Carbonate Contamination Research Articles

The effects of carbonate contamination on Ni-Cu-PGE deposit genesis in the Platreef, northern Bushveld Complex: A case study using Niggli numbers

Crustal contamination in Ni-Cu-PGE deposit genesis is generally regarded as an essential, or at least highly beneficial, process in triggering sulfide saturation, either through the addition of external sulfur or as a mechanism for increasing oxygen fugacity through the incorporation of volatile-rich lithologies. The Platreef, northern limb of the Bushveld Complex, South Africa, forms one of the world's largest resources of platinum-group elements (PGE), with additional Ni-Cu-Co mineralisation, and represents a unique deposit, intersecting numerous footwall lithologies from the underlying Transvaal Supergroup. In this study, Niggli Numbers, a geochemical tool used to classify rocks on the molecular proportions of their major element geochemistry, are used to examine the degree and styles of contamination in the Platreef at three locations: Tweefontein, Overysel, and a newly drilled deeper section at Sandsloot. The potential impact of these varying contamination styles on PGE-Ni-Cu mineralisation is then discussed. At Tweefontein and Overysel, the highest PGE-Ni-Cu grades are found in largely uncontaminated pyroxenites, exemplified by Niggli c values <20. Where carbonate contamination is strong, and Niggli c exceeds 30, it is not associated with elevated grades. In contrast, at Sandsloot elevated PGE and Ni grades are strongly associated with carbonate contamination, with Niggli c commonly exceeding 20, and Niggli mg exceeding 0.8, indicating dolomitic contamination, in the highest-grade horizons. Although other pre-emplacement models may yet explain the elevated grades observed at Sandsloot, there remains a clear correlation between interactions with the Malmani dolomite and elevated Ni-Cu-PGE contents which warrants further investigation.

Calibrating ITC instruments: Problems with weak base neutralization

Modern isothermal titration calorimetry instruments give great precision, but for comparable accuracy they require chemical calibration. For the heat factor, one recommended process is HCl into the weak base TRIS. In studying this reaction with a VP-ITC and two Nano-ITCs, we have encountered some problems, most importantly a titrant volume shortfall Δv ≈ 0.3 μL, which we attribute to diffusive loss of HCl in the syringe tip. This interpretation is supported by a mathematical treatment of the diffusion problem. The effect was discovered through a variable-v protocol, which thus should be used to properly allow for it in any reaction that similarly approaches completion. We also find that the effects from carbonate contamination and from OH− from weak base hydrolysis can be more significant that previously thought. To facilitate proper weighting in the least-squares fitting of data, we have estimated data variance functions from replicate data. All three instruments have low-signal precision of σ ≈ 1 μJ; titrant volume uncertainty is a factor of ∼2 larger for the Nano-ITCs than for the VP-ITC. The final heat factors remain uncertain by more than the ∼1 % precision of the instruments and are unduly sensitive to the HCl concentration.

The influence of carbonate on the adsorption performance and mechanism of LDHs toward Cd and As

The excellent adsorption performance of layered double hydroxides (LDHs) toward heavy metals (HMs) had been demonstrated. The carbonate contamination was one of the inherent problems for LDHs whether during the synthesis or application procedure, which significantly affected the adsorption performance of LDHs toward HMs. However, a few studies investigated the mutual effect and mechanism between HMs on LDHs with carbonate interference, especially for the coexistence system of cationic and anionic HMs. In this study, cadmium (Cd) and arsenate (As) were selected as typical cationic and anionic HMs to study the influences of carbonates on their adsorption performance on LDHs. The carbonate intercalated LDHs (CLDH) promoted Cd adsorption but inhibited As adsorption in single system. The adsorption capacity of Cd increased by ∼ 50 % while As adsorption decreased by half. CdCO3 precipitation contributed to ∼ 40 % of the adsorbed Cd whereas weaker electrostatic adsorption inhibited As adsorption due to lower surface zeta potentials of CLDH than LDH. In contrast, both adsorption capacities and rates of Cd and As on CLDH were promoted in binary system (the co-existence of Cd and As) compared with single system. The surface potentials of CLDH turned from positive to negative with As rapid occupation, facilitating Cd entrance into the interlayers. And then the opening of the interlayer space and rearrangement of CLDH enhanced CdCO3 precipitation and isomorphic substitution. With the increase of surface zeta potentials and rearrangement of CLDH, in turn, the adsorption of As was promoted via electrostatic adsorption (∼65 %) and surface complexation (∼35 %). The adsorption capacity of Cd increased by ∼ 15 % whereas As adsorption decreased by half with increasing pH from 4 to 9 in binary system. In contrast, temperature (15–35 ℃) had negligible influence on the adsorption of CLDH toward Cd and As. Herein, this study illustrated the influence mechanism of carbonate intercalation on the simultaneous immobilization of Cd and As on LDHs, providing an understanding for fates of Cd and As with LDHs in more realistic scenes.

