Effect of improved electrokinetic remediation treatments on the mobility and removal of metals in sediment

Abstract

<p>U radu je: 1. Određena efikasnost elektrokinetičkih tretmana (konvencionalni tretman, tretman sa izmenom polariteta, tretman sa dve anode i heksagonalni dvodimenzionalni elektrokinetički tretman) koji izuzimaju dodatak agenasa u tretirani sediment, za uklanjanje metala; 2. Ispitan je uticaj diskontinuiteta napajanja strujom (tokom noći), kao i uticaj oscilacija jačine električne energije pri primeni solarnih panela na efikasnost tretmana; 3. Ispitan je uticaj geohemije sedimenta, fizičko-hemijskih promena u sistemu i karakteristika prisutnog zagađenja (oblici pojavljivanja metala, koncentracije) na efikasnost elektrokinetičkog procesa. 4. Izvr&scaron;ena je procena rizika u sistemu sediment/voda pre, tokom i nakon tretmana; 5. Primenjen je matematički model na dobijene rezultate. Na osnovu određene efikasnosti i procene rizika tretmana elektrokinetičke remedijacije na realan problem Velikog Bačkog kanala zaključeno je, da je najbolja opcija dvoanodni tretman u kome se primenjuju solarne panele (e9). Dobijeni rezultati tretmana ukazuju da diskontinuiteti napajanja strujom (tokom noći), kao i uticaj oscilacija jačine električne energije pri primeni solarnih panela nemaju značajnog uticaja na efikasnost procesa. &Scaron;to se tiče, geohemije sedimenta, pokazalo se da ona ima snažan uticaj i da upravo ona određuje fizičko-hemijske promene koje se događaju u sedimentu tokom sprovođenja tretmana elektrokinetičke remedijacije. Ključ uspeha ovih tretmana sedimenta jeste i zadržavanje metala u frakcijama (karbonatna i reducibilna) koje lak&scaron;e migriraju. Primenom matematičkog modela zaključeno je da se mogu predvideti promene koncentracija metala bez sprovođenja eksperimenata, &scaron;to je od krucijalnog značaja za buduća istraživanja.</p>

<p>This work includes: 1. An investigation into efficiency of various electrokinetic treatments (a conventional treatment, and treatments with changing polarity, two anodes and two-dimensional hexagonal electrodes) without the addition of agents to the treated sediment, for the removal of metals; 2. An investigation of the influence of discontinuous (off during the night) and oscillating power supplies on the application of solar panels and their effect on the efficacy of the treatment; 3. A study on the influence of sediment geochemistry, physico-chemical changes in the system and the characteristics of the pollution present (metals speciation and concentration) on the efficiency of the electrokinetic process; 4. A risk assessment of the sediment/water system before, during and after the treatment; 5. Mathematical modelling of the results obtained. Based on the risk assessment and the efficiency of the electrokinetic treatments in the Veliki Backa canal sediment, it was concluded that the best remediation option was a two anode treatment using solar panels (e9). The investigation into the influence of treatments using discontinuous (off during the night) and oscillating power supplies showed they did not have a significant impact on the efficiency of the process. Sediment geochemistry was shown to have a strong influence, determining the physical and chemical changes that occur in the sediment during the implementation of the electrokinetic remediation. The key to success for these treatments is the retention of metals in the fractions (carbonate and reducible) which more easily migrate. It is concluded that the mathematical model can be applied to successfully predict thechanges in the concentration of metals without experimentation, which is of crucial importance for future studies.</p>