Institutionalising wastewater surveillance systems to minimise the impact of COVID-19: cases of Indonesia, Japan and Viet Nam.

This mini review describes the current status and challenges regarding institutionalisation of wastewater surveillance systems against COVID-19. Monitoring SARS-CoV-2 in wastewater has been proposed to be a potential tool to understand the actual prevalence of COVID-19 in the community, and it could be an effective approach to monitor the trend during the COVID-19 pandemic. However, challenges to institutionalise wastewater surveillance systems are still abundant and unfolding at a rapid rate given that the international understanding regarding the scientific knowledge and socio-political impacts of COVID-19 are in the developing stages. To better understand the existing challenges and bottlenecks, a comparative study between Japan, Viet Nam, and Indonesia was carried out in the present study. Through gaining a better understanding of common issues as well as issues specific to each country, we hope to contribute to building a robust multistakeholder system to monitor SARS-CoV-2 in wastewater as an effective disease surveillance system for COVID-19.

Extractive membrane bioreactor (EMBR): Recent advances and applications.

Combining bioreactor and membrane, known as a membrane bioreactor (MBR), has been considered as an attractive strategy to solve the limitations of conventional activated sludge process, such as biological instability, poor sludge quality, and low concentration of mixed liquor suspended solid. Unlike the other MBRs, extractive membrane bioreactor (EMBR) focuses on enhancing the efficiency of wastewater treatment through toxic compounds extraction by using a selective membrane. Even though EMBR has been successfully demonstrated in wastewater and waste gas treatment by several studies, it still faces some obstacles such as biofilm formation and low selectivity of the membrane towards a specific component. Appropriate biofilm formation control strategies and membrane with high selectivity are needed to solve those problems. This paper reviews EMBR including its potential applications in wastewater treatment, denitrification process, and waste gas treatment. In addition, challenges and outlook of EMBR are discussed.

Palm oil mill effluent treatment and utilization to ensure the sustainability of palm oil industries.

The purpose of this study was to evaluate the current condition of palm oil mill effluent (POME) treatment and utilization and to propose alternative scenarios to improve the sustainability of palm oil industries. The research was conducted through field survey at some palm oil mills in Indonesia, in which different waste management systems were used. Laboratory experiment was also carried out using a 5 m(3) pilot-scale wet anaerobic digester. Currently, POME is treated through anaerobic digestion without or with methane capture followed by utilization of treated POME as liquid fertilizer or further treatment (aerobic process) to fulfill the wastewater quality standard. A methane capturing system was estimated to successfully produce renewable energy of about 25.4-40.7 kWh/ton of fresh fruit bunches (FFBs) and reduce greenhouse gas (GHG) emissions by about 109.41-175.35 kgCO2e/tonFFB (CO2e: carbon dioxide equivalent). Utilization of treated POME as liquid fertilizer increased FFB production by about 13%. A palm oil mill with 45 ton FFB/hour capacity has potential to generate about 0.95-1.52 MW of electricity. Coupling the POME-based biogas digester and anaerobic co-composting of empty fruit bunches (EFBs) is capable of adding another 0.93 MW. The utilization of POME and EFB not only increases the added value of POME and EFB by producing renewable energy, compost, and liquid fertilizer, but also lowers environmental burden.

Adsorption and desorption of copper(II) ions onto garden grass.

The garden grass (GG) was firstly used to remove copper(II) from water as bioadsorbent. From the results of characterisation, the GG had the merits of high specific surface area, significant adsorption sites and functional groups. Copper-adsorption significantly depends on the initial copper concentrations, contact time, pH, adsorbent doses, particle sizes and temperature. The positive values of ΔG° indicates that the adsorption of copper onto garden grass is non-spontaneous and values lies within the ranges of 4.452-13.660 kJ/mol for supporting physical adsorption. 0.1N H(2)SO(4) was found as suitable eluent, which could be used 5 cycles of adsorption-desorption. The data from adsorption and desorption equilibrium were well fitted by the Langmuir, SIPS and Redlich-Peterson isotherm models. The maximum adsorption and desorption capacities were 58.34 and 319.03 mg/g, respectively, for 1g dose. Adsorption and desorption kinetics could be described by the Pseudo-first-order model.

Hazardous waste landfill leachate treatment using an activated sludge-membrane system.

This research was aimed to investigate the capability of a combined system of activated sludge and microfiltration processes with backflushing technique to reduce organic carbon and nitrogen compounds in hazardous landfill leachates. The experiments included acclimation, batch and continuous processes. The continuous process was conducted with a 24 hour HRT (Hydraulic Retention Time), and the SRT (Solid Retention Time) ranged from 16 to 36 days. The aeration basin volume was 5 L and the membrane filter used was a hollow fiber module made from polypropylene with pore size of 0.2 microm. The batch process (without membrane separation) achieved its steady state condition over a period of 33 days. The removal of COD, BOD5 and ammonia-N were 52.5%, 94.3% and 75.5%, respectively. The kinetic parameters obtained are as followed: the maximum specific growth rate constant (microm): 0.96/day and the saturation substrate constant (Ks): 16,445.32 mg/L. The high value of Ks indicated that the leachate was not easily biodegraded. The continuous process revealed that the system with SRT of 32 days was more stable than that of 16 and 24 days. The reduction of COD, BOD5 and ammonia-N were 31.3%; 66% and 98%, respectively. The stable flux was achieved around 5 L/m2 x hour.