Seasonally loaded waste stabilisation ponds: a novel application for intermittent discharge

This research examined the use of a single facultative pond for treatment of an intermittent discharge from a UK campsite. The system was monitored over an 11-month period to determine the optimum time for discharge in terms of quality standards. The results showed that based on organic strength, discharge was possible in winter between November and March but February was the optimum to meet nutrient and suspended solids requirements. The pond showed rapid acclimatisation to the influent wastewater, with biochemical oxygen demand removal rates during the filling period of around 60 kg ha?1 day?1 and removal efficiencies of ?95% after maturation. The system proved simple to operate. A major design factor is the requirement for storage of net incoming precipitation, which may provide dilution of residual pollutants but requires additional system capacity.<br/

Operation and recovery of a seasonally-loaded UK waste stabilisation pond system

An intermittent discharge waste stabilisation pond system was trialled for treatment of a seasonal wastewater load from a campsite. The system showed rapid acclimatisation to incoming load, with chlorophyll-a exceeding 700 mg l?1 within 2 weeks and filtered and unfiltered effluent biochemical oxygen demand below 20 and 30 mg l?1 respectively. Good performance continued for some weeks, after which photosynthetic oxygenation capacity in the first pond was seriously impaired by a shock loading believed to include fatty material. Inflow to the system was suspended and a surface film was broken up, after which the pond recovered within an 8-day period. Laboratory experiments indicated that interventions such as artificial aeration and dilution with effluent had no beneficial effect although mixing may have increased the rate of recovery

Fundamental optical and magneto-optical constants of Co/Pt and CoNi/Pt multilayered films

A study has been made of the optical and magneto-optical properties of several Co/Pt and CoNi/Pt multilayered films that were fabricated by magnetron sputter deposition. Spectroscopic rotating analyzer ellipsometry and Kerr polarimetry were carried out to determine the fundamental optical and magneto-optical constants over the spectral range 320¿860 nm. The constants determined were the complex refractive index and the first-order magneto-optic Voigt parameter. A total of seven films were examined and excellent reproducibility was observed in the measured material constants. These have been used to discuss the spectral dependence of the figure-of-merit, for each material, associated with the detection of the polar Kerr effect

Predicting Broccoli Development: I. Development Is Predominantly Determined By Temperature Rather Than Photoperiod

Predictive models of broccoli (Brassica oleracea L. var. italica Plenck) ontogeny will aid farmers who need to forecast changes in crop maturity arising from variable climatic conditions so that their forward marketing arrangements can match their anticipated supply. The objective of this study was to quantify the temperature and photoperiod responses of development in a sub-tropical environment from emergence to floral initiation (EFI), and from floral initiation to harvest maturity (FIHM). Three cultivars, ('Fiesta', 'Greenbelt' and 'Marathon') were sown on eight dates from 11 March to 22 May 1997 and grown under natural and extended (16 h) photoperiods at Gatton College, south-east Queensland, under non-limiting conditions of water and nutrient supply. Climatic data, dates of emergence, floral initiation and harvest maturity were obtained. The estimated base (Tbase) and optimum (Topt) temperatures of 0 and 20 degrees C, respectively were consistent across cultivars, but thermal time requirements were cultivar specific. Differences in thermal time between cultivars during FIHM were small and of little practical importance, but differences in thermal time during EFI were large. Sensitivity to photoperiod and solar radiation was low in the three cultivars used. When the thermal time models were tested on independent data for five cultivars ('Fiesta', 'Greenbelt', 'Marathon', 'CMS Liberty' and 'Triathlon') grown as commercial crops over two years, they adequately predicted floral initiation and harvest maturity

