Search Results (67)

This review contains a compilation of data about the occurrence, mining, refining, and biological actions of lithium, without claiming completeness of knowledge. This should give a baseline for judging future pollutions of environmental and agricultural items and human nutrition and may show still existing gaps of screening. Emerging electromobility and use of computers leads to a steep increase in Li-based batteries, which are a source of hazardous waste unless recycled. Lack of recovery methods from effluents and sewage, however, will increase pollution with soluble Li-salts from increasing mining and waste in the future; therefore, biochemical effects of levels out of ambient range have been included. Many published data are hidden in multi-element tables, including the data of the author. Mobile fractions of soils and soil-to-plant transfer, as well as retainment in animal tissues, are low. A lot of data, starting from geology via soils, plants, water, and human nutrition, lead to a largely unknown average daily intake for men. With respect to nutrition of dairy cows, the contribution of Li from water was highest among all elements investigated, but only 4% of intake. Main sources for human nutrition are mineral water and table salt. Li is not labelled on mineral water bottles, nor table salt, which are the main sources. Though some data have been gathered, for human nutrition, the average daily intake is uncertain to estimate because some mineral waters are quite high in Li. Full article

An integrated process scheme is developed for valorizing filtered liquid digestates (FLD) from an industrial anaerobic digestion (AD) plant treating dairy-processing effluents with relatively low nutrient concentrations. The process scheme involves FLD treatment by nanofiltration (NF) membranes, followed by struvite recovery from the NF-retentate. An NF pilot unit (designed for this purpose) is combined with a state-of-the-art NF/RO process simulator. Validation of simulator results with pilot data enables reliable predictions required for scaling up NF systems. The NF permeate meets the standards for restricted irrigation and/or reuse. Considering the significant nutrient concentrations in the NF retentate (i.e., ~500 mg/L NH4-N, ~230 mg/L PO4-P), struvite recovery/precipitation is investigated, including determination of near-optimal processing conditions. Maximum removal of nutrients, through production of struvite-rich precipitate, is obtained at a molar ratio of NH₄:Mg:PO₄ = 1:1.5:1.5 and pH = 10 in the treated stream, attained through the addition of Κ₂HPO₄, ΜgCl₂·6H₂O, and NaOH. Furthermore, almost complete struvite precipitation is achieved within ~30 min, whereas precipitate/solid drying at modest/ambient temperature is appropriate to avoid struvite degradation. Under the aforementioned conditions, a significant amount of dry precipitate is obtained, i.e., ~12 g dry mass per L of treated retentate, including crystalline struvite. The approach taken and the obtained positive results provide a firm basis for further development of this integrated process scheme towards sustainable large-scale applications. Full article

Industrial activated sludge plants in many sectors, including the dairy industry, face sludge separation problems caused by sludge bulking. Aerobic granular sludge (AGS) could be a solution by forming well-settling granules. The key to successful granulation is the microbial selection of slow-growing glycogen-accumulating organisms (GAOs) by introducing an anaerobic feeding/reaction step. The objective of the current study was to investigate the impact of two slow feeding strategies to achieve granulation in existing sequencing batch reactors treating real dairy wastewater, by microbial selection only. The first strategy consisted of slow 90 min mixed feeding. The second strategy combined 45 min static and 45 min mixed feeding to build up a substrate gradient. The feeding strategies did not affect the effluent quality, but significantly impacted the sludge morphology, settling properties, and microbial community composition. Mixed feeding led to filamentous overgrowth by Thiothrix species, up to 45% abundance, and deteriorating settling, with sludge volume index (SVI) values up to 125 mL/g. In contrast, static feeding yielded densified sludge with SVI values below 45 mL/g and up to 35% GAO abundance. In conclusion, the results show successful granulation when using a simple static slow feeding mode, which could benefit the industrial application of AGS technology. Full article

