Animal Wastewater Research Articles

Rapid Hydrolysis of Penicillin Antibiotics Mediated by Adsorbed Zinc on Goethite Surfaces.

The soil environment is an important sink for penicillin antibiotics released from animal manure and wastewater, but the mineral-catalyzed transformation of penicillins in soil has not been well studied. To simulate this environmental process, we systematically investigated the behavior of penicillin G and amoxicillin, the two most widely-used penicillin antibiotics, in the presence of goethite and metal ions. The results demonstrated that Zn ions significantly promoted the hydrolysis of penicillins in goethite suspensions, as evidenced by the degradation rate nearly 3 orders of magnitude higher than that of the non-Zn-containing control. The spectroscopic analysis indicated that the specific complexation between penicillins, adsorbed Zn, and goethite was responsible for the enhanced degradation. Metastable interactions, involving hydrogen bonds between carbonyl groups in the β-lactam ring and the double/triple hydroxyl groups on goethite surface, and coordination bonding between carboxyl groups and surface irons were proposed to stabilize the ternary reaction intermediates. Moreover, the surface zinc-hydroxide might act as powerful nucleophile to rapidly rupture the β-lactam ring in penicillins. This study is among the first to identify the synergic roles of Zn ion and goethite in facilitating penicillin degradation and provides insights into β-lactam antibiotics to assess their environmental risk in soil.

Treatment of High-Strength Animal Industrial Wastewater Using Photo-Assisted Fenton Oxidation Coupled to Photocatalytic Technology

Animal wastewater is one of the wastewaters that has a color and is difficult to treat because it contains a large amount of non-degradable organic materials. The photo-assisted Fenton oxidation technique was applied to treat animal wastewater, and the optimal conditions of chemical oxygen demands (COD) removal were analyzed according to changes in pH, ferrous ion, H2O2, and ultraviolet (UV) light intensity as a single experimental condition. Experimental results showed that, under the single-factor experimental conditions, the optimal conditions for degradation of animal wastewater were pH 3.5, Fe(II) 0.01 M, H2O2 0.1 M, light intensity 3.524 mW/m2. Under the optimal conditions, COD removal efficiency was 91%, sludge production was 2.5 mL from 100 mL of solution, color removal efficiency was 80%, and coliform removal efficiency was 99.5%.

Phosphorus recovery by ion exchange in a solid carbonate: modeling of the process.

Phosphorus (P) is a nutrient for plant growth but also a pollutant in water bodies causing eutrophication. The source of P is mainly human and animal wastewater and runoffs from different land uses. The objective of the present study is to evaluate P removal and recovery processes by ion exchange (IE) with solid carbonate (SC) in biodigestor-treated swine effluent (BTSE) using hydrogeochemical modeling. For this, BTSE compositions were obtained by literature review. A synthetized and characterized SC was used and the ion exchange site concentration ([SC-IE]) and the IE constants (Kie) were obtained experimentally and applied to model P and major anion removal and recovery processes. P recovery was evaluated for different BTSE compositions and several concentrations of SC, dissolved P (HPO42-), competing anions such as SO42-, and CO32-. The simulations suggest that a [SC-IE]:[HPO4] of 1.4 molar ratio would allow the recovery of 90% of HPO4 in BTSE, and at average alkalinity concentrations in BTSE, CO32- would compete with HPO4 for the SC-IE. The P recovery by the SC-IE process was compared with two other methods commonly used in P removal from BTSE: removal with aluminum sulfate and precipitation of struvite as a function of pH. The results suggest that SC-IE is the most efficient method in the pH range of BTSE. Besides, HPO42- was readily recovered as inorganic P that may be reused in agriculture and industrial processes.

Bacterial indicator reduction in dairy manure using hybrid zero-valent iron (h-ZVI) system.