A new direction for tackling phosphorus inefficiency in the UK food system

Publication history: Accepted - 3 April 2022; Published online - 25 April 2022The UK food system is reliant on imported phosphorus (P) to meet food production demand, though inefficient use and poor stewardship means P is currently accumulating in agricultural soils, wasted or lost with detrimental impacts on aquatic environments. This study presents the results of a detailed P Substance Flow Analysis for the UK food system in 2018, developed in collaboration with industry and government, with the key objective of highlighting priority areas for system interventions to improve the sustainability and resilience of P use in the UK food system. In 2018 the UK food system imported 174.6 Gg P, producing food and exportable commodities containing 74.3 Gg P, a P efficiency of only 43%. Three key system hotspots for P inefficiency were identified: Agricultural soil surplus and accumulation (89.2 Gg P), loss to aquatic environments (26.2 Gg P), and waste disposal to landfill and construction (21.8 Gg P). Greatest soil P accumulation occurred in grassland agriculture (85% of total accumulation), driven by loadings of livestock manures. Waste water treatment (12.5 Gg P) and agriculture (8.38 Gg P) account for most P lost to water, and incineration ashes from food system waste (20.3 Gg P) accounted for nearly all P lost to landfill and construction. New strategies and policy to improve the handling and recovery of P from manures, biosolids and food system waste are therefore necessary to improve system P efficiency and reduce P accumulation and losses, though critically, only if they effectively replace imported mineral P fertilisers.This paper was produced as part of the RePhoKUs project (The role of phosphorus in the sustainability and resilience of the UK food system) funded by BBSRC, ESRC, NERC, and the Scottish Government under the UK Global Food Security research programme (Grant No. BB/R005842/1)

Origin of Life

The evolution of life has been a big enigma despite rapid advancements in the fields of biochemistry, astrobiology, and astrophysics in recent years. The answer to this puzzle has been as mind-boggling as the riddle relating to evolution of Universe itself. Despite the fact that panspermia has gained considerable support as a viable explanation for origin of life on the Earth and elsewhere in the Universe, the issue remains far from a tangible solution. This paper examines the various prevailing hypotheses regarding origin of life like abiogenesis, RNA World, Iron-sulphur World, and panspermia; and concludes that delivery of life-bearing organic molecules by the comets in the early epoch of the Earth alone possibly was not responsible for kick-starting the process of evolution of life on our planet.Comment: 32 pages, 8 figures,invited review article, minor additio

Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths

We review observations of several classes of neutron-star-powered outflows: pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe interacting directly with interstellar medium (ISM), and magnetar-powered outflows. We describe radio, X-ray, and gamma-ray observations of PWNe, focusing first on integrated spectral-energy distributions (SEDs) and global spectral properties. High-resolution X-ray imaging of PWNe shows a bewildering array of morphologies, with jets, trails, and other structures. Several of the 23 so far identified magnetars show evidence for continuous or sporadic emission of material, sometimes associated with giant flares, and a few possible "magnetar-wind nebulae" have been recently identified.Comment: 61 pages, 44 figures (reduced in quality for size reasons). Published in Space Science Reviews, "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release

Calculating the economic cost of mitigating GHG emissions from UK dairy farms by anaerobic digestion of slurry

This study analyses anaerobic digestion (AD) as a renewable energy technology by quantifying the emissions avoided and the cost incurred in the process. The quantitative model developed and demonstrated uses basic farm information to evaluate dairy farms from an environmental and economic perspective. Based on the cost of installing and operating an anaerobic digester and the emissions avoided using this technology, the marginal carbon abatement cost (MAC) is calculated. The MAC thus obtained is used to analyse current policy incentives thereby bridging the gap between the environmental impacts, the economic (dis)incentives and sustainable farming practices

Residual stress distribution in a functionally graded alumina-silicon carbide material

Functionally graded ceramic structures have a range of potential applications as they enable the exploitation of two ceramic materials with very different properties, such as coefficient of thermal expansion. We report the microstructural investigation of a novel functionally graded structure for alumina and silicon carbide with systematically varied composition. Stresses in the structure have been modelled analytically and by finite element modelling, and are consistent with fluorescence microscopy measurements of residual stress in the structure

Establishing an energy balance for crop-based digestion

The paper examines methods for calculating energy surpluses through anaerobic digestion and gives some examples of the practical application of these in crop-based systems. The surplus energy is the balance between that produced as a usable energy source and that used in crop production, conversion of the biomass into biogas, and conversion of biogas into a usable form: these are the direct energy inputs. The energy balance also takes into account the embedded energy used in the construction of machinery and buildings and for their repair and maintenance: the indirect energy inputs. The area of land available for fuel production is finite and therefore the energy yield is best considered on a per hectare basis. This allows comparison of energy conversion efficiency where the biomass yield for that area may vary depending on a range of inputs, e.g. rate of fertiliser application or irrigation requirements. It also allows direct comparison between different crop species or varieties within a single species. For an accurate energy balance analysis direct and indirect energy requirements have to be established for all the stages in the crop-based energy production cycl