Piggery Wastewater Research Articles

Sustainable remediation of piggery wastewater using a novel mixotrophic Chlorella sorokiniana Cbeo for high value biomass production

Piggery wastewater (PW) contains high density of organic carbon (COD), nitrogen (NH4+-N and TN) and phosphorous (TP), which are essential nutrients for microalgae growth. This work was attempted to use a newly isolate Chlorella sorokiniana Cbeo for recovery these compounds into its biomass via mixotrophic cultivation. Critical factors including level of ammonia, C/N ratio, pH, light intensity, sterilized/unsterilized media, and indoor/outdoor cultivations affecting biomass production and nutrients removal efficiencies were investigated. Data revealed that C. sorokiniana Cbeo achieved the optimal growth in the unsterilized medium at NH4+-N concentration, C/N ratio, initial pH, and light intensity of 250mg/L, 10/1, 7, and 150 μmol/m2/s, respectively. Under the optimal conditions, dry cell weight (DCW) reached the maximal level of 4.30g/L, which was slightly higher than 4.14g/L determined for the sterilized medium. In 30 L-scale photobioreactor, C. sorokiniana Cbeo grown under indoor and outdoor achieved DCW of 3.61 and 3.19g/L, respectively. COD, NH4+-N, TN, TP removal efficiencies for both conditions were determined as 91.9–96.7, 96.6–99.7, 96.2–96.4, and 98.2–100%, respectively. The C. sorokiniana Cbeo biomass contained 14–27% lipid, 25–32% carbohydrate, 44–48% protein, and 0.25–0.97% lutein. Interestingly, α-Linolenic acid (C18:3n3) was 19.84 –27.0% of the total fatty acids. C. sorokiniana Cbeo is the promising algal strain for development of a sustainable biorefinery of PW.

Innovative Approach in Sustainable Agriculture: Harnessing Microalgae Potential via Subcritical Water Extraction

Microalgae can contribute to sustainable agriculture and wastewater treatment. This study investigated Tetradesmus obliquus, grown in piggery wastewater (To-PWW), as a biostimulant/biofertilizer compared to biomass grown in synthetic medium (To-B). Subcritical water extraction was tested for disruption/hydrolysis of wet biomass, at three temperatures (120, 170, and 220 ºC) and two biomass loads (1:10 and 1:80 (g dry biomass/mL water)). Extracts were evaluated for germination, and root formation/expansion. Residues were quantified for nutrient composition to assess their biofertilizer potential and tested for their affinity to oil compounds for bioremediation.The best germination was achieved by To-B extracts at 170 ºC (1:10: 148% at 0.2g/L, 1:80: 145% at 0.5g/L). Only To-PWW extracts at 0.2g/L had a significant germination effect (120 ºC: 120-123% for both loads; 170 ºC: 115% for 1:80). To-PWW extract at 120 ºC and 1:10 significantly affected cucumber and mung bean root formation (224 and 268%, respectively). Most extracts significantly enhanced root expansion, with all To-B extracts at 1:10 showing the best results (139-181%). The residues contained essential nutrients (NPK), indicating their biofertilizer potential, helping decrease synthetic fertilizers demands. To-B residues had high affinity to toluene and diesel but lower to used cooking and car oils. To-PWW showed very low affinity to all oil compounds. Finally, all residues were only able to form stable emulsions with the used car oil. This study fully exploits the use of microalgal biomass in sustainable agriculture, producing biostimulant extracts, and residues for biofertilizer and bioremediation, from a low-cost wastewater source.

Effect of integrated microbial fuel cell in a two-stage vertical flow constructed wetland for piggery wastewater treatment and resource recovery by photobioreactor

