title: Health inequalities and homelessness: Considering material, relational and spatial dimensions

authors: Hodgetts, Darrin

subjects: health

abstract: Homelessness is a pressing health concern involving material hardship, social marginalization and restrained relationships between homeless and housed people. This article links relational aspects of homelessness, and its health consequences, with material and spatial considerations through the use of photo-elicitation interviews with 12 rough sleepers in London. We highlight the relevance of embodied deprivation for a health psychology that is responsive to the ways in which social inequalities can get under the skin of homeless people and manifest as health disparities.

text: Health inequalities and homelessness: Considering material, relational and spatial dimensions Homelessness is a pressing health concern involving material hardship, social marginalization and restrained relationships between homeless and housed people. This article links relational aspects of homelessness, and its health consequences, with material and spatial considerations through the use of photo-elicitation interviews with 12 rough sleepers in London. We highlight the relevance of embodied deprivation for a health psychology that is responsive to the ways in which social inequalities can get under the skin of homeless people and manifest as health disparities.

year: 2007

title: Zooplankton Dynamics in Wastewater Treatment High Rate Algal Ponds and development of effective control methods

authors: Montemezzani, Valerio

subjects: Wastewater treatment High Rate Algal Pond

abstract: High Rate Algal Ponds (HRAPs) are effective and economical open pond to provide near tertiary-level wastewater (WW) treatment, with the nutrients recovered as algal biomass. However, WW treatment performance can be reduced by the establishment of zooplankton grazers which can consume much of the algal biomass within a few days. The high food availability and the near neutral pH in HRAPs offer optimal conditions for the establishment of zooplankton taxa including cladocerans and rotifers. The control of these zooplankton species is essential for the effective operation of HRAPs. This thesis research was aimed at designing cost-effective treatments to control zooplankton population densities applicable to full-scale HRAPs. In this thesis, I: 1) reviewed existing and potential methods for zooplankton control in HRAPs; 2) assessed environmental and biological parameters for two wastewater HRAPs with CO₂ addition using a 14 month large-scale field experiment; 3) assessed chemical CO₂ asphyxiation, biological control of rotifers using competitor species, mechanical disruption of zooplankton using hydrodynamic shear stress, and the mechanical removal of zooplankton using filtration, using controlled laboratory conditions; 4) validated chronic CO₂ asphyxiation of zooplankton, the biocontrol of rotifers using the cladoceran M. tenuicornis and the ostracod H. incongruens, the control of M. tenuicornis using filtration and the hydrodynamic disruption of zooplankton, using outdoor mesocosms with physicochemical and operational conditions similar to those of full scale HRAPs; 5) assessed night time CO₂ asphyxiation to control zooplankton densities in an 8 m³ HRAP over 14 months.
During the 14 months of the field experiment, zooplankton dynamics in paired 8 m³ HRAPs eight species of zooplankton established, with higher water temperatures and longer detention times promoting larger populations. Grazing pressure was associated with changes in the dominance of microalgal species; large and rapid reductions of productivity; reduced nutrient removal; increased colony size, number of cells in colonies and formation of protective spines in microalgae; and higher biomass settleability. Maintaining a dominance of colonial microalgae, operating HRAPs with short retention times, and facilitating competition