Effect of organic carbon enrichment on the treatment efficiency of primary settled wastewater by Chlorella vulgaris

This work evaluated the performance of a microalgae treatment process for settled municipal wastewater in a laboratory setting under static culturing conditions, as an alternative to traditional, energy intensive secondary and tertiary wastewater treatment systems. Primary tank settled wastewater (PSW) was first enriched with small quantities of glucose (< 300 mg L− 1) as an organic carbon source to facilitate the bioremediation by the mixotrophic microalga Chlorella vulgaris. Characterisation of the wastewater revealed significant reductions in NH3-N (from 28.9 to 0.1 mg L− 1) and PO4-P, (from 3.2 to 0.1 mg L− 1) in just 2 days. Additionally, the exogenous glucose appeared completely removed from the wastewater after the first day. These achieved levels of treatment in respect of both the NH3-N and PO4-P were much higher than those recorded without C. vulgaris treatment with or without glucose enrichment. This would mean that the microalgae were chiefly responsible for removing the inorganic nitrogen and phosphorus, while the naturally occurring heterotrophic organisms had consumed the carbonaceous matter. The reliability of this process was evaluated across a further three independent batches of PSW with varying compositions of these inorganics and chemical oxygen demand using alternative organic (glycerol) and inorganic (CO2) carbon sources. The efficiency of the microalgae treatment process at reducing NH3-N and PO4-P was consistent in PSW enriched with organic carbon, resulting in > 90% reduction of the inorganic compounds in each batch. The results demonstrate that microalgal culturing processes to treat PSW in bioreactors without aeration are a key area to develop as an alternative biological treatment option

Age-related macular degeneration patients' awareness of nutritional factors

Age-related macular degeneration (AMD) is the leading cause of visual impairment in older adults in the United Kingdom. This study sought to characterise AMD patients who seek the services of the Macular Society, and determine the level and source of their dietary knowledge. A questionnaire was designed, validated, and administered to 158 participants. The questions covered demographic data and knowledge of nutrition and supplementation. The mean age of participants was 79 years; 61% of them were female, and 27% were registered visually impaired. Only 55% of the participants thought diet was important for eye health, 63% felt that they had not received enough information about AMD. The participants reported that their information mainly came from non-professional support groups. Most participants identified healthy food, but could not say why, and were not able to identify carotenoid rich foods. The results of the study will inform design of education and dissemination methods regarding dietary information

Evaluation of a clinical decision making aid for nutrition advice in age-related macular degeneration

Age-related macular disease (AMD) is a multifactorial degenerative condition affecting the central area of the retina. Patients with AMD report that eye care practitioners are not giving consistent advice regarding nutrition and reported confusion as to what advice, if any, to follow. The aim of this study was to design and conduct a preliminary evaluation of a flowchart to support eye care practitioners in providing accurate, evidence-based nutritional advice to their patients. A flowchart was designed to take practitioners through a decision-making process that would determine whether a patient matched the Age-Related Eye Disease Study (AREDS) 2 eligibility criteria for supplementation. The flowchart was evaluated using a qualified and student optometrist cohort, with both cohorts completing confidence scales and students completing clinical scenarios. Qualified participants showed a significant increase in confidence scores from the initial survey (M = 69.7%, standard deviation [SD] = 16.2%) to the second survey after use of the flowchart for 2 weeks (M = 82.1%, SD = 11.6%; t(45) = 7.33, p < .001; rs = .61, p < .001). The student participants also increased confidence scored after receiving the flowchart (M of first survey = 41.7, SD = 14.6; M of second survey = 69.1, SD = 1.7; t(25) = 7.92, d = .81, p < .001) and increased the number of correct answers on five clinical scenarios. Overall, the flowchart has proved to be useful in boosting the self-efficacy of both qualified practitioners and student practitioners, as well as improving clinical decisions made by student practitioners

Broadening Exposure to Socio-Political Opinions via a Pushy Smart Home Device

Motivated by the effects of the filter bubble and echo chamber phenomena on social media, we developed a smart home device, Spkr, that unpredictably “pushes” socio-political discussion topics into the home. The device utilised trending Twitter discussions, categorised by their socio-political alignment, to present people with a purposefully assorted range of viewpoints. We deployed Spkr in 10 homes for 28 days with a diverse range of participants and interviewed them about their experiences. Our results show that Spkr presents a novel means of combating selective exposure to socio-political issues, providing participants with identifiably diverse viewpoints. Moreover, Spkr acted as a conversational prompt for discussion within the home, initiating collective processes and engaging those who would not often be involved in political discussions. We demonstrate how smart home assistants can be used as a catalyst for provocation by altering and pluralising political discussions within households

