Humic-like Materials Research Articles

Characterization of dissolved organic matter in landfill leachate during the combined treatment process of air stripping, Fenton, SBR and coagulation

A combined treatment process of air stripping+Fenton+sequencing batch reactor (SBR)+ coagulation was performed to remove the pollutants in landfill leachate. Molecular weight (MW) distribution and fractions of dissolved organic matter (DOM) were discussed to study the characteristics. The experiment showed that the removal rate of chemical oxygen demand (COD), five day biological oxygen demand (BOD5) and ammonia nitrogen (NH3N) by the combined process were 92.8%, 87.8% and 98.0%, respectively. Humic acid (HA) and fulvic acid (FA) were the main fractions in raw leachate with 81.8% of the total COD concentration, while hydrophilic organic matter (HyI) was the dominant fraction in the final effluent of the combined process with 63.5% of the total COD concentration. After the combined treatment process, the removal rate of DOM and fractions HA, FA, HyI were 91.9%, 97.1%, 95.8% and 71.7%, respectively. Organic matters of MW<2k and MW>100k were removed with 90.5% and 97.9% COD concentration after the treatment. The ultraviolet–visible spectra (UV–vis), Fourier transform infrared spectra (FTIR) and three-dimensional excitation-emission matrices spectra (EEMs) indicated that benzene materials and phenol compounds were preferentially removed in air stripping. High MW matters, aromatic rings, conjugated moieties and some functional groups were mainly removed by Fenton. While smallMW fractions, carboxylic acids, alcohols and protein-like materials were preferentially biodegraded via SBR. Fulvic-like and humic-like materials were mainly destroyed via Fenton oxidation and coagulation.

Applying fluorescence spectroscopy and multivariable analysis to characterize structural composition of dissolved organic matter and its correlation with water quality in an urban river

Excitation–emission matrix fluorescence spectroscopy combined with multivariable analysis was employed to discriminate structural component of dissolved organic matter (DOM) in Xihe River, an urban river, located in western Shenyang City of China, and to reveal its correlation with water quality. Eight water samples were collected along the river across the centralized wastewater-discharge region and the dispersed wastewater-discharge region. Water quality had deeply deteriorated in the river. Based on DOM fluorescence spectroscopic properties, DOM was composed of tyrosine-like, tryptophan-like, soluble microbial by-product-like, fulvic-like and humic-like materials, among which protein-like material was dominant in the DOM fractions. The DOM in the centralized wastewater-discharge region had a lower level of aromaticity than that in the dispersed wastewater-discharge region, and its humification degree was lower than that in the latter too. Key factors for the trophic state contained NH4-N, DO, DOC, TP, Φ 2,n and Φ 4,n by multivariable analysis. DOM was mainly derived from treated and untreated industrial wastewater with weak biodegradability.

Impact of spring flooding on DOM characterization in a small watershed of the Hun River, China

Potential water pollution derived from melting snow is a growing concern to watershed management in northern climates. For most small watersheds in the Hun River Basin, substantial portions of the annual load of pollutants such as organic matter, ammonia, phosphorus and metals come from snowmelt and early spring runoff. Thus, the annual spring flood is a real threat to the trophic state and water quality of Hun River. By three-dimensional fluorescence technology, the composition and characteristics of dissolved organic matter (DOM) in early spring runoff of a small watershed (the Baitapu River) were analyzed, and the correlation with land use was investigated. The result showed that compared with NH3-N and TP, DOM was not the major contributor to water quality deterioration in spring flooding, but its composition still presented significant differences. Compared with that in medium flow period, the abundance of a soluble microbial byproduct-like material in the spring-flood period decreased from 28.6 to 15.8 %, while those of tyrosine-like material and humic-like material increased from 36.0 and 1.8 % to 44.4 and 10.7 %, respectively. DOM in spring flooding had a relatively higher aromaticity degree, a greater humification level, and a larger molecular weight. Meanwhile, DOM from urban areas contained more tyrosine-like material. For the Baitapu River, urban areas were the major DOM source in both the medium flow period (from dispersed point sources) and the spring flood period (from a wastewater treatment plant). Therefore, DOM composition can be used as an effective indicator for tracking pollution sources.