The dairy industry generates substantial quantities of wastewater, primarily whey wastewater, posing environmental challenges. Current treatment methods involve physical, chemical, and biological processes, but efficient solutions are still sought. Biological treatments using microalgae are gaining attention due to their potential to remove pollutants from wastewater and generate valuable products, making them an alternative way to improve environmental sustainability. The physicochemical characterization of whey effluents reveals a high organic content, an acidic pH, and elevated nutrient levels. This study investigates the potential of Chromochloris zofingiensis (formerly known as Chlorella zofingiensis) for treating whey wastewater using three concentrations, 10%, 20%, and 50%, over a 7-day culture period. The optimal concentration of whey wastewater for biomass, nutrient removal, astaxanthin, and lipid production was found to be 10%. At this concentration, C. zofingiensis achieved a biomass of 3.86 g L⁻¹ and a removal efficiency of nutrients between 77.08% and 99.90%. Analysis of pigment production revealed decreases in chlorophyll and carotenoid production with increasing whey wastewater concentration, while lipid and astaxanthin production peaked at the 10% dilution. The chlorophyll a, chlorophyll b, total carotenoid, astaxanthin, and lipid contents were, respectively, 11.49 mg g⁻¹, 4.56 mg g⁻¹, 4.04 mg g⁻¹, 0.71 mg g⁻¹, and 30.49% in 10% whey wastewater. The fatty acid profiles indicated the predominance of saturated and unsaturated fatty acids, enhancing the biofuel potential of C. zofingiensis cultivated in whey wastewater. These findings demonstrate the dual benefit of using C. zofingiensis for sustainable whey wastewater treatment and high-value bioproduct generation, supporting the development of circular biorefinery systems. Full article

Microalgae cultivation in wastewater is a promising strategy for reducing nutrient loads and generating biomass that can be further exploited. Although microalgae grown under such conditions are not suitable for high-value applications, the resulting biomass can still be valuable for uses such as biofuels, biofertilizers, or animal feed. In this study, Chlorella sorokiniana was cultivated in dairy wastewater and, to the best of our knowledge, for the first time in a spent effluent from gas fermentation, to assess its potential as a sustainable growth medium. Growth kinetics and biomass productivity were evaluated at different dilution ratios, and it was found that high concentrations of ammonium and hexanol in undiluted effluents were inhibitory, while an optimized 50:50 dilution led to the highest biomass accumulation (1.96 g L⁻¹) and productivity (0.5 g L⁻¹ d⁻¹) of C. sorokiniana. This strategy significantly reduced the nitrogen (100%), phosphate (100%), sulfate (68%), and carbon (61%) contents, demonstrating effective bioremediation activity. Furthermore, the fatty acid profile revealed an increased polyunsaturated fatty acid fraction, enhancing the potential of C. sorokiniana biomass as a feed supplement. Overall, contributing to the circular bioeconomy, this approach is scalable and cost-effective, reducing freshwater and chemical dependency in microalgae biomass production. Full article

The rapid growth of the dairy industry has resulted in a significant increase in the generation of effluents, which are characterized by a high organic content that poses environmental challenges. In alignment with sustainable practices and the principles of the circular economy, this study investigates the valorization of cheese whey (CW) effluents through the cultivation of the microalga Dunaliella tertiolecta under mixotrophic conditions. The research aims to utilize cheese whey effluents as a supplemental growth medium to enhance the production of algal biomass and extracellular polymeric substances (EPSs). The results reveal that CW facilitated a 37% improvement in D. tertiolecta growth and led to an approximately eight times greater biomass productivity compared to under photoautotrophic conditions, while the EPS production increased by 30%. Chemical and techno-functional analyses of the microalgal biomass and EPSs suggest promising applications as natural product additives for the food industry. Biomass derived from photoautotrophic culture demonstrated greater antioxidant activity and total polyphenols content. Additionally, the lipid profile revealed 16 distinct fatty acids. On the other hand, biomass from the mixotrophic culture exhibited higher protein levels and eight fatty acids, indicating the influence of the cultivation mode on the biochemical composition. Regarding the EPSs, mixotrophic cultivation resulted in elevated antioxidant activity and total polyphenols content, as well as higher protein and sugar levels. Furthermore, the EPSs produced under mixotrophic conditions exhibited superior techno-functional properties compared to those of the photoautotrophic culture, making them ideal candidates for use as alternative natural food additives. Full article