among zooplankton species showed to potentially reduce grazer populations. Promising options for zooplankton control included physical methods such as filtration, hydrodynamic cavitation, shear, bead mills; chemical methods such as increase of HRAP night-time CO₂ concentration, promotion of the lethal un-ionized ammonia toxicity, use of biocides, and the chitinase inhibitor chitosan; biocontrol using competitor and predatory organisms. In the laboratory tests CO₂ asphyxiation caused acute mortality of all zooplankton species (t<10 min). Increasing the cladoceran Moina tenuicornis to densities >2,500 individuals/L was associated with a decrease in rotifer populations that were ~23% of the population in the control. The ostracod Heterocypris incongruens at densities >1,000 individuals/L were also associated with a decrease in rotifer densities that were ~27% of the population in the control. Hydrodynamic shear stress killed 100% of M. tenuicornis and ~80% of the rotifer Brachionus calyciflorus after a single pass. In outdoor mesocosms a continuous CO₂ concentration of ~100 mg/L maintained low pond water zooplankton densities, while a continuous concentration of ~180 mg/L killed all microcrustaceans and rotifers present. As biocontrol agents, M. tenuicornis at ~2,000 individuals/L reduced average rotifer densities by 90%, and H. incongruens at ~1,000 individuals/L removed all rotifers. Mechanical filtration using 300 µm and 500 µm filters eradicated M. tenuicornis after one and four filtration periods, respectively. Mechanical hydrodynamic stress killed up to 100% of microcrustaceans, and ~50% of larger rotifers. Zooplankton control using night time CO₂ asphyxiation in an 8 m³ HRAP reduced the average population densities of some zooplankton species over the experimental period: M. tenuicornis (41.3%), the copepod Paracyclops fimbriatus (43.9%), the rotifer Filinia longiseta (59.8%), but was associated with higher average population densities of others: H. incongruens (174.4%), the rotifers Asplanchna sieboldi (177.8%), Cephalodella catellina (200.0%), and B. calyciflorus (234.9%). However, the population densities of B. calyciflorus and C. catellina were always reduced after CO₂ treatments with flow rates ≥2 L/min were applied. The cladoceran Daphnia thomsoni and the rotifer Brachionus urceolaris established only in the control HRAP. Zooplankton control by CO₂ asphyxiation improved the overall performance of the treated WW HRAP compared to the control in several ways, including increasing algal biomass (VSS) (150.8%), productivity (151.4%), chlorophyll-a concentration (161.8%), particle size (MCSA) (115.8%), and average settleability efficiency (189.2%). Furthermore, M. tenuicornis was concentrated in the upper 50 mm of a 300 mm deep water column using vertical migration induced by CO₂ concentrations of between 25-180 mg/L in laboratory experiments, and by phototaxis-induced migration in an 8 m³ HRAP. This suggested that mechanical treatments such as filtration and hydrodynamic stress could be performed to the upper layer of the pond water, reducing the amount of water processed and the overall treatment costs. Overall, CO₂ asphyxiation appeared to be the most reliable, versatile, and effective zooplankton control treatment. 
All treatments reduced or eradicated zooplankton populations and promoted higher productivity of microalgae cultures. However, the efficacy of treatments to control diverse zooplankton species differed, and the implementation of any control strategy in a given system requires a preliminary assessment of zooplankton succession to identify the species able to consume the dominant microalgae that could establish in the system. Treatments can be dosed and combined to selectively kill specific zooplankton species. Moreover, zooplankton at controlled densities could potentially be used as a bio tool to improve biomass settleability or to consume unwanted microalgal species.