Novel and efficient animal wastewater treatment technologies of bacteria reduction are needed for preventing disease outbreak in animal herds and safeguarding environmental health. Zero-valent iron (ZVI) has been used to treat bacteria contaminated water for the past decades, but its passivation issue has been a major challenge. In this study, batch tests were performed to evaluate the effect of a hybrid zero-valent iron (h-ZVI) or a mixed ZVI/Fe3O4 media system on reduction of Escherichia coli (E. coli) levels. The h-ZVI media was created through a wet chemical process that uses nitrate to oxidize ZVI in the presence of externally added Fe2+ (aq.). Transforming ZVI into a h-ZVI system could overcome the passivation of ZVI and increase the reactivity of the media. The results demonstrated that E. coli cells in the bulk phase were removed rapidly by h-ZVI media. Majority of E. coli was attached (or adsorbed) to the surface of h-ZVI media within a few minutes, which suggested that adsorption was the dominant mechanism for bacterial removal in the initial phase. This adsorption was confirmed by fluorescence microscopy with CTC-DAPI double staining and transmission electron microscopy (TEM). Increasing contact time steadily inactivated E. coli; all cells were inactivated after 120min of contact. The TEM results indicated that h-ZVI inactivated E. coli by causing direct damage on bacterial cell membrane. The results of this study strongly suggest that h-ZVI treatment can be used in water treatment industry where bacterial contamination is concerned.

Biogas to methanol: A comparison of conversion processes involving direct carbon dioxide hydrogenation and via reverse water gas shift reaction

Methanol is a clean fuel and an important intermediate in chemical synthesis. In this work, the synthesis of methanol from a large-scale biogas plant utilizing biomass in the form of animal, food and dairy wastes and wastewater sludge is studied. It considers upgrading the biogas into biomethane through a separation step to remove CO2 prior to steam reforming and produces syngas for methanol synthesis. Instead of rejecting to the atmosphere, the separated CO2 is mixed with the syngas from the reformer and fed to the methanol reactor. Three process schemes are simulated (using two different catalysts) and compared on the basis of maximum CH4 conversion and methanol productivity. While one of the catalysts is a conventional catalyst preferred for a CO-rich syngas feed, the second catalyst is designed for direct hydrogenation of a CO2-rich syngas feed. The process alternatives use reverse water gas shift reaction, direct CO2 hydrogenation and intermediate water removal. From the different cases considered, the maximum possible methanol production is 2100 tons per day from a biogas feed of 1.8 × 106 Nm3/year – this corresponds to a process of steam methane reforming followed by direct CO2 hydrogenation using Cu/Zn/Al/Zr catalyst (two methanol reactors in series with intermediate water removal between them.) It was also shown that all the three processes can be designed to be self-sufficient in meeting their electricity requirements without the use of any external fuel like natural gas, etc. Since we are converting waste to energy utilizing biomass and don't require any additional fossil fuels, this can be referred to as a clean and green production process.

Microbial Cycling of Methanethiol.

Methanethiol (MT) is an organic sulfur compound with a strong and disagreeable odour. It has biogeochemical relevance as an important compound in the global sulfur cycle, where it is produced as a reactive intermediate in a number of different pathways for synthesis and degradation of other globally significant sulfur compounds such as dimethylsulfoniopropionate, dimethylsulfide and methionine. With its low odour threshold and unpleasant smell, MT can be a significant cause of malodour originating from animal husbandry, composting, landfill operations, and wastewater treatment and is also associated with faeces, flatus and oral malodour (halitosis). A diverse range of microorganisms drives the production and degradation of MT, including its aerobic and anaerobic metabolism. MT producing and degrading organisms are known to be present in terrestrial, freshwater and marine environments but may also be important in association with plant and animal (including human) hosts. This chapter considers the role of MT as an intermediate of the global sulfur cycle and discusses current knowledge of microbial pathways of MT production and degradation.

Exploring the sensitivity of nanodiamond to sarafloxacin: A DFT approach

Increase in antibiotics applications in animal industry leads to an environmental risk due to remaining of these compounds and their derivatives in animal production, wastewaters and soils. This study investigates the sensitivity of nanodiamond to sarafloxacin to detect a widely used antibiotic in poultry industry. The interaction between hydrogen terminated nanodiamond and sarafloxacin was studied for four different configurations of the conjugated system by density functional theory and then, adsorption energy and HOMO-LUMO gap energy of the conjugated systems were calculated. The results revealed that the sarafloxacin can be physically adsorbed on hydrogen terminated nanodiamond. The physical adsorption through the weak to medium non-covalent strength interactions has received the most attention in sensing applications; therefore, nanodiamond can be a possible candidate for nanobiosensor investigations.

