title: Modelling water, sediment and nutrient fluxes from a mixed land-use catchment in New Zealand: effects of hydrologic conditions on SWAT model performance

authors: Me, W.

abstract: The Soil Water Assessment Tool (SWAT) was configured for the Puarenga Stream catchment (77 km2), Rotorua, New Zealand. The catchment land use is mostly plantation forest, some of which is spray-irrigated with treated wastewater. A Sequential Uncertainty Fitting (SUFI-2) procedure was used to auto-calibrate unknown parameter values in the SWAT model which was applied to the Puarenga catchment. Discharge, sediment, and nutrient variables were then partitioned into two components (base flow and quick flow) based on hydrograph separation. A manual procedure (one-at a-time sensitivity analysis) was then used to quantify parameter sensitivity for the two hydrologically-separated regimes. Comparison of simulated daily mean discharge, sediment and nutrient concentrations with high-frequency, event-based measurements allowed the error in model predictions to be quantified. This comparison highlighted the potential for model error associated with quick-flow fluxes in flashy lower-order streams to be underestimated compared with low-frequency (e.g. monthly) measurements derived predominantly from base flow measurements. To overcome this problem we advocate the use of high-frequency, event-based monitoring data during calibration and dynamic parameter values with some dependence on discharge regime. This study has important implications for quantifying uncertainty in hydrological models, particularly for studies where model simulations are used to simulate responses of stream discharge and composition to changes in irrigation and land management.

text: Modelling water, sediment and nutrient fluxes from a mixed land-use catchment in New Zealand: effects of hydrologic conditions on SWAT model performance The Soil Water Assessment Tool (SWAT) was configured for the Puarenga Stream catchment (77 km2), Rotorua, New Zealand. The catchment land use is mostly plantation forest, some of which is spray-irrigated with treated wastewater. A Sequential Uncertainty Fitting (SUFI-2) procedure was used to auto-calibrate unknown parameter values in the SWAT model which was applied to the Puarenga catchment. Discharge, sediment, and nutrient variables were then partitioned into two components (base flow and quick flow) based on hydrograph separation. A manual procedure (one-at a-time sensitivity analysis) was then used to quantify parameter sensitivity for the two hydrologically-separated regimes. Comparison of simulated daily mean discharge, sediment and nutrient concentrations with high-frequency, event-based measurements allowed the error in model predictions to be quantified. This comparison highlighted the potential for model error associated with quick-flow fluxes in flashy lower-order streams to be underestimated compared with low-frequency (e.g. monthly) measurements derived predominantly from base flow measurements. To overcome this problem we advocate the use of high-frequency, event-based monitoring data during calibration and dynamic parameter values with some dependence on discharge regime. This study has important implications for quantifying uncertainty in hydrological models, particularly for studies where model simulations are used to simulate responses of stream discharge and composition to changes in irrigation and land management.

year: 2015-04-29

title: Dairy Effluent Steroidal Hormones Characteristics and Treatment by Anaerobic Digestion (Covered Anaerobic Pond) and Biochar

authors: Rachmani, Asaf

subjects: Dairy effluent treatment system

abstract: Endocrine disrupting compounds such as estrogenic steroid hormones (ESHs) are problematic when present in waterways in terms of both the health of the ecosystem and downstream water treatment. Dairy farms are some of the largest contributors to ESHs in the environment. This study focused on a farm located in the Waikato region, New Zealand, which housed 550, primarily grass-fed dairy cows. The farm included a rotary milking shed, feed pad, sump, covered anaerobic pond and storage pond, with effluent and sludge being applied to land. In this study concentrations of the conjugated and unconjugated ESHs, 17α-estradiol (17α-E2), 17β-estradiol (17β-E2) and estrone (E1), in both dissolved and solid phases of dairy shed effluent, and covered anaerobic pond sludge and effluent, were measured from grab samples over a period of nine months. These were used to investigate seasonal variation and performance of the covered anaerobic pond in removing the ESHs and their conversion from one form into another. Previously published methods of ESH analysis were validated and adapted for ESH analysis in dissolved and solid phases, and a new enzymatic method for conjugate ESH analysis was tested and used. In addition, the effect of dosing the effluent with biochar was examined on ESH removal. A covered anaerobic pond model was developed to examine the efficacy of a dairy farm-based covered anaerobic pond treatment system to settle, transform, absorb and remove ESHs. The model was calibrated utilising ESH measurements and used to examine the effect of biochar addition and operational parameters on ESH removal. 

