Disposal of heavy metal bearing hazardous waste using chemical fixation and solidification

The Chemical Fixation and Solidification (CFS) process has been successfully applied to flyash from a glass-manufacturer and to arsenic trioxide wastes from roasting auriferous pyrite concentrates. Both wastetypes have been solidified with or without chemical fixation by addition of various amounts of Portland Cement. Leachability and unconfined compressive strength of the produced solidified waste were used as parameters to assess the efficacy of the CFS process. Leachability data for the solidified wastes was obtained by conducting standard leaching tests such as the Toxicity Characteristic Leaching Procedure (TCLP) and the Dynamic Leach Test (DLT). For the arsenic trioxide waste the leachability data was used to model long term leachability. This paper outlines the results from the application of the CFS process to industrial flyash and of arsenic trioxide waste and discuss the long term leaching models developed to predict leaching from arsenic trioxide waste

Sustainability, certification, and regulation of biochar

Biochar has a relatively long half-life in soil and can fundamentally alter soil properties, processes, and ecosystem services. The prospect of global-scale biochar application to soils highlights the importance of a sophisticated and rigorous certification procedure. The objective of this work was to discuss the concept of integrating biochar properties with environmental and socioeconomic factors, in a sustainable biochar certification procedure that optimizes complementarity and compatibility between these factors over relevant time periods. Biochar effects and behavior should also be modelled at temporal scales similar to its expected functional lifetime in soils. Finally, when existing soil data are insufficient, soil sampling and analysis procedures need to be described as part of a biochar certification procedure.O “biochar” tem um tempo de meia-vida no solo relativamente longo e pode alterar substancialmente as propriedades, processos e funções do solo. A perspectiva da aplicação de “biochar” aos solos, em escala global, evidencia a importância de se lhe atribuir um processo de certificação sofisticado e rigoroso. O objetivo deste trabalho foi discutir o conceito da integração das propriedades do “biochar” com os fatores ambientais e socioeconômicos relevantes do local de aplicação selecionado, como parte de um procedimento de certificação sustentável que otimize a complementaridade e a compatibilidade entre esses fatores, em períodos de tempo relevantes. Os efeitos e o comportamento do “biochar” devem, também, ser modelados em escalas temporais similares às de seu tempo de vida funcional nos solos do local selecionado. Finalmente, onde os dados existentes sobre as características do solo forem insuficientes, procedimentos de amostragem e análise do solo devem ser descritos como parte do procedimento de certificação do “biochar”.publishe

Is sustainability certification for biochar the answer to environmental risks?

Biochar has the potential to make a major contribution to the mitigation of climate change, and enhancement of plant production. However, in order for biochar to fulfill this promise, the industry and regulating bodies must take steps to manage potential environmental threats and address negative perceptions. The potential threats to the sustainability of biochar systems, at each stage of the biochar life cycle, were reviewed. We propose that a sustainability framework for biochar could be adapted from existing frameworks developed for bioenergy. Sustainable land use policies, combined with effective regulation of biochar production facilities and incentives for efficient utilization of energy, and improved knowledge of biochar impacts on ecosystem health and productivity could provide a strong framework for the development of a robust sustainable biochar industry. Sustainability certification could be introduced to provide confidence to consumers that sustainable practices have been employed along the production chain, particularly where biochar is traded internationally

The Quest for the Cosmological Parameters

Abstract. The following review is based on lectures given in the 1 st Samos Cosmology summer school. It presents an attempt to discuss various issues of current interest in Observational Cosmology, the selection of which as well as the emphasis given, reflects my own preference and biases. After presenting some Cosmological basics, for which I was aided by excellent text-books, I emphasize on attempts to determine some of the important cosmological parameters; the Hubble constant, the curvature and total mass content of the Universe. The outcome of these very recent studies is that the concordance model, that fits the majority of observations, is that with Ωm + ΩΛ = 1, ΩΛ ≃ 0.7, H ◦ ≃ 70 km s −1 Mpc −1, ΩB ≃ 0.04 and spectral index of primordial fluctuations, the inflationary value n ≃ 1. I apologise before hand for the many important works that I have omitted and for the possible misunderstanding of those presented. 1 Background- Prerequisites The main task of Observational Cosmology is to identify which of the idealized models, that theoretical Cosmologists construct, relates to the Universe we liv