Seteno Ntwampe | University of Johannesburg, South Africa (original) (raw)
Papers by Seteno Ntwampe
Physics and Chemistry of the Earth, Parts A/B/C, 2019
Water insecurity is a growing concern globally and the role of groundwater and aquifers in buffer... more Water insecurity is a growing concern globally and the role of groundwater and aquifers in buffering the effects of climate variability and change is increasingly acknowledged due to extended periods of drought in arid regions. Water security can only be fully realised with a more robust understanding of groundwater as a water resource, especially in the O'Kiep area which is in Namaqualand, South Africa. Results of analyses of groundwater samples (n ¼ 8) indicated that pH values met acceptable standards for drinking, while the total dissolved solids (TDS) and electrical conductivity (EC) were however not within the recommended limits. The chemical composition of the groundwater indicated Eh values À 34.1 to À 87.2 mV, indicative of reducing geochemical conditions with the most abundant ions being Cl-, SO 4 2-, NO 3-, F-, Na þ , Ca 2þ , Mg 2þ and K þ. Furthermore, some of the ions were not within the guidelines, i.e. Cl À , SO 4 2þ , Na þ , Ca 2þ and Mg 2þ , but all the potential toxic elements,
Journal of Water Process Engineering
Processes
The treatment of poultry slaughterhouse wastewater (PSW) with an Expanded Granular Sludge-Bed Bio... more The treatment of poultry slaughterhouse wastewater (PSW) with an Expanded Granular Sludge-Bed Bioreactor (EGSB) is hindered by the accumulation and washout of 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 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 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 a...
Food Engineering Reviews, 2019
Food engineering is an important sub-field that requires special attention in the food industry. ... more Food engineering is an important sub-field that requires special attention in the food industry. The application of biochemical process engineering principles in food production often leads to the optimization of certain features of the food production process; similarly, it results in rapid production, improved quality and reduced food losses. Consequently, to address each aspect of food processing including engineering adequately, researchers must have a multidisciplinary approach, using aspects from a number of fields such as microbiology, chemistry, food technology, process engineering and molecular biology. Accordingly, this review focuses on the engineering of various vinegars. Furthermore, cognizance is given to the gaps that need to be addressed in vinegar engineering, particularly to address limitations employed in traditional approaches during vinegar production. Food engineering assessments address numerous functions in integrated systems for which fermentation systems are the primary process. Mathematical models are used to describe the process, simulate future fermentations and describe process performance. Vinegar engineering also includes the use or design of bioreactors intended for improved product yield and rapid production, improved mass or energy transfer efficiencies and the reduction of detrimental hydrodynamics fermentor conditions on the microorganisms used. For vinegar fermentation, bioreactor selection which might include cell immobilization requires that appropriate process control and optimization be conducted using mathematical models, with rates of acetification being influenced by parameters such as the ratio of dissolved oxygen consumption in comparison to acetic acid yield.
Poultry slaughterhouse wastewater contains high concentrations of chemical oxygen demand (COD), t... more Poultry slaughterhouse wastewater contains high concentrations of chemical oxygen demand (COD), total suspended solids (TSSs), fats, oil and grease (FOG), proteins and carbohydrates. It is important that the wastewater is treated to acceptable environmental discharge standards. In this study, the poultry slaughterhouse wastewater (PSW) was treated using two-stage processes consisting of a biological pre-treatment using a biodegrading agent (Eco-flushTM) coupled with a down-flow expanded granular bed reactor (DEGBR). The results showed that the biological pre-treatment was observed to be highly effective for removal of FOG, COD and TSS with a removal efficiency of 80 ± 6.3%, 38 ± 8.4% and 56 ± 7.2%, respectively. The DEGBR showed a stable performance in terms FOG, COD and, TSS removal, with average removal efficiencies of 89 ± 2.8%, 87 ± 9.5%, and 94 ± 3.7%, respectively. The overall removal rate performance of the integrated system of pre-treatment and DEGBR in terms FOG, COD and TS...
Poultry slaughterhouse wastewater contains nutrients that are sufficient for microbial growth; mo... more Poultry slaughterhouse wastewater contains nutrients that are sufficient for microbial growth; moreover, the wastewater has microorganisms which can be harnessed to perform specifi c functions. Additionally, these microorganisms can grow either in planktonic (free floating) mode or sessile (attached) mode. This study focused on the optimisation of bioflocculant production by quantifying flocculation activity, determined using kaolin clay (4 g/L), by isolates prevalent in poultry slaughterhouse wastewater. Subsequent to their identification and characterisation, six bacterial strains were initially isolated from the poultry wastewater. Although all the isolated microorganisms produced bioflocculants under different conditions, i.e. pH and temperature, the strain that produced bioflocculants with a higher flocculation activity was isolate BF-3, a Comamonas sp., achieving a flocculation activity of 93.8% at 32.9 W C and pH 6.5. Fourier transform infrared spectroscopy (FTIR) analysis of the bioflocculant of the isolate, showed the presence of hydroxyl, carboxyl, alkane and amine functional groups, an indication that the bioflocculant was a protein constituent.
