Search Results (91)

The treatment of oily wastewater represents a significant environmental challenge, requiring efficient separation technologies and waste valorization. This study evaluated different types of coagulants (ferric chloride 38% m/m, aluminum polychloride 18% m/m, aluminum sulfate 8% m/m, and ferrous sulfate 6% m/m) and anionic polymers (from six suppliers) for treating poultry slaughterhouse effluent, aiming to optimize both clarification and oil recovery from the floated sludge. Bench-scale jar tests (G = 300 s⁻¹ and 30 s⁻¹) were followed by full-scale validation in a dissolved air flotation unit (100 m³ h⁻¹) at a poultry processing WWTP. Recovered oil was extracted by hot cooking (95 °C) and tridecanter centrifugation, and its quality (moisture, acidity, saponification index) was assessed. A techno-economic analysis, including simple/discounted payback, NPV, IRR, Monte Carlo simulation (10,000 iterations, Python), and deterministic sensitivity analysis, was performed. Ferric chloride (38% m/m) produced the best technical results: treated effluent turbidity < 30 NTU, oil yield of 360 L day⁻¹ with moisture < 2% at the tridecanter outlet, and consistent sludge dewaterability (moisture 55–65%). Oil moisture increased dramatically (to >30%) after storage due to condensate contamination from an inefficient exhaust system, a critical operational flaw that must be corrected. No statistically significant effect of polymer type on oil recovery was observed, although high variability (CV > 50%) was noted during PAC tests. The simple payback period for ferric chloride was 60.7 months (discounted: 64.1 months), with a positive median NPV (USD 7925) under a 12% p.a. discount rate. Sensitivity analysis showed that the investment is most sensitive to oil price: a 20% drop in oil price leads to a negative NPV (−USD 21,727). Despite this risk, the project provides environmental compliance and waste-to-value benefits. The study demonstrates that ferric chloride enables effective oil extraction from poultry wastewater, but proper exhaust design is essential to maintain oil quality. Future work should focus on standardized test durations (≥72 h) and automated monitoring to reduce variability. Full article

Poultry farming is important from a food point of view, as it provides products for the population. Waste resulting from poultry farming and processing is environmentally sensitive, which is why treatment technologies are crucial for sustainability. Conventional pre-treated wastewater originating from the poultry sector, combined with innovative methods of using substances with antimicrobial effects constitute another approach to eliminating health risks. This research aimed to evaluate the behavior of bacterial strains isolated from water samples treated by reverse osmosis (RO), ultrafiltration (UF), and ultraviolet disinfection (UV). To choose our antimicrobial substances, we surveyed the population using the Google Forms platform and the official questionnaire. Using a factorial design, the concentration of antibiotic or antiseptic, as well as the duration of their action on bacterial strains isolated in pure culture, was varied. The optical densities of bacterial cultures reflect the efficiency of treatments with antibacterial or antiseptic substances. Factorial design, corroborating the experimental results, led to the following: 4.84 mg·L⁻¹ antibiotic for 7.6 h and 4.23 mg·L⁻¹ chloramine for 16.23 h. The results obtained from mathematical modeling correspond to a decrease in the bacterial population. In perspective, combining purification technologies with antimicrobial substances, adapted to the volume of water through mathematical modeling, will reduce the risk of microbiological contamination, with bacterial recovery rate values ranging between 0.58 and 1.21 in the case of antiseptic using, and between 0.60 and 0.92 in the case of antibiotic using. Full article

