Thesis (Ph. D.)--Institute of Paper Chemistry, 1966. / Includes bibliographical references (p. 102-106).

No description available.

Thesis (Ph. D.)--University of Oklahoma. / Bibliography: leaves 135-155.

Abstract The large amounts of industrial wastewaters, contaminated by hazardous and toxic compounds together with ever tightening legislation, have challenged traditional wastewater treatment methods. Therefore, the development of discharge limits under, cost-effective and ecological wastewater treatment has become an essential concern. Catalytic water phase technologies are interesting alternatives for traditional wastewater treatment. Among them catalytic wet air oxidation (CWAO) has been used successfully in the management of various industrial effluents. However, the development of an active and stable catalyst for the severe reaction conditions of CWAO has proved truly challenging. The aim of this thesis was to study the activity and stability of laboratory prepared cerium supported metal catalysts in the catalytic wet air and wet peroxide oxidation of aqueous organic pollutants. Ru supported on Ce-Zr mixed oxides and commercial activated carbon as reference were used in CWAO and catalytic wet peroxide oxidation (CWPO) of surface plating industry wastewater. Ag/Ce-Zr and Pt/Ce-Ti catalysts were catalyzed CWAO of aqueous solution of bisphenol A (BPA). Both CWAO and CWPO improved the abatement of organic compounds from surface plating industry wastewater when comparing the non-catalytic experiments. Moreover, catalytic oxidation enhanced the biodegradability of organic matter in the wastewaters. According to the results, Pt/Ce-Ti catalysts performed with higher activity in CWAO of BPA than Ag/Ce-Zr catalysts and almost 100% removal of BPA was achieved. The leaching of active metal during oxidation experiments affected the activity of Ag/Ce-Zr catalysts. Moreover, CWAO of BPA was not a surface area specific reaction but the activity of catalysts was related to the chemisorbed oxygen content on the catalysts’ surface. The results of this thesis showed that cerium supported metal catalysts are active and stable catalysts in CWAO of BPA and also in the treatment of industrial wastewater. Therefore, these catalysts could be applied next to pilot scale applications. / Tiivistelmä Teollisuuden jätevedet sisältävät usein haitallisia ja myrkyllisiä yhdisteitä, joiden käsittely perinteisillä jäteveden käsittelymenetelmillä on hyvin haastavaa. Lisäksi alati kiristyvä ympäristölainsäädäntö asettaa omat vaatimuksensa jäteveden käsittelylle. Katalyyttiset vedenkäsittelymenetelmät ovat viime vuosina herättäneet paljon kiinnostusta. Yksi lupaavimmista tekniikoista on katalyyttinen märkähapetus, jota on käytetty sekä lukuisten malliaineiden että teollisten jätevesien käsittelyssä. Märkähapetuksen vaativissa reaktio-olosuhteissa aktiivisena säilyvän katalyyttimateriaalin kehittäminen on kuitenkin osoittautunut varsin haasteelliseksi. Väitöskirjatutkimuksen tavoitteena oli kehittää aktiivisia ja kestäviä ceriumpohjaisia katalyyttimateriaaleja märkähapetusreaktioon. Tutkimuksessa valmistettiin Ru-, Pt- ja Ag-katalyyttejä, jotka impregnoitiin Ce-Zr- ja Ce-Ti-sekaoksideille. Ru/Ce-Zr-katalyyttejä sekä kaupallista aktiivihiiltä vertailumateriaalina käytettiin pintakäsittelyteollisuuden jäteveden märkähapetuksessa ja märkäperoksidihapetuksessa. Bisfenoli A:n (BPA) vesiliuoksen märkähapetusta katalysoitiin sekä Ag/Ce-Zr- että Pt/Ce-Ti-katalyyteillä. Katalyyttisellä märkähapetuksella ja