Phenolic compounds in water and the implications for rapid detection of indicator micro-organisms using ß-D-Galactosidase and ß-D-Glucuronidase
- Authors: Abboo, Sagaran
- Date: 2009
- Subjects: Water -- Purification -- Biological treatment , Pollutants -- Biodegradation , Phenol , Organic water pollutants , Water quality biological assessment , Water -- Pollution
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3978 , http://hdl.handle.net/10962/d1004037 , Water -- Purification -- Biological treatment , Pollutants -- Biodegradation , Phenol , Organic water pollutants , Water quality biological assessment , Water -- Pollution
- Description: Faecal contamination in water is detected using appropriate microbial models such as total coliforms, faecal coliforms and E. coli. Βeta-D-Galactosidase (β-GAL) and Beta-D-glucuronidase (β-GUD) are two marker enzymes that are used to test for the presence of total coliforms and E. coli in water samples, respectively. Various assay methods have been developed using chromogenic and fluorogenic substrates. In this study, the chromogenic substrates chlorophenol red β-D-galactopyranoside (CPRG) for β-GAL and p-nitrophenyl-β-D-galactopyranoside (PNPG) for β-GUD were used. Potential problems associated with this approach include interference from other organisms present in the environment (e.g. plants, algae and other bacteria), as well as the presence of certain chemicals, such as phenolic compounds in water. Phenolic compounds are present in the aquatic environment due to their extensive industrial applications. The USA Enviromental Protection Agency (EPA) lists 11 Priority Pollutant Phenols (PPP) due to their high level of toxicity. This study investigated the interfering effects of the eleven PPP found in water on the enzyme activities of both the β-GAL and β-GUD enzyme assays. The presence of these PPP in the β-GAL and β-GUD enzyme assays showed that over and underestimation of activity may occur due to inhibition or activation of these enzymes. Three types of inhibition to enzyme activities were identified from double reciprocal Lineweaver-Burk plots. The inhibition constants (Ki) were determined for all inhibitory phenolic compounds from appropriate secondary plots. Furthermore, this study presented a validated reverse phase high performance liquid chromatography (RP-HPLC) method, developed for the simultaneous detection, separation and determination of all eleven phenolic compounds found in the environment. This method demonstrated good linearity, reproducibility, accuracy and sensitivity. Environmental water samples were collected from rivers, streams, industrial sites and wastewater treatment plant effluent. These samples were extracted and concentrated using a solid phase extraction (SPE) procedure prior to analysis employing the newly developed HPLC method in this study. Seasonal variations on the presence of the PPP in the environment were observed at certain collection sites. The concentrations found were between 0.033 μg/ml for 2,4-dinitrophenol in a running stream to 0.890 mg/ml for pentachlorophenol from an tannery industrial site. These concentrations of phenolic compounds found in these environments were able to interfere with the β-GAL and β-GUD enzyme assays.
