Effect Of Organic Matter Content Research Articles

The Role of a New Stabilizer in Enhancing the Mechanical Performance of Construction Residue Soils.

Urban construction generates significant amounts of construction residue soil. This paper introduces a novel soil stabilizer based on industrial waste to improve its utilization. This stabilizer is primarily composed of blast furnace slag (BFS), steel slag (SS), phosphogypsum (PG), and other additives, which enhance soil strength through physical and chemical processes. This study investigated the mechanical properties of construction residue soil cured with this stabilizer, focusing on the effects of organic matter content (Oo), stabilizer dosage (Oc), and curing age (T) on unconfined compressive strength (UCS). Additionally, water stability and wet-dry cycle tests of the stabilized soil were conducted to assess long-term performance. According to the findings, the UCS increased with the higher stabilizer dosage and longer curing periods but reduced with the higher organic matter content. A stabilizer content of 15-20% is recommended for optimal stabilization efficacy and cost-efficiency in engineering applications. The samples lost their strength when immersed in water. However, adding more stabilizers to the soil can effectively enhance its water stability. Under wet-dry cycle conditions, the UCS initially increased and then decreased, remaining lower than that of samples cured under standard conditions. The findings can provide valuable data for the practical application in construction residual soil stabilization.

Enhancing microbial desalination cell performance through co-culture optimization and response surface methodology (RSM) in high saltwater feed concentration

In response to contemporary water and energy supply challenges, the Microbial Desalination Cell (MDC) emerged as an innovative solution, generating electricity and desalting saline water through wastewater treatment. However, the accumulation of ions during the desalination process adversely affects the biocatalyst performance, imposing scalability limitations on the technology. This study focused on enhancing the system's performance by co-culturing Shewanella oneidensis MR–1 and Escherichia coli. Through the response surface methodology, the effects of organic matter concentration and saltwater feed salinity were systematically investigated by central composite design. The study emphasizes the significant impact of studied factors on system performance. Elevated sodium lactate, sodium acetate concentrations, and salinity positively influence the desalination rate, with NaCl concentration showing an interaction effect with lactate. Positive linear relationships for OCV are observed with lactate and acetate. All factors significantly impact power output, with lactate having the most potent positive effect. Additionally, positive contributions to COD removal are noted for lactate and NaCl concentration and a positive interaction effect. These achievements facilitated the development of a mathematical model to optimize system performance by leveraging co-cultured inoculum and strategic environmental manipulation, overcoming limitations from ion accumulation, and opening the path for further advancements in this field.

Evaluating the effect of organic matter contained in shale on hydraulic fracturing of infill-well

Organic matter which is scattered uniformly in shale can respond to the applied stress and result in the variation of stress field. However, the effects of organic matter content in organic-rich shale on stress interference have not been well considered during developing infill-wells. A fully coupled numerical model is proposed in this paper to consider the whole flow spectrum of shale gas and investigate the effect of organic matter content on stress variation and fracture propagation in infill-well. Through simulating the production and fracturing process with only one set of code, some conclusions can be drawn that the alteration angle of the maximum horizontal principal stress increases and then decreases with the production time. Furthermore, the shrinkage of organic matter enlarges the alteration angle and the magnitude of the maximum horizontal principal stress. Certainly, the optimal fracturing effect in the infill-wells vary due to the different mass fraction of organic matter. This study not only helps to understand the effect of mass fraction of organic matter on stress variation and fracture propagation, but also provides theoretical support for increasing production from shale gas reservoirs.