märkäperoksidihapetuksella pintakäsittelyteollisuuden jäteveden orgaanisten yhdisteiden konsentraatio väheni enemmän verrattuna ilman katalyyttiä suoritettuihin hapetuksiin. Lisäksi käsitellyn vesinäytteen biohajoavuusaste nousi eli jäteveden sisältämät orgaaniset yhdisteet olivat hapettuneet helpommin biohajoavaan muotoon. Pt/Ce-Ti-katalyytit olivat Ag/Ce-Zr-katalyyttejä aktiivisempia BPA:n märkähapetusreaktiossa. Pt-katalyyttisessä reaktiossa saavutettiin lähes 100 % reduktio BPA:n pitoisuudessa. Ag-katalyyttien aktiivisuuteen vaikutti hopean osittainen liukeneminen hapetettavaan liuokseen märkähapetusreaktion aikana. Lisäksi havaittiin, että BPA:n märkähapetusreaktiossa katalyytin aktiivisuus oli riippuvainen katalyyttipintaan kemiallisesti sitoutuneen hapen määrästä eikä niinkään katalyytin pinta-alasta. Väitöskirjatutkimuksessa saatujen tulosten perusteella valmistetut ceriumpohjaiset metallikatalyytit olivat aktiivisia ja kestäviä. Katalysoiduissa hapetusreaktiossa sekä BPA:n että pintakäsittelyteollisuuden jäteveden orgaaninen kuormitus pieneni. Siksi valmistettuja katalyyttimateriaaleja voitaisiin tutkia seuraavaksi pilotti-mittakaavan sovellutuksissa.

<p>Cilj ovog rada je bio da se ispita uticaj ozona i ozon/vodonik-peroksida na efikasnost uklanjanja POM i prekursora oksidacionih nusproizvoda, procesima koagulacije, flokulacije i adsorpcije. Posebna pažnja posvećena je ispitivanju uticaja navedenih procesa na sadržaj prekursora oksidacionih nusproizvoda hlora (trihalometana i halosirćetnih kiselina), kao i na uticaj hipohlorita na formiranje ovih jedinjenja u tretiranoj vodi. Analiza hemijskih karakteristika sirove podzemne vode kori&scaron;ćene u ispitivanjima pokazuje da sadrži visok nivo POM pretežno hidrofobnog karaktera (PB = 37,7&plusmn;0,60 mg KMnO4/l; DOC = 9,27&plusmn;0,92 mg C/l; UV254 = 0,497&plusmn; 0,015 cm-1; SUVA = 5,36&plusmn;0,49 1 mg-1 m-1; PFTHM = 555&plusmn;128 &micro;g/l; PFHAA = 245&plusmn;54,9 &micro;g/l), kao i visoku koncentraciju arsena (51,7&plusmn;16,4 &micro;g/l).<br />Poređenjem uticaja dve ispitivane vrste koagulanata (FeCl3 i FeCl3/PACl) utvrđeno je da imaju različite mehanizme uklanjanja POM i prekursora oksidacionih nusproizvoda. FeCl3/PACl omogućava smanjenje sadržaja POM izraženih preko vrednosti DOC, PB, UV254 apsorbancije i SUVA za 54%, 71%, 88% i 74%, u odnosu na sirovu vodu respektivno, dok se koagulacijom sa FeCl3 postiže smanjenje DOC, PB, UV254 apsorbancije i SUVA za 51%, 48%, 61% i 21%, respektivno. U vodi nakon koagulacije sa FeCl3 zaostaju POM hidrofobnog karaktera (SUVA = 5,12 l m-1 mg-1), dok se POM u koagulisanoj vodi sa FeCl3/PACl, mogu okarakterisati kao hidrofilne (SUVA = 1,70 l m-1 mg-1). Koagulacija sa FeCl3 i FeCl3/PACl omogućila je smanjenje sadržaja arsena u vodi za preko 95%, pri čemu su koncentracije As u koagulisanoj vodi bile niže od 10 &micro;g/l. Ozon i O3/H2O2 proces pokazuju sličnu efikasnost u smanjenju sadržaja POM i prekursora oksidacionih nusproizvoda. Poređenjem kombinovanih tretmana koji obuhvataju oksidacioni predtretman i koagulaciju, utvrđeno je da efikasnost koagulacije sa FeCl3 i FeCl3/PACl u smanjenju vrednosti DOC, PB, UV254, SUVA, PFTHM i aldehida, uglavnom zavisi od mehanizma delovanja samih koagulanata, dok ozon i O3/H2O2 proces doprinose smanjenju vrednosti ovih parametara kroz oksidaciju i izdvajanje lako isparljivih komponenti iz vode stripingom gasa. Sa aspekta promene sadržaja prekursora HAA, ozon i O3/H2O2 proces omogućavaju povećanje efikasnosti procesa koagulacije sa FeCl3 i FeCl3/PACl, u odnosu na koagulaciju bez oksidacionog predtretmana.