Contaminant issues in production and application of biochar

For widespread use of biochar in agriculture and horticulture, it must be ensured that application will neither adversely affect soil and plants, nor exceed legislated contaminant concentrations. The most relevant groups of contaminants in biochar are potentially toxic elements (PTEs), polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOC). In this thesis, the concentrations of these groups of contaminants were analysed in 90 different biochars produced by slow pyrolysis. Subsequently, the concentrations were compared to legislation/guideline threshold values and linked to production conditions. The risk these contaminants pose to plant growth was also assessed, to give recommendations on production of safe biochar. PTEs can neither be formed nor destroyed, which means their presence in biochar is predominantly determined by feedstock type. However, significant levels of Cr, Fe and Ni were introduced into biochar from the furnace steel, whilst PTEs with low boiling points, such as As, Cd and Zn, partially evaporated during pyrolysis. PTEs were not responsible for phytotoxic effects observed for PTE-rich biochars despite biochar’s exceedance of available and total PTE threshold values for soil and soil amendments. Although initial tests were promising, the risk that PTE-rich biochars as amendment for soil and growing media pose, needs further investigation. The PAH concentration in biochar was markedly reduced by increasing carrier gas flow rate, and the type of feedstock also influenced the PAH content. However, there was no clear dependence of pyrolysis temperature on PAH concentrations, which was attributed to PAHs being increasingly formed and evaporated at higher pyrolysis temperatures. Ultimately, condensation of pyrolysis vapours and deposition on biochar was identified as the main risk for biochar contamination with PAHs, as this resulted in elevated concentrations of high-risk, higher molecular weight PAHs. Weaknesses in the pyrolysis unit design, such as cold zones, resulted in elevated concentrations of VOCs, as well as PAHs, in biochar. Comparing concentrations and phytotoxic potential of both compound groups, it was concluded that observed toxic effects were much more likely caused by VOCs in biochars containing both contaminants. Overall, formation of VOCs and PAHs cannot be prevented, but their presence in biochar resulting from retention and deposition can be minimised

Tendering design when price and quality is uncertain

Purpose: The purpose of this paper is to analyze how local and central authorities choose between lowest price and more complex scoring rules when they design supplier-selection mechanisms for public procurements. Five hypotheses are tested: a high level of cost uncertainty and highly non-verifiable quality makes the use of the lowest-price supplier-selection method less likely. Organizational habits and transaction-cost considerations influence the choice of mechanism. Strong quality concerns make complex rules more likely. Design/methodology/approach: The analysis departures from normative theory (rational choice) and is based on the regression analysis and survey data comprising a gross sample of 40 contracting authorities and detailed information about 651 procurements. Findings: More complex scoring rules are used more often when the authority is uncertain about costs and about delivered quality. Authority effects are also found to directly and indirectly influence the choice of supplier-selection method, suggesting that tendering design is partly driven by local habits and institutional inertia. Practical implications: The authors argue that, from a normative point of view, lowest price is an adequate method when the degree of uncertainty is low, for example, because the procured products are standardized and since quality can be verified. When there is significant cost uncertainty, it is better to use the so-called economically most advantageous tender (EMAT) method. (Preferably this should be done by assigning monetary values to different quality levels.) If there is significant uncertainty concerning delivered quality, the contracting authority should retain a degree of discretion, so as to be able to reward good-quality performance in observable but non-verifiable quality dimensions; options to extend the contract and subjective assessments of quality are two possibilities. The main findings are that EMAT and more complex scoring rules are used more often when the contracting authorities report that they experience substantial uncertainty concerning delivered quality and actual costs and that these factors tend to decrease the weight given to price, in line with the predictions. However, the authors also find that this result is mainly driven by variations between authorities, rather than by between-products variation for the same authority. This is from a training of professionals and regulation perspective of policy relevance. Social implications: Contract allocation based on habits rather than rational ground could implicate the waste of resources (tax payers money) as it adventures the matching of the preferences of the public sector (the objective, subject matter, of the procurement) and what the potential supplier offers in its tender. Originality/value: Although the principles for supplier selection are regulated by law they give the contracting authority substantial freedom in designing the scoring rule and in choosing what quality criteria to use. The tension between different objectives and the more general question whether the choices made by authorities reflect rational decision making or institutional inertia together motivate the current study. While the design of the supplier-selection mechanism is an important consideration in procurement practice, it has attracted relatively little attention from the academic community.</p