Swine Farm Wastewater Research Articles

Exploring bacterial diversity and antimicrobial resistance gene on a southern Brazilian swine farm

The bacterial composition of and the circulation of antimicrobial resistance genes (ARGs) in waste from Brazilian swine farms are still poorly understood. Considering that antimicrobial resistance (AMR) is one of the main threats to human, animal, and environmental health, the need to accurately assess the load of ARGs released into the environment is urgent. Therefore, this study aimed to characterize the microbiota in a swine farm in southern Brazil and the resistome in swine farm wastewater treated in a series of waste stabilization ponds (WSPs). Samples were collected from farm facilities and the surrounding environment, representing all levels of swine manure within the treatment system. Total metagenomic sequencing was performed on samples from WSPs, and 16S-rDNA sequencing was performed on all the collected samples. The results showed increased bacterial diversity in WSPs, characterized by the presence of Caldatribacteriota, Cloacimonadota, Desulfobacterota, Spirochaetota, Synergistota, and Verrucomicrobiota. Furthermore, resistance genes to tetracyclines, lincosamides, macrolides, rifamycin, phenicol, and genes conferring multidrug resistance were detected in WSPs samples. Interestingly, the most abundant ARG was linG, which confers resistance to the lincosamides. Notably, genes conferring macrolide (mphG and mefC) and rifamycin (rpoB_RIF) resistance appeared in greater numbers in the late WSPs. These drugs are among the high-priority antibiotic classes for human health. Moreover, certain mobile genetic elements (MGEs) were identified in the samples, notably tnpA, which was found in high abundance. These elements are of particular concern due to their potential to facilitate the dissemination of ARGs among bacteria. In summary, the results indicate that, in the studied farm, the swine manure treatment system could not eliminate ARGs and MGEs. Our results validate concerns about Brazil's swine production system. The misuse and overuse of antimicrobials during animal production must be avoided to mitigate AMR.

Characterization of simultaneous removal of nitrogen and phosphorus by novel Raoultella ornithinolytica strain YX-4 and application in real farm wastewater treatment

A novel strain having ability to simultaneously remove ammonium nitrogen, nitrate nitrogen, nitrite nitrogen and phosphorus was isolated from swine farm wastewater and was identified as Raoultella ornithinolytica YX-4 (NCBI accession number: OR646540). Nitrogen and phosphorus balance analysis combined with amplification of key enzyme genes of metabolic pathways revealed that the strain possess heterotrophic nitrification, aerobic denitrification, phosphorus accumulation and assimilation pathways. Significant removal of ammonium nitrogen, nitrate nitrogen and nitrite nitrogen were achieved (99%, 97% and 93% respectively) with optimal culture conditions. The transcript level of key enzyme genes was detected at different incubation period, and significant up-regulation of glnA, narI, narH, nirB, nirD, ppk1, and ppk2 was noted. This is the first report of the denitrification of phosphorus accumulating organisms R. ornithinolytica and reveals tangible results of key enzyme gene expression during real wastewater treatment.

Grain Yield of Maize Crops under Nitrogen Fertigation Using Wastewater from Swine and Fish Farming

Maize is one of the most important cereals in the world. It is a crop demanding in nitrogen. Therefore, alternative sources of fertilization bring agronomic, environmental and economic benefits. The objective of this study was to evaluate the biomass and productivity of maize fertigated with wastewater from swine and fish farming in different dilutions. The soil used is classified as Dystroferric Red Latosol, Cerrado phase, with clayey texture. The experimental design used was randomized blocks in 2 × 4 split plots with three replications. The treatments consisted of two sources of wastewater (fish farming and swine farming) diluted with the recommended dose of wastewater + 0, 25, 50 and 75% of its volume in water. The accumulation of dry mass (leaf, stalk and aerial parts) was evaluated at 30, 60, 90 and 110 days after sowing. The evaluation of yield variables (number of grain rows, number of grains per row, grain sizes, grain dry weight, gran yield and harvest index) occurred at 130 days after sowing. The largest accumulation of dry biomass at the end of the maize cycle and evaluated productivity variables were obtained with the application of swine farming wastewater. Wastewater from fish farming applied via an irrigation system without dilution (0%) is the most suitable for obtaining the productivity of corn grains. The two sources of wastewater have the potential to partially replace mineral nitrogen fertilizer in maize.