<br />Kada se uzmu u obzir vrednosti svih navedenih parametara, kao i primenjenje doze oksidacionih sredstava i koagulanata, najbolji rezultati u uklanjanju POM i prekursora oksidacionih nusproizvoda (smanjenje vrednosti DOC za 55%, UV254 i SUVA za vi&scaron;e od 90%, u odnosu na sirovu vodu; PB = 7,70 mg KMnO4/l;&nbsp; PFTHM =158-188 &micro;g/l; PFHAA = 33,0-53,8 &micro;g/l i sadržaj aldehida 16,7-17,9 &micro;g/l) postižu se primenom tretmana koji obuhvataju oksidacioni predtretman ozonom (3,0 g O3/m3), odnosno O3/H2O2&nbsp; (3,3 g O3/m3; H2O2:O3 =1:1), koagulaciju (30 g FeCl3/m3 / 30 g Al/m3) uz recirkulaciju flokulacionog mulja i adsorpciju na zeolitu, flokulaciju, sedimentaciju i filtraciju na pe&scaron;čano/antracitnom filtru.<br />Za zavr&scaron;nu obradu vode GAU filtracijom pre procesa dezinfekcije, na osnovu svih ispitivanih parametara, kao najefikasniji u uklanjanju POM i prekursora oksidacionih nusproizvoda (THM, HAA i aldehida) pokazao se GAU Norit Row 0,8 Supra.<br />Hlorisanjem u simuliranim uslovima dezinfekcije, utvrđeno je da voda dobijena nakon GAU filtracije u ispitivanim tretmanima, ima zadovoljavajući kvalitet sa aspekta sadržaja THM i HAA (sadržaj THM je 69,7-77,4 &micro;g/l; koncentracija DCAA je &lt; MDL) čije su maksimalno dozvoljene koncentracije regulisane u vodi za piće (100 &micro;g/l za THM i 50 &micro;g/l za DCAA).<br />Statističkom obradom podataka iz laboratorijskih i pilot ispitivanja utvrđene su empirijske zavisnosti koje se mogu primenjivati za predviđanje koncentracije THM i HAA u tretiranoj vodi nakon tretmana ispitivanih na pilot postrojenju. Da bi se mogle primeniti za druge vrste vode i drugačije dizajnirane tetmane, neophodno je izvr&scaron;iti validaciju primenom nezavisnog seta podataka.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />Svi rezultati dobijeni u toku istraživanja ukazuju na neophodnost primene oksidacionih sredstava u tretmanu ispitivane podzemne vode. Zbog različitog mehanizma delovanja, neophodno je izvr&scaron;iti odabir odgovarajuće vrste i doze oksidacionog sredstva, kao i koagulanta u tretmanu vode za piće, uzimajući u obzir karakteristika sirove vode i efikasnost koja se želi postići. Primena optimalnih doza ozona i O3/H2O2 omogućava povećanje efikasnosti uklanjanja POM i prekursora oksidacionih nusporizvoda, procesima koagulacije, flokulacije i adsorpcije. Odabirom odgovarajućih uslova tretmana postiže se da i nakon hlorisanja u postupku dezinfekcije, voda zadovoljava kriterijume kvaliteta vode za piće, sa aspekta sadržaja trihalometana i halosirćetnih kiselina.</p> / <p>The aim of this work was to investigate influence of ozone and ozone/hydrogen peroxide on efficiency of coagulation, flocculation and adsorption on natural organic matter and oxidation by-products removal. Special attention was dedicated to investigation of these processes on chlorine oxidation by-products (trihalomethanes and haloacetic acids) as well as on hypochlorite influence on formation of these compounds in treated water. The analysis of chemical characteristics of raw ground water used in this investigation show that it contains high amount of NOM, mainly of hydrophobic nature (PB = 37,7&plusmn;0,60 mg KMnO4/l; DOC = 9,27&plusmn;0,92 mg C/l; UV254 = 0,497&plusmn; 0,015 cm-1; SUVA = 5,36&plusmn;0,49 1 mg-1 m-1; PFTHM = 555&plusmn;128 &mu;g/l; PFHAA = 245&plusmn;54,9 &mu;g/l) as well as high arsenic concentration (51,7&plusmn;16,4 &mu;g/l).