Assessment of the physicochemical and microbiological qualities of Tyume River in Amathole District in the Eastern Cape Province, South Africa

Sibanda, Timothy https://orcid.org/0000-0002-6864-3796

Title: Assessment of the physicochemical and microbiological qualities of Tyume River in Amathole District in the Eastern Cape Province, South Africa
Creator: Sibanda, Timothy https://orcid.org/0000-0002-6864-3796
Subject: Water -- Purification
Subject: Sewage -- Purification
Date Issued: 2013-05
Date: 2013-05
Type: Doctoral theses
Type: text
Identifier: http://hdl.handle.net/10353/24465
Identifier: vital:62812
Description: The bioflocculant-producing potentials of three marine bacteria isolated from the sediment samples of Algoa Bay in the Eastern Cape Province of South Africa were assessed. Analysis of the partial nucleotide sequence of the 16S rDNA of the bacteria revealed 99 percent, 99 percent, and 98 percent similarity to Cobetia sp. L222, Bacillus sp. A-5A, and Bacillus sp. HXG-C1 respectively and the sequence was deposited in GenBank as Cobetia sp. OAUIFE, Bacillus sp. MAYA and Bacillus sp. Gilbert (accession number JF799092, JF799093, and HQ537128 respectively). Cultivation condition studies for Cobetia sp. OAUIFE revealed that bioflocculant production was optimal with an inoculum size of 2 percent (v/v), initial pH of 6.0, Mn2+ as the metal ion, and glucose as the carbon source. Metal ions, including Na+, K+, Li+, Ca2+and Mg2+ stimulated bioflocculant production resulting in flocculating activity of above 90 percent. This crude bioflocculant is thermally stable, with about 78 percent of its flocculating activity remaining after heating at 100 oC for 25 min. Analysis of the purified bioflocculant revealed it to be an acidic extracellular polysaccharide. FTIR analysis revealed the presence of methoxyl, hydroxyl, and carboxyl - groups in the compound bioflocculant and SEM micrograph of the bioflocculant revealed a crystal-linear structure. On the other hand, bioflocculant production by Bacillus sp. MAYA was optimal when glucose (95.6 percent flocculating activity) and ammonium nitrate (83.3 percent flocculating activity) were used as carbon and nitrogen sources respectively; inoculum size was 2 percent (v/v); initial pH 6; and Ca2+ as coagulant aid. Chemical analysis of the purified bioflocculant shows that it is composed of uronic acid, neutral sugar and protein. FTIR analysis also revealed the presence of methoxyl, hydroxyl, carboxyl and amino- groups in this bioflocculant. The bioflocculant is thermostable with about 65.6 percent residual flocculating activity retained after heating the bioflocculant at 100 oC for 25 min. However bioflocculant production by Bacillus sp. Gilbert was optimal when sodium carbonate (95.2 percent flocculating activity) and potassium nitrate (76.6 percent flocculating activity) were used as carbon and nitrogen sources respectively; inoculum size was 3 percent (v/v); initial pH 9; and Al3+ as cation. The crude bioflocculant retained 44.2 percent residual flocculating activity after heating at 100 oC for 15 min. FTIR analysis reveals the presence of hydroxyl, carboxyl and methylene - groups in the compound bioflocculant. SEM micrograph of the bioflocculant revealed an amorphous compound. The consortia of these bacteria strains also produced bioflocculants with high flocculating activities which were highly efficient in removing turbidity and chemical oxygen demand (COD) from brewery wastewater, diary wastewater and river water. The bioflocculants from the consortia seemed better than traditional flocculants such as alum . The characteristics of the bioflocculant produced by the consortium of Cobetia sp. OAUIFE and Bacillus sp. MAYA showed that this extracellular bioflocculant, composed of 66percent uronic acid and 31percent protein and an optimum flocculation (90 percent) of kaolin suspension, when the dosage concentration was 0.8 mg/ml, under weak alkaline pH of 8, and Ca2+ as a coagulant aid. The bioflocculant is thermally stable, with a high residual flocculating activity of 86.7 percent, 89.3 percent and 87.0 percent after heating at 50 oC, 80 oC and 100 oC for 25 min respectively. The FTIR analysis of the bioflocculant indicated the presence of hydroxyl, amino, carbonyl and carboxyl functional groups. Scanning electron microscopy (SEM) image revealed a crystal-linear spongy-like bioflocculant structure and EDX analysis of the purified bioflocculant showed that the elemental composition in mass proportion of C,N,O,S and P was 6.67:6.23:37.55:0.38:4.42 (percent w/w). However, the characteristics of the bioflocculant produced by the consortium of Cobetia sp OAUIFE and Bacillus sp. Gilbert showed an optimum flocculation (90 percent) of kaolin suspension when the dosage concentration was 0.2 mg/ml, under neutral pH of 7, and Ca2+ as a coagulant aid. The FTIR analysis of the bioflocculant Tyume River water samples were collected monthly, over a 12-month period starting from August 2010 and ending in July 2011, and transported on ice to the Applied and Environmental Microbiology Research Group (AEMREG) Laboratory at the University of Fort Hare, Alice for analyses within 6 h of collection. Electrical conductivity (EC), total dissolved solids (TDS), temperature, pH and dissolved oxygen (DO) of water samples were determined in situ using a multi-parameter ion-specific meter. Concentrations of orthophosphate and total nitrogen (nitrate + nitrite) were determined by standard photometric methods. Total coliforms (TC), faecal coliforms (FC) and enterococci were determined by the membrane filtration