Thermal Enhancement of Product Conductivity Raises Capacity in Solid-State Li-O2 Batteries

Li-O2 batteries are mainly limited by the poor conductivity of their discharge products as well as parasitic reactions with carbon-containing electrodes and electrolytes. Here, Li-O2 cells utilizing inorganic solid-state electrolytes are investigated as a means to operate at elevated temperature, thereby increasing the conductivity of discharge products. Growth of dense, conductive LixOy products further removes the need for high-surface area support structures commonly made of carbon. Patterned Au electrodes, evaporated onto Li7La3Zr2O12 (LLZO) solid electrolyte, are used to create a triple-phase boundary for the nucleation of the discharge product, with growth outward into the cell headspace with gaseous O2. Through capacity measurements and imaging, discharge product growths are estimated to reach a critical dimension of approximately 10 μm, far exceeding what would be possible for a conformal film based on its room temperature electronic conductivity. Raman spectroscopy and electrochemical mass spectrometry are used to characterize the discharge chemistry and reveal a mixed lithium oxide character, with evidence of trace lithium hydroxides and initial carbonate contamination. These results showcase that thermal enhancement of Li-O2 batteries could be a viable strategy to increase capacity when paired with solid electrolytes.

Simple and cost-effective mass production of nitrate type MgAl layered double hydroxide: Titration from concentrated solution

A mass production of nitrate type Mg/Al layered double hydroxide was examined by co-precipitation from solution by the titration of concentrated solution of metal salts with ammonium hydroxide under ambient atmosphere. The influence of the suspension pH and post precipitation aging on the products was studied. Over five grams of single-phase nitrate type Mg/Al layered double hydroxide was obtained from a hundred-milliliter suspension (initial concentration of metal salt solution of 1.6 M), which corresponded to 97% yield from the metal ion consumption. Well-defined platy particles of nitrate type Mg/Al layered double hydroxide nanoparticles were obtained by applying post precipitation aging at 80 °C under ambient atmosphere. The sample preparation has been carried out without any caution to remove carbonate contamination to obtain nitrate type Mg/Al layered double hydroxide.

Structural evolution and electrolyte engineering for tri-electrolyte zinc-air cells

Zinc air cell (ZAC) is a promising alternative for Li-ion battery owing to its superior energy density, while it suffers from alkaline electrolyte related issues. Here, a tri-electrolyte microfluidic zinc-air cells are developed based on structural evolution and electrolyte engineering. By strategically using acidic catholyte instead of alkalis, the device performance is largely improved and stabilized, benefiting from 0.8V higher cathodic reaction potential and prohibited carbonate contamination. Since alkalis are still preferred for the anolyte, a third bridge-electrolyte is applied to avoid the neutralization of two electrolytes. To avoid using membranes, a microfluidic cell configuration is further integrated. Without the ion-restriction of the membranes, H2SO4 becomes applicable for catholyte and contributes to a stable operation with further improved potential of 2.18 V. Furthermore, the electrolyte mixing behavior is investigated from both experimental and simulation aspects, which demonstrates the recyclability of the electrolytes and provides guidance for the real application.

Carbonate-free CoAl layered double hydroxides supercapacitors: Controlled precipitation via acid mediated decomplexation