<br />Comparing the influences of two investigated coagulants (FeCl3 and FeCl3/PACl) it was observed that they have different mechanisms of NOM and oxidation by-products precursors&rsquo; removal. FeCl3/PACl enables reduction of DOC, PB, UV254 absorbance and SUVA value for 54%, 71%, 88% i 74%, respectively, relative to raw water. Coagulation with FeCl3 provides reduction of DOC, PB, UV254 absorbance and SUVA for 51%, 48%, 61% i 21%, respectively. In water coagulated with FeCl3 remains NOM of hydrophobic nature (SUVA = 5,12 l m-1 mg-1) while NOM in coagulated water with FeCl3/PACl can be characterized as hydrophilic (SUVA = 1,70 l m-1 mg-1). Coagulation with FeCl3 and FeCl3/PACl enables arsenic content reduction for over 95% relative to raw water, with As concentrations in coagulated water below of 10 &mu;g/l. Ozone and O3/H2O2 process demonstrates similar efficiency in NOM and oxidation by-products precursors content reduction. Comparing combined treatment which includes oxidation pretreatment and&nbsp;<span style="font-size: 12px;">coagulation, it was observed that efficiency of coagulation in DOC, PB, UV254, SUVA, PFTHM and aldehydes reduction mainly depends on coagulants activity mechanisms, while ozone and O3/H2O2 process contributes to reduction of these parameters through oxidation and removal of volatile compounds from water by gas stripping. Ozone and O3/H2O2 process enables increase of coagulation efficiency for HAA precursor&rsquo;s removal, comparing to coagulation without oxidation pretreatment.</span></p><p>Taking into account all measured parameters as well as applied doses of oxidation reagents and coagulants, it can be concluded that the best results in NOM and oxidation by-products precursors content reduction (decrease of DOC for 55%, UV254 i SUVA for more then 90%, related to raw water; PB = 7,70 mg KMnO4/l; PFTHM =158-188 &mu;g/l; PFHAA = 33,0-53,8 &mu;g/l and content of aldehydes 16,7-17,9 &mu;g/l) can be obtained by treatments which include oxidation pretreatment with ozone (3,0 g O3/m3), as well as with O3/H2O2 (3,3 g O3/m3; H2O2:O3 =1:1), coagulation (30 g FeCl3/m3 / 30 g Al/m3), with flocculation sludge recirculation and zeolit adsorption, flocculation, sedimentation and filtration on sand/anthracite filter.<br />For the final water treatment with GAC filtration before disinfection process, based on all parameters, GAC Norit Row 0,8 Supra was the most efficient in NOM and oxidation by-products precursors reduction (THM, HAA and aldehydes).<br />After chlorination in simulated disinfection conditions, it was determined that water after GAC filtration in investigated treatments has satisfactory quality in terms of regulated THM and HAA (content of THM is 69,7-77,4 &mu;g/l; concentration of DCAA is &lt; MDL) which maximal allowable level for drinking water is established (100 &mu;g/l for THM and 50 &mu;g/l for DCAA).<br />By statistical analysis of data obtained in laboratory and pilot scale experiments it was determined empirical relations for THM and HAA concentration predictions in treated water.<br />All obtained results in this research indicate that oxidation reagents need to be applied in treatment of investigated ground water. Because of different action mechanism, it is necessary to select the adequate type and dose of oxidation reagent and coagulant in water treatment, taking into account characteristics of raw water and efficiency that needs to be achieved. Application of optimal doses of ozone and O3/H2O2 enables increase of coagulation, flocculation and adsorption efficiency in NOM and oxidation by-products precursors&rsquo; removal. Selection of adequate treatment conditions provides that after chlorination in disinfection process water satisfies drinking water quality criteria, in terms of trihalomethanes and haloacetic acids.</p>

M. Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology / Fenton oxidation is classified into two processes, homogeneous and heterogeneous. Homogeneous Fenton oxidation process, have been shown to be efficient in the degradation of organic pollutants. However, it was shown to have limitations which can be addressed by the heterogeneous Fenton oxidation. Despite the high efficiency of the heterogeneous Fenton oxidation process in the degradation of recalcitrant organic pollutants, the currents synthesis trends of the heterogeneous Fenton catalyst have been proven to be time and energy constraining, since it involves the multi-step were the activated carbon have to be prepared first then co-precipitate the iron oxide on the activated carbon. However, as much as the heterogeneous Fenton catalyst has been proven to have high catalytic activity towards degradation of organic pollutants, these catalysts have some limitations, such limitations include metal ions being leached from the catalyst support into the treated water causing catalyst deactivation and a secondary pollution to the treated water. In this thesis, these catalysts have been applied in the degradation of recalcitrant organic pollutants such as methylene blue and phenols. This study focuses on the single step synthesis of iron oxide nanoparticles supported on activated carbon, were carbonaceous material is impregnated with iron salt then pyrolysed via microwave heating. Microwave power and the amount of iron salt were optimized. The prepared activated carbon-iron oxide composites were applied to the degradation of 2-nitrophenol (2-NP) and methylene blue (MB). Methylene blue was used as a model compound due to the fact that it is easier to monitor the degradation process with UV-Vis as compared to 2-nitrophenol . 2-nitrophenol the additional step for the adjustment of pH is required since nitrophenols are colorless in color at lower pH. The characterization showed that the microwave power and the amount of the iron precursor have an influence on the porosity and surface functional groups of the activated carbon. Further it was vi observed that microwave power and iron precursor influnces the amount of iron oxide formed on the surface of the support. It was also observed that the activated carbon-iron oxide composite have the catalytic effects on the Fenton oxidation process of MB and 2-NP. The parameters such as H2O2, pH, catalyst dose, initial concentration, temperature affect the degradation of both MB and 2-NP. Kinetics studies showed that Fenton is a surface driven reaction since the results fitted the pseudo first order model. The thermodynamics parameters also showed that the reaction is endothermic, spontaneous and is randomized. This implies that the reaction of the degradation of MB and 2-NP is feasible and the catalysts prepared have high catalytic activity. MB and 2-NP were degraded to smaller organic molecules (carboxylic acids). The stability of the catalyst observed to decrease as the number of cycles increased, this is due to the leaching of iron ions from the support material. Hence it was concluded that the activated carbon-iron oxide composite was successfully synthesized and had the high catalytic activity for the degradation of MB and 2-NP.

