Search Results (5)

Brewery wastewater (BWW) often contains a high concentration of organic matter and nutrients, requiring pre-treatment before it can be effectively treated in conventional wastewater treatment plants. This study focuses on the use of coagulation–flocculation techniques to treat real industrial wastewater. Firstly, lab-scale tests have been carried out to determine the most effective coagulant and flocculant type and concentration. The levels of pollutants, including chemical oxygen demand (COD), biological oxygen demand in five days (BOD₅), total nitrogen (N_tot), total phosphorus (P_tot), and orthophosphate (P-PO₄³⁻) have been measured to assess the efficiency of the procedure. Industrial scale tests were performed in optimal conditions in order to evaluate the effectiveness of the treatment on a larger scale and estimate the generation of chemical sludge. The most effective substances for coagulation and flocculation were polyaluminium chloride (PAC) and anion-active flocculant (AAF) ZETAG 4139 0.1%, respectively, at concentrations of 675 mg·L⁻¹ and 40 mg·L⁻¹. During industrial-scale tests, the process allowed the effective removal of TSS (86.8%), N_tot (51.8%), P_tot (95.5%), and P-PO₄³⁻ (99.6%), while the limited removal of organic substances has been highlighted (BOD₅: 34.3%; COD: 26.5%). The dry matter (DM) content of the separated sludge was found to be 4.5–5%, and a yield of 1.01 kg_DM per kg of COD removed was obtained after flocculation treatment of the BWW. These findings can be beneficial for both the scientific community and technical operators, offering insights into the effectiveness of various coagulants and flocculants on industrial-scale wastewater treatment. Full article

The arsenic (As) pollution of water has been eliminated via intensive scientific efforts, with the purpose of giving safe drinking water to millions of people across the world. In this study, the adsorption of As(V) from a synthetic aqueous solution was verified using a Bentonite-Anthracite@Zetag (BT-An@Zetag) composite. The SEM, FT-IR, XRD, DSC, TGA, and SBET techniques were used to characterize the (BT-An@Zetag) composite. The adsorption of As(V) was explored using batch adsorption under varied operating scenarios. Five kinetic modelswere used to investigate kinetic data, whereas three isotherms had been used to fit empirical equilibrium data. According to the findings, the adsorption mechanism of As(V) was best described by the Freundlich isotherm with a maximum monolayer coverage of 38.6 mg/g showing pseudo-second-order mode. The estimated enthalpy (H°) indicates that the adsorption process is both chemical and endothermic.The calculated free energy (G°) indicates that the reaction is nonspontaneous. After four sequential adsorption cycles, the produced BT-An@Zetag composite demonstrated good reusability and a greater adsorption affinity for As(V) ions. Overall, the BT-An@Zetag composite is suited for removing arsenic from wastewater using adsorption as a cost-effective and efficient technique. Full article

Microalgae have a lot of potential as a source of several compounds of interest to various industries. However, developing a sustainable and efficient harvesting process on a large scale is still a major challenge. This is particularly a problem when the production of low-value products is intended. Chemical flocculation, followed by sedimentation, is seen as an alternative method to improve the energetic and economic balance of the harvesting step. In this study, inorganic (aluminum sulfate, ferric sulfate, ferric chloride) and organic (Zetag 8185, chitosan, Tanfloc SG) flocculants were tested to harvest Chlorella vulgaris in batch mode. Preliminary assays were conducted to determine the minimum dosages of each flocculant that generates primary flocs at different pH. Except for chitosan, the organic flocculants required small dosages to initiate floc formation. Additional studies were performed for the flocculants with a better performance in the preliminary assays. Zetag 8185 had the best results, reaching 98.8% and 97.9% efficiencies with dosages of 50 and 100 mg L⁻¹, respectively. Lastly, a 2⁴ full factorial design experiment was performed to determine the effects of the flocculant dosage, settling time, and mixing time on the Zetag 8185 harvesting efficiency. The harvesting efficiency of C. vulgaris was optimal at a dosage of 100 mg L⁻¹ and 3 min of rapid mixing. Full article

Reject water separated from digested sludge may be a potential source of nutrients due to its high content. However, most often, reject water after sludge dewatering is directed to sewage lines at wastewater treatment plants, negatively affecting their operation, especially in the biological part. The activities related to sludge conditioning before dewatering have a direct impact on the quality of the reject water. The reject water of raw digested sludge is characterized by very high concentrations of ammonium nitrogen, at 1718 mgN-NH₄⁺/dm³; phosphates, at 122.4 mgPO₄³⁻/dm³; and chemical oxygen demand (COD), at 2240 mgO₂/dm³. The objective of the research was to determine the impact of selected sludge conditioning methods on the quality of reject water obtained after sludge dewatering. The following parameters were analyzed in the reject water: the chemical oxygen demand (COD), phosphates, ammonium nitrogen, and total suspended solids (TSS). It has been observed that the sludge sonification process increases the content of impurities (COD, phosphates) in reject water with an increase in the amplitude of the ultrasonic field. On the other hand, the chemical reagents cause a decrease in the concentration of the pollutants with an increase of the chemical dose. It has been found that the inorganic coagulant PIX 113 gives much better results regarding the reduction of contamination than the polyelectrolyte Zetag 8180. Full article

The paper presents the impact of different methods of sewage sludge conditioning on the improvement of sludge dewatering during pressure filtration processes. The following conditioning methods were tested for sludge preparation: sonication, addition of organic and inorganic chemicals (Zetag 8180, PIX 113 and the combined action of both substances). The research covered: physical and chemical analysis of sewage sludge, measurement of capillary suction time as an indicator of sludge dewaterability, some technical parameters of sludge pressure filtration process and the analysis of filtrate to assess the degree of contamination. The results of the research showed that the final water content of the prepared sludge decreased, while the specific filtration resistance increased. Among the tested methods the best results of sludge dewatering effects were obtained for sonicated sludge and its preparation with inorganic coagulant PIX 113. The combined effect of sonication with the addition of chemicals Zetag 8180 and PIX113 to sludge allowed for the reduction of organic substances, ammonium nitrogen and phosphates in filtrate after sludge dewatering. Full article