Background: This study aimed to assess the presence of thermotolerant Campylobacter resistant to ciprofloxacin and erythromycin in poultry slaughterhouses and retail markets, as well as to characterize their multidrug resistance profiles, genetic determinants, and clonal relationships. Methods: Samples were collected at slaughterhouses from cecal content (n = 270), neck skin (n = 270), and wastewater (n = 9), and at retail markets from breast skin (n = 241). Isolates were obtained from mCCDA agar supplemented with ciprofloxacin (2 μg/mL) and identified as C. jejuni or C. coli by PCR. The agar microdilution test was used to determine the minimum inhibitory concentration for ciprofloxacin and erythromycin, and other critical antibiotics. Point mutations in gyrA (Thr86Ile) and 23S rRNA (A2075G), virulence genes (flaA, flhA, cadF, and cdt), and clonal relationships were assessed by PCR and PFGE. Results: At the slaughterhouses, thermotolerant Campylobacter spp. resistant to erythromycin and ciprofloxacin were detected in 48.55% (107/549) of the samples, whereas 4.56% (11/241) of retail samples were positive. The Thr86Ile substitution in gyrA and the A2075G mutation in the 23S rRNA gene were detected in 92.97% and 89.84% of the isolates, respectively. Most isolates (>80%) were multidrug resistant and harbored key virulence genes (flaA, flhA, and cadF). C. jejuni exhibited the highest prevalence of cdt genes (76.19%). There was substantial genotypic diversity among isolates, with broad distribution across the sampled matrices and sites. Conclusions: These findings highlight the circulation of multidrug-resistant and potentially virulent thermotolerant Campylobacter spp. in the later stages of the poultry meat supply chain. Full article

The meat industry generates wastewater with high organic matter loads, posing a significant environmental risk if not properly treated. The present study evaluated the performance of a horizontal subsurface flow constructed wetland (HSSF-CW) treating slaughterhouse effluents characterized by high-strength influent concentrations of 3570.51 ± 153.82 mg/L COD, 2114.33 ± 104.58 mg/L BOD₅, and 1173.77 ± 96.95 mg/L TOC. Furthermore, Response Surface Methodology (RSM) was employed to model and optimize the operational parameters. The independent variables considered were hydraulic retention time (HRT: 3, 5, and 10 days) and vegetation type (Heliconia latispatha, Typha latifolia, and polyculture). The results demonstrated a statistically significant improvement in treatment efficiency, achieving maximum removal efficiencies of 86.5% for COD, 89.4% for BOD₅, and 91.5% for TOC. The statistical models exhibited high accuracy (R² ≥ 0.996, p < 0.001). Adjusted response surface equations identified the polyculture with a 5-day HRT as the most favorable operational scenario. These findings confirm that properly designed and operated constructed wetlands represent a viable and sustainable alternative for treating high-load agro-industrial effluents, contributing to the protection of receiving water bodies. Future research should focus on full-scale studies and the inclusion of critical parameters such as nutrients and pathogens for a more comprehensive system characterization. Full article

Microbial fuel cell (MFC) technology represents a promising bioelectrochemical approach for the simultaneous generation of electricity and treatment of high-strength wastewater. However, the performance of MFCs strongly depends on the metabolic potential and synergistic interactions of the inoculated microbial community. This study evaluated the electrochemical activity and COD removal efficiency of three individual bacterial strains, Lysinibacillus sphericus A1, Bacillus cereus A2 and Lactococcus lactis A4, compared with a developed consortium under long-term operation using poultry slaughterhouse wastewater as a substrate. All inocula were tested in dual-chamber MFCs for 30 days, and performance indicators included power output, voltage, and removal of chemical oxygen demand (COD). The consortium showed the highest power of 170 mW/m² and the optimal voltage–current ratio at a current of 900 mA/m² and 245 mV under decreasing external resistance from 1000 to 50 Ω. The highest COD removal (84.4%) was also recorded, surpassing all pure cultures and demonstrating a significant improvement compared with B. cereus A2 and L. lactis A4. Meanwhile, the lowest power of 52 mA/m² was recorded during testing of L. lactis A4, at 650 mA/m² and 120 mV. Compared with single cultures, the consortium produced approximately 15% higher power density than L. sphericus A1, about 29% higher than B. cereus A2, and more than threefold higher than L. lactis A4. This study highlights the potential of a consortium as an efficient biocatalyst for MFC-mediated wastewater treatment and suggests that selecting complementary strains with diverse metabolic functions can substantially improve system performance. Full article