Overall ESH concentrations in the covered anaerobic pond influent, sludge and effluent were 4,171 ng/L, 93,601 ng/L and 4,346 ng/L respectively. ESH concentrations peaked in dairy shed effluent during April and July, which correlated with the late pregnancy and calving periods on the farm. The mean organic carbon normalised adsorption coefficient (Koc) for ESHs in the samples from the pond treatment system ranged between 3.06 mL/g to 3.78 mL/g, comparable with published values in soil and wastewater sludge. Up to 99% of the total mass of ESHs in the sludge and between 70-80 % in influent and effluent were retained in the solids phase. The predominant ESH in the influent samples was 17α-E2 (2,869 ng/L), but E1 predominated in the sludge (85,414 ng/L) and in the effluent (3,140 ng/L). The dissolved and solid phases of dairy shed effluent contained the highest relative proportions of conjugated ESHs with means of 25.1 % and 3.38 % respectively and corresponding mean concentrations of 113 ng/L and 137 ng/L. In contrast, sludge and effluent samples (dissolved and solid phases) from the covered anaerobic pond contained smaller relative proportions of conjugated ESHs, 0.90 % and 1.21 %, and 7.17 % and 0.43 % respectively and corresponding mean concentrations of 6.65 ng/L and 967 ng/L, and 52.5 ng/L and 19.7 ng/L respectively. These results demonstrate the importance of considering the solid fraction within effluent treatment systems when analysing ESHs, otherwise estrogenic load can be greatly underestimated. The conjugated ESHs were present in both the dissolved and solid phases of all samples collected, indicating that conjugated ESHs are persistent and can pass through anaerobic treatment systems contributing to estrogenic load once applied to pasture, and potentially leach into groundwater or migrate to nearby surface waters. Overall anaerobic treatment of dairy waste decreased the contribution of 17α-E2 and 17-E2 while increasing that of E1, however, 17-E2 was the main contributor to total estrogenicity.

The calibration of the model developed provided a good fit with experimental data with an R2 of 0.98-0.99. Addition of biochar into dairy shed effluent and the model covered anaerobic pond system resulted in an 89 % reduction of free ESHs but had a minimal impact on conjugated ESH. Addition of biochar increased the solid phase ESH concentration by 19 % settling out into the sludge and reducing overall estrogenic load in the effluent. Operational factors such as higher influent flow rates and sludge accumulation negatively impacted the covered anaerobic pond ESH removal performance. Sludge accumulation and short-circuiting caused by infrequent removal and shallow depth of the covered anaerobic pond system resulted in mixing of fresh influent with the upper layer of pond sludge, leading to decreased removal efficiency. To enhance the covered anaerobic pond system's performance, increasing the retention time and reducing sludge carry over by increasing pond volume and depth, resulted in ESH removal increasing to 67.9 % (no biochar) and 73.0 % (with biochar), and estrogenicity reduction improving to 70.4 % (no biochar) and 73.5 % (with biochar).

