Roles of acid-producing bacteria in anaerobic digestion of waste activated sludge

Three acid-producing strains, AFB-1, AFB-2 and AFB-3, were isolated during this study, and their roles in anaerobic digestion of waste activated sludge (WAS) were evaluated. Data of 16S rRNA method showed that AFB-1 and AFB-2 were Bacillus coagulans, and AFB-3 was Escherichia coli. The removal in terms of volatile solids (VS) and total chemical oxygen demand (TCOD) was maximized at 42.7% and 44.7% by inoculating Bacillus coagulans AFB-1. Besides, the optimal inoculum concentration of Bacillus coagulans AFB-1 was 30% (v/v). Solubilization degree experiments indicated that solubilization ratios (SR) of WAS reached 20.8%±2.2%, 17.7%±1.48%, and 11.1%±1.53%. Volatile fatty acids (VFAs) concentrations and compositions were also explored with a gas chromatograph. The results showed that VFAs improved by 98.5%, 53.0% and 11.6% than those of the control, respectively. Biochemical methane potential (BMP) experiments revealed that biogas production increased by 90.7% and 75.3% when inoculating with Bacillus coagulans AFB-1 and AFB-2. These results confirmed that the isolated acid-producing bacteria, especially Bacillus coagulans, was a good candidate for anaerobic digestion of WAS.

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An extraction-assay system: Evaluation on flavonols in plant resistance to Pb and Cd by supercritical extraction-gas chromatography

In this research, supercritical carbon dioxide extraction (SFE) showed better extraction effect when compared with Solid- liquid extraction (SLE), Soxhlet extraction (SE) and Ultrasonic extraction (UE), not only in the rate but also the time. The comparison among these three extraction modifiers, including acetone, ethanol and methanol demonstrated that ethanol was preferred to SFE due to its high extraction effect and low toxicology. In addition, parameter of SFE, influence of temperature and pressure were investigated, and the best extraction effect was achieved at the optima conditions, temperature of 40°C and the pressure of 35 MPa. Thus, SFE is a highly effective method for flavonols extraction, requiring minimum energy and producing non-toxic byproduct. SFE-GC system is applied for the evaluation on flavonols that plays a key role in plant resistance to heavy metal, with its content and synthetase gene expression significantly increasing in plant when threatened by heavy metal. Besides, results indicated that flavonols can improve plant resistance to oxidative stress by quenching the redundant ROS in matrix.

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Efficient photoelectrochemical oxidation of rhodamine B on metal electrodes without photocatalyst or supporting electrolyte

We designed photoelectrochemical cells to achieve efficient oxidation of rhodamine B (RhB) without the need for photocatalyst or supporting electrolyte. RhB, the metal anode/cathode, and O₂ formed an energy-relay structure, enabling the efficient formation of O ₂ ^– species under ultraviolet illumination. In a single-compartment cell (S cell) containing a titanium (Ti) anode, Ti cathode, and 10 mg·mL^–1 RhB in water, the zero-order rate constant of the photoelectrochemical oxidation (k_PEC) of RhB was 0.049 mg·L^–1·min^–1, while those of the photochemical and electrochemical oxidations of RhB were nearly zero. k_PEC remained almost the same when 0.5 mol·L^–1 Na₂SO₄ was included in the reactive solution, regardless of the increase in the photocurrent of the S cell. The k_PEC of the illuminated anode compartment in the two-compartment cell, including a Ti anode, Ti cathode, and 10 mg·mL^–1 RhB in water, was higher than that of the S cell. These results support a simple, eco-friendly, and energysaving method to realize the efficient degradation of RhB.

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Algal biomass derived biochar anode for efficient extracellular electron uptake from <Emphasis Type="Italic">Shewanella oneidensis</Emphasis> MR-1

The development of cost-effective and highly efficient anode materials for extracellular electron uptake is important to improve the electricity generation of bioelectrochemical systems. An effective approach to mitigate harmful algal bloom (HAB) is mechanical harvesting of algal biomass, thus subsequent processing for the collected algal biomass is desired. In this study, a low-cost biochar derived from algal biomass via pyrolysis was utilized as an anode material for efficient electron uptake. Electrochemical properties of the algal biochar and graphite plate electrodes were characterized in a bioelectrochemical system (BES). Compared with graphite plate electrode, the algal biochar electrode could effectively utilize both indirect and direct electron transfer pathways for current production, and showed stronger electrochemical response and better adsorption of redox mediators. The maximum current density of algal biochar anode was about 4.1 times higher than graphite plate anode in BES. This work provides an application potential for collected HAB to develop a cost-effective anode material for efficient extracellular electron uptake in BES and to achieve waste resource utilization.

