Influence of Post- and Pre-Acid Treatment during Hydrothermal Carbonization of Sewage Sludge on P-Transformation and the Characteristics of Hydrochar

Processes

Edward Antwi¹  Satyanarayana Narra¹  Vicky Shettigondahalli Ekanthalu¹  Tommy Ender¹  Michael Nelles¹ 

[1] Department of Waste and Resource Management, Faculty of Agricultural and Environmental Sciences, University of Rostock, D-18059 Rostock, Germany;

关键词: hydrothermal carbonization;    sewage sludge;    phosphorus;    phosphorous recovery;    hydrochar;    pH;   

DOI  :  10.3390/pr10010151

来源: DOAJ

【 摘 要 】

Phosphorus (P) recovery from alternative P-rich residues is essential to meet the growing demands of food production globally. Despite sewage sludge being a potential source for P, its direct application on agricultural land is controversial because of the obvious concerns related to heavy metals and organic pollutants. Further, most of the available P recovery and sludge management technologies are cost-intensive as they require mandatory dewatering of sewage sludge. In this regard, hydrothermal carbonization (HTC) has gained great attention as a promising process to effectively treat the wet sewage sludge without it having to be dewatered, and it simultaneously enables the recovery of P. This study was conducted to analyse and compare the influence of acid (H₂SO₄) addition during and after HTC of sewage sludge on P leaching and the characteristics of hydrochar. The obtained results suggested that despite using the same amount of H₂SO₄, P leaching from solid to liquid phase was significantly higher when acid was used after the HTC of sewage sludge in comparison with acid utilization during the HTC process. After HTC, the reduction in acid-buffering capacity of sewage sludge and increase in solubility of phosphate precipitating metal ions had a greater influence on the mobilization of P from solid to liquid phase. In contrast, utilization of H₂SO₄ in different process conditions did not have a great influence on proximate analysis results and calorific value of consequently produced hydrochar.

【 授权许可】

Unknown