Cyanides (CN-) and soluble salts could potentially inhibit biological processes in wastewater tre... more Cyanides (CN-) and soluble salts could potentially inhibit biological processes in wastewater treatment plants (WWTPs), such as nitrification and denitrification. Cyanide in wastewater can alter metabolic functions of microbial populations in WWTPs, thus significantly inhibiting nitrifier and denitrifier metabolic processes, rendering the water treatment processes ineffective. In this study, bacterial isolates that are tolerant to high salinity conditions, which are capable of nitrification and aerobic denitrification under cyanogenic conditions, were isolated from a poultry slaughterhouse effluent. Three of the bacterial isolates were found to be able to oxidise NH4-N in the presence of 65.91 mg/L of free cyanide (CN-) under saline conditions, i.e. 4.5% (w/v) NaCl. The isolates I, H and G, were identified as Enterobacter sp., Yersinia sp. and Serratia sp., respectively. Results showed that 81% (I), 71% (G) and 75% (H) of 400 mg/L NH4-N was biodegraded (nitrification) within 72 h, with the rates of biodegradation being suitably described by first order reactions, with rate constants being: 4.19 h-1 (I), 4.21 h-1 (H) and 3.79 h-1 (G), respectively, with correlation coefficients ranging between 0.82 and 0.89. Chemical oxygen demand (COD) removal rates were 38% (I), 42% (H) and 48% (G), over a period of 168 h with COD reduction being highest at near neutral pH.
Prof SKO Ntwampe, C3 (established researcher) NRF rated (Associate Professor_Chemical Engineering... more Prof SKO Ntwampe, C3 (established researcher) NRF rated (Associate Professor_Chemical Engineering), https://orcid.org/0000-0001-7516-6249, karabosntwampe@gmail.com, University of Johannesburg, South Africa
Biodata summary:
Prof Ntwampe, initially joined the CPUT in 2008 as a full-time lecturer and was promoted to associate professor in 2014, culminating in him being appointed Head of Department of Biotechnology and Consumer Sciences between 2016 and 2018, and thereafter, assuming the role of Head of Department Chemical Engineering in 2019. Between 2005 and 2008, he was a part time lecturer at the CPUT. He was thereafter recruited by the NWU (SA), to join the School of Chemical and Minerals Engineering in 2020, joining the Centre of Excellence for Carbon-Based Fuels, and leading the Water Pollution Monitoring and Remediation Initiatives Research Group in 2021. He is a technical reviewer for some international journals. Previously, he was a DAAD scholar during his doctoral studies, and held several merit scholarships during his postgraduate studies. He received the IWA Biofilms technology paper award in 2018. He established the Bioresource Engineering Research Group (BioERG), which he led until his departure from the CPUT, and in the process receiving numerous awards (Gold, Silver, Bronze) for postgraduate supervision and journal/publications output. At the NWU, he was voted to serve on the Senate and Engineering Faculty Board as a NRF C3 rated researcher and currently co- or supervises Ph.Ds and master’s students at the UJ and also teaches 3rd/4th yr students. He is currently also a certificated copy editor. He holds qualifications, Doctorate in Chemical Engineering (Technical), Higher Diploma in Higher Education and training (Teaching), Certificate: Copy Editing (Continuous professional development), Project management (Continuous professional development). Specialisations are Wastewater treatment, Biochemical (bioprocess) engineering, Bioresource engineering, Green chemistry for nanomaterial synthesis. Yrs of service at HEI’s is 14 yrs (Full time), 3 yrs (Part time). Industrial exp: 1 yr, Somchem/Denel, Leadership experience in HEI’s, 4yrs HoD, 4 yrs HoP, 13 yrs Research Group Leader (PI). Has 189 journals/book chapters/conference proceedings, including supervising masters (MEng, MSc) and (Ph.D, DEng) to completion, some of the postgraduate students trained have won awards such as Research Excellence Award for Next Generation Researchers in SA including inductees to the prestigious SA's Young Academy of Science. Has participated in the following areas: (i) providing leadership and direction in developing a policy framework for a department academic publications programme; (ii) contributing to the formulation of policy, planning and the management of a research group/centres/institutes; (iii) acting as a university management advisor/workshop presenter on matters relating to research funding and promotion of academic staff; (iv) identifying strategies for increased research outputs; (v) provide professional and technical advice in the development of research proposals for staff including their training; (vi) identify training needs and arranging workshops for upgrading of staff positions (ad hominem promotion) and student’s knowledge and skills in research methodology, techniques of data analysis, report writing, research administration, publishing etc.
Invite, 2024
I am pleased to personally inform you that the Special Issue on "Waste Treatment and Sustainable ... more I am pleased to personally inform you that the Special Issue on "Waste Treatment and Sustainable Technologies" is ready, please check it at: https://www.mdpi.com/journal/applsci/special_issues/6K8R7MTXX6.
Best regards
Biochemical Engineering Journal, 2006
Growth kinetics is one of the most important and critical parameters for studying biofilms as the... more Growth kinetics is one of the most important and critical parameters for studying biofilms as they can be used to model mass transfer and biological reactions. Growth parameters of Phanerochaete chrysosporium were quantified based on the utilisation rate of glucose and biofilm generated in single fibre capillary membrane bioreactors (SFCMBR) operated vertically at 37 • C for 264 h. The growth rate constant value of 0.0348 h −1 was used to model the dry biofilm density profile, which was also classified as equivalent to the specific growth rate. The mass of glucose consumed, increased from 0.051 g/day during the lag phase, to 0.145 g/day in the secondary growth phase. An average glucose consumption rate of 94.0 g/m 3 h was determined over the period of 264 h. The average glucose-based growth yield coefficient of approximately 0.202 g biofilm/g glucose was determined. The primary growth phase reached a structural equilibrium (steady state) at an average density of 9.7E05 g/m 3 in the period 168-216 h, with the secondary growth phase occurring after 216 h. The glucose maintenance coefficient value of 0.028 h −1 , was obtained during the biofilm structural equilibrium phase.