text: Dairy Effluent Steroidal Hormones Characteristics and Treatment by Anaerobic Digestion (Covered Anaerobic Pond) and Biochar Endocrine disrupting compounds such as estrogenic steroid hormones (ESHs) are problematic when present in waterways in terms of both the health of the ecosystem and downstream water treatment. Dairy farms are some of the largest contributors to ESHs in the environment. This study focused on a farm located in the Waikato region, New Zealand, which housed 550, primarily grass-fed dairy cows. The farm included a rotary milking shed, feed pad, sump, covered anaerobic pond and storage pond, with effluent and sludge being applied to land. In this study concentrations of the conjugated and unconjugated ESHs, 17α-estradiol (17α-E2), 17β-estradiol (17β-E2) and estrone (E1), in both dissolved and solid phases of dairy shed effluent, and covered anaerobic pond sludge and effluent, were measured from grab samples over a period of nine months. These were used to investigate seasonal variation and performance of the covered anaerobic pond in removing the ESHs and their conversion from one form into another. Previously published methods of ESH analysis were validated and adapted for ESH analysis in dissolved and solid phases, and a new enzymatic method for conjugate ESH analysis was tested and used. In addition, the effect of dosing the effluent with biochar was examined on ESH removal. A covered anaerobic pond model was developed to examine the efficacy of a dairy farm-based covered anaerobic pond treatment system to settle, transform, absorb and remove ESHs. The model was calibrated utilising ESH measurements and used to examine the effect of biochar addition and operational parameters on ESH removal. 

Overall ESH concentrations in the covered anaerobic pond influent, sludge and effluent were 4,171 ng/L, 93,601 ng/L and 4,346 ng/L respectively. ESH concentrations peaked in dairy shed effluent during April and July, which correlated with the late pregnancy and calving periods on the farm. The mean organic carbon normalised adsorption coefficient (Koc) for ESHs in the samples from the pond treatment system ranged between 3.06 mL/g to 3.78 mL/g, comparable with published values in soil and wastewater sludge. Up to 99% of the total mass of ESHs in the sludge and between 70-80 % in influent and effluent were retained in the solids phase. The predominant ESH in the influent samples was 17α-E2 (2,869 ng/L), but E1 predominated in the sludge (85,414 ng/L) and in the effluent (3,140 ng/L). The dissolved and solid phases of dairy shed effluent contained the highest relative proportions of conjugated ESHs with means of 25.1 % and 3.38 % respectively and corresponding mean concentrations of 113 ng/L and 137 ng/L. In contrast, sludge and effluent samples (dissolved and solid phases) from the covered anaerobic pond contained smaller relative proportions of conjugated ESHs, 0.90 % and 1.21 %, and 7.17 % and 0.43 % respectively and corresponding mean concentrations of 6.65 ng/L and 967 ng/L, and 52.5 ng/L and 19.7 ng/L respectively. These results demonstrate the importance of considering the solid fraction within effluent treatment systems when analysing ESHs, otherwise estrogenic load can be greatly underestimated. The conjugated ESHs were present in both the dissolved and solid phases of all samples collected, indicating that conjugated ESHs are persistent and can pass through anaerobic treatment systems contributing to estrogenic load once applied to pasture, and potentially leach into groundwater or migrate to nearby surface waters. Overall anaerobic treatment of dairy waste decreased the contribution of 17α-E2 and 17-E2 while increasing that of E1, however, 17-E2 was the main contributor to total estrogenicity.

The calibration of the model developed provided a good fit with experimental data with an R2 of 0.98-0.99. Addition of biochar into dairy shed effluent and the model covered anaerobic pond system resulted in an 89 % reduction of free ESHs but had a minimal impact on conjugated ESH. Addition of biochar increased the solid phase ESH concentration by 19 % settling out into the sludge and reducing overall estrogenic load in the effluent. Operational factors such as higher influent flow rates and sludge accumulation negatively impacted the covered anaerobic pond ESH removal performance. Sludge accumulation and short-circuiting caused by infrequent removal and shallow depth of the covered anaerobic pond system resulted in mixing of fresh influent with the upper layer of pond sludge, leading to decreased removal efficiency. To enhance the covered anaerobic pond system's performance, increasing the retention time and reducing sludge carry over by increasing pond volume and depth, resulted in ESH removal increasing to 67.9 % (no biochar) and 73.0 % (with biochar), and estrogenicity reduction improving to 70.4 % (no biochar) and 73.5 % (with biochar).

