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Abstract A pilot-scale anaerobic co-digestion research study is presented to elucidate the feasibility of developing anaerobic digestion (AD) as an effective disposal method for municipal biomass waste (MBW) in China, focusing on biogas production and greenhouse gas (GHG) reduction. Food waste, fruit–vegetable waste, and dewatered sewage sludge were co-digested in a continuous stirred-tank reactor for biogas production. Stable operation was achieved with a high biogas production rate of 4.25 m3 (m3 d)−1 at organic loading rate of 6.0 kgVS (m3 d)−1 and hydraulic retention time of 20 d. A total of 16.5% of lipids content was beneficial to the biogas production of the feedstock without inhibition to anaerobic digestion. Compared with the landfill baseline, GHG reduction is an important environmental benefit from MBW digestion. Therefore, anaerobic co-digestion is a promising alternative solution for MBW because it contributes significantly to the sound management of municipal solid waste in China.

Nitrogen (N), phosphorus (P), and potassium (K) represent the primary components of commercial NPK fertilizer and are primarily derived from finite resources through complex and expensive processes. To ensure global food security, the development of sustainable and eco-friendly procedures for fertilizer production has gained attention. Humans generally excrete urine containing 11 g of N/L, 0.3 g of P/L of P and 1.5 g of K/L, which benefit plant growth. The recovery of these essential plant nutrients from human urine has become the focal point of increasing research endeavors. Despite the potential advantages of nutrient recovery from urine, this process is complicated, and the economic implications are substantial. Furthermore, human urine may harbor undesirable contaminants, such as pathogens, pharmaceutical residues, hormones, and elevated salt levels, which could be disseminated into the environment through agriculture. This study appraised various emerging technologies for nutrient recovery from human urine, considering their challenges, environmental impact, economic viability, and the overall sustainability of the processes. This review elucidated that most nutrient recovery technologies demonstrated elevated efficiency in nutrient recovery. Nevertheless, a recurrent oversight involves neglecting the potential transfer of contaminants and pathogens into environmental matrices. The complexity of these processes and their economic feasibility vary, with some proving intricate and economically unviable. Given that no singular technology fully mitigates these challenges, integrating two or more technologies appears imperative to address drawbacks and enhance overall system performance.

A concept has been proposed for an installation designed to store excess electricity periodically occurring on the grid. Excess electricity will be used for straw pyrolysis. The main pyrolysis product, gas, will be used to generate electricity using a combustion generator to feed back power into the grid during periods of shortage. The resulting biochar from the pyrolysis can be introduced into the soil to improve soil quality and play a significant role in carbon sequestration. The system uses an electrically heated reactor with a screw conveyor. To preliminarily assess the feasibility of this system, experiments were carried out using wheat straw at temperatures of 300, 400, 500, 600, and 700 °C for the pyrolysis reactor. The resulting gas-to-feedstock mass ratio ranged from 29.04 % at 300 °C to 52.7 % at 700 °C reactor temperature, the biochar mass yield ratio to feedstock varied from 39.41 % to 27.36 % (at 700 °C), and the pyrolysis liquid ranged from 31.55 % to 27.36 % (at 700 °C). The pyrolytic liquid contained a high water content relative to its mass, reaching up to 95.2 % at 700 °C, rendering it less suitable as an energy feedstock. At a reactor temperature of 700 °C, the energy value of the gas produced from the feedstock was twice that of the electricity used for the pyrolysis process. These results suggest the feasibility and operation of the proposed installation.

The current organization of water supply systems demands drinking standards for all the households’ usage of water. Few dual water systems, i.e., systems in which the quality of the water supplied is differentiated by types of use, exist but are mainly circumscribed to developing countries. Besides, bath and showers are so far considered as a potable use of water despite only drinking and cooking activities requiring the high-quality standards of potable water. The present work demonstrates how the principles of dual water systems can be incorporated into the sustainable concept of product-service system (PSS) using a dual water system of a municipal water supply treatment plant in France as a case study. The PSS is based on the water quality, and the bathing activity of households is considered with a dedicated standard for the first time. Two systems are considered, S1 and S2, supplied with the same raw water quality and treated with drinking (S1) bathing standards (S2). The quality parameters considered are total organic carbon (TOC) and turbidity (T) and the potential savings related to costs, material, and energy consumptions are assessed using EVALEAU as a process modeling tool. The treatment lines consisted of powdered activated carbon (PAC) addition, coagulation, flocculation, settling, and rapid sand filtration. Results show that material consumption can be reduced by 41% mainly through the decrease in chemical consumption associated with the change of requirement for the TOC parameter. On the opposite, energy consumption was found dependent on the water of volume treated rather than its quality leading to only marginal savings. The cost was decreased by 37% as a result of the reduction of the chemicals consumed.