The poultry slaughterhouse industry consumes a large volume of potable water for bird processing ... more The poultry slaughterhouse industry consumes a large volume of potable water for bird processing and equipment cleaning, which culminates in the generation of high strength poultry slaughterhouse wastewater (PSW). The wastewater contains high concentrations of organic matter, suspended solids, nitrogen and nutrients. Most poultry slaughterhouses in South Africa (SA) discharge their wastewater into the municipal sewer system after primary treatment. Due to its high strength, PSW does not meet SA's industrial discharge standards. Discharge of untreated PSW to the environment raises environmental health concerns due to pollution of local rivers and fresh water sources, leading to odour generation and the spread of diseases. Thus, the development of a suitable wastewater treatment process for safe PSW discharge to the environment is a necessity. In this study, a biological PSW treatment process using an Expanded Granular Sludge Bed (EGSB) was evaluated. Response surface methodology coupled with central composite design was used to optimize the performance of the EGSB reactor. The dependant variable used for optimization was chemical oxygen demand (COD) removal as a function of two independent variables, hydraulic retention time (HRT) and organic loading rate (OLR). The interactions between HRT, OLR and COD removal were analysed, and a two factorial (2FI) regression was determined as suitable for COD removal modelling. The optimum COD removal of 93% was achieved at an OLR of 2 g-COD/L/d and HRT of 4.8 days. The model correlation coefficient (R 2) of 0.980 indicates that it is a good fit and is suitable for predicting the EGSB's COD removal efficiency.
This study evaluated the performance of a lab-scale poultry slaughterhouse wastewater (PSW) treat... more This study evaluated the performance of a lab-scale poultry slaughterhouse wastewater (PSW) treatment system consisting of a static granular bed reactor (SGBR) coupled with single stage nitrification-denitrification (SND) bioreactor and ultrafiltration membrane module (ufMM) systems. The feasibility of treating PSW to a water quality standard compliant with industrial wastewater discharge standards was investigated. The SGBR was operated at hydraulic retention times (HRTs) ranging from 24 to 96 h and organic loading rates (OLRs) ranging from 0.73 to 12.49 g COD/L.day, for 138 days. The chemical oxygen demand (COD), total suspended solids (TSS), biological oxygen demand (BOD 5) and fats, oils and grease (FOG) removal efficiencies achieved by the SGBR averaged 80%, 95%, 89% and 80%, respectively. The SND bioreactor achieved total nitrogen (TN) removal efficiencies of 33% and 79% for the SGBR effluent, when operated in down-flow mode without aeration and up-flow mode with aeration, respectively. The ufMMs, operated in dead-end filtration mode, were able to further reduce the COD and TSS by an average of 65% and 54%, respectively. The results for the PSW treatment system demonstrated the combined benefits of biological and physical treatment processes, with averaged COD, ortho-phosphate (PO 4 3−-P), TSS and total dissolved solids (TDS) removal efficiencies of 91%, 51%, 97% and 52%, respectively, being achieved over 52 days. The final effluent was deemed suitable for discharge; although, the PO 4 3-and NH 4 +-N requires further monitoring and the PSW treatment system design requires refinement.
The first step towards selecting a suitable treatment option for poultry slaughterhouse wastewate... more The first step towards selecting a suitable treatment option for poultry slaughterhouse wastewater (PSW) treatment is to characterize it. Various parameters such as the pH, tCOD, BOD 5 , TSS, FOG, turbidity, salinity or conductivity were analyzed in this study and provided values significantly higher than discharge limits imposed by various countries. Furthermore, the biodegradability index (BOD 5 /COD) of PSW was determined and averaged a value of 0.61 for the samples collected during normal processing operations in the slaughterhouse and 0.72 for samples collected during the cleaning of equipment after broiler processing operations. This good biodegradabil-ity translated to a good biological decomposition potential, which can be a risk for the environment as a result of untreated effluent, and also highlights the suitability of biological treatment processes for the treatment of such wastewater. Moreover, to reduce the production of chemical waste from the toxic reagents used for some analyses , and to alleviate the cost and the time required for these analyses, linear regressions were used to correlate three water quality parameters (tCOD, BOD 5 , and FOG), interchangeably. These linear regressions provided a good relationship between these parameters, with R 2. 0.9 for the samples collected during normal operation periods; and weaker correlation for the FOG/BOD 5 and FOG/tCOD of samples collected during the cleaning of processing equipment. This was attributed to the high concentration of FOG (5,216 + 2,534) in the samples collected during this period, from the collection of carcass debris and fats left on the equipment during the slaughtering.
This study evaluated the performance of a novel high rate anaerobic bioreactor system for the tre... more This study evaluated the performance of a novel high rate anaerobic bioreactor system for the treatment of poultry slaughterhouse wastewater (PSW). The new system consisted of a granule-based technology operated in a down-flow configuration, with the assistance of medium-sized pumice stones used as packing materials for the retention of the anaerobic granules, to avoid challenges associated with the use of the three-phase separator of up-flow systems and the washout of the anaerobic biomass. Furthermore, a recycling stream was applied to the system to improve the mixing inside the Down-flow Expanded Granular Bed Reactor (DEGBR), i.e. the influent distribution to the granular biomass, and the implementation of intermittent fluidization when required to alleviate the effects of pressure drop in such systems. The DEGBR was operated under mesophilic conditions (30-35°C) and achieved total chemical oxygen demand (tCOD), five-day biological oxygen demand and total suspended solids average removal percentages .95%, and a fats, oils and grease average removal percentage of 93.67% + 4.51, for an organic loading rate varying between 1.1 to 38.9 gCOD/L.day.
