Bioavailability of High Molecular Weight Polycyclic Aromatic Hydrocarbons Using Renewable Resources

Introduction: Polycyclic aromatic hydrocarbons (PAHs) are the world’s largest class of carcinogens known to date, not only because of their ability to cause gene mutation and cancer, but due to their persistency in the environment. They are particularly recalcitrant due to their molecular weight, hydrophobic nature and thus, accumulate in various matrices in the environment

Heterogeneous Fenton Degradation of Patulin in Apple Juice Using Carbon-Encapsulated Nano Zero-Valent Iron (CE-nZVI)

Patulin (PAT), a mycotoxin found mainly in matured apples, is produced by different species of fungi, mainly Penicillium expansum, and is found in various fruits and vegetables used to produce juice. Little focus has been placed on nano-technological methods for the mitigation of this problem. In this work, carbon-encapsulated nano-zero valent iron (CE-nZVI) particles were synthesized and used as heterogeneous Fenton agents for the degradation of PAT in apple juice. The particles were found to have a spherical shape with a diameter of 130 ± 50 nm. In a heterogeneous Fenton degradation (involving CE-nZVI) process, a concentration of 0.05 g/L CE-nZVI with 0.5 mM H2O2 was used. Since the Fenton oxidation process is pH-dependent, placebo degradation was observed at varying pH conditions with an average percentage of PAT degradation of 27.8%, 87.0%, 98.0%, and 99.75% at pH 6, 5, 4.5, and 3.5 respectively, between 1 min to 4 h in a water matrix. In a juice matrix, at the regular pH of juice (3.6), percentage PAT degradation of 72% and 89% was obtained after a 2-h treatment using heterogeneous Fenton oxidation (CE-nZVI/H2O2) systems, using 0.5 mM H2O2 and 1 mM H2O2, respectively.This work was supported by the institutions IUACA (University Institute of the Water and the Environmental Sciences) University of Alicante (UA). I would also like to thank the Beca del Convenio Fundacion Mujeres por África y Universidad de Alicante Vice-Rectorate Equality Program (UA) for funding Notemba Silwana

Treatment of Poultry Slaughterhouse Wastewater (PSW) Using a Pretreatment Stage, an Expanded Granular Sludge Bed Reactor (EGSB), and a Membrane Bioreactor (MBR)

This study presents the biological treatment of poultry slaughterhouse wastewater (PSW) using a combination of a biological pretreatment stage, an expanded granular sludge bed reactor (EGSB), and a membrane bioreactor (MBR) to treat PSW. This PSW treatment was geared toward reducing the concentration of contaminants present in the PSW to meet the City of Cape Town (CoCT) discharge standards and evaluate an alternative means of treating medium- to high-strength wastewater at low cost. The EGSB used in this study was operated under mesophilic conditions and at an organic loading rate (OLR) of 69 to 456 mg COD/L·h. The pretreatment stage of this laboratory-scale (lab-scale) plant played an important role in the pretreatment of the PSW, with removal percentages varying between 20% and 50% for total suspended solids (TSS), 20% and 70% for chemical oxygen demand (COD), and 50% and 83% for fats, oil, and grease (FOG). The EGSB further reduced the concentration of these contaminants to between 25% and 90% for TSS, 20% and 80% for COD, and 20% and >95% for FOG. The last stage of this process, i.e., the membrane bioreactor (MBR), contributed to a further decrease in the concentration of these contaminants with a peak removal performance of >95% for TSS and COD and 80% for the FOG. Overall, the system (pretreatment–EGSB–MBR) exceeded 97% for TSS and COD removal and 97.5% for FOG removal. These results culminated in a product (treated wastewater) meeting the discharge standards

Medicinal Plants Threatened by Undocumented Emerging Pollutants: The Sub-Saharan African Viewpoint

The history of medicinal plants on the African continent is huge, the oldest and probably the most diverse, for there are thousands of spoken languages, in the sub-Saharan African region, that are used during the traditional practices that utilize medicinal plants for healing purposes. However, our lines of research have exhibited a potential unprecedented threat to this remarkable history of African medicinal plants by emerging pollutants, the per- and polyfluoroalkyl substances (PFASs), which are yet to be efficiently and sufficiently reported and documented on in this region. Accordingly, this review chapter reports on sub-Saharan African medicinal plants with the aim of highlighting how undocumented PFASs, in this region, present a huge threat to the extraordinary diversity of these plants and the therapy that they have assisted the low-income populations of this region with for centuries. Thus, we recommend appropriate and regular assessments and monitoring of PFASs, particularly perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) the most studied of these substances and their substitutes, in medicinal plants of the region, for these chemicals have been scientifically proven to be associated to numerous health concerns. The region should also consider properly regulating these compounds