Uncomposted Sheep and Cow Manures as a Source of Commercial Humic Amendments: An Exploratory Study

Liquid humic amendments are widely used in many countries as an enhancer of crop production (particularly root growth). While leonardite is the main substrate for obtaining these products, there is growing concern about obtaining them from plant-derived residual materials, rich in lignin and polyphenolics, thus making possible a residue valorization. Composting is a necessary step for converting these residues into a source of humic substances. In arid countries, obtaining humic products from sources other than leonardite faces two main challenges: (i) often such countries are devoid of forested areas or tree crops capable of supplying lignin-rich residues in large amounts and (ii) water is scarce (or very expensive if obtained by desalination) and therefore composting on an industrial scale is very difficult. Thus it is essential to find alternative sources capable of yielding humic or humic-like compounds without any previous composting. Here we present the main results obtained using sheep and cow manure, two materials widely available in the Kingdom of Saudi Arabia (KSA). Both were extracted using potassium hydroxide (KOH) at a variety of concentrations (from 0.25 to 2 M), times (from 20 to 120 min), temperatures (from 100 to 150 °C), and pressures. Sheep manure, much easier to extract than cow manure, appears the more promising as a source of commercial humic amendments. No lengthy extraction times are needed to obtain alkaline extracts; 20 min yields only slightly less humic-like matter than 2 h. The relative abundance of humic-like substances in the extract tends to decrease with time, but some optical indicators of humification (E4/E6 ratio, absorption at 280 nm, ratios of absorption at 253/203 and 253/220 nm) tend to increase. Polysaccharides, the dominant form of organic matter in the original manure, strongly resist alkaline extraction: their prior hydrolysis may be necessary to increase the yields of humic-like matter from the studied manures.

Comparison of organic matter composition in agricultural versus forest affected headwaters with special emphasis on organic nitrogen.

Agricultural management practices promote organic matter (OM) turnover and thus alter both the processing of dissolved organic matter (DOM) in soils and presumably also the export of DOM to headwater streams, which intimately connect the terrestrial with the aquatic environment. Size-exclusion chromatography, in combination with absorbance and emission matrix fluorometry, was applied to assess how agricultural land use alters the amount and composition of DOM, as well as dissolved organic nitrogen (DON) forms in headwater streams, including temporal variations, in a temperate region of NE Germany. By comparing six agriculturally and six forest-impacted headwater streams, we demonstrated that agriculture promotes increased DOC and DON concentrations, entailing an even more pronounced effect on DON. The major part of DOC and DON in agricultural and forest reference streams is exported in the form of humic-like material with high molecular weight, which indicates terrestrial, i.e., allochthonous sources. As an obvious difference in agricultural streams, the contribution of DOC and particularly DON occurring in the form of nonhumic high-molecular-weight, presumably proteinous material is clearly elevated. Altogether, DOM in agricultural headwaters is mainly complex-soil-derived and aromatic material with a low C:N ratio, which is more microbial processed than its counterpart from forest reference catchments. Our results emphasize the importance of agricultural land use on DOM loss from soils and identify agricultural soils as important DOC and particularly DON sources to headwater streams.

Contributions of spatial, temporal, and treatment impacts on natural organic matter character using fluorescence-based measures

The potential application of fluorescence spectroscopy for monitoring of organic matter concentration and character at four water treatment facilities was investigated. Results are presented showing impacts on natural organic matter (NOM) due to intake location on the same water body and from individual unit processes including ozonation, granular-activated carbon filtration, and coagulation/flocculation. For validation and comparison of fluorescence methods, organic matter was quantified and characterized using liquid chromatography-organic carbon detection (LC-OCD). Principal component analysis (PCA) and parallel factors analysis were used for dimensionality reduction and to represent individual organic components observed through fluorescence excitation-emission matrices. Fluorescence results generally agreed with LC-OCD characterization, indicating that complete treatment reduced organic concentrations and preferential removal of humic-like material was associated with coagulation/flocculation. PCA results indicated higher concentrations of humic-like material at the Island water treatment plant intake that was not well reduced by inline polyaluminum chloride coagulation and direct filtration. Through fluorescence spectroscopy, ozonation increased Rayleigh scattering, which is correlated to small colloidal/particulate concentrations. Full-scale results from four water treatment plants presented demonstrate that fluorescence methods can characterize NOM, providing similar identification of trends to LC-OCD, with possible online application and use in real-time water treatment process control.

