Towards the selection of a produced water enrichment for biological gas hydrate inhibitors

Economic concerns associated with the recovery of non-conventional hydrocarbon reserves include unexpected ice as well as ice-like gas hydrate formation. Antifreeze proteins (AFPs) inhibit ice growth, and experiments with fish, plant, and insect AFPs have shown promise of effective gas hydrate inhibition in lab-scale experiments. If produced on an industrial scale, AFPs could provide a more environmentally friendly alternative to kinetic inhibitors, but a large-scale production of these AFPs is not currently feasible. We believe that these difficulties could be surmounted by the production of microbial AFPs, but to date, only a few such proteins have been identified and purified, and none of these are associated with hydrocarbon reserves. Here, we have used ice-affinity and freeze-thaw stress to select microbes derived from oil and gas formation water, or produced water, as a source of anaerobic microbial communities. Ice-affinity successfully incorporated anaerobic bacteria under aerobic conditions, and the mixed culture had ice-associating properties. Under these conditions, ice-affinity selection does not result in cultivatable isolates, but similar, cultivable microbes were obtained following freeze-thaw selection under anaerobic conditions. Since these mixed cultures inhibited the growth of ice crystals, they also have the potential to inhibit hydrate growth. Overall, freeze-thaw selection provides a promising first step towards the isolation of microbes capable of the inhibition of ice and gas hydrate growth, for possible application for energy exploration and recovery at high-latitudes and in-deep, cold waters.     

Feasibility of composting combinations of sewage sludge,olive mill waste and winery waste in a rotary drum reactor

Representative samples of the following biowastes typically generated in Castilla La Mancha (Spain) were composted using a pilot-scale closed rotary drum composting reactor provided with adequate control systems: waste from the olive oil industry (olive mill waste; OMW), winery–distillery waste containing basically grape stalk and exhausted grape marc (WDW), and domestic sewage sludge. Composting these biowastes was only successful when using a bulking agent or if sufficient porosity was supported. OMW waste composting was not possible, probably because of its negligible porosity, which likely caused anaerobic conditions. WDW was successfully composted using a mixture of solid wastes generated from the same winery. SS was also successfully composted, although its higher heavy metal content was a limitation. Co-composting was an adequate strategy because the improved mixture characteristics helped to maintain optimal operating conditions. By co-composting, the duration of the thermophilic period increased, the final maturity level improved and OMW was successfully composted. Using the proposed reactor, composting could be accelerated compared to classical outdoor techniques, enabling easy control of the process. Moisture could be easily controlled by wet air feeding and leachate recirculation. Inline outlet gas analysis helped to control aerobic conditions without excessive aeration. The temperature reached high values in a few days, and sufficient thermal requirements for pathogen removal were met. The correct combination of biowastes along with appropriate reactor design would allow composting as a management option for such abundant biowastes in this part of Spain.     

Environmental fate of glyphosate and aminomethylphosphonic acid in surface waters and soil of agricultural basins

Argentinian agricultural production is fundamentally based on a technological package that combines no-till and glyphosate in the cultivation of transgenic crops. Transgenic crops (soybean, maize and cotton) occupy 23 million hectares. This means that glyphosate is the most employed herbicide in the country, where 180–200 million liters are applied every year.     

Environmental Indicators of Biofuel Sustainability: What About Context?

Indicators of the environmental sustainability of biofuel production, distribution, and use should be selected, measured, and interpreted with respect to the context in which they are used. The context of a sustainability assessment includes the purpose, the particular biofuel production and distribution system, policy conditions, stakeholder values, location, temporal influences, spatial scale, baselines, and reference scenarios. We recommend that biofuel sustainability questions be formulated with respect to the context, that appropriate indicators of environmental sustainability be developed or selected from more generic suites, and that decision makers consider context in ascribing meaning to indicators. In addition, considerations such as technical objectives, varying values and perspectives of stakeholder groups, indicator cost, and availability and reliability of data need to be understood and considered. Sustainability indicators for biofuels are most useful if adequate historical data are available, information can be collected at appropriate spatial and temporal scales, organizations are committed to use indicator information in the decision-making process, and indicators can effectively guide behavior toward more sustainable practices.     

Reducing the negative impact of ceftriaxone and doxycycline in aqueous solutions using ferrihydrite/plant-based composites: mechanism pathway

Environmental Science and Pollution Research - The adsorption of ceftriaxone (CET) and doxycycline (DOX) from aqueous solution using ferrihydrite/plant-based composites (silica rice husk) to reduce...     

Estimating net benefits of recreation under conditions of excess demand

The public provision of outdoor recreation necessitates the development of nonmarket measures of the value of resources in recreational use. Such values can be used as surrogates for market values in the decision-making process. Another aspect of recreation as a publicly provided good is the absence of a mechanism to eliminate automatically excess demand. The absence of such a mechanism has resulted in conditions of excess demand at many recreation sites.This paper deduces the implications of excess demand for the travel cost method of benefit estimation. We show that when excess demand results in rationing at a particular site, the travel cost method will underestimate the true benefits of the site. The results are important because they help identify the direction of bias of one measure of the benefits from the use of a natural resource.     

Household, hotel and market waste audits for composting in Vietnam and Laos.

In Da Nang and Ha Long, Vietnam and in Vientiane, Laos, there was interest by local authorities in separating and composting waste in order to reduce environmental and health problems at the local landfills and to produce a soil conditioner for local agricultural use. To assist in the planning of composting projects, three studies were carried out to estimate waste quantities and composition. 1. A 9-day audit of waste from 45 vendors in a market in Vientiane, the capital of Laos. The total quantity of waste and the quantity in each of nine categories were estimated for each of six different types of vendors. 2. A 7-day audit of waste disposed by three hotels in the tourist area of Ha Long, Vietnam. Waste quantities were estimated in total, on a per guest basis, and in three main categories: compostables, recyclables and miscellaneous. 3. A 7-day audit of waste collected from 74 households in Da Nang, the fourth largest city in Vietnam. Waste from each household was separated into compostable and non-compostable waste. Over 60% of each waste source comprised compostable waste and this was considered significant enough to warrant further planning of composting operations.