale systems are reported. These include the assessment of key operational parameters and the identification of optimal operational conditions for both the MBR and the anaerobic side-stream reactor.