Characterization of airborne antibiotic resistance genes from typical bioaerosol emission sources in the urban environment using metagenomic approach

The wide spread of antibiotic resistance genes (ARGs) has attracted increasing concern. However, the occurrence and diversity of ARGs in airborne particles remains to be understood. In this study, total suspended particles (TSP) in the atmosphere were collected from typical sources of ARG pollution, including animal farms and wastewater treatment plant (WWTP), as well as the downtown area in Zhuhai, China. Metagenomic profiling demonstrated that ARGs were abundant and diverse in the TSP from animal farms and WWTP, but significant differences in ARG composition pattern between these samples were observed. ARGs associated with the resistance to aminoglycoside, macrolide-lincosamide-streptogramin (MLS) and tetracycline were dominant over other ARGs in the TSP of the animal farms, whereas multidrug and bacitracin resistance genes were more abundant than other ARGs in the TSP of the WWTP. In the animal farms, ARG profiles of the TSP were consistent with those of animal feces, indicating that animal feces could be one of the most contributing sources of airborne ARGs in animal farms. In contrast to representative sources of ARG pollution, ARG abundance and diversity in the TSP collected from the downtown area was relatively low, with multidrug resistance genes being predominant. This study suggests that metagenomic profiling of the ARGs in airborne TSP could enhance our comprehensive understanding of ARGs dissemination in the environment and their potential health threats.

Systematic analysis of occurrence and variation tendency about 58 typical veterinary antibiotics during animal wastewater disposal processes in Tianjin, China

Residue of veterinary antibiotics (VAs) in the animal breeding industry has become a problematic environmental issue. However, the residual levels of VAs as well as their variation tendency, degradation mechanisms and relationships with other parameters during animal wastewater disposal processes are still obscure. This study measured different samples during wastewater disposal processes from three farms, and systematically analyzed the residue, migration and removal of 58 kinds of typical VAs (6 classes) in Tianjin, China. The results showed that about 44 kinds of VAs were quantitatively detected. Tetracycline antibiotics (TCs) usually had higher residual concentrations than other classes of VAs in the raw wastewater; the highest residual concentration was 130.67 ± 5.90 μg/L which occurred for chlortetracycline (CTC). Pig farms generally had more VAs species and higher residual concentrations than dairy farms, and the proportion of different VAs was similar for dairy farms. The final removal rates of different VAs classes varied largely (negative to > 99.87%), and the highest removal rates usually occurred in biological processes for adsorption and biodegradation effects, and occasionally occurred in the final effluents. The correlation coefficients between VAs removal rates and chemical oxygen demand (COD) removal rates were much higher than those of total nitrogen (TN), total phosphorus (TP) and ammonia nitrogen (NH4-N) in pig farms, while opposite conclusion was obtained in dairy farms. Among different classes, TCs presented the highest daily mass loading of ND ~ 10,453.8 ± 471.7 mg/d in the influent and ND ~ 1141.6 ± 58.9 mg/d in the effluent in farm 1.

Electrodisinfection of real swine wastewater for water reuse

Swine production generates large volumes of wastewater, rich in organic matter, nutrients and pathogens. Electrodisinfection is used to remove organic matter and nutrients from animal wastewater, but its effectiveness on pathogens inactivation has not been studied using real swine wastewater. Therefore, we evaluated the efficiency of electrodisinfection on pathogens reduction using real swine wastewater. For that, we tested the effect of pH and current density, using iron and aluminum electrodes. Results show a 99.99% reduction of Escherichia coli when electrodisinfection was performed during 60 min at pH 3.0 and current density of 44 mA cm−2 using iron or aluminum electrodes. The liquid fraction obtained after electrodisinfection can be reused for cleaning swine buildings, thus avoiding the use of potable water.