- Full Text:
- Date Issued: 2009
- Authors: Abboo, Sagaran
- Date: 2009
- Subjects: Water -- Purification -- Biological treatment , Pollutants -- Biodegradation , Phenol , Organic water pollutants , Water quality biological assessment , Water -- Pollution
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3978 , http://hdl.handle.net/10962/d1004037 , Water -- Purification -- Biological treatment , Pollutants -- Biodegradation , Phenol , Organic water pollutants , Water quality biological assessment , Water -- Pollution
- Description: Faecal contamination in water is detected using appropriate microbial models such as total coliforms, faecal coliforms and E. coli. Βeta-D-Galactosidase (β-GAL) and Beta-D-glucuronidase (β-GUD) are two marker enzymes that are used to test for the presence of total coliforms and E. coli in water samples, respectively. Various assay methods have been developed using chromogenic and fluorogenic substrates. In this study, the chromogenic substrates chlorophenol red β-D-galactopyranoside (CPRG) for β-GAL and p-nitrophenyl-β-D-galactopyranoside (PNPG) for β-GUD were used. Potential problems associated with this approach include interference from other organisms present in the environment (e.g. plants, algae and other bacteria), as well as the presence of certain chemicals, such as phenolic compounds in water. Phenolic compounds are present in the aquatic environment due to their extensive industrial applications. The USA Enviromental Protection Agency (EPA) lists 11 Priority Pollutant Phenols (PPP) due to their high level of toxicity. This study investigated the interfering effects of the eleven PPP found in water on the enzyme activities of both the β-GAL and β-GUD enzyme assays. The presence of these PPP in the β-GAL and β-GUD enzyme assays showed that over and underestimation of activity may occur due to inhibition or activation of these enzymes. Three types of inhibition to enzyme activities were identified from double reciprocal Lineweaver-Burk plots. The inhibition constants (Ki) were determined for all inhibitory phenolic compounds from appropriate secondary plots. Furthermore, this study presented a validated reverse phase high performance liquid chromatography (RP-HPLC) method, developed for the simultaneous detection, separation and determination of all eleven phenolic compounds found in the environment. This method demonstrated good linearity, reproducibility, accuracy and sensitivity. Environmental water samples were collected from rivers, streams, industrial sites and wastewater treatment plant effluent. These samples were extracted and concentrated using a solid phase extraction (SPE) procedure prior to analysis employing the newly developed HPLC method in this study. Seasonal variations on the presence of the PPP in the environment were observed at certain collection sites. The concentrations found were between 0.033 μg/ml for 2,4-dinitrophenol in a running stream to 0.890 mg/ml for pentachlorophenol from an tannery industrial site. These concentrations of phenolic compounds found in these environments were able to interfere with the β-GAL and β-GUD enzyme assays.
- Full Text:
- Date Issued: 2009
Tertiary treatment in integrated algal ponding systems
- Authors: Wells, Charles Digby
- Date: 2005
- Subjects: Sewage -- Purification -- Anaerobic treatment , Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4068 , http://hdl.handle.net/10962/d1006162 , Sewage -- Purification -- Anaerobic treatment , Water -- Purification -- Biological treatment
- Description: Inadequate sanitation is one of the leading causes of water pollution and consequently illness in many underdeveloped countries, including South Africa and, specifically, the Eastern Cape Province, where cholera has become endemic. As modern wastewater treatment processes are often energy intensive and expensive, they are not suitable for use in these areas. There is thus a need to develop more sustainable wastewater treatment technologies for application in smaller communities. The integrated algal ponding system (IAPS) was identified as a possible solution to this wastewater management problem and was investigated for adaptation to local conditions, at the Rhodes University Environmental Experimental Field Station in Grahamstown, South Africa. The system was monitored over a period of nine years, with various configuration adjustments of the high rate algal pond (HRAP) unit operation investigated. Under standard operating conditions, the system was able to achieve levels of nutrient and organic removal comparable with conventional wastewater treatment works. The mean nitrate level achieved in the effluent was below the 15mg.l-1 South African discharge standard, however, nitrate removal in the IAPS was found to be inconsistent. Although the system was unable to sustain chemical oxygen demand (COD) removal to below the 75mg.l-1 South African discharge standard, a removal rate of 87% was recorded, with the residual COD remaining in the form of algal biomass. Previous studies in the Eastern Cape Province have shown that few small wastewater treatment works produce effluent that meets the microbial count specification. Therefore, in addition to the collation of IAPS data from the entire nine year monitoring period, this study also investigated the use of the HRAP as an independent unit operation for disinfection of effluent from small sewage plants. It was demonstrated that the independent high rate algal pond (IHRAP) as a free standing unit operation could consistently produce water with Escherichia coli counts of 0cfu.100ml-1. The observed effect was related to a number of possible conditions prevailing in the system, including elevated pH, sunlight and dissolved oxygen. It was also found that the IHRAP greatly enhanced the nutrient removal capabilities of the conventional IAPS, making it possible to reliably and consistently maintain phosphate and ammonium levels in the final effluent to below 5mg.l-1 and 2mg.l-1 respectively (South African discharge standards are 10mg.l-1 and 3mg.l-1 in each case). The quality of the final effluent produced by the optimisation of the IAPS would allow it to be used for irrigation, thereby providing an alternative water source in water stressed areas. The system also proved to be exceptionally robust and data collected during periods of intensive and low management regimes were broadly comparable. Results of the 9 year study have demonstrated reliable performance of the IAPS and its use an appropriate, sustainable wastewater treatment option for small communities.
