Activated carbon has widespread application in antibiotic-loaded wastewater treatment in recent years, owing to its developed pore structure, high superficies reactivity, and excellent mechanical and chemical stability. In this work, sorption experiments of four representative antibiotics, including sulfadiazine (SDZ), norfloxacin (NOR), metronidazole (MDE), and tetracycline (TC), over granular activated carbon (GAC), which was made from maize straw, were firstly studied. Kinetics, mechanism, and isotherm models related to the sorption process were employed. Results revealed that the sorption capacity by GAC followed the order SDZ > NOR > MDE > TC. The sorption kinetics of the four antibiotics well conformed to the pseudo-second-order model. Both the Weber-Morris intraparticle diffusion and Boyd kinetic models conveyed the information that film diffusion was dominant in the sorption process. The sorption isotherm was better fitted to the Langmuir model. This research may pave a basic way for removing antibiotics in municipal and industrial wastewater by activated carbon.

Microbiological activities are essential in the bioremediation of polluted soils. The enzymatic activities of microorganisms are usually used as a biological indicator of soil health. The aim of this work was to observe the catalase, acid phosphatase (AcP), and alkaline phosphatase (AlP) activities in soil that was amended with agro-industrial by-products and macronutrients during the process of total petroleum hydrocarbon (TPH) removal. To this end, microcosm tests were performed with soil and agro-industrial by-products ratios of 100:2:2, for soil:sugarcane bagasse pith:filter cake mud (SSF); 100:2, for both soil:sugarcane bagasse pith (SS); and for soil filter cake mud (SF). The macronutrients—carbon, nitrogen, and phosphorus—in the experimental treatments were adjusted to 100:10:1 with a solution of NH₄NO₃ and K₂HPO₄. The best TPH removal (51.4%) was obtained with SSF at 15 days. In addition, a significant correlation was observed between TPH removal and AlP as well as AcP (r = 0.74, p < 0.0001; r = 0.70, p < 0.0107, respectively). Fungi growth was also correlated with both AlP (r = 0.97, p < 0.0001) and AcP (r = 0.95, p < 0.0001) activities. Besides, bacterial and fungi growth showed a correlation with TPH (r = 0.86, p < 0.001; r = 0.77, p < 0.0034, respectively). It could be said that the agro-industrial by-products and macronutrients contributed to pollutant removal from the oil-polluted soil at relatively short amount of time. In addition, the enzymatic activities were increased after the treatment; in this study, the high sensitivity enzyme was AlP, and it could be used as an indirect indicator of oil pollutant removal.

Efficacy of an in situ algaecide treatment can be predicted prior to an application by physically modeling exposures and responses with laboratory experiments. A sodium carbonate peroxyhydrate (SCP) algaecide was used in a drinking water reservoir (Hartwell Lake, Anderson, SC) to control a benthic algal assemblage putatively producing 2-methylisoboreol (MIB) and geosmin, compounds with adverse taste and odor attributes. These SCP applications provided an opportunity to test hypotheses regarding potential convergence of laboratory and in situ exposures and responses. Objectives of this study were to (1) measure responses of a benthic algal assemblage from Hartwell Lake to 7-day laboratory exposures of SCP [measured as hydrogen peroxide (H₂O₂) concentrations], (2) to measure the exposure of SCP (as H₂O₂) applied in a cove of Hartwell Lake and consequent responses of the algal assemblage, and (3) compare exposures and responses measured in the laboratory and in situ. Results demonstrated that in laboratory exposures, H₂O₂ released by SCP dissipated within 48 h. Significant responses of the algal assemblage in terms of phycocyanin concentrations and cell densities were measured 4 days after treatment (4-DAT) and 7-DAT following exposures of 453, 615, and 812 mg H₂O₂ m⁻². The H₂O₂ exposure measured in situ was comparable to effective laboratory exposures in terms of initial exposure (619 ± 428 mg H₂O₂ m⁻²) and exposure duration (dissipation within 30 h), but the in situ exposure had a large deviation initially (i.e., ±428 mg H₂O₂ m⁻²) and was an order of magnitude less than the targeted initial exposure. Therefore, comparison of measured responses was critical to infer comparable exposures and confirm accuracy of the laboratory model. Significant in situ responses were measured 4-DAT and 7-DAT in terms of phycocyanin concentrations and cell densities, and were comparable to responses obtained from effective laboratory exposures (i.e., 453, 615, and 812 mg H₂O₂ m⁻²). Decreases in measured concentrations of MIB and geosmin at the intake of the drinking water treatment facility provided additional evidence that algae were sufficiently exposed to H₂O₂ from SCP. Results of this experiment provide evidence for the design and use of physical laboratory models to predict responses of algae in the field.