In recent years, concerns about sustainability in livestock farming have been raised. The livestock sector is accused of substantial greenhouse gas emissions, environmental pollution (i.e., wastewater with high COD and rich in N and P that can pollute freshwater and cause eutrophication), and resource consumption. The use of fossil resources to produce synthetic fertilizers is the major source of pollution indirectly attributable to livestock farming. However, the polluting load of the livestock sector can be used to produce energy and materials, increasing its sustainability. The scope of this work was to critically review the methods of management and valorization of waste from the livestock sector (slurry, manure, abattoir wastewater, slaughterhouse waste, and aquaculture waste). The various technologies for energy valorization (i.e., bio-H₂ and bio-CH₄) will be represented. The perspectives and challenges for the exploitation of these wastes to produce high-added-value molecules, extraction of bioactive molecules, alternative proteins, biofertilizers, and biopolymers will also be discussed in view of enhancing sustainability. Examples of possible large animal waste-based integrated biorefineries have also been proposed. Full article

This bibliometric study evaluates scientific production between 2015 and 2025 inclusive on anaerobic digestion of pig slurry and slaughterhouse wastewater for biomethane generation. A total of 1.414 documents were identified for pig slurry and 250 for slaughterhouse wastewater, reflecting a marked imbalance in research attention. For pig slurry, the literature shows strong consolidation, with consistent focus on biogas yield optimization, emission mitigation, and agricultural valorization of digestate. By contrast, slaughterhouse wastewater research is comparatively limited, fragmented across technical case studies, and often concerned with process inhibition, pretreatment strategies, and integrated treatment systems. Despite this disparity, both residues are recognized as important feedstocks for renewable energy recovery, with co-digestion offering particular promise in terms of process stability and biomethane enhancement. Full article

Poultry slaughterhouse wastewater (PSW) affects environmental and economic issues, and the introduction of modern treatment technologies, including microalgae-based ones, is strictly necessary. In this study, bioremediation of unsterilized PSW by several algal representatives of the genera Chlorella, Tetradesmus, Desmodesmus, and Neochloris was investigated. All microalgae grew in original wastewater, and the elevated N, P, and S levels in PSW allowed the microalgae to increase the biomass yield (from 2.44–3.15 to 2.73–4.42 g L⁻¹). Modification of PSW for cultivation of microalgae made it possible to obtain biomass with a high content of valuable metabolites. The highest protein content was observed in cells of cultures of Chlorella sorokiniana and Neochloris sp. (26% and 33% of the final dry weight, respectively). At the same time, starch and lipids were also accumulated in the algal cells at substantial levels in both original and modified PSW. With the growth of algae, a decrease in the relative abundance of members of Arcobacteraceae and Clostridium, which include pathogens, was also observed. At the same time, PSW contained a variety of bacteria capable of stimulating the growth of microalgae. Thus, integrating microalgae into the treatment of PSW will reduce the negative impact of such wastewaters on the environment and improve the sanitary indicators. Full article

Slaughterhouses generate a huge amount of highly polluted wastewater; if left untreated, this effluent could seriously threaten the environment and human health. In the present study, Ag₂O/Ba/TiO₂ nanocomposite was synthesized using the precipitation method, and its efficacy was investigated for the remediation of real slaughterhouse wastewater (SWW) under visible light. Its performance was assessed for the inactivation of bacterial strains identified in SWW and for the degradation of total organic solids, volatile solids, fixed solids, and heavy metals. The results indicated an excellent photocatalytic performance of the synthesized Ag₂O/Ba/TiO₂ nanocomposites, confirmed by 87.3% volatile solids, 30% total organic solids, and 40% fixed solids removal from SWW. The zone of inhibition runs from 4 to 9 mm, and the nanocomposites have demonstrated outstanding bacterial inactivation activity in this range. It has been shown that the synthetic Ag₂O/Ba/TiO₂ nanocomposites can function as an effective photocatalyst for the remediation of SWW and other waste products produced by various industries worldwide. Full article