This thesis examines sulfide oxidation in 4 physically and mineralogically diverse acid sulfate soil (ASS) materials collected from coastal floodplain sites in north-eastern New South Wales. The aim of this study is to gain further understanding of the process of sulfide oxidation in ASS materials, which will allow improved and more effective management strategies to be applied to these materials. The process of sulfide oxidation was examined using laboratory incubation experiments. The oxidation of pyrite was the primary cause of initial acidification of the ASS materials studied. Although the acid volatile sulfur fraction increased in concentration by an order of magnitude over the initial 8 days of incubation, the subsequent oxidation of this fraction did not result in substantial acidification. Sulfate (SO42-) was the dominant sulfur species produced from sulfide oxidation, however, water-soluble SO42- was a poor indicator of the extent of sulfide oxidation. The sulfoxyanion intermediates thiosulfate (S2O32-) and tetrathionate(S4O62-) were only detected in the early stages of incubation, and their relative abundance appeared to be pH dependent. The diminishing presence of these 2 sulfur species as oxidation progressed was indicative that ferric iron (Fe3+) and bacterial catalysis were driving the oxidation processes. The rate of sulfide oxidation, and consequent rate of acidification, was highly dependent on the soil pH and oxygen availability. Accelerated sulfide oxidation was only observed at low pH (i.e. pH < 4.0) when oxygen availability was not limited. The application of sub-optimal amounts of neutralising agents prevented severe soil acidification in the short-term (i.e. up to 2 months), but had little effect on decreasing the rate of sulfide oxidation and acidification in the long-term. Sub-optimal amounts of CaCO3 accelerated sulfide oxidation and acidification of the peaty marcasitic ASS material resulting in elevated soluble Fe and Al concentrations. For some of the ASS materials, sub-optimal applications of seawater-neutralised bauxite refinery residue (SNBRR) also resulted in elevated soluble Al concentrations. The response of partially-oxidised ASS materials to the exclusion of oxygen was variable. The rate of sulfide oxidation, acidification and the production of soluble oxidation products generally decreased markedly when subjected to anoxia. However, especially in highly acidic ASS materials (i.e. pH < 3.5), sulfide oxidation and acidification generally occurred (albeit at much slower rates), most probably due to oxidation by Fe3+. Rapid sulfide re-formation occurred in the peat ASS material that had been oxidised for 63 days, with 0.47% reduced inorganic sulfur (SCR) formed over 60 days of anoxia. Biogeochemical sulfide formation consumes acidity, however, sulfide re-formation was ineffective in reversing acidification under the conditions of this experiment. The peroxide oxidation methods examined were method dependent and substantially underestimated peroxide oxidisable sulfur, sulfidic acidity and net acidity. The precipitation of jarosite during peroxide oxidation was a major factor contributing to the underestimation in these ASS materials. Clay mineral dissolution may contribute towards the underestimation of both sulfidic and net acidity using peroxide oxidation methods. The atmospheric loss of sulfur and acidity was also identified as a possible additional interference. This study has shown that the initial pH of an ASS material is a useful indicator (additional to those already used) of the potential environmental hazard of an ASS material when oxygen is expected to be non-limiting, such as when ASS materials are excavated and stockpiled. The recommended action criteria need to be reassessed as the data indicate that the current criteria are conservative for alkaline and neutral ASS materials, but should be lowered for all acidic ASS materials (i.e. pH < 5.5) to 0.03% sulfide regardless of texture. Alternative strategies are necessary for the management of ASS materials that are subject to oxidation when the addition of optimal rates of neutralising materials cannot be ensured. The treatment of sites containing actual ASS materials by management strategies that rely on oxygen exclusion need to be accompanied by strategies that include either acid neutralisation or containment in order to reduce acid export from the site. The peroxide oxidation methods examined were subject to substantial interferences, and consequently are unable to reliably provide accurate measurements of the reduced inorganic sulfur fraction, sulfidic acidity, and net acidity in ASS materials.