year: 2024

title: Systemic racism in clinical psychology: Symposia

authors: Wairoa-Harrison, Sophia

subjects: Racial oppression

abstract: This study constitutes a part of the Working to End Racial Oppression (WERO) project on Systemic Racism in Health Education, Training, and Practice. The focus is on the three dimensions of racism in psychology in Aotearoa New Zealand: its costs, systems and the potential responses that exist. Content: To set the scene, the session will begin with a 30-minute presentation that outlines evidence from three WERO studies on different levels of racism affecting indigenous Māori and minoritised groups. First study presents findings from a desktop analysis of papers across university psychology departments. The findings will be compared with previous studies (Levy, 2007; Levy & Waitoki, 2015) to identify the changes in inclusion of Māori and culturally focused paper at different timepoints. The second study involves semi-structured interviews with Māori students enrolled in clinical psychology training programmes (n = 19) to understand the extent of cultural responsiveness, support, disparities, and representation within programmes. The third study draws on preliminary survey findings with directors of training programmes to depict the progress towards including taha Māori and cultural competency in the psychology curriculum since the studies by Abbott and Durie (1987) and Nathan (1999). The rest of the session will be conducted as a wānanga or a forum that includes a panel discussion amongst WERO research team while allowing for a reciprocal exchange of knowledge with the attendees. Opportunities will be provided for attendees to ask questions, provide feedback to the research analyses and findings, and share their experiences of witnessing or encountering racism in psychology. The session will be opened with a karakia (prayer) and attendees to be offered manaakitanga (hospitality) and tikanga (custom) to ensure cultural safety. Goals: In this session, the research team will bring the evidence derived from robust analyses on existence and ramifications of racism in psychology to the fore. These findings will be integrated with the Waitangi Tribunal claim (Levy, 2018) to shed light on the manifestations of racism across systems and agents responsible for the regulation, training and employment of psychologists. Findings will be used to inform ways for all in psychology to embark on Te Tiriti-focused, culturally-competent and equitable approaches in the quest of indigenising the psychology discipline and advancing it to be relevant to the multicultural nature of Aotearoa populations.

text: Systemic racism in clinical psychology: Symposia This study constitutes a part of the Working to End Racial Oppression (WERO) project on Systemic Racism in Health Education, Training, and Practice. The focus is on the three dimensions of racism in psychology in Aotearoa New Zealand: its costs, systems and the potential responses that exist. Content: To set the scene, the session will begin with a 30-minute presentation that outlines evidence from three WERO studies on different levels of racism affecting indigenous Māori and minoritised groups. First study presents findings from a desktop analysis of papers across university psychology departments. The findings will be compared with previous studies (Levy, 2007; Levy & Waitoki, 2015) to identify the changes in inclusion of Māori and culturally focused paper at different timepoints. The second study involves semi-structured interviews with Māori students enrolled in clinical psychology training programmes (n = 19) to understand the extent of cultural responsiveness, support, disparities, and representation within programmes. The third study draws on preliminary survey findings with directors of training programmes to depict the progress towards including taha Māori and cultural competency in the psychology curriculum since the studies by Abbott and Durie (1987) and Nathan (1999). The rest of the session will be conducted as a wānanga or a forum that includes a panel discussion amongst WERO research team while allowing for a reciprocal exchange of knowledge with the attendees. Opportunities will be provided for attendees to ask questions, provide feedback to the research analyses and findings, and share their experiences of witnessing or encountering racism in psychology. The session will be opened with a karakia (prayer) and attendees to be offered manaakitanga (hospitality) and tikanga (custom) to ensure cultural safety. Goals: In this session, the research team will bring the evidence derived from robust analyses on existence and ramifications of racism in psychology to the fore. These findings will be integrated with the Waitangi Tribunal claim (Levy, 2018) to shed light on the manifestations of racism across systems and agents responsible for the regulation, training and employment of psychologists. Findings will be used to inform ways for all in psychology to embark on Te Tiriti-focused, culturally-competent and equitable approaches in the quest of indigenising the psychology discipline and advancing it to be relevant to the multicultural nature of Aotearoa populations.

year: 2023-03-25