Layered double hydroxides (LDH) belong to a class of highly versatile compounds used in a myriad of applications such as energy storage, catalysis, heavy metal adsorption, etc. Given the high tunability of its structure, ranging from different metal cations to different types of intercalations, LDH can be readily customised to suit the intended applications. One of the inherent problem of LDH lies in their carbonate contamination. The presence of CO32− anions in the intercalation greatly affects the versatility and tunability of LDH. Carbonate intercalation also poses as an interfering species for reactions involving carbonate as intermediates or final products. Unfortunately, existing synthesis procedures of LDH produce either carbonates during the precipitating process or poorly crystallised LDH that absorbs atmospheric carbon dioxide to form carbonates during the drying process; either way results in carbonate contaminated LDH. In this work, we address the problem with the use of ethylenediamine (EDA) complexation followed by controlled decomplexation to prepare CoAl LDH (LDH-EDA). It is shown that the obtained LDH-EDA is carbonate-free and outperforms the CoAl LDH obtained using conventional urea method (LDH-Urea) in terms of crystallinity, surface area and pseudocapacitive properties. Through a detailed experimental and computational study of the preparation mechanism, we propose that ammonium nitrate acts as an acid that mediates the decomplexation of the cobalt (II) trisethylenediamine complex, freeing Co2+ ion in a control manner for the second precipitation process. The multistep process has allowed a controlled rate of formation of LDH, resulting in the highly crystalline LDH-EDA microstructures with pure nitrate intercalation and a flower-like morphology.

Sakurai’s Object revisited: new laboratory data for carbonates and melilites suggest the carrier of 6.9-μm excess absorption is a carbonate

ABSTRACTWe present new room-temperature 1100–1800-cm−1 spectra of melilite silicates and 600–2000-cm−1 spectra of three randomly orientated fine-grained carbonates to determine the possible carrier(s) of a 6.9-μm absorption feature observed in a variety of dense astronomical environments, including young stellar objects and molecular clouds. We focus on the low-mass post-asymptotic giant branch star Sakurai’s Object, which has been forming substantial quantities of carbonaceous dust since an eruptive event in the 1990s. Large melilite grains cannot be responsible for the 6.9-μm absorption feature because the similarly shaped feature in the laboratory spectrum was produced by very low (0.1 per cent by mass) carbonate contamination, which was not detected at other wavelengths. Due to the high band strength of the 6.9-μm feature in carbonates, we conclude that carbonates carry the astronomical 6.9-μm feature. Replacement of melilite with carbonates in models of Sakurai’s Object improves fits to the 6–7-μm Spitzer spectra without significantly altering other conclusions of Bowey’s previous models except that there is no link between the feature and the abundance of melilite in meteorites. With magnesite (MgCO3), the abundance of 25-μm-sized SiC grains is increased by 10–50 per cent and better constrained. The mass of carbonate dust is similar to the mass of polycyclic aromatic hydrocarbon dust. Existing experiments suggest that carbonates are stable below 700 K; however, it is difficult to ascertain the applicability of these experiments to astronomical environments, and more studies are required.

DO WEAK OR STRONG ACIDS REMOVE CARBONATE CONTAMINATION FROM ANCIENT TOOTH ENAMEL MORE EFFECTIVELY? THE EFFECT OF ACID PRETREATMENT ON RADIOCARBON AND δ13C ANALYSES

ABSTRACTIn hot environments, collagen, which is normally targeted when radiocarbon (14C) dating bone, rapidly degrades. With little other skeletal material suitable for 14C dating, it can be impossible to obtain dates directly on skeletal materials. A small amount of carbonate occurs in hydroxyapatite, the mineral phase of bone and tooth enamel, and has been used as an alternative to collagen. Unfortunately, the mineral phase is often heavily contaminated with exogenous carbonate causing 14C dates to underestimate the true age of a sample. Although tooth enamel, with its larger, more stable crystals and lower porosity, is likely to be more robust to diagenesis than bone, little work has been undertaken to investigate how exogenous carbonate can be effectively removed prior to 14C dating. Typically, acid is used to dissolve calcite and etch the surface of the enamel, but it is unclear which acid is most effective. This study repeats and extends earlier work using a wider range of samples and acids and chelating agents (hydrochloric, lactic, acetic and propionic acids, and EDTA). We find that weaker acids remove carbonate contaminants more effectively than stronger acids, and acetic acid is the most effective. However, accurate dates cannot always be obtained.

The Roman amphitheatre in Mérida, Spain ˗Augustan or Flavian? Radiocarbon dating results on mortar carbonate

Abstract Four lime mortar samples from the Mérida amphitheatre in Spain were dated in 2001 and re-dated in 2019 with refined dating methods and focus on carbon dioxide that was released in late CO2 fractions when dissolved in phosphoric acid. The samples were difficult to date because they contained highly soluble, young carbonate contamination that dominated the carbon dioxide from the early stages of the reaction with the acid in the hydrolysis process. They were also rather hydraulic and rich in magnesium, which could have caused delayed hardening. However, there was very little dead carbon contamination so that late carbon dioxide fraction gave uniform 14C ages, pointing to a late 1st c. AD Flavian, or later age of the amphitheatre.