Three wastewater sources, namely slaughterhouse wastewater, cheese whey, and wine lees, were used for volatile fatty acid (VFA) production with the aim of reducing polluted wastewater discharge to the water bodies and creating a useful product. Cheese whey and wine lees were proved to be good substrates to produce VFAs, obtaining maximum bioconversion percentages in g COD-VFA/g TCOD initial of 90% and 72% for cheese whey and wine lees, respectively. The composition of the VFAs produced from each wastewater stream varied, with acetic, propionic, isobutyric, and isovaleric acids being the most dominant. These VFAs were used as an environmentally friendly fungicide against Fusarium culmorum, resulting in a reduction of the radial mycelial growth of Fusarium culmorum for all the effluents tested. A thermal pretreatment of the VFAs resulted in an improved antifungal efficiency if compared to the untreated VFAs or a UV pretreatment. Full article

In the process of biogas production, various types of substrates with suitable energy potential are utilized to generate biogas in plants designed for cogeneration (CHP) of electricity and heat. This paper presents a literature review focused on different substrates involved in biogas production, emphasizing their optimization potential. Data for this research were gathered through a comprehensive review of scientific and scholarly literature from global databases. The study examines the biogas production capabilities of various feedstocks employed in cogeneration plants, highlighting the energy potential of substrates, including livestock byproducts such as liquid and solid manure, energy crops, organic waste from the food and slaughterhouse industries, as well as municipal wastewater and solid organic waste. Furthermore, we conducted a practical case study in the municipality of Čačak, which provides valuable insights into effective practices and strategies that can be broadly applied to enhance biogas production in similar contexts. The findings reveal significant variations in biogas production potential among different substrates, emphasizing the importance of strategic selection and management practices. This study contributes to the field by providing a clearer understanding of the substrate optimization process and practical insights that can inform the development of more effective biogas production strategies in local municipalities. Full article

Background: Laying hens, which are widely utilized for consumption and export in various regions, experience prolonged antibiotic exposure due to their longer lifespan, increasing the risk of antibiotic resistance and impacting the microbial environment of poultry slaughterhouses. Given the significance of extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli in food safety, this study aimed to investigate the prevalence of ESBL genes in E. coli isolated from a laying hen slaughterhouse in Konya, Turkey. Methods: Sampling was conducted using a convenient sampling approach, and a total of 150 samples were collected from a single slaughterhouse over six visits during both warm (June–August) and cold (January–March) seasons to evaluate seasonal variations. Samples were categorized into environmental sources (personnel, air, wastewater, eggs) and carcass-related sources (cloaca, carcasses at critical control points, final product). Classical cultural and molecular techniques and antimicrobial susceptibility tests were used for ESBL presence and gene characterization. For sequence analysis, the bidirectional Sanger Gene sequence analysis method was applied. Results: PCR-based detection identified 10 of the 17 isolates as E. coli by amplifying the uspA gene, and bidirectional Sanger sequencing further confirmed these isolates at the species level. The E. coli isolates were detected at various sampling areas, including personnel, carcasses after evisceration, and raw wastewater samples collected at different time points. In the multiplex PCR analysis, most ESBL isolates were positive for the blaCTX-M gene. The co-existence of blaTEM and blaCTX-M genes was detected in five samples. Additionally, three genes (blaSHV, blaCTX-M, and blaOXA) were identified in a carcass sample after evisceration. All ESBL-producing isolates harbored the blaCTX-M1 gene, and multiple antibiotic resistance was observed across all isolates. The presence of these genes was strongly associated with resistance to ampicillin, amoxicillin-clavulanic acid, aztreonam, cefepime, cefpodoxime, cefuroxime, and cephalothin, highlighting the critical role of blaCTX-M in driving the multidrug resistance patterns observed in this study. The highest resistance rate (80%) was observed in “personnel” and “carcass samples after evisceration”, while all isolates remained sensitive to carbapenems (imipenem and meropenem). Conclusions: Our findings highlight the importance of the laying hen slaughter line as a potential source of contamination with ESBL-producing E. coli, which poses significant implications for food safety and public health. These findings underscore the need for improved control measures to mitigate ESBL E. coli transmission in poultry processing and highlight the importance of optimizing antibiotic use strategies in laying hen farming. Full article