This work presents the synthesis of zeolite (Z), magnetic zeolite (MZ) and bio-surfactant-modifie... more This work presents the synthesis of zeolite (Z), magnetic zeolite (MZ) and bio-surfactant-modified magnetic zeolite (BMMZ) by direct fusion of sodium hy-droxide, coal fly ash, and magnetite. The precursors and the synthesised zeo-lites were characterised by scanning electron microscopy (SEM) equipped with an energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer, Emmett and Teller (BET) surface area analyser. The SEM analysis of Z and BMMZ showed the presence of distinct nanocube structures , while the MZ showed aggregated irregular surfaces with crevices at the surface. XRD indicated that the fly ash consists of sillimanite, quartz and mullite, the sodalite in Z, MZ and BMMZ as indicative of NaOH used in the preparation of the zeolites. The EDS analysis based on the Si/Al classification showed that zeolite X was produced. The functional group signified asymmetric and symmetric stretching vibrations of O-H and internal tetra-hedron vibrations of Si-O and Al-O. The modification of the surface of Z with biosurfactant increased the BET surface area by 56.2% in comparison to
Cyanides (CN À) and soluble salts could potentially inhibit biological processes in wastewater tr... more Cyanides (CN À) and soluble salts could potentially inhibit biological processes in wastewater treatment plants (WWTPs), such as nitrification and denitrification. Cyanide in wastewater can alter metabolic functions of microbial populations in WWTPs, thus significantly inhibiting nitrifier and denitrifier metabolic processes, rendering the water treatment processes ineffective. In this study, bacterial isolates that are tolerant to high salinity conditions, which are capable of nitrification and aerobic denitrification under cyanogenic conditions, were isolated from a poultry slaughterhouse effluent. Three of the bacterial isolates were found to be able to oxidise NH 4-N in the presence of 65.91 mg/L of free cyanide (CN À) under saline conditions, i.e. 4.5% (w/v) NaCl. The isolates I, H and G, were identified as Enterobacter sp., Yersinia sp. and Serratia sp., respectively. Results showed that 81% (I), 71% (G) and 75% (H) of 400 mg/L NH 4-N was biodegraded (nitrification) within 72 h, with the rates of biodegradation being suitably described by first order reactions, with rate constants being: 4.19 h À1 (I), 4.21 h À1 (H) and 3.79 h À1 (G), respectively, with correlation coefficients ranging between 0.82 and 0.89. Chemical oxygen demand (COD) removal rates were 38% (I), 42% (H) and 48% (G), over a period of 168 h with COD reduction being highest at near neutral pH.
Biological antimicrobial compounds from yeast can be used to address the critical need for safer ... more Biological antimicrobial compounds from yeast can be used to address the critical need for safer preservatives in food, fruit and beverages. The inhibition of Candida guilliermondii, a common fermented beverage spoilage organism, was achieved using antimicrobial compounds produced by Candida pyralidae KU736785. The antimicrobial production system was modelled and optimised using response surface methodology, with 22.5 C and pH of 5.0 being the optimum conditions. A new concept for quantifying spoilage organism inhibition was developed. The inhibition activity of the antimicrobial compounds was observed to be at a maximum after 17-23 h of fermentation, with C. pyralidae concentration being between 0.40 and 1.25 Â 10 9 CFU ml À1 , while its maximum specific growth rate was 0.31-0.54 h À1 . The maximum inhibitory activity was between 0.19 and 1.08 l contaminated solidified media per millilitre of antimicrobial compound used. Furthermore, the antimicrobial compound formation rate was 0.037-0.086 l VZI ml À1 ACU h À1 , respectively. The response surface methodology analysis showed that the model developed sufficiently described the antimicrobial compound formation rate 1.08 l VZI ml À1 ACU, as 1.17 l VZI ml À1 ACU, predicted under the optimum production conditions.
A microbial consortium which was largely dominated by Thiobacillus sp. and Serratia sp. was evalu... more A microbial consortium which was largely dominated by Thiobacillus sp. and Serratia sp. was evaluated for the biodegradation of thiocyanate (SCN -) and free cyanide (CN -) under neutral to alkaline conditions, in a two-staged stirred tank bioreactor system operated in series. The bioreactors were operated across a range of residence times (7 d to 24 h), SCN -(100-1000 mg SCN -/L) and CN -(200-450 mg CN -/L) concentrations at room temperature (21 -25 °C). The bioreactors were characterised by high SCNdegradation efficiencies (>99.9%) throughout the experimental run except when the microorganisms were temporarily shocked by a pH increase and the introduction of CNwithin the system. Similarly, high CNbiodegradation efficiencies (>99.9%) were observed subsequent to its introduction to the system. Planktonic microbial activity tests by organisms within the bioreactor system revealed high SCNand CNdegradation efficiencies (>80%); a direct indication of high planktonic microbial activity within the bioreactor system. Furthermore, there was an observed total nitrogen removal by the organisms within the system, which demonstrated the nitrification and denitrification capacity of the organisms while the sulphate concentration increased as a result of SCN -biodegradation, over a period of approximately 300 days. This is the first report on the simultaneous biodegradation of high CNand SCNconcentrations, coupled with nitrogen removal under alkaline conditions. The results demonstrated the potential of the process to treat CNand SCNladen wastewaters.
In recent years, developing countries have increased their cassava (Manihot esculenta) production... more In recent years, developing countries have increased their cassava (Manihot esculenta) production for food security. Cassava contains cyanogen glycosides, mainly as linamarin, which through biocatalysis, i.e. enzyme hydrolysis, results in hydrogen cyanide (HCN). HCN is released into the environment through numerous ways with subsequent volatilisation. Thus, the HCN released during the period 2002-2013 was estimated between 0.025 × 10 −3 to 6.71 ppq (African), 0.012 × 10 −3 to 1.01 ppq (Asian) and 0.007 × 10 −3 to 0.920 × 10 −3 ppq (South American). Furthermore, a decade's (2014-2024) projection of HCN volatilisation displays increases of 60.5% (Africa), 57.7% (Asia) and 50.5% (South America) when compared with the current production. Furthermore, gas released during cassava plants' growth, i.e. HCN, NH 3 , and NO 2 , was quantified in healthy plants. Varying concentrations of HCN were released. These further indicated the presence of a pseudohalogenic gas in the environment -a contributor to climate change.