Antibiotic removal from swine farming wastewater by anaerobic membrane bioreactor: Role of hydraulic retention time

This study investigated the impact of hydraulic retention time (HRT) on the removal of veterinary antibiotics by an anaerobic membrane bioreactor (AnMBR) for swine wastewater treatment. Ten commonly used antibiotics in the group of tetracyclines, fluoroquinolones, and sulfonamides were evaluated. Results show that a wide variation from 21 to 99% was observed for antibiotic removal by AnMBR regardless of the applied HRT. The methane yield increased from 0.22 L/g COD to 0.28 L/g COD as the operational HRT was prolonged from 24 to 48 h for AnMBR. Doubling the HRT value enhanced removal of most antibiotics and methane yield by 2–30% and 22–47%, respectively. The enhanced antibiotic removal in response to HRT prolongation could be positively correlated to the enrichment of the genus unidentified_Synergistaceae. Moreover, prolonging HRT increased the relative abundance of the genera unidentified_Synergistaceae, Geobacter and Methanobrevibacter, which could strengthen hydrogenotrophic methanogenesis to enhance methane yield. In addition, HRT increase reduced the ratio of protein to polysaccharide in both extracellular polymeric substances and soluble microbial products, thereby, alleviating membrane fouling in AnMBR operation.

Ecological risk under the dual threat of heavy metals and antibiotic resistant Escherichia coli in swine-farming wastewater in Shandong Province, China

Mineral elements and antibiotic-resistant bacterial pollutants in livestock and poultry farms’ wastewater are often sources of ecological and public health problems. To understand the heavy-metal pollution status and the characteristics of drug-resistant Escherichia coli (E. coli) in swine-farm wastewater in Shandong Province and to provide guidance for the rational use of mineral-element additives, common antibiotics, and quaternary ammonium compound disinfectants on swine farms, 10 mineral elements were measured and E. coli isolated from wastewater and its resistance to 29 commonly used antibiotics and resistance genes was determined. Finally, phylogenetic and multi-locus sequence typing (MLST) analyses was performed on E. coli. The results showed serious pollution from iron and zinc, with a comprehensive pollution index of 708.94 and 3.13, respectively. It is worth noting that average iron levels in 75% (12/16) of the districts exceed allowable limits. Multidrug-resistant E. coli were found in every city of the province. The E. coli isolated from swine-farm wastewater were mainly resistant to tetracyclines (95.3%), chloramphenicol (77.8%), and sulfonamides (62.2%), while antibiotic resistance genes for quinolones, tetracyclines, sulfonamides, aminoglycosides, and β-lactams were all more than 60%. The clonal complex 10 (CC10) was prevalent, and ST10 and ST48 were dominant in E. coli isolates. Multidrug-resistant E. coli were widely distributed, with mainly A genotypes. However, the mechanism of the effect of iron on antibiotic resistance needs more study in this area. Thus, further strengthening the prevention and control of iron and zinc pollution and standardizing the use of antibiotics and mineral element additives in the swine industry are necessary.

Design, application and verification of a novel system utilizing bacteria and microalgae to treat swine farm wastewater and produce value-added biomass

Design, application and verification of a novel system utilizing bacteria and microalgae to treat swine farm wastewater and produce value-added biomass

Iron-rich sludge biochar triggers sodium percarbonate activation for robust sulfamethoxazole removal: Collaborative roles of reactive oxygen species and electron transfer

