Phosphate removal in agro-industry: pilot- and full-scale operational considerations of struvite crystallization

Pilot-scale struvite crystallisation tests using anaerobic effluent from potato processing industries were performed at three different plants. Two plants (P1 & P2) showed high phosphate removal efficiencies, 89 + 3% and 75 + 8%, resulting in final effluent levels of 12 + 3 mg PO4/3- -P/L and 11 + 3 mg PO4/3- -P/L, respectively. In contrast, poor phosphate removal (19 + 8%) was obtained at the third location (P3). A noticeable difference in the influent Ca2+/PO4/3- -P molar ratio was observed between the test sites, ranging from 0.27 + 0.08 (P1), 0.62 + 0.18 (P2) and 0.41 + 0.04 (P3). A negative effect on struvite formation occurred when a Ca2+/PO4/3- -P molar ratio of 1.25 + 0.11 was obtained after initial pH increase in the stripper at P3. A full-scale struvite plant treating 90–110 m3/h of anaerobic effluent from a diary industry also showed Ca2+ interference. Initially in this plant, influent phosphate levels ranging from 40 to 45 mg PO4/3- -P/L were decreased to below 10 mg PO4/3- -P/L, but no struvite was produced. A shift in Ca2+/PO4/3- -P molar ratio from 2.69 to 1.36 by an increased phosphate concentration resulted in average total phosphorus removal of 78 + 7%, corresponding with effluent levels of 14 + 4 mg Ptotal/L(9 + 3 mg PO4/3- -P/L). Under these conditions pure spherical struvite pellets of 2–6 mm were produced

La teoría de juegos en su laberinto

International audienceThis work aims at exposing from a critical and original perspective the theoretical difficulties implied in the use of game theory in economics, so the reason of the problems being discussed today by the academic community regarding this mathematical tool may be understood. We will try to show that game theory is not neutral in at least two ways. After showing this, our purpose will be to unveil the connection it has, when applied to the field of industrial organization, with marginalist value theory. In this way, the limitations of game theory when it comes to understand the phenomenons related to the value will be exposed.El presente trabajo busca exponer desde una perspectiva crítica y original las dificultades teóricas que supone el uso de la teoría de juegos en economía, para así poder entender el porqué de los problemas que se discuten hoy en la academia en torno a esta herramienta matemática. Intentaremos mostrar que la teoría de juegos no es neutral en al menos dos sentidos. Una vez mostrado esto, se buscará develar qué conexión hay entre ésta aplicada al campo de la organización industrial y la teoría del valor marginalista. Se expondrán así los límites de la teoría de juegos para comprender los fenómenos relacionados al valor

Data as a common in the sharing economy: a general policy proposal

It is nowadays a common place to say that the sharing economy is not really about sharing but about making profits and benefiting a few much more than others. A movement that takes the best of the technologies of sharing economy platforms but orients it to benefiting all, platform cooperativism, is on the rise. Nonetheless, it is far from being popular and nothing indicates that it will. This paper investigates the reasons why dominant platforms remain dominant and proposes a policy that aims at curtailing their dominance, fostering platform cooperativism and maximizing the beneficial societal effects that can be derived from exploiting the data generated in platforms. The paper is structured as follows. Section 1 reviews current definitions of the sharing economy, points out their contributions and limitations and offers a novel and more accurate definition. Section 2 briefly introduces platform cooperativism to show why it can be a tool to fix many of the problems of the sharing economy. Section 3 explains and discusses market power mechanisms specific to the sharing economy that help dominant platforms to remain dominant. Some already existing and proposed solutions to counter these market power mechanisms such as reputation passports, a market for personal data and antitrust remedies are evaluated. Section 4 presents a general policy proposal based on making data a common in the sharing economy using reciprocity licenses. Section 5 offers some clarifications regarding the proposal and sketches some of its shortcomings and open questions that arise from it

El Castillo Iron Age Cemetery (Castejón, Navarra). Metal Vessels and Tools Used in Sacrifices and Funerary Feasts the Middle Ebro Valley (VI – III BC)

El presente estudio tiene por objeto estudiar y analizar la vajilla y el instrumental metálico relacionados con los rituales de sacrificio y banquete funerario que se practicaron en el valle medio del Ebro durante los siglos centrales del Ier Milenio a. C. La investigación se ha centrado en la extensa información que proporciona la necrópolis de El Castillo (Castejón, Navarra), un espacio funerario que, por el momento, constituye una asombrosa excepción en un horizonte marcado por la ausencia o la parquedad de los datos.The present paper studies and analiyzes the metal vessels and tools related to the rituals of sacrifice and funerary feasts in the middle Ebro valley during the middle centuries of the 1st Millennium BC. The investigation focuses on the extensive information provided by the necropolis of El Castillo (Castejón, Navarra), a burial area that, for the time being, is an amazing exception in a horizon marked by the lack or shortage of information

Prospección arqueológica aplicada a la localización de despoblados medievales en el área suroriental en la cuenca de Pamplona

Este artículo pretende establecer una sincronía entre el trabajo arqueológico de campo y el registro documental, además de dar a conocer una serie de pautas, que necesariamente hay tener en cuenta a la hora de realizar una prospección dirigida a la localización de despoblados medievales. Todo ello enmarcado en un ámbito geográfico concreto, en este caso el área suroriental de la Cuenca de Pamplona

Technical and economic feasibility of gradual concentric chambers reactor for sewage treatment in developing countries