ABSTRACT This study developed a nature-based pilot-scale technology for simultaneous piggery WW treatment and resource recovery potential. The technology comprised a two-stage vertical flow constructed wetland (2-VFCW) integrated with a microbial fuel cell (MFC) and microalgal photobioreactor. The first and second stage was an unsaturated and saturated type, respectively. The bioelectricity generation was optimised by investigating the suitable electrode zonation, hydraulic retention time (HRT) and WW loading rate. The 2-VFCW-MFC-treated effluent was studied to grow microalgae for biomass production. The 2-VFCW-MFC showed better treatment efficiency than the 2-VFCW, possibly due to enhanced microbial activity on the electrode surface, leading to improved organic matter degradation and electron transfer to the cathode, enhancing NO3− and PO43− reduction. The 2-VFCW-MFC with electrode zonation of 20 cm (cathode) and 60 cm (anode) and HRT of 76 h, 48 min showed the highest open-circuit voltage of 291.83+13.53 mV and WW treatment efficiency. The highest algal biomass of 21,323.34+8,316.26 mg/L (wet weight) was produced at HRT of 96 h, then entered the death phase. Comparatively, the 2-VFCW-MFC showed higher WW treatment efficiency than 2-VFCW at 2 L/day by 23.24% COD, 27.43% TOC, 33.05% PO43−, 13.51% NO3−, 8.14% TN, except TAN (22.71%).

Bioprocess to produce biostimulants/biofertilizers based on microalgae grown using piggery wastewater as nutrient source

In the present work, two downstream processes − high-pressure homogenization at 100 (HPH-100) and 1200 bar (HPH-1200), and enzymatic hydrolysis (EH) − were tested to produce biostimulant extracts from Tetradesmus obliquus grown in piggery wastewater at two concentrations (12.8 and 88.3 g/L). Extracts before and after centrifugation (C) were evaluated in four bioassays using garden cress (germination), mung bean (auxin-like activity), and cucumber (auxin- and cytokinin-like activity) relative to distilled water. The initial microalgal culture, without any treatment, had the best germination results (162 % at 0.2 g/L) and the only one that showed cytokinin-like activity (141 % at 0.5 g/L). In both auxin-like bioassays, the HPH-1200 + C and EH + C originated high values (186 and 155 % for cucumber, 290 and 285 % for mung bean, respectively). For mung bean, the HPH-1200 achieved the highest auxin-like effect (378 %). Finally, the extracted biomass contained essential nutrients for biofertilization, complementing the biostimulant extracts for sustainable agriculture application.

Synergistic treatment of digested wastewater with high ammonia nitrogen concentration using straw and microalgae

Microalgae as a promising approach for wastewater treatment, has challenges in directly treating digested piggery wastewater (DPW) with high ammonia nitrogen (NH4+-N) concentration. To improve the performance of microalgae in DPW treatment, straw was employed as a substrate to form a straw-microalgae biofilm. The results demonstrated that the straw-microalgae biofilm achieved the highest NH4+-N removal rate of 193.2 mg L−1 d−1, which was 28.8 % higher than that of culture system without straw. The final NH4+-N concentration in the effluent met the discharge standard of 5 mg L−1. Furthermore, the total organic carbon (TOC) released from straw facilitated bacterial proliferation and the secretion of extracellular polymeric substances (EPS). The EPS and TOC increased the suspension viscosity and surface tension, thereby enhancing the residence time of CO2 in the liquid phase and promoting CO2 fixation. This study presented a novel method for the biological treatment of high-ammonia–nitrogen DPW.

The Effect of Diurnal Temperature Fluctuations on the Decay of Japanese Encephalitis and Murray Valley Encephalitis Virus RNA Seeded in Piggery Wastewater

The Effect of Diurnal Temperature Fluctuations on the Decay of Japanese Encephalitis and Murray Valley Encephalitis Virus RNA Seeded in Piggery Wastewater

Anaerobic hybrid-photobioreactor using phototrophic purple and green bacteria treating piggery wastewater with sulfur recovery and biogas polishing

An anaerobic hybrid-photobioreactor (AnHPBR) was performed for biogas polishing during piggery wastewater treatment. AnHPBR was exposed to high (4.45 × 105 lx) and low (450 lx) light intensities for growing purple and green sulfur phototrophs separately in each chamber of AnHBBR for soluble sulfide removals. Four phases of hydraulic retention times (HRT, h): 24, 48, 96, and 96 (with added sulfate) of piggery wastewater were operated consecutively for 351 days. Metagenomic analysis of the AnHPBR biomass confirmed that purple and green bacteria were 63–82 %, of which the species varied by HRT and sulfate loadings. In sum, 96 h HRT for AnHPBR presented the highest efficacies in removals of COD (92 %), sulfate (73 %), and sulfide (59 %). Its biogas contained high methane (75 %) and low hydrogen sulfide (0.3 %). Additionally, AnHPBR produced outflow biosolids with a stable sulfur content of 1.88 %.