The efficient removal of sulfamethoxazole (SMX) from swine farming wastewater is a major emerging environmental issue. This study successfully developed Fe-rich sludge biochar (Fe-BC) from dewatered iron-containing sewage sludge cake, in order to activate sodium percarbonate (SPC) for rapid SMX degradation in swine farming wastewater. Under optimal conditions of 0.5 g/L Fe-BC and 0.3 mM SPC at pH of 3.0, Fe-BC/SPC process achieved highly efficient SMX degradation within 5 min, reaching 100 % SMX degradation efficiency with kobs of 1.1439 min−1. The Fe-BC/SPC process exhibited recyclability and a high level of resistance to natural wastewater conditions. The main mechanism included adsorption and oxidation process. The SMX was probably adsorbed on the Fe-BC surface. Also, SPC activation by Fe-BC for SMX degradation was found to include a radical-driven pathway dominated by •OH and a non-radical pathway governed by direct electron transfer. Furthermore, the high rate of SMX degradation in the Fe-BC/SPC process was attributed to Fe2+ generation via the Fe3+/Fe2+ cycle and efficient electron transfer through oxygenated functional groups. Four SMX degradation pathways (i.e., hydroxylation, –NH2 group oxidation, ON bond and NS bond cleavage reactions) were proposed. The Fe-BC/SPC process exhibited high SMX removal performance and low-toxicity with swine farming wastewater. Overall, this study shows that the development of Fe-BC/SPC as a promising and efficient system for SMX degradation in practical swine farming wastewater treatment applications.

Synergistic adsorption-photocatalytic activity using Z-scheme based magnetic ZnFe2O4/CuWO4 heterojunction for tetracycline removal

Developing efficient and economical photocatalysts was considered as an efficient and economical strategy for pollution remediation. Herein, magnetically separable ZnFe 2 O 4 /CuWO 4 composites (ZW) had been developed via combining ZnFe 2 O 4 with CuWO 4 . The composite with a mass ratio of 40% CuWO 4 (ZW-40) performed best, and the tetracycline hydrochloride (TC) removal by adsorption-photocatalysis of ZW-40 reached 86.5%. The photocatalytic degradation rated constant of it was 9.44 × 10 −3 min −1 , which was approximately 5.04 and 3.28 times compared to the ZnFe 2 O 4 and CuWO 4 samples, respectively. Pseudo-second-order kinetic models could describe well the TC adsorption process, in which chemisorption was the major driving factor, with the maximum adsorption at 23.56 mg g −1 . The improved photo-catalytic capability owed to the formation of Z-scheme heterojunctions with ZnFe 2 O 4 and CuWO 4 , which improved the intensity of visible light absorption and enhanced the separation electron-hole pairs as well as the redox capability of the composite. ZW-40 was high stability as its removal ability of TC in different water conditions slightly dropped about 15% after 5 cycles. ZW-40 could effectively remove TC in different water matrix, its removal ability for 40 mg/L was as follows: super-pure water> municipal wastewater> swine farm wastewater. Hence, the complexation of ZnFe 2 O 4 with CuWO 4 provides a valuable strategy to improve the photocatalytic potential for ZnFe 2 O 4 -based catalysts as well as providing a promising pathway for water clarification. • A novel ZnFe 2 O 4 /CuWO 4 (ZW) Z-scheme heterojunction was successfully constructed. • Heterojunction between ZnFe 2 O 4 and CuWO 4 promotes the electron-hole pair separation. • Synergistic adsorption-photocatalysis could more effectively remove tetracycline. • The ZW composite was relatively effective to remove TC from the wastewater.

Recycling rice husk for removal of phosphate and nitrate from synthetic and swine wastewater: Adsorption study and nutrient analysis of modified rice husk

The objective of this study was to determine the adsorbent potential of rice husk and its modified form for phosphate and nitrate removal from synthetic and swine-farm wastewater. The mechanism of adsorption as well as the potential of phosphate-/nitrate- adsorbed rice husk as nutrient rich residue was also investigated. Two-step modification of RH (using base-washing (BW) and chemical modification (CM) was conducted to compare the phosphate and nitrate removal. The effects of several factors (pH, sorbent dosage, contact time, initial concentration, and coexistence of both ions) were investigated to gain insight into the adsorption rate, behavior, and mechanism of the modified RH regarding phosphate and nitrate removal. The results of Fourier-transform infrared spectroscopy showed that the modification was successful by crosslinking with the amine group of the chemical agent. Fitting the adsorption kinetic data of phosphate showed physical adsorption, intraparticle diffusion, and chemisorption, whereas for nitrate, the data indicated mainly chemisorption. Fitting the adsorption isotherm data of phosphate and nitrate together showed adsorption on a monolayer coating of anions on the homogeneous sorbent’s surface. The maximum phosphate and nitrate adsorption capacities were 6.94 and 2.46 mg/g, respectively, for a single adsorbate and 11.14 and 1.76 mg/g, respectively, for the binary solution. In real swine wastewater, removal efficiencies of phosphate, nitrite, nitrate, sulfate, and ammonia were 83.8%, 65.0%, >45.0%, 36.6%, and 2.6%, respectively, indicating that the modified RH would be effective for phosphate and nitrate removal from real wastewater. Finally, nutrient analysis of the phosphate- and nitrate-sorbed RH showed increases in nitrogen and phosphorus, which would be beneficial for further use of the RH as nutrient or fertilizer after adsorption.

