Assessment of drugs of abuse in a wastewater treatment plant in New Zealand with parallel secondary wastewater treatment train

In this study, 24-hour composite wastewater samples were collected from a wastewater treatment plant of New Zealand with parallel secondary treatment units. The aim was to investigate the occurrence, removal, and consumption of 13 drugs of abuse (DOAs) including illicit drugs, alcohol, nicotine, and their metabolites. The filtered samples were analysed through direct injection on LC-MS/MS. Ethyl sulfate, one of the major metabolites of alcohol, was detected at the highest concentration (mean = 8300 ng/L) in wastewater influent. The mean concentrations of methamphetamine and hydroxycotinine in the influent were found to be 935 ng/L and 5000 ng/L, respectively. Amphetamine (383 ng/L) and cocaine (286 ng/L) were detected at the highest concentrations in the effluent. The removal efficiency of the treatment plant varied for DOAs: >99% for morphine, ethyl sulfate, and hydroxycotinine an

A review of polymeric membranes and processes for potable water reuse

Conventional water resources in many regions are insufficient to meet the water needs of growing populations, thus reuse is gaining acceptance as a method of water supply augmentation. Recent advancements in membrane technology have allowed for the reclamation of municipal wastewater for the production of drinking water, i.e., potable reuse. Although public perception can be a challenge, potable reuse is often the least energy-intensive method of providing additional drinking water to water stressed regions. A variety of membranes have been developed that can remove water contaminants ranging from particles and pathogens to dissolved organic compounds and salts. Typically, potable reuse treatment plants use polymeric membranes for microfiltration or ultrafiltration in conjunction with reverse osmosis and, in some cases, nanofiltration. Membrane properties, including pore size, wettability, surface charge, roughness, thermal resistance, chemical stability, permeability, thickness and mechanical strength, vary between membranes and applications. Advancements in membrane technology including new membrane materials, coatings, and manufacturing methods, as well as emerging membrane processes such as membrane bioreactors, electrodialysis, and forward osmosis have been developed to improve selectivity, energy consumption, fouling resistance, and/or capital cost. The purpose of this review is to provide a comprehensive summary of the role of polymeric membranes and process components in the treatment of wastewater to potable water quality and to highlight recent advancements and needs in separation processes. Beyond membranes themselves, this review covers the background and history of potable reuse, and commonly used potable reuse process chains, pretreatment steps, and advanced oxidation processes. Key trends in membrane technology include novel configurations, materials, and fouling prevention techniques. Challenges still facing membrane-based potable reuse applications, including chemical and biological contaminant removal, membrane fouling, and public perception, are highlighted as areas in need of further research and development. Keywords: Potable reuse; Polymeric membranes; Reverse osmosis; Filtration; Fouling; Revie

Retrieving back plastic wastes for conversion to value added petrochemicals: opportunities, challenges and outlooks

Plastic production and its unplanned management and disposal, has been shown to pollute terrestrial, aquatic, and atmospheric environments. Petroleum-derived plastics do not decompose and tend to persist in the surrounding environment for longer time. Plastics can be ingested and accumulate into the tissues of both terrestrial and aquatic animals, which can impede their growth and development. Petrochemicals are the primary feedstocks for the manufacture of plastics. The plastic wastes can be retrieved back for conversion to value added petrochemicals including aromatic char, hydrogen, synthesis gas, and bio-crude oil using various technologies including thermochemical, catalytic conversion and chemolysis. This review focusses on technologies, opportunities, challenges and outlooks of retrieving back plastic wastes for conversion to value added petrochemicals. The review also explores both the technical and management approaches for conversion of plastic wastes to petrochemicals in regard to commercial feasibility, and economic and environmental sustainability. Further, this review work provides a detailed discussion on opportunities and challenges associated with recent thermochemical and catalytic conversion technologies adopted for retrieving plastic waste to fuels and chemicals. The review also recommends prospects for future research to improve the processes and cost-efficiency of promising technologies for conversion of plastic wastes to petrochemicals. It is envisioned that this review would overcomes the knowledge gaps on conversion technologies and further contribute in emerging sustainable approaches for exploiting plastic wastes for value-added products

