Characterisation of organomineral fertilisers derived from nutrient-enriched biosolids granules

Organomineral fertilisers (OMFs) were produced by coating biosolids granules with urea and potash. Two OMF formulations with N : P2O5 : K2O compositions: 10 : 4 : 4 (OMF10) and 15 : 4 : 4 (OMF15) were developed for application in grassland and arable crops. Routine fertiliser analyses were conducted on four batches of OMF and biosolids granules and compared with a sample of urea to determine key physical and chemical properties of the materials which affect handling and spreading, soil behaviour, and fertiliser value. Bulk and particle densities were in the range of 608 to 618 kg m−3, and 1297 to 1357 kg m−3, respectively. Compression tests showed that OMF particles undergo deformation followed by multiple failures without disintegration of the granules when vertical load was applied. Static particle strength was between 1.18 and 4.33 N mm−2 depending on the particle diameter. The use of a model for fertiliser particle distribution studies showed that OMF granules should be between 1.10 and 5.50 mm in diameter with about 80% of the particles in the range of 2.25 to 4.40 mm to enable application at 18 m tramline spacing. This research utilises novel technology to improve the fertiliser value of biosolids, reduce disposal costs, and deliver a range of environmental benefits associated with recycling

Tube-side mass transfer for hollow fibre membrane contactors operated in the low Graetz range

Transformation of the tube-side mass transfer coefficient derived in hollow fibre membrane contactors (HFMC) of different characteristic length scales (equivalent diameter and fibre length) has been studied when operated in the low Graetz range (Gz<10). Within the low Gz range, mass transfer is generally described by the Graetz problem (Sh=3.67) which assumes that the concentration profile comprises a constant shape over the fibre radius. In this study, it is experimentally evidenced that this assumption over predicts mass transfer within the low Graetz range. Furthermore, within the low Gz range (below 2), a proportional relationship between the experimentally determined mass transfer coefficient (Kov) and the Graetz number has been identified. For Gz numbers below 2, the experimental Sh number approached unity, which suggests that mass transfer is strongly dependent upon diffusion. However, within this diffusion controlled region of mass transfer, tube-side fluid velocity remained important. For Gz numbers above 2, Sh could be satisfactorily described by extension to the Lévêque solution, which can be ascribed to the constrained growth of the concentration boundary layer adjacent to the fibre wall. Importantly this study demonstrates that whilst mass transfer in the low Graetz range does not explicitly conform to either the Graetz problem or classical Lévêque solution, it is possible to transform the experimentally derived overall mass transfer coefficient (Kov) between characteristic length scales (dh and L). This was corroborated by comparison of the empirical relationship determined in this study (Sh=0.36Gz) with previously published studies operated in the low Gz range. This analysis provides important insight for process design when slow tube-side flows, or low Schmidt numbers (coincident with gases) constrain operation of hollow fibre membrane contactors to the low Gz range

Air quality and mental health: evidence, challenges and future directions

Background: Poor air quality is associated with poor health. Little attention is given to the complex array of environmental exposures and air pollutants that affect mental health during the life course. Aims: We gather interdisciplinary expertise and knowledge across the air pollution and mental health fields. We seek to propose future research priorities and how to address them. Method: Through a rapid narrative review, we summarise the key scientific findings, knowledge gaps and methodological challenges. Results: There is emerging evidence of associations between poor air quality, both indoors and outdoors, and poor mental health more generally, as well as specific mental disorders. Furthermore, pre-existing long-term conditions appear to deteriorate, requiring more healthcare. Evidence of critical periods for exposure among children and adolescents highlights the need for more longitudinal data as the basis of early preventive actions and policies. Particulate matter, including bioaerosols, are implicated, but form part of a complex exposome influenced by geography, deprivation, socioeconomic conditions and biological and individual vulnerabilities. Critical knowledge gaps need to be addressed to design interventions for mitigation and prevention, reflecting ever-changing sources of air pollution. The evidence base can inform and motivate multi-sector and interdisciplinary efforts of researchers, practitioners, policy makers, industry, community groups and campaigners to take informed action. Conclusions: There are knowledge gaps and a need for more research, for example, around bioaerosols exposure, indoor and outdoor pollution, urban design and impact on mental health over the life course.Natural Environment Research Council (NERC): NE/V002171/1; Engineering and Physical Sciences Research Council (EPSRC): EP/V052462/1; EP/W001411/1; EP/T003189/

Pyogenic spondylitis

Pyogenic spondylitis is a neurological and life threatening condition. It encompasses a broad range of clinical entities, including pyogenic spondylodiscitis, septic discitis, vertebral osteomyelitis, and epidural abscess. The incidence though low appears to be on the rise. The diagnosis is based on clinical, radiological, blood and tissue cultures and histopathological findings. Most of the cases can be treated non-operatively. Surgical treatment is required in 10–20% of patients. Anterior decompression, debridement and fusion are generally recommended and instrumentation is acceptable after good surgical debridement with postoperative antibiotic cover

Removal of ammoniacal nitrogen from landfill leachate by irrigation onto vegetated treatment planes

Leachate is a contaminated liquor resulting from the disposal of solid and liquid wastes at landfill sites that must be treated before discharge. Vegetated leachate treatment planes have been used at landfill sites in the UK but have received little scientific attention. This paper describes studies of model leachate treatment planes with a focus on the removal of ammoniacal nitrogen (NH3-N). Small-scale and field-scale experimental treatment planes were constructed, filled with clay loam soil and vegetated with grass (Agrostis stolonifera). Landfill leachate was applied at hydraulic loading rates ranging from 17-217 l/m2/d. An exponential relationship was used to characterise the pattern of NH3-N removal. No relationship was observed between the hydraulic loading rate and the NH3-N removal rate constants (R2 = 0.0039). The daily specific NH3 -N mass removal rate was found to be linearly related to the NH3 -N concentration at the start of that day of treatment (R2 = 0.35). Possible causes of variation in the rate of NH3-N removal between experiments are discussed. A simple inorganic nitrogen balance indicated that the mass of NH3-N and NO2-N removed was not accounted for by NO3-N production. Explanations for this apparent nitrogen deficit are discussed

Development of organomineral fertilisers derived from nutrient-enriched biosolids granules: product specification

A technique was developed to produce organomineral fertilisers (OMF) using biosolids granules coated with urea and potash. Two OMF formulations with the following N:P2O5:K2O compositions: 10:4:4 (OMF10) and 15:4:4 (OMF15) were developed for application in grassland and arable crops. Routine fertiliser analyses were conducted on OMF and biosolids samples, and compared with a sample of urea to determine key physical and chemical properties of the materials which affect handling and spreading, soil behaviour and fertiliser value. Bulk and particle densities were in the range of 608 to 618kg m-3, and 1297 to 1357kg m-3 respectively. Compression tests showed that OMF particles undergo deformation followed by multiple failures without disintegration of the granules when vertical load was applied. This behaviour was attributed to the moisture content (�15% w w-1) and the organic nature of the material. Static particle strength was between 1.14 and 6.31 Nmm-2 depending on the particle diameter. The use of a model for fertiliser particle distribution studies showed that OMF granules should be between 1.10 and 5.50mm in diameter with about 80% of the particles in the range of 2.25 to 4.40mm to enable application at 18m tramline spacing. This research is novel as it utilises technology to improve fertiliser value of biosolids to increase usage by farmers, reduce disposal costs and deliver the range of environmental benefits associated with recycling