The study combines computational chemical modelling and practical weathering investigations, finding that computational analysis matches real-world weathering degradation across all investigated areas in a much shorter time than weathering tests.
Continuous lighting (CL) has the potential to increase crop yield in greenhouse production. Tomato plants, however, when exposed to CL develop inter-vascular chlorosis, a leaf injury which causes a reduction in chlorophyll content and necrosis. The application of biochar can reduce physiological stress in plants, we examine if biochar also reduces necrosis in tomatoes when grown under CL. Faecal sludge biochar was applied to an acidic soil to examine plant growth and yield in Micro-Tom tomato plants grown under continuous light. We examined soil and plant growth properties of three soil application treatments: a control soil, biochar treatment (4
A transition from a linear to a circular economy is the only alternative to reduce current pressures in natural resources. Our society must redefine our material sources, rethink our supply chains, improve our waste management, and redesign materials and products. Valorizing extensively available biomass wastes, as new carbon mines, and developing biobased materials that mimic nature's efficiency and wasteless procedures are the most promising avenues to achieve technical solutions for the global challenges ahead. Advances in materials processing, and characterization, as well as the rise of artificial intelligence, and machine learning, are supporting this transition to a new materials' mining. Location, cultural, and social aspects are also factors to consider. This perspective discusses new alternatives for carbon mining in biomass wastes, the valorization of biomass using available processing techniques, and the implementation of computational modeling, artificial intelligence, and machine learning to accelerate material's development and process engineering.
The pyrolysis of wet biomass such as faecal sludge and cow manure requires an extra drying step to reduce the moisture content before pyrolysis can occur. Open-air solar drying is a technique routinely used to dry faecal sludge and dairy manure. In this method water held within the biomass is lost to the atmosphere. A simple solar still was constructed in order to both dry cow manure and to capture water as part of the drying process. Measurements included solar radiation, cover temperature and internal solar still temperature and chemical analysis of the distillate. The maximum internal temperature of the solar still was recorded at 52.9 °C and the minimum recorded at 10.1 °C. The key objectives were to investigate the use of solar still technology in drying cow manure and determine the chemical properties of the distillate with a view to its re-use as irrigation water. The moisture content of the cow manure was reduced by 13%, however, the pathogen content of the resultant distillate contained 8,010 Escherichia Coli per 100 ml.
The treatment and safe disposal of sanitation waste is imperative to human health and the environment. In developed countries, the emphasis is on recovering phosphorus from municipal sewage sludge (SS) and the reduction of landfill. Whilst in developing countries, the focus is on long-term mechanisms to treat fecal sludge (FS) generated from non-sewered sanitation facilities. This chapter summarizes the thermal treatment of FS and SS via slow pyrolysis, and the resultant characterization of FS and SS-derived biochar with the aim of utilization by agriculture. In general, FS and SS biochars have high pH, ash content and macronutrient concentrations, with a low surface area and carbon content. The concentration of potentially toxic elements is a key difference between FS and SS biochars with FS biochars containing lower concentrations of these harmful metals. Assessing the properties of these biochars is challenging because of the different methods involved in the processing of raw sludge. The slow pyrolysis of FS and SS to produce biochar can play a pivotal role in a circular economy through the recovery and re-use of waste. Waste-derived biochar provides an opportunity to utilize an integrated systems-based approach to improve soil health, increase crop yield, and improve water retention.
Full-scale pyrolysis of faecal sludge in developing nations is an emerging technology for the complete removal of pathogens and the concurrent creation of biochar, a soil amendment shown to enhance crop productivity. Currently there is little information on the effects of faecal sludge biochar on soil and crop yield. Faecal sludge biochar was applied to an acidic, sandy soil to assess its effects on plant growth and yield in Micro-Tom, a model cultivar of tomato (Solanum lycopersicum L.). We examined four soil application treatments: a control soil, fertilizer treatment, biochar treatment, and a combined biochar and fertilizer treatment. The combined treatment of biochar and fertilizer together produced a tomato yield 2980% greater than the tomato yield from control soil, whereas biochar on its own increased the yield by 1060%. There was no significant difference in plant height between the combined biochar and fertilizer application and biochar on its own; however, both treatments significantly increased plant height compared to control soil. Below ground biomass showed a similar pattern, with no significant difference between biochar alone and combined biochar and fertilizer treatments, and both treatments resulted in significantly increased below ground biomass compared to control soil. The combined biochar and fertilizer treatment resulted in significantly lower water runoff than all other treatments. These findings have great potential implications for increasing food security and the creation of more sustainable agricultural practices, especially in developing regions.