The Effects of H3PO4 Treatment on Li/Mn-Rich Layered Li1.2-X[Mn0.55Ni0.15Fe0.10]O2(1-x)F2x Cathode Materials for Li-Ion Batteries

In this study, sol-gel synthesized Li/Mn-rich layered Li1.2-x[Mn0.55Ni0.15Fe0.10]O2(1-x)F2x was studied as an alternative to commercial NMC and LiCoO2 batteries due to greater theoretical capacity ~250 mAh g-1, increased safety, and lower-cost. Despite these advantages, MNF cathodes show experimentally lower capacity and decay, voltage fading, and poor rate capability [1]. To address these problems, the creation of a Li3PO4-coating with a H3PO4 solution treatment was investigated. Treatment has resulted in increased initial discharge capacity for the first 3 cycles at 0.1C and increased cell retention for the following 97 cycles at 0.33C compared to untreated MNF551510. As alternatives to the classic NMC and LiCoO2 arise, H3PO4 treatment can be a useful technique to enhance electrochemical performance of novel cathode materials.Powder X-ray diffraction was used to determine the phase of the material as well as the amount of lithium carbonate contamination before and after Li3PO4-coating. Furthermore, scanning electron microscopy (SEM) was performed to analyze the effects of Li3PO4-coating on the morphology of the particle. For electrochemical analysis, galvanostatic charge-discharge cycling and cyclic voltammetry (CV) were completed.

Green Synthesis of Hydrocalumite (CaAl-OH-LDH) from Ca(OH)2 and Al(OH)3 and the Parameters That Influence Its Formation and Speciation

Hydrocalumite is a layered double hydroxide (LDH) that is finding increased application in numerous scientific fields. Typically, this material is produced through environmentally polluting methods such as co-precipitation, sol-gel synthesis and urea-hydrolysis. Here, the hydrothermal green (environmentally friendly) synthesis of hydrocalumite (CaAl-OH) from Ca(OH)2 and Al(OH)3 in water and the parameters that influence its formation are discussed. The parameters investigated include the reaction temperature, reaction time, molar calcium-to-aluminium ratio, the morphology/crystallinity of reactants used, mixing and the water-to-solids ratio. Hydrocalumite formation was favoured in all experiments, making up between approximately 50% and 85% of the final crystalline phases obtained. Factors that were found to encourage higher hydrocalumite purity include a low water-to-solids ratio, an increase in the reaction time, sufficient mixing, the use of amorphous Al(OH)3 with a high surface area, reaction at an adequate temperature and, most surprisingly, the use of a calcium-to-aluminium ratio that stoichiometrically favours katoite formation. X-ray diffraction (XRD) and Rietveld refinement were used to determine the composition and crystal structures of the materials formed. Scanning electron microscopy (SEM) was used to determine morphological differences and Fourier-transform infrared analysis with attenuated total reflectance (FTIR-ATR) was used to identify possible carbonate contamination, inter alia. While the synthesis was conducted in an inert environment, some carbonate contamination could not be avoided. A thorough discussion on the topic of carbonate contamination in the hydrothermal synthesis of hydrocalumite was given, and the route to improved conversion as well as the possible reaction pathway were discussed.

Phosphorus reclamation by end-of-pipe recovery as calcium phosphate from effluent of wastewater treatment plants of agroindustry

Phosphorus is essential for live and must be recovered from all possible secondary resources. One of these secondary resources may be the effluent of a wastewater treatment plant in which no obvious measures are taken to remove or recover the phosphorus. Effluent water of the wastewater treatment facility of a potato processor was spiked with 40–50 mg phosphate-P.L−1 to simulate such a water that can be subjected to an end-of-pipe recovery of phosphate. Simulations with PHREEQC were calculated and batch experiments were performed. Continuously stirred tank reactors (CSTR) were fed with P-spiked effluent. Increasing the Ca/P ratio promoted calcium phosphate precipitation but increased also the calcium carbonate contamination. With calcium added in fourfold excess relative to endogenous phosphate-P concentration, 90 % removal can be obtained. For the recovery of phosphorus from this purified effluent the same Ca/P ratio is necessary than in the case where phosphorus is recovered from nitrified UASB effluent. The recovery is stimulated by aeration, which however should not be continuous and by the addition of 5 g L−1 hydroxyapatite and reaches up to 95 %. In contrast to what was expected based upon the batch experiments, but in agreement with the simulations, the precipitates contained up to 6 m% magnesium phosphate, which probably can further be reduced by using shorter hydraulic retention times in the reactor.