Effects of molecular weight-dependent physicochemical heterogeneity of natural organic matter on the aggregation of fullerene nanoparticles in mono- and di-valent electrolyte solutions

Given the wide presence of heterogeneous natural organic matter (NOM) and metal ions (Na+/Ca2+/Mg2+), as well as their significant role in governing nanoparticle stability in aqueous environments, it is of great importance to understand how the molecular weight (MW)-dependent physicochemical properties of NOM impact fundamental transportation processes like the aggregation of engineered nanoparticles (ENPs) in the presence of Na+/Ca2+/Mg2+. Here, we report on the aggregation behavior of a model ENP, fullerene nanoparticles (nC60) in the presence of five MW fractions of Suwannee River NOM (Mf-SRNOMs, separated by ultrafiltration techniques) and three electrolytes (NaCl, CaCl2 and MgCl2). We found that in all NaCl treatments and low concentration CaCl2/MgCl2 treatments, the enhancement of nC60 stability positively correlated with the MW of Mf-SRNOMs. Whereas, the stability efficiency of identical Mf-SRNOM in different electrolytes followed an order of NaCl > MgCl2 > CaCl2, and the enhanced attachment of nC60-SRNOM associations was observed in high MW Mf-SRNOM (SRNOM>100 kD and SRNOM 30–100 kD) at high concentration CaCl2/MgCl2. Our results indicate that although the high MW NOM with large humic-like material is the key component for stabilizing nC60 in monovalent electrolyte, it could play a reversed role in promoting the attachment of nC60, especially in long term aggregations and at high concentrations of divalent cations. Therefore, a detailed understanding of the effects of heterogeneous NOM on the aggregation of ENPs should be highly valued, and properly assessed against different cation species and concentrations.

Using fluorescence spectroscopy coupled with chemometric analysis to investigate the origin, composition, and dynamics of dissolved organic matter in leachate-polluted groundwater.

Groundwater was collected in 2011 and 2012, and fluorescence spectroscopy coupled with chemometric analysis was employed to investigate the composition, origin, and dynamics of dissolved organic matter (DOM) in the groundwater. The results showed that the groundwater DOM comprised protein-, fulvic-, and humic-like substances, and the protein-like component originated predominantly from microbial production. The groundwater pollution by landfill leachate enhanced microbial activity and thereby increased microbial by-product-like material such as protein-like component in the groundwater. Excitation-emission matrix fluorescence spectra combined with parallel factor analysis showed that the protein-like matter content increased from 2011 to 2012 in the groundwater, whereas the fulvic- and humic-like matter concentration exhibited no significant changes. In addition, synchronous-scan fluorescence spectra coupled with two-dimensional correlation analysis showed that the change of the fulvic- and humic-like matter was faster than that of the protein-like substances, as the groundwater flowed from upstream to downstream in 2011, but slower than that of the protein-like substance in 2012 due to the enhancement of microbial activity. Fluorescence spectroscopy combined with chemometric analysis can investigate groundwater pollution characteristics and monitor DOM dynamics in groundwater.

