Phosphorus circular economy of disposable baby nappy waste: Quantification, assessment of recycling technologies and plan for sustainability.

This study assessed the potential for minimizing human excreta bound phosphorus (P) loss through used disposable baby nappies, an area that remained unexplored for nations. Accordingly, it performed a substance flow analysis to assess the national P loss through used disposable baby nappies in the case of Australia. The analysis revealed that approximately 308 tonne P is lost through used baby nappies to landfills in Australia in 2019, which is nearly 2.5% of the overall P excreta as human waste. Although the quantity seems small in percentage term, it could result in the loss of a significant amount of P over several years, as assessed 5452 tonne P over the 2001-2019 period, which is concerning in the context of anticipated future global P scarcity. The review of peer-reviewed literature on available technologies/methods for recycling disposable baby nappy waste indicates that there are some technologies for recycling P particularly through co-composting with food and other organic wastes, while the majority of these are still at the lab/pilot scale. There are also various recycling techniques with purpose ranging from energy recovery to volume reduction, generation of pulp, hydrogel, cellulose, and polymer as well as to increase yield stress and viscosity of concrete, however, these are not effective in P recovery. The study implies that compost made of nappy waste can be used as fertilizer to produce bamboo, cotton, and maize plants to supply raw materials for producing biodegradable nappies, hence, to close the loop. The various product and system design options e.g., designing for flushing, designing for disassembling the excreta containing part, and designing for community composting suggested in this study could be further researched for identifying best suitable option to achieve P circular economy of disposable baby nappies. This study also recommends necessary interventions at various stages of the nappy life cycle to ensure sustainable management of phosphorus.

Environmental externalities of the COVID-19 lockdown: Insights for sustainability planning in the Anthropocene.

The COVID-19 pandemic has abruptly halted the Anthropocene's ever-expanding reign for the time being. The resulting global human confinement, dubbed as the Anthropause, has created an unprecedented opportunity for us to evaluate the environmental consequences of large-scale changes in anthropogenic activities. Based on a methodical and in-depth review of related literature, this study critically evaluates the positive and negative externalities of COVID-19 induced lockdown on environmental components including air, water, noise, waste, forest, wildlife, and biodiversity. Among adverse impacts of the lockdown, increased amount of healthcare waste (300-400%), increased level of atmospheric ozone (30-300%), elevated levels of illicit felling in forests and wildlife poaching were prominent. Compared to the negative impacts, significant positive changes in various quality parameters related to key environmental components were evident. Positive impacts on air quality, water quality, noise level, waste generation, and wildlife were apparent in varying degrees as evaluated in this study. By presenting a critical overview of the recommendations given in the major literature in light of these documented impacts, this paper alludes to potential policy reforms as a guideline for future sustainable environmental management planning. Some of the key recommendations are e.g., enhance remote working facilities, cleaner design, use of internet of things, automation, systematic lockdown, and inclusion of hazardous waste management in disaster planning. The summarized lessons of this review, pertinent to the dynamic relationship between anthropogenic activities and environmental degradation, amply bring home the need for policy reforms and prioritization of Sustainable Development Goals in the context of the planetary boundaries to the environmental sustainability for a new post-pandemic world.

Urban metabolism of phosphorus in the food production-consumption system of Bangladesh.

Anthropogenic disruption of the global phosphorus (P) cycle has already pushed it beyond the planetary boundary. Understanding P metabolism at global, regional and local scales is critical to close the loop of P for the safekeeping of mankind. Investigating the effects of urbanization-induced income growth on the natural nutrient (especially P) cycles contribute to that end. Bangladesh, a lower-middle-income agrarian economy seeing rapid urbanization and stunning GDP growth, presents itself as a good case for P-metabolism research. Past efforts to quantify P flows in the country have not addressed the effects of urbanization thereon. This time-series study quantifies the P flows in rural and urban Bangladesh using substance flow analysis after outlining the urbanization indicators (viz. GDP, income per capita, percentage of income spent on food, change in urban population and built-up area) which affects urban metabolism of P. Urbanization caused a dietary transition from cereal-based to animal-based diet resulting in 50% more P consumption from the latter by urban individuals than their rural counterparts in 2010. Comparing the P flows among the 19 expenditure groups of the urban population, an individual belonging to a higher expenditure group (USD 71-82) consumed 38% more P than one of the lower groups (USD 17-21) in 2016. Future forecasting was conducted for (i) future demand of P fertilizer using human appropriation of net primary productivity (HANPP) and (ii) P recovery potential from urban household food waste for the policymakers to get a glimpse of the future demand and recovery potential of P. The projections suggested approximately 145% rise in the national P inflow by 2030. Moreover, the universal adoption of source separation of household food waste in the two largest cities of Bangladesh can cycle back almost 1.2 × 103 tonnes of P to the system by 2030. As Bangladesh poises to faster economic growth in decades ahead, the study provides a basis for policy formulation for an appropriate P management plan to achieve circularity in nutrient use.

Magnitude of anthropogenic phosphorus storage in the agricultural production and the waste management systems at the regional and country scales.

Based on a systematic review of 17 recent substance flow analyses of phosphorus (P) at the regional and country scales, this study presents an assessment of the magnitude of anthropogenic P storage in the agricultural production and the waste management systems to identify the potential for minimizing unnecessary P storage to reduce the input of P as mineral fertilizer and the loss of P. The assessment indicates that in case of all (6) P flow analyses at the regional scale, the combined mass of annual P storage in the agricultural production and the waste management systems is greater than 50 % of the mass of annual P inflow as mineral fertilizer in the agricultural production system, while this is close to or more than 100 % in case of half of these analyses. At the country scale, in case of the majority (7 out of 11) of analyses, the combined mass of annual P storage in the agricultural production and the waste management systems has been found to be roughly equivalent or greater than 100 % of the mass of annual P inflow as mineral fertilizer in the agricultural production system, while it ranged from 30 to 60 % in the remaining analyses. A simple scenario analysis has revealed that the annual storage of P in this manner over 100 years could result in the accumulation of a massive amount of P in the agricultural production and the waste management systems at both the regional and country scales. This study suggests that sustainable P management initiatives at the regional and country scales should put more emphasis on minimizing unwanted P storage in the agricultural production and the waste management systems.

A novel substance flow analysis model for analysing multi-year phosphorus flow at the regional scale.

Achieving sustainable management of phosphorus (P) is crucial for both global food security and global environmental protection. In order to formulate informed policy measures to overcome existing barriers of achieving sustainable P management, there is need for a sound understanding of the nature and magnitude of P flow through various systems at different geographical and temporal scales. So far, there is a limited understanding on the nature and magnitude of P flow over multiple years at the regional scale. In this study, we have developed a novel substance flow analysis (SFA) model in the MATLAB/Simulink® software platform that can be effectively utilized to analyse the nature and magnitude of multi-year P flow at the regional scale. The model is inclusive of all P flows and storage relating to all key systems, subsystems, processes or components, and the associated interactions of P flow required to represent a typical P flow system at the regional scale. In an annual time step, this model can analyse P flow and storage over as many as years required at a time, and therefore, can indicate the trends and changes in P flow and storage over many years, which is not offered by the existing regional scale SFA models of P. The model is flexible enough to allow any modification or the inclusion of any degree of complexity, and therefore, can be utilized for analysing P flow in any region around the world. The application of the model in the case of Gippsland region, Australia has revealed that the model generates essential information about the nature and magnitude of P flow at the regional scale which can be utilized for making improved management decisions towards attaining P sustainability. A systematic reliability check on the findings of model application also indicates that the model produces reliable results.