Remediation Technologies - A Comparative Study

Contaminated land is a legacy of industrial revolution as a result of rapid growth of industries. Since long back, the disposal of liquid and solid wastes on land though undesirable, has been in practice. The leachate generated out from these hazardous wastes infiltrates into the ground and causes multiple problems viz., ground water pollution, soil pollution, loss of nutrition value of soil and thereby severe damage to plantation growth, changes in the soil behavior (excessive swell/shrink) depending on the nature of waste. It also causes serious distress to the existing structures such as pavements, foundations, underground pipelines and culverts. The changes in the soil behaviour caused by ground contamination can lead to structural failures. The present paper describes various physical, chemical, biological, thermal and solidification/stabilization methods of soil and ground water remediation and their comparison on the basis of applicability, time and cost.

SUSTENTABILIDADE COM FOCO NA LOGÍSTICA REVERSA DA INDÚSTRIA DE TINTAS E VERNIZES

A indústria química, considerando os impactos ambientais decorrentes das suas atividades, está sendo cobrada e monitorada pela sociedade e pelo governo. A legalidade em torno destas empresas no quesito ambiental vem sendo acompanhada com preocupação. No ano de 2010, foi aprovada a Politica Nacional de Resíduos Sólidos. Trata-se de uma Lei que institui uma relação de responsabilidade compartilhada entre o poder público, fabricantes, comerciantes e consumidor final no que se refere ao gerenciamento do ciclo de vida dos produtos e a sua destinação final, ou seja, a sua Logística Reversa. Deste modo, o presente estudo tem como objetivo analisar o comportamento das indústrias de tintas da região Sul do Brasil em relação às práticas de Logística Reversa. Para tanto, foi realizada uma pesquisa de natureza quantitativa a partir de questionário online enviado a um representante de 29 indústrias químicas localizadas na região do Sul do Brasil. Obteve-se um retorno de 25 questionários e os principais resultados demonstram que a aplicação da logística reversa, tanto com foco na preocupação com os impactos ambientais causados, quanto com o atendimento à Política Nacional de Resíduos Sólidos, ainda não está presente na totalidade das empresas pesquisadas. Além dos custos envolvidos neste processo, fatores como a falta de conhecimento por parte dos clientes sobre a possibilidade de retorno da embalagem, e a falta de consciência ambiental, como a chance de contaminação dos solos, por exemplo, também foram relatados pelos respondentes. Palavras-chave: Sustentabilidade. Logística reversa. Política Nacional de resíduos sólidos.ABSTRACTThe chemical industries, considering environmental impacts from its activities, has being charged and monitored by the society and government. Legal aspects regarding those companies on environmental questions came with some concern. On 2010 was approved by the Congress, the National Politics on Solids Waste. This regulation consists on relate the shared responsibility between public authorities, manufacturers, traders and final consumers on management of on products life cycle and their final destination, that means Reverse Logistic. To have a better understanding, a quantitative research was made by sending an online survey to representative of 29 chemical industries located in South of Brazil. The sample was composed by 25 industries and the main results shows that applying the Reverse Logistic, both focus on environmental impact concern and being compliance with National Politics Solids Waste, are still a restrict number of companies to following completely the law. Besides the costs involved on these processes, elements like lack of knowledge from part of customers on the possibility to return de package and lack of environmental conscience, like the possibility of ground contamination for example, also were related by the surveyed companies.Keywords: Sustainability. Reverse logistic. National politics on solids Waste.

The Phytoremediation of Radioactively Contaminated Land: A Feasible Approach or Just Bananas?

Soil is an essential component of all terrestrial ecosystems and is under increasing threat from human activity. Techniques available for removing radioactive contamination from soil and aquatic substrates are limited and often costly to implement; particularly over large areas. Frequently, bulk soil removal, with its attendant consequences, is a significant component of the majority of contamination incidents. Alternative techniques capable of removing contamination or exposure pathways without damaging or removing the soil are therefore of significant interest. An increasing number of old nuclear facilities are entering ‘care and maintenance’, with significant ground contamination issues. Phytoremediation — the use of plants’ natural metabolic processes to remediate contaminated sites is one possible solution. Its key mechanisms include phytoextraction and phytostabilisation. These are analogues of existing remedial techniques. Further, phytoremediation can improve soil quality and stability and restore functionality. Information on the application of phytoremediation in the nuclear industry is widely distributed over an extended period of time and sources. It is therefore difficult to quickly and effectively identify which plants would be most suitable for phytoremediation on a site by site basis. In response, a phytoremediation tool has been developed to address this issue. Existing research and case studies were reviewed to understand the mechanisms of phytoremediation, its effectiveness and the benefits and limitations of implementation. The potential for cost recovery from a phytoremediation system is also briefly considered. An overview of this information is provided here. From this data, a set of matrices was developed to guide potential users through the plant selection process. The matrices take the user through a preliminary screening process to determine whether the contamination present at their site is amenable to phytoremediation, and to give a rough indication as to what plants might be suitable. The second two allow the user to target specific plant species that would be most likely to successfully establish based on prevailing site conditions. The outcome of this study is a phytoremediation tool that can facilitate the development of phytoremediation projects, avoiding the need for in-depth research to identify optimal plant species on a case-by-case basis.

Reactive Transport Modelling of the Interaction of Fission Product Ground Contamination With Alkaline and Cementitious Leachates

The fission products Cs-137 and Sr-90 are amongst the most common radionuclides occurring in ground contamination at the UK civil nuclear sites. Such contamination is often associated with alkaline liquids and the mobility of these fission products may be affected by these chemical conditions. Similar geochemical effects may also result from cementitious leachate associated with building foundations and the use of grouts to remediate ground contamination. The behaviour of fission products in these scenarios is a complex interaction of hydrogeological and geochemical processes. A suite of modelling tools have been developed to investigate the behaviour of a radioactive plume containing Cs and Sr. Firstly the effects of sorption due to cementitious groundwater is modelled using PHREEQC. This chemical model is then incorporated into PHAST for the 3-D reactive solute transport modeling. Results are presented for a generic scenario including features and processes that are likely to be relevant to a number of civil UK nuclear sites. Initial results show that modelling can be a very cost-effective means to study the complex hydrogeological and geochemical processes involved. Modelling can help predict the mobility of contaminants in a range of site end point scenarios, and in assessing the consequences of decommissioning activities.