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1.
J Hazard Mater ; 421: 126677, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34332476

RESUMO

The co-management of different wastewater matrices can lead to synergistic effects in terms of pollutants removal. Here, the co-treatment of real municipal wastewater (MWW) and acid mine drainage (AMD) is comprehensively examined. Under the identified optimum co-treatment condition, i.e., 15 min contact time, 1:7 AMD to MWW liquid-to-liquid ratio, and ambient temperature and pH, the metal content of AMD (e.g., Al, Fe, Mn, Zn) was grossly (~95%) reduced along with sulphate (~92%), while MWW's phosphate content was practically removed (≥99%). The PHREEQC geochemical model predicted the formation of (oxy)-hydroxides, (oxy)-hydro-sulphates, metals hydroxides, and other mineral phases in the produced sludge, which were confirmed using state-of-the-art analytical techniques such as FE-SEM-EDS and XRD. The key mechanisms governing pollutants removal include dilution, precipitation, co-precipitation, adsorption, and crystallization. Beneficiation and valorisation of the produced sludge and co-treated effluent could promote resource recovery paradigms in wastewater management. Overall, the co-treatment of AMD and MWW appear to be feasible, yet not practical due to the excessive volume of MWW that is required to attain the desired treatment quality. Future research could focus on chemical addition for the control of the pH and the use of (photo)-Fenton for enhancing treatment efficiency.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Concentração de Íons de Hidrogênio , Mineração , Fosfatos , Esgotos , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/análise
2.
J Hazard Mater ; 421: 126736, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34333411

RESUMO

Nitrogen removal from mainstream wastewater via DEnitrifying AMmonium OXidation (DEAMOX) is often challenged by undulated actual temperature and high loading rate. Here, we discovered NH2OH addition (HA) and bio-augmentation (BA) tactics on start-up and operation performance of DEAMOXs (R1 and R2) under ambient temperature (11.3-31.7 °C). Over 340-day operation suggested that R2 received 10 mg/L HA and 1:25 BA ratio (v/v, anammox/partial denitrification sludge) achieved desirable nitrogen removal efficiency (NRE) of 97.22% after 145-day, while R1 under higher BA ratio of 1:12.5 without HA obtained lower NRE (90.86%) after 184-day. Batch tests revealed that nitrate-nitrite transformation ratio reached 98.64% at low COD/NO3--N of 2.6 with HA. Significantly, compared with R2, R1 recovered quickly with satisfactory effluent total nitrogen of 4.21 mg/L despite nitrogen loading rate greater than 0.15 kg N/m3/d and temperature decreased to 14.6 °C. The abundant narG represented high nitrate reduction potential, hzsA and hdh were extensively detected as the symbolisation of anammox metabolism. Thauera, Denitratisoma and unclassified f Comamonadaceae dominated nitrite accumulation. Ca. Brocadia as the dominant anammox bacteria, and its population maintained stable against low temperature and load shocks by NH2OH intensification. Overall, this study offers an opportunity for the wide-applications of DEAMOX treating mainstream wastewater.


Assuntos
Compostos de Amônio , Desnitrificação , Reatores Biológicos , Hidroxilamina , Hidroxilaminas , Nitrogênio/análise , Oxirredução , Esgotos , Temperatura , Águas Residuárias
3.
J Environ Manage ; 301: 113793, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34601347

RESUMO

Municipal wastewater treatment plants (WWTPs) have been regarded as the main receptors of microplastics in industrial and domestic wastewater. The excess sludge they generate is an important carrier for the microplastics to enter the environment. In China, relevant regional studies are still in an initial phase. In this work, microplastics in the sewage sludges at different sampling points of five WWTPs in Nanjing City (an important city in the Yangtze River basin) were investigated, including their abundance, morphology and chemical composition. Furthermore, the influence factors such as population density, economic development level, wastewater source and treatment process were also discussed. The analysis results through optical microscope and FT-IR showed that the detected microplastics were divided into fragments, films, fibers and granules. Their chemical component reached up to 19 species, including small amounts of petroleum resins which was scarcely detected in other studies. Wastewater source was the primary factor influencing the microplastic abundance and size in sludge. And the microplastic shape and chemical components were closely related to the industrial type. Furthermore, because the removal effect on the microplastics with different morphologies were varied with the treatment process, the preliminary suggestions on the technology for particular wastewater were proposed. This study provides partial regional data and analysis for the microplastics contained in the sludge of WWTPs, expecting to provide a certain theoretical support for the operations management of WWTPs and standardized sludge treatment.