- Full Text:
- Date Issued: 2005
- Authors: Wells, Charles Digby
- Date: 2005
- Subjects: Sewage -- Purification -- Anaerobic treatment , Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4068 , http://hdl.handle.net/10962/d1006162 , Sewage -- Purification -- Anaerobic treatment , Water -- Purification -- Biological treatment
- Description: Inadequate sanitation is one of the leading causes of water pollution and consequently illness in many underdeveloped countries, including South Africa and, specifically, the Eastern Cape Province, where cholera has become endemic. As modern wastewater treatment processes are often energy intensive and expensive, they are not suitable for use in these areas. There is thus a need to develop more sustainable wastewater treatment technologies for application in smaller communities. The integrated algal ponding system (IAPS) was identified as a possible solution to this wastewater management problem and was investigated for adaptation to local conditions, at the Rhodes University Environmental Experimental Field Station in Grahamstown, South Africa. The system was monitored over a period of nine years, with various configuration adjustments of the high rate algal pond (HRAP) unit operation investigated. Under standard operating conditions, the system was able to achieve levels of nutrient and organic removal comparable with conventional wastewater treatment works. The mean nitrate level achieved in the effluent was below the 15mg.l-1 South African discharge standard, however, nitrate removal in the IAPS was found to be inconsistent. Although the system was unable to sustain chemical oxygen demand (COD) removal to below the 75mg.l-1 South African discharge standard, a removal rate of 87% was recorded, with the residual COD remaining in the form of algal biomass. Previous studies in the Eastern Cape Province have shown that few small wastewater treatment works produce effluent that meets the microbial count specification. Therefore, in addition to the collation of IAPS data from the entire nine year monitoring period, this study also investigated the use of the HRAP as an independent unit operation for disinfection of effluent from small sewage plants. It was demonstrated that the independent high rate algal pond (IHRAP) as a free standing unit operation could consistently produce water with Escherichia coli counts of 0cfu.100ml-1. The observed effect was related to a number of possible conditions prevailing in the system, including elevated pH, sunlight and dissolved oxygen. It was also found that the IHRAP greatly enhanced the nutrient removal capabilities of the conventional IAPS, making it possible to reliably and consistently maintain phosphate and ammonium levels in the final effluent to below 5mg.l-1 and 2mg.l-1 respectively (South African discharge standards are 10mg.l-1 and 3mg.l-1 in each case). The quality of the final effluent produced by the optimisation of the IAPS would allow it to be used for irrigation, thereby providing an alternative water source in water stressed areas. The system also proved to be exceptionally robust and data collected during periods of intensive and low management regimes were broadly comparable. Results of the 9 year study have demonstrated reliable performance of the IAPS and its use an appropriate, sustainable wastewater treatment option for small communities.
- Full Text:
- Date Issued: 2005
The molecular microbial ecology of sulfate reduction in the Rhodes BioSURE process
- Authors: Chauke, Chesa Gift
- Date: 2002
- Subjects: Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4082 , http://hdl.handle.net/10962/d1007475 , Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Description: The research reported here investigated the use of a Baffle Reactor in order to study aspects of the biological sulfur cycle, where a floating sulfur biofilm formation occurs and where complex organic compounds provide electron donor sources. The development of a laboratory-scale Baffle Reactor model system satisfied the requirements for sulfate reducing bacterial biomass growth and sulfur biofilm formation. Since relatively little is known about the microbial ecology of floating sulfur biofilm systems, this study was undertaken to describe the sulfate reducing sludge population of the system together with its performance. A combination of culture- and molecular-based techniques were applied in this study in order to investigate the microbial ecology of the sulfate-reducing bacteria component of the system. These techniques enabled the identification and the analysis of the distribution of different sulfate reducing bacterial strains found within the sludge bioreactors. Strains isolated from the sludge were characterised based on culture appearance, gram staining and scanning electron microscopy morphology. Molecular methods based on the PCR-amplified 16S rRNA including denaturing gradient gel electrophoresis were employed in order to characterise sulfate-reducing bacteria within the reactors. Three novel Gram negative sulfate-reducing bacteria strains were isolated from the sludge population. Strains isolated were tentatively named Desulfomonas rhodensis, Desulfomonas makanaiensis, and Clostridium sulforhodensis. Results obtained from the Baffle Reactor showed that three dominant species were isolated from the DNA extracted from the whole bacterial population by peR. Three of these were similar to those mentioned above. The presence of these three novel unidentified species suggest that there are a range of other novel organisms involved in sulfate reduction processes.