method. Viruses in water samples were concentrated using the adsorption-elution method, followed by extraction of viral nucleic acids and purification done using commercially available kits. The concentrations of human enteric viruses in the river-water samples were estimated using quantitative PCR. RNA viruses were quantified in a two-step protocol where RNA was first transcribed into cDNA in a separate reverse-transcription step. Adenovirus species and serotypes were simultaneously detected using serotype-specific multiplex PCR. Norovirus genogroups GI and GII were detected by semi-nested PCR. The risk of infection associated with recreational and domestic use of the water was also estimated. Biochemical oxygen demand (BOD) levels fell within the stipulated BOD guideline of 10 mg/ℓ for surface waters where full contact use is allowed and ≤ 30 mg/ℓ where public access is prohibited, restricted, or infrequent. DO concentrations generally ranged between 7.47 mg/ℓ and 10.42 mg/ℓ, well within the target water quality requirements. The temperature regime ranged between 6°C and 28°C and for most sampling sites, the temperature regimes were within the acceptable limit of no risk (≤ 25°C) for domestic water uses in South Africa. EC ranged between 47 μS/cm and 408 μS/cm well within the South African target water quality EC guideline of 700 μS/cm though it was observed to increase as the river flowed through settlements. The pH in the period beginning September 2010 through to January 2011 was consistently below pH 9, but from February 2011 to June 2011 the pH significantly increased to between pH 10 and pH 11 at most sampling sites. Unpolluted waters normally show a pH of between 6.5 and 8.5. Most of the pH values observed in this study lie between pH 8.5 and pH 10.8 levels which are not far off from the upper level guideline of pH 9.0 for domestic use. Turbidity ranged between 6 NTU and 281 and fell short of the target water quality range (0 NTU to 1 NTU) of no risk for domestic water uses in South Africa. Monthly TDS values and EC values showed direct proportionality. TDS concentrations at all sites fell within the acceptable guideline of 0 mg/ℓ to 450 mg/ℓ of TDS for domestic use. Nutrient profiles were as follows: nitrate (0.18 mg/ℓ to 4.21 mg/ℓ); nitrite (0.02 mg/ℓ to 2.35 mg/ℓ); and orthophosphate (0.06 mg/ℓ to 2.72 mg/ℓ). The bacteriological qualities of the water were poor, exceeding the guideline of 200 CFU/100 mℓ and 33 CFU/100 mℓ for FC and enterococci respectively, for recreational water. FC counts also exceeded the 1 000 CFU/100 mℓ guideline for water used in fresh produce irrigation. Generally, higher counts of TC, FC and enterococci were recorded at the sampling sites located at the lower reaches of the river compared to the upper reaches. Adenovirus was detected in 31percent of the river samples in concentrations ranging between 1.0×100 genome copies/ℓ and 8.49×104 genome copies/ℓ. Serotyping showed the presence of species C adenovirus serotypes 1, 2, 6 and 7, and species F adenovirus serotype 41. The prevalence of norovirus was 4percent while rotavirus was detected in 4percent of river samples in concentrations ranging between 9×100 genome copies/ℓ and 5.64×103 genome copies/ℓ. Hepatitis A virus was detected in 13percent of river samples in concentrations ranging between1.67×103 and 1.64×104 genome copies/ℓ while enteroviruses were not detected. Detection of enteric viruses was inversely correlated to temperature. Risk analysis showed that both hepatitis A virus and adenovirus presented significantly higher risk of infection values compared to rotavirus in the case of ingestion of 10 mℓ or 100 mℓ of water from Tyume River while enteroviruses did not present any significant risk of infection. Tyume River water samples also did not conform to the US Environmental Protection Agency (US EPA) bacterial criteria of 200 CFU/100 mℓ faecal coliforms and 33 CFU/100 mℓ enterococci for bathing waters. Whereas the physicochemical parameters showed that Tyume River water was relatively clean, the bacteriological water quality was poor. Most of the microbiological contamination observed in this study (especially FIBs) can be blamed on inadequate sanitary infrastructure as we observed that open defecation is commonplace in this catchment, which also serves as a conduit for effluent discharges from wastewater-treatment facilities. Enteric viruses were detected along the course of the river in a sporadic pattern, generally not related to natural hydrological cycles and so we conclude that the presence of enteric viruses in the river is suggestive of the dynamics of the same in the host population. Even though the proportion of infective viruses was estimated in this study, fact remains that there is considerable risk of infection posed by the use of raw surface water for either domestic or recreational use. This study further confirmed the lack of correlation between faecal indicator bacteria and enteric virus occurrence in environmental waters, showing that assaying for enteric viruses in environmental waters remains the best method for determining the health risks associated with the use of faecally contaminated water.
Description: Thesis (PhD) -- Faculty of Science and Agriculture, 2013
Format: computer
Format: online resource
Format: application/pdf
Format: 1 online resource (214 leaves)
Format: pdf
Publisher: University of Fort Hare
Publisher: Faculty of Science and Agriculture
Language: English
Rights: University of Fort Hare
Rights: All Rights Reserved
Rights: Open Access

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