This study investigates the bioremediation potential of Marinobacter-hydrocarbonoclasticus SDK644, a strain that has been isolated from petroleum-contaminated environments, for the degradation of the herbicide metribuzin and the treatment of slaughterhouse effluent. The strain’s bacterial growth and degradation capacity were assessed under varying conditions, including different metribuzin concentrations, pH values, temperatures, and inoculum sizes. The strain demonstrated optimal growth at a metribuzin concentration of 20 mg/L, with an optical density (OD600) of 0.408 after 96 h. At this concentration, 80% of the chemical oxygen demand (COD) was reduced over 144 h. The optimal growth conditions for M. hydrocarbonoclasticus SDK644 were identified as a pH of 7 and a temperature of 30 °C, where the enzymatic activity and degradation efficiency were maximized. Additionally, the treatment of slaughterhouse effluent showed significant reductions in organic pollution, with the COD and biochemical oxygen demand (BOD₅) decreasing by 80% (from 1900 mg/L to 384 mg/L) and 81% (from 1700 mg/L to 320 mg/L), respectively, within seven days. The strain also facilitated ammonium removal and promoted nitrification, indicating its suitability for treating high-organic-load wastewater. Notably, the visual transformation of the effluent, from a dark red color to a clear state, further highlighted the efficiency of the treatment process. This research highlights the adaptability of M. hydrocarbonoclasticus SDK644 to a wide range of environmental conditions and its efficiency in biodegrading metribuzin and treating complex wastewater. The findings demonstrate the strain’s potential as a sustainable solution for mitigating organic pollution in agricultural runoff, pesticide-contaminated water, and industrial effluents. Full article

The anaerobic co-digestion (ACoD) of sludge (S) and slaughterhouse wastewater (SW) can improve biomethane production and removal efficiency in terms of organic matter. The aim of this study was to determine the impact of temperature on co-digestion, considering different hydraulic retention times (HRTs). The substrates were selected at a 50:50 weight ratio and two single-stage digesters of 2 L capacity were used, operating under ideal thermophilic (55 °C) and mesophilic (35 °C) conditions. The HRTs studied were 30, 25, 20 and 15 days. The biomethane production reached 588 mL CH₄/d at 55 °C and 477 mL CH₄/d at 35 °C for an HRT of 15 days, indicating a significantly higher yield under the thermophilic process. The volatile solids removal efficiency ranged from 41% to 66% for the thermophilic digester and between 32% and 42% for the mesophilic digester. This further highlights the superior performance at higher temperatures. Full article

Microbial fuel cells (MFCs) are environmentally friendly energy converters that use electrochemically active bacteria (EAB) as catalysts to break down organic matter while producing bioelectricity. Traditionally, MFC research has relied on simple organic substrates, such as acetate, glucose, sucrose, butyrate, and glutamate, the production of which involves energy-intensive, CO₂-dependent processes and chemically aggressive methods. In contrast, nonconventional waste streams offer a more sustainable alternative as feedstocks, aligning with zero-waste and regenerative agricultural principles. This review highlights the potential of nonconventional organic wastes, such as fruit and vegetable wastes, raw human and livestock urine, and farm manure, as globally available and low-cost substrates for MFCs, particularly in household and farming applications at small-scale waste levels. Furthermore, complex waste sources, including hydrocarbon-contaminated effluents and lignin-rich industrial wood waste, which present unique challenges and opportunities for their integration into MFC systems, were examined in depth. The findings of this review reveal that MFCs utilizing nonconventional substrates can achieve power outputs comparable to traditional substrates (e.g., 8314 mW m⁻²–25,195 mW m⁻² for crude sugarcane effluent and raw distillery effluent, respectively) and even superior to them, reaching up to 88,990 mW m⁻² in MFCs utilizing vegetable waste. Additionally, MFCs utilizing hydrocarbon-containing petroleum sediment achieved one of the highest reported maximum power densities of 50,570 mW m⁻². By integrating diverse organic waste streams, MFCs can contribute to carbon-neutral energy generation and sustainable waste management practices. Full article