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In order to promote the improvement of the rural living environment, the treatment of rural domestic sewage has attracted much attention in China. Meanwhile, the rural regions' sewage discharge standards are becoming increasingly stringent. However, the standard compliance rate of total phosphorus (TP) is very low, and TP has become the main limiting pollutant for the water pollutants discharge standards of rural domestic sewage treatment facilities. In this study, waste eggshell (E) was employed as a calcium source, and waste peanut shell (C) was employed as a carbon source to prepare calcium-modified biochar adsorbent materials (E-C). The resulting E-C adsorbent materials demonstrated efficient phosphate (P) adsorption from aqueous solutions over the initial pH range of 6–9 and had adsorption selectivity. At an eggshell and peanut shell mass ratio of 1:1 and a pyrolysis temperature of 800 °C, the experimental maximum adsorption capacity was 191.1 mg/g. The pseudo second-order model and Langmuir model were best at describing the adsorption process. The dominant sorption mechanism for P is that Ca(OH)2 is loaded on biochar with P to form Ca5(PO4)3OH precipitate. E-C was found to be very effective for the treatment of rural domestic sewage. The removal rate of TP in rural domestic sewage was 91–95.9%. After adsorption treatment, the discharge of TP in rural sewage met the second-grade (TP < 3 mg/L) and even first-grade (TP < 2 mg/L). This study provides an experimental basis for efficient P removal by E-C adsorbent materials and suggests possible applications in rural domestic sewage. [ABSTRACT FROM AUTHOR]

In view of the security requirements of roaming service in VANETs, an elliptic curve-based conditional privacy-preserving authentication and key agreement scheme is proposed in this paper. The anonymity of vehicle identity is realized by using XOR operation, and the traceability is achieved by embedding the public key of the local service agent into the pseudonym. The mutual authentication between the vehicle and the local service agent is achieved using the pre-shared password, and then the vehicle and the foreign service agent can establish a session key securely. BAN logic-based proof of the presented scheme is constructed to prove the correctness, and the security is proved by using the hybrid game model. At last, a comparison of performance between the proposed scheme and the existing similar schemes are provided based on implementation using OpenSSL, which shows that the performance of our proposed scheme is desirable and practical for VANETs environment. [ABSTRACT FROM AUTHOR]

Ni/Fe-Fe 3 O 4 nanocomposites were synthesized for dechlorination of 2,4-dichlorophenol (2,4-DCP). The effects of the Ni content in Ni/Fe-Fe 3 O 4 nanocomposites, solution pH, and common dissolved ions on the dechlorination efficiency were investigated, in addition to the reusability of the nanocomposites. The results showed that increasing content of Ni in Ni/Fe–Fe 3 O 4 nanocomposites, from 1 to 5 wt.%, greatly increased the dechlorination efficiency; the Ni/Fe–Fe 3 O 4 nanocomposites had much higher dechlorination efficiency than bare Ni/Fe nanoparticles. Ni content of 5 wt.% and initial pH below 6.0 was found to be the optimal conditions for the catalytic dechlorination of 2,4-DCP. Both 2,4-DCP and the intermediate product 2-chlorophenol (2-CP) were completely removed, and the concentration of the final product phenol was close to the theoretical phenol production from complete dechlorination of 20 mg/L of 2,4-DCP, after 3 hr reaction at initial pH value of 6.0, 3 g/L Ni/Fe-Fe 3 O 4 , 5 wt.% Ni content in the composite, and temperature of 22°C. 2,4-DCP dechlorination was enhanced by Cl − and inhibited by NO 3 − and SO 4 2 − . The nanocomposites were easily separated from the solution by an applied magnetic field. When the catalyst was reused, the removal efficiency of 2,4-DCP was almost 100% for the first seven uses, and gradually decreased to 75% in cycles 8–10. Therefore, the Ni/Fe–Fe 3 O 4 nanocomposites can be considered as a potentially effective tool for remediation of pollution by 2,4-DCP. [ABSTRACT FROM AUTHOR]

