Treatment of petroleum hydrocarbon contaminated soil by combination of electro-Fenton and biosurfactant-assisted bioslurry process.

Removing petroleum hydrocarbons (PHCs) from polluted soil is challenging due to their low bioavailability and degradability. In this study, an experiment was carried out to treat soil polluted with petroleum hydrocarbon using a hybrid electro-Fenton (with BDD anode electrode) and biological processes stimulated with long-chain rhamnolipids (biosurfactants). Electro-Fenton treatment was applied as a pretreatment before the biological process to enhance PHC biodegradability, which would benefit the subsequent biological process. The effects of initial pH, hydroxide concentration, soil organic matter composition, PHCs intermediates during the electro-Fenton process, and total numbers of bacteria in the biological process were analyzed to determine the optimum conditions. The results showed that the optimized electrolysis time for the electro-Fenton was 12 h. The change induced during pretreatment at a specified time was found suitable for the biological process stage and led to 93.6% PHC degradation in combination with the electro-Fenton-and-biological process after 72 h. The combined system's performance was almost 40% higher than individual electro-Fenton and biological treatments. GC-MS analysis confirms the formation of 9-octadecen-1-ol (Z), 2-heptadecene, 1-nonadecene, 1-heneicosene, and pentacosane as fragmentation during the PHCs degradation process. Thus, the electro-Fenton process as pretreatment combined with a biological process stimulated with rhamnolipids (biosurfactants) could be effectively applied to remediate soil polluted with PHCs. However, the system needs further research and investigation to optimize electrolysis time and biosurfactant dose to advance this approach in the soil remediation process.

Insights into rhamnolipid amendment towards enhancing microbial electrochemical treatment of petroleum hydrocarbon contaminated soil.

Environmental pollution by hydrophobic hydrocarbons is increasing, notably nowadays due to a large amount of industrial activity. Microbial electrochemical technologies (MET) are promising bio-based systems which can oxidize hydrophobic hydrocarbon pollutants and produce bioelectricity simultaneously. However, MET faces some issues in terms of soil remediation, including low mass transfer, limited electro-activity of anodes as electron acceptors, low bioavailability of hydrocarbons, and the limited activity of beneficial bacteria and inefficient electron transport. This study aims to investigate the role of the addition of rhamnolipid as an analyte solution to the MET to enhance the efficacy and concurrently solve the abovementioned issues. In this regard, a novel long chain of RL was produced by using low-cost carbon winery waste through non-pathogenic Burkholderia thailandensis E264 strains. Different doses of RL were tested, including 10, 50, and 100 mg/L. A maximum enhancement in the oxidation of hydrophobic hydrocarbons was found to be up to 72.5%, while the current density reached 9.5 Am-2 for the MET reactor having a dose of 100 mg/L. The biosurfactants induced a unique microbial enrichment associated with Geobacter, Desulfovibrio, Klebsiella, and Comamona on the anode surface, as well as Pseudomonas, Acinetobacter, and Franconibacter in soil MET, indicating the occurrence of a metabolic pathway in microbes working with the anode and soil bioelectrochemical remediation system. According to cyclic voltammetry analysis, redox peaks appeared, showing a minor shift in redox MET-biosurfactant compared to the bare MET system. Furthermore, the phytotoxicity of polluted soil to L. sativum seeds after and before MET remediation shows a decrease in phytotoxicity of 77.5% and 5% for MET-biosurfactant system and MET only, respectively. With MET as a tool, this study confirmed for the first time that novel long-chain RL produced from non-Pseudomonas bacteria could remarkably facilitate the degradation of petroleum hydrocarbon via extracellular electron transfer, which provides novel insights to understand the mechanisms of RL regulating petroleum hydrocarbon degradation.

Remediation of soil polluted with petroleum hydrocarbons and its reuse for agriculture: Recent progress, challenges, and perspectives.

Petroleum hydrocarbons (PHs) are used as raw materials in many industries and primary energy sources. However, excessive PHs act as soil pollutants, posing serious threats to living organisms. Various ex-situ or in-situ chemical and biological methods are applied to restore polluted soil. However, most of the chemical treatment methods are expensive, environmentally unfriendly, and sometimes inefficient. That attracts scientists and researchers to develop and select new strategists to remediate polluted soil through risk-based analysis and eco-friendly manner. This review discusses the sources of PHs, properties, distribution, transport, and fate in the environment, internal and external factors affecting the soil remediation and restoration process, and its effective re-utilization for agriculture. Bioremediation is an eco-friendly method for degrading PHs, specifically by using microorganisms. Next-generation sequencing (NGS) technologies are being used to monitor contaminated sites. Currently, these new technologies have caused a paradigm shift by giving new insights into the microbially mediated biodegradation processes by targeting rRNA are discussed concisely. The recent development of risk-based management for soil contamination and its challenges and future perspectives are also discussed. Furthermore, nanotechnology seems very promising for effective soil remediation, but its success depends on its cost-effectiveness. This review paper suggests using bio-electrochemical systems that utilize electro-chemically active microorganisms to remediate and restore polluted soil with PHs that would be eco-friendlier and help tailor-made effective and sustainable remediation technologies.

