Sustainable remediation panel—Measuring the social and economic benefits of a sustainable remediation project

Remediation developed a Sustainable Remediation Panel in the Summer 2009 issue, which featured the Sustainable Remediation Forum White Paper. The panel is composed of leaders in the field of sustainable remediation who have volunteered to provide their opinions on difficult subjects related to the topic of how to integrate sustainability principles into the remediation practice. The panel's opinions are provided in a question‐and‐answer format, whereby selected experts provide an answer to a question. This issue's question is provided below, followed by opinions from five experts in the remediation field.

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A systematic approach to estimating the assessment phase of a remediation project

Environmental assessment consists of scientific studies to define contamination at a potential release site or sites and to evaluate the risk posed to human health and the environment. These studies are performed within a prescribed regulatory framework. There is a high degree of uncertainty associated with preparing cost and schedule estimates for activities such as site characterization, risk assessment, and evaluation of remediation alternatives. This article describes the approach that Sandia National Laboratories is using to meet the challenge of estimating the assessment phase of its Environmental Restoration Project. Emphasis is placed on lessons learned, with examples given to illustrate the approach.     

Interim pump-and-treat remediation of a hydrocarbon-contaminated aquifer

The continuous and discontinuous release of petroleum hydrocarbons from an oil refinery in Alaska resulted in the contamination of an unconfined glacial outwash aquifer. Geologic conditions at the site allowed for the vertical migration of hydrocarbon product to the water table and subsequent formation of an areally extensive floating product layer. Since the petroleum hydrocarbon phase would provide a major source of BTX (benzene, toluene, xylene) contamination to the groundwater, interim product and groundwater recovery measures were initiated to limit aquifer degradation. Phase I remedial activities involved the operation of nine well pairs, with one well used for groundwater extraction and the other for product recovery. Phases II and III involved expansion of the recovery well network and use of a two-pump system. Petroleum product recovered was reprocessed at the refinery. Contaminated groundwater was initially treated using the refinery's wastewater treatment system, but treatment inefficiencies and continued system expansion necessitated use of a separate treatment unit. Performance evaluations indicate that the remedial phases have been successful in halting further contaminant migration and in recovering a significant volume of the released petroleum hydrocarbons.     

Fast-track remediation for redevelopment of a former integrated steel mill site

Remedial action was initiated and completed on an approximately 500-acre brownfield site in southern California within a period of five months during the summer of 1995. Remedial actions included design and construction of an approximately 14-acre cap, including a synthetic membrane; design, construction, and testing of an in-situ soil vapor extraction system; excavation, on-site treatment, and off-site disposal of approximately 7,000 cubic yards of residual waste and affected soil; and verification sampling, analysis, and health risk screening in 20 units of a former integrated steel mill. Completion of remedial action on this portion of the mill site within this time frame was required due to site redevelopment plans which included construction of an auto raceway with scheduled races in early 1997. Rapid remedial action was possible only through simultaneous completion of multiple remediation tasks. This could be done only with continuous communication and close coordination among the site owner, lead regulatory agency, and contractors.     

Chemical augmentation for the remediation of a hydrocarbon‐contaminated site

Field trials with inorganic fertilizer (nitrogen, phosphorus, and potassium) nutrients were simulated in the greenhouse to remediate hydrocarbon‐polluted soils from a spill site in the Niger Delta, Nigeria. Samples of the polluted soils taken from two depths were displayed in a randomized complete block (RCB) design and treated with 10–100 g of (NH₄)₂SO₄, KH₂PO₄, and KCl. The agronomic addition of the chemical nutrients was found to enhance the concentrations of nitrate‐nitrogen, phosphate‐phosphorus, and potassium in the soils. Pretreated nitrate‐nitrogen content ranged from 432 to 590 mg/kg in the polluted samples (with a control at 522 mg/kg), while posttreatment concentrations were 3,285 ± 154 mg/kg and 3,254 ± 159 mg/kg for surface and subsurface soils, respectively. © 2007 Wiley Periodicals, Inc.     