Effects of rice husk biochar attachment biofilm with microorganisms on nitrogen removal of digested swine wastewater

Nitrogen in digested swine wastewater is currently difficult to directly degrade by an activated sludge process in a sequencing batch reactor (SBR), with resulting failure of the effluent to meet emission standards. In this study, rice husk biochar was optionally added into SBR to enhance biochemical properties for digested swine wastewater, especially for nitrogen degradation. The relative nitrogen removal mechanism for microbial community was probed by means of high-throughput sequencing. The results indicated that chemical oxygen demand (COD), ammonia (NH4+-N), and total nitrogen (TN) removal efficiency of digested swine wastewater was separately at 85.3%, 81.3%, and 65.2% using rice husk biochar with biofilm, which was 3.5%, 24.4%, and 14.7% higher than that of activated sludge, under influent of 2609 mg·L-1 COD, 337.0 mg·L-1 NH4+-N, 344 mg/L TN, and 7.77 C/N. High-throughput sequencing revealed that rice husk biochar with biofilm contained Proteobacteria, Thauera, Comamonas, Acinetobacter, Pseudomonas, Flavobacterium, and Corynebacterium to enhance nitrogen removal of digested swine wastewater. The results not only provide theoretical support for biochar with biofilm to improve digested piggery wastewater treatment, but also have great significance in resource utilization of agricultural waste and eco-environmental protection.

Effects of mixed LED light wavelengths and strigolactone analog concentrations on integral biogas upgrading and antibiotic removal from piggery wastewater by different microalgae-bacteria-fungi consortia

This study investigated the combined effects of mixed LED light wavelengths and varying concentrations of the strigolactone analog (GR24) on methane and antibiotic removal in swine wastewater using different microalgae co-culture techniques. Four treatments were implemented: Treatment 1 involved Chlorella vulgaris monocultures, Treatment 2 included C. vulgaris-activated sludge-Clonostachys rosea (C. rosea), Treatment 3 included C. vulgaris-Bacillus licheniformis-C. rosea, and Treatment 4 included C. vulgaris-S395-2-C. rosea. These treatments were designed to optimize conditions for antibiotic and CO2 removal. Treatment 4 showed the highest growth rate (0.329 ± 0.030 d−1), mean daily productivity (0.166 ± 0.015 g L−1 d−1), CA activity (66.25 ± 5.39), and photosynthesis under a red-to-blue light ratio of 5:5. Significant antibiotic removal rates were achieved: 98.77 ± 1.05 % for tetracycline hydrochloride, 93.74 ± 5.06 % for oxytetracycline hydrochloride, 62.44 ± 5.58 % for ciprofloxacin, 55.07 ± 4.97 % for norfloxacin, 70.39 ± 6.03 % for sulfadimethoxine, and 67.46 ± 6.25 % for sulfamethoxazole. A concentration of 10−9 M GR24 maximally enhanced antibiotic and CO2 removal in Treatment 4. This study provided valuable insights into improving wastewater treatment practices and environmental management.

Aerobic Granular Sludge Treatment of Piggery Wastewater: Solution to the Problem of Non-Filamentous Bulking and Analysis of Microbial Community Structure in Practical Application

Aerobic Granular Sludge Treatment of Piggery Wastewater: Solution to the Problem of Non-Filamentous Bulking and Analysis of Microbial Community Structure in Practical Application

Development of an artificial neural network (ANN) for the prediction of a pilot scale mobile wastewater treatment plant performance

