<p>This dissertation investigates the factors which affect the removal of arsenic from groundwater by adsorption and coagulation technologies, including the interactions between As and natural organic matter (NOM). Humic acid (HA) was utilised as an NOM analogue, and was shown to be capable of both complexing and oxidising As, depending upon the prevailing conditions. The arsenic removing capabilities of three iron oxide coated sands (IOCS) were investigated, including IOCSW, a waste material from a local drinking water treatment plant generated during the removal of iron and manganese. IOCSW was highly effective at removing both As(V) and As(III) from synthetic water matrices (qmax = 78.3 &micro;g As(V)/g and 99.1 &micro;g As(III)/g). The negative effects of competitive anions (phosphates, silicates and HA) on arsenic removals were not significant enough to preclude the application of IOCSW for arsenic removal during drinking water treatment. The removals of both As and NOM by coagulation and enhanced coagulation with pH correction and preoxidation were also investigated. As(V) &nbsp;was more readily removed by coagulation than As(III), so that the most efficient coagulation treatment investigated for arsenic and NOM removal applied preozonation with subsequent combined coagulation with polyaluminium chloride and ferric chloride. Different groundwaters displayed large variations in the As and NOM removal behaviours. Response surface methodology (RSM) was therefore applied to investigate &nbsp;the interactions between As and NOM during ferric chloride coagulation and optimise their combined removals. Multiple interaction effects were observed during this investigation, highlighting the importance of utilizing RSM to optimise drinking water treatment technologies.</p> / <p>Ova disertacija ispituje faktore koji utiču na uklanjanje arsena iz podzemne vode primenom adsorpcija i koagulacije, uključujući i interakcije između arsena i prirodnih organskih materija (POM). Huminska kiselina (HA) je korisćena kao model za POM, a pokazano je da može i da kompleksira i da oksiduje As, u zavisnosti od eksperimentalnih uslova. Ispitivane su mogućnosti uklanjanja arsena za tri peska obložena gvožđe oksidom (IOCS), uključujući IOCSW, koji je dobijen sa postrojenja za tretman vode za piće i potiče iz procesa uklanjanja gvožđa i mangana. IOCSW se pokazao kao visoko efikasan za uklanjanje As(V) i As(III) iz sintetičkih vodenih matriksa (q_max = 78.3 &micro;g As(V)/g i 99.1 &micro;g As(III)/g). Negativni efekti kompetirajućih jona (fosfata, silikata i HA) na uklanjanje arsena nisu bili dovoljno značajni da bi se isključila primena IOCSW za uklanjanje arsena tokom tretmana vode za piće. Zajedničko uklanjanje As i POM koagulacijom i unapređenom koagulacijom uz pode&scaron;avanje pH i kombinovanje sa oksidacionim predtretmanima je takođe ispitivano. Bolje uklanjanje koagulacijom postignuto je za As(V) u odnosu na As(III), stoga se kao najefikasniji ispitivani koagulacioni tretman pokazalo uklanjanje arsena i POM primenom predozonizacije praćene kombinovanom koagulacijom sa polialuminijum hloridom i gvožđe hloridom. Ispitivanja na različitim podzemnim vodama, pokazala su velike varijacije u pona&scaron;anju As i POM tokom tretmana. Iz tog razloga je primenjena metodologija odzivne povr&scaron;ine (RSM) u cilju ispitivanja interakcija između As i POM tokom koagulacije gvožđe hloridom i optimizacije njihovog kombinovanog uklanjanja. Sagledavanje većeg broja interakcija primenom metodologije odzivne povr&scaron;ine potvrđuje važnost njegove primene pri optimizaciji tretmana vode za piće.</p>

Made available in DSpace on 2017-07-20T12:40:16Z (GMT). No. of bitstreams: 1 Grasiele Cavallini tese.pdf: 2849739 bytes, checksum: 3a66c1a0f56779dc9b4b25e36a7e4b63 (MD5) Previous issue date: 2015-10-23 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study evaluates the use of a pilot filtering double unit, comprising an ascending draining gravel filter and a rapid descending sand filter for the treatment of UASB reactor effluent. As a preliminary phase to the double filtering, coagulation/oxidation was used aiming at helping degradation and flocculation of contaminants, facilitating their retention on the filters. In this phase, three combinations were used: ferrous sulfate (FS) and peracetic acid (APA); ferrous chloride (FC) and CF and APA, all with the same iron concentration. After treatability tests, the efficacy of the system was assessed through the physical-chemical and microbiological parameters. In all treatments carried out in the pilot unit, the suspended solids (SST) were totally removed, which resulted in over 90% turbidity reduction. The treatments in the presence of APA demonstrated higher removal of the effluent color, however, the treatment with FS and APA cannot be recommended due to the high concentration of sulfate ions in the final effluent. Regarding microbiological parameters, the presence of oxidant contributed to the partial inactivation of microorganisms. The alternative to carry out a disinfection phase with APA after double filtering using the coagulant/oxidant FC/APA can be employed without any addition phase to irrigate orchards, pastures and cereal crops according to the NBR 13969/97. By adding the pH adjustment phase and chloride addition to the treatment proposed, the treated effluent can be reused in: agriculture, restrictive agriculture; damming, restrictive damming, environment, industry and the replenishment of underground water (except for drinking purposes), according to the recommendations of the USEPA (2012) Recommendation Manual. / Este trabalho avalia o uso de uma unidade piloto de dupla filtração, composta por filtro de pedregulho de escoamento ascendente e filtro rápido descendente de areia para pós-tratamento de efluente de reator UASB. Como etapa preliminar à dupla filtração utilizou-se a coagulação/oxidação, com o objetivo de auxiliar na degradação e na floculação dos contaminantes, facilitando sua retenção nos filtros. Nesta etapa foram utilizadas três combinações: Sulfato ferroso (SF) e ácido peracético (APA); Cloreto férrico (CF) e CF e APA, todas com a mesma concentração de ferro. Após os ensaios de tratabilidade a eficiência do sistema foi avaliada através de parâmetros físico-químicos e microbiológicos. Em todos os tratamentos realizados na unidade piloto os sólidos em suspensão (SST) foram totalmente removidos o que refletiu em reduções superiores a 90% de turbidez. Os tratamentos com a presença do oxidante APA demonstraram uma remoção maior da cor do efluente, porém o tratamento com SF e APA não pode ser recomendado pela alta concentração de íons sulfato no efluente final. Quanto aos parâmetros microbiológicos, a presença do oxidante contribuiu para a inativação parcial dos microrganismos. A alternativa de realizar a etapa de desinfecção com APA após a dupla filtração com CF também foi avaliada e possibilitou desinfecção total do efluente quanto aos indicadores de contaminação avaliados. Considerando a possibilidade de reúso, o efluente UASB pós-tratado pela dupla filtração utilizando o coagulante/oxidante CF/APA pode ser utilizado sem nenhuma etapa adicional para irrigação de pomares, pastagens e cultivo de cereais de acordo com a NBR 13969/97. Acrescentando a etapa de ajuste de pH e adição de cloro no tratamento proposto o efluente tratado pode ser utilizado para reúsos: agrícola; agrícola restritivo; represamento; represamento restritivo; ambiental; industrial e reabastecimento de águas subterrâneas (reutilização não potável), de acordo com as recomendações do manual de reúso da USEPA (2012).