A major challenge in developing countries concerning domestic wastewaters is to decrease their treatment costs. In the present study, a new cost-effective reactor called gradual concentric chambers (GCC) was designed and evaluated at lab-scale. The effluent quality of the GCC reactor was compared with that of an upflow anaerobic sludge bed (UASB) reactor. Both reactors showed organic matter removal efficiencies of 90%; however, the elimination of nitrogen was higher in the GCC reactor. The amount of biogas recovered in the GCC and the UASB systems was 50% and 75% of the theoretical amount expected, respectively, and both reactors showed a slightly higher methane production when the feed was supplemented with an additive based on vitamins and minerals. Overall, the economical analysis, the simplicity of design and the performance results revealed that the GCC technology can be of particular interest for sewage treatment in developing countries

A Coat of Many Colours - New Concepts and Metrics of Economic Power in Competition Law and Economics

The digital economy has brought new business models that rely on zero-price markets and multi-sided platforms nested in business ecosystems. The traditional concept of market power used by competition authorities cannot engage with this new reality in which (economic) power manifests beyond price and output within a relevant market. These developments have culminated in multiple recent calls for a more multidimensional concept of power. Consequently, suggestions over new concepts of power triggering antitrust/regulatory intervention, such as ‘strategic market status’, ‘conglomerate market power’, ‘intermediation power’, ‘structuring digital platforms’, or ‘gatekeepers’ have proliferated to complete, or even substitute, the archetypical concept of market or monopoly power in competition law. However, a theoretical framework for this multidimensional concept of power that can set the basis for new metrics is missing. This article makes three contributions in that direction. First, we conceptualize different forms of (economic) power that go beyond competition within a single relevant market in terms of competition law and economics. Second, we propose new metrics to measure two forms of power: panopticon power and power based on differential dependency between value co-creators. Third, we test the latter and show how they could reduce false positives and false negatives when assessing dominance

Small aggregates can cause nitrite accumulation in one-stage partial nitritation and anammox

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Uneven development patterns in global value chains: An empirical inquiry based on a conceptualization of GVCs as a specific form of the division of labor

This paper has three interconnected aims: proposing a novel and rigorous definition of a global value chain (GVC) that more easily permits the delineation of its frontiers; creating new indicators of GVC participation and value capture that can overcome the limitations of the existing ones; and offering empirical evidence demonstrating that participation in global value chains is part of an uneven development process that produces a variety of distinct integration patterns that differ with respect to economic and social outcomes.The paper is structured as follows. Section 1 offers a definition of GVCs that conceives the latter as a specific form of the division of labor and therefore facilitates the delineation of the frontiers of a GVC. Building on this definition, Section 2 proposes new indicators to measure GVC participation and value capture. Section 3 provides empirical evidence to argue that, contrary to what mainstream economics and international organizations state, larger participation in GVCs does not necessarily lead to higher levels of value capture. Section 4 offers some theoretical justifications to interpret these findings and adds other measures such as the level of productive investment and dimensions of social outcomes in order to better understand differentiated development patterns in GVCs. Sections 5, 6 and 7 empirically show the heterogeneity of development patterns in GVCs for 51 countries between 1995 and 2008. Using country-level data on GVC participation, value capture, investment rates and social indicators (Gini coefficient, labor’s share of income, median income and employment rate), we perform a principal component analysis and a cluster analysis. We find three distinct development patterns in GVCs: reproduction of the core, immiserizing growth, and a social upgrading mirage. We conclude by underlying the apparent complementarity between these development patterns and by identifying some limitations of the paper that open the way to further research.Cet article a trois objectif interconnectés : proposer une définition originale et rigoureuse d’une chaîne globale de valeur (CGV) qui permette de délimiter ses frontières plus facilement ; créer de nouveaux indicateurs de participation aux CGV et de capture de valeur qui puissent surmonter les limites de ceux qui existent actuellement ; et offrir des preuves empiriques qui montrent que la participation aux chaînes globales de valeur est un processus qui produit une variété de formes d’intégration qui différent en termes de résultats économiques et sociaux.L’article est organisé comme suit. La Section I offre une définition des CGV qui les conçoit comme une forme spécifique de la division du travail et facilite ainsi la démarcation des frontières d’une CGV. En s’appuyant sur cette définition, la Section II propose de nouveaux indicateurs pour mesurer la participation aux CGV et la capture de valeur. La Section 3 apporte des preuves empiriques pour argumenter que, contrairement à ce que l’économie orthodoxe et les organisations internationales soutiennent, une plus grande participation aux CGV ne conduit pas nécessairement à des niveaux de capture de valeur plus élevés. La Section 4 offre quelques justifications théoriques pour interpréter ces résultats et ajoute d’autres mesures telles que le niveau d’investissement productif et des indicateurs sociaux dans l’objectif de mieux comprendre les modèles de développement différentiés dans les CGV. Les Sections 5, 6 et 7 montrent empiriquement l’hétérogénéité des modèles de développement dans les CGV pour 51 pays entre 1995 et 2008. En utilisant des données de niveau national sur la participation aux CGV, la capture de valeur, le taux d’investissement et des indicateurs sociaux (coefficient de Gini, part des salaires dans le revenu, revenu médian et taux d’activité) nous réalisons une analyse en composantes principales et une analyse de cluster. Nous trouvons trois modèles de développement différentiés dans les CGV : reproduction du noyau, croissance appauvrissante et mirage de progrès social. Nous concluons en soulignant l’apparente complémentarité entre ces modèles de développement et en identifiant quelques limites de l’article qui ouvrent la voie à de la recherche future