The Potency Of Livestock Waste Into Renewable Energy (Biogas) In Palipu District Tana Toraja Regency

The utilization of renewable energy sources are derived from non-fossil sources such as urban waste, animal manure, agricultural waste and other biomass sources are becoming increasingly important. Biogas is a renewable energy source produced by anaerobic fermentation of organic material. Biogas can be produced from animal manure, wastewater, and solid waste. Its composition varies, depending on the source material biogas Biogas is a renewable energy and fuel used to replace fossil such as kerosene and natural gas. This study aims to find out how much the production of biogas in the third installation of biogas reactor 4 m3 in the village of Tana Toraja Palipu. The research method with survey variants directly measure pH, temperature, and the production of biogas. The results showed pH of 6,49 input materials, output of 7.8, the temperature in the reactor an average of 29°C, ambient temperature Average at 26°C, biogas production average of 2,714 m3 per day. The potential of 1 kg of livestock waste to produce 0.117 m3 of biogas. In Palipu District the are 2561 pigs (data of Jun 2017) producing an average of 1 kg waste / day for a total of 2561 kg of waste per day. The potential of livestock waste in Palipu District of 2561 kg waste x 0,117 m3 = 299,637 m3, of biogas, equivalent to Liquit Petrolium Gas (LPG) 299,637 m3 x 0,06 kg, Kerosene 299,637 x 0,6 = 185,770 liters, Solar Oil 299,637 x 0,52=155,811 liters, Fire wood 299,637 x 0,35 = 1048,73 kg.

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.

Environmentally sustainable applications of agro-based spent mushroom substrate (SMS): an overview

Agricultural wastes such as lignocellulosic residues are renewable resources can be used for mushroom cultivation. Spent mushroom substrate (SMS) is defined as leftover of biomass generated by commercial mushroom industries after harvesting period of mushroom. Mushroom cultivation using agricultural wastes promises a good quality of SMS for producing beneficial products such as animal feeding and fertilizers. Based on the published papers, the major applications of SMS are animal feedstock, fertilizer, energy production and wastewater treatment. For instance, some species of mushroom such as Pleurotus spp. and Agaricus bisporus are suitable for applications of ruminant feedstock and fertilizers. This paper reviews the recent studies about the beneficial usage of SMS which is considered as a waste since 2013.

Simultaneous electricity production and antibiotics removal by microbial fuel cells

The removal of antibiotics is crucial for improvement of water quality in animal wastewater treatment. In this paper, the performance of microbial fuel cell (MFC) in terms of degradation of typical antibiotics was investigated. Electricity was successfully produced by using sludge supernatant mixtures and synthesized animal wastewater as inoculation in MFC. Results demonstrated that the stable voltage, the maximum power density and internal resistance of anaerobic self-electrolysis (ASE) −112 and ASE-116 without antibiotics addition were 0.574 V, 5.78 W m−3 and 28.06 Ω, and 0.565 V, 5.82 W m−3 and 29.38 Ω, respectively. Moreover, when adding aureomycin, sulfadimidine, roxithromycin and norfloxacin into the reactors, the performance of MFC was inhibited (0.51 V–0.41 V), while the output voltage was improved with the decreased concentration of antibiotics. However, the removal efficiency of ammonia nitrogen (NH3-N) and total phosphorus (TP) were both obviously enhanced. Simultaneously, LC-MS analysis showed that the removal efficiency of aureomycin, roxithromycin and norfloxacin were all 100% and the removal efficiency of sulfadimidine also reached 99.9%. These results indicated that antibiotics displayed significantly inhibitions for electricity performance but improved the quality of water simultaneously.

Una Comparación de Rendimiento entre Dos Configuraciones de Biodigestores Anaerobios para la Producción de Biogás