Background/Objectives: The increasing threat of antimicrobial resistance (AMR) to global public health urgently needs attention. Misuse of antimicrobials in sectors such as dairy farming has led to the emergence and spread of resistant bacteria and genes. This study investigated AMR patterns and profiles of Escherichia coli (E. coli) from various sources, including soil, effluent, cow dung, and milk. Methods: A total of 192 samples were collected, comprising environmental samples (soil and effluent), cow dung samples, and milk samples from eight dairy farms in Selangor, Malaysia. The spread plate method was employed to isolate E. coli, and all the isolates were subjected to Gram staining to identify Gram-negative, rod-shaped bacteria. The Vitek^® 2 system was used for E. coli identification and susceptibility testing. Results: The prevalence of E. coli identified in the eight farms was 66.1%. A total of 360 E. coli isolates were successfully isolated, and 19.7% of the isolates presented AMR with ampicillin exhibiting the highest resistance (18.3%), followed by trimethoprim–sulfamethoxazole (8.9%). Additionally, 8.9% of them were multidrug resistant, which could be divided into 16 patterns. For the extended spectrum beta-lactamase screening, nine isolates were positive. Conclusions: This finding emphasizes the rise in resistant isolates in the growing dairy industry and underscores the urgency of addressing the potential reservoir of AMR. Therefore, essential measures such as continuous surveillance and effective antimicrobial stewardship programs are crucial for regulating veterinary antimicrobial use. Research on the mechanisms driving the development and dissemination of AMR is imperative for addressing One Health concerns. Full article

The development and implementation of innovative production technologies have a direct influence on the creation of new sources of pollution and types of waste. An example of this is the wastewater from soil-less agriculture and the effluent from microbial fuel cells. An important topic is the development and application of methods for their neutralisation that take into account the assumptions of global environmental policy. The aim of the present study was to determine the possibilities of utilising this type of pollution in the process of autotrophic cultivation of the biohydrogen-producing microalgae Tetraselmis subcordiformis. The highest biomass concentration of 3030 ± 183 mgVS/L and 67.9 ± 3.5 mg chl-a/L was observed when the culture medium was wastewater from soil-less agriculture. The growth rate in the logarithmic growth phase was 270 ± 16 mgVS/L-day and 5.95 ± 0.24 mg chl-a/L-day. In the same scenario, the highest total H₂ production of 161 ± 8 mL was also achieved, with an observed H₂ production rate of 4.67 ± 0.23 mL/h. Significantly lower effects in terms of biomass production of T. subcordiformis and H₂ yield were observed when fermented dairy wastewater from the anode chamber of the microbial fuel cell was added to the culture medium. Full article

The cheese industry produces substantial amounts of raw cheese whey wastewater (RW), which requires effective treatment prior to environmental disposal. This study presents an innovative sequential batch system that combines macrophyte and microalgal cultivation for RW remediation. The efficacy of Lemna minor MO23 in first-line photobioreactors (PBR-1) and Chlorella sp. MC18 (CH) or Scenedesmus sp. MJ23-R (SC) in second-line photobioreactors (PBR-2) for pollutant removal was evaluated. The nutrient removal capacity of L. minor, CH, and SC was assessed at optimal tolerance concentrations, alongside nutrient recovery from treated RW (TRW) by PBR-1 for microalgae biomass production. The results demonstrate that all three species effectively purified the cheese whey wastewater. L. minor efficiently removed COD, nitrate, phosphate, and sulfate from RW, producing TRW effluent suitable for microalgal growth. CH and SC further purified TRW, enhancing biomass production. CH outperformed SC with a 4.79% higher maximum specific growth rate and 20.95% higher biomass yield. Biochemical analyses revealed the potential of CH and SC biomass for applications such as biofuels and aquaculture. After treatment, the physicochemical parameters of the effluent were within the regulatory limits. This demonstrates that the PBR-1 and PBR-2 series-coupled system effectively purifies and recovers dairy effluents while complying with discharge standards. Full article

Cheese whey (CW), a byproduct resulting from dairy processing, requires proper treatment and disposal. The use of microalgae during tertiary treatment emerges as a promising option due to its efficiency to remove chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) from effluents obtained after secondary treatment processes. The present study was focused on treating CW effluent at two organic loads (C₁ and C₂—with different concentrations of COD, TN, and TP) (550–2200 mg·L⁻¹ of COD, 14–56 mg·L⁻¹ of TN, and 4.5–18 mg·L⁻¹ of TP) using the microalga Tetradesmus obliquus alone (C_M1 and C_M2) and in a consortium with the fungus Cuninghamella echinulata (C_MF1 and C_MF2), evaluating the residual values of COD, TN, and TP and removal efficiency. The experiments were carried out in an open system with a volumetric replacement ratio (VRR) of 40 and 60%. The C_M treatment showed residual values of COD in the range of 190–410 mg·L⁻¹ (removal efficiency: 57–68%), TN in the range of 6–24 mg·L⁻¹ (removal efficiency: 29–35%), and TP in the range of 0.90–3.0 mg·L⁻¹ (removal efficiency: 65–68%), after 7 days of volumetric replacement time (VRT) in a semicontinuous mode. In contrast, the consortium (C_MF) showed greater stability and efficiency in contaminant removal compared to the treatment system containing only the microalga, showing residual values of COD in the range of 61–226 mg·L⁻¹ (removal efficiency: 75–77%), TN in the range of 1.8–9.5 mg·L⁻¹ (removal efficiency: 70–74%), and TP in the range of 0.6–3.5 mg·L⁻¹ (removal efficiency: 66–70%), applying a lower VRT of 3 days and reaching the legislation standard for discharge to C_MF1 (VRR: 40 and 60%) and C_MF2 (VRR: 40%). The cell dry weight of 290–850 mg·L⁻¹ was obtained (microalga and microalga–fungus cultivation), which can be a valuable biomass for biotechnological applications. Finally, during microalga–fungus co-cultivation, there was greater system buffering (with less pH variation), ensuring a better system stability. Full article