Physics and Chemistry of the Earth, Parts A/B/C, 2019
Water insecurity is a growing concern globally and the role of groundwater and aquifers in buffer... more Water insecurity is a growing concern globally and the role of groundwater and aquifers in buffering the effects of climate variability and change is increasingly acknowledged due to extended periods of drought in arid regions. Water security can only be fully realised with a more robust understanding of groundwater as a water resource, especially in the O'Kiep area which is in Namaqualand, South Africa. Results of analyses of groundwater samples (n ¼ 8) indicated that pH values met acceptable standards for drinking, while the total dissolved solids (TDS) and electrical conductivity (EC) were however not within the recommended limits. The chemical composition of the groundwater indicated Eh values À 34.1 to À 87.2 mV, indicative of reducing geochemical conditions with the most abundant ions being Cl-, SO 4 2-, NO 3-, F-, Na þ , Ca 2þ , Mg 2þ and K þ. Furthermore, some of the ions were not within the guidelines, i.e. Cl À , SO 4 2þ , Na þ , Ca 2þ and Mg 2þ , but all the potential toxic elements,
Journal of Water Process Engineering
Processes
The treatment of poultry slaughterhouse wastewater (PSW) with an Expanded Granular Sludge-Bed Bio... more The treatment of poultry slaughterhouse wastewater (PSW) with an Expanded Granular Sludge-Bed Bioreactor (EGSB) is hindered by the accumulation and washout of 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 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 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 a...
Food Engineering Reviews, 2019
Food engineering is an important sub-field that requires special attention in the food industry. ... more Food engineering is an important sub-field that requires special attention in the food industry. The application of biochemical process engineering principles in food production often leads to the optimization of certain features of the food production process; similarly, it results in rapid production, improved quality and reduced food losses. Consequently, to address each aspect of food processing including engineering adequately, researchers must have a multidisciplinary approach, using aspects from a number of fields such as microbiology, chemistry, food technology, process engineering and molecular biology. Accordingly, this review focuses on the engineering of various vinegars. Furthermore, cognizance is given to the gaps that need to be addressed in vinegar engineering, particularly to address limitations employed in traditional approaches during vinegar production. Food engineering assessments address numerous functions in integrated systems for which fermentation systems are the primary process. Mathematical models are used to describe the process, simulate future fermentations and describe process performance. Vinegar engineering also includes the use or design of bioreactors intended for improved product yield and rapid production, improved mass or energy transfer efficiencies and the reduction of detrimental hydrodynamics fermentor conditions on the microorganisms used. For vinegar fermentation, bioreactor selection which might include cell immobilization requires that appropriate process control and optimization be conducted using mathematical models, with rates of acetification being influenced by parameters such as the ratio of dissolved oxygen consumption in comparison to acetic acid yield.
Poultry slaughterhouse wastewater contains high concentrations of chemical oxygen demand (COD), t... more Poultry slaughterhouse wastewater contains high concentrations of chemical oxygen demand (COD), total suspended solids (TSSs), fats, oil and grease (FOG), proteins and carbohydrates. It is important that the wastewater is treated to acceptable environmental discharge standards. In this study, the poultry slaughterhouse wastewater (PSW) was treated using two-stage processes consisting of a biological pre-treatment using a biodegrading agent (Eco-flushTM) coupled with a down-flow expanded granular bed reactor (DEGBR). The results showed that the biological pre-treatment was observed to be highly effective for removal of FOG, COD and TSS with a removal efficiency of 80 ± 6.3%, 38 ± 8.4% and 56 ± 7.2%, respectively. The DEGBR showed a stable performance in terms FOG, COD and, TSS removal, with average removal efficiencies of 89 ± 2.8%, 87 ± 9.5%, and 94 ± 3.7%, respectively. The overall removal rate performance of the integrated system of pre-treatment and DEGBR in terms FOG, COD and TS...
Poultry slaughterhouse wastewater contains nutrients that are sufficient for microbial growth; mo... more Poultry slaughterhouse wastewater contains nutrients that are sufficient for microbial growth; moreover, the wastewater has microorganisms which can be harnessed to perform specifi c functions. Additionally, these microorganisms can grow either in planktonic (free floating) mode or sessile (attached) mode. This study focused on the optimisation of bioflocculant production by quantifying flocculation activity, determined using kaolin clay (4 g/L), by isolates prevalent in poultry slaughterhouse wastewater. Subsequent to their identification and characterisation, six bacterial strains were initially isolated from the poultry wastewater. Although all the isolated microorganisms produced bioflocculants under different conditions, i.e. pH and temperature, the strain that produced bioflocculants with a higher flocculation activity was isolate BF-3, a Comamonas sp., achieving a flocculation activity of 93.8% at 32.9 W C and pH 6.5. Fourier transform infrared spectroscopy (FTIR) analysis of the bioflocculant of the isolate, showed the presence of hydroxyl, carboxyl, alkane and amine functional groups, an indication that the bioflocculant was a protein constituent.
Cyanides (CN-) and soluble salts could potentially inhibit biological processes in wastewater tre... more Cyanides (CN-) and soluble salts could potentially inhibit biological processes in wastewater treatment plants (WWTPs), such as nitrification and denitrification. Cyanide in wastewater can alter metabolic functions of microbial populations in WWTPs, thus significantly inhibiting nitrifier and denitrifier metabolic processes, rendering the water treatment processes ineffective. In this study, bacterial isolates that are tolerant to high salinity conditions, which are capable of nitrification and aerobic denitrification under cyanogenic conditions, were isolated from a poultry slaughterhouse effluent. Three of the bacterial isolates were found to be able to oxidise NH4-N in the presence of 65.91 mg/L of free cyanide (CN-) under saline conditions, i.e. 4.5% (w/v) NaCl. The isolates I, H and G, were identified as Enterobacter sp., Yersinia sp. and Serratia sp., respectively. Results showed that 81% (I), 71% (G) and 75% (H) of 400 mg/L NH4-N was biodegraded (nitrification) within 72 h, with the rates of biodegradation being suitably described by first order reactions, with rate constants being: 4.19 h-1 (I), 4.21 h-1 (H) and 3.79 h-1 (G), respectively, with correlation coefficients ranging between 0.82 and 0.89. Chemical oxygen demand (COD) removal rates were 38% (I), 42% (H) and 48% (G), over a period of 168 h with COD reduction being highest at near neutral pH.