Optimization of methane production from co-digestion of citrus agro-industrial waste in a two-stage system: Investigation of the effects of organic matter concentration and alkalinization

The essential oils in citrus waste poses challenges for the anaerobic digestion application to energy recovery from these wastes due to the potential to inhibit the bioprocess. The two-stage system is a practical alternative to overcome these limitations of anaerobic co-digestion of citrus peel waste and wastewater. This study proposes to overcome drawbacks associated with the use of these substrates in anaerobic digestion by separating the phases, performing parameters optimization of the methanogenic stage. To obtain optimized conditions for the methanogenic stage, the Rotational Central Composite Design (RCCD) and Response Surface Methodology (RSM) were applied, evaluating the effects of diluting the Fermentation Reactor Content (FRC) of the first stage (35.7%–100%) and alkalinization (up to 0.60 g sodium bicarbonate.gCOD−1), in methane production and organic matter removal. Values from 2100.4 to 6320.6 mLCH4.L−1 were obtained in the experimental design assays, with no inhibition identified by the high substrate concentration, nor by the limonene content (1.5–5.0 mg.L−1). Lower dilution of the fermentation reactor content (90%–100%) resulted in higher accumulated methane production, while the variation in the alkalinization did not imply significant effects on this response. The optimized condition for maximum production potential was obtained with 99.3% of fermentation reactor content and 0.58 gNaCHO3.gCOD−1, reaching a production of 6549.7 mLCH4.L−1, with organic matter removal (rCOD) of 87.1%, and 58.6% of reduction in solid waste content. For this condition, acetogenic metabolism predominance was observed, in the conversion of butyric acid and propionic acid into acetic acid. In the analysis of the microbial community of the optimized condition assay, a high relative abundance of hydrolytic and acidogenic bacteria (AUTHM297, Lachnospiraceae, and Hungateiclostridiaceae) was observed, as well as methanogenic archaea related to acetoclastic, hydrogenotrophic, and methylotrophic methanogenesis (Methanoregula, Methanolinea, Methanomassiliicoccus, Candidatus Methanomethylicus, and Methanofolis).

Discussion of ‘Effect of organic matter content on Atterberg limits and undrained shear strength of river sediment’ by Gang Wang, Xia Bian, Ye-Jiao Wang, Yu-Jun Cui and Ling-Ling Zeng

Discussion of ‘Effect of organic matter content on Atterberg limits and undrained shear strength of river sediment’ by Gang Wang, Xia Bian, Ye-Jiao Wang, Yu-Jun Cui and Ling-Ling Zeng

In Vitro Fungicide Sensitivity and Effect of Organic Matter Concentration on Fungicide Bioavailability in Take-All Root Rot Pathogens Isolated from North Carolina

Take-all root rot (TARR) of ultradwarf bermudagrass is caused by Gaeumannomyces graminis (Gg), Gaeumannomyces graminicola (Ggram), Candidacolonium cynodontis (Cc), and Magnaporthiopsis cynodontis (Mc). Multiple pathogens have recently been associated with this disease, and biological parameters such as fungicide sensitivity have not been explored in ultradwarf bermudagrass. Although fungicides are commonly used to mitigate disease development, high organic matter present in the turfgrass system could limit the bioavailability of fungicides. Fungicide bioavailability can be influenced by organic matter concentration, and the physicochemical properties of fungicides could provide insight into their binding affinity. However, the influence of organic matter content on fungicide bioavailability has not been investigated. Therefore, the in vitro sensitivity of Gg, Ggram, Cc, and Mc to 14 different fungicides across three chemical classes was determined. An in vitro bioavailability assay was developed using three fungicides and three organic matter concentrations. Generally, demethylation inhibitor and quinone outside inhibitor fungicides provided the greatest reduction in mycelial growth, whereas succinate dehydrogenase inhibitors did not reduce mycelial growth. These data can serve as a foundation for TARR pathogen sensitivity to inform in vitro fungicide sensitivity studies and field efficacy trials. Pyraclostrobin and propiconazole have a high affinity to bind to organic matter, which was evident as more fungicide was required to inhibit Gg growth as organic matter concentration increased. This was not observed when evaluating azoxystrobin, which has a lower binding affinity. Understanding how TARR pathogens respond to fungicide in vitro and how organic matter concentration affects in vitro sensitivity will improve fungicide selection for management of TARR.