Assuntos
Poluentes Químicos da Água , Purificação da Água , China , Monitoramento Ambiental , Microplásticos , Plásticos , Esgotos , Espectroscopia de Infravermelho com Transformada de Fourier , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Poluentes Químicos da Água/análise
4.
J Environ Manage ; 301: 113867, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34607143

RESUMO

A mathematical model, which was previously developed for submerged aerobic membrane bioreactors, was successfully applied to elucidate the membrane cake-layer fouling mechanisms due to bound extracellular polymeric substances (eEPS) in a submerged anaerobic membrane bioreactor (SAnMBR). This biofouling dynamic model explains the mechanisms such as attachment, consolidation and detachment of eEPS produced in the bioreactor on the membrane surface. The 4th order Runge-Kutta method was used to solve the model equations, and the parameters were estimated from simulated and experimental results. The key design parameters representing the behaviour of cake fouling dynamics were systematically investigated. Organic loading rate (OLR) was considered a controlling factor governing the mixed liquor suspended solids (MLSS), eEPS production, filtration resistance (Rt), and transmembrane pressure (TMP) variations in a SAnMBR. eEPS showed a proportional relation with OLR at subsequent MLSS variations. The consolidation of EPS increased the specific eEPS resistance (αs), influencing the cake resistance (Rc). The propensities of eEPS showed a positive correlation with Rt and TMP. The outcomes of the study also estimated a set of valuable design parameters which would be vital for applying in AnMBRs treating industrial wastewater.


Assuntos
Esgotos , Águas Residuárias , Reatores Biológicos , Filtração , Membranas Artificiais
5.
J Environ Manage ; 301: 113887, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34610559

RESUMO

Biodegradation of pyridine starts with two mono-oxygenation reactions, and 2-hydroxyl pyridine (2-HP) accumulates as pyridine is mono-oxygenated in the first reaction. The accumulation of 2-HP inhibits both initial reactions. Therefore, selective acceleration of the second mono-oxygenation reaction should significantly enhance pyridine transformation and mineralization. Activated-sludge biomass was separately acclimated with pyridine or 2-HP to produce pyridine- and 2-HP-acclimated biomasses. The pyridine-acclimated biomass was superior for pyridine biodegradation, but the 2-HP-acclimated biomass was superior for 2-HP biodegradation. As a consequence, the pyridine-acclimated biomass by itself achieved faster mono-oxygenation of pyridine to 2-HP, but 2-HP accumulated, which limited mineralization to 60%. In contrast, mineralization reached 90% when one-third of the pyridine-acclimated was replaced with 2-HP-acclimated biomass, because 2-HP did not accumulate during pyridine biodegradation. The lack of 2-HP accumulation relieved its inhibition: e.g., the pyridine removal rates, normalized to the mass of pyridine-acclimated biomass, increased from 0.52 to 0.57 mM0.5⋅h-1 when one-third of the pyridine-acclimated biomass was replaced by 2-HP-acclimated biomass. Phylogenetic analysis showed that microbiological communities of pyridine-acclimated biomass and 2-HP-acclimated biomass differed in important ways. On the one hand, the 2-HP-acclimated biomass was richer and dominated by a rare biosphere, or genera having <0.1% of total reads. On the other hand, the most-enriched genus in the pyridine-acclimated community (Methylibium) is associated with the first mono-oxygenation of pyridine, while enriched genera in the 2-HP-acclimated community (Sediminibacterium and Dokdonella) are associated with the second mono-oxygenation of pyridine.


