Investigating biodiversity trajectories using scenarios – Lessons from two contrasting agricultural landscapes

Agriculture is the major land use at a global scale. In addition to food production, multifunctionality of landscapes, including values and ecosystem services like biodiversity, recreation and culture, is now focus for management. This study explores how a scenario approach, involving different stakeholders, may help to improve landscape management for biodiversity conservation. Local farmers and executives at the County Administrative Board were invited to discuss rural development and conditions for farmland biodiversity in two Swedish landscapes. The potential biodiversity for three future land use scenarios for the two landscapes was discussed: nature conservation, outdoor recreation and energy production, and compared with current and historical landscapes in each region.Analyses of habitat areas, connectedness and landscape diversity suggested that the energy and recreation scenarios had a negative impact on farmland biodiversity, whereas the nature conservation scenario, the current and historically reconstructed landscapes had a higher potential for biodiversity. The farmers appreciated the nature conservation scenario, but also the energy production scenario and they highlighted the need of increased subsidies for management of biodiversity. The farmers in the high production area were less interested in nature quality per se. The executives had similar opinions as the farmers, but disagreed on the advantages with energy production, as this would be in conflict with the high biodiversity and recreational values. The local physical and socio-economical conditions differ between landscapes and potentially shaped the stakeholders emotional attachment to the local environment, their opinions and decisions on how to manage the land. We stress the importance of incorporating local knowledge, visions and regional prerequisites for different land uses in conservation, since site and landscape specific planning for biodiversity together with a flexible subsidy system are necessary to reach the conservation goals within EU.     

Field evaluation of resistivity sensors for in situ moisture measurement in a bioreactor landfill

The ability of resistance-based sensors to measure in situ waste moisture content in a landfill was examined. One hundred and thirty-five resistance-based sensors were installed in a leachate recirculation well field at a bioreactor landfill in Florida, US. The performance of these sensors was studied for a period of over 6 years. The sensors were found to respond to an increase in moisture resulting from leachate recirculation. It was observed that 78% of sensors worked successfully in the field during the study period. The initial spatial average moisture content determined by the sensor readings (using a laboratory-derived calibration) was 42.8% compared to 23% from gravimetric readings. Eighteen sensors (13%) showed that they were saturated before liquid addition, and no change in moisture content was observed in these sensors during the study period. Laboratory-derived calibration methods resulted in an over-estimation of moisture content. An alternate field-calibration method, where wetted sensor output was assumed equal to the average of gravimetric measurements for wet samples, was evaluated. The final spatial average moisture contents were 64.2% and 44.4% for the laboratory-derived and field-derived calibration methodologies, respectively, compared to 45% measured gravimetrically from excavated waste samples. When moisture content was determined using a mass balance approach, the result was 34.6%. The results suggest that when appropriately calibrated, resistivity-based sensors can be used to obtain a reasonably accurate estimate of local moisture content. However, caution should be taken to extend the moisture content values that are representative of waste surrounding the sensors to estimate the overall moisture content on the landfill-wide scale.     

3D geomechanical modelling for CO2 geologic storage in the Dogger carbonates of the Paris Basin

CO₂ injection into a depleted hydrocarbon field or aquifer may give rise to a variety of coupled physical and chemical processes. During CO₂ injection, the increase in pore pressure can induce reservoir expansion. As a result the in situ stress field may change in and around the reservoir. The geomechanical behaviour induced by oil production followed by CO₂ injections into an oil field reservoir in the Paris Basin has been numerically modelled. This paper deals with an evaluation of the induced deformations and in situ stress changes, and their potential effects on faults, using a 3D geomechanical model. The geomechanical analysis of the reservoir–caprock system was carried out as a feasibility study using pressure information in a “one way” coupling, where pressures issued from reservoir simulations were integrated as input for a geomechanical model. The results show that under specific assumptions the mechanical effects of CO₂ injection do not affect the mechanical stability of the reservoir–caprock system. The ground vertical movement at the surface ranges from ?2 mm during oil production to +2.5 mm during CO₂ injection. Furthermore, the changes in in situ stresses predicted under specific assumptions by geomechanical modelling are not significant enough to jeopardize the mechanical stability of the reservoir and caprock. The stress changes issued from the 3D geomechanical modelling are also combined with a Mohr–Coulomb analysis to determine the fault slip tendency. By integrating the stress changes issued from the geomechanical modelling into the fault stability analysis, the critical pore pressure for fault reactivation is higher than calculated for the fault stability analysis considering constant horizontal stresses.     