- Full Text:
- Date Issued: 2002
- Authors: Chauke, Chesa Gift
- Date: 2002
- Subjects: Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4082 , http://hdl.handle.net/10962/d1007475 , Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
- Description: The research reported here investigated the use of a Baffle Reactor in order to study aspects of the biological sulfur cycle, where a floating sulfur biofilm formation occurs and where complex organic compounds provide electron donor sources. The development of a laboratory-scale Baffle Reactor model system satisfied the requirements for sulfate reducing bacterial biomass growth and sulfur biofilm formation. Since relatively little is known about the microbial ecology of floating sulfur biofilm systems, this study was undertaken to describe the sulfate reducing sludge population of the system together with its performance. A combination of culture- and molecular-based techniques were applied in this study in order to investigate the microbial ecology of the sulfate-reducing bacteria component of the system. These techniques enabled the identification and the analysis of the distribution of different sulfate reducing bacterial strains found within the sludge bioreactors. Strains isolated from the sludge were characterised based on culture appearance, gram staining and scanning electron microscopy morphology. Molecular methods based on the PCR-amplified 16S rRNA including denaturing gradient gel electrophoresis were employed in order to characterise sulfate-reducing bacteria within the reactors. Three novel Gram negative sulfate-reducing bacteria strains were isolated from the sludge population. Strains isolated were tentatively named Desulfomonas rhodensis, Desulfomonas makanaiensis, and Clostridium sulforhodensis. Results obtained from the Baffle Reactor showed that three dominant species were isolated from the DNA extracted from the whole bacterial population by peR. Three of these were similar to those mentioned above. The presence of these three novel unidentified species suggest that there are a range of other novel organisms involved in sulfate reduction processes.
- Full Text:
- Date Issued: 2002
Removal of lead from solution by the non-viable biomass of the water fern Azolla filiculoides
- Authors: Sanyahumbi, Douglas
- Date: 1999
- Subjects: Azolla , Heavy metals -- Absorption and adsorption , Lead , Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3901 , http://hdl.handle.net/10962/d1003960 , Azolla , Heavy metals -- Absorption and adsorption , Lead , Water -- Purification -- Biological treatment
- Description: The removal of lead from aqueous solution and lead-acid battery manufacturing waste-water by the non-viable biomass of the water fern Azolla filiculoides was investigated in both batch and column reactors. The maximum lead uptake by the Azolla biomass at a pH value of approximately 5, was found to be 100 mg lead/g biomass from aqueous solution. Lead removal varied from 30% of the initial lead concentration at pH 1.5 to approximately 95% at pH values of 3.5 and 5.6. Lead removal from aqueous solution decreased to 30% of the initial lead concentration if the lead concentration was initially over 400 mg/l. At initial lead concentrations of less than 400 mg/l, percentage lead removal was found to be over 90% of the initial lead concentration. Lead removal remained at approximately 90% between 10°C and 50°C. Biomass concentration (4-8 mg/l) had little effect on lead removal. The presence of iron (Fe) and lead, copper (Cu) and lead or all three metal ions in solution at varying ratios to each other did not appear to have any significant effect on lead removal. Percentage lead, copper and iron removal from aqueous solution was 80-95, 45-50 and 65-75% respectively for the different multiple-metal solutions studied. No break-through points were observed for lead removal from aqueous solutions in column reactors, with initial lead concentrations of less than 100 mg/l at varying flow rates of 2, 5 and 10 ml/min. This suggested that flow rate, and therefore retention time, had little effect on percentage lead removal from aqueous solution, which was more that 95%, at low initial lead concentrations (less than 100 mg/l). At initial lead concentrations of 200 mg/l or more, an increase in flow rate, which equates