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Inverse uncertainty characteristics of pollution source identification for river chemical spill incidents by stochastic analysis

Identifying source information after river chemical spill occurrences is critical for emergency responses. However, the inverse uncertainty characteristics of this kind of pollution source inversion problem have not yet been clearly elucidated. To fill this gap, stochastic analysis approaches, including a regional sensitivity analysis method, identifiability plot and perturbation methods, were employed to conduct an empirical investigation on generic inverse uncertainty characteristics under a well-accepted uncertainty analysis framework. Case studies based on field tracer experiments and synthetic numerical tracer experiments revealed several new rules. For example, the release load can be most easily inverted, and the source location is responsible for the largest uncertainty among the source parameters. The diffusion and convection processes are more sensitive than the dilution and pollutant attenuation processes to the optimization of objective functions in terms of structural uncertainty. The differences among the different objective functions are smaller for instantaneous release than for continuous release cases. Small monitoring errors affect the inversion results only slightly, which can be ignored in practice. Interestingly, the estimated values of the release location and time negatively deviate from the real values, and the extent is positively correlated with the relative size of the mixing zone to the objective river reach. These new findings improve decision making in emergency responses to sudden water pollution and guide the monitoring network design.

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Coastal dwellers-power against climate change: a place-based perspective on individual and collective engagement in North Frisia

Climate change induces non-linear and unevenly distributed changes, such rising sea levels and extreme weather events that materialise on the regional level and considerably contribute to changes in the social fabric of regions, communities and places. Because of the need for societal responses, an in-depth understanding of individual and collective forms of engagement with climate change is of growing relevance. To contribute to close this gap, this paper applies a place-based approach for investigating how people’s place attachments and meanings inform individual and collective engagement with climate change. As a case study, the district of North Frisia (Germany) was chosen, a region between climate-change vulnerability and renewable-energy potential. Qualitative interviews and a household survey with coastal dwellers of the municipality of Reußenköge have been conducted, a group discussion with the Country Youth (Landjugend) and further interviews with experts from government, companies and associations spread over North Frisia and in Kiel. The results reveal two main findings: firstly, place-dependent attachments and meanings play a pivotal role for understanding people’s engagement with climate change, and secondly, the behavioural dimension of engagement involves diverse adaptation and mitigation measures adopted on individual and collective level. In sum, the findings conceptually and empirically reveal the importance of memories, experiences, knowledge and creativity for how people engage with climate change, but also exhibit the importance of policies mobilising community-based actions.     

The regional framing of climate change: towards a place-based perspective on regional climate change perception in north Frisia

Numerous studies have begun to tackle the social and cultural dimensions of perceiving and framing climate change. Scholars from geography and environmental psychology in particular have started to highlight the importance of so-called place-based approaches to studying regional and local framings of climate change. This paper stands in this tradition. It reports on findings derived from a nationwide survey of perceptions of and reactions to extreme weather events and interviews conducted with inhabitants of three islands in the coastal region of North Frisia (Germany). Coastal dwellers understand climate change through the lens of local and regional experiences of meteorological phenomena, seasonal changes, knowledge of the sea, and changes in local flora and fauna. Our detailed ecolinguistic analysis revealed six prevailing conceptual metaphors: Climate change is an enemy, preventing climate change is fight/war, climate change is punishment for human sins, climate change is overheating/heat, climate change is hot air/hoax and climate change is eco-dictatorship. These metaphors were used to make sense of climate change at the regional level and provide insights into place-based social and cultural conceptualisations of climate change. An understanding of these meanings should feed into developing more grounded climate change adaptation and mitigation strategies in coastal regions.     

Fossil bog soils (‘<Emphasis Type="Italic">dwog</Emphasis> horizons’) and their relation to Holocene coastal changes in the Jade Weser region,southern North Sea,Germany

After the deceleration of the postglacial marine transgression, the German North Sea coast was subject to deposition of a complex pattern of subtidal to terrestrial facies. This study aims at reconstructing these facies changes in the ‘Land Wursten’ region (Lower Saxony) by focussing on so-called dwog horizons (incipient soil horizons of the pre-engineered salt marshes). We explore their implications for relative sea-level reconstructions and their indication for early settlement activities. Archive drilling data (1960, provided by the ‘Landesamt für Bergbau, Energie und Geologie’) were analysed to create five high-resolution stratigraphic cross sections. Three new drilling records were subjected to sedimentological and microfaunal investigations and interpreted to verify and calibrate the archive data. Two dwog horizons were found and ¹⁴C-AMS dated. We found basal salt marsh deposits inundated by a high-energy event and covered by tidal flat sediments. The thick tidal flat unit is again overlain by salt marsh deposits indicating the transition from a shallow marine to a terrestrial environment where dwogs were developed and covered by episodic marine incursions. The ages of the dwogs (1128–969 cal BC; cal AD 1426–1467) do not correlate with known layers of adjacent settlement sites and are critically discussed. However, we show that they correlate with phases of stagnant regional relative sea level (RSL) and can be used as RSL indicators. The combined archive and modern data provide valuable information for the RSL reconstruction and palaeoenvironmental changes. However, further research is recommended to accomplish more detailed information about coastal response during the Holocene sea-level changes and implications for settlement dynamics.     