Productive activities such as pig farming are a fundamental part of the economy in Mexico. Unfortunately, because of this activity, large quantities of wastewater are generated that have a negative impact in the environment. This work shows an alternative for treating piggery wastewater based on advanced oxidation processes (Fenton and solar photo Fenton, SPF) that have been probed successfully in previous works. In the first stage, Fenton and SPF were carried out on a laboratory scale using a Taguchi L9-type experimental design. From the statistical analysis of this design, the operating parameters: pH, time, hydrogen peroxide concentration [H2O2], and iron ferrous concentration [Fe2+] that maximize the response variables: Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), and color were chosen. From these, a cascade forward neural network was implemented to establish a correlation between data from the variables to the physicochemical parameters to be measure being that a great fit of the data was obtained having a correlation coefficient of 0.99 which permits to optimize the pollutant degradation and predict the removal efficiencies at pilot scale but with a projection to a future industrial scale. A relevant result, it was found that the optimal values for maximizing the removal of physicochemical parameters were pH = 3, time = 60 min, H2O2/COD = 1.5 mg L−1, and H2O2/Fe2+ = 2.5 mg L−1. With these conditions degradation percentages of 91.44%, 47.14%, and 97.89% for COD, TOC, and color were obtained from the Fenton process, while for SPF the degradation percentage increased moderately. From the ANN analysis, the possibility to establish an intelligent system that permits to predict multiple results from operational conditions has been achieved.

Impact of truncated modified basalt fibers on aerobic granular sludge stability and pollutant removal in piggery wastewater treatment

Modified basalt fibers (MBF) and carbon fibers (CF) are effective bio-carrier materials that enhance wastewater treatment performance. This study explored the use of two lengths of truncated MBF and CF (0.1 and 0.4 mm) in a sequencing batch reactor to support activated sludge treatment, facilitating the formation of aerobic granular sludge (AGS). This approach aimed to enhance the stability and pollutant removal efficiency of AGS, particularly for treating piggery wastewater (PWW). The study further assessed the impact of adding truncated fibers on AGS formation, stability, and its chemical oxygen demand (COD) and total nitrogen (TN) removal capabilities. Results indicate that truncated MBF notably enhanced sludge activity, promoting the secretion of extracellular polymeric substances (EPS) within AGS. This process further increased the protein/polysaccharide ratio and bolstered AGS stability. Specifically, the addition of 0.1 mm MBF boosted PWW treatment efficiency. Fluorescence in situ hybridization (FISH) revealed that the addition of fibers had a minimal impact on the distribution of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) within AGS, although truncated MBF enriched the population of AOB. Microbial community analysis showed that the addition of MBF favored the enrichment of bacteria associated with nitrogen removal, upregulating the tricarboxylic acid cycle, nitrogen and amino acid metabolism. Overall, truncated MBF significantly improved AGS stability and its effectiveness in PWW treatment.

Unlocking the potential of Euglena gracilis cultivated in piggery wastewater: biomass production, nutrient removal, and biostimulant potential in lettuce and tomato plants

Unlocking the potential of Euglena gracilis cultivated in piggery wastewater: biomass production, nutrient removal, and biostimulant potential in lettuce and tomato plants

Improving antibiotic resistance removal from piggery wastewater by involving zero-valent iron within an integrated anoxic-aerobic biofilm reactor

This study introduces zero-valent iron (ZVI) to enhance the removal of antibiotic resistance in piggery wastewater. Two integrated anoxic-aerobic biofilm reactors (IAOBRs) were operated simultaneously for 120 days, with one serving as a control reactor and the other as experimental reactor supplemented with ZVI. The experimental reactor demonstrated superior antibiotic removal efficiencies (89.8 ± 4.5 %), eliminating 99.7 ± 0.7 % of sulfonamides, 91.6 ± 4.5 % of tetracyclines and 81.1 ± 8.4 % of quinolones. The antibiotic resistance bacteria, antibiotic resistance genes (ARGs) and mobile genetic elements removal efficiency reached 0.69–1.74, 2.06 and 2.15 logs, respectively. In comparison to the control reactor, the activated sludge in the experimental reactor also experienced a reduction in total antibiotic concentrations by 57.58 ± 19.99 %. The enhanced performance of the iron-mediated process in antibiotic resistance removal is attributed to the augmentation of enzymatic activity, biodegradation ability, and enrichment of specific microorganisms. The introduction of ZVI also modified the microbial community composition and decreased the potential hosts of ARGs. The proposed iron-mediated process greatly enhances antibiotic resistance removal from wastewater and mitigates antibiotic accumulation in activated sludge, offering new insights into wastewater biological treatment for eliminating antibiotic resistance.

