Typical used disposable nappies usually consist of nonwoven fabrics, Super Absorbent Polymer (SAP), and organic material, namely fluffy pulp, urine and/or excreta. Currently, this waste stream is being disposed to landfills causing many environmental issues. An alternative management method could be the valorisation of the biodegradable material through anaerobic digestion, and the recycling of plastics and SAP. Pretreatment of nappies is mandatory to separate SAP and plastics from the organic material. The aim of this work was the development of a process to minimize SAP’s volume, as this component can swell up to 1500 times its own mass by water absorbance, thus hindering any further biological process. CaCl₂, MgCl₂, and a range of CaCl₂/MgCl₂ combinations were tested against their deswelling efficiency on SAP, residual reagent concentration and reagent cost. The mixture of 20% CaCl₂ and 50% MgCl₂ (w/w) of SAP was concluded as the suitable combination of salts achieving a final SAP volume reduction of 92.7% with low residual cation concentrations and minimum cost. The physicochemical characterization of nappies’ hydrolysate that took place to estimate its adequacy as substrate for anaerobic digestion resulted to a COD:N ratio within the acceptable range for a subsequent anaerobic digestion processing.

典型的用过的一次性尿布通常由非织造织物，高吸收性聚合物（SAP）和有机材料（即蓬松的果肉，尿液和/或排泄物）组成。当前，该废物流正被丢弃到垃圾填埋场，引起许多环境问题。一种替代的管理方法可以是通过厌氧消化对可生物降解材料进行估价，以及塑料和SAP的回收利用。尿布的预处理对于将SAP和塑料与有机材料分开是必须的。这项工作的目的是开发一种方法来最大程度地减少SAP的体积，因为该组分的吸水率会膨胀至其自身质量的1500倍，从而阻碍了任何进一步的生物学过程。CaCl ₂，MgCl ₂以及一系列的CaCl ₂ / MgCl ₂测试了这些组合的相对于SAP的溶胀效率，残留试剂浓度和试剂成本。结论是SAP的20％CaCl ₂和50％MgCl ₂（w / w）的混合物是盐的合适组合，最终SAP的体积减少了92.7％，残留阳离子浓度低且成本最低。尿布水解产物的理化特性用来估计其作为厌氧消化底物的适当性，导致COD：N比在随后的厌氧消化过程可接受的范围内。