The recovery concept of cleaning solutions, based on single-phase detergents from cleaning-in-place (CIP) effluents from the dairy industry, is presented. The first step consists of ultrafiltration (UF) (with a cut-off of 5 or 10 kDa) to reduce the high load of milk proteins, followed by nanofiltration (NF) (with a cut-off of 200 Da) to separate low molecular weight lactose. Membrane steps were performed in the concentration mode, achieving a recovery of 75% of the solutions. UF modules reduced 70–85% of chemical oxygen demand (COD), 99% of milk proteins, and 45–70% of lactose, limiting the susceptibility of NF modules to fouling. Combined with nanofiltration, the efficiency of the purification system is 100% for proteins and more than 99% for lactose. The solutions recovered in the proposed purification variants are recognized as sodium hydroxide solutions with a surfactant admixture, and they can be successfully re-used for cleaning processes in the production plant. Full article

The shift from fossil fuels to renewable energy sources is crucial in addressing environmental challenges. Vegetable oils have been focused on as the main potential source for biodiesel and biolubricant production. However, due to their fatty acid (FA) composition they are characterized by low stability to oxidation and variable viscosity. Single-cell oils (SCOs) from oleaginous microorganisms are a possible alternative to vegetable oils: their composition is more suitable, and it can further be improved by controlling the fermentation’s physiological conditions. In the present study, the production of SCOs with targeted technological properties from Lipomyces starkeyi in fermentation under controlled temperatures was assessed. A dairy effluent (scotta) was used as the fermentation substrate to improve the economic sustainability of the process. Batch aerobic fermentations were carried out in a fermenter at two different temperatures (25 °C and 30 °C). The fermentation yields and SCO FA profiles were analyzed. The highest yields of biomass (9.76 g L⁻¹) and microbial oil (1.83 g L⁻¹) were obtained from fermentations carried out at 30 °C. Furthermore, a significantly lower content (46% vs. 55%) of unsaturated FAs and higher content (11% vs. 1.5%) of shorter-chain saturated FAs, with myristic acid almost matching stearic acid, were detected at 30 °C in comparison to 25 °C. Very low peroxide values were also found (0.14 meq O₂ kg⁻¹ at 30 °C and 0 meq O₂ kg⁻¹ at 25 °C). These results indicate that these SCOs were highly oxidation-resistant, and that a higher fermentation temperature improves their oxidative stability and tribophysical features. The biodiesels’ technological properties, calculated from the FA composition, were within the limits of both U.S. standards and E.U. regulations. Then, SCOs produced from L. starkeyi by fermentation of dairy effluents carried out under controlled temperature can be considered a suitable alternative to vegetable oils to produce biodiesel and biolubricants. Full article