Strength Properties of Cement-Solidified Dredged Sludge Affected by Curing Temperature

In this study, unconfined compressive strength (qu) tests were conducted to explore the coupling effect of organic matter content (3.7%, 7.7%, 10.7%, and 13.7%) and curing temperature (18 °C, 36 °C, 46 °C) on the development of early and mid-late strength of cement-solidified dredged sludge (cement-stabilized clay, or CSC). The microstructure of the CSC containing organic matter at different curing temperatures was also analyzed. The results show that qu of CSC decreases with the increase in organic matter content (Co). The strength growth rate of CSC in the mid-late stage (≥14 days) is small when Co ≥ 7.7%, and it is difficult to increase this strength growth rate even if the curing temperature is increased up to 46 °C. There is a cement incorporation ratio threshold of 15% for qu of CSC containing organic matter (Co = 7.7%), which is not affected by curing temperature; increasing the cement incorporation ratio (to 20%) cannot increase qu significantly. The CSC with high curing temperature has more hydration products and higher structural compactness, and it can obtain higher qu in the early and mid-late stages. A high curing temperature can increase the early strength growth rate and shorten the curing age for CSC containing organic matter.

KARAKTERISTIK STRUKTUR KOMUNITAS MAKROZOOBENTOS DI PERAIRAN EKOSISTEM MANGROVE GILI LAWANG, LOMBOK TIMUR

The role of the mangrove ecosystem as an ecological link through high productivity compared to other ecosystems has had a major impact on the existence of the mangrove ecosystem distribution. This study aims to find out the type of organic ingredient content and abundance of macrozoobenthos and find out the relationship of organic ingredient content to the abundance of macrozoobenthos. The research was carried out in November 2021 using a purposive sampling technique method with a total of 5 stations. The samples taken were the sediments substrate and macrozoobenthos. The results shown that the organic content is dominated by saturated textures, muddy sand textures and saturated clay textures with an average organic content ranging from 1.24% - 1.90%. There were 15 types of macrozoobenthos found and dominated by the Gastropod class with an average abundance of macrozoobenthos ranging from 202 ind/m2 - 525 ind/m2. The types of macrozoobenthos found were Nassarius distortus, Anadara sp, Mesodesma sp, Mytillus sp, Donax sp, Abra soyoae, Cerithideopsilla djadjariensis, Telescopium telescopium, Cassidula nucleus, Cassidula angulifera, Litttoridina sp., Potamopyrgus sp., Melanoides sp., Battilaria zonalis dan Lumbriculus sp. The effect of organic matter content on the abundance of macrozoobenthos by 10.7% and 89.3% was more influenced by physic-chemical factors in Gili Lawang waters.

Effect of organic matter content on Atterberg limits and undrained shear strength of river sediment

The Atterberg limits and the undrained shear strength are crucial soil properties in the preloading design of reclamation foundation projects using dredged river sediment. These properties can be significantly affected by the presence of organic matter in the sediment. This study investigates the physical properties and undrained shear strength of river sediment, based on data from a series of fall cone tests performed on river sediment with different organic matter contents, and undrained shear strength data for reconstituted clay collected from the literature. It was found that the liquid limit, plastic limit, and plasticity index increase with an increase in organic matter content. The effect of organic matter on the undrained shear strength of remolded soil at a given water content can be attributed to the effect of organic matter on the liquid and plastic limits. The undrained shear strength is a function of the liquid and plastic limits; it can be normalized by the liquidity index, irrespective of the organic matter content. Highlights Investigating role of organic matter in the Atterberg limits Investigating role of organic matter in shear strength Understanding key factors of controlling shear strength Establishing organic matter–liquidity index–shear strength interrelations

The Crucial Role of Soil Organic Matter in Satisfying the Phosphorus Requirements of Olive Trees (Olea europaea L.)

