A B S T R A C TIn this study, concentrated cellulose wastewater was re-utilized to synthesis water-retaining organic fertilizer by microwave-assisted polymerization which expanded the field of reapplication of cellulose wastewater. The content of the monomer, the microwave reaction power, the diatomite and the crosslinker were considered to investigate the influence of organic fertilizer absorbency on distilled water and seawater. The results showed that the water absorbency of the synthesized organic fertilizer was 117.67 and 82.32 g/g in distilled water and seawater, respectively. In addition, the contents of organic matter, nitrogen, phosphorus, Q2 potassium and heavy metals (Cr(III), Cd(II) and Hg(II)) in the obtained fertilizer samples were detected and the results revealed that all the contents complied with the standard for organic fertilizer in China.2015 Published by Elsevier Ltd. 6