Production and degradation of fluorescent dissolved organic matter in surface waters of the eastern north Atlantic ocean

The distribution and fate of coloured dissolved organic matter (CDOM) in the epipelagic Eastern North Atlantic was investigated during a cruise in the summer 2009 by combining field observations and culture experiments. Dissolved organic carbon (DOC) and nitrogen (DON), the absorption spectra of CDOM and the fluorescence intensity of proteins (Ex/Em 280/320nm; F(280/320)) and marine humic-like substances (F(320/410)) were measured in the upper 200m. DOC and DON showed higher concentrations in the top 20m than below, and DOC increased southwards, while DON decreased. F(280/320) and F(320/410) showed maxima near the deep chlorophyll maximum (at about 50m), suggesting that these fluorophores were linked to phytoplankton production and the metabolism of the associated microbial community. The coloured and fluorescent fractions of DOM showed low levels south of the Azores Front, at about 35°N, likely due to the accumulated photobleaching of the waters transported eastwards by the Azores current into the study area (at 20°W). Twelve culture experiments were also conducted with surface water (5m) to assess the impact of microbial degradation processes on the bulk, coloured and fluorescent fractions of DOM. After 72h of incubation in the darkness, 14±9% (average±SD) of the initial DON was consumed at an average rate of 0.24±0.14µmol l−1 d–1 and the protein-like fluorescence decayed by 29±9% at a net rate of 0.06±0.03 QSU d–1. These rates were significantly lower south of the Azores front, suggesting that DOM in this region was of a more recalcitrant nature. Conversely, the marine humic-like fluorescence increased at a net rate of 0.013±0.003 QSU d–1. The close linear relationship of DON uptake with F(280/320) consumption (R2= 0.91, p <0.0001, n=12) and F(320/410) production (R2= 0.52, p <0.008, n=12) that we found during these incubation experiments suggest that the protein-like fluorescence can be used as a proxy for the dynamics of the labile DON pool and that marine humic-like materials can be produced as a by-product of microbial DOM degradation.

Insights into the composition and sources of rural, urban and roadside carbonaceous PM₁₀.

Insights into the nature and sources of the urban and roadside increments in carbonaceous PM10 are gained from bulk chemical analyses on daily filter samples collected at a roadside, urban background and rural site in Edinburgh, UK (not all sampling contemporaneous). The concentrations of PM10 water-soluble organic matter (WSOM) at the three sites were similar, and (where measured concurrently) strongly correlated, indicating a uniform background source, in contrast to the black carbon component (quantified by filter optical reflectance) whose average concentrations at urban background and roadside were, respectively, about 3 and 7 times greater than at the rural site, indicating local urban sources. BC was not a major component of PM10 but was a major component of the urban and roadside PM10 increments (∼50% and ∼60% respectively). The roadside WSOM had greater hydrophobicity than the urban background WSOM. UV-vis spectra indicated increased prevalence of unsaturated bonds and conjugation in urban background WSOM in winter compared with summer. This is consistent with both summertime photochemical production of particle OM and maritime primary aliphatic WSOM. Raman microscopy of a small subset of samples indicated carbon functionality ranged between diesel-like material and more complex humic-like material. Results overall indicate the presence of a background functionalized carbonaceous material, with local BC sources superimposed.

Towards understanding the stabilization process in vermicomposting using PARAFAC analysis of fluorescence spectra

In this study, fluorescence excitation–emission matrix (EEM) combined with parallel factor analysis (PARAFAC) was employed to trace the behavior of water extractable organic matter and assess the stabilization process during vermicomposting of sewage sludge and cattle dung. Experiments using different mixing ratios of sewage sludge and cattle dung were conducted using Eisenia fetida. The results showed that vermicomposting reduced the DOC, DOC/DON ratio and ammonia, while increased the nitrate content. A three-component model containing two humic-like materials (components 1 and 2) and a protein-like material (component 3) was successfully developed using PARAFAC analysis. Moreover, the initial waste composition had a significant effect on the distribution of each component and the addition of cattle dung improved the stability of sewage sludge in vermicomposting. The PARAFAC results also indicated that protein-like materials were degraded and humic acid-like compounds were evolved during vermicomposting. Pearson correlation analysis showed that components 2 and 3 are more suitable to assess vermicompost maturity than component 1. In all, EEM–PARAFAC can be used to track organic transformation and assess biological stability during the vermicomposting process.