Dynamics of chemical characteristics and hygienic quality, particularly nutrients, heavy metals, and bacterial pathogens, were investigated along the storage of anaerobically digested slurry derived from chicken and pig manure. The average total solid (TS) content decreased by 3.6 and 24.1%, while soluble chemical oxygen demand (SCOD) decreased by 23.7 and 31.4%, in chicken manure- and pig manure-digested slurries storage, respectively. A rapid increase in NH₄ ⁺-N concentration from 1600 to 4800 mg/L in chicken manure-digested slurry and from 1200 to 1700 mg/L in pig manure-digested slurry was noted, particularly during the first 10 days of storage. A positive correlation between TS and content of heavy metals (Cu, Zn, Cr, and Pb) in the digested slurry was clearly shown. These metals are mainly associated with suspended particles and tend to be settled in the bottom during the storage process. Increasing attention should be paid to the land application of these bottom-settled digestates with higher TS content. The number of total coliforms and Escherichia coli in the both digested slurries decreased continuously during the whole storage period. The higher reduction rate observed during the storage of chicken manure-digested slurry may be due to the higher content of NH₄ ⁺-N, which may cause the inhibition of gram-negative bacteria. The results of this study provides a better understanding of the storage process of anaerobically digested slurry, which could benefit the digested slurry further utilization as agriculture fertilizer.

Several studies have demonstrated that the most effective way to control eutrophication is to reduce phosphorus input at the scale. Water quality monitoring programs need to separately evaluate the different polluting sources to provide a suitable estimate of their relative contributions and thus accurately prioritize possible restoration actions. Urban area cases, where a portion of untreated wastewater is often discharged directly into receiving surface waters by combined sewer overflows (CSOs) during rain events, remain unsolved. In this context, an urban watershed located in Northern Italy with 60 CSOs has been chosen as a case study, and four rainy events have been hourly monitored. The proposed monitoring program consists of the combined use of caffeine and turbidity to estimate the volume and phosphorus load spilled into the river from the CSOs, respectively. Caffeine proved to be a suitable molecule to quantify the volume of wastewater discharged into water bodies, based on a per capita caffeine load of 10.8 mg inhab⁻¹ d⁻¹, estimated in the present work. This research showed that, on average, more than half of the total phosphorus loads transported by the river is due to the CSO discharges (56.5%). The knowledge of the prevailing responsibility of the CSO discharges for the Lambro River quality allows prioritizing effective restoration actions.

Present study investigates the coagulation ability of Plantago ovata (P. ovata) seed extracts for turbidity removal. The active coagulant agents were successfully extracted from P. ovata seeds using different solvents such as distilled water (PO-DW), tap water (PO-TW), NaCl (PO-NaCl), and ammonium acetate (PO-AA). Experiments were conducted in batch mode for initial turbidity such as 500 NTU (high), 150 NTU (medium), and 50 NTU (low). Results demonstrated that P. ovata extracts are less efficient in low turbidities, while PO-NaCl was found to provide high coagulation activity in all initial turbidity concentrations compared to other extracts. PO-NaCl was able to remove 98.2, 94.9, and 80.2% of turbidity from water having in initial turbidities of 500, 150, and 50 NTU, respectively. Coagulation activity of the extract was the best when the extraction was performed for 50 min at room temperature. Jar test procedure with the coagulation time of 1 min and flocculation time of 30 min was optimized, irrespective of the initial turbidity. The optimum settling time for 500, 150, and 50 NTU water samples were 20, 30, and 90 min, respectively. PO-NaCl was used in different pH turbid solutions and it was found to be working very efficiently in alkaline conditions. The coagulation efficiency of the coagulant stored in refrigerator was higher than that stored at room temperature. Thus, the natural coagulants extracted from P. ovata seeds revealed to be effective for turbidity removal.