Utilizing an integrated assessment scheme for sustainable waste management in low and middle-income countries: Case studies from Bosnia-Herzegovina and Mozambique.

Solid waste management assessment methods that simultaneously analyze the economic, social and environmental dimensions are limited. Tools are rarely applied in developing countries because of several constraints encountered during their implementation (e.g. lack of data availability and difficulties concerning data interpretation), consequently hampering the development of sustainable solid waste management practices. In addition, the incorporation of stakeholders in most decision-making tools and processes, as well as the availability of credible data in developing countries is often limited. To address these issues, this paper presents one of the first large scale studies, utilizing a tool, named Integrated Assessment Scheme (IAS). Use of IAS provides a holistic, integrated approach evaluating the economic, environmental and social dimensions in order to support the decision making process and to facilitate more sustainable waste management in low and middle-income countries. The use of IAS in the two case studies from Bosnia-Herzegovina and Mozambique suggests its suitability to communities in similar contexts. However, its limitations are also discussed.

Environmental audits and process flow mapping to assess management of solid waste and wastewater from a healthcare facility: an Italian case study.

In Europe, there are an increasing number of policy and legislative drivers for a more sustainable approach to the management of natural resources as well as for the mitigation of environmental health risks. However, despite significant progress in recent years, there is still some way to go to achieve circularity of process, as well as risk mitigation within organisations. Using a case study of the Gardone Val Trompia hospital in northern Italy, this manuscript offers a novel holistic examination of strategies to enhance resource efficiency and environmental health within a key sector, i.e. the healthcare sector. Through the use of environmental audits and process flow mapping, trends in waste and wastewater arisings and the associated financial and environmental costs and risks were identified. Recommendations for developing more resource efficient approaches as well as mitigating the environmental and public health risks are suggested. These include strategies for improved resource efficiency (including reduction in the hazardous waste) and reduced environmental impacts during the containment, transport and treatment of the waste.

How to assess solid waste management in armed conflicts? A new methodology applied to the Gaza Strip, Palestine.

We have developed a new methodology for assessing solid waste management in a situation of armed conflict. This methodology is composed of six phases with specific activities, and suggested methods and tools. The collection, haulage, and disposal of waste in low- and middle-income countries is so complicated and expensive task for municipalities, owing to several challenges involved, that some waste is left in illegal dumps. Armed conflicts bring further constraints, such as instability, the sudden increase in violence, and difficulty in supplying equipment and spare parts: planning is very difficult and several projects aimed at improving the situation have failed. The methodology was validated in the Gaza Strip, where the geopolitical situation heavily affects natural resources. We collected information in a holistic way, crosschecked, and discussed it with local experts, practitioners, and authorities. We estimated that in 2011 only 1300 tonne day(-1) were transported to the three disposal sites, out of a production exceeding 1700. Recycling was very limited, while the composting capacity was 3.5 tonnes day(-1), but increasing. We carefully assessed system elements and their interaction. We identified the challenges, and developed possible solutions to increase system effectiveness and robustness. The case study demonstrated that our methodology is flexible and adaptable to the context, thus it could be applied in other areas to improve the humanitarian response in similar situations.

Using social network and stakeholder analysis to help evaluate infectious waste management: a step towards a holistic assessment.

Assessing the strengths and weaknesses of a solid waste management scheme requires an accurate analysis and integration of several determining features. In addition to the technical aspects, any such system shows a complex interaction of actors with varying stakes, decision-making power and influence, as well as a favourable or disabling environment. When capitalizing on the knowledge and experience from a specific case, it is also crucial that experts do not "forget" or underestimate the importance of such social determinants and that they are familiar with the methods and tools to assess them. Social network analysis (SNA) and stakeholder analysis (SA) methods can be successfully applied to better understand actors' role and actions, analyse driving forces and existing coordination among stakeholders, as well as identify bottlenecks in communication which affect daily operations or strategic planning for the future way forward. SNA and SA, appropriately adjusted for a certain system, can provide a useful integration to methods by assessing other aspects to ensure a comprehensive picture of the situation. This paper describes how to integrate SNA and SA in order to survey a solid waste management system. This paper presents the results of an analysis of On-Nuch infectious waste incinerator in Bangkok, Thailand. Stakeholders were interviewed and asked to prioritize characteristics and relationships which they consider particularly important for system development and success of the scheme. In such a way, a large quantity of information about organization, communication between stakeholders and their perception about operation, environmental and health impact, and potential alternatives for the system was collected in a systematic way. The survey results suggest that stakeholders are generally satisfied with the system operation, though communication should be improved. Moreover, stakeholders should be strategically more involved in system development planning, according to their characteristics, to prevent negative reactions.