Watershed Glacier Coverage Influences Dissolved Organic Matter Biogeochemistry in Coastal Watersheds of Southeast Alaska

The Coast Mountains of southeast Alaska are currently experiencing some of the highest rates of glacier volume loss on Earth, with unknown implications for proglacial stream biogeochemistry. We analyzed streamwater for δ18O and dissolved organic matter (DOM) biogeochemistry (concentration, δ13C-dissolved organic carbon (DOC), and fluorescence characterization) during the 2012 glacial runoff season from three coastal watersheds in southeast Alaska that ranged in glacier coverage from 0 to 49% and a glacier outflow stream. Our goal was to assess how DOM biogeochemistry may change as receding glaciers are replaced by forests and glaciers contribute less meltwater to streamflow. Discharge and streamwater δ18O varied seasonally reflecting varying contributions of rainfall and snow/icemelt to streamflow over the runoff season. Mean DOC concentrations were lowest in the glacial outflow and highest in the non-glacial stream reflecting an increasing contribution of vascular plant-derived carbon with decreasing watershed glaciation. Fluorescence and δ13C-DOC signatures indicated that DOM shifted from vascular plant-derived, humic-like material in the non-glacial stream toward more δ13C-DOC enriched, glacier-derived DOM in the glacial outflow. Streamwater δ18O was significantly correlated to DOC concentration, δ13C-DOC, and protein-like fluorescence of streamwater DOM (all P < 0.05), demonstrating that changes in the source of streamwater across the glacial watershed continuum have important implications for the amount and quality of stream DOM export. Overall, our findings show that continued glacial recession and subsequent changes in glacial runoff could substantially influence the biogeochemistry of coastal temperature watersheds by altering the timing, magnitude, and chemical signature of DOM delivered to streams.

Influence of the composition and removal characteristics of organic matter on heavy metal distribution in compost leachates

Compost leachates were collected to investigate the influence of the composition and removal of volatile fatty acids (VFAs), humic-like substances (HSs), and dissolved organic nitrogen (DON) on heavy metal distribution during the leachate treatment process. The results showed that acetic and propionic acids accounted for 81.3 to 93.84% of VFAs, and that these acids were removed by the anaerobic-aerobic process. Humic- and fulvic-like substances were detected by excitation-emission matrix spectroscopy coupled with parallel factor analysis, and their content significantly decreased after the anaerobic and membrane treatments. DON in compost leachates ranged from 26.53 mg L(-1) to 919.46 mg L(-1), comprised of dissolved free amino acids and the protein-like matter bound to humic- and fulvic-like substances, and was removed by the aerobic process. Correlation analysis showed that Mn, Ni, and Pb were bound to VFAs and protein-, fulvic-, and humic-like substances in the leachates. Co was primarily bound to fulvic- and humic-like matter and inorganic sulfurs, whereas Cu, Zn, and Cd interacted with inorganic sulfur.

Composition of dissolved organic matter along an Atlantic Meridional Transect from fluorescence spectroscopy and Parallel Factor Analysis

Absorption spectra and induced fluorescence excitation emission matrices of colored dissolved organic matter were measured in water samples collected along the Atlantic Meridional Transect in different bio-geographic provinces of the Atlantic Ocean from October to November 2010. The highest values of CDOM absorption coefficient at 305nm (aCDOM(305)), were recorded at the continental margins of the English Channel and Patagonian Shelf. The lowest values of aCDOM(305) were observed in the mixed layer of both North and South Atlantic subtropical oligotrophic gyres. The DOM composition was assessed using fluorescence spectroscopy, Excitation Emission Matrix spectra (EEMs) and the Parallel Factor Analysis (PARAFAC) model in addition to spectral indices calculated from CDOM absorption spectrum and EEMs. Six different components were identified in the EEMs by PARAFAC: Two components were similar to the humic-like fraction of DOM, associated with basin scale microbial mineralization processes. These components represent allochthonous DOM in the biogeographic provinces studied. One component of marine humic-like material of autochthonous origin was associated with DOM production from marine phytoplankton. Three components were associated with protein-like DOM. Two protein-like components had the spectral characteristics of pure tryptophan and tyrosine. There was a significant difference in DOM composition both between bio-geographical provinces and above and below the mixed layer. In the mixed layer in all provinces, except the waters of the Western European Shelf, the DOM was dominated by protein-like components. At the Western European Shelf, it was dominated by humic-like components. Fluorescence intensities of humic-like components were high at the Patagonian Shelf, but were up to 40% lower compared to northern hemisphere shelf waters. Humic-like components made a significant contribution to the DOM composition of the upper mesopelagic layer in all provinces, with the highest values at the Equatorial Upwelling Zone. There was a significant inverse relationship between humic-like components and salinity and temperature and a positive relationship with Apparent Oxygen Utilization. The humification index (HIX) was linearly correlated with the intensity of the humic-like DOM components. These trends suggest that the humic-like components are in dynamic equilibrium between likely microbial production in the deep ocean and photochemical degradation in the mixed layer.