Bath wastewater is an ideal wastewater-reclamation source for its large discharge amount, simple pollutant composition and low pollutant content. The feasibility of reclaiming bath wastewater with a membrane bioreactor was investigated in a pilot plant of 10 m3 per day at an organic load of 0.50–1.85 kg-COD/(m3 per day). The operation was continued for 216 days without sludge discharge and chemical cleaning of membrane modules. The quality of the effluent obtained met the wastewater reclamation standard of China, with COD<40 mg/l, NH4+-N <0.5 mg/l and anionic surfactant (AS) <0.2 mg/l. Biological treatment removed most pollutants in the influent, degrading 34–85% of COD and 98% of anionic surfactant. The membrane separation balanced the unstable biological treatment of COD but demonstrated no contribution to anionic surfactant removal. Inorganic substances were found to accumulate in the bioreactor. The main reason for membrane fouling was considered to be sludge adhesion and gel layer formation over the outer membrane surface and microbial growth over the inner membrane surface. [Copyright &y& Elsevier]

Dairy farm manure and effluent are applied to cropland in China to provide a source of plant nutrients, but there are concerns over its effect on nitrogen (N) leaching loss and groundwater quality. To investigate the effects of land application of dairy manure and effluent on potential N leaching loss, two lysimeter trials were set up in clayey fluvo-aquic soil in a winter wheat-summer maize rotation cropping system on the North China Plain. The solid dairy manure trial included control without N fertilization (CK), inorganic N fertilizer (SNPK), and fresh (RAW) and composted (COM) dairy manure. The liquid dairy effluent trial consisted of control without N fertilization (CF), inorganic N fertilizer (ENPK), and fresh (FDE) and stored (SDE) dairy effluent. The N application rate was 225 kg N ha − 1 for inorganic N fertilizer, dairy manure, and effluent treatments in both seasons. Annual N leaching loss (ANLL) was highest in SNPK (53.02 and 16.21 kg N ha − 1 in 2013/2014 and 2014/2015, respectively), which were 1.65- and 2.04-fold that of COM, and 1.59- and 1.26-fold that of RAW. In the effluent trial (2014/2015), ANLL for ENPK and SDE (16.22 and 16.86 kg N ha − 1 , respectively) were significantly higher than CF and FDE (6.3 and 13.21 kg N ha − 1 , respectively). NO 3 − contributed the most (34–92%) to total N leaching loss among all treatments, followed by dissolved organic N (14–57%). COM showed the lowest N leaching loss due to a reduction in NO 3 − loss. Yield-scaled N leaching in COM (0.35 kg N Mg − 1 silage) was significantly ( P < 0.05) lower than that in the other fertilization treatments. Therefore, the use of composted dairy manure should be increased and that of inorganic fertilizer decreased to reduce N leaching loss while ensuring high crop yield in the North China Plain. [ABSTRACT FROM AUTHOR]

A textile and dyeing wastewater treatment plant is going to be upgraded due to the stringent discharge standards in Jiangsu province, China, and electron beam irradiation is considering to be used. In order to determine the suitable location of the electron accelerator in the process of wastewater treatment plant, the effects of electron beam (EB) irradiation on the biodegradability of various real wastewater samples collecting from the different stages of the wastewater treatment plant, the values of chemical oxygen demand (COD), biochemical oxygen demand (BOD 5 ), and the ratio of BOD 5 and COD (BOD 5 /COD), were compared before and after EB irradiation. During EB irradiation process, color indices and absorbance at 254 nm wavelength (UV 254 ) of wastewater were also determined. The results showed that EB irradiation pre-treatment cannot improve the biodegradability of raw textile and dyeing wastewater, which contains a large amount of biodegradable organic matters. In contrast, as to the final effluent of biological treatment process, EB irradiation can enhance the biodegradability to 224%. Therefore, the promising way is to apply EB irradiation as a post-treatment of the conventional biological process. [ABSTRACT FROM AUTHOR]