To determine the evolution of microbial community and microbial shift under anaerobic processes, this study investigates the use of denaturing gradient gel electrophoresis (DGGE). In the DGGE, short- and medium-sized DNA fragments are separated based on their melting characteristics, and this technique is used in this study to understand the dominant bacterial community in mesophilic and thermophilic anaerobic digestion processes. Dairy manure is known for emitting greenhouse gases (GHGs) such as methane, and GHG emissions from manure is a biological process that is largely dependent on the manure conditions, microbial community presence in manure, and their functions. Additional efforts are needed to understand the GHG emissions from manure and develop control strategies to minimize the biological GHG emissions from manure. To study the microbial shift during anaerobic processes responsible for GHG emission, we conducted a series of manure anaerobic digestion experiments, and these experiments were conducted in lab-scale reactors operated under various temperature conditions (28 °C, 36 °C, 44 °C, and 52 °C). We examined the third variable region (V3) of the 16S rRNA gene fingerprints of bacterial presence in anaerobic environment by PCR amplification and DGGE separation. Results showed that bacterial community was affected by the temperature conditions and anaerobic incubation time of manure. The microbial community structure of the original manure changed over time during anaerobic processes, and the community composition changed substantially with the temperature of the anaerobic process. At Day 0, the sequence similarity confirmed that most of the bacteria were similar (>95%) to Acinetobacter sp. (strain: ATCC 31012), a Gram-negative bacteria, regardless of temperature conditions. At day 7, the sequence similarity of DNA fragments of reactors (28 °C) was similar to Acinetobacter sp.; however, the DNA fragments of effluent of reactors at 44 °C and 52 °C were similar to Coprothermobacter proteolyticus (strain: DSM 5265) (similarity: 97%) and Tepidimicrobium ferriphilum (strain: DSM 16624) (similarity: 100%), respectively. At day 60, the analysis showed that DNA fragments of effluent of 28 °C reactor were similar to Galbibacter mesophilus (strain: NBRC 10162) (similarity: 87%), and DNA fragments of effluent of 36 °C reactors were similar to Syntrophomonas curvata (strain: GB8-1) (similarity: 91%). In reactors with a relatively higher temperature, the DNA fragments of effluent of 44 °C reactor were similar to Dielma fastidiosa (strain: JC13) (similarity: 86%), and the DNA fragments of effluent of 52 °C reactor were similar to Coprothermobacter proteolyticus (strain: DSM 5265) (similarity: 99%). To authors’ knowledge, this is one of the few studies where DGGE-based approach is utilized to study and compare microbial shifts under mesophilic and thermophilic anaerobic digestions of manure simultaneously. While there were challenges in identifying the bands during gradient gel electrophoresis, the joint use of DGGE and sequencing tool can be potentially useful for illustrating and comparing the change in microbial community structure under complex anaerobic processes and functionality of microbes for understanding the consequential GHG emissions from manure. Full article

Photosynthetic microbial fuel cells (pMFCs) are hybrid systems that enable simultaneous wastewater treatment under anaerobic conditions and the generation of electricity by utilizing the potential difference in the anaerobic anode chamber and the oxygenated cathode chamber. Dairy wastewater with a concentration of 2000 mg COD/L was treated in the anode of a batch pMFC. In the cathode chamber, Chlorella vulgaris or Arthrospira platensis was cultivated in synthetic medium, and next in diluted effluent from the anode chamber. The highest power density of 91 mW/m² was generated by the pMFC with the cultivation of Arthrospira platensis. Higher values of dissolved oxygen remained during the dark phase in the cathodic medium with Arthrospira platensis cultivation than with Chlorella vulgaris. This depletion of oxygen significantly decreased voltage generation, which during the light phase increased again to the maximum values. The COD removal achieved in the anodic chamber was 87%. The efficiency of nitrogen removal in the cathode chamber during the cultivation of Arthrospira platensis and Chlorella vulgaris was about 78% and 69%, respectively. The efficiency of phosphorus removal in the cathode chamber with the cultivation of Arthrospira plantensis and Chlorella vulgaris was 58% and 43%, respectively. This study has shown that the introduction of Arthrospira platensis into the cathode chamber is more effective than that of Chlorella vulgaris. Full article

Brewery (BW) and dairy (DW) wastewater are two types of agro-industrial wastewater that are generated in large amounts and, therefore, should be treated effectively and in an environmentally beneficial manner. Both these wastewater types are characterized by a high COD, BOD₅, and nutrient content, and conventional wastewater treatment methods such as an activated sludge process may prove to be inefficient due to the possibility of foaming, large biomass production, low activity at low temperatures, and risk of overloading the reactor with a load of organic pollutants. In the context of the described difficulties, anaerobic processes seem to be the best alternative. An interesting research area is the co-digestion of these wastewaters. However, this research direction, so far, has not been frequently reported. Given the gap in the current knowledge, this literature review aims to assess the possibility of BW and DW digestion in anaerobic reactors and provide up-to-date data on the post-treatment methods of effluent generated after the anaerobic digestion process. Despite numerous advantages, anaerobic treatment often requires post-effluent treatment to complete the treatment cycle. Full article