Revealing Sources and Distribution Changes of Dissolved Organic Matter (DOM) in Pore Water of Sediment from the Yangtze Estuary

Dissolved organic matter (DOM) in sediment pore waters from Yangtze estuary of China based on abundance, UV absorbance, molecular weight distribution and fluorescence were investigated using a combination of various parameters of DOM as well as 3D fluorescence excitation emission matrix spectra (F-EEMS) with the parallel factor and principal component analysis (PARAFAC-PCA). The results indicated that DOM in pore water of Yangtze estuary was very variable which mainly composed of low aromaticity and molecular weight materials. Three humic-like substances (C1, C2, C4) and one protein-like substance (C3) were identified by PARAFAC model. C1, C2 and C4 exhibited same trends and were very similar. The separation of samples on both axes of the PCA showed the difference in DOM properties. C1, C2 and C4 concurrently showed higher positive factor 1 loadings, while C3 showed highly positive factor 2 loadings. The PCA analysis showed a combination contribution of microbial DOM signal and terrestrial DOM signal in the Yangtze estuary. Higher and more variable DOM abundance, aromaticity and molecular weight of surface sediment pore water DOM can be found in the southern nearshore than the other regions primarily due to the influence of frequent and intensive human activities and tributaries inflow in this area. The DOM abundance, aromaticity, molecular weight and fluorescence intensity in core of different depth were relative constant and increased gradually with depth. DOM in core was mainly composed of humic-like material, which was due to higher release of the sedimentary organic material into the porewater during early diagenesis.

Foulant analysis of a reverse osmosis membrane used pretreated seawater

This study focused on the characterization of organic and biological foulants on reverse osmosis (RO) membrane and fouled RO membrane characterization with seawater pretreated by submerged membrane hybrid systems (SMHSs). New low pressure membrane based pretreatments namely submerged membrane coagulation hybrid system (SMCHS) and submerged membrane coagulation-adsorption hybrid system (SMCAHS) were investigated. Organic foulants on RO membrane were characterized in terms of molecular weight distribution (MWD), fluorescence and extracellular polymeric substance (EPS) analyses. The organic foulants were mainly composed of high molecular weight matters representing biopolymers in the foulants. The fluorescence excitation–emission matrix (F-EEM) analysis showed that protein-like materials were dominant with samples pretreated by SMHSs. Humic-like materials which have lower aromaticity were also present in the foulant. Biological foulants were investigated in terms of total direct cell (TDC) count, cell viability and biomass activity (adenosine tri-phosphate; ATP). Biological fouling was found to be reduced by organic removal with SMHSs. The fouled membranes were characterized using environmental scanning electron microscopy coupled with energy dispersive spectroscopy, attenuated total reflection-Fourier transform infrared spectrometry, zeta-potential measurement, atomic force microscopy, and contact angle measurement.