This thesis examines sulfide oxidation in 4 physically and mineralogically diverse acid sulfate soil (ASS) materials collected from coastal floodplain sites in north-eastern New South Wales. The aim of this study is to gain further understanding of the process of sulfide oxidation in ASS materials, which will allow improved and more effective management strategies to be applied to these materials. The process of sulfide oxidation was examined using laboratory incubation experiments. The oxidation of pyrite was the primary cause of initial acidification of the ASS materials studied. Although the acid volatile sulfur fraction increased in concentration by an order of magnitude over the initial 8 days of incubation, the subsequent oxidation of this fraction did not result in substantial acidification. Sulfate (SO42-) was the dominant sulfur species produced from sulfide oxidation, however, water-soluble SO42- was a poor indicator of the extent of sulfide oxidation. The sulfoxyanion intermediates thiosulfate (S2O32-) and tetrathionate(S4O62-) were only detected in the early stages of incubation, and their relative abundance appeared to be pH dependent. The diminishing presence of these 2 sulfur species as oxidation progressed was indicative that ferric iron (Fe3+) and bacterial catalysis were driving the oxidation processes. The rate of sulfide oxidation, and consequent rate of acidification, was highly dependent on the soil pH and oxygen availability. Accelerated sulfide oxidation was only observed at low pH (i.e. pH < 4.0) when oxygen availability was not limited. The application of sub-optimal amounts of neutralising agents prevented severe soil acidification in the short-term (i.e. up to 2 months), but had little effect on decreasing the rate of sulfide oxidation and acidification in the long-term. Sub-optimal amounts of CaCO3 accelerated sulfide oxidation and acidification of the peaty marcasitic ASS material resulting in elevated soluble Fe and Al concentrations. For some of the ASS materials, sub-optimal applications of seawater-neutralised bauxite refinery residue (SNBRR) also resulted in elevated soluble Al concentrations. The response of partially-oxidised ASS materials to the exclusion of oxygen was variable. The rate of sulfide oxidation, acidification and the production of soluble oxidation products generally decreased markedly when subjected to anoxia. However, especially in highly acidic ASS materials (i.e. pH < 3.5), sulfide oxidation and acidification generally occurred (albeit at much slower rates), most probably due to oxidation by Fe3+. Rapid sulfide re-formation occurred in the peat ASS material that had been oxidised for 63 days, with 0.47% reduced inorganic sulfur (SCR) formed over 60 days of anoxia. Biogeochemical sulfide formation consumes acidity, however, sulfide re-formation was ineffective in reversing acidification under the conditions of this experiment. The peroxide oxidation methods examined were method dependent and substantially underestimated peroxide oxidisable sulfur, sulfidic acidity and net acidity. The precipitation of jarosite during peroxide oxidation was a major factor contributing to the underestimation in these ASS materials. Clay mineral dissolution may contribute towards the underestimation of both sulfidic and net acidity using peroxide oxidation methods. The atmospheric loss of sulfur and acidity was also identified as a possible additional interference. This study has shown that the initial pH of an ASS material is a useful indicator (additional to those already used) of the potential environmental hazard of an ASS material when oxygen is expected to be non-limiting, such as when ASS materials are excavated and stockpiled. The recommended action criteria need to be reassessed as the data indicate that the current criteria are conservative for alkaline and neutral ASS materials, but should be lowered for all acidic ASS materials (i.e. pH < 5.5) to 0.03% sulfide regardless of texture. Alternative strategies are necessary for the management of ASS materials that are subject to oxidation when the addition of optimal rates of neutralising materials cannot be ensured. The treatment of sites containing actual ASS materials by management strategies that rely on oxygen exclusion need to be accompanied by strategies that include either acid neutralisation or containment in order to reduce acid export from the site. The peroxide oxidation methods examined were subject to substantial interferences, and consequently are unable to reliably provide accurate measurements of the reduced inorganic sulfur fraction, sulfidic acidity, and net acidity in ASS materials.