Using vermiwash to enhance performance of small-scale vermifiltration for swine farm wastewater.

Pollution caused by swine wastewater is a growing concern in many countries. In the developing countries, swine wastewater is not properly collected and treated, the wastewater from swine farm pollutes the ecosystem. Especially for small swine farms, they could not afford to have wastewater treatment system. Therefore, farmers need cheap, sustainable technology for future mixed farming. Vermifiltration by earthworm has been introduced to be an answer for enhancing wastewater treatment. Vermiwash is the liquid gathered from vermicomposting that has high microbial activities and nutrients. This study was carried out on a small pilot scale to investigate swine wastewater treatment efficiency of vermifiltration system with and without vermiwash and compared with the geofiltration system. Vermiwash was incubated in vermifiltration and geofiltration systems for 1week before the treatment. The result showed improved efficiency of vermifiltration incubated with vermiwash in swine wastewater treatment for biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS) removal, which was highest followed by vermifiltration without incubated vermiwash, geofilter incubated with vermiwash and geofilter, respectively. Good performance of vermifiltration incubated with vermiwash compared with the geofilter treatment was demonstrated for removal of BOD (91.29 ± 9.89%, n = 10), COD (91.42 ± 6.34%, n = 10) and TSS (86.02 ± 10.45%, n = 10). Furthermore, the burrowing activity of the test earthworm (Eisenia fetida) promoted the aeration condition in vermifilter which led to more dissolved oxygen (DO) in effluent (61.28 ± 20.05%, n = 10). Moreover, the amount of copper (Cu) in effluent was decreased compared with influent by up to 88% in all treatment. After 10weeks of the experiment, the vermicompost that was incubated with vermiwash and produced from earthworm on the top layer was analyzed and showed that nutrients (nitrogen, phosphorus) and soil organic carbon were increased with vermifilter treatment (47.65, 81.61 and 31.79%, respectively) compared with geofilter treatment. In addition, bioavailability of Cu in soil in form of exchangeable Cu was decreased by increasing the bound to organic matter fraction. Transformation of Cu during vermifiltration happened and alleviated the mobility and availability of Cu. Copper in exchangeable form can change into non-toxic form. Therefore, vermifiltration process incubated with vermiwash could reduce the dispersion of copper in swine waste. In conclusion, vermiwash could enhance performance of vermifiltration for swine farm wastewater treatment. The available fraction of copper in vermicompost produced from vermifiltration decreased. Therefore, the farmer could produce vermicompost as the biofertilizer for agricultural production. Using vermifiltration for wastewater treatment in small swine farm could be the eco-solution for nutrient recovery, water resource recycles and minimize pollution.

Simple colorimetric ammonium assay employing well microplate with gas pervaporation and diffusion for natural indicator immobilized paper sensor via smartphone detection

A simple and cost-effective analytical device based on gas pervaporation and diffusion method for determination of ammonia is proposed. The proposed device is consisted of a well microplate as a donor chamber and a natural indicator-immobilized paper (butterfly pea flower extract) as an acceptor sensor. This allows microliter-scale solution handling. The sample preparation step involved conversion of ammonium ion to ammonia using an alkaline solution, following by gas pervaporation and then diffusion of ammonia across a PTFE membrane into a natural indicator-immobilized paper. The colorimetric change on the paper then was detected by either a smart phone camera or naked eye for quantitative or semi-quantitative analysis, respectively. Under the optimal condition, a linear calibration with a range of 10–100 mg/L ammonium-nitrogen was obtained. The method has a detection limit (3σ) of 4 mg/L ammonium-nitrogen, n = 9. This proposed device was successfully applied for determination of ammonia in swine farming wastewater and chemical fertilizer samples. It could simultaneously perform triplicate run of 18 samples in 15 min (72 samples/hr). The proposed device with pervaporation and diffusion method offers on-site assay and green chemical analysis with relatively high throughput.

