The goal of this study was to assess whether a large-scale commercial laundry contributes microplastics to the receiving wastewater treatment plant and to compare microplastic-like particle content in samples from three plants with varying industrial inputs and infiltration/inflow over 12 months. Suspected microplastic (MP) counts, morphology, and sizes were determined using a modified ASTM D8333-20 digestion method and fluorescence microscopy. Samples from a large commercial laundry were collected to determine the impact of laundering synthetic fabrics on MP content in wastewater influent. Influent and effluent samples were collected from each plant, and at one plant intermediate samples were collected before and after sand filtration to assess its role in MP abatement. Domestic wastewater heavily influenced MP-like particles in wastewater. Fibers released in laundering, domestic or commercial, constituted a minor part of overall particle counts. While fiber morphology in laundry wastewater accounted for up to 13% of total suspected MPs (4.7% average), it represented only 0.1–2.2% (0.8% average) of particles in influent at the two plants receiving industrial inputs and 0.2–1.7% (0.6% average) at the plant treating strictly domestic wastewater. On average, MP-like particle counts in commercial laundry water were four times lower than counts in wastewater influent. All three plants effectively removed MP-like particles, with average removals of 91.0, 95.4, and 97.1%. Most removal occurred after secondary treatment, presumably via enmeshment in residual solids, with sand filtration offering little additional benefit. The majority of particles were 10–50 μm, which may explain limited filtration capture. While effective, wastewater treatment plants remain major pathways for MP entry into the environment, and more research is needed to identify and address MP sources in wastewater.
Polyethersulfone (PES) membranes suffer from intrinsic hydrophobicity and severe fouling, limiting their applicability in dye-containing wastewater treatment. In this study, thin-film composite PES/GO/MXene nanofiltration (NF) membranes were fabricated through a vacuum-assisted nano-intercalation strategy that enables controlled assembly of GO and MXene nanosheets on PES substrates. Systematic tuning of the GO-to-MXene ratio revealed clear correlations between lamellar structure, surface chemistry and the resulting water permeability, dye rejection, and antifouling behavior. The optimized membrane (GO:MXene = 1:2) achieved a high pure water permeance of 50.1 L·m −2 ·h −1 ·bar −1 together with rejection rates of 97.3% for methylene blue and 93.8% for rhodamine B. Moreover, the membrane demonstrated stable dye rejection and a flux recovery ratio of ∼84% over five bovine serum albumin fouling-cleaning cycles, demonstrating good short-term operational stability. This work provides a promising interfacial engineering strategy to incorporate mixed 2D lamellar nanochannels into polymeric NF membranes for efficient purification of dye-contaminated wastewater.
Waste activated sludge (WAS) is a carbon-rich residual biomass that can be converted into a recycled carbon source for biological wastewater treatment; however, the applicability of low-temperature thermal-alkaline WAS lysate to coupled sulfate reduction and nitrate transformation remains unclear. This study optimized low-temperature thermal-alkaline pretreatment and evaluated the resulting lysate as the sole external carbon source in a continuous anaerobic reactor treating simulated sulfate- and nitrate-containing wastewater. The preferred pretreatment condition was pH 11, 90°C, 60 g total solids/L, and 120 min. Across the orthogonal experiments, acetate and propionate accounted for >75% of total volatile fatty acids (VFAs), while verification of the selected condition yielded ∼12,340 mg/L soluble chemical oxygen demand and 594 mg/L total VFAs. During continuous operation, the lysate established reducing conditions and supported sulfate and nitrate transformation. Under Stage II, when both the influent chemical oxygen demand/SO 4 2− ratio and temperature were increased, sulfate conversion and apparent nitrate conversion reached 81.9% and 71.5%, respectively, although their individual effects could not be resolved. Substantial net NH 4 + -N accumulation showed that nitrate disappearance did not represent complete nitrogen removal. 16S ribosomal RNA gene sequencing supported the proposed microbial associations, while ammonium accumulation remained a key concern for lysate reuse.
Microplastics (MPs) are widespread emerging pollutants in agricultural soils and frequently co-occur with pesticides. While numerous studies have addressed their combined effects, the impacts of biodegradable versus nonbiodegradable MPs and their particle sizes on pesticide behavior and ecotoxicity remain to be fully clarified. This study investigated the effects of biodegradable poly(butylene succinate) (PBS) and nonbiodegradable polypropylene (PP) MPs on the adsorption and dissipation of chlorantraniliprole (CHL) in soil and its combined toxic effects on Reticulitermes flaviceps . The results showed that the adsorption kinetics of CHL in soil and soil–MP systems fitted well with the pseudo-second-order model, and chemical adsorption dominated the process. PP MPs significantly increased the adsorption capacity of soil for CHL and reduced its dissipation rate, thereby prolonging the half-life of CHL in soil, with finer particles (1000-mesh) showing stronger effects than coarser ones (200-mesh). In contrast, PBS MPs exhibited weaker adsorption toward lipophilic CHL, which accelerated CHL degradation in soil. Toxicity bioassays showed that CHL alone significantly reduced the survival rate of R. flaviceps and induced oxidative stress and metabolic disorders. Coexposure with PP MPs further increased the activities of antioxidant enzymes superoxide dismutase and catalase, inhibited the activities of detoxification enzymes acid phosphatase and alkaline phosphatase, and aggravated the decline in termite survival. However, PBS MPs showed no obvious synergistic toxic effect. These findings demonstrated that MP type and particle size jointly control CHL soil adsorption capacity, degradation half-life, as well as acute lethal toxicity, oxidative stress, and detoxification metabolic disruption in the soil arthropod R. flaviceps . Nonbiodegradable PP MPs increase the persistence and bioaccumulation risk of CHL, while biodegradable PBS MPs pose a lower ecological risk and alleviate the combined toxic effects. This study provides scientific data for assessing the ecological risks of pesticide-MP combined pollution in agricultural soils.
The extensive application of herbicides in modern intensive agriculture has led to their persistent residue across multimedia environments, posing severe risks to ecosystem and human health. Among the current methods for removing herbicides, the single microbial remediation approach is often constrained by environmental fluctuations and the toxicity of high-concentration substrates, while the physical adsorption technology has the risks of desorption and secondary pollution. Modified biochar-assisted microorganisms are considered a useful method for efficient degradation of herbicides. This review provides an integrated overview of modified biochar-microbe synergistic remediation systems, covering four major herbicide classes: triazines, glycines, chloroacetanilides, and sulfonylureas. It explicitly proposes an “adsorption-biodegradation” coupling mechanism: modified biochar mitigates microbial toxicity by rapidly reducing herbicide bioavailability through adsorption, while simultaneously serving as a carrier and nutrient source to enhance the degradative activity. Furthermore, the study explores ecological functions such as the improvement of soil microenvironments, the regulation of microbial communities, and the promotion of functional gene expression, providing a theoretical foundation for the green in situ remediation.