A detailed organic matter characterization of pretreated seawater using low pressure microfiltration hybrid systems

In this study, two different submerged membrane hybrid systems (SMHSs) namely (i) submerged membrane coagulation hybrid system (SMCHS) and (ii) submerged membrane coagulation-adsorption hybrid system (SMCAHS) were investigated as pretreatment options for seawater reverse osmosis. Organic matters in seawater before and after pretreatment were characterized in terms of XAD fractionation, molecular weight distribution (MWD) and fluorescence. A detailed study on the seawater organic matter (SWOM) structure was made through 1H-nuclear magnetic resonance (1H NMR), pyrolysis-gas chromatography–mass spectrometry (Py-GC/MS) and liquid chromatography–mass spectrometry-ion trap-time of fright (LC/MS-IT-TOF). The seawater investigated in this study is mainly composed of hydrophilic matter (57±3.2%). SMHSs removed a significant amount of organic matter. The EEM fluorescence showed a removal of humic-like materials by SMHSs. In addition, humic-like materials relative to protein-like compounds were reduced significantly but the aromaticity of humic-like materials increased. After pretreatment by SMHSs, humics and biopolymers of over 900Da. were found to be reduced and their structure associated with element composition was also changed. The transformation of the SWOM structure after SMHSs pretreatment may have been due to hydrolyzation or oxidization of the organic compounds such as humics and biopolymers resulting in poly-conjugation to aromatic compounds. SMHSs were effective in improving the RO performance leading to higher RO permeate flux and lower permeate flux decline. The pretreatment reduced the amount of foulants on the RO membrane.

Elemental and spectroscopic methods with chemometric analysis for characterizing composition and transformation of dissolved organic matter during chicken manure composting

Dissolved organic matter was extracted from chicken manure after 1, 8, 16, 28 and 40 days of composting and characterized by combining elemental and spectroscopic methods with chemometric analysis to investigate the evolution of composting materials. The elemental and spectroscopic analysis results showed that the composting process was characterized by the biodegradation of aliphatics, polysaccharide and proteins, as well as by the synthesis of aromatic structures, humic-like substances and macromolecules. Principal component analysis and correlation analysis indicated that the data from elemental and spectroscopic analysis fell into three main groups, and corresponded to the biodegradation, aromatization, and humification and polymerization state of the composting materials. Hierarchical cluster analysis indicated rapid biodegradation of organic matter during the first eight days, and the formation of aromatic structures, humic-like materials and macromolecules in dissolved organic matter after eight days.

Structural transformation study of water-extractable organic matter during the industrial composting of cattle manure

Various spectroscopic approaches were used to characterize the evolution of water-extractable organic matter (WEOM) during cattle manure composting. Using the results of spectroscopic characterization as bases, multivariate statistical analysis was performed to investigate the correlation among the different parameters related to organic matter transformation. The results show that the composting process degraded lignin, aliphatics, alcohols, and protein-like materials, and increased the amount of water-extractable aromatic compounds and humic-like materials, as well as the humification degree of cattle manure. The degradation process primarily occurred during the first few days of composting, whereas the formation of fulvic- and humic-like substances took place during the later stages. The spectroscopic parameters obtained from the WEOM analysis were divided into two groups: one describes the state of decomposition, and the other reflects the stabilization and maturation of the compost.

The Divergences of Organic Matter Released from Ozonated Biofilter Inoculated with Indigenous Bacteria

In this work, the excitation-emission fluorescent matrix (EEFM) was used to compare the divergence of fluorescent organic properties of the effluents produced from the operation of the bio-stabilizing filter. Four bio-stabilizing filters were simultaneously operated in the combination of both filtered CCL and FS source waters with ozonation (O3/NPDOC=1) and two different indigenous bacteria taken from CCL and FS source water. It found that, two peak locations, 220-230/330nm, 320-330/410-420nm, existed in the effluent of the four bio-stabilizing filters, and one another peak of 280-290/340 nm was appeared in bio-stabilizing filter using FS source water as a substrate. The fluorescent organic matter, with an excitation wavelength of 220-230 nm and 280-290 nm may be attributed as protein-like, while that of 320-330/410-420nm had the possibility of humic-like. The humic-like matter was accumulated in the effluent from the bio-stabilizing filter during the operational process. Bio-stabilizing filter operated with consistent source water and indigenous bacteria could release higher humic-like fluorescent intensity than that with inconsistent source water and indigenous bacteria.