Marine organisms are constantly exposed to multiple stressors creating a range of associated environmental and ecotoxicological risks. Several stressors have been identified as key drivers of environmental change that may significantly influence marine near-shore systems. These include increased frequency and duration of extreme rainy events and drought periods, arising from climate change, and the constant discharge of contaminants into aquatic systems. A growing body of evidence demonstrates that climate change can have direct and indirect impacts on marine organisms although the combined effects with other stressors, namely with metals and metalloids, have received very little attention to date. The present study evaluated the biochemical alterations induced in the clam Ruditapes philippinarum, also known as Manila clam, when simultaneously exposed (96 h) to different arsenic concentrations (0, 4 and 17 mg/L) and a range of salinities (14, 21, 28, 35 and 42 g/L). Results obtained revealed that, when acting alone, both stressors induced oxidative stress in clams, with higher LPO levels and lower GSTs activity induced by As contamination, and a stronger inhibition of the antioxidant defenses induced by salinity increase. Furthermore, when exposed to the combination of both stressors, clams experienced stronger biochemical alterations, presenting higher LPO increases and greater decreases of antioxidant enzymes, especially noticed at higher salinities. The present findings may indicate that climate change, including predicted drought periods that will increase salinities in aquatic systems, will seriously affect the clam R. philippinarum, especially those inhabiting contaminated ecosystems.

Nitrite removal is necessary and significant for pickle and meat processing wastewater. In this study, Chlorella sp. L38 is used as an alternative to remove nitrite and reuse it as nitrogen source for potential value-added ingredients production. Based on the typical BG11 medium with and without NaNO3 (which is the conventional nitrogen source), nitrite is additionally provided, and its concentration gradient was set at 0, 50, 100, 150 and 200 μmol/L, respectively. The experimental results showed that the nitrite removal rate could achieve 57.1 μmol/L/d. In addition, the biomass variation, and value-added ingredients (polysaccharides, lipid, and protein) productivity were also measured, and their yield could achieve 4.8 mg/g/d, 3.0 mg/L/d and 5.5 mg/L/d, respectively. It indicated that Chlorella sp. L38 has the potential to be an environmentally friendly approach for nitrite removal of wastewater.

In this study, the problem of frost penetration in high-clay content soils is examined with the view to assessment of cyclic freeze-thaw effects on initial virgin unfrozen natural clays. The requirements for control of the frost-heave problem in many construction projects in the northern regions of Eastern Canada demand that proper prediction be made for both frost-heave pressures and magnitudes of frost heaving in the high-clay content soils. Laboratory cyclic freeze-thaw and frost-heave tests conducted have shown that the mechanical properties of the clay soils, which are virgin unfrozen natural soil samples obtained from Northern Quebec, are sensitive to cyclic freeze-thaw. In the cyclic freeze-thaw tests conducted, scanning electron micrographs taken from samples after various cycles show that the original soil fabric becomes more disturbed after the first few cycles. Particles are re-arranged, and a regrouping of particles into larger stable (or apparently stable) soil fabric units are formed after a certain number of cycles. In essence, this study provides the experimental information concerning the cyclic freeze-thaw effects on mechanical properties for some high-clay content soils, not initially subject to freezing.

Water-soluble dyes are a common problem in wastewater treatment, requiring highly efficient methods for removal. In this study, novel sustainable adsorbents made from graphene-oxide (GO) and other materials, such as eggshell-derived calcium oxide nanoparticles (CaONPs-ES), fish bone calcium oxide nanoparticles (CaONPs-FB), and durian shell activated carbon (DSAC) were synthesized, characterized, and demonstrated for soluble dye removal from wastewater. Fermented maize grain extract (MES) was used as a green cross-linker in the synthesis process. The resulting nanocomposites, GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC, showed promising adsorption capabilities for methylene blue (MB) dye removal from aqueous environments. The prepared nanocomposites (GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC) were characterize using state-of-art instrumental techniques. The BET measurement revealed that the nanocomposites surface areas were enhanced due to the cross-linking phenomenon, improving their adsorption capability towards MB dye treatment. The adsorption data of GO@CaONPs-FB/DSAC and GO@CaONPs-ES/DSAC was well fitted to the Harkins-Jura and Freundlich models, respectively. The maximum sorption capacities of GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC were 1274.5 and 689.7 mg/g, respectively. The MB dye removal mechanism was driven by π-π interaction, hydrogen bonding, electrostatic attraction and physical interactions and the adsorption process of the nanocomposites followed pseudo-second-order kinetics. The adsorptive performance of the nanocomposites was stable, showing ∼96.45 % and ∼85.18 % after 10 successive cycles for GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC respectively. Cost evaluation revealed that bulk synthesis of GO@CaONPs-ES/DSAC and GO@CaONPs-FB/DSAC nanocomposites is cost-effective for treating large quantities of MB contaminated water and other potential dyes as well. Finally, the independent and synergetic contributions between pH, adsorbent dosage and temperature on MB removal by GO@CaONPs-ES/DSAC and ...