Removal of Escherichia coli by Intermittent Operation of Saturated Sand Columns Supplemented with Hydrochar Derived from Sewage Sludge

Abstract

Featured Application: Bacterial removal in water treatment using a sand column supplemented with adsorbents derived from hydrothermally treated sewage sludge.Abstract: Hydrothermal carbonization (HTC) technology can convert various types of waste biomass into a carbon-rich product referred to as hydrochar. In order to verify the potential of hydrochar produced from stabilized sewage sludge to be an adsorbent for bacterial pathogen removal in water treatment, the Escherichia coli's removal efficiency was determined by using 10 cm sand columns loaded with 1.5% (w/w) hydrochar. Furthermore, the removal of E. coli based on intermittent operation in larger columns of 50 cm was measured for 30 days. Since the removal of E. coli was not sufficient when the sand columns were supplemented with raw hydrochar, an additional cold-alkali activation of the hydrochar using potassium hydroxide was applied. This enabled more than 90% of E. coli removal in both the 10 cm and 50 cm column experiments. The enhancement of the E. coli removal efficiency could be attributed to the more hydrophobic surface of the KOH pre-treated hydrochar. The idle time during the intermittent flushing experiments in the sand-only columns without the hydrochar supplement had a significant effect on the E. coli removal (p < 0.05), resulting in a removal efficiency of 55.2%. This research suggested the possible utilization of hydrochar produced from sewage sludge as an adsorbent in water treatment for the removal of bacterial contaminants.

Granular Activated Carbon from Grape Seeds Hydrothermal Char

“…Larger pore size (meso-pores) activated carbon, suitable for wastewater treatment applications, was prepared form hard biomass (coconut shells and date stones) hydrochar by using NaOH as activating agent [28,29]. Raw hydrochar and hydrochar activated with KOH was prepared and used for water treatment by Chung et al [30], starting from sewage sludge. Recently, Rodriguez Correa et al [31] produced hydrochar from the digestate of a biogas plant and activated it with KOH.…”

Special Issue on Wastewater Treatment and Reuse Technologies

“…Recently, hydrothermal carbonization has been suggested as a cost-effective and eco-friendly solution for this sewage sludge management challenge. In their article, "Removal of Escherichia coli by Intermittent Operation of Saturated Sand Columns Supplemented with Hydrochar Derived from Sewage Sludge", Chung et al [8] evaluated hydrochar derived from sewage sludge as an additive adsorbent in sand filtration setups for Escherichia coli removal during water treatment. Supplementation of activated hydrochar in a sand filtration unit significantly improved E. coli removal efficiency.…”

“…Supplementation of activated hydrochar in a sand filtration unit significantly improved E. coli removal efficiency. Given that pathogen removal based on the use of hydrochar is a new concept, Chung et al [8] recommended follow up investigations on the optimization of the process parameters and the durability of the filtration unit for practical implementation in developing countries.…”

Purification Treatment on Polluted River via Combinations of Gravel Contact Oxidation Treatment and Surface Flow Constructed Wetlands-A Case Study in Changhua County, Taiwan

“…As the result, the discharged household wastewater dramatically polluted the quality of river. There were many purification technologies, including membrane filtration, wet pyrolysis, coagulation process, and anaerobic digestion [6][7][8][9], used on waste and wastewater treatment. Besides, the EPA started to announce many policies and strategies regarding wastewater pollution treatment to local government since 2002.…”