Wastewater from swine farming in the growth and nutrition of Khaya senegalensis (DESR.) A Juss seedlings

This study evaluated the use of wastewater from swine farming in the growth and nutritional balance of Khaya senegalensis (Desr.) A. Juss. (African mahogany) seedlings. The experiment was setup in a shade house on the Professor Cinobelina Elvas Campus of the Federal University of Piauí, in Bom Jesus, in the State of Piauí, Brazil. The experimental design was completely randomised, with five concentrations of swine farm wastewater (SFW) (0, 25, 50, 75 and 100%) added to the irrigation water. The growth and nutritional balance of the seedlings were evaluated 100 days after sowing, by measuring shoot height (H), stem diameter (SD), number of leaves (NL), total chlorophyll (TC), leaf area (LA), shoot dry weight (SDW) and root dry weight (RDW), and by calculating the total dry weight (TDW), leaf (LBA), stem (SBA), and root (RBA) biomass allocation, Dickson Quality Index (DQI) and average Nutritional Balance Index (NBIm). It was found that K. senegalensis seedlings responded to the SFW, showing the best results for growth and nutritional balance at concentrations of around 50%.

Swine farm wastewater discharge causes masculinization of western mosquitofish (Gambusia affinis)

Natural and synthetic steroid hormones have been detected in swine farm wastewaters (SFWs) and receiving waters. However, little is known on their potential endocrine disrupting effects on fish population in receiving rivers. Here we investigated the concentrations of androgens and estrogens in the SFWs and the receiving waters. In addition, the endocrine disrupting effects of SFWs on wild western mosquitofish (Gambusia affinis) were also analyzed by assessing the sex ratio, secondary sex characteristics and transcriptional expression of genes related to the endocrine system. Chemical analysis showed the maximum concentration of total androgens reached 1375.7 ng L−1 in the SFWs and 1020.8 ng L−1 in receiving river waters. A total of 3552 adult G. affinis were collected from the Lianhe River (Guangdong, China), which was heavily impacted by SFWs, before and after the Ban of Swine Farming (BSF) in the river basin. The results showed the presence of male-biased G. affinis populations and masculinized anal fins and hemal spines of females at all contaminated sites prior to BSF. In addition, the transcription of vitellogenin (vtg) was inhibited by SFWs by 99.9% in the females from one sampling site. In contrast, the adverse effects on the females were significantly decreased after BSF. Redundant and path analyses showed that skewed sex ratios of fish populations, masculinized secondary sex characteristics of females and the decrease of vtg transcripts of females were well correlated with the concentrations of androgens in the receiving waters. The findings from this study suggest that SFW can cause masculinization effects of wild G. affinis populations.

Occurrence, fate and mass loadings of antibiotics in two swine wastewater treatment systems

Antibiotics are widely applied in livestock industry to prevent or treat animal diseases. However, those antibiotics are poorly metabolized in livestock animals, most of them being excreted via feces or urine. Hence we need to understand the removal of antibiotics in swine farm wastewater treatment systems. This study investigated occurrence and fate of various antibiotics in two full-scale swine farm wastewater treatment systems (Farm A: anaerobic digester-A2/O-lagoon; Farm B: upflow anaerobic sludge blanket (UASB)-(A/O)2-lagoon). The results showed the presence of 25 antibiotics out of 40 target antibiotics in the wastewater and sludge samples from the two farms. In Farm A, sulfamonomethoxine, sulfachlorpyridazine, oxytetracycline and lincomycin were predominant in the influent with concentrations up to 166 ± 3.64 μg/L, while in the dewatered sludge chlortetracycline, oxytetracycline, tetracycline and norfloxacin were the predominant target compounds with concentrations up to 29.2 ± 3.74 μg/g. In Farm B, high concentrations (up to 3630 ± 1040 μg/L) of sulfachlorpyridazine, sulfamonomethoxine and lincomycin were detected in the influent, and the predominant target antibiotics detected in the dewater sludge were similar to those in Farm A, with concentrations up to 28.6 ± 0.592 μg/g. The aqueous removal rates for the total antibiotics were >99.0% in the wastewater treatment plants of both farms. Among a series of treatment units, the anaerobic digester in Farm A and UASB in Farm B made a significant contribution to the elimination of the target antibiotics from the animal wastewater. The daily mass loadings of total antibiotics in the manure, influent, dewatered sludge and effluent were 17.1, 28.0, 2.53, and 0.0730 g/d for Farm A and 24.5, 354, 3.17, and 0.293 g/d for Farm B. The full-scale swine wastewater treatment facilities could effectively remove antibiotics from swine wastewater, but the dewatered sludge needs to be further treated before disposal on land.

