BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Permeable reactive barrier for groundwater remediation - Ziyad Abu nada\, CUED DTSTART:20141127T170000Z DTEND:20141127T180000Z UID:TALK54236@talks.cam.ac.uk CONTACT:Anama Lowday DESCRIPTION:A Permeable Reactive Barrier (PRB) is an in situ permeable tre atment zone designed to intercept and remediate a contaminant groundwater plume. PRB was first implemented in the early 1990s and PRBs have become a n important remediation technique among the various technologies available to remediate groundwater contamination. Soil mix technology (SMT) is a re latively recent development PRB installation technique in which reactive m aterials are mixed in-situ with the native soil to intersect the flow of c ontaminated groundwater. SMT has shown to be cost effective and versatile system with many environmental advantages over other remediation technique s. Project SMiRT (Soil Mix Remediation Technology) is a real field remedia tion trial involved the execution of the largest research field trials in the UK for the application of SMT in land remediation. The main aim of the project was field validation\, testing and assessment to increase stakeho lder confidence in and uptake of SMT for land remediation in the UK. PRB t echnology represents one of the remediation trials within SMiRT project wh ere a range of aluminosilicates\, organoclays\, inorgano-organo bentonites and natural zeolite were used in different combinations as reactive mater ials. The treatment process associated with these materials is sorption an d their high sorptive capacity and ability to deal with a range of contami nants make them ideal for use in PRB systems. The objectives are to invest igate the (i) materials relative adsorption efficiency\, (ii) reaction kin etics (iii) mass balance of the contaminants (iv) monitor the groundwater remediation through PRB system in field scale (v) and to evaluate the SMT PRB performance in field scale. Inorgano- organobentonites (IOB) are produ ced by the exchange of organic quaternary ammonium structure for inorganic ions (Na+\, Ca2+) on the internal and external surfaces of bentonite. Pil laring agents with Aluminium are used to intercalate QAC within bentonite layers. IOB have significantly higher sorptive capacity for many organic p ollutants relative to conventional bentonite. Three different IOBs were used in the current study. The material were characterised using X-ray dif fraction (d-spacing changes) and thermo-gravimetric analysis (hydrophilic nature and carbon content). According to batch tests with model contaminan t solutions (T\, E\, X) the maximum adsorption order was IOB2-OCg-Zlt >= O Cg > IOB-OC>> IOB1 >IOB2> IOB3> IOB2-Zlt. The adsorption was modelled by L angmuir and Freundlich isotherms and showed high adsorption capacity. The materials showed higher affinity to the real contaminated site groundwater (average 80mg/g) with greater adsorption capacity than model contaminants (30mg/g) and the adsorption was mainly due partitioning effect. Desorptio n tests were carried out and showed strong contaminants bonding. Materials also showed greater adsorption capacity towards hydrocarbons and (dodecan e) with more than 550 mg/g. Column test using same materials indicated sim ilar results with similar sorptive preference order. The column tests perf ormed complemented the batch tests in examining flow conditions\, groundwa ter and model contaminants to simulate the field conditions. Materials sho wed slight to no effect on aquifer permeability and the mixes have same or der of magnitude. Site cores from within the PRB walls showed high vulnera bility with indications of good mixing quality and consistency down to 5 m depth. Groundwater pumping through the PRB indicated occasional improveme nt in groundwater quality parameters where more pumping still needed. Soli d state sensors were developed to facilitate real time groundwater monitor ing. It was tested in lab scale with the use of model contaminated solutio n. Sensor step curve with MTBE and xylene showed high response up to 100pp m. Results indicated that sensors response time depends on material fabric ations and temperature. The results of this research confirmed the efficie ncy of the used materials in PRB application with the varied efficiency du e to materials properties. It also emphasises the difference in materials performance at lab and field scale. More time and work are needed to draw general conclusions on field trial quality assurance. LOCATION: Cambridge University Engineering Department\, Lecture Room 6 END:VEVENT END:VCALENDAR