Anaerobic co-digestion (AcoD) of grease trap waste (GTW) and sewage sludge (SS) is an attractive management option for GTW valorisation and the transition to energy-neutral wastewater treatment plants (WWTPs). The main constraints that limit the direct use of GTW as a co-substrate in WWTP anaerobic digesters are the high content of non-disabled materials (floating plastics and fibres) and the low anaerobic biodegradability rates. This study assessed a single-step alkali and sieving pre-treatment of GTW at a low temperature (<25 °C) to improve the bioavailability of GTW and facilitate its use as a co-substrate. The experimental results showed that the alkaline pre-treatment of GTW at NaOH doses of 20–30 g_NaOH·kg_VS⁻¹ allowed the recovery of approximately 55–62 % of organic matter (on a volatile solids basis) present in the GTW in the form of saponified fat and generated a small waste reject fraction. Full-scale anaerobic AcoD assays (SS and pre-treated GTW) did not show inhibitory or operational problems under the experimental conditions and tested concentrations. Finally, a preliminary economic assessment for a 160 000 population equivalent WWTP in a European scenario presented a payback period of 1.75 y.

油脂捕集器废物（GTW）和污水污泥（SS）的厌氧共消化（AcoD）是GTW增值和向能源中性废水处理厂（WWTP）过渡的有吸引力的管理选择。限制在污水处理厂厌氧消化池中直接使用GTW作为共底物的主要限制因素是非残废材料（漂浮的塑料和纤维）的含量高以及厌氧生物降解率低。这项研究评估了GTW在低温（<25°C）下的一步碱式和筛分预处理，以提高GTW的生物利用度并促进其作为共底物的用途。实验结果表明，在20–30 g _NaOH ·kg _VS ^-1的NaOH剂量下，对GTW进行碱性预处理允许以皂化脂肪的形式回收GTW中约55-62％的有机物（以挥发性固体为基础），并产生少量废物。全面厌氧AcoD分析（SS和预处理的GTW）在实验条件和测试浓度下未显示抑制性或操作性问题。最后，在欧洲情景中对16万人口当量污水处理厂的初步经济评估显示，投资回收期为1.75年。