Svea Birgit Ziegner

Ms. Svea Birgit Ziegner


Research Focus & Metrics

Academic Career Length

1Year (2026-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 April 2026 in Recycling
Verified
Journal Article
Open access
PDF file
DWDheeraja Winter
Dheeraja Winter
SZSvea Birgit Ziegner
Svea Birgit Ziegner
SKSimone Krafft
Simone Krafft
MGMarkus Grömping
Markus Grömping
Silvio BeierSilvio Beier
Silvio Beier
The paper sector is characterised by high freshwater consumption and a strong need for improved resource efficiency. In this context, industrial digestates derived from short-fibre residues in paper recycling mills represent a promising substrate for water recovery within a circular economy framework. This study investigated the dewatering of short-fibre digestates as a pre-treatment for downstream membrane processes, aiming to maximise the liquid fraction (LF) recovery while minimising dry matter (DM) content. Seven scenarios were studied: sedimentation (S0); pre-sedimentation with chemical addition using iron(III) chloride (FeCl3) + polydiallyldimethylammonium chloride (polyDADMAC) (S1), FeCl3 + starch (S2), Nanofloc® (S3), and polyDADMAC (S4); and direct dewatering without pre-sedimentation using polyDADMAC with cloth filtration (S5) and centrifugation (S6). With reference to the sedimentation supernatant, S4 achieved the highest DM separation efficiency of 76%, followed by S1 (64%), whereas S2 and S3 were below 40%. However, LF recovery relative to the initial digestate was limited in scenarios S1–S4 to 17% (170 g/kgdigestate), with DM concentrations of 2.0–4.8 g/kgLF. In contrast, direct dewatering increased LF recovery substantially, with centrifugation (S6) achieving up to 690 gLF/kgdigestate and cloth filtration (S5) 420 g/kgdigestate, while maintaining a low DM (1.7 g/kgLF). Chemical oxygen demand (COD) and phosphorus (Ptot) were largely separated from the liquid fractions in all the scenarios. Nitrogen (Ntot) and ammonium (NH4-N) in the LF remained more variable, ranging from 22 to 153 and 5 to 22 mg/kgdigestate, respectively. These results indicate that centrifugation with polyDADMAC is the most effective approach, suggesting that mechanical force with a chemical additive can be used for the efficient dewatering of short-fibre digestates.