Assessment of an Integrated and Sustainable Multistage System for the Treatment of Poultry Slaughterhouse Wastewater

This paper assesses the performance of an integrated multistage laboratory-scale plant, for the treatment of poultry slaughterhouse wastewater (PSW). The system was comprised of an eco-flush dosed bio-physico pre-treatment unit for fats, oil, and grease (FOG) hydrolysis prior to the PSW being fed to a down-flow expanded granular bed reactor (DEGBR), coupled to a membrane bioreactor (DEGBR-MBR). The system’s configuration strategy was developed to achieve optimal PSW treatment by introducing the enzymatic pre-treatment unit for the lipid-rich influent (PSW) in order to treat FOG including odour causing constituents such as H2S known to sour anaerobic digestion (AD) such that the PSW pollutant load is alleviated prior to AD treatment. This was conducted to aid the reduction in clogging and sludge washout in the DEGBR-MBR systems and to achieve the optimum reactor and membrane system performance. A performance for the treatment of PSW after lipid reduction was conducted through a qualitative analysis by assessing the pre- and post-pre-treatment units’ chemical oxygen demand (COD), total suspended solids (TSS), and FOG concentrations across all other units and, in particular, the membrane units. Furthermore, a similar set-up and operating conditions in a comparative study was also performed. The pre-treatment unit’s biodelipidation abilities were characterised by a mean FOG removal of 80% and the TSS and COD removal reached 38 and 56%, respectively. The final acquired removal results on the DEGBR, at an OLR of ~18–45 g COD/L.d, was 87, 93, and 90% for COD, TSS, and FOG, respectively. The total removal efficiency across the pre-treatment-DEGBR-MBR units was 99% for COD, TSS, and FOG. Even at a high OLR, the pre-treatment-DEGBR-MBR train seemed a robust treatment strategy and achieved the effluent quality set requirements for effluent discharge in most countries

Poultry Slaughterhouse Wastewater Remediation Using a Bio-Delipidation Pre-Treatment Unit Coupled with an Expanded Granular Sludge Bed Reactor

The treatment of poultry slaughterhouse wastewater (PSW) with an Expanded Granular Sludge-Bed Bioreactor (EGSB) is hindered by the washout of activated sludge, and difficulties associated with the operation of the three-phase separator and the determination of the optimum up-flow velocity for sludge-bed fluidization. This results in a poor reactor functionality, and thus a poor performance due to pollutants such as fats, oil and grease (FOG) in the PSW being treated. Hydrolyzing the FOG content with a bio-delipidation, enzyme-based agent in a pre-treatment unit would significantly improve the effectiveness of the primary PSW treating system, i.e., the EGSB. In this study, PSW was pre-treated for 48 h with a biological mixture containing bioflocculants and bio-delipidation constituents. The pre-treated PSW was further treated in an EGSB. The PSW FOG, total chemical oxygen demand (tCOD) and total suspended solids (TSS) content were determined to assess the effectiveness of the pre-treatment process as well as to observe the remedial action of the combined pre-treatment-EGSB system. An increased treatment efficacy was noted for the combined PSW treatment system, whereby the tCOD, FOG and TSS removal averaged 76%, 88% and 87%, respectively. The process developed is intended for micro, small and medium poultry slaughterhouses