Assuntos
Piridinas , Esgotos , Aceleração , Biomassa , Filogenia
6.
J Environ Manage ; 301: 113811, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34624579

RESUMO

BACKGROUND AND OBJECTIVES: Organic waste management in environmentally sustainable way is important not only to reduce the negative impacts on ecosystems but also valorizing the waste resources. Herein we evaluated the potential of wood ash (WA) and paper sludge (PS) wastes from a pulp and paper mill as potting media and their effects on the physicochemical properties of podzolic soil. METHODS: WA, PS and biochar (BC) was mixed in different combinations with a sandy loam podzolic soil. Potting media treatments included: T1-soil (negative control); T2-PromixTM (positive control); T3-50%soil+50%WA; T4-75%soil+25%WA; T5-50%soil+50%PS; T6-75%soil+25%PS; T7-75%soil+25%BC; T8-25%soil+50%WA+25%BC; T9-50%soil+25%WA+25%BC; T10-25%soil+50%PS+25%BC; T11-50%soil+25%PS+25%BC, T12- 25%soil+25%WA+25%PS+25%BC and replicated three times. RESULTS: Potting media treatments expressed significant (p < 0.00) effects on pH, bulk density, total porosity, field capacity, plant available water (PAW) and water retention curves. Potting media amended with WA showed high pH range (8-12) while PS amendments exhibited pH in range where most plant nutrients are available (6.5-7.5). Results depicted significantly lower bulk density, and increased total porosity and water holding capacity of potting media amended with WA and PS. BC addition further enhanced the water retention properties compared to combinations without BC. T6, T10 and T11 produced higher amounts of PAW with desired pH compared to T1 and T2. CONCLUSION: WA, PS and BC showed high potential for developing podzolic soil-based potting media, but their effects on plant growth and elemental uptake need to be investigated.


Assuntos
Poluentes do Solo , Solo , Carvão Vegetal , Ecossistema , Esgotos , Poluentes do Solo/análise
7.
J Environ Manage ; 301: 113877, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34626945

RESUMO

Finding suitable disposal sites for dredged marine sediments and incinerated sewage sludge ash (ISSA) is a challenge. Stabilisation/solidification (S/S) has become an increasingly popular remediation technology. This study sheds light on the possible beneficial use of ISSA together with traditional binders to stabilise/solidify marine sediments. The performance of the binders on S/S of sediment 1 (clean) and sediment 2 (contaminated) was also compared. The results showed that the use of ISSA as part of the binder was effective in promoting the strength of the sediment with a high initial moisture content due to ISSA porous and high water absorption characteristics. The sediments treated with 10% cement and 20% ISSA attained the highest strength. Also, cement hydration as well as pozzolanic reactions between ISSA and Ca(OH)2 made contributions to the strength development. This was supported by the microstructural analysis, in particular the porosity results. In terms of environmental impacts, two leaching tests (toxicity characteristic leaching procedure and synthetic precipitation leaching procedure) found that all the S/S treated sediment by 10% lime and 20% ISSA resulted in the lowest leachate concentrations under the on-site reuse scenario or under simulative acidic rainfall conditions. Therefore, recycling waste ISSA with lime can be used as an appealing binder to replace cement to stabilise/solidify dredged marine sediments for producing fill materials.


Assuntos
Reciclagem , Esgotos , Materiais de Construção , Sedimentos Geológicos
8.
J Environ Manage ; 301: 113914, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34628280

RESUMO

Humic acid (HA) is an important active compound formed during anaerobic digestion process, with a complex structure and dynamic electron transfer capacity (ETC). However, the mechanisms by which these macromolecular organic compounds dynamically interact with the microbial anaerobic digestion process at different operating temperatures are still unclear. In this study, the link between the evolution of the ETC of HAs and the microbial community under mesophilic and thermophilic conditions was investigated. The results showed an increasing trend in the ETC of HAs in both mesophilic (671-1479 µmol gHA-1) and thermophilic (774-1506 µmol gHA-1) anaerobic digestion (AD) until day 25. The ETC was positively correlated with the bacterial community of hydrolytic and acidogenic phases, but negatively correlated with the archaeal community of the methanogenic phase. Furthermore, the relationship between ETC and key enzyme activity was explored using a co-occurrence network analysis. HAs revealed a high potential to promote key enzyme activities during hydrolysis (amylase and protease) and acidification (acetate kinase, butyrate kinase, and phosphotransacetylase) while inhibiting the key enzyme activity in the methanogenic phase during the anaerobic digestion process. Moreover, HAs formed under thermophilic conditions had a greater influence on key enzyme activities than those formed under mesophilic conditions. This study advances our understanding of the mechanisms underlying the influence of HAs on anaerobic digestion performance.