Utilization of wastewater on seed germination and physioogical parameters of rice (Oryza sativa L.)

Due to increasing world population and demand, fresh water availability is becoming a limited resource. Reusing wastewater for agriculture has received attention since it contains nutrients, which are beneficial for growing crops. Even though wastewater can be used as the nutrient source for the plant, the toxicity of wastewater can still be a cause for concern and investigation. The main objective of this paper was to assess the effect of different sources of wastewater on the germination of Jasmine rice (KDML105), White rice (Phatum Thani 1), and Sticky rice (RD6) under laboratory conditions. Petri dish cultures were used with various concentrations (0, 50, and 100%) of wastewater collected from swine farm, aquaculture activity, and domestic. Seed germination, root length, shoot length, seed vigor index, fresh weight and dry weight were measured after each experiment. The results have shown that domestic wastewater and aquaculture activity wastewater did not decrease performance of Jasmine rice (KDML105), White rice (Phatum thani 1), and Sticky rice (RD6) while the germination of Jasmine rice (KDML105), White rice (Phatum thani 1), and Sticky rice (RD6) decreased when irrigated with swine farm wastewater. Therefore, using domestic and aquaculture activity wastewater for irrigation are suitable for growth of these crop.

Water quality degradation and management strategies for swine and rice farming wastewater in the tha Chin River Basin

Water quality in the Tha Chin River regularly exceeds biological oxygen demand (BOD) standards of Thailand’s Enhancement and Conservation of National Environmental Quality Act. This study quantified the BOD loading from rice cultivation and swine farming to the Tha Chin River using effluent data and procedures from the Pollution Control Department (PCD), geospatial land-use maps from the Land Development Department, and water quality data from the Ministry of Natural Resources and the Environment. It was determined that the BOD loading was 12 tons/day from swine farming in 2015 and 52 tons/day, on average, from rice farming between 2002 and 2011. Technology-specific, community-scale wastewater management strategies were recommended for both industries: feasibility studies revealed 66 potential sites for constructed wetland implementation and 7 subdistricts suitable for biogas network pipelines. It was determined that if these projects are implemented in conjunction, the BOD would be reduced by 6% (0.3 mg/L) in the entire river or 11% (0.5 mg/L) at the three water quality monitoring stations proximate to swine farms. These reductions would have a substantial effect on the water quality of the Tha Chin River, and governmental agencies such as the PCD should strongly consider subsidization and implementation of these projects.

Ligno-cellulosic materials as air-water separators in low-tech microbial fuel cells for nutrients recovery

Low-cost materials and low-tech architectures could give competitive advantage in scaling-up applications of microbial fuel cells (MFC), especially for nutrients recovery from wastewater. Here a novel concept is presented, based on cylindrical ligno-cellulosic materials, available as agricultural residues or spontaneous vegetation. Giant canes (Arundo Donax L.) and maize (Zea Mays) stalks were used as porous separators (naturally tubular) for air-cathode MFC modules (GC-MFC and MS-MFC, meaning Giant Cane and Maize Stalk, respectively), with carbon cloth-based electrodes. The MFCs were operated across 100 Ω external load, enriching swine-farming wastewater with addition of sodium acetate (3 g L−1). Initially, these systems showed relatively high internal resistances (especially GC, with Rint = 5600 Ω), before the material was completely imbibed by the anolyte. After 10–20 days acclimation, despite sufficient electrolytic conductivity was established in both systems (internal resistance around 60–90 Ω), relatively low power densities (around 40 mW m−2, normalized by cathode's surface projection) were achieved, if compared to state-of-the-art MFCs, oriented to electricity harvesting. However, the generated electric field was enough to sustain electro-osmotic ions mobility and to establish high pH conditions (pH 11–12) at the cathode. Over 70 days of operation, electro-migration and deposition phenomena of valuable elements (Na, Ca, Mg, Mn, K, etc.) were observed, both inside the separator and on the cathode surface. Simultaneously, partial biodegradation of the ligno-cellulosic biomass, especially for MS, drove partial release of organic carbon, nitrogen, phosphorous and other elements in the anodic chamber. These relevant phenomena have to be taken into account in view of possible applications of ligno-cellulosic materials in MFC-driven nutrients recovery from wastewater.