Prof SKO Ntwampe, C3 (established researcher) NRF rated (Associate Professor_Chemical Engineering... more Prof SKO Ntwampe, C3 (established researcher) NRF rated (Associate Professor_Chemical Engineering), https://orcid.org/0000-0001-7516-6249, karabosntwampe@gmail.com, University of Johannesburg, South Africa
Biodata summary:
Prof Ntwampe, initially joined the CPUT in 2008 as a full-time lecturer and was promoted to associate professor in 2014, culminating in him being appointed Head of Department of Biotechnology and Consumer Sciences between 2016 and 2018, and thereafter, assuming the role of Head of Department Chemical Engineering in 2019. Between 2005 and 2008, he was a part time lecturer at the CPUT. He was thereafter recruited by the NWU (SA), to join the School of Chemical and Minerals Engineering in 2020, joining the Centre of Excellence for Carbon-Based Fuels, and leading the Water Pollution Monitoring and Remediation Initiatives Research Group in 2021. He is a technical reviewer for some international journals. Previously, he was a DAAD scholar during his doctoral studies, and held several merit scholarships during his postgraduate studies. He received the IWA Biofilms technology paper award in 2018. He established the Bioresource Engineering Research Group (BioERG), which he led until his departure from the CPUT, and in the process receiving numerous awards (Gold, Silver, Bronze) for postgraduate supervision and journal/publications output. At the NWU, he was voted to serve on the Senate and Engineering Faculty Board as a NRF C3 rated researcher and currently co- or supervises Ph.Ds and master’s students at the UJ and also teaches 3rd/4th yr students. He is currently also a certificated copy editor. He holds qualifications, Doctorate in Chemical Engineering (Technical), Higher Diploma in Higher Education and training (Teaching), Certificate: Copy Editing (Continuous professional development), Project management (Continuous professional development). Specialisations are Wastewater treatment, Biochemical (bioprocess) engineering, Bioresource engineering, Green chemistry for nanomaterial synthesis. Yrs of service at HEI’s is 14 yrs (Full time), 3 yrs (Part time). Industrial exp: 1 yr, Somchem/Denel, Leadership experience in HEI’s, 4yrs HoD, 4 yrs HoP, 13 yrs Research Group Leader (PI). Has 189 journals/book chapters/conference proceedings, including supervising masters (MEng, MSc) and (Ph.D, DEng) to completion, some of the postgraduate students trained have won awards such as Research Excellence Award for Next Generation Researchers in SA including inductees to the prestigious SA's Young Academy of Science. Has participated in the following areas: (i) providing leadership and direction in developing a policy framework for a department academic publications programme; (ii) contributing to the formulation of policy, planning and the management of a research group/centres/institutes; (iii) acting as a university management advisor/workshop presenter on matters relating to research funding and promotion of academic staff; (iv) identifying strategies for increased research outputs; (v) provide professional and technical advice in the development of research proposals for staff including their training; (vi) identify training needs and arranging workshops for upgrading of staff positions (ad hominem promotion) and student’s knowledge and skills in research methodology, techniques of data analysis, report writing, research administration, publishing etc.
Invite, 2024
I am pleased to personally inform you that the Special Issue on "Waste Treatment and Sustainable ... more I am pleased to personally inform you that the Special Issue on "Waste Treatment and Sustainable Technologies" is ready, please check it at: https://www.mdpi.com/journal/applsci/special_issues/6K8R7MTXX6.
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Biochemical Engineering Journal, 2006
Growth kinetics is one of the most important and critical parameters for studying biofilms as the... more Growth kinetics is one of the most important and critical parameters for studying biofilms as they can be used to model mass transfer and biological reactions. Growth parameters of Phanerochaete chrysosporium were quantified based on the utilisation rate of glucose and biofilm generated in single fibre capillary membrane bioreactors (SFCMBR) operated vertically at 37 • C for 264 h. The growth rate constant value of 0.0348 h −1 was used to model the dry biofilm density profile, which was also classified as equivalent to the specific growth rate. The mass of glucose consumed, increased from 0.051 g/day during the lag phase, to 0.145 g/day in the secondary growth phase. An average glucose consumption rate of 94.0 g/m 3 h was determined over the period of 264 h. The average glucose-based growth yield coefficient of approximately 0.202 g biofilm/g glucose was determined. The primary growth phase reached a structural equilibrium (steady state) at an average density of 9.7E05 g/m 3 in the period 168-216 h, with the secondary growth phase occurring after 216 h. The glucose maintenance coefficient value of 0.028 h −1 , was obtained during the biofilm structural equilibrium phase.
