title: Effect of activated carbon, oxidation and UV treatment on 2-methylisoborneol and geosmin removal from treated water

authors: Yan, Junfeng

subjects: activated carbon

abstract: Geosmin and 2-methylisoborneol (MIB) are two contributors to taste and odour in water, and originate from cyanobacteria and other microorganisms in surface water.  This thesis examined the use of activated carbon, hydrogen peroxide and UV treatment on removal of these two compounds from water.

Geosmin and MIB were analysed using headspace solid phase micro-extraction (SPME) and gas chromatography coupled with mass spectrometry and flame ionization detection.  Method development examined the effect of salt addition, sample heating time, and extraction time on GC peak area.  Salt addition gave up to 40% lower GC peak areas for MIB and geosmin compared to samples without salt, while increasing sample heating time and extraction time increased GC peak area, increasing the lower detection limits.  Two minutes extraction time gave peak areas 75% of that for 10 minutes extraction time.  Both GC-MS and GC-FID were reliable methods for analysis with standard deviations being less than 5% of the average peak area obtained from the GC.

Activated carbon was effective at removing geosmin and MIB, with 500 mg GAC per L removing 90% of the geosmin and MIB.  Geosmin absorption showed a type II isotherm suggesting monolayer followed by multilayer absorption, while MIB absorption was almost linear.  Langmuir-Freundlich and Freundlich isotherms fitted the MIB data well but not as well for geosmin.  Oxidative treatment using H2O2 removed 84 % of geosmin and 49 % of MIB.  UV degradation of geosmin and MIB using the Steriflo system removed up to 31 % of MIB and 76 % of geosmin after 4 hours.  After 18 hours, geosmin had 84 % removal while MIB was only 66 %.  Addition of H2O2 increased removal for MIB and geosmin up to 89 and 90 % respectively after 18 hours.  Experimental results were simulated using a model that accounted for UV and hydrogen peroxide degradation, using one set of parameters over a range of conditions for each of MIB and geosmin.

text: Effect of activated carbon, oxidation and UV treatment on 2-methylisoborneol and geosmin removal from treated water Geosmin and 2-methylisoborneol (MIB) are two contributors to taste and odour in water, and originate from cyanobacteria and other microorganisms in surface water.  This thesis examined the use of activated carbon, hydrogen peroxide and UV treatment on removal of these two compounds from water.

Geosmin and MIB were analysed using headspace solid phase micro-extraction (SPME) and gas chromatography coupled with mass spectrometry and flame ionization detection.  Method development examined the effect of salt addition, sample heating time, and extraction time on GC peak area.  Salt addition gave up to 40% lower GC peak areas for MIB and geosmin compared to samples without salt, while increasing sample heating time and extraction time increased GC peak area, increasing the lower detection limits.  Two minutes extraction time gave peak areas 75% of that for 10 minutes extraction time.  Both GC-MS and GC-FID were reliable methods for analysis with standard deviations being less than 5% of the average peak area obtained from the GC.

Activated carbon was effective at removing geosmin and MIB, with 500 mg GAC per L removing 90% of the geosmin and MIB.  Geosmin absorption showed a type II isotherm suggesting monolayer followed by multilayer absorption, while MIB absorption was almost linear.  Langmuir-Freundlich and Freundlich isotherms fitted the MIB data well but not as well for geosmin.  Oxidative treatment using H2O2 removed 84 % of geosmin and 49 % of MIB.  UV degradation of geosmin and MIB using the Steriflo system removed up to 31 % of MIB and 76 % of geosmin after 4 hours.  After 18 hours, geosmin had 84 % removal while MIB was only 66 %.  Addition of H2O2 increased removal for MIB and geosmin up to 89 and 90 % respectively after 18 hours.  Experimental results were simulated using a model that accounted for UV and hydrogen peroxide degradation, using one set of parameters over a range of conditions for each of MIB and geosmin.

year: 2016

title: Fononga 'A Fakahalafononga: Tongan Students' Journey to Academic Achievement in New Zealand Tertiary Education

authors: Kalavite, Telesia

subjects: Tongan Education in New Zealand

abstract: There is a national concern in New Zealand about the low academic achievement of Pasifika students, including the Tongans as one of the specific groups. The literature shows that the problems associated with the academic achievement of Pasifika students derive from the cultural differences between Pasifika and the dominant Pālangi culture. Since Tonga has a unique culture that is not the same as any other cultural group in the Pacific, this research set out to explore specific Tongan socio-cultural aspects that impact on Tongan students’ academic achievement in New Zealand tertiary education. Culturally specific aspects that impact on Tongan students’ academic achievement could better inform those who are concerned with the education of Tongans in New Zealand. The purpose of the research is to explore possibilities for enhancing the academic achievement of Tongan students that could bridge the disparity between Pasifika and Pālangi academic achievement. This research used a Tongan, Pasifika, qualitative, phenomenological, ethnographical, methodological framework to explore the views of twenty five Tongan-born participants in New Zealand on the perceived socio-cultural aspects that impact on their academic achievement. It provided opportunities for the participants to reflect on their experiences as university and polytechnic students, as staff and educators, and as parents. Sociocultural, postmodernism, and the Tongan tā-vā, (time-space) theory of reality were used to interpret the Tongan students’ inter-cultural learning experiences at two levels of reality; the students’ realities, and the global realities. The students’ realities include their individual attitudes and choices based on their cultural worldviews that impact on their academic achievement. The global realities include the trends of postmodernism, biculturalism, multiculturalism, globalisation and change which are beyond the students’ control. The key findings of this research were that Tongan students perceived they were academically successful when all parties involved had a deep and mutual understanding of, respect for, and practice in, both Tongan and New Zealand social and academic cultures. In particular, the Tongan students and their Tongan supporters need a deep and mutual understanding of, respect for, and practice in, their own Tongan as well as New Zealand social and academic relationships. New Zealanders who are involved with Tongan students’ education need a deep and mutual understanding of, respect for, and practice in, Tongan social and academic relationships. Furthermore, flexibility within the two cultural relationships in terms of tā (time) and vā (space) should be considered by all parties to release social tensions and consequently enhance academic achievement. This two way process allows Tongan students to move fluidly within the two cultures, especially if they understand how tā (time) and vā (space) are manifested in relationships within their learning environments. This research is highly relevant for anyone concerned with Tongan students’ academic achievement in New Zealand tertiary education; from the top level policy makers in the government to the Tongan students at the grassroots level.

