Characterisation and comparative analysis of electrochemically and chemically generated sludge from chicken processing wastewater for sustainability management

This study presents a comprehensive characterisation of sludge generated from chicken processing industry wastewater (CPW) treated by two advanced methods: electrochemical treatment using iron (Fe) electrodes and chemical coagulation employing alum and polymeric flocculants (Rishfloc 8163, Telfloc 5630). Using a suite of analytical techniques - FTIR, SEM-EDX, TEM, Raman, NMR, XRD, TGA, ICP-OES and nutrient profiling - the chemical, structural, and reuse properties of the resulting sludges were elucidated. Electrochemical treatment produced a compact, iron-rich sludge with low ionic contamination, dominated by amorphous iron hydroxides formed via in situ electrode dissolution. In contrast, chemical coagulation resulted in a lighter, porous sludge containing alum residues and polymeric materials, reflected in higher salinity and conductivity. EDX confirmed dominant iron and oxygen in electrochemical sludge, while chemical sludge showed aluminum and silicon signatures. FTIR and Raman analyses indicated more advanced organic degradation in electrochemical sludge, with distinct iron oxide bands and reduced organic complexity. TEM revealed nanostructured iron particles in electrochemical sludge versus larger amorphous aggregates in chemical sludge. Nutrient analysis demonstrated agronomic potential in both, although chemical sludge contained higher nitrogen and phosphorus. Heavy metal content was within safe limits for reuse. This study underscores the advantages of electrochemical treatment in producing stable, nanostructured sludge suitable for sustainable agro-industrial applications, while recommending further risk assessment for long-term soil health impact.