Improving Dewaterability and Other Properties of Citric Acid Wastewater Treatment Sludge by Ozone and Peroxone

ABSTRACT

The efficacies of ozonation and peroxone (O₃/H₂O₂) pretreatments were compared for citric acid wastewater sludge conditioning with the objective of improving dewatering characteristics of the sludge. Treatment with 84 mg O₃/g dry solid (DS) and 12.5 mg/g DS H₂O₂ greatly enhanced the effectiveness of ozonation, providing sludge dewaterability similar to that obtained by ozonation at 250 mg O₃/g DS. Most importantly, treatment of citric acid wastewater sludge with 84 mg O₃/g DS and 12.5 mg/g DS H₂O₂ led to the preservation of the nutrient elements nitrogen, phosphorus, and potassium in the sludge with a minimal volatile suspended solids/total suspended solids reduction of 5.5%, which is much lower than that with ozonation at 250 mg O₃/g DS.

KEYWORDS:

• Ozone
• peroxone
• citric acid wastewater sludge
• extracellular polymeric substances
• dewaterability
• nutrient elements

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Additional information

Funding

This work was financially supported by the General Project of Beijing Educational Committee (KM201810011011), National Water Pollution Control and Management Projects (2017ZX07301-004), the Open Research Fund of Key Laboratory of Cleaner Production and Comprehensive Utilization of Resources, China National Light Industry, Beijing Technology and Business University, and National Natural Science Foundation (51608011).