Processing of poultry feathers by alkaline keratin hydrolyzing enzyme from Serratia sp. HPC 1383

The present study describes the production and characterization of a feather hydrolyzing enzyme by Serratia sp. HPC 1383 isolated from tannery sludge, which was identified by the ability to form clear zones around colonies on milk agar plates. The proteolytic activity was expressed in terms of the micromoles of tyrosine released from substrate casein per ml per min (U/mL min). Induction of the inoculum with protein was essential to stimulate higher activity of the enzyme, with 0.03% feathermeal in the inoculum resulting in increased enzyme activity (45 U/mL) that further increased to 90 U/mL when 3 d old inoculum was used. The highest enzyme activity, 130 U/mL, was observed in the presence of 0.2% yeast extract. The optimum assay temperature and pH for the enzyme were found to be 60 °C and 10.0, respectively. The enzyme had a half-life of 10 min at 60 °C, which improved slightly to 18 min in presence of 1 mM Ca²⁺. Inhibition of the enzyme by phenylmethyl sulfonyl fluoride (PMSF) indicated that the enzyme was a serine protease. The enzyme was also partially inhibited (39%) by the reducing agent β-mercaptoethanol and by divalent metal ions such as Zn²⁺ (41% inhibition). However, Ca²⁺ and Fe²⁺ resulted in increases in enzyme activity of 15% and 26%, respectively. The kinetic constants of the keratinase were found to be 3.84 μM (K_m) and 108.7 μM/mL min (V_max). These results suggest that this extracellular keratinase may be a useful alternative and eco-friendly route for handling the abundant amount of waste feathers or for applications in other industrial processes.     

19th century London dust-yards: A case study in closed-loop resource efficiency

The material recovery methods used by dust-yards in early 19th century London, England and the conditions that led to their development, success and decline are reported. The overall system developed in response to the market value of constituents of municipal waste, and particularly the high coal ash content of household ‘dust’. The emergence of lucrative markets for ‘soil’ and ‘breeze’ products encouraged dust-contractors to recover effectively 100% of the residual wastes remaining after readily saleable items and materials had been removed by the thriving informal sector. Contracting dust collection to the private sector allowed parishes to keep the streets relatively clean, without the need to develop institutional capacity, and for a period this also generated useful income. The dust-yard system is, therefore, an early example of organised, municipal-wide solid waste management, and also of public–private sector participation. The dust-yard system had been working successfully for more than 50 years before the Public Health Acts of 1848 and 1875, and was thus important in facilitating a relatively smooth transition to an institutionalised, municipally-run solid waste management system in England. The dust-yards can be seen as early precursors of modern materials recycling facilities (MRFs) and mechanical–biological treatment (MBT) plants; however, it must be emphasised that dust-yards operated without any of the environmental and occupational health considerations that are indispensable today. In addition, there are analogies between dust-yards and informal sector recycling systems currently operating in many developing countries.     

Anaerobic biodegradation of cellulosic material: Batch experiments and modelling based on isotopic data and focusing on aceticlastic and non-aceticlastic methanogenesis