This study investigated the use of ceramic membranes to remove total suspended solids (TSS), organics (expressed by chemical oxygen demand, COD), and bisphenol A (BPA) via microfiltration (MF, pore size 0.45 μm) and ultrafiltration (UF, cutoff 150 kDa) in post-treatment of effluents from aerobic granular sludge reactors (GSBRs). The efficiency of removal of COD, BPA, and TSS in MF was similar to that in UF; however, it was achieved at a lower pressure, which reduces energy consumption during the filtration process. Despite the similar quality of the permeates in MF and UF, the permeate flux averaged almost 20% higher in UF than in MF. The rejection coefficients were 77–82% for COD and 48–100% for BPA. In both MF and UF, TSS were totally removed. In the integrated system of aerobic granular sludge reactor and membrane installation, total removal of COD was 92–95% and that of BPA was above 98%, independently of the membrane technique. The high efficiency of BPA removal in MF and UF, despite pore sizes in the MF and UF membranes larger than the BPA molecules, suggests that some part of the BPA was first bound by particulate organic matter in the biologically treated wastewater before this sorbed form was removed by the membranes. Furthermore, the high removal of COD and BPA, even in MF, was attributed to adsorption on the membranes, in addition to sieve retention.

Natural zeolite clinoptilolite and synthetic zeolite Na-A were characterized using XRD and SEM to be used as adsorbents for ammonia from aqueous solutions, ground water, and sewage water. Clinoptilolite was mechanically activated for 2, 4, 6, and 8 h to study the effect of activation in enhancing the adsorption capacity. The adsorption by activated natural zeolite and synthetic zeolite is high pH dependent and achieve the best values at pH = 7. The adsorption capacity of activated natural zeolite increases with increasing the activation from 2 to 8 h achieving removal percentage close to that obtained using synthetic zeolite. The equilibrium was obtained after 60 min for synthetic zeolite and all the activated natural zeolite (except 2-h-activated product, the equilibrium was achieved after 30 min). The kinetic studies reflected the high fitness of the adsorption results of activated natural zeolite products and synthetic zeolite with pseudo-second-order model rather than the other kinetic models. The obtained isotherms reflected the formation of S-type isotherm curve for the adsorption using mechanically activated clinoptilolite and L-type curve for the uptake using synthetic zeolite. The results represented well with Langmuir model followed by Temkin and Freundlich model for adsorption using synthetic zeolite. The uptake using mechanically activated clinoptilolite can be represented by Temkin model rather than both Langmuir and Freundlich models. Thermodynamic parameters indicate spontaneous endothermic adsorption of ammonia using all the zeolitic products under investigation. Finally, the mechanically activated natural zeolite and synthetic zeolite exhibit high efficiency in the removal of ammonia and other water pollutants from ground water and sewage water.

Chemical inputs from agricultural activities represent a threat to aquatic biota and its biochemical systems. Among these systems, acid phosphatases are involved in autophagic digestive processes, decomposing organic phosphates, signaling pathways, and other metabolic routes. In vitro tests are helpful to generate hypotheses about pollutant mechanisms of action through comparison of the toxicity effects of these compounds. In this work, we investigated the inhibitory effects of four organic pesticides and three metals on the acid phosphatases extracted from the freshwater microcrustacean Daphnia similis and the fish Metynnis argenteus. Our results demonstrated that only the metals have considerable inhibitory effects (50% or higher) on the enzyme activities. The calculated median effect concentrations (IC50) for the enzyme inhibition were 0.139 mM Hg²⁺ (fish enzyme), 0.652 mM Cu²⁺ (fish enzyme), and 1.974 mM Al³⁺ (Daphnia enzyme). Due to the relatively low value of the inhibition parameter for Hg²⁺, its inhibitory property could be used as a tool for Hg²⁺ detection in environmental samples. The enzyme activities obtained in the presence of the inhibitors are potential data as in vivo biomarkers for metals in both aquatic species.