Evaluating the performance of horizontal subsurface flow constructed wetlands using natural zeolite (escott)

The objective of the present study was to assess the simultaneous removal of physiochemical parameters in moderate strength wastewater using a lab scale horizontal subsurface flow constructed wetland (HFCW) with natural zeolite as a substrate. In this study, high-density polyethylene tanks (0.36 m²) were planted with phragmites australis and scirpus maritimus and received 0.012 m³/d to 0.08 m³/d of synthetic wastewater corresponding to a HLR of 0.035 to 0.243 m/d and a COD loading rate of 0.0148 kg COD (m².d)^-1 to 0.026 kg COD (m².d)^-1. The HFCW was subjected to three hydraulic retention times (HRT) for 4, 3 and 2 days respectively. Averaged data reported coincided with the plant age (4 to 55 weeks) and covered the entire cold season and early part of the hot season. Based on the 55 weeks of operation, the HFCW unit with zeolite achieved significantly higher removal for COD (85 to 88%), TN (54 to 96%), NH₄-N (50 to 99%) and TSS (91 to 96%) respectively at all HRT. This system was proved to be tolerant to high organic loadings and nutrients, suggesting these substrates as viable options for biological treatment of wastewater.

Consumers' readiness to eat a plant-based diet

Objective: The aim of this study was to examine consumers' readiness to change to a plant-based diet. Design: Mail survey that included questions on readiness to change, eating habits and perceived benefits and barriers to the consumption of a plant-based diet. Setting: Victoria, Australia. Subjects: A total of 415 randomly selected adults. Results: In terms of their readiness to eat a plant-based diet, the majority (58%) of participants were in the precontemplation stage of change, while 14% were in contemplation/preparation, and 28% in action/maintenance. Those in the action/maintenance stage ate more fruit, vegetables, nuts, seeds, whole-meal bread, and cooked cereals than those in earlier stages. There were statistically significant differences in age and vegetarian status between the stages of change, but not for other demographic variables. There were strong differences across the stages of change with regard to perceived benefits and barriers to plant-based diets. For example, those in action/maintenance scored highest for benefit factors associated with well-being, weight, health, convenience and finances, whereas those in the precontemplation stage did not recognise such benefits. Conclusions: These findings can be utilised to help provide appropriate nutrition education and advertising, targeted at specific stages of change. For example, education about how it is possible to obtain iron and protein from a plant-based diet and on the benefits of change, in addition to tips on how to make a gradual, easy transition to a plant-based diet, could help progress precontemplators to later stages.

Public views of the benefits and barriers to the consumption of a plant-based diet

Objective: The aim of this study was to examine consumers' perceived benefits and barriers to the consumption of a plant-based diet. Design: Mail survey that included questions on perceived benefits and barriers to the consumption of a plant-based diet. Setting: Victoria, Australia. Subjects: Four hundred and fifteen randomly selected Victorian adults. Results: The main perceived barrier to adoption of a plant-based diet was a lack of information about plant-based diets (42% agreement). Sex, age and education differences were present in over a quarter of the barrier items. For example, non-university-educated respondents and older people were less willing to change their current eating pattern than were university educated and younger respondents. The main benefits associated with plant-based diets were health benefits, particularly decreased saturated fat intake (79% agreement), increased fibre intake (76%), and disease prevention (70%). Age, sex and education differences with regard to benefits were apparent, although sex differences were more important than age or education differences. Conclusions: The majority of respondents perceived there to be health benefits associated with the consumption of a plant-based diet. Compared with the proportion of respondents who agreed that there were particular benefits of eating a plant-based diet, perceived barriers were relatively low. An understanding of the perceived benefits and barriers of consuming a plant-based diet will help formulate strategies that aim to influence beliefs about plant foods, plant food consumption, and, ultimately, public health.

Effects of long-term fire exclusion and frequent fire on plant community composition: a case study from semi-arid shrublands

Time since last fire and fire frequency are strong determinants of plant community composition in fire-prone landscapes. Our study aimed to establish the influence of time since last fire and fire frequency on plant community composition and diversity of a south-west Australian semi-arid shrubland. We employed a space-for-time approach using four fire age classes: 'young', 8-15years since last fire; 'medium', 16-34; 'old', 35-50; and 'very old', 51-100; and three fire frequency classes: burnt once, twice and three times within the last 50years. Species diversity was compared using one-way ANOVA and species composition using PERMANOVA. Soil and climatic variables were included as covariables to partition underlying environmental drivers. We found that time since last fire influenced species richness, diversity and composition. Specifically, we recorded a late successional transition from woody seeders to long-lived, arid-zone, resprouting shrub species. Fire frequency did not influence species richness and diversity but did influence species composition via a reduction in cover of longer-lived resprouter species - presumably because of a reduced ability to replenish epicormic buds and/or sufficient starch stores. The distinct floristic composition of old and very old habitat, and the vulnerability of these areas to wildfires, indicate that these areas are ecologically important and management should seek to preserve them.