The poultry slaughterhouse industry consumes a large volume of potable water for bird processing ... more The poultry slaughterhouse industry consumes a large volume of potable water for bird processing and equipment cleaning, which culminates in the generation of high strength poultry slaughterhouse wastewater (PSW). The wastewater contains high concentrations of organic matter, suspended solids, nitrogen and nutrients. Most poultry slaughterhouses in South Africa (SA) discharge their wastewater into the municipal sewer system after primary treatment. Due to its high strength, PSW does not meet SA's industrial discharge standards. Discharge of untreated PSW to the environment raises environmental health concerns due to pollution of local rivers and fresh water sources, leading to odour generation and the spread of diseases. Thus, the development of a suitable wastewater treatment process for safe PSW discharge to the environment is a necessity. In this study, a biological PSW treatment process using an Expanded Granular Sludge Bed (EGSB) was evaluated. Response surface methodology coupled with central composite design was used to optimize the performance of the EGSB reactor. The dependant variable used for optimization was chemical oxygen demand (COD) removal as a function of two independent variables, hydraulic retention time (HRT) and organic loading rate (OLR). The interactions between HRT, OLR and COD removal were analysed, and a two factorial (2FI) regression was determined as suitable for COD removal modelling. The optimum COD removal of 93% was achieved at an OLR of 2 g-COD/L/d and HRT of 4.8 days. The model correlation coefficient (R 2) of 0.980 indicates that it is a good fit and is suitable for predicting the EGSB's COD removal efficiency.
This study evaluated the performance of a lab-scale poultry slaughterhouse wastewater (PSW) treat... more This study evaluated the performance of a lab-scale poultry slaughterhouse wastewater (PSW) treatment system consisting of a static granular bed reactor (SGBR) coupled with single stage nitrification-denitrification (SND) bioreactor and ultrafiltration membrane module (ufMM) systems. The feasibility of treating PSW to a water quality standard compliant with industrial wastewater discharge standards was investigated. The SGBR was operated at hydraulic retention times (HRTs) ranging from 24 to 96 h and organic loading rates (OLRs) ranging from 0.73 to 12.49 g COD/L.day, for 138 days. The chemical oxygen demand (COD), total suspended solids (TSS), biological oxygen demand (BOD 5) and fats, oils and grease (FOG) removal efficiencies achieved by the SGBR averaged 80%, 95%, 89% and 80%, respectively. The SND bioreactor achieved total nitrogen (TN) removal efficiencies of 33% and 79% for the SGBR effluent, when operated in down-flow mode without aeration and up-flow mode with aeration, respectively. The ufMMs, operated in dead-end filtration mode, were able to further reduce the COD and TSS by an average of 65% and 54%, respectively. The results for the PSW treatment system demonstrated the combined benefits of biological and physical treatment processes, with averaged COD, ortho-phosphate (PO 4 3−-P), TSS and total dissolved solids (TDS) removal efficiencies of 91%, 51%, 97% and 52%, respectively, being achieved over 52 days. The final effluent was deemed suitable for discharge; although, the PO 4 3-and NH 4 +-N requires further monitoring and the PSW treatment system design requires refinement.
The first step towards selecting a suitable treatment option for poultry slaughterhouse wastewate... more The first step towards selecting a suitable treatment option for poultry slaughterhouse wastewater (PSW) treatment is to characterize it. Various parameters such as the pH, tCOD, BOD 5 , TSS, FOG, turbidity, salinity or conductivity were analyzed in this study and provided values significantly higher than discharge limits imposed by various countries. Furthermore, the biodegradability index (BOD 5 /COD) of PSW was determined and averaged a value of 0.61 for the samples collected during normal processing operations in the slaughterhouse and 0.72 for samples collected during the cleaning of equipment after broiler processing operations. This good biodegradabil-ity translated to a good biological decomposition potential, which can be a risk for the environment as a result of untreated effluent, and also highlights the suitability of biological treatment processes for the treatment of such wastewater. Moreover, to reduce the production of chemical waste from the toxic reagents used for some analyses , and to alleviate the cost and the time required for these analyses, linear regressions were used to correlate three water quality parameters (tCOD, BOD 5 , and FOG), interchangeably. These linear regressions provided a good relationship between these parameters, with R 2. 0.9 for the samples collected during normal operation periods; and weaker correlation for the FOG/BOD 5 and FOG/tCOD of samples collected during the cleaning of processing equipment. This was attributed to the high concentration of FOG (5,216 + 2,534) in the samples collected during this period, from the collection of carcass debris and fats left on the equipment during the slaughtering.
This study evaluated the performance of a novel high rate anaerobic bioreactor system for the tre... more This study evaluated the performance of a novel high rate anaerobic bioreactor system for the treatment of poultry slaughterhouse wastewater (PSW). The new system consisted of a granule-based technology operated in a down-flow configuration, with the assistance of medium-sized pumice stones used as packing materials for the retention of the anaerobic granules, to avoid challenges associated with the use of the three-phase separator of up-flow systems and the washout of the anaerobic biomass. Furthermore, a recycling stream was applied to the system to improve the mixing inside the Down-flow Expanded Granular Bed Reactor (DEGBR), i.e. the influent distribution to the granular biomass, and the implementation of intermittent fluidization when required to alleviate the effects of pressure drop in such systems. The DEGBR was operated under mesophilic conditions (30-35°C) and achieved total chemical oxygen demand (tCOD), five-day biological oxygen demand and total suspended solids average removal percentages .95%, and a fats, oils and grease average removal percentage of 93.67% + 4.51, for an organic loading rate varying between 1.1 to 38.9 gCOD/L.day.