Mechanism of microplastics effects on the purification of heavy metals in piggery effluents by microalgae

Microalgae is an effective bioremediation technique employed for treating piggery effluent. However, there is insufficient study on how the presence of microplastics (MPs) in wastewater affects the ability of microalgae to remove heavy metals from piggery effluent. This study aims to investigate the influence of two prevalent heavy metals found in piggery wastewater, Cu2+ (2 mg/L) and Zn2+ (2 mg/L), on their removal by microalgae (Desmodesmus sp. CHX1) in the presence of four types of MPs: polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), and polyethylene terephthalate (PET). The results revealed that smaller particle size MPs promoted chlorophyll accumulation, while larger particles inhibits it. Additionally, higher concentrations of MPs promoted chlorophyll accumulation, while lower concentrations inhibited it. As for heavy metals, the presence of microplastics reduced the removal efficiency of Cu2+ and Zn2+ by Desmodesmus sp. CHX1. The highest inhibition of Cu2+ was 30%, 10%, 19%, and 16% of the control (CK), and the inhibition of Zn2+ was 7%, 4%, 4%, and 13%, respectively, under the treatments of PE, PVC, PP and PET MPs. Furthermore, Desmodesmus sp. CHX1 can secrete more extracellular polymeric substances (EPS) and form heterogeneous aggregates with MPs to counteract their pressure. These findings elucidate the impact of MPs on microalgae in bioremediation settings and offer useful insights into the complex relationships between microalgae, MPs, and heavy metals in the environment.

Veterinary antibiotics and metals impact the mass, composition and hydrolysis of biomass cultivated in piggery wastewater treatment photobioreactors

Photobioreactors are a promising alternative for piggery wastewater treatment which allows to produce valuable biomass, but the presence of antibiotics or heavy metals in the pig manure can influence the biomass composition and the posterior valorization processes. This study evaluates the effect of these pollutants on mass, composition and hydrolysis yields of the consortia of microalgae and bacteria obtained in a 1280 L photobioreactor treating pig manure. The photobioreactor feed was doped with 1) veterinary antibiotics; 2) copper, zinc, and arsenic; and 3) combination of both pollutants. The pollutants presence decreased the mass of biomass grown in the photobioreactor by up to 35% while glucose content of the biomass by up to 42% and increased protein and xylose by 30% and 16% due to oxidative stress. Likewise, they increased the protein solubilization yield by acid hydrolysis at 120 ºC by 32% while reduced glucose solubilization by 49% after alkaline hydrolysis at 120 ºC. Applying enzymatic hydrolysis and ultrasound assisted enzymatic extractions, glucose and xylose recoveries were drastically reduced in presence of heavy metals (∼100%). Antibiotics increased xylose solubilization by ultrasonication (74%), but also its degradation, decreasing xylose recovery. Thus, the presence of all these pollutants in pig manure affected biomass production and valorization and these results must be considered for biorefinery processes.

Recovery potential of aerobic sludge biomass stressed with Cu(II) laden piggery wastewater

Piggery wastewater (PWW) contains a variety of pollutants, and lack of treatment infrastructure in piggery farms often results in the discharge of PWW into nearby drains, eventually reaching sewage treatment plants. It may adversely affect the sludge biomass of the treatment plants. This study investigated the effects of prolonged exposure to PWW and copper-laden (40 and 80 mg/L) PWW on the quality of sludge biomass. The results revealed that PWW-exposed reactors experienced a significant decrease in COD removal (65–76% compared to 95% in the control reactor). Additionally, there were changes in sludge characteristics, including a decreased sludge volume index (SVI) and an increased interface settling velocity (ISV). Further addition of PWW+Cu(II) stress significantly reduced COD removal (8–29%), the filamentous index and also lowered cell viability and enzyme activity. However, partial recovery was observed after discontinuing PWW+Cu(II) exposure, particularly at 40 mg/L of Cu(II) concentration. The study is significant for practical wastewater treatment, as it deals with multi-stress conditions caused due to Cu(II) metal laden piggery wastewater. The investigation recommends preliminary tests (microscopic examination and aerobic sludge biomass activity test) and confirmatory tests (cell viability tests and amplified ribosomal DNA restriction analysis) to be used for the evaluation of aerobic sludge biomass quality.