La comparación del rendimiento se hizo para las dos configuraciones de biodigestores comunes existentes a la fecha el tanque continuamente (CSTBR) y el de flujo a pistón (PFBR), para producir biogás y electricidad mediante digestión anaerobia utilizando como sustrato desechos industriales de granjas de leche para su aplicación en áreas rurales, de Latinoamérica y poder general energía renovable como la electricidad y fertilizante líquido, a la vez reducir la contaminación de las aguas residuales, gases de efecto invernadero, y el olor. Dos sistemas de configuración CSTBR y PFBR fueron instalados a escala de laboratorio utilizando como sustrato desechos de lechería. Los resultados muestran que bajo las mismas condiciones de operación HRT 1 día y OLR 19.4 g DQO/L día el CSTBR produce más biogás (1.0 L/L d), metano (0.8 L/L d) que el PFBR cuyos valores correspondientes fueron biogás (0.8 L/L d), metano (0.6 L/L d), y remoción de materia orgánica 12% COD, 8.7% VS que los obtenidos en el PFBR, 11.5% COD, 8.1% VS. El rendimiento fue el mismo cuando el HRT fue incrementado a 3 días y el OLR disminuido a 9.8 g DQO/L dia. La comunidad microbiana entre las configuraciones CSTBR and PFBR fueron realizadas usando la técnica de pirosecuenciación. Las comunidades microbianas son variables con una distribución y abundancia de grupos taxonómicos diferentes entre las muestras de los sistemas de configuraciones, una mayor riqueza de diversidad microbiana de archaeal se encontró en la muestra del PFBR mientras que una mayor diversidad de bacterias se encontró en la muestra del CSTBR. Se recomienda aplicar la configuración CSTBR para la DA. Sin embargo, la configuración PFBR puede ser mejorada aplicando agitación intermitente, que fallan debido a la colmatación de solidos debido a los altos valores de HRT y SRT, especialmente para biodigestores PFBR a pequeña escala instalados en países en desarrollo.

Fate of estrone in laboratory-scale constructed wetlands

A horizontal, subsurface, laboratory-scale constructed wetland (CW) consisting of four cells in series was used to determine the attenuation of the steroid hormone estrone (E1) present in animal wastewater. Liquid swine manure diluted 1:80 with farm pond water and dosed with [14C]E1 flowed through the series of cells containing floating vegetation (duckweed, family Lemnaceae) and a sand:gravel sediment layer. The aqueous layer within each cell was sampled across time, and at 168h duckweed and sediment were sampled for E1 and/or its metabolites. Control and Blank systems consisted of single cells with no vegetation or no vegetation/sediment, respectively. Only 5% of the dose was detected in the effluent at 168h. With the use of mass spectrometry and thin layer chromatography, it was determined that E1 was metabolized into estriol (E3) and to polar metabolites. The largest compartment for [14C] was duckweed (42.1% of administered dose) at 168h followed by sediment (17.3%) and the liquid layer (15.1% of the dose). Most of the vegetative removal of E1 occurred in the first cell, and thereafter, sediment:liquid layer interactions governed E1 movement suggesting particle-bound transport on either colloids or dissolved organic matter. Horizontal, subsurface flow CW were able to remove approximately 95% of the influent E1, and demonstrated the importance of vegetative matter in removal of this potent steroid hormone.

Determination of crAssphage in water samples and applicability for tracking human faecal pollution.

SummaryIn recent decades, considerable effort has been devoted to finding microbial source‐tracking (MST) markers that are suitable to assess the health risks of faecally polluted waters, with no universal marker reported so far. In this study, the abundance and prevalence of a crAssphage‐derived DNA marker in wastewaters of human and animal origins were studied by a new qPCR assay with the ultimate aim of assessing its potential as an MST marker. crAssphage showed up to 106 GC/ml in the sewage samples of human origin, in both the total DNA and the viral DNA fraction. In wastewaters containing animal faecal remains, 39% of the samples were negative for the presence of the crAssphage sequence, while those showing positive results (41% of the samples) were at least 1 log10 unit lower than the samples of human origin. Noteworthy, the log10 values of the ratio (R) crAssphage (GC/ml)/Escherichia coli (CFU/ml) varied significantly depending on the human or animal origin (R > 1.5 for human samples and R < −1.5 for animal wastewater samples. This study opens the way for further research to explore if different specific animal variants of crAssphage exist and whether other zones of the crAssphage genome are better suited to source discrimination.