Landfill mining and waste characterization: a strategy for remediation of contaminated areas

This article describes landfill-mining tests, including excavation, screening, and fraction characterization, carried out in the Msalycke and Gladsax landfills for municipal solid waste (MSW) in Sweden. The excavated waste in these two sites was 17–22 and 23–25 years old, respectively. The main part of Msalycke was unaffected by degradation, and during excavations no substantial amount of biogas was detected. After screening, three size fractions were obtained: <18mm, 18–50mm, and >50mm. Soil amendment and anaerobic digestion with energy extraction are suggested for the first and second fraction, respectively. Incineration with energy recovery is possible with the third fraction after any coarse (inert) material is removed, and construction/demolition waste can easily be recycled provided that it is not contaminated by hazardous material. Excavated waste taken from different depths was also analysed and compared in relation to composition, calorific value, and leachate constituents.     

Case study: On-site remediation of soil and groundwater for a michigan town's water supply

In 1993 environmental consultants, working in concert with the State of Michigan, discovered groundwater contamination that threatened the drinking water supply of the town of Big Rapids. The contamination originated from leaking underground storage tanks and gasoline lines, which were removed. A pilot study indicated the contaminated area extended to 240′ x 180′ and affected soil as well as groundwater. A remediation plan was designed by and implemented by Continental Remediation Systems, Inc., a Natick, Massachusetts, firm. The remediation plan is ongoing and includes an interceptor trench to stop gasoline from flowing into the creek, as well as air sparging to vent and treat the contaminated soil. It is anticipated that the remediation project will take six months to complete. The chief advantage of on-site remediation is that it avoids the costs and liabilities associated with landfill disposal and no materials need leave the site.     

Continuous water‐level monitoring in the assessment of groundwater remediation and refinement of a conceptual site model

An Erratum has been published for this article in Remediation 16(1) 2005, 155–157. Water‐level data collection is a fundamental component of groundwater investigations and remediation. While the locations and depths of monitored wells are important, the frequency of data collection may have a large impact on conclusions made about site hydrogeology. Data‐logging water‐level probes may be programmed to record water levels at frequent intervals, providing site decision makers with abundant, detailed information on the response of an aquifer to both anticipated and unforeseen stresses. In this study, a network of movable probes has provided several years of hourly water‐ level data. The understanding of the site's phytoremediation system has been enhanced by the continuous data, but subsequent insights into an unexpected situation regarding the site's infrastructure have been the most valuable result of the monitoring program. © 2005 Wiley Periodicals, Inc.     

Landfill aeration in the framework of a reclamation project in Northern Italy

In situ aeration by means of the Airflow technology was proposed for landfill conditioning before landfill mining in the framework of a reclamation project in Northern Italy. A 1-year aeration project was carried out on part of the landfill with the objective of evaluating the effectiveness of the Airflow technology for landfill aerobization, the evolution of waste biological stability during aeration and the effects on leachate and biogas quality and emissions.The main outcomes of the 1-year aeration project are presented in the paper.The beneficial effect of the aeration on waste biological stability was clear (63% reduction of the respiration index); however, the effectiveness of aeration on the lower part of the landfill is questionable, due to the limited potential for air migration into the leachate saturated layers.During the 1-year in situ aeration project approx. 275 MgC were discharged from the landfill body with the extracted gas, corresponding to 4.6 gC/kgDM. However, due to the presence of anaerobic niches in the aerated landfill, approx. 46% of this amount was extracted as CH₄, which is higher than reported in other aeration projects. The O₂ conversion quota was lower than reported in other similar projects, mainly due to the higher air flow rates applied.The results obtained enabled valuable recommendations to be made for the subsequent application of the Airflow technology to the whole landfill.     