Under high organic matter content, even under low extractable soil P concentrations, sufficient or over-sufficient foliar P levels may be found. This multi-year study aimed at examining the effects of organic matter content and irrigation management on (a) soil fertility, (b) P-cycle related soil enzymes (acid and alkaline phosphatase, pyrophosphatase) and (c) foliar nutrient concentrations. Irrigated and non-irrigated groves of fully productive trees of the cultivar “Chondrolia Chalkidikis” with low organic matter (LOM < 1.5%), medium organic matter (1.5% < MOM < 2.5%) and high organic matter (HOM > 2.5%) were selected for the experimentation. It was hypothesized that olive groves receiving high inorganic fertilization and irrigation inputs (usually with medium to relatively low organic matter content) would show higher soil and foliar P concentrations compared to the non-irrigated groves with higher organic matter content receiving manure applications. Most of the soil variables (including the three enzymes’ activities) were affected by differences in organic matter content. However, organic matter content did not show a significant influence on foliar nutrient concentrations. Olive trees, especially those cultivated in soils with high organic matter content (receiving organic fertilization), can over-satisfy their P nutritional needs, even though soil analyses show low soil extractable P concentrations, probably due to the high enzymatic activity of acid and alkaline phosphatases. The practical conclusion of this study is that P fertilizer recommendations should be primarily based on foliar P rather than on extractable soil P.

Effect of organic matter concentration and characteristics on mercury mobilization and methylmercury production at an abandoned mine site.

Thousands of abandoned mines throughout the western region of North America contain elevated total-mercury (THg) concentrations. Mercury is mobilized from these sites primarily due to erosion of particulate-bound Hg (THg-P). Organic matter-based soil amendments can promote vegetation growth on mine tailings, reducing erosion and subsequent loading of THg-P into downstream waterbodies. However, the introduction of a labile carbon source may stimulate microbial activity that can produce methylmercury (MeHg)-the more toxic and bioaccumulative form of Hg. Our objectives were to investigate how additions of different organic matter substrates impact Hg mobilization and methylation using a combination of field observations and controlled experiments. Field measurements of water, sediment, and porewater were collected downstream of the site and multi-year monitoring (and load calculations) were conducted at a downstream gaging station. MeHg production was assessed using stable isotope methylation assays and mesocosm experiments that were conducted using different types of organic carbon soil amendments mixed with materials from the mine site. The results showed that >80% of the THg mobilized from the mine was bound to particles and that >90% of the annual Hg loading occurred during the period of elevated discharge during spring snowmelt. Methylation rates varied between different types of soil amendments and were correlated with the components of excitation emission matrices (EEMs) associated with humic acid fractions of organic matter. The mesocosm experiments showed that under anoxic conditions carbon amendments to tailings could significantly increase porewater MeHg concentrations (up to 13±3ng/L). In addition, the carbon amendments significantly increased THg partitioning into porewater. Overall, these results indicate that soil amendment applications to reduce surface erosion at abandoned mine sites could be effective at reducing particulate Hg mobilization to downstream waterbodies; however, some types of carbon amendments can significantly increase Hg methylation as well as increase the mobilization of dissolved THg from the site.

Effect of Organic Matter Content on the Spectral Signature of Iron Oxides across the VIS–NIR Spectral Region in Artificial Mixtures: An Example from a Red Soil from Israel

The investigation of iron oxides in soil using spectral reflectance is very common. Their spectral signal is significant across the visible–near infrared (VIS–NIR) spectral range (400–1000 nm). However, this range overlaps with other soil chromophores, such as those for water and soil organic matter (SOM). This study aimed to investigate the effect of different SOM species on red soil from Israel, which is rich in hematite iron oxide, under air-dried conditions. We constructed datasets of artificially mixed soil and organic matter (OM) with different percentages of added compost from two sources (referred to as A2 and A5). Eighty subsamples of mixed soil–OM were prepared for each of the OM (compost) types. To investigate the effect of OM on the strong iron-oxide absorbance at 880 nm, we generated two indices: CRDC, the absorbance spectral depth change at 880 nm after continuous removal, and NRIR, the normalized red index ratio using 880 and 780 nm wavelengths. The different OM types influenced the soil reflectance differently. At low %SOM, up to 1.5%, the OM types behaved more similarly, but as the OM content increased, their effect on the iron-oxide signal was greater, enhancing the significant differences between the two OM sources. Moreover, as the SOM content increased, the iron-oxide signal decreased until it was completely masked out from the reflectance spectrum. The masking point was observed at different SOM contents: 4% for A5 and 8% for A2. A mechanism that explains the indirect chromophore activity of SOM in the visible region, which is related to the iron-oxide spectral features, was provided. We also compared the use of synthetic linear-mixing practices (soil–OM) to the authentic mixed samples. The synthetic mixture could not imitate the authentic soil reflectance status, especially across the overlapping spectral position of the iron oxides and OM, and hence may hinder real conditions.

