Existing sewage treatment plants are expected to be the abundant storage and valuable source of naturally functional microorganisms for the proposed ones. This study attempted to migrate the microbial flora in a biological aerated filter (BAF) treating reverse osmosis concentrated water to a proposed BAF treating photovoltaic pickling wastewater, both systems-designed to mainly remove nitrate. The removal efficiency of nitrate nitrogen in total nitrogen increased significantly from 7.3% to 79.5% after the enriched microorganisms were inoculated into the pilot plant. Subsequently, the effluent was stably controlled to meet the required standards (ammonium nitrogen < 35 mg/dm3, total nitrogen < 45 mg/dm3) in the practical engineering. The enrichment of the important denitrifying and phosphorus-accumulating genus Thauera and the genus Flavobacterium involved in the nitrogen cycle was observed as one of the important reasons for performance improvement. This study is expected to provide theoretical guidance for the efficient control of industrial sewage.
The water quality of the Chaobai River in Langfang section is relatively poor throughout the year. The water environmental capacity is almost zero, and the surface water is severely polluted, with ammonia nitrogen, total phosphorus, and chemical oxygen demand identified as the primary pollution indicator. This study adopts MIKE11 software to simulate and analyze the water quality and water quantity dynamics of the Langfang section of the Chaobai River. Model parameters are meticulously calibrated and rigorously verified based on the measured hydrological and water quality data collected from the river. The simulation results effectively reflect the actual spatiotemporal characteristics of water quality and quantity within the river reach. The findings of this research can provide a reliable scientific basis and strong technical support for the comprehensive improvement of the ecological environment and the restoration of water functions in the Langfang section of the Chaobai River, thereby contributing to the sustainable development of the regional water ecosystem.
Expansive soils present major geotechnical challenges due to their pronounced swell–shrink behaviour and associated volumetric instability, which can compromise foundations, pavements, and embankments. This study examines the stabilization of Ankara expansive clay using eight conventional, chemical, and waste-derived additives through a structured two-stage laboratory program. In Stage 1, all stabilizers were applied at a uniform dosage of 30% by dry weight and evaluated in terms of index properties, Standard Proctor compaction characteristics, and one-dimensional swelling behaviour. The results show that stabilizer type strongly governs the moisture–density relationship and swelling response. Composite systems, particularly concrete demolition waste (CDW) combined with lime or gypsum and cement–gypsum blends, achieved the greatest reductions in plasticity and swell potential, whereas gypsum alone exhibited limited effectiveness. Based on Stage-1 performance, lime and CDW were selected for Stage-2 testing at 10% and 20% dosages. A clear dosage-dependent response was observed: CDW slightly outperformed lime at lower dosage due to mechanical restraint and particle interlocking, while lime showed marginally superior swell suppression at higher dosage through intensified physicochemical reactions. Both stabilizers significantly enhanced shear strength via distinct mechanisms. The findings highlight the effectiveness of waste-derived and hybrid stabilization strategies for sustainable expansive soil improvement.
The ongoing energy transition has led to a systematic increase in the use of lithium-ion batteries, resulting in a growing stream of waste generated at the end of their life cycle. Due to the presence of residual energy and complex material composition, spent lithium-ion cells constitute a significant environmental and technological challenge. This study investigates thermal processes occurring in mechanically damaged cylindrical 18650 NMC lithium-ion cells based on temperature measurements and mass changes before and after the experiment. The experimental procedure included measurements of resting voltage, initial mass determination, and controlled mechanical damage using a puncture method. Surface temperature changes were monitored using thermal imaging techniques. The results demonstrated rapid initiation of thermal processes accompanied by intensive emission of decomposition products and significant mass loss. Maximum surface temperatures reached 790°C, while the relative mass loss ranged from 25.7% to 43.8% of the initial cell mass, indicating intensive release of volatile decomposition products. The obtained results underline the importance of safe collection, storage, and management of spent lithium-ion batteries in the context of environmental protection and waste management.
This study applied China's provincial panel data from 2007 to 2023 and the Generalized Additive Model (GAM) to examine the nonlinear driving mechanisms of general industrial solid waste generation (GISWG). The results showed that China's GISWG reached a negative growth inflection point in 2016, and the influencing factors exhibit significant nonlinear characteristics. Specifically, per capita GDP (PCGDP) presents an inverted U-shaped trajectory, with a critical turning point identified at approximately 135,000 CNY per person, validating the existence of the Environmental Kuznets Curve (EKC). Moreover, industrial added value (IAV) shows oscillating fluctuations, while main business revenue of industrial enterprises (MBRIE) demonstrates diminishing marginal effects beyond the threshold of 11 trillion CNY. Technological innovation exhibits a U-shaped pattern, signaling a transition from substantive mitigation to a potential rebound effect once domestic patent applications exceed 400,000 items. Spatially, the impact of economic factors is primarily concentrated in developed and heavy-industrial regions, while governance factors vary significantly across regions. This study provides empirical evidence for identifying governance thresholds and offers actionable strategies for Zero-waste City construction.