某市河道底泥污染工程总体设计方案

为截流和处理某市内河的外来污染源,河道综合整治工程是某市内河水系底泥污染系统综合开发工程的重要工程之一,主要内容包括:河道工程、截污工程、底泥疏浚、景观工程等.截污工程采取沿河截污,超量溢流的工程方案沿河敷设截污管道,并在河道交汇处设置合流污水调蓄池.     

Use of the Contingent Valuation Method in the assessment of a landfill mining project

A comprehensive approach for the evaluation of the economic feasibility of landfill mining (LFM) should take into account not only the direct costs and revenues for the private investor, but also the social benefits or costs (generally called externalities), in such a way that projects generating major social benefits (and no significant private revenues) are not overlooked.With a view to contributing to the development of a common framework for the evaluation of LFM projects, this paper presents the results of a case study where the issue of the assessment of social benefits from a LFM project is addressed. In particular, the Contingent Valuation Method is applied for the monetary assessment of the community-perceived benefits from the remediation of an old uncontrolled waste deposit by means of LFM and the conversion of the area into a park.Based on the results of a survey carried out on a random sample of people living near the old landfill, the economic values of the individual willingness to pay (WTP) for LFM and the subsequent creation of a public park were calculated and the correlations with the relevant variables (distance from the landfill site, age, income, sex, education level) assessed. The results were then suitably extended and the monetary value of the welfare increase of the whole population resident in the area and potentially affected both by LFM and the creation of the park was calculated.     

燃气-蒸汽联合循环供热项目主机选型方案刍议

发展燃气-蒸汽联合循环供热对于解决经济发展和环境保护具有重要作用,在我国经济发达地区已经开始大规模推广。阐述了燃气一蒸汽联合循环发电、供热技术、特点等,对主机选型方案提出建议。     

Case study of ex situ remediation and conversion to a combined in situ/ex situ bioremediation approach at an oxygenated gasoline release site

In response to an oxygenated gasoline release at a gas station site in New Hampshire, a temporary treatment system consisting of a single bedrock extraction well, a product recovery pump, an air stripper, and carbon polishing units was installed. However, this system was ineffective at removing tertiary butyl alcohol from groundwater. The subsequent remedial system design featured multiple bedrock extraction wells and an ex situ treatment system that included an air stripper, a fluidized bed bioreactor, and carbon polishing units. Treated effluent was initially discharged to surface water. Periodic evaluation of the remediation system performance led to system modifications, which included installing an additional extraction well to draw contaminated groundwater away from an on‐site water supply well, adding an iron and manganese pretreatment system, and discharge of treated effluent to an on‐site drywell. Later, the air stripper and carbon units were eliminated, and an infiltration gallery was installed to receive treated, oxygenated effluent in order to promote flushing of the smear zone and in situ bioremediation in the source area. This article discusses the design, operation, performance, and modifications to the remediation system over time, and provides recommendations for similar sites. © 2007 Wiley Periodicals, Inc.     

Use of Fenton's Reagent as a Disinfectant

Several compositions of Fenton's Reagent and hydrogen peroxide alone were used to disinfect combined sewage samples from a wastewater treatment facility. The presettled samples contained suspended solids (SS) and dissolved organic carbon (DOC) at concentrations of 28 and 290 mg/L, respectively. Disinfection with Fenton's Reagent was carried out at a pH between 5.90 and 6.0 and at a temperature of 25°C. All disinfected samples contained residual oxidants. Under all reaction conditions studied, complete inactivation of E. coli was achieved within one minute of the addition of Fenton's Reagent. Disinfection with hydrogen peroxide alone under similar conditions is incomplete even under much longer contact times. © 2009 Wiley Periodicals, Inc.     

上海某电厂320MW 机组“电改袋”工程

针对上海某电厂4×320 MW机组中的3、4号炉电除尘器提标改造为袋式除尘器项目,介绍了改造背景、改造技术以及改造后袋式除尘器的运行情况。除尘器投运至今,运行稳定,各项指标达到设计要求。