Highly efficient and low-energy nitrogen removal of sludge reduction liquid by coupling denitrification- partial nitrification-Anammox in an innovative auto-recycling integration device with different partitions

The denitrification (DN), partial nitrification (PN) and Anammox processes were coupled in an auto-recycling integration device to remove nitrogen from the supernatant of sludge reduction pretreatment. The nitrogen removal performance of the device and the effect of organic matter concentration on the nitrogen transformation were discussed. The results showed that DN, PN and Anammox are well coupled and total nitrogen (TN) removal rate reached 0.85 kg/(m3·d). The pre-DN process can achieve the removal of NO3−-N produced by the back-end PN-Anammox process without the need of reflux pump drive. When the influent NH4+-N concentration was approximately 400 mg/L, the effluent TN concentration was less than 20 mg/L. The fluctuation of organic matter led to changes of nitrogen transformation in the system, and the best ratio of influent CODbio/TN was 0.7–0.9. Nitrosomonas and Candidatus Brocadia played important roles in the nitrogen removal process as the main functional microorganisms of PN and Anammox, respectively.

Influencing Factors of Gas Adsorption Capacity of Marine Organic Shale: A Case Study of Dingshan Area, Southeast Sichuan

Xie, J.; Qin, Q., and Fan, C., 2019. Influencing factors of gas adsorption capacity of marine organic shale: A case study of Dingshan Area, Southeast Sichuan. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 507–511. Coconut Creek (Florida), ISSN 0749-0208.The gas bearing property of marine shale is very important to the reserve calculation of shale gas field, which is directly related to the productivity and decline law of shale gas. The development of coastal shale gas is also the reserve field of shale gas exploration at present. Based on the conventional marine shale, this study adopts cylindrical shale core to measure the adsorption gas volume by testing the gas volume change in the process of pressure reduction and desorption of marine shale gas, simulates the conditions of different temperature, pressure, water cut, real pore structure and so on, and eliminates the negative adsorption anomaly of isotherm adsorption curve. The effects of organic matter content, pressure, temperature, water content and gas composition on the adsorption capacity of marine shale were analyzed. The experimental results show that the pressure condition controls the desorption process of shale gas, and the increase of pressure suppresses the desorption of shale gas. Within a certain range, with the increase of pressure, the adsorption gas volume of marine shale also increases. A large number of micropores of organic matter are developed, which greatly increases the specific surface area of organic matter. Under certain maturity conditions, with the increase of organic matter content, the adsorption volume of shale increases. The increase of temperature increases the activation energy of molecular surface and accelerates the desorption process of shale gas. When the shale is water-bearing, the water molecules occupy the active adsorption site on the shale mineral surface, which reduces the shale gas adsorption capacity. The research results have certain theoretical guidance for the exploration and development of coastal shale gas in the next stage.

Compressibility behaviour of natural and stabilized dredged soils in different organic matter contents

Dredged soils are re-usable, alternative, eco-friendly materials for various civil engineering applications. However, they exhibit high compressibility and low shear strength because of their high organic matter content. An accurate geotechnical characterization of dredged soils is fundamental before being used in engineering applications. The main objective of this study is to investigate the effects of organic matter content (OMC) on the geotechnical properties and compressibility behavior of dredged material in İzmir Bay. In order to improve the geotechnical properties and compressibility behaviour of dredged soil, samples were mixed with lime (L), thermal power plant fly ash (T) and volcanic slag (V). The structure and chemical compositions of dredged samples with different OMC (0%, 4%, 7%, and 11%) were investigated with SEM, XRD and FTIR analysis. Consolidation tests were conducted on specimens with various OMC and different percentages (5, 10, 15 and 20%) of three additives (L, T, and V). The results showed that as the OMC increased, the consistency limits increased and the specific gravity decreased. The compression indexes increase with the OMC increasing, are ranged between 0.32 and 0.10. While the L and T have positive effects on the compression index (Cc), the V addition acts adversely which increasedthe compressibility.