Assuntos
Euryarchaeota , Substâncias Húmicas , Anaerobiose , Reatores Biológicos , Elétrons , Metano , Esgotos , Temperatura
9.
J Environ Manage ; 301: 113880, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34638042

RESUMO

The dairy industry produces vast quantities of dairy processing sludge (DPS), which can be processed further to develop second generation products such as struvite, biochars and ashes (collectively known as STRUBIAS). These bio-based fertilizers have heterogeneous nutrient and metal contents, resulting in a range of possible application rates. To avoid nutrient losses to water or bioaccumulation of metals in soil or crops, it is important that rates applied to land are safe and adhere to the maximum legal application rates similar to inorganic fertilizers. This study collected and analysed nutrient and metal content of all major DPS (n = 84) and DPS-derived STRUBIAS products (n = 10), and created an application calculator in MS Excel™ to provide guidance on maximum legal application rates for ryegrass and spring wheat across plant available phosphorus (P) deficient soil to P-excess soil. The sample analysis showed that raw DPS and DPS-derived STRUBIAS have high P contents ranging from 10.1 to 122 g kg-1. Nitrogen (N) in DPS was high, whereas N concentrations decreased in thermo-chemical STRUBIAS products (chars and ash) due to the high temperatures used in their formation. The heavy metal content of DPS and DPS-derived STRUBIAS was significantly lower than the EU imposed limits. Using the calculator, application rates of DPS and DPS-derived STRUBIAS materials (dry weight) ranged from 0 to 4.0 tonnes ha-1 y-1 for ryegrass and 0-4.5 tonnes ha-1 y-1 for spring wheat. The estimated heavy metal ingestion to soil annually by the application of the DPS and DPS-derived STRUBIAS products was lower than the EU guideline on soil metal accumulation. The calculator is adaptable for any bio-based fertilizer, soil and crop type, and future work should continue to characterise and incorporate new DPS and DPS-derived STRUBIAS products into the database presented in this paper. In addition, safe application rates pertaining to other regulated pollutants or emerging contaminants that may be identified in these products should be included. The fertilizer replacement value of these products, taken from long-term field studies, should be factored into application rates.


Assuntos
Agricultura , Metais Pesados , Fertilizantes/análise , Metais Pesados/análise , Fósforo , Esgotos , Solo
10.
Chemosphere ; 287(Pt 2): 132145, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34500330

RESUMO

Lake sediment and algal sludge with large output posed significant environmental risks. In this work, an idea of co-utilization of both solid wastes for the production of ceramsite (a sort of porous lightweight aggregates as building materials) was proposed and validated for the first time. The treatment process contained a dewatering step by a flocculation-pressure filtration method, and a sintered ceramsite preparation step. Effects of flocculant type and dosage on the dewatering performance were studied in the first step. An environmental-friendly amphoteric starch flocculant with a dosage of 12 mg/(g dried sample) was found to achieve the best dewatering performance. Effects of raw material mass ratio, sintering temperature and time in the second step were investigated. Under the optimal conditions (60 wt% of dewatered sediment; 20 wt% of dewatered algal sludge; 20 wt% of additives (fly ash: calcium oxide: kaolin = 2:1:2); sintering temperature: 1100 °C; time: 35 min), the obtained ceramsite met the Chinese National Standard as a qualified building material, with reliable environmental safety according to the leaching results for both heavy metals and microcystins. Both environmental and economic benefits of the proposed treatment were assessed. The process completely followed the rules of "reduction, harmlessness and resource utilization" for solid waste treatment and disposal; Meanwhile, the profit of the proposed ceramsite production could be more than 2.3 US dollar/m3. The co-utilization method in this work acted as a good example for the comprehensive management of solid wastes in water-rich areas.


