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Antimicrobial resistance (AMR) is a growing threat to human and animal health.Progress in molecular biology has revealed new and significant challenges for AMR mitigation given the immense diversity of antibiotic resistance genes (ARGs), the complexity of ARG transfer, and the broad range of omnipresent factors contributing to AMR. Municipal, hospital and abattoir wastewater are collected and treated in wastewater treatment plants (WWTPs), where the presence of diverse selection pressures together with a highly concentrated consortium of pathogenic/commensal microbes create favourable conditions for the transfer of ARGs and proliferation of antibiotic resistant bacteria (ARBs). The recent emergence ARBs and ARGs as well as their potential health effects have re-defined the role of WWTPs as a focal point in the fight against AMR. By reviewing the occurrence of ARGs in wastewater and sludge and the current technologies used to quantify ARGs and identify antibiotic resistant bacteria (ARB), this paper provides a research roadmap to address existing challenges in AMR control via wastewater treatment. Wastewater treatment is a double-edged sword that can act as either a pathway for AMR spread or as a barrier to reduce the environmental release of anthropogenic AMR. State of the art ARB identification technologies, such as metagenomic sequencing and fluorescence-activated cell sorting, have enriched ARG/ARB databases, unveiled keystone species in AMR networks, and improved the resolution of AMR dissemination models. Data and information provided in this review highlight significant knowledge gaps. These include inconsistencies in ARG reporting units, lack of ARG/ARB monitoring surrogates, lack of a standardised protocol for determining ARG removal via wastewater treatments, and the inability to support appropriate risk assessment. This is due to a lack of standard monitoring targets and agreed threshold values, and paucity of information on the ARG-pathogen host relationship and potential risk evolution. These research gaps need to be addressed and research 3 findings need to be transformed into practical guidance for WWTP operators to enable effective progress towards mitigating the evolution and spread of AMR.

The flocculation efficiency of microalgae Chlorella vulgaris for subsequent harvesting was investigated using single flocculants of inorganic salts, synthetic polymer, chitosan and dual flocculants of inorganic salts and chitosan. Synthetic polymer (Flopam T M) could achieve over 90% optical density removal (OD680 removal) at a low flocculant dose (20 to 40 mg polymer per litre of algal suspension) through the bridging mechanism and charge neutralisatio n. Inorganic salts (i.e. ferric chloride and aluminium sulphate) and chitosan individually resulted in low flocculation efficiency (<90%) despite high dose (i.e. 160 to 200 mg per litre of algal suspension). The dual flocculation combining ferric chloride or aluminium sulphate with chitosan induced synergistic effects, resulting in >80% flocculation efficiency, significa nt ly higher than the sum of each individual flocculation. The improvement in flocculation efficie nc y was 57 and 24% respectively for ferric chloride/chitosan and aluminium sulphate/chitosa n. Charge neutralisation of microalgal cells by ferric chloride or aluminium sulphate combined with bridging by chitosan produced the synergy.

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Purpose of ReviewCyanobacteria, commonly known as blue-green algae, are often seen as a problem. Their accumulation (bloom) in surface water can cause toxicity and aesthetic concerns. Efforts have been made in preventing and managing cyanobacterial blooms. By contrast, purposeful cultivation of cyanobacteria can create great opportunities in food, chemical and biofuel applications. This review summarises the current stage of research and the socio-economic impacts associated with both the problems and opportunities induced from the presence of cyanobacteria in surface water. Recent FindingsInsightful knowledge of factors that trigger cyanobacterial blooms has allowed for the development of prevention and control strategies. Advanced technologies are utilised to detect, quantify and treat cyanobacterial biomass and cyanotoxins in a timely manner. Additionally, understanding of cyanobacterial biochemical properties enables their applications in food and health industry, agriculture and biofuel production. Researchers have been able to genetically modify several cyanobacterial strains to obtain a direct pathway for ethanol and hydrogen production.

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