text: Zooplankton Dynamics in Wastewater Treatment High Rate Algal Ponds and development of effective control methods High Rate Algal Ponds (HRAPs) are effective and economical open pond to provide near tertiary-level wastewater (WW) treatment, with the nutrients recovered as algal biomass. However, WW treatment performance can be reduced by the establishment of zooplankton grazers which can consume much of the algal biomass within a few days. The high food availability and the near neutral pH in HRAPs offer optimal conditions for the establishment of zooplankton taxa including cladocerans and rotifers. The control of these zooplankton species is essential for the effective operation of HRAPs. This thesis research was aimed at designing cost-effective treatments to control zooplankton population densities applicable to full-scale HRAPs. In this thesis, I: 1) reviewed existing and potential methods for zooplankton control in HRAPs; 2) assessed environmental and biological parameters for two wastewater HRAPs with CO₂ addition using a 14 month large-scale field experiment; 3) assessed chemical CO₂ asphyxiation, biological control of rotifers using competitor species, mechanical disruption of zooplankton using hydrodynamic shear stress, and the mechanical removal of zooplankton using filtration, using controlled laboratory conditions; 4) validated chronic CO₂ asphyxiation of zooplankton, the biocontrol of rotifers using the cladoceran M. tenuicornis and the ostracod H. incongruens, the control of M. tenuicornis using filtration and the hydrodynamic disruption of zooplankton, using outdoor mesocosms with physicochemical and operational conditions similar to those of full scale HRAPs; 5) assessed night time CO₂ asphyxiation to control zooplankton densities in an 8 m³ HRAP over 14 months.
During the 14 months of the field experiment, zooplankton dynamics in paired 8 m³ HRAPs eight species of zooplankton established, with higher water temperatures and longer detention times promoting larger populations. Grazing pressure was associated with changes in the dominance of microalgal species; large and rapid reductions of productivity; reduced nutrient removal; increased colony size, number of cells in colonies and formation of protective spines in microalgae; and higher biomass settleability. Maintaining a dominance of colonial microalgae, operating HRAPs with short retention times, and facilitating competition among zooplankton species showed to potentially reduce grazer populations. Promising options for zooplankton control included physical methods such as filtration, hydrodynamic cavitation, shear, bead mills; chemical methods such as increase of HRAP night-time CO₂ concentration, promotion of the lethal un-ionized ammonia toxicity, use of biocides, and the chitinase inhibitor chitosan; biocontrol using competitor and predatory organisms. In the laboratory tests CO₂ asphyxiation caused acute mortality of all zooplankton species (t<10 min). Increasing the cladoceran Moina tenuicornis to densities >2,500 individuals/L was associated with a decrease in rotifer populations that were ~23% of the population in the control. The ostracod Heterocypris incongruens at densities >1,000 individuals/L were also associated with a decrease in rotifer densities that were ~27% of the population in the control. Hydrodynamic shear stress killed 100% of M. tenuicornis and ~80% of the rotifer Brachionus calyciflorus after a single pass. In outdoor mesocosms a continuous CO₂ concentration of ~100 mg/L maintained low pond water zooplankton densities, while a continuous concentration of ~180 mg/L killed all microcrustaceans and rotifers present. As biocontrol agents, M. tenuicornis at ~2,000 individuals/L reduced average rotifer densities by 90%, and H. incongruens at ~1,000 individuals/L removed all rotifers. Mechanical filtration using 300 µm and 500 µm filters eradicated M. tenuicornis after one and four filtration periods, respectively. Mechanical hydrodynamic stress killed up to 100% of microcrustaceans, and ~50% of larger rotifers. Zooplankton control using night time CO₂ asphyxiation in an 8 m³ HRAP reduced the average population densities of some zooplankton species over the experimental period: M. tenuicornis (41.3%), the copepod Paracyclops fimbriatus (43.9%), the rotifer Filinia longiseta (59.8%), but was associated with higher average population densities of others: H. incongruens (174.4%), the rotifers Asplanchna sieboldi (177.8%), Cephalodella catellina (200.0%), and B. calyciflorus (234.9%). However, the population densities of B. calyciflorus and C. catellina were always reduced after CO₂ treatments with flow rates ≥2 L/min were applied. The cladoceran Daphnia thomsoni and the rotifer Brachionus urceolaris established only in the control HRAP. Zooplankton control by CO₂ asphyxiation improved the overall performance of the treated WW HRAP compared to the control in several ways, including increasing algal biomass (VSS) (150.8%), productivity (151.4%), chlorophyll-a concentration (161.8%), particle size (MCSA) (115.8%), and average settleability efficiency (189.2%). Furthermore, M. tenuicornis was concentrated in the upper 50 mm of a 300 mm deep water column using vertical migration induced by CO₂ concentrations of between 25-180 mg/L in laboratory experiments, and by phototaxis-induced migration in an 8 m³ HRAP. This suggested that mechanical treatments such as filtration and hydrodynamic stress could be performed to the upper layer of the pond water, reducing the amount of water processed and the overall treatment costs. Overall, CO₂ asphyxiation appeared to be the most reliable, versatile, and effective zooplankton control treatment. 
All treatments reduced or eradicated zooplankton populations and promoted higher productivity of microalgae cultures. However, the efficacy of treatments to control diverse zooplankton species differed, and the implementation of any control strategy in a given system requires a preliminary assessment of zooplankton succession to identify the species able to consume the dominant microalgae that could establish in the system. Treatments can be dosed and combined to selectively kill specific zooplankton species. Moreover, zooplankton at controlled densities could potentially be used as a bio tool to improve biomass settleability or to consume unwanted microalgal species.