The disposal of faecal sludge from non-networked sanitation amenities leads to contamination of the surrounding environment and increasing public health problems across developing countries. Permanent solutions to deal with faecal sludge are required to solve the sanitation crisis and achieve the Sustainable Development Goal (SDG) 6 “ensure availability and sustainable management of water and sanitation for all” by 2030. Full-scale pyrolysis of faecal sludge in developing countries is fast becoming a safe and long-term option. Pyrolysis not only eliminates pathogens within the sludge but produces biochar as an end product which has the potential as a soil amendment to increase crop yield. In general, faecal sludge biochars have high pH values, high ash contents, and high macro-and micronutrient concentrations. Compared to biochar from lignocellulosic materials, faecal sludge biochar contains less carbon and exhibits lower porosities, and lower surface areas. However, evaluating the properties of faecal sludge biochar is difficult due to the different technologies used in collection, storage, and transportation of the feedstock. Differences in faecal sludge characteristics based on location, climate, age of the sludge, type of sanitation technology and seasonality are also factors in determining the properties of faecal sludge biochars. These factors contribute to the difficulty in describing faecal sludge biochar properties in general terms, and there is an argument to be made that characteristics of large-scale faecal sludge biochar should be determined on a case-by-case basis. The conclusion of this review is that future research should concentrate on short-term and long-term field studies of faecal sludge biochar application to different soil types.
The continuous rise in the amount of industrial and pharmaceutical waste in water sources is an alarming concern. Effective strategies should be developed for the treatment of pharmaceutical industrial waste. Hence the alternative renewable source of energy, such as solar energy, should be utilized for a sustainable future. Herein, a series of Au plasmonic nanoparticle decorated ternary photocatalysts comprising graphitic carbon nitride and Ti3C2 MXene has been designed to degrade colourless pharmaceutical pollutants, cefixime under visible light irradiation. These photocatalysts were synthesized by varying the amount of Ti3C2 MXene, and their catalytic potential was explored. The optimized photocatalyst having 3 wt% Ti3C2 MXene achieved 64.69% removal of the pharmaceutical pollutant, cefixime within 105 min of exposure to visible light. The presence of the Au nanoparticles and MXene in the nanocomposite facilitates the excellent charge carrier separation and increased the number of active sites due to the formation of interfacial contact with graphitic carbon nitride nanosheets. Besides, the plasmonic effect of the Au nanoparticles improves the absorption of light causing enhanced photocatalytic performance of the nanocomposite. Based on the obtained results, a plausible mechanism has been formulated to understand the contribution of different components in photocatalytic activity. In addition, the optimized photocatalyst shows excellent activity and can be reused for up to three cycles without any significant loss in its photocatalytic performance. Overall, the current work provides deeper physical insight into the future development of MXene graphitic carbon nitride-based plasmonic ternary photocatalysts.
Background: The dumping of untreated faecal sludge from non-sewered onsite sanitation facilities causes environmental pollution and exacerbates poor public health outcomes across developing nations. Long-term mechanisms to treat faecal sludge generated from these facilities are needed to resolve the global sanitation crisis and realize the Sustainable Development Goal (SDG) 6 “ensure availability and sustainable management of water and sanitation for all” by 2030. Pyrolysis of faecal sludge removes pathogens and generates biochar, which can be used as a soil enhancer. Methods: The properties of faecal sludge biochars from three full-scale treatment plants in India were determined via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray (EDX) spectroscopy, crystal x-ray diffraction (XRD), proximate analyses, and BET surface area porosimetry. Results: Results showed that all three biochars had low specific surface area, high alkaline pH values, high ash content, and negative surface charge. Fourier transform infrared spectra showed the same surface functional groups present in each biochar. X-ray diffraction analysis showed the mineral composition of each biochar differed slightly. Scanning electron microscopy analysis indicated a porous structure of each biochar with ash particles evident. Conclusions: Slight differences in the ash content, surface area, pH and mineral content was observed between the three biochars.