Multicapillary membrane bioreactor design

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2005The white rot fungus, Phanerochaete chrysosporium, produces enzymes, which are capable of degrading chemical pollutants. It was detennined that this fungus has multiple growth phases. The study provided infonnation that can be used to classify growth kinetic parameters, substrate mass transfer and liquid medium momentum transfer effects in continuous secondary metabolite production studies. P. chrysosporium strain BKMF 1767 (ATCC 24725) was grown at 37 QC in single fibre capillary membrane bioreactors (SFCMBR) made of glass. The SFCMBR systems with working volumes of 20.4 ml and active membrane length of 160 mm were positioned vertically. Dry biofilm density was determined by using a helium pycnometer. Biofilm differentiation was detennined by taking samples for image analysis, using a Scanning Electron Microscope at various phases of the biofilm growth. Substrate consumption was detennined by using relevant test kits to quantify the amount, which was consumed at different times, using a varying amount of spore concentrations. Growth kinetic constants were detennined by using the substrate consumption and the dry biofilm density model. Oxygen mass transfer parameters were determined by using the Clark type oxygen microsensors. Pressure transducers were used to measure the pressure, which was needed to model the liquid medium momentum transfer in the lumen of the polysulphone membranes. An attempt was made to measure the glucose mass transfer across the biofilm, which was made by using a hydrogen peroxide microsensor, but without success

A perfluorocarbon-based oxygen delivery system to a membrane bioreactor

Thesis submitted in fulfilment of the requirements for the degree DOCTOR TECHNOLOGIAE: ENGINEERING: CHEMICAL In the FACULTY OF ENGINEERING At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2009The white rot fungus, Phanerochaete chrysosporium strain BKMF-1767 (ATCC 24725), produces the extracellular enzymes, Lignin peroxidase (LiP) and Manganese peroxidase (MnP), that constitute the major route for lignin degradation by this organism. LiP and MnP have also been shown to play a major role in aromatic pollutant degradation. Due to the need for continuous production of LiP and MnP, a fixed-film bioreactor, classified as a membrane gradostat reactor (MGR), was developed. The implementation of batch-reactor operational parameters to the MGR system was found to be ineffective, thus creating the need for further research to improve the operational aspects of the MGR system to optimise its capabilities for continuous and industrial-scale operations. The research undertaken in this study, provides information that can be used to classify the dissolved oxygen (DO) transport kinetics into immobilised fixed-films of P. chrysosporium. Operational limitations of the MGR relating to environmental stresses in the bioreactor during operation and to biofilm deterioration, including limitations of DO mass transport, oxidative stress, trace element accumulation and polysaccharide storage in the fungal biomass, were evaluated in single capillary MGR systems (SCMGRs). These conditions were identified as existing in the continuous MGR systems. From DO profiles, the oxygen consumption and flux into the biofilms, including the distribution of DO, was determined to be dependent on the immobilised biofilm’s age. Younger biofilms showed higher DO distribution than older biofilms even when aeration was directed to the extracapillary space (ECS) of the reactor against the biofilm’s surface. An increase in anaerobic zone thickness was observed to be increasing with an increase in biofilm thickness. Although, DO kinetic parameters were comparable with those obtained in submerged mycelia pellets, higher oxygen consumption values were observed in biofilms grown in the SCMGRs. The limitations of MGR were identified as: 1) poor DO distribution in immobilised biofilms because of b-glucan production and storage in the immobilised biomass, resulting in ethanol production; 2) the peroxidation of lipids of the biofilms, which in turn will affect the long-term performance of the biomass caused by oxygenation and 3) trace element ion accumulation enhanced by b-glucan production. Furthermore, trace element ion accumulation was higher in the MGRs than in batch cultures using the same nutrient medium. The development of a perfluorocarbon (PFC) emulsion for the MGRs to counteract these limitations was investigated. The compatibility of the emulsion with oxygen-carrying capacity was shown with an improvement in biomass generation, LiP/MnP production and overall consumption of primary substrates, mainly glucose and ammonium tartrate, in batch cultures. The emulsions investigated were based on the addition of oxygen carriers: Perfluorooctyl bromide (PFOB), Bis-(Perfluorobutyl) ethene (PFBE) and Perfluoropropylamine (PFPA), using Pluronic F 68 (PF 68) as the surfactant. Concentrations of 10 to 30% (w/v) PFC and 8.5% (w/v) PF 68 were tested successfully in batch cultures. The emulsions containing 10% (w/v) PFCs resulted in improved biomass performance as opposed to emulsions with higher PFC oil concentrations. An emulsion containing 10% (w/v) PFOB was used to evaluate its efficacy in the SCMGRs, as the biomass yield and overall enzyme production were superior to PFPA and PFBE-based emulsions with similar oil concentrations. After successfully applying PFOB and PF 68 to the SCMGRs, the following results were obtained: 1) reduced ethanol production; 2) reduced trace element accumulation; 3) lower b-glucan production and 4) improved DO-penetration ratio in immobilised biofilms