Utilizing stable carbon isotope data to account for aceticlastic and non-aceticlastic pathways of methane generation, a model was created to describe laboratory batch anaerobic decomposition of cellulosic materials (office paper and cardboard). The total organic and inorganic carbon concentrations, methane production volume, and methane and CO₂ partial pressure values were used for the model calibration and validation. According to the fluorescent in situ hybridization observations, three groups of methanogens including strictly hydrogenotrophic methanogens, strictly aceticlastic methanogens (Methanosaeta sp.) and Methanosarcina sp., consuming both acetate and H₂/H₂CO₃ as well as acetate-oxidizing syntrophs, were considered. It was shown that temporary inhibition of aceticlastic methanogens by non-ionized volatile fatty acids or acidic pH was responsible for two-step methane production from office paper at 35 °C where during the first and second steps methane was generated mostly from H₂/H₂CO₃ and acetate, respectively. Water saturated and unsaturated cases were tested. According to the model, at the intermediate moisture (150%), much lower methane production occurred because of full-time inhibition of aceticlastic methanogens. At the lowest moisture, methane production was very low because most likely hydrolysis was seriously inhibited. Simulations showed that during cardboard and office paper biodegradation at 55 °C, non-aceticlastic syntrophic oxidation by acetate-oxidizing syntrophs and hydrogenotrophic methanogens were the dominant methanogenic pathways.     

Utilization of molasses spentwash for production of bioplastics by waste activated sludge

Present study describes the treatment of molasses spentwash and its use as a potential low cost substrate for production of biopolymer polyhydroxybutyrate (PHB) by waste activated sludge. Fluorescence microscopy revealed the presence of PHB granules in sludge biomass which was further confirmed by fourier transform-infra-red spectroscopy (FT-IR) and ¹³C nuclear magnetic resonance (NMR). The processing of molasses spentwash was carried out for attaining different ratios of carbon and nitrogen (C:N). Highest chemical oxygen demand (COD) removal and PHB accumulation of 60% and 31% respectively was achieved with raw molasses spentwash containing inorganic nitrogen (C:N ratio = 28) followed by COD removal of 52% and PHB accumulation of 28% for filtered molasses containing inorganic nitrogen (C:N ratio = 29). PHB production yield (Y_p/s) was highest (0.184 g g^?1 COD consumed) for deproteinized spentwash supplemented with nitrogen. In contrast, the substrate consumption and product formation were higher in case of raw spentwash. Though COD removal was lowest from deproteinized spentwash, evaluation of kinetic parameters suggested higher rates of conversion of available carbon to biomass and PHB. Thus the process provided dual benefit of conversion of two wastes viz. waste activated sludge and molasses spentwash into value-added product-PHB.     

Adsorption of Geosmin and MIB on Activated Carbon Fibers–Single and Binary Solute System

The adsorption of two taste- and odor-causing compounds, namely MIB (2-methyl isoborneol—C₁₁H₂₀O) and geosmin (C₁₂H₂₂O) on activated carbon was investigated in this study. The impact of adsorbent pore size distribution on adsorption of MIB and geosmin was evaluated through single solute and multicomponent adsorption of these compounds on three types of activated carbon fibers (ACFs) and one granular activated carbon (GAC). The ACFs (ACC-15, ACC-20, and ACC-25) with different degrees of activation had narrow pore size distributions and specific critical pore diameters whereas the GAC (F-400) had a wider pore size distribution and lesser microporosity. The effect of the presence of natural organic matter (NOM) on MIB and geosmin adsorption was also studied for both the single solute and binary systems. The Myers equation was used to evaluate the single solute isotherms as it converges to Henry’s law at low coverage and also serves as an input for predicting multicomponent adsorption. The single solute adsorption isotherms fit the Myers equation well and pore size distribution significantly influenced adsorption on the ACFs and GAC. The ideal adsorbed solute theory (IAST), which is a well-established thermodynamic model for multicomponent adsorption, was used to predict the binary adsorption of MIB and geosmin. The IAST predicted well the binary adsorption on the ACFs and GAC. Binary adsorption isotherms were also conducted in the presence of oxygen (oxic) and absence of oxygen (anoxic). There were no significant differences in the binary isotherm between the oxic and anoxic conditions, indicating that adsorption was purely through physical adsorption and no oligomerization was taking place. Binary adsorptions for the four adsorbents were also conducted in the presence of humic acid to determine the effect of NOM and to compare with IAST predictions. The presence of NOM interestingly resulted in deviation from IAST behavior in case of two adsorbents, ACC-15 and F-400.