A combined coastal protection,realignment and wetland restoration scheme in the southern Baltic: planning process,public information and participation

Markgrafenheide-Hütelmoor covers a total area of 1000 ha (about 490 ha are coastal moor) and a coastline of about 6 km. This touristy area belongs to the city of Rostock in Germany. As response to sea level rise and heavy coastal erosion, the small seaside resort Markgrafenheide received a comprehensive storm surge protection until 2006. Subsequently, the adjacent Hütelmoor was flooded with the aim to restore it as a brackish coastal moor. Coastal protection measures at the Baltic Sea coastline were abandoned to enable natural dynamics, a coastal realignment and salt water intrusions. The entire process until full implementation took 14 years and was associated with very problematic public participation and a strong local polarization. Based on a literature and media review, two surveys, and expert interviews we retrospectively document and analyse the planning process with focus on public information, perception and participation. The local population and holidaymakers did not perceive coastal changes and if, did not associate them with climate change. Interviewees remembered single storm surges, but felt save from it and sea level rise was not perceived as a threat. 89% said that they feel insufficiently informed about the combined coastal protection wetland restoration measure, but did not use the offered information possibilities. 81% had their information from newspapers and freely distributed advertisers. It seems that insufficient information was the major reason for the problems with local acceptance and public participation. The media played a dominating role. The decline of traditional newspapers and the growths of free advertisers seemed to have a negative impact on quality of information and favoured a polarization. Additionally, we discuss local specifics like the cultural background (GDR history), traditions, frustration and the relatively old population and their role in public participation. We strongly promote a pro-active and long-term information and public relation strategy.     

Recent shoreline evolution and beach erosion along the central Adriatic coast of Italy: the case of Molise region

A study on the modern dynamics and shoreline changes from 1954 to 2014 of the Molise coast (central Adriatic Sea) has been carried out. Short to long-term shoreline changes and associated surface area variations have been assessed in GIS environment for the study coast, subdivided in nine coastal segments (S1-S9), by using 100-m regularly spaced transects. In addition, the possible influence of natural and anthropogenic factors, especially of climatic variability and engineered shoreline defense structures, has been investigated. The Molise coast has experienced notable long-term erosion (period 1054-2014) that caused an overall coastal land loss of approximately 940,000 m². Erosion was, yet, limited to coastal segments S1 and S7, nearest to the mouths of major rivers, namely Trigno and Biferno, while the major part of the study coast has remained essentially stable or even advanced. Increased shoreline protection by defense structures has generally favoured shoreline stability and frequently generated shoreline advance, except for segments S1 and S7. Observed differences in shoreline change rates over time at the decadal to interannual scale, have not find a response in the analysis of available data on meteo-marine conditions of the Molise coast and climate variability indices, pointing out the need to improve knowledge on meteomarine conditions and on climatic variability forcing of the study area. From 2004 to 2014, the Molise shoreline remained essentially stable. Nonetheless, most recent shoreline changes (period 2011-2014) and modern shoreline dynamics indicate that erosion has become more widespread, involving at least part of segments S2-S3 and S8-S9, located south of the river mouth segments. The localized long-term shoreline retreat and most recent shoreline erosion appear to be primarily related to channel adjustments of the Biferno and Trigno rivers that occurred since the 1950s under the control of human interventions on the rivers, especially the construction respectively of a dam and a check dam along their lower courses, that trap of most of their solid load, affecting so adversely the sediment budget of the river mouths areas and adjacent beaches. Overall data acquired on the recent shoreline evolution and modern shoreline dynamics of the Molise coast and on related causal factors provide a good basic knowledge for regional coastal management purposes, and for further scientific purposes. Particularly, they suggest the opportunity to deepen a number of aspects such as the relationship between the coast and river catchments feeding it, the possible influences on the Molise shoreline dynamics of the neighbouring coasts, the efficiency/obsolescence of defense structures and the present-day vulnerability to coastal erosion of the Molise coast.