<ns4:p><ns4:bold>Background</ns4:bold>: The dumping of untreated faecal sludge from non-sewered onsite sanitation facilities causes environmental pollution and exacerbates poor public health outcomes across developing nations. Long-term mechanisms to treat faecal sludge generated from these facilities are needed to resolve the global sanitation crisis and realize the Sustainable Development Goal (SDG) 6 “ensure availability and sustainable management of water and sanitation for all” by 2030. Pyrolysis of faecal sludge removes pathogens and generates biochar, which can be used as a soil enhancer.</ns4:p><ns4:p> <ns4:bold>Methods:</ns4:bold> The properties of faecal sludge biochars from three full-scale treatment plants in India were determined via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray (EDX) spectroscopy, crystal x-ray diffraction (XRD), proximate analyses, and BET surface area porosimetry.</ns4:p><ns4:p> <ns4:bold>Results: </ns4:bold> Results showed that all three biochars had low specific surface area, high alkaline pH values, high ash content, and negative surface charge. Fourier transform infrared spectra showed the same surface functional groups present in each biochar. X-ray diffraction analysis showed the mineral composition of each biochar differed slightly. Scanning electron microscopy analysis indicated a porous structure of each biochar with ash particles evident.</ns4:p><ns4:p> <ns4:bold>Conclusions: </ns4:bold>Slight differences in the ash content, surface area, pH and mineral content was observed between the three biochars.</ns4:p>
Full-scale pyrolysis of faecal sludge is a credible technology for the safe removal of pathogens and the concurrent creation of biochar, which has been shown to enhance crop productivity. Faecal sludge biochar has the potential to improve acidic, low nutrient soils and crop yield in developing nations more at risk of climate change and food insecurity. Little research has been conducted into public acceptance of faecal sludge biochar as a soil enhancer in agriculture. In this study of the public in Swansea, Wales, an online survey examines their awareness of, and comfort levels of eating food grown using biosolids, wood biochar and faecal sludge biochar. Our findings show that males were almost twice as likely than females to have a positive perception of biosolids (OR 1.91, p value 0.004) and faecal sludge biochar (OR 2.02, p value 0.03). Those in the oldest age group (65+) were almost five times more likely to have a positive view of faecal sludge biochar than the youngest age group (OR 4.88, p value 0.001). Deployment of faecal sludge biochar must overcome a “disgust effect” related to its human faecal origins. This factor must be centrally taken into account when implementing management and policy decisions regarding the land application of biosolids and faecal sludge biochar.
The feasibility of a solar-driven photoelectrochemical process to generate hydrogen fuel from metal mine polluted water while simultaneously recovering heavy metals has been explored.
Drying is one of the treatment techniques used for the dual purpose of safe disposal and energy recovery of faecal sludge (FS). Limited data are available regarding the FS drying process. In this paper the drying properties of FS were investigated using samples from ventilated improved pit (VIP) latrines and urine diversion dry toilets (UDDT) and an anaerobic baffle reactor (ABR) from a decentralized wastewater treatment systems. Moisture content, total solids content, volatile solids content, water activity, coupled thermogravimetry & differential thermal analysis (TGA-DTA) and calorific value tests were used to characterize FS drying. Drying kinetics and water activity measured at different moisture content during drying (100 degrees C) were similar for the samples from different on-site sanitation facilities. Experimental heat of drying results revealed that FS requires two to three times that of the latent heat of vaporization of water for drying. Drying temperature was more significant than the sludge source in determining the final volatile solids content of the dried samples. This was reinforced by the dynamic TGA that showed considerable thermal degradation (2-11% dry solid mass) near 200 degrees C. Below 200 C, the calorific value of the dried samples exhibited no significant difference. The average calorific values of VIP, UDDT and ABR samples at 100 degrees C were 14.78, 15.70, 17.26 MJ/kg dry solid, respectively. This suggests that the fuel value of FS from the aforementioned sanitation facilities will not be significantly affected by drying temperature below 200 degrees C. Based on this study, the most suitable temperature for drying of FS for a solid fuel application was found to be 150 degrees C.
Background: Drying is an important step for the thermochemical conversion of solid fuels, but it is energy-intensive for treating highly moist materials. Methods: To inform the thermal treatment of faecal sludge (FS), this study investigated the drying characteristics and kinetics of various faecal wastes using thermogravimetric analysis and isothermal heating conditions. Results: The findings show that FS from the anaerobic baffled reactor (ABR) and ventilated improved pit latrines (VIP) exhibit similar drying characteristics, with maximum drying rates at 0.04 mg/min during a constant rate period that is followed by a distinct falling rate period. On the contrary, fresh human faeces (HF) and FS from urine diversion dry toilets (UDDT) exhibited a falling rate period regime with no prior or intermittent constant rate periods. The absence of a constant rate period in these samples suggested limited amounts of unbound water that can be removed by dewatering and vice versa for VIP and ABR faecal sludges. The activation energies and effective moisture diffusivity for the sludges varied from 28 to 36 kJ/mol and 1.7·10-7 to 10·10-7 m2/s at 55°C and sludge thickness of 3mm. The Page model was consistent in modelling the different sludges across all temperatures. Conclusions: These results presented in this study can inform the design and development of innovative drying methods for FS treatment.
