Characterizing the transport and degradation of chlorinated ethenes in fractured aquifers, as well as the assessment of cleanup times, poses an extreme technical challenge. In the presented study, a method to analyze reactive transport and reductive dechlorination of chlorinated solvents in fractured aquifers is developed. A rough-walled parallel-plate model of nonlinear flow behavior is coupled with random-walk particle tracking, incorporating particle exchange between the mobile and stagnant zones, adsorption processes, and reductive dechlorination reaction pathways. The developed methodology, considering reductive dechlorination processes in a Lagrangian framework, is able to simulate the motion of particles affected by first-order network reactions, so that particles move according to their chemical state, affecting physical transport processes (advection, dispersion, mass-transfer exchange between mobile and stagnant zones). The developed model is applied to a case study of groundwater contamination in the industrial area of Bari and Modugno (Italy), where the limestone aquifer has a fractured, karstic nature. The steady-state distribution of the contamination by chlorinated ethenes from a source at a hot spot is obtained and compared with the observed scenario of contamination, in order to estimate the plausible transport and degradation processes and the mass loading at source. The study represents a valuable tool in deciding the role of natural attenuation as a treatment option, where the natural attenuation capacity of groundwater can be integrated with engineering methods in order to obtain site remediation.

La rappresentazione del trasporto e della degradazione degli eteni clorurati negli acquiferi fratturati nonché la valutazione dei tempi di bonifica rappresenta una grande sfida tecnica. Nel presente studio è stato messo a punto una metodologia per analizzare il trasporto reattivo e la declorurazione riduttiva dei solventi clorurati. Un modello a piatti paralleli con superfici ruvide e flusso non lineare è accoppiato con un modello “random-walk particle tracking”, includendo lo scambio di particelle tra le zone mobili e stagnanti, i processi di adsorbimento, e i percorsi di declorurazione riduttiva. La metodologia sviluppata, che considera i processi di declorurazione riduttiva in uno schema Lagrangiano, permette di simulare il moto delle particelle interessate da diverse cinetiche di reazione del primo ordine, cosicché le particelle si muovono secondo il loro stato chimico che si ripercuote sui processi fisici di trasporto (advezione, dispersione, scambio di massa tra le zone mobili e stagnanti). Il modello sviluppato è applicato al caso di studio della contaminazione delle acque sotterranee di Bari e Modugno (Italia), dove l’acquifero carbonatico si presenta fratturato e carsico. Si è ottenuta la distribuzione stazionaria della contaminazione da eteni clorurati da una sorgente in corrispondenza del “hot spot” più ragionevole sulla base del confronto con lo scenario di contaminazione osservato, al fine di stimare i processi di trasporto e degradazione e la portata di immissione dei contaminanti alla sorgente. Lo studio rappresenta uno strumento prezioso nelle decisioni a riguardo del ruolo rivestito dalla attenuazione naturale nelle opzioni di trattamento, dove la capacità di attenuazione naturale delle acque sotterranee può essere integrata con metodi ingegneristici al fine di ottenere la bonifica del sito.

Numerical model of the behavior of chlorinated ethenes in a fractured, karstic limestone aquifer / Pastore, Nicola; Cherubini, Claudia; Giasi, Concetta I.; Rapti, Dimitra. - In: HYDROGEOLOGY JOURNAL. - ISSN 1431-2174. - STAMPA. - 29:2(2021), pp. 667-686. [10.1007/s10040-020-02248-1]

Numerical model of the behavior of chlorinated ethenes in a fractured, karstic limestone aquifer

Pastore, Nicola
;
Giasi, Concetta I.;
2021-01-01

Abstract

Characterizing the transport and degradation of chlorinated ethenes in fractured aquifers, as well as the assessment of cleanup times, poses an extreme technical challenge. In the presented study, a method to analyze reactive transport and reductive dechlorination of chlorinated solvents in fractured aquifers is developed. A rough-walled parallel-plate model of nonlinear flow behavior is coupled with random-walk particle tracking, incorporating particle exchange between the mobile and stagnant zones, adsorption processes, and reductive dechlorination reaction pathways. The developed methodology, considering reductive dechlorination processes in a Lagrangian framework, is able to simulate the motion of particles affected by first-order network reactions, so that particles move according to their chemical state, affecting physical transport processes (advection, dispersion, mass-transfer exchange between mobile and stagnant zones). The developed model is applied to a case study of groundwater contamination in the industrial area of Bari and Modugno (Italy), where the limestone aquifer has a fractured, karstic nature. The steady-state distribution of the contamination by chlorinated ethenes from a source at a hot spot is obtained and compared with the observed scenario of contamination, in order to estimate the plausible transport and degradation processes and the mass loading at source. The study represents a valuable tool in deciding the role of natural attenuation as a treatment option, where the natural attenuation capacity of groundwater can be integrated with engineering methods in order to obtain site remediation.
2021
Numerical model of the behavior of chlorinated ethenes in a fractured, karstic limestone aquifer / Pastore, Nicola; Cherubini, Claudia; Giasi, Concetta I.; Rapti, Dimitra. - In: HYDROGEOLOGY JOURNAL. - ISSN 1431-2174. - STAMPA. - 29:2(2021), pp. 667-686. [10.1007/s10040-020-02248-1]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/206472
Citazioni
  • Scopus 4
  • ???jsp.display-item.citation.isi??? 4
social impact