Assuntos
Cianobactérias , Lagos , Cinza de Carvão , Misturas Complexas , Porosidade , Esgotos
11.
Chemosphere ; 287(Pt 2): 132191, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34509021

RESUMO

As the presence of emergent contaminants in wastewater, such as antibiotics, has become a threat for public health, the evaluation of strategies to treat them has been gaining importance. A critical example of this situation can be found in wastewaters coming from the pharmaceutical industry, where high concentrations of antibiotics are sometimes accompanied by high organic contents. Even the agroindustry can be affected by a similar problem when cattle infections are treated with antibiotics and part of the antibiotic-contaminated milk has to be wasted. With these situations in mind, in the present study we evaluated a progressive acclimation strategy for a granular sludge in a UASB reactor treating a high organic-content synthetic wastewater contaminated with azithromycin. In parallel, we tested a previously reported low-cost method for azithromycin determination by spectrophotometry, obtaining results comparable with liquid chromatography coupled to mass spectrometry. Although azithromycin has been reported as recalcitrant and resistant to biological degradation, the antibiotic was removed with efficiencies over 50% for wastewater with 10 mg L-1 of azithromycin and a COD of more than 4000 mgO2 L-1. Furthermore, efficiencies over 40% were achieved for wastewater with higher azithromycin concentrations (80 mg L-1) and a COD of 20,000 mgO2 L-1. A careful acclimation strategy permitted the partial removal of azithromycin from wastewater when treating concentrations comparable and higher than what would be expected for domestic and hospital wastewaters, even when its chemical oxygen demand is considerably higher than the average maximum of around 1000 mgO2 L-1.


Assuntos
Azitromicina , Águas Residuárias , Anaerobiose , Animais , Reatores Biológicos , Bovinos , Laboratórios , Esgotos , Eliminação de Resíduos Líquidos
12.
Chemosphere ; 287(Pt 2): 132151, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34517235

RESUMO

Anaerobic sludge was capable of producing anaerobic ammonium oxidation (anammox) cultures. However, the low activity of anammox bacteria in the seed sludge often led to a long time for stable anammox to initiate. The objective of this study was to investigate the influence of an extended reaction-phase time in the sequencing batch reactor (SBR) on the rapid startup of anaerobic ammonium oxidation (anammox) using anaerobic heterotrophic bacteria as the seed sludge. After the startup, suspended and attached bacteria in anammox were separately analyzed for comparison. The variations of nitrogen concentrations and shifts of the microbial community structures were studied. The results showed that anammox occurred after a long reaction-phase time in the SBR with the efficient removals of NH4+ (96.4%) and NO2- (99.8%). The effective NO2- treatment before anammox startup was attributable to inevitable denitrification or dissimilatory nitrate reduction (e.g., Denitratisoma). The occurrence of anammox was supported by the anammox stoichiometry, bacteria diversity variation, and principal component analysis. The overall nitrogen removal rate (NRR) and nitrogen removal efficiency (NRE) was 0.07 kg/m3-d and 92.8%, respectively. The relative molar quantities of NH4+ and NO2- removed as well as N2 and NO3- formed were 1(1):1.29(1.32):1.45(1.02):0.15(0.26), as the numbers in the parentheses represent the theoretical values. Denitratisoma and Desulfatiglans dominated in the seed sludge, whereas Candidatus_Jettenia abundances were significantly higher in anammox attached- (26.0%) and suspended-growth cultures (14.5%). Fifty-three genera were simultaneously identified in all samples, suggesting their importance in the startup of anammox from anaerobic sludge. Candidatus_Jettenia was observed to be more associated with the growth of anammox biofilm (the abundances were 26.0% and 14.5% in attached- and suspended-growth cultures, respectively) and supported the fine nitrogen removal performance in the attached-growth cultures.