to a decrease in column retention time, resulted in break-through points occurring earlier in the column run. Percentage lead removal values, from lead-acid battery efiluent in column systems, of over 95% were achieved. Desorption of approximately 30% and 40% of bound lead was achieved, with 0.5 M HNO₃ in a volume of 50 ml, from two lead-acid battery. Repeated adsorption and desorption of lead by the Azalia biomass over 10 cycles did not result in any decrease in the percentage lead removal from effluent, which strongly suggested that the Azalla biomass could be re-used a number of times without deterioration in its physical integrity, or lead removal capacity. No evidence of deterioration in the Azolla biomass's physical integrity after 10 successive adsorption and desorption procedures was observed using scanning electron microscopy. The Azolla filiculoides biomass was, therefore, found to be able to effectively remove lead from aqueous solution and lead-acid battery effluent repeatedly, with no observed reduction in it's uptake capacity or physical integrity.
- Full Text:
- Date Issued: 1999
- Authors: Sanyahumbi, Douglas
- Date: 1999
- Subjects: Azolla , Heavy metals -- Absorption and adsorption , Lead , Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3901 , http://hdl.handle.net/10962/d1003960 , Azolla , Heavy metals -- Absorption and adsorption , Lead , Water -- Purification -- Biological treatment
- Description: The removal of lead from aqueous solution and lead-acid battery manufacturing waste-water by the non-viable biomass of the water fern Azolla filiculoides was investigated in both batch and column reactors. The maximum lead uptake by the Azolla biomass at a pH value of approximately 5, was found to be 100 mg lead/g biomass from aqueous solution. Lead removal varied from 30% of the initial lead concentration at pH 1.5 to approximately 95% at pH values of 3.5 and 5.6. Lead removal from aqueous solution decreased to 30% of the initial lead concentration if the lead concentration was initially over 400 mg/l. At initial lead concentrations of less than 400 mg/l, percentage lead removal was found to be over 90% of the initial lead concentration. Lead removal remained at approximately 90% between 10°C and 50°C. Biomass concentration (4-8 mg/l) had little effect on lead removal. The presence of iron (Fe) and lead, copper (Cu) and lead or all three metal ions in solution at varying ratios to each other did not appear to have any significant effect on lead removal. Percentage lead, copper and iron removal from aqueous solution was 80-95, 45-50 and 65-75% respectively for the different multiple-metal solutions studied. No break-through points were observed for lead removal from aqueous solutions in column reactors, with initial lead concentrations of less than 100 mg/l at varying flow rates of 2, 5 and 10 ml/min. This suggested that flow rate, and therefore retention time, had little effect on percentage lead removal from aqueous solution, which was more that 95%, at low initial lead concentrations (less than 100 mg/l). At initial lead concentrations of 200 mg/l or more, an increase in flow rate, which equates to a decrease in column retention time, resulted in break-through points occurring earlier in the column run. Percentage lead removal values, from lead-acid battery efiluent in column systems, of over 95% were achieved. Desorption of approximately 30% and 40% of bound lead was achieved, with 0.5 M HNO₃ in a volume of 50 ml, from two lead-acid battery. Repeated adsorption and desorption of lead by the Azalia biomass over 10 cycles did not result in any decrease in the percentage lead removal from effluent, which strongly suggested that the Azalla biomass could be re-used a number of times without deterioration in its physical integrity, or lead removal capacity. No evidence of deterioration in the Azolla biomass's physical integrity after 10 successive adsorption and desorption procedures was observed using scanning electron microscopy. The Azolla filiculoides biomass was, therefore, found to be able to effectively remove lead from aqueous solution and lead-acid battery effluent repeatedly, with no observed reduction in it's uptake capacity or physical integrity.
- Full Text:
- Date Issued: 1999
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