year: 2017

title: A case study of using the He Pikinga Waiora Implementation Framework: Challenges and successes in implementing a twelve-week lifestyle intervention to reduce weight in Māori men at risk of diabetes, cardiovascular disease and obesity

authors: Oetzel, John G.

subjects: Science & Technology

abstract: BACKGROUND: Māori men have stark health inequities around non-communicable diseases. This study describes the case of a partnership attempting to develop and implement a culturally centred intervention through a collaborative partnership to potentially address the inequities. In particular, the partnership followed a participatory, co-design approach using the He Pikinga Waiora (HPW) Implementation Framework; the study presents lessons learnt in addressing health inequities following this framework. METHODS: The partnership involved a university research team and a Māori community health provider. They engaged with other stakeholders and several cohorts of Māori men through a co-design process to adapt a 12-week lifestyle intervention. The co-design process was documented through meeting notes and interviews with partners. Two cohorts participated in separate single group pre-intervention/post-intervention designs with multi-method data collection. Key outcome measures included weight loss, self-reported health, physical activity, and nutrition. Post-intervention data collection included qualitative data. RESULTS: The co-design process resulted in a strong and engaged partnership between the university team and the provider. There were significant challenges in implementing the intervention including having two additional partner organisations dropping out of the partnership just after the initial implementation phase. However, a flexible and adaptable partnership resulted in developing two distinct lifestyle interventions run with 32 Māori men (in two different cohorts of 8 and 24). All but one in the first cohort completed the programme. The first cohort had a modest although statistically insignificant improvement in weight loss (d = 1.04) and body mass index (BMI; d = 1.08). The second cohort had a significant reduction in weight loss (d = 1.16) and BMI (d = 1.15). They also had a significant increase in health-related quality of life (d = 1.7) and self-rated health (d = 2.0). CONCLUSION: The HPW Framework appears to be well suited to advance implementation science for Indigenous communities in general and Māori in particular. The framework has promise as a policy and planning tool to evaluate and design interventions for chronic disease prevention in Indigenous communities. Despite this promise, there are structural challenges in developing and implementing interventions to address health inequities. TRIAL REGISTRATION: Retrospectively registered, Australia New Zealand Clinical Trials Registry, ACTRN12619001783112.

text: A case study of using the He Pikinga Waiora Implementation Framework: Challenges and successes in implementing a twelve-week lifestyle intervention to reduce weight in Māori men at risk of diabetes, cardiovascular disease and obesity BACKGROUND: Māori men have stark health inequities around non-communicable diseases. This study describes the case of a partnership attempting to develop and implement a culturally centred intervention through a collaborative partnership to potentially address the inequities. In particular, the partnership followed a participatory, co-design approach using the He Pikinga Waiora (HPW) Implementation Framework; the study presents lessons learnt in addressing health inequities following this framework. METHODS: The partnership involved a university research team and a Māori community health provider. They engaged with other stakeholders and several cohorts of Māori men through a co-design process to adapt a 12-week lifestyle intervention. The co-design process was documented through meeting notes and interviews with partners. Two cohorts participated in separate single group pre-intervention/post-intervention designs with multi-method data collection. Key outcome measures included weight loss, self-reported health, physical activity, and nutrition. Post-intervention data collection included qualitative data. RESULTS: The co-design process resulted in a strong and engaged partnership between the university team and the provider. There were significant challenges in implementing the intervention including having two additional partner organisations dropping out of the partnership just after the initial implementation phase. However, a flexible and adaptable partnership resulted in developing two distinct lifestyle interventions run with 32 Māori men (in two different cohorts of 8 and 24). All but one in the first cohort completed the programme. The first cohort had a modest although statistically insignificant improvement in weight loss (d = 1.04) and body mass index (BMI; d = 1.08). The second cohort had a significant reduction in weight loss (d = 1.16) and BMI (d = 1.15). They also had a significant increase in health-related quality of life (d = 1.7) and self-rated health (d = 2.0). CONCLUSION: The HPW Framework appears to be well suited to advance implementation science for Indigenous communities in general and Māori in particular. The framework has promise as a policy and planning tool to evaluate and design interventions for chronic disease prevention in Indigenous communities. Despite this promise, there are structural challenges in developing and implementing interventions to address health inequities. TRIAL REGISTRATION: Retrospectively registered, Australia New Zealand Clinical Trials Registry, ACTRN12619001783112.

year: 2020