Assuntos
Compostos de Amônio , Microbiota , Anaerobiose , Reatores Biológicos , Desnitrificação , Nitrogênio , Oxirredução , Esgotos
13.
Chemosphere ; 287(Pt 3): 132095, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34537456

RESUMO

This study investigated the mechanisms involved in CO2 sequestration under the sequence batch and semi-continuous operation using wollastonite in sludge anaerobic digestion. Wollastonite substantially elevated CH4 content in biogas and played a role in CO2 capture. It increased biogas yield of the glucose due to pH buffering effect but did not increase that of the hydrolysate from thermal alkali pretreated sludge. Under the semi-continuous operation, wollastonite improved the CO2 sequestration, but decreased the biogas yield from 166 to 24 mL/g soluble chemical oxygen demand, since seemingly wollastonite residues inhibited microbes in the sludge. However, the use of dialysis bags to wrap wollastonite offset the negative impact of the wollastonite residues in the sludge, thereby increased biogas yield. The present study is conducive to understanding the mechanisms involved in and proving the feasibility of the CO2 sequestration using wollastonite in sludge anaerobic digestion and its impacts on long-term operation. Consequently, the findings of the study provide key parameters and useful guidelines for scaling up and wollastonite application in anaerobic digestion of sewage sludge.


Assuntos
Dióxido de Carbono , Esgotos , Anaerobiose , Reatores Biológicos , Compostos de Cálcio , Diálise Renal , Silicatos
14.
Chemosphere ; 287(Pt 3): 132249, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34555584

RESUMO

Nano-zero-valent iron (nZVI), as a typical nano-material, has been recently used in wastewater treatment and combination with bioreactors. Using nZVI coupled denitrification system research the effect and influence of nZVI enhanced denitrification sludge on the degradation of toxic compounds and system performance. The nZVI coupled denitrification system showed better resistance to 2,6-DCP impact, and the concentrations of effluent NO2- and NO3- were below 2.0 mg/L. At the same time, the addition of nZVI enabled the denitrification system to quickly adapt to the toxic environment of 2,6-DCP within 15 days, and the degradation efficiency of 2,6-DCP reached 99.9%. The released SMP reduced after nZVI coupled with denitrification sludge in 2,6-DCP environment, which could improve the effluent water quality. Nuclear magnetic resonance spectroscopy showed that the addition of nZVI would change the structure of EPS in denitrification sludge. After 90 days of operation, the dominant bacteria in the denitrifying sludge have undergone great changes. Moreover, Thauera was responsible as the dominant bacteria for degrading 2,6-DCP in the denitrification system. The increased in the proportion of functional bacteria with nitrate_reduction, nitrogen_respiration, nitrate_respiration and nitrite_respiration in the presence of NZVI further reveals the mechanism of enhanced denitrification.


Assuntos
Desnitrificação , Nitratos , Clorofenóis , Ferro , Esgotos
15.
Chemosphere ; 287(Pt 3): 132322, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34560493

RESUMO

A novel high-concentration powder bio-carrier (HPB) process was developed for the high-load treatment of low-strength municipal wastewater with low carbon/nitrogen (C/N) ratio (∼3). The powder carrier facilitated the rapid micro-granulation of sludge within 20 days and the average particle size increased rapidly from 47 µm to 210 µm. Accordingly, the concentration of mixed liquid volatile suspended solids (MLVSS) increased from 1.8 g/L to 4.3 g/L, which enabled the HPB process to maintain a short hydraulic retention time (HRT) of 3.6 h. Correspondingly, the high volumetric load of 0.4-1.3 kg chemical oxygen demand (COD)/(m3∙d) and 0.12-0.24 kg total nitrogen (TN)/(m3∙d) could be achieved and twice higher than those of conventional activated sludge process, e.g., anaerobic/anoxic/oxic process. The carrier-induced sludge granulation also significantly optimized the microbial structure, and the high-throughput sequencing revealed the increasing abundances of denitrifying bacteria and anammox bacteria, which was consistent with the nitrogen removal efficiency rising from 44.6% to 77.4%. Accordingly, the enhanced nitrogen removal could be achieved with TN of effluent steadily below 5 mg/L. Especially, the mass balance analysis on carbon and nitrogen further indicated the advantage of newly developed HPB process in carbon source saving for nitrogen removal. All the results are believed to suggest a promising strategy for the highly efficient treatment of low-strength municipal wastewater.