Hydrochar: A Promising Step Towards Achieving a Circular Economy and Sustainable Development Goals

The United Nations 17 Sustainable Development Goals (SDGs) are a universal call to action to end poverty, protect the environment, and improve the lives and prospects of everyone on this planet. However, progress on SDGs is currently lagging behind its 2030 target. The availability of water of adequate quality and quantity is considered as one of the most significant challenges in reaching that target. The concept of the ‘Circular Economy’ has been termed as a potential solution to fasten the rate of progress in achieving SDGs. One of the promising engineering solutions with applications in water treatment and promoting the concept of the circular economy is hydrochar. Compared to biochar, hydrochar research is still in its infancy in terms of optimization of production processes, custom design for specific applications, and knowledge of its water treatment potential. In this context, this paper critically reviews the role of hydrochar in contributing to achieving the SDGs and promoting a circular economy through water treatment and incorporating a waste-to-value approach. Additionally, key knowledge gaps in the production and utilization of engineered hydrochar are identified, and possible strategies are suggested to further enhance its water remediation potential and circular economy in the context of better natural resource management using hydrochar. Research on converting different waste biomass to valuable hydrochar based products need further development and optimization of parameters to fulfil its potential. Critical knowledge gaps also exist in the area of utilizing hydrochar for large-scale drinking water treatment to address SDG-6

Electrochemically Mediated Reduction of Nitrosamines by Hemin-Functionalized Redox Electrodes

Nitrosamines make up a major class of contaminants of emerging concern that are toxic, present at trace levels in aqueous environments, and challenging to destroy because of their chemical stability. We report novel redox electrodes based on hemin-functionalized carbon nanotubes showing high electrocatalytic activity for nitrosamine reduction at low potentials (−0.5 V vs Ag/AgCl or −0.27 vs the standard hydrogen electrode) and with turnover numbers of >700. The redox electrodes were tested under a range of electrolyte and pH conditions and demonstrated high conversion of nitrosamines at high reaction rates, even at parts per billion levels in secondary effluent from a wastewater treatment plant. We propose that the pathway for nitrosamine reduction involves a proton-mediated conversion of the nitroso group to hydrazines and secondary amines. These high-performance biomimetic electrocatalysts for nitrosamine reduction are based on complexes containing earth-abundant metals and, potentially, have broad applications in environmental remediation, water treatment, and industrial organo-electrochemical processes

Sustainable management of hazardous asbestos-containing materials: Containment, stabilization and inertization

Asbestos is a group of six major silicate minerals that belong to the serpentine and amphibole families, and include chrysotile, amosite, crocidolite, anthophyllite, tremolite and actinolite. Weathering and human disturbance of asbestos-containing materials (ACMs) can lead to the emission of asbestos dust, and the inhalation of respirable asbestos fibrous dust can lead to ‘mesothelioma’ cancer and other diseases, including the progressive lung disease called ‘asbestosis’. There is a considerable legacy of in-situ ACMs in the built environment, and it is not practically or economically possible to safely remove ACMs from the built environment. The aim of the review is to examine the three approaches used for the sustainable management of hazardous ACMs in the built environment: containment, stabilization, and inertization or destruction. Most of the asbestos remaining in the built environment can be contained in a physically secured form so that it does not present a significant health risk of emitting toxic airborne fibres. In settings where safe removal is not practically feasible, stabilization and encapsulation can provide a promising solution, especially in areas where ACMs are exposed to weathering or disturbance. Complete destruction and inertization of asbestos can be achieved by thermal decomposition using plasma and microwave radiation. Bioremediation and chemical treatment (e.g., ultrasound with oxalic acid) have been found to be effective in the inertization of ACMs. Technologies that achieve complete destruction of ACMs are found to be attractive because the treated products can be recycled or safely disposed of in landfills

