This study tried to use electroflocculating precipitated waste to prepare a Si@Al adsorbent by simply mixing sodium silicate at a mass ratio of 4:1 and calcining at 200 °C for 2 h. The adsorbent was low cost, high efficiency, and could remove a variety of contaminants (organic pollutants, antibiotics, and metal ions) from water. In this study, adsorbent characterization and pollutant adsorption experiments were carried out. The results showed that: Si@Al adsorbent had uniform particles, distinct layers, a loose porous appearance, and the internal structure was scattered without a crystal structure. The optimal adsorption conditions for tetracycline were as follows: dosage of adsorbent 2.0 g/L, reaction time 10 min, pH = 4.5, and tetracycline removal rate of 97.13%. The optimal adsorption conditions for MB (MB stands for methylene blue) were an adsorption dosage of 4.0 g/L, a reaction time of 15 min, pH = 4.5–8.5, and a removal rate of 96.39%. The optimal adsorption conditions for Cu were a 2.0 g/L dosage of adsorbent, a reaction time of 30 min, a pH of 8.5, and a highest removal rate of 97.47%. It was worth noting that the effect of temperature on TC, MB and Cu was not significant. At the same time, the kinetic fitting results showed that the adsorption of MB was more consistent with the quasi-second-order kinetic model, with R² ranging from 0.9788 to 1.0000. The adsorption of TC and Cu was more consistent with the quasi-first-order kinetic model, with R² ranging from 0.9598 to 0.9999 and 0.9844 to 0.9988, respectively. According to the results of thermodynamics, kinetics and zero potential point, the adsorption of tetracycline and methylene blue was mainly a physical adsorption, multilayer heterogeneous or single-layer homogeneous adsorption process. The adsorption of Cu was categorized as multi-layer heterogeneous chemical adsorption. The co-existing substances had little effect on the properties of the adsorbent, and the adsorbent could be recycled 5 times. Compared with other adsorbents, the results showed that the adsorbents had obvious advantages in terms of the raw material source, preparation method, time cost and removal effect. This study provided a “waste into treasure, green and efficient” multi-pollutant adsorption method.

The problem of the foul odor caused by H₂S in livestock farms has become a major complaints. In this study, optimal sulfur-oxidizing bacteria (SOB) strains were screened from dairy farm wastewater and the adjacent soil for odor treatment. The strains and physiological functions were determined by identification and genome comparison, and the optimal operating conditions were determined by experiments under different conditions. The identification results showed that the strain that had the highest homology with Halomonas mongoliensis was Halomonas sp. AEB2. The comparative genomic results showed that the average nucleotide identity and DNA–DNA hybridization value were 95.8% and 68.6%, respectively. The optimization results were as follows: sodium succinate-carbon (10 g/L) and ammonium chloride-nitrogen (0.07 g/L). The optimal operating conditions were as follows: seeding rate 4%, temperature 30 °C, stirring speed 90 rpm, and pH 8. The oxidation products of AEB2 were mainly elemental sulfur and tetrathionate, and the metabolic pathway of AEB2 was constructed accordingly. This study suggests a feasible path to reduce H₂S emissions from dairy farms, and it provides theoretical support for the restoration of livestock environment and sustainability.