Assuntos
Esgotos , Águas Residuárias , Reatores Biológicos , Carbono , Desnitrificação , Nitrogênio , Eliminação de Resíduos Líquidos
16.
Chemosphere ; 287(Pt 3): 132213, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34560494

RESUMO

The effects of different surfactants (rhamnolipid, trehalolipid and citrate) on phosphorus (P) release and acidogenic fermentation of waste activated sludge (WAS) containing different aluminium phosphate forms (AlPO4, Al(PO3)3) were investigated. Results showed that rhamnolipid was the most effective surfactant to release P from aluminum phosphates (AlPs)-rich sludge. Al(PO3)3 was easier to release P than AlPO4 in WAS due to their different crystal structures. Different surfactants promoted the production of different types of protein. The addition of rhamnolipid was conducive to produce propionate from WAS, while trehalolipid and citrate increased the production of n-butyrate and acetate, respectively. Citrobacter played an important role in producing phosphatase continuously for P release with rhamnolipid addition. Predictive functional profiling indicates that rhamnolipid greatly facilitated adenosine triphosphate (ATP)-binding cassette transporter and quorum sensing. These important discoveries help to enrich P recovery paths from sludge produced with Al-based coagulants in wastewater treatment plants.


Assuntos
Fósforo , Esgotos , Compostos de Alumínio , Fermentação , Fosfatos , Tensoativos , Eliminação de Resíduos Líquidos
17.
Chemosphere ; 287(Pt 3): 132181, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34583297

RESUMO

The high toxicity of Cr-Ca compounds generated during the heat treatment of solid waste will heavily threat the environment. In this work, a kind of Ca-rich river sludge which is bound with Ca and heavy metals was combusted with kaolin under 900 °C for 3 h in a muffle to study the transformation of Cr. The effects of kaolin on Cr transformation were investigated through sequential extraction, the risk assessment of heavy metals, and constant pH leaching test, also combined with crystal phase analysis of Ca-Al-Si minerals. The experimental results showed that the formation of Ca10(SiO4)3(SO4)3Cl2 was inhibited by the addition of 10% (mass fraction) kaolin and the released Cl promoted the evaporation of target elements in priority while 30% kaolin addition further inhibited the solidification of Cr. Furthermore, the effect of NaCl and CaCO3 on the Cr solidification by kaolin were also explored by leaching procedure or XRD analysis of calcination products of their mixtures. It should be noticed that the addition of kaolin in Cr2O3-CaCO3 mixture will directly react with CaCrO4 and fixed the generated Cr2O3 into internal layered structure, preventing its re-oxidization by the free CaO. This work aims to help illustrate the Cr transformation with existence of Ca during sintering of Ca-rich solid wastes and reduce the Cr contamination in future.


Assuntos
Metais Pesados , Resíduos Sólidos , Caulim , Metais Pesados/análise , Esgotos
18.
Environ Pollut ; 292(Pt A): 118267, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34601036

RESUMO

Distillery sludge is a major source of aquatic pollution, but little is known about their microbial community and their association with the organic and metal pollutants. Sugarcane molasses-based distillery is an important industry in India, although the waste is usually treated prior to disposal, the treatment is often inadequate. The adverse effects of the organic and metal pollutants in sugarcane molasses-based distillery sludge on the microbial biodiversity and abundance in the disposal site have not been elucidated. This study aims to address this gap of knowledge. Samples were collected from the discharge point, 1 and 2 km downstream (D1, D2, and D3, respectively) of a sugarcane distillery in Uttar Pradesh, India, and their physico-chemical properties characterised. Using QIIME, taxonomic assignment for the V3 and V4 hypervariable regions of 16 S rRNA was performed. The phyla Proteobacteria (28-39%), Firmicutes (20-28%), Bacteriodetes (9-10%), Actinobacteria (5-10%), Tenericutes (1-9%) and Patescibacteria (2%) were the predominant bacteria in all three sites. Euryechaeota, were detected in sites D1 and D2 (1-2%) but absent in D3. Spirochaetes (5%), Sinergistetes (2%) and Cloacimonetes (1%) were only detected in samples from site D1. Shannon, Simpson, Chao1, and Observed-species indices indicated that site D1 (10.18, 0.0013, 36706.55 and 45653.84, respectively) has higher bacterial diversity and richness than D2 (6.66, 0.0001, 25987.71 and 49655.89, respectively) and D3 (8.31, 0.002, 30345.53 and 30654.88, respectively), suggesting the organic and metal pollutants provided the stressors to favour the survival of microbial community that can biodegrade and detoxify them in the distillery sludge. This study confirmed that the treatment of the distillery waste was not sufficiently effective and provided new metagenomic information on its impact on the surrounding microbial community. It also offered new insights into potential bioremediation candidates.


