Heavy metal contamination in water and soil has gradually become a concern with the development of industry in recent years and may pose a serious threat to human health if left untreated. Biochar is commonly used as an adsorbent/immobilizer of heavy metals from water and substrates because of its wide—ranging raw materials, low production cost, and good adsorption performance. Based on the adsorption mechanism of biochar, this paper analyzes different modification methods of biochar, aiming to provide an effective material for the treatment of heavy metals from water and sediment and provide a certain reference for its application to practical projects.

Widespread exposure to organophosphorus flame retardants (OPFRs) has been observed in the general population. Emerging studies have revealed OPFRs possess endocrine-disturbing properties. The present study aims to assess the association between urinary metabolites of OPFRs, BMI, and serum lipid profiles. Data from the National Health and Nutrition Examination Survey (NHANES) 2017–2018 were obtained, with 1334 adults enrolled in the current study. Urinary concentrations of bis (1-chloro-2-propyl) phosphate (BCIPP), bis(2-chloroethyl) phosphate (BCEP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), dibutyl phosphate (DBUP), and diphenyl phosphate (DPHP) were quantified to assess OPFR exposure. Covariate-adjusted linear and logistic regression models were conducted to explore the associations between log₂-transformed concentrations of OPFR metabolites, BMI, obesity, and serum lipid profiles. Stratified analyses were performed to assess the heterogeneity of associations by age, gender, race, etc. Positive associations were found between OPFR exposure and the risk of obesity. The multivariate linear analysis indicated that a one-unit increase in log₂-transformed urinary concentrations of BCEP and BDCPP was associated with 0.27 (95% CI: 0.02–0.52, p = 0.0338) and 0.56 (95% CI: 0.25–0.87, p = 0.0004) higher BMI value, respectively. One log₂-unit increase in urinary BCEP and BDCPP concentrations was associated with 1.1-fold (95% CI: 1.02–1.18, p = 0.0096) and 1.19-fold (95% CI: 1.09–1.30, p = 0.0001) risk for developing obesity. Furthermore, the non-linear relationship between exposure to OPFRs and obesity was identified. Additionally, multivariable linear regression showed that urinary DPHP concentrations were inversely correlated with serum triglyceride (TG) levels (β = −7.41, 95% CI: −12.13 to −2.68, p = 0.0022). However, no other OPFR metabolites were found to be significantly statistically associated with serum lipid levels after adjusting for potential confounders. In conclusion, environmental exposure to OPFRs might contribute to obesity and dysregulated TG concentrations in adults. Future prospective research is warranted to confirm the causal relationship between metabolites of OPFRs and obesity.

With the development of industry in recent years, heavy metal contamination in water and substrate, which may pose a serious threat to human health if left untreated, has attracted increasing attention. Biochar is commonly used as an adsorbent/immobilizer for heavy metals in water and substrates because of its wide range of raw materials, low production cost, and good adsorption performance. In this paper, we selected abundant Moso bamboo as the raw material to make biochar (bamboo charcoal), modified bamboo charcoal using different methods to find the modified product with the best adsorption effect, assessed the adsorption performance of modified bamboo charcoal on Cu(II) and Cd(II) in solution, and investigated the effects of the solution concentration, adsorption time, pH, and temperature on the adsorption effect of KAM500-400-3 on Cu(II) and Cd(II). The effect of the solution concentration, adsorption time, pH, and temperature on the adsorption effect of KAM500-400-3 on Cu(II) and Cd(II) was investigated, and the adsorption mechanism of KAM500-400-3 on heavy metals Cu(II) and Cd(II) was analyzed by fitting the adsorption kinetics, adsorption isotherms, and adsorption thermodynamics. The adsorption/fixation characteristics of modified bamboo charcoal on heavy metals Cu(II) and Cd(II) in water and substrate were investigated. This study aimed to identify an effective material for the treatment of heavy metals in water and substrates and provide a reference for their application in practical engineering.

In recent years, the production of municipal sludge has gradually increased, and finding suitable sludge treatment and disposal technologies is an urgent problem that needs to be solved. Bio-drying of sludge is a relatively efficient and convenient drying method, but currently, there are still problems with unstable drying effects and high moisture content of dried products, which limits the subsequent utilization of bio-drying products. This article uses a thermal assisted bio-drying device that simulates carbonization waste heat reflux, and uses corncob, straw, sawdust, and rice husk as conditioners to carry out bio-drying of dehydrated sludge. The influence of the types and ratios of conditioner under thermal assistance on the bio-drying of dehydrated sludge is explored. The results showed that the moisture removal efficiency of the corncob and straw groups was better, and their material moisture content could be reduced to below 10% within 24 h. The lower calorific value of straw-sludge drying products was the highest, at 11,608.8 kJ/kg. The best conditioner under the conditions of this experiment was straw, and the drying effect was best when the mass ratio of dehydrated sludge to straw was 4:1. The research results contribute to promoting the development of sludge bio-drying technology.

In this study, we studied the influence of the dosage of modified bamboo charcoal (KAM-500-400-3) on the fixation effect of single Cu(II)-contaminated and mixed Cu(II)–Cd(II)-contaminated sediment. The results showed that it could effectively fix the heavy metals in both sediment types. In the single Cu(II)-contaminated sediment, when the amount of added KAM500-400-3 was greater than or equal to 5%, the Cu(II) content in the overlying and pore water was substantially reduced, and the form of heavy metal Cu(II) in the sediment changed from the acid-extractable state to a relatively stable, reducible, oxidizable, and residual state, its bioavailability markedly reduced, and the toxic leaching amount of heavy metal TCLP in the sediment also gradually reduced. In the sediment polluted by Cu(II)–Cd(II), the Cu(II) and Cd(II) could not be detected in the overlying or pore water when the addition amount was greater than or equal to 2.5%. The contents of Cu(II) and Cd(II) in the acid-extractable state considerably decreased and they transformed into other forms with low bioavailability, in which the content of Cd(II) in the oxidizable state was so low that it was lower than the detection limit. The TCLP toxicity of the leached amount of Cd(II) also gradually decreased. This showed that adding KAM500-400-3 to sediment helps with inhibiting the release of heavy metals from contaminated sediment into water bodies, so KAM500-400-3 is a material that can effectively adsorb and fix heavy metals Cu(II) and Cd(II) in sediment.

Aiming at the problem of low pollutant concentration in the sewage treatment plant due to external water intrusion into the sewage collection system, which in turn leads to low pollutant reduction efficiency. A sewage system in Zhenjiang City is taken as an example. Analyze the situation of external water intrusion in the sewage pipe network and determine the external water intrusion proportion based on the water quality and quantity method. First, the dry season flow rate of the sewage pipe is obtained according to the monitoring data of the flowmeter. Then, the key research areas are screened out based on the changes in the concentration of water quality characteristic factors. Furthermore, chemical oxygen demand and electrical conductivity are used as water quality characteristic indicators to characterize shallow groundwater and river water. In addition, the proportions of groundwater and river water intrusion in the sewage pipe network are quantitatively analyzed based on the chemical mass balance equation. At the same time, the dredging detection method is used to assist in the investigation, and finally, the engineering rectification of the problems found in the drainage is carried out. The results show that the water quality and quantity method can effectively identify the types of external water and analyze the proportion of external water intrusion, which is of exemplary significance for the evaluation of sewage collection systems.