Drying process is one of the faecal sludge (FS) treatment techniques used for the dual purpose of safe disposal and energy recovery of FS. There is limited data is available regarding FS drying process. This work focuses on thermal drying of FS, addresses the challenges and provide scientific data that shows how research could be a transformative tool to improve technological gaps. In this work drying characteristics of FS originated from three sources (urine diversion dry toilet (UD), ventilated improved pit (Wet-VIP) and Decentralised Wastewater Treatment (DEWAT) with Anaerobic Baffled Reactors (ABR)) are presented. The effect of drying temperature (50, 105 150 and 200 °C) on the calorific value (fuel potential) of the end product were presented.
Photovoltaics (PV) are increasingly important for electrification in rural Sub-Saharan Africa, but what is the best battery technology to use? To explore this question, a small-scale domestic PV system for South Africa (20-year lifetime) to deliver 1.42 kWh electricity from batteries overnight with 10-h discharge was costed with various Li-ion, Pb-acid and Aquion aqueous hybrid ion batteries (AHIBs). Environmental impact; compatibility with circular economy; potential for cost-reduction through lifetime extension; and valorisation of batteries at end-of-life is discussed. Batteries are 81-93% of system costs, and battery production required over the system lifetime would emit 743, 674 and 6060 kg CO2-eq (Pb-acid, Li-ion and AHIBs respectively). Hazardous materials in Li-ion and Pb-acid batteries pose risks at end-of-life. Li-ion and AHIBs face potential resource supply constraints due to use of Co, Li and graphite. Closed-loop recycling and refurbishment of Pb-acid batteries is well established in South Africa. Currently, no African facilities for Li-ion or AHIB recycling exist, with little opportunity to retain material value from these batteries within the region. Despite lower efficiencies and shorter lifetimes, Pb-acid batteries, which are readily available from domestic manufacturing at low cost, are the current best choice for sustainable small-scale domestic PV systems in South Africa. (C) 2018 The Authors. Published by Elsevier Ltd.
Digital painting is an increasingly popular medium of expression for many artists, yet when compared to its traditional equivalents of physical brushes and viscous paint it lacks a dimension of tangibility. We conducted observations and interviews with physical and digital artists, which gave us a strong understanding of the types of interactions used to create both physical and digital art, and the important role tangibility plays within these experiences. From this, we developed a unique liquid-like tangible display for mobile, digital colour mixing. Using a chemical hydrogel that changes its viscosity depending on temperature, we are able to create some resemblances to the feeling of mixing paint with a finger. This paper documents the information gathered from working with artists, how this process informed the development of a mobile painting attachment, and an exploration of its capabilities. After returning with our prototype, we found that it provided artists with sensations of oil and acrylic paint mixing and also successfully mimicked how paints are laid out on a paint palette.
Shranjevanje energije : 10. mednarodna konferenca o trajnostni energiji in varstvu okolja. Deseta mednarodna konferenca o trajnostni energiji in varstvu okolja - SEEP 2017 je bila organizirana od 27. do 30. junija 2017 v Bledu, in sicer Fakulteta za kemijo in kemijsko tehnologijo Univerze v Mariboru, Slovenija in Univerza za zahod Škotske. Cilj SEEP2017 je združiti raziskave na področju trajnostne energije in varstva okolja z vsega sveta. Prispevani prispevki so združeni v 18 sej, da bi bralcem zagotovili dostop do 300 prispevkov avtorjev iz 52 državam. Zahvaljujemo se uglednim plenarnim in osrednjim govornikom ter predsednikom, ki so prijazno privolili v sodelovanje na tej konferenci. Prav tako smo hvaležni vsem avtorjem za članke in člane komisije. Menimo, da znanstveni rezultati in strokovne razprave ne bodo le spodbuda za razvoj, temveč tudi za ustvarjanje novih prijateljstev in morebitnih prihodnjih znanstvenih razvojnih projektov.
A transient finite difference thermal model based on the heat equations is developed, valid for spectrally selective surface coatings on any substrate material within a near-infrared (NIR) furnace. Spectral radiative heat transfer equivalent to a blackbody provides the heat source. Both radiative and natural convective cooling are accounted for. A Monte Carlo ray tracing algorithm is formulated and used to determine the radiation view factor. The variance of the algorithm in relation to mesh resolution and sample size is tested against published exact solutions. The radiative flux is divided into absorbed and reflected bands using hemispherical reflectance spectra measured within the 250-15,000 nm wavelength range, enabling the model to predict the thermal build-up of coatings with very different radiative properties. Results show that the transient temperature distribution of spectrally selective surface coatings within an NIR furnace can be modelled, with good agreement observed between experimental and simulated data. The model shows the expected relationship between colour and absorption, with darker coatings displaying greater absorption and heating rates than lighter coatings. Surprisingly, colours which appear similar to one another can display different heating rates, a result of their varied infrared reflectance properties.