This work presents the synthesis of zeolite (Z), magnetic zeolite (MZ) and bio-surfactant-modifie... more This work presents the synthesis of zeolite (Z), magnetic zeolite (MZ) and bio-surfactant-modified magnetic zeolite (BMMZ) by direct fusion of sodium hy-droxide, coal fly ash, and magnetite. The precursors and the synthesised zeo-lites were characterised by scanning electron microscopy (SEM) equipped with an energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer, Emmett and Teller (BET) surface area analyser. The SEM analysis of Z and BMMZ showed the presence of distinct nanocube structures , while the MZ showed aggregated irregular surfaces with crevices at the surface. XRD indicated that the fly ash consists of sillimanite, quartz and mullite, the sodalite in Z, MZ and BMMZ as indicative of NaOH used in the preparation of the zeolites. The EDS analysis based on the Si/Al classification showed that zeolite X was produced. The functional group signified asymmetric and symmetric stretching vibrations of O-H and internal tetra-hedron vibrations of Si-O and Al-O. The modification of the surface of Z with biosurfactant increased the BET surface area by 56.2% in comparison to
Cyanides (CN À) and soluble salts could potentially inhibit biological processes in wastewater tr... more Cyanides (CN À) and soluble salts could potentially inhibit biological processes in wastewater treatment plants (WWTPs), such as nitrification and denitrification. Cyanide in wastewater can alter metabolic functions of microbial populations in WWTPs, thus significantly inhibiting nitrifier and denitrifier metabolic processes, rendering the water treatment processes ineffective. In this study, bacterial isolates that are tolerant to high salinity conditions, which are capable of nitrification and aerobic denitrification under cyanogenic conditions, were isolated from a poultry slaughterhouse effluent. Three of the bacterial isolates were found to be able to oxidise NH 4-N in the presence of 65.91 mg/L of free cyanide (CN À) under saline conditions, i.e. 4.5% (w/v) NaCl. The isolates I, H and G, were identified as Enterobacter sp., Yersinia sp. and Serratia sp., respectively. Results showed that 81% (I), 71% (G) and 75% (H) of 400 mg/L NH 4-N was biodegraded (nitrification) within 72 h, with the rates of biodegradation being suitably described by first order reactions, with rate constants being: 4.19 h À1 (I), 4.21 h À1 (H) and 3.79 h À1 (G), respectively, with correlation coefficients ranging between 0.82 and 0.89. Chemical oxygen demand (COD) removal rates were 38% (I), 42% (H) and 48% (G), over a period of 168 h with COD reduction being highest at near neutral pH.
Biological antimicrobial compounds from yeast can be used to address the critical need for safer ... more Biological antimicrobial compounds from yeast can be used to address the critical need for safer preservatives in food, fruit and beverages. The inhibition of Candida guilliermondii, a common fermented beverage spoilage organism, was achieved using antimicrobial compounds produced by Candida pyralidae KU736785. The antimicrobial production system was modelled and optimised using response surface methodology, with 22.5 C and pH of 5.0 being the optimum conditions. A new concept for quantifying spoilage organism inhibition was developed. The inhibition activity of the antimicrobial compounds was observed to be at a maximum after 17-23 h of fermentation, with C. pyralidae concentration being between 0.40 and 1.25 Â 10 9 CFU ml À1 , while its maximum specific growth rate was 0.31-0.54 h À1 . The maximum inhibitory activity was between 0.19 and 1.08 l contaminated solidified media per millilitre of antimicrobial compound used. Furthermore, the antimicrobial compound formation rate was 0.037-0.086 l VZI ml À1 ACU h À1 , respectively. The response surface methodology analysis showed that the model developed sufficiently described the antimicrobial compound formation rate 1.08 l VZI ml À1 ACU, as 1.17 l VZI ml À1 ACU, predicted under the optimum production conditions.
A microbial consortium which was largely dominated by Thiobacillus sp. and Serratia sp. was evalu... more A microbial consortium which was largely dominated by Thiobacillus sp. and Serratia sp. was evaluated for the biodegradation of thiocyanate (SCN -) and free cyanide (CN -) under neutral to alkaline conditions, in a two-staged stirred tank bioreactor system operated in series. The bioreactors were operated across a range of residence times (7 d to 24 h), SCN -(100-1000 mg SCN -/L) and CN -(200-450 mg CN -/L) concentrations at room temperature (21 -25 °C). The bioreactors were characterised by high SCNdegradation efficiencies (>99.9%) throughout the experimental run except when the microorganisms were temporarily shocked by a pH increase and the introduction of CNwithin the system. Similarly, high CNbiodegradation efficiencies (>99.9%) were observed subsequent to its introduction to the system. Planktonic microbial activity tests by organisms within the bioreactor system revealed high SCNand CNdegradation efficiencies (>80%); a direct indication of high planktonic microbial activity within the bioreactor system. Furthermore, there was an observed total nitrogen removal by the organisms within the system, which demonstrated the nitrification and denitrification capacity of the organisms while the sulphate concentration increased as a result of SCN -biodegradation, over a period of approximately 300 days. This is the first report on the simultaneous biodegradation of high CNand SCNconcentrations, coupled with nitrogen removal under alkaline conditions. The results demonstrated the potential of the process to treat CNand SCNladen wastewaters.
In recent years, developing countries have increased their cassava (Manihot esculenta) production... more In recent years, developing countries have increased their cassava (Manihot esculenta) production for food security. Cassava contains cyanogen glycosides, mainly as linamarin, which through biocatalysis, i.e. enzyme hydrolysis, results in hydrogen cyanide (HCN). HCN is released into the environment through numerous ways with subsequent volatilisation. Thus, the HCN released during the period 2002-2013 was estimated between 0.025 × 10 −3 to 6.71 ppq (African), 0.012 × 10 −3 to 1.01 ppq (Asian) and 0.007 × 10 −3 to 0.920 × 10 −3 ppq (South American). Furthermore, a decade's (2014-2024) projection of HCN volatilisation displays increases of 60.5% (Africa), 57.7% (Asia) and 50.5% (South America) when compared with the current production. Furthermore, gas released during cassava plants' growth, i.e. HCN, NH 3 , and NO 2 , was quantified in healthy plants. Varying concentrations of HCN were released. These further indicated the presence of a pseudohalogenic gas in the environment -a contributor to climate change.