Effect of Sodium Carbonate and Bicarbonate Contamination on the Rheological Properties of Water Based Mud

Effect of Sodium Carbonate and Bicarbonate Contamination on the Rheological Properties of Water Based Mud

Phosphorous recovery as calcium phosphate from UASB effluent after nitrification with or without subsequent denitrification

Abstract Wastewater of potato processors contains high amounts of phosphorus and its recovery as calcium phosphate (CP) is investigated. In contrast to struvite, CP can be cotreated with phosphorous ore in phosphoric acid production, as far as it does not contain too much magnesium phosphate. The precipitation of CP was studied from the effluent of an upstream anaerobic sludge blanket reactor (UASB) after lab scale nitrification or lab scale nitrification and denitrification by batch experiments and continuous experiments. Nitrification excludes the possibility of struvite precipitation but did not result in complete removal of dissolved inorganic carbon (DIC). Only a narrow window at neutral pH is available for magnesium-free calcium phosphate precipitation. The additional denitrification caused a pH increase, which resulted in an unwanted magnesium phosphate precipitation and an increase in DIC, causing an increase of calcium carbonate contamination. The saturation index (SI) of CP can be enhanced by increasing the molar Ca/P ratio in the effluent, but this enhances also the contamination with calcium carbonate. Calcium chloride added in a tenfold molar excess relative to the phosphate-P concentration (a total molar Ca/P ratio of about 13) to nitrified effluent resulted in a phosphate recovery as CP of 83 %, but in all conditions, it was difficult to obtain carbonate-free CP.

Source and evolution of ore fluids in the Zhenyuan orogenic gold deposit, SE Tibet: Constraints from the S-C-O isotopes

Orogenic gold deposits commonly have large variation of stable isotopic values of ore minerals induced by complicated ore fluid evolution, which was considered to provide equivocal evidence for ore sources. In contrast, this study has revealed relatively narrow range of S and C-O isotopes of pyrites and carbonate minerals in the Zhenyuan gold deposit (>100 t, at 3.5 g/t) on Ailaoshan shear zone, southeastern margin of Tibet. The Zhenyuan deposit is a disseminated orogenic gold deposit with mineralization and alteration occurring in various types of wall rocks including carbonaceous slate, meta-quartz sandstone, lamprophyre, quartz porphyry and meta-basalt. The pre-ore pyrites include the diagenetic pyrites in carbonaceous slate and meta-quartz sandstone and the barren hydrothermal pyrites in quartz porphyry. Diagenetic pyrites have much varied δ34S values from −54.58 to 38.31‰, and barren hydrothermal pyrites have elevated positive δ34S values (8.76–43.24‰). The ore-related pyrites, disseminated in all types of host rocks and commonly with repetitive gold-rich zones, are the most important gold-bearing minerals. They contain high concentration of Au along with other trace elements, including Cu, As, Sb, Tl, Pb and Bi. Little difference of δ34S values is observed for the pyrites in different types of host rocks and for the low-Au and high-Au zones in single pyrite grain. All ore-related pyrites display a relatively narrow range of δ34S values (−5.22 to 4.16‰) with a peak at ~0‰. This narrow range implies that the deposition of gold from ore fluids at Zhenyuan deposit was mainly controlled by sulfidation of iron-bearing minerals in the wall rocks. The δ34S values of ore-related pyrites are consistent with the explanation that the ore fluids were from the subcrustal source, instead of the crustal source with much varied sulfide δ34S values. Carbonate minerals from different types of host rocks also have consistent and relatively narrow range of δ13CPDB (−3.77 to 0.68‰) and δ18OSMOW (14.85–20.77‰) values, indicating that the composition of ore fluids were little affected by water-rock reaction at deposit scale. The δ13CPDB and δ18OSMOW values of carbonates minerals are between those of the mantle peridotite and marine carbonates, which can be explained by that the ore fluids have experienced crustal carbonate contamination in the subcrustal level or/and along the migration conduit of the ore fluids.

Influence of industrial contamination in municipal secondary effluent disinfection by UV/H2O2.