Direct Conversion Fuel Cell of Urine in Animal Wastes and Its Condition Monitoring Sensors for Efficient Water Usage in Agriculture

Over one billion tons of agricultural (e.g. manure), municipal (e.g. biosolids), and industrial (e.g. coal combustion products) wastes with potential uses in agriculture are generated annually in the United States according to the National Agricultural Statistics Service [1]. An annual global production of about 40 billion liters of urine from farm animals is estimated. If urine by humans is added to that figure, 6.5 trillion liters are produced every year. Many of these materials are spread, sprayed or otherwise applied to agricultural land because of the benefits they provide. These benefits include: providing a nutrient source for crops; improving soil chemical, physical and biological properties; improving soil water storage and use; reducing movement of contaminants to water and air; and reducing production costs and energy use. However, improperly managed manure and other byproducts can pose a threat to soil, water and air quality, and to human and animal health. To prevent environmental pollution, it is important to treat them before release with minimal power consumption. For example, in activated sludge process, which is conventional wastewater treatment process, 1kWh/kg carbohydrate of energy is required [2]. If we can recover and use it for wastewater treatment, total power consumption for wastewater treatment will be reduced, and further, if the amount of recovered energy exceeds the amount of required energy for wastewater treatment, energy can be obtained from wastewater. In this project, we demonstrates very efficient and scalable direct urine fuel cells without the use of bacteria to mitigate animal waste, as well as generate electricity from wastewater. Unlike common microbial fuel cells that use electrons produced by bacterial metabolism [3], the proposed fuel cell is to harvest electrons directly from urea in urine by converting urea into H2O, CO2 and N2. Newly engineered electrodes and electrolytes were developed for efficient and rapid electricity generation. Since the mechanisms relating to direct conversion of urea have still not been understood entirely, our condition monitoring sensors will be re-engineered to measure chemical species generated by reactions between animal wastewater and fuel cells. The performance of the fuel cell is enhanced by developing unique sensing probes to monitor conditions of the reactors and animal wastes. Electrochemical sensors based on hierarchically nanostructured functional metal oxides. The measurement of gas and liquid environment of animal waste is demonstrated by addressing sensitivity, sensitivity and response time.

Monitoring of Antibiotics in the Soil and Sediment Near at the Animal Feeding Operation and Wastewater Treatment Plant

Antibiotics have been used for treating human and animal disease and enhancing growth of cattle, swine, and poultries. However, overused antibiotics can be released into the environment and produce antibiotic resistance genes (ARGs) in the environment. Main objective of this research was to monitor residual of antibiotics in solid matrix such as manure, wastewater sludge, soil and sediment. Total of six antibiotics, Chlortetracycline (CTC), Oxytetracycline (OTC), Tetracycline (TC), Sulfamethazine (SMT), Sulfamethoxazole (SMX), Sulfathiazole (STZ), used for both human and animal was monitored. Result showed that the detection frequency of 6 antibiotics was ordered SMT (100%) > TC = CTC (75%) > OTC (38%) > STZ (13%) > SMZ (0%) and the highest concentration (309.83 μg kg-1, SMT) was observed in manure. Comparing residual concentration of antibiotics (TC, CTC, and OTC) in soil and sediment, higher concentration was observed in sediment indicating that dissolved forms of antibiotics are released into river and sorbed into sediment particle. In conclusion, monitoring for residual of antibiotics in the environment is necessary and more research should be conducted to verify the source of antibiotic release.Antibiotic residuals in soil, sediment, manure, and sludge and its transport in the environment.

Bioavailability of dissolved organic nitrogen (DON) in wastewaters from animal feedlots and storage lagoons

Dissolved organic nitrogen (DON) from animal wastes can contribute to pollution of surface waters. Bioavailable DON (ABDON) is a portion of DON utilized by algae with or without bacteria. This study determined DON and ABDON levels in animal wastewater collected from two different sources: an animal feedlot wastewater storage tank and a sheep wastewater storage lagoon. Inocula for the ABDON bioassays were comprised of individual species and several combinations involving two algae (Chlamydomonas reinhardtii and Chlorella vulgaris) and a mixed liquor suspended solids (MLSS) bacterial culture. The ratio of initial DON to initial total dissolved nitrogen was 18% in the feedlot wastewater samples and 70% in the lagoon wastewater samples. The results showed that between 1.6 and 4.5 mg-NL-1 DON (45–79% of initial DON) in the feedlot samples and between 3.4 and 7.5 mg-NL-1 DON (36%–79% of initial DON) in the lagoon samples were bioavailable with the inocula tested. These results suggest that when considering eutrophication potential of livestock wastewater, organic nitrogen should be included in addition to the obvious culprits, ammonia and nitrate.