Role of the composition of humic substances formed during thermal hydrolysis process on struvite precipitation in reject water from anaerobic digestion

Thermal hydrolysis process (THP) is a widely used pre-treatment method in the anaerobic digestion (AD) of waste municipal sewage sludge. A post AD dewatering step of the digestate produces a liquid stream called reject water. THP increases the concentration of humic substances (HSs) and nutrients in the produced reject water. Struvite...

Effects of thermal hydrolysis process-generated melanoidins on partial nitritation/anammox in full-scale installations treating waste activated sludge

Thermal hydrolysis process (THP) is a well-established anaerobic digestion (AD) pre-treatment technology. Despite the THP benefits the pre-treatment increases the concentrations of nutrients and melanoidins in the digestate reject water after dewatering. The increased concentrations of nutrients and melanoidins formed during THP-AD can impact...

Accumulating ammoniacal nitrogen instead of melanoidins determines the anaerobic digestibility of thermally hydrolyzed waste activated sludge

Full-scale thermal hydrolysis processes (THP) showed an increase in nutrients release and formation of melanoidins, which are considered to negatively impact methanogenesis during mesophilic anaerobic digestion (AD). In this research, fractionation of THP-sludge was performed to elucidate the distribution of nutrients and the formed...

Influence of humic substances created in THP on partial nitritation step of PN/A reactors

Anaerobic digestion (AD) is an effective and economical in secondary sludge management. Thermal hydrolysis process (THP) is a reliable pre-treatment method to improve the biodegradability of sludge. Partial nitritation and anammox process (PN/A) is a suitable method used to remove nitrogen in reject water which has a low COD/N ratio. However,...

Evaluation of a full-scale suspended sludge deammonification technology coupled with an hydrocyclone to treat thermal hydrolysis dewatering liquors

Suspended sludge deammonification technologies are frequently applied for sidestream ammonia removal from dewatering liquors resulting from a thermal hydrolysis anaerobic digestion (THP/AD) process. This study aimed at optimizing the operation, evaluate the performance and stability of a full-scale suspended sludge continuous stirred tank...

Effect of Melanoidins and Metals on Hydrolysis in Anaerobic Digestion

Sludge management has gained importance over the years due to high sludge treatment and disposal cost, stringent disposal laws, and a need to move towards sustainable energy production. Anaerobic Digestion (AD) of waste activated sludge (WAS) is a favoured sludge stabilisation technique due to its low energy footprint. Hydrolysis – the first...

Effects of thermal hydrolysis process (THP) on struvite crystallisation from reject water of anaerobically digested sludge

Various technologies have been implemented in wastewater treatment plants (WWTPs) to generate clean effluent with minimised impacts on the environment. Thermal hydrolysis process (THP) and struvite crystallisation reactors are two examples of these technologies. THP generates humic-like substances, known as melanoidins, that are presumed to...

Evaluation of compounds generated in the thermal hydrolysis process on microbial activities in partial nitritation/anammox process

Anaerobic digestion (AD) is a traditional technique to treat sewage sludge and produce biogas. Thermal hydrolysis process (THP) is a feasible pretreatment for AD by improving the biodegrdability of organic compounds. Partial nitritation/anammox (PN/A) process could be applied in side-stream for treating the reject water from AD since the reject...