Swine Farm Wastewater Treatment by Constructed Wetland Planted with Vetiver Grass

This research investigated the pollutant removal efficiencies in swine farm wastewater with Vetiveria zizanioides (L.) Nash (Sri Lanka ecotype) in a surface flow constructed wetland (SFCW). The SFCW units were set up to 3 treatments at 10, 15 and 30 cm water levels to find the proper depth for vetiver grass in wastewater treatment. The water quality indicator such as pH, temperature (T), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total kjeldahl nitrogen (TKN), total phosphorus (TP) and heavy metals (Cu, Fe, Pb, Zn) were analyzed and compared with terms of removal efficiency. The 30 cm water depth has a better removal efficiency of organic substance treatment (BOD and COD). The BOD, COD, TKN and TP removal efficiency had no statistically significant differences between the water depths. TP has the best removal efficiency with average 95.18-96.53%. The treatment of heavy metals such as Cu, Pb, Fe and Zn with vetiver grass in different water depths was showed no statistical significance since it can reduce only a small number of these metals. However, the results showed that the effluent from all the treatment units contained averages of BOD, COD, TKN and pH that followed Thailand’s swine wastewater quality standard.

Assisting cultivation of photosynthetic microorganisms by microbial fuel cells to enhance nutrients recovery from wastewater

Spirulina was cultivated in cathodic compartments of photo-microbial fuel cells (P-MFC). Anodic compartments were fed with swine-farming wastewater, enriched with sodium acetate (2.34gCODL−1). Photosynthetic oxygen generation rates were sufficient to sustain cathodic oxygen reduction, significantly improving P-MFC electrochemical performances, as compared to water-cathode control experiments. Power densities (0.8–1Wm−2) approached those of air-cathode MFCs, run as control. COD was efficiently removed and only negligible fractions leaked to the cathodic chamber. Spirulina growth rates were comparable to those of control (MFC-free) cultures, while pH was significantly (0.5–1unit) higher in P-MFCs, due to cathodic reactions. Alkaliphilic photosynthetic microorganisms like Spirulina might take advantage of these selective conditions. Electro-migration along with diffusion to the cathodic compartment concurred for the recovery of most nutrients. Only P and Mg were retained in the anodic chamber. A deeper look into electro-osmotic mechanisms should be addressed in future studies.

Using swine farming wastewater for Signal grass cultivation

The objective of this study was to evaluate forage production and root accumulation in Brachiaria decumbens cv. Basilisk with swine wastewater as a fertilizer. The experiment was conducted into a greenhouse in Federal Institute of Education, Science and Technology of Southeast of Minas Gerais, Rio Pomba Campus. Pots with 6 dm-3 volumes were used as experimental units. Were used a randomized block design with four replications. Were studied four swine waste doses (0, 225, 450 and 675mL pot-1) over four regrowth cycles. The dry matter production of the aerial part, forage accumulation rate, crude protein and dry matter production of roots increased with the highest swine waste doses being around 670, 742, 160 and 465% respectively from lower to higher dose. There was interaction between swine waste and regrowth cycles for plant height and tillering, and in all regrowth cycles responded positively with increasing swine waste doses. Applying swine waste on pastures is therefore a viable alternative to increase productivity of B. decumbens cv. Basilisk, it recommends the use of swine waste corresponding to the dose of 675mL pot-1 to maintenance pastures