Microbial induced calcite precipitation (MICP) is one of the potential methods for improvement of engineering properties of soil. A laboratory study was conducted to investigate the influence of various factors on engineering properties of MICP-treated soil catalyzed by bacteria and ureases. Some of these factors include bacteria concentration, urease concentration, cementation media concentration, reaction time, type of sand, and curing conditions. The experiments of MICP catalyzed by Sporosarcina pasteurii and urease were conducted in similar conditions. The soil samples were prepared with full contact flexible molds (FCFMs). The results of unconfined compression test show that the experimental factors (bacteria/urease concentration, cementation media concentration, reaction time, and type of sand) have a significant impact on the MICP process and engineering properties of sand treated by both bacteria and urease, whereas the curing conditions has a small effect. The unconfined compression strength (approximately 1.76–2.04 MPa) of bacteria treated samples is almost $5\times$ (approximately 0.33–0.43 MPa) that of urease treated samples under similar urease activity. The MICP process catalyzed by bacteria is much more effective than the process catalyzed by urease in terms of engineering soil properties improvement.

Ozone is a typical hazardous pollutant in Earth’s lower atmosphere, but the phyllosphere and its microbiome are promising for air pollution remediation. Despite research to explore the efficiency and mechanism of ozone phylloremediation, the response and role of the phyllosphere microbiome remains untouched. In this study, we exposed Euonymus japonicus to different ozone levels and revealed microbial successions and roles of the phyllosphere microbiome during the exposure. The low-level exposure (156 ± 20 ppb) induced limited response compared to other environmental factors. Fungi failed to sustain the community richness and diversity, despite the stable ITS concentration, while bacteria witnessed an abundance loss. We subsequently elevated the exposure level to 5000~10,000 ppb, which considerably deteriorated the bacterial and fungal diversity. Our results identified extremely tolerant species, including bacterial genera (Curtobacterium, Marmoricola, and Microbacterium) and fungal genera (Cladosporium and Alternaria). Compositional differences suggested that most core fungal taxa were related to plant diseases and biocontrol, and ozone exposure might intensify such antagonism, thus possibly influencing plant health and ozone remediation. This assumption was further evidenced in the functional predictions via a pathogen predominance. This study shed light on microbial responses to ozone exposure in the phyllosphere and enlightened the augmentation of ozone phylloremediation through the microbial role.

Since the emergence of forward osmosis (FO), low energy requirements, low fouling propensity and high-water recovery have made it one of the most promising water purification technologies. However, there have been few reports focusing on the treatment of polymer flooding produced water (PFPW) using FO technology up to now. In the present work, porous FO membranes with/without palygorskite (Pal) nanoparticles were utilized as the separation membrane to evaluate the potential of a porous FO membrane in the treatment of oily wastewater containing HPAM and the effect of Pal nanoparticles on the FO performance was investigated. When the loading concentration of Pal in the membrane was 0.75 wt%, the water flux could reach 37.67 L m⁻² h⁻¹ by using 4 g L⁻¹ poly(sodium-p-styrenesulfonate) (PSS) as draw solution under a cross-flow rate of 18.5 cm s⁻¹, which was much higher than that for pure polysulfone (PS) membranes. Besides, the comparison between ultrafiltration (UF) and FO performance in treating HPAM solution indicated that FO possessed better antifouling capacity, since less decline and higher recovery of water flux were observed during the FO process. Furthermore, recycling the draw solution gave an almost unchanged water flux, which suggested the feasibility of draw solute regeneration in the FO process. This work broadens the application field of porous FO technology and may pave a new way in the treatment of PFPW.

The numerical source-apportionment model is an efficient and useful method for analyzing water-quality responses to nutrient loading in rivers and lakes. In this study, the Environmental Fluid Dynamic Code (EFDC) and numerical source-apportionment model were applied to Lake Bali in Jiujiang City, China to predict the contributions of various pollution sources to the lake at any time and position. We calibrated and validated the model by comparing its predictions with observed hydrodynamic and water-quality parameters from 2014 to 2015. Application of the calibrated model to simulate water-quality responses to a pollution source showed that the contribution of a pollution source to water quality in the lake has strong spatial heterogeneity. The results provide useful information for the optimization of pollution load reduction in Lake Bali and can be used to determine the most effective implementation of its pollution-control plan. The model built in this study can also be used for pollution source-apportionment in other urban lakes and is superior to other traditional source-apportionment models.

Orthogonal and single-factor experiments were used to investigate the remediation effect of single and mixed washing on arsenic-contaminated soil from a typical non-ferrous metal smelter. The optimal washing conditions, washing kinetics and speciation distribution of arsenic were determined. The obtained removal efficiencies of arsenic in the soil is 83.65%, which could be remedied to less than “ risk intervention values (As < 140 mg·kg⁻¹) for soil contamination of the development land” in soil environmental quality standard China (GB36600-2018) when the mixed ratio of Citric acid (1 mol·L⁻¹) & Rhamnolipid (1%) is 2:1, the ratio of liquid-solid is 15:1 and the washing time is 393 min. The repair effect of mixed washing was significantly higher than the single washing agents, and the washing kinetics was a heterogeneous diffusion process, which was consistent with Elovich model. In addition, mixed washing agents can effectively remove active and potential bioavailable arsenic from soil, which greatly reduces their bioavailability and environmental risk.