text: Fononga 'A Fakahalafononga: Tongan Students' Journey to Academic Achievement in New Zealand Tertiary Education There is a national concern in New Zealand about the low academic achievement of Pasifika students, including the Tongans as one of the specific groups. The literature shows that the problems associated with the academic achievement of Pasifika students derive from the cultural differences between Pasifika and the dominant Pālangi culture. Since Tonga has a unique culture that is not the same as any other cultural group in the Pacific, this research set out to explore specific Tongan socio-cultural aspects that impact on Tongan students’ academic achievement in New Zealand tertiary education. Culturally specific aspects that impact on Tongan students’ academic achievement could better inform those who are concerned with the education of Tongans in New Zealand. The purpose of the research is to explore possibilities for enhancing the academic achievement of Tongan students that could bridge the disparity between Pasifika and Pālangi academic achievement. This research used a Tongan, Pasifika, qualitative, phenomenological, ethnographical, methodological framework to explore the views of twenty five Tongan-born participants in New Zealand on the perceived socio-cultural aspects that impact on their academic achievement. It provided opportunities for the participants to reflect on their experiences as university and polytechnic students, as staff and educators, and as parents. Sociocultural, postmodernism, and the Tongan tā-vā, (time-space) theory of reality were used to interpret the Tongan students’ inter-cultural learning experiences at two levels of reality; the students’ realities, and the global realities. The students’ realities include their individual attitudes and choices based on their cultural worldviews that impact on their academic achievement. The global realities include the trends of postmodernism, biculturalism, multiculturalism, globalisation and change which are beyond the students’ control. The key findings of this research were that Tongan students perceived they were academically successful when all parties involved had a deep and mutual understanding of, respect for, and practice in, both Tongan and New Zealand social and academic cultures. In particular, the Tongan students and their Tongan supporters need a deep and mutual understanding of, respect for, and practice in, their own Tongan as well as New Zealand social and academic relationships. New Zealanders who are involved with Tongan students’ education need a deep and mutual understanding of, respect for, and practice in, Tongan social and academic relationships. Furthermore, flexibility within the two cultural relationships in terms of tā (time) and vā (space) should be considered by all parties to release social tensions and consequently enhance academic achievement. This two way process allows Tongan students to move fluidly within the two cultures, especially if they understand how tā (time) and vā (space) are manifested in relationships within their learning environments. This research is highly relevant for anyone concerned with Tongan students’ academic achievement in New Zealand tertiary education; from the top level policy makers in the government to the Tongan students at the grassroots level.

year: 2010

title: Māori academic success: Why the deficit perspectives?

authors: Aporosa, S. 'Apo'

subjects: Māori

abstract: Academics have long discussed the power of communication to both motivate and discourage. Concerning education, Paulo Freire (1997) had explained the dialogical learning process and the empowerment that comes from the inclusion of student knowledge. Alternatively, Carlson & Dimitriadis (2003) describe disempowerment and underachievement among Afro-American students resulting from societal expectations that they will fail. In a recent education environment scan focused on the Waikato-Tainui rohe, 28 kaupapa Māori education providers were identified as sites of high educational success, with one described as “outshining private schools and bucking national trends” (Carson, 2013). This aside, perceptions of generalized educational failure among Māori are commonplace in Aotearoa New Zealand. These impressions are fed by the media, the Ministry of Education (MOE) and in some cases, academic publications. This paper discusses the power of deficit models and counter-narratives to academic underachievement. This will be juxtaposed with commentary on why some students and their education providers within the Waikato-Tainui rohe appear to be unaffected by these counter- narratives and deficit theorizing.

text: Māori academic success: Why the deficit perspectives? Academics have long discussed the power of communication to both motivate and discourage. Concerning education, Paulo Freire (1997) had explained the dialogical learning process and the empowerment that comes from the inclusion of student knowledge. Alternatively, Carlson & Dimitriadis (2003) describe disempowerment and underachievement among Afro-American students resulting from societal expectations that they will fail. In a recent education environment scan focused on the Waikato-Tainui rohe, 28 kaupapa Māori education providers were identified as sites of high educational success, with one described as “outshining private schools and bucking national trends” (Carson, 2013). This aside, perceptions of generalized educational failure among Māori are commonplace in Aotearoa New Zealand. These impressions are fed by the media, the Ministry of Education (MOE) and in some cases, academic publications. This paper discusses the power of deficit models and counter-narratives to academic underachievement. This will be juxtaposed with commentary on why some students and their education providers within the Waikato-Tainui rohe appear to be unaffected by these counter- narratives and deficit theorizing.

year: 2016