Review on distribution, fate, and management of potentially toxic elements in incinerated medical wastes

Medical wastes include all solid and liquid wastes that are produced during the treatment, diagnosis, and immunisation of animals and humans. A significant proportion of medical waste is infectious, hazardous, radioactive, and contains potentially toxic elements (PTEs) (i.e., heavy metal (loids)). PTEs, including arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg), are mostly present in plastic, syringes, rubber, adhesive plaster, battery wastes of medical facilities in elemental form, as well as oxides, chlorides, and sulfates. Incineration and sterilisation are the most common technologies adopted for the safe management and disposal of medical wastes, which are primarily aimed at eliminating deadly pathogens. The ash materials derived from the incineration of hazardous medical wastes are generally disposed of in landfills after the solidification/stabilisation (S/S) process. In contrast, the ash materials derived from nonhazardous wastes are applied to the soil as a source of nutrients and soil amendment. The release of PTEs from medical waste ash material from landfill sites and soil application can result in ecotoxicity. The present study is a review paper that aims to critically review the dynamisms of PTEs in various environmental media after medical waste disposal, the environmental and health implications of their poor management, and the common misconceptions regarding medical waste

The potential of biochar as a microbial carrier for agricultural and environmental applications

Biochar can be an effective carrier for microbial inoculants because of its favourable properties promoting microbial life. In this review, we assess the effectiveness of biochar as a microbial carrier for agricultural and environmental applications. Biochar is enriched with organic carbon, contains nitrogen, phosphorus, and potassium as nutrients, and has a high porosity and moisture-holding capacity. The large number of active hydroxyl, carboxyl, sulfonic acid group, amino, imino, and acylamino hydroxyl and carboxyl functional groups are effective for microbial cell adhesion and proliferation. The use of biochar as a carrier of microbial inoculum has been shown to enhance the persistence, survival and colonization of inoculated microbes in soil and plant roots, which play a crucial role in soil biochemical processes, nutrient and carbon cycling, and soil contamination remediation. Moreover, biochar-based microbial inoc-ulants including probiotics effectively promote plant growth and remediate soil contaminated with organic pollutants. These findings suggest that biochar can serve as a promising substitute for non-renewable substrates, such as peat, to formulate and deliver microbial inoculants. The future research directions in relation to improving the carrier material performance and expanding the potential applications of this emerging biochar-based microbial immobilization tech-nology have been proposed.Peer reviewe

Recovery, regeneration and sustainable management of spent adsorbents from wastewater treatment streams:A review

Adsorption is the most widely adopted, effective, and reliable treatment process for the removal of inorganic and organic contaminants from wastewater. One of the major issues with the adsorption-treatment process for the removal of contaminants from wastewater streams is the recovery and sustainable management of spent adsorbents. This review focuses on the effectiveness of emerging adsorbents and how the spent adsorbents could be recovered, regenerated, and further managed through reuse or safe disposal. The critical analysis of both conventional and emerging adsorbents on organic and inorganic contaminants in wastewater systems are evaluated. The various recovery and regeneration techniques of spent adsorbents including magnetic separation, filtration, thermal desorption and decomposition, chemical desorption, supercritical fluid desorption, advanced oxidation process and microbial assisted adsorbent regeneration are discussed in detail. The current challenges for the recovery and regeneration of adsorbents and the methodologies used for solving those problems are covered. The spent adsorbents are managed through regeneration for reuse (such as soil amendment, capacitor, catalyst/catalyst support) or safe disposal involving incineration and landfilling. Sustainable management of spent adsorbents, including processes involved in the recovery and regeneration of adsorbents for reuse, is examined in the context of resource recovery and circular economy. Finally, the review ends with the current drawbacks in the recovery and management of the spent adsorbents and the future directions for the economic and environmental feasibility of the system for industrial-scale application