Fe-Mn binary oxides improve the methanogenic performance and reduce the environmental health risks associated with antibiotic resistance genes during anaerobic digestion

Increasing evidence indicates that metal oxides can improve the methanogenic performance during anaerobic digestion (AD) of piggery wastewater. However, the impacts of composite metal oxides on the methanogenic performance and risk of antibiotic resistance gene (ARG) transmission during AD are not fully understood. In this study, different concentrations of Fe-Mn binary oxides (FMBO at 0, 250, 500, and 1000 mg/L) were added to AD to explore the effects of FMBO on the process. The methane yield was 7825.1 mL under FMBO at 250 mg/L, 35.2% higher than that with FMBO at 0 mg/L. PICRUSt2 functional predictions showed that FMBO promoted the oxidation of acetate and propionate, and the production of methane from the substrate, as well as increasing the abundances of most methanogens and genes encoding related enzymes. Furthermore, under FMBO at 250 mg/L, the relative abundances of 14 ARGs (excluding tetC and sul2) and four mobile gene elements (MGEs) decreased by 24.7% and 55.8%, respectively. Most of the changes in the abundances of ARGs were explained by microorganisms, especially Bacteroidetes (51.20%), followed by MGEs (11.98%). Thus, the methanogenic performance of AD improved and the risk of horizontal ARG transfer decreased with FMBO, especially at 250 mg/L.

Insights into the microbiological mechanism of antibiotic removal in an aerobic-microaerobic process treating manure-free piggery wastewater

A process integrating the sequencing batch reactor (SBR) and up-flow microaerobic sludge reactor (UMSR) has been innovatively developed to effectively remove antibiotics from manure-free piggery wastewater. This study provides a comprehensive analysis of bacteria, genes, and enzymes crucial for antibiotic biodegradation to reveal the underlying microbiological mechanism of antibiotic removal. During the 230-day operational period, a significant succession of microbial communities was observed in the SBR-UMSR system. Intriguingly, microbial interactions were pivotal in dominating the community succession, accounting for a substantial contribution of 69.12%, while abiotic factors only accounted for 30.88%. The analysis of the microbial community and network revealed that the predominant mechanism for antibiotic biodegradation in the SBR-UMSR system was driven by the metabolic activities of heterotrophic bacteria. More denitrifying bacteria were involved in antibiotic biodegradation than ammonia-oxidizing bacteria. In SBR, most of the potential antibiotic-degrading bacteria (PADB) were Gram-positive and facultatively anaerobic, whereas in UMSR, they were Gram-negative and aerobic. Propioniciclava and Norank_f__AKYH767 were the dominant PADB in the SBR and UMSR, respectively. Network analysis pinpointed redox reactions, transfer processes, and hydrolysis reactions as the core processes facilitating antibiotic biodegradation. Despite a general decrease in the abundance of most antibiotic resistance genes (ARGs) in the activated sludge of both SBR and UMSR over the 230-day operation, there was a notable enrichment in multidrug resistance genes. This underlines the necessity for proper sludge management to prevent secondary contamination by ARGs. This research provides deep insights into the mechanisms of antibiotic removal in intricate microbial ecosystems.

Enhancement of sulfide removal and sulfur recovery in piggery wastewater via lighting-anaerobic digestion with bioaugmentation of phototrophic green sulfur bacteria.

Anaerobic pig wastewater treatment commonly generates high sulfide concentrations in the treated wastewater. This study aims to apply phototrophic green sulfur bacteria (PGB) to promote sulfide removal in lighting-anaerobic digestion (lighting-AD) treating pig wastewater. Initially, batch AD tests of pig wastewater with/without PGB addition were carried out under dark (D) and light (L) conditions. The results showed that the lighting-AD with PGB gave a higher growth rate of PGB (0.056h-1) and the highest COD/sulfide removals as compared to the dark-AD with PGB and lighting-AD solely. More experiments under various light intensities were performed in order to find an optimal intensity for PGB growth concurrently with metagenomic changes concerning treatment performance. It appeared that sulfide removal rates had increased as increasing light intensity up to 473lx by giving the highest rate of 12.5mg L-1 d-1 with the highest sulfur element content in the biomass. Contrastingly, many PGB species disappeared at 1350lx exposure subsequently sharply decreasing the rate of sulfide removal. In sum, the application of low light intensities of 400-500lx with bioaugmented PGB could promote PGB growth and activity in sulfide removal in pig wastewater in the lighting of the AD process.