Assuntos
Poluentes Ambientais , Microbiota , Saccharum , Melaço , Esgotos , Eliminação de Resíduos Líquidos , Águas Residuárias
19.
Environ Pollut ; 292(Pt A): 118307, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34626713

RESUMO

Municipal sewage treatment plants (STPs) have been regarded as an important source of organic contaminants in aquatic environment. To assess the impact of STPs on occurrence and toxicity of STP-associated contaminants in receiving waterways, a novel passive sampler modified from polar organic chemical integrative sampler (m-POCIS) was deployed at the inlet and outlet of a STP and several upstream and downstream sites along a river receiving STP effluent in Guangzhou, China. Eighty-seven contaminants were analyzed in m-POCIS extracts, along with toxicity evaluation using zebrafish embryos. Polycyclic musks were the predominant contaminants in both STP and urban waterways, and antibiotics and current-use pesticides (e.g., neonicotinoids, fiproles) were also ubiquitous. The m-POCIS extracts from downstream sites caused significant deformity in embryos, yet the toxicity could not be explained by the measured contaminants, implying the presence of nontarget stressors. Sewage treatment process substantially reduced embryo deformity, chemical oxygen demand, and contamination levels of some contaminants; however, concentrations of neonicotinoids and fiproles increased after STP treatment, possibly due to the release of chemicals from perturbed sludge. Source identification showed that most of the contaminants found in urban waterways were originated from nonpoint runoff, while cosmetics factories and hospitals were likely point sources for musks and antibiotics, respectively. Although the observed embryo toxicity could not be well explained by target contaminants, the present study showed a promising future of using passive samplers to evaluate chemical occurrence and aquatic toxicity concurrently. Zebrafish embryo toxicity significantly decreased after sewage treatment, but higher toxicity was observed for downstream samples, demonstrating that urban runoff may produce detrimental effects to aquatic life, particularly in rainy season. These results highlight the relevance of monitoring nonpoint source pollution along with boosting municipal sewage treatment infrastructure.


Assuntos
Esgotos , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Compostos Orgânicos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
20.
Sci Total Environ ; 803: 150023, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34500268

RESUMO

Application of organic wastes as soil fertilizers represents an important route of agricultural soil contamination by antibiotics such as sulfamethoxazole (SMX). Soil contamination may be influenced by the storage time of organic wastes before soil spreading. The objective of this work was to study the fate of SMX in two organic wastes, a co-compost of green waste and sewage sludge and a bovine manure, which were stored between 0 and 28 days, then incorporated in an agricultural soil that has never received organic waste and monitored for 28 days under laboratory conditions. Organic wastes were spiked with 14C-labelled SMX at two concentrations (4.77 and 48.03 mg kg-1 dry organic waste). The fate of SMX in organic wastes and soil-organic waste mixtures was monitored through the distribution of radioactivity in the mineralised, available (2-hydroxypropyl-ß-cyclodextrin extracts), extractable (acetonitrile extracts) and non-extractable fractions. SMX dissipation in organic wastes, although partial, was due to i) incomplete degradation, which led to the formation of metabolites detected by high performance liquid chromatography, ii) weak adsorption and iii) formation of non-extractable residues. Such processes varied with the organic wastes, the manure promoting non-extractable residues, and the compost leading to an increase in extractable and non-extractable residues. Short storage does not lead to complete SMX elimination; thus, environmental contamination may occur after incorporating organic wastes into soil. After addition of organic wastes to the soil, SMX residues in the available fraction decreased quickly and were transferred to the extractable and mostly non-extractable fractions. The fate of SMX in the soil also depended on the organic wastes and on the prior storage time for manure. However the fate of SMX in the organic wastes and soil-organic waste mixtures was independent on the initial spiked concentration.


Assuntos
Compostagem , Poluentes do Solo , Animais , Bovinos , Esterco , Esgotos , Solo , Sulfametoxazol
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