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Hydrothermal carbonization (HTC) is an attractive, green technology for the management of sewage sludge. In this study, low-value secondary sewage sludge was subjected to an HTC treatment in a 1 L batch hydrothermal reactor and transformed into a high-energy-density hydrochar under varying HTC conditions (temperature of 150–300 °C, carbonization time of 30–150 min and a solid loading of 10–30%). The resulting hydrochar fuel characteristics were analyzed for ultimate and proximate analyses, functional group composition and energetic parameters. It was found that the hydrochar yield decreased with the increasing HTC temperature and reaction time, primarily due to the loss of organic volatile matter and functional groups. Under the optimum conditions of 150 °C, 30 min of carbonization time and 30% solid loading, 80.56% of the hydrochar was recovered, providing a maximum energy yield of 90.32% and a high heating value of 18.49 MJ/kg. Compared to the raw sewage sludge (H/C ratio of 2.67 and O/C ratio of 0.51), the hydrochar also had lower H/C and O/C atomic ratios of 1.42 and 0.18, respectively. The results suggest that significant dehydration and decarboxylation during the HTC treatment of sewage sludge have resulted in the formation of carbonaceous hydrochar with energetic properties close to the sub-bituminous coals. [ABSTRACT FROM AUTHOR]

Wastewater monitoring for SARS-CoV-2 has attracted considerable attention worldwide to complement the existing clinical-based surveillance system. In this study, we report our first successful attempt to prove the circulation of SARS-CoV-2 genes in Malaysian urban wastewater. A total of 18 wastewater samples were obtained from a regional sewage treatment plant that received municipal sewage between February 2021 and May 2021. Using the quantitative PCR assay targeting the E and RdRp genes of SARS-CoV-2, we confirmed that both genes were detected in the raw sewage, while no viral RNA was found in the treated sewage. We were also able to show that the trend of COVID-19 cases in Kuala Lumpur and Selangor was related to the changes in SARS-CoV-2 RNA levels in the wastewater samples. Overall, our study highlights that monitoring wastewater for SARS-CoV-2 should help local health professionals to obtain additional information on the rapid and silent circulation of infectious agents in communities at the regional level. [ABSTRACT FROM AUTHOR]

This study was conducted to observe the possibility of long-term storage of aerobic granular sludge (AGS) for further purposes. The research was done by drying the AGS and then stored in zip-lock bags placed in the laboratory and storage room. The AGS stored for 1 day in the laboratory, 1 week, and 1 month in both locations. The AGS then reactivated after each storage period, ran for 1 day, then performed analysis. After that, the reactivated AGS was redried to store for the next storing experiment. The analysis indicates that granules become darker and smaller in every reactivation by the size could reduce up to 28% after several time of drying and reactivating which is vice versa to granules settling velocity where it could increase up to 25% after storage. The granules stored for 1 day has the slightest effect on removal performance. Storing granules in a fluctuating temperature condition is possible but should not exceed 1 week. Although the removal performance dropped, it has the possibility to recover after the aerobic granular sludge was running continuously for a period. [ABSTRACT FROM AUTHOR]