Effect of Organic Matter Content on Enzymatic Biocementation Process Applied to Coarse-Grained Soils

AbstractThis work studies the effect of the organic matter content on the efficiency of the biocementation process due to the precipitation of calcium carbonate (CaCO3) induced by the urease enzyme...

Effect of organic matter concentration on agricultural limestone dissolution in laboratory soil-water systems

Laboratory soil–water systems in which soil organic matter was increased by 0.0%, 0.5%, 1.0%, 2.0% and 4.0% by adding dry, chopped ryegrass (Lolium perenne) shoots to sandy soil containing 0.06% organic matter. Agricultural limestone was added to the systems, and pH, alkalinity and hardness of the water were monitored for 65 days. The pH, alkalinity and hardness increased with greater soil organic matter concentration. Amounts of carbon dioxide released by microbial respiration increased at the higher soil organic matter concentrations, and this resulted in more rapid and greater solubility of agricultural limestone. The results suggest that greater soil organic matter concentrations in ponds favour the rate and extent of agricultural limestone dissolution.

Effects of organic matter on mechanical properties of dredged sediments for beneficial use in road construction

ABSTRACTIn France, the road construction sector is the greatest consumer of granular materials, with a yearly consumption of about 200 million tons. With the shortage of standard materials, the valorisation of dredged sediments for road construction could constitute an interesting solution. Dredged sediments generally consist of a mineral phase, an organic phase (in various forms) and a liquid phase (water). The presence of organic matter (OM) in sediments, even in small amounts, affects their engineering properties. The main objective of this study is to investigate the effects of organic matter content on the engineering properties of dredged sediments. For this purpose, a specific methodology to reconstitute samples with different amounts of organic matter contents is proposed. The evaluation of the effects of organic matter content in term of compressibility, shear strength, compaction and bearing capacity show that even for high amount of organic matter the performances of the studied samples are compatible with the use in road construction sector.

Organic matter affects fiddler crab distribution? Results from field and laboratorial trials

Fiddler crabs are a key benthic macrofauna group in estuarine environments. Species distribution is determined by relatively distinct zones, based on biotic and abiotic factors. As sediment organic matter is thought to be one of the most important zoning factors of mangrove macrofauna, we tested the effects of organic matter content on the intra-specific distribution of the fiddler crabs Leptuca thayeri and Leptuca uruguayensis. Organic matter content and crab abundance and size were assessed in both species by field observations, while the choice of adult or juvenile L. uruguayensis for high -or low- organic matter was tested in the laboratory. Both species showed no relationship between organic matter and crab abundance or size. Furthermore, L. uruguayensis juveniles or adults did not show any preference for specific organic matter content. Therefore, fiddler crabs intra-specific distribution in mangrove forests is not dependent of the water-land gradient decrease of organic matter.

Performance and microbial features of the partial nitritation-anammox process treating fish canning wastewater with variable salt concentrations

The partial nitritation-anammox (PN-AMX) process applied to wastewaters with high NaCl concentration was studied until now using simulated media, without considering the effect of organic matter concentration and the shift in microbial populations. This research work presents results on the application of this process to the treatment of saline industrial wastewater. Obtained results indicated that the PN-AMX process has the capability to recover its initial activity after a sudden/acute salt inhibition event (up to 16 g NaCl/L). With a progressive salt concentration increase for 150 days, the PN-AMX process was able to remove the 80% of the nitrogen at 7–9 g NaCl/L. The microbiological data indicated that NaCl and ammonia concentrations and temperature are important factors shaping PN-AMX communities. Thus, the NOB abundance (Nitrospira) decreases with the increase of the salt concentration, while heterotrophic denitrifiers are able to outcompete anammox after a peak of organic matter in the feeding.