Advanced oxidation processes, including UV/H2O2, are methods able to remove diverse classes of organic contaminants and disinfect water and wastewater. However, the variation in the matrix composition can influence the inactivation of microorganisms due to the presence of competing reactive material, which consumes the available oxidants. This problem can lead to the use of inadequate oxidant/radiation dose and disturb a correct treatment. The aim of this study was to assess the efficiency of UV/H2O2 to inactivate microbiological indicators in secondary effluents in the presence of high concentration of carbonate, nitrate, metals, and industrial organic contaminants. Metals had a positive influence on inactivation acting as catalysts. Zn, Fe, and all metals simultaneously presented toxic effects to the indicator organisms in the higher concentrations before the treatment. Even in metals presence, the negative effect of carbonate and the industrial organic contaminants on indicators inactivation was very important. Bacteria regrowth after 72h was also affected by the same inhibiting substances, but the metals acted positively inhibiting it. The disinfection indicators had different sensibilities to the spiked substances. Escherichia coli inactivation was more affected than total coliforms by the presence of the industrial contamination, which can lead to different interpretation of inhibition degree depending of the used disinfection indicator.

Sr and Mg isotope geochemistry of the basal Ediacaran cap limestone sequence of Mongolia: Implications for carbonate diagenesis, mixing of glacial meltwaters, and seawater chemistry in the aftermath of Snowball Earth

The seawater chemistry and oceanographic information associated with Snowball Earth are commonly inferred from the geochemistry of cap carbonates deposited on continental margins during and after deglaciation. However, interpretation of such records can be complicated by carbonate diagenesis and contamination from siliciclastic components. In an attempt to disentangle these effects, we studied the geochemistry of the post-Marinoan cap carbonate sequence from Mongolia using a step-leaching procedure, which revealed that most samples are heterogeneous with respect to multiple geochemical signatures, including trace element concentrations, Sr, Mg, C and O isotopic signatures, raising questions to previous studies applying carbonate bulk-rock geochemistry for paleoenvironment reconstructions. Such sample heterogeneity can be explained by contamination from non-carbonate phases and carbonate alteration. After stepped leaching, the least-altered/contaminated geochemical signatures for each sample were identified and the influences of carbonate diagenesis were evaluated. Our data indicate that mixing of glacial meltwater persisted to the maximum flooding surface within the cap carbonate sequence, below which carbonates record significant Mg and Sr isotope fluxuations that are most readily interpreted in the context of the mixing of water masses having distinct isotopic compositions. Only limestones deposited above the maximum flooding surface formed in a well-mixed ocean and exhibit Mg and Sr isotope values that record the integrated effects of Snowball Earth on ocean chemistry. Our study cautions against interpreting the geochemistry of cap carbonates in terms of whole ocean geochemical cycles.

X-Ray Spectroscopic Characterization of BaO, Ba(OH)2, BaCO3, and Ba(NO3)2

Simple inorganic barium compounds are difficult to study spectroscopically in the surface sensitive soft X-ray regime due to significant surface contamination that can dominate the spectra. Here we present a near-edge X-ray absorption (NEXAFS) and X-ray photoelectron spectroscopic (XPS) study of four barium compounds: BaO, Ba(OH)2, BaCO3, and Ba(NO3)2. Using an ambient-pressure XPS instrument we prepared thin film samples in situ, which provided a high degree of control over the surface chemistry and significantly reduced the amount of contamination. The O K-edge spectrum for BaO presented here is in excellent agreement with the latest calculations in the literature, and indicates that experimental spectra in the literature for this compound may have suffered from carbonate contamination.

Disinfection of secondary effluents by O3, O3/H2O2 and UV/H2O2: Influence of carbonate, nitrate, industrial contaminants and regrowth

The objective of this work was to verify the efficiency of O3, O3/H2O2 and UV/H2O2 treatments to disinfect municipal effluents as well as to verify the influence of carbonate, nitrate and industrial contaminants on the disinfection and reactivation of total coliforms and Escherichia coli after the treatments. The results showed that all AOP treatments were affected by the presence of carbonate and nitrate. In general, they reduced the inactivation of total coliforms and E. coli. However, carbonate was the main inhibitor of disinfection. Ozone disinfection showed to be more affected by scavenging compounds than the other methods The choice of the disinfection indicator is very important for the correct assessment of disinfection reduction by scavengers. Industrial contaminants also acted as radical scavengers. However, their influence was very limited. To assess the bacteria reactivation after the treatments the wastewater was kept in bottles for 24 h. Among the three tested oxidation processes, the ozone-alone was the less efficient regarding the bacteria reactivation. It seems that the presence of scavenging can change the mechanism of inactivation and promote faster regrowth.