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Innovative and cost-effective approaches to enhance nutrient removal and energy efficiency in conventional wastewater treatment plants
(Academic Press, 2025) Alver, Alper; Küçükbayrak, Mustafa
The 42 Evler Wastewater Treatment Plant (WWTP), originally operated as a conventional activated sludge (CAS) system, was transformed into an advanced biological system using the Modified Ludzack-Ettinger (MLE) process scheme, significantly improving nutrient removal and energy efficiency. Integrating anoxic-aerobic zones and optimizing microbial dynamics enhanced treatment performance, with total nitrogen (TN) and total phosphorus (TP) removal efficiencies increasing from 28.1 % to over 80 % and from 56.4 % to 89.6 %, respectively. These improvements were achieved alongside a 32.9 % reduction in energy consumption. Detailed microbial analyses identified key new species, such as Nitrosomonas and Thiobacillus, whose roles in nitrification and denitrification pathways were pivotal for improving treatment performance. Integrating anoxic-aerobic zones, advanced aeration systems, and optimized sludge management further contributed to the system's sustainability. Evaluating pollutant removal efficiencies before and after the upgrade, supported by statistical analyses, confirmed significant improvements in BOD5, COD, TN, TP, and TSS removal. The microbial community was comprehensively assessed, revealing the specific roles of microorganisms in nutrient removal and process optimization. These advancements align with stringent discharge standards and global environmental goals, demonstrating how microbial insights and process innovations can modernize wastewater treatment. The upgraded system provides a scalable and efficient framework for addressing environmental and operational challenges in wastewater management.
Investigation of adsorption behavior of eriochrome black T on mesoporous silica aerogel: experimental and molecular modeling studies
(Yaycı, 2024) Sönmez, G.; Akyüz, L.
Remediating organic dye pollution remains a concern in contemporary water management practices. Developing low-cost and high-surface-area adsorbents synthesised by nanotechnology to eliminate organic dyes is an essential issue in water treatment. Recently, silica aerogels, a kind of nanomaterials, have been investigated as adsorbents due to their high porosity, high surface area, and low cost. This study aimed to synthesize and characterize tetraethoxysilane (TEOS)-based silica aerogel (SA) to assess its efficacy in removing eriochrome black T (EBT), which is a potentially hazardous dye. Based on adsorption studies, the optimal adsorption conditions were found to be 0.2 g adsorbent dosage, pH 2, 120 min contact time, 10 mg L-1 initial EBT concentration, and a temperature of 40 degrees C. The adsorption data were best fitted with a remarkably high correlation coefficient of R2 = 0.999 in the pseudo-second-order model. According to the results of the adsorption isotherm model analysis, the R2 values for the Temkin, Freundlich, and Langmuir models were determined to be 0.971, 0.935, and 0.954, respectively, particularly at the optimally determined temperature of 40 degrees C. Thermodynamically, the process is exothermic and spontaneous. In addition to experimental studies, the WB97x-D level of the Density Functional Theory was used to elucidate the detailed adsorption mechanism between SA and EBT in the water phase. The experimental results are consistent with the computational parameters describing the primary adsorption mechanism, including physisorption processes via electrostatic attraction, van der Waals interactions, and hydrogen bonding.
The Relationship of the Change in Hydrogeochemical Features and Lithium Values of Kızılırmak Basin (Nevsehir-Central Anatolia) Water with Tectonic Fields
(Technical University of Kosice, 2024) Demircioğlu, Ramazan; Elhatip, Hatim
In this study, in particular, the relationship between high lithium values and geological environments was examined. To determine this, the geology, structural geology, hydrogeology, and hydrogeochemistry of the area in the north of the Gülşehir-Yeşilöz sub-basin of the Kızılırmak Basin were investigated. For hydrogeological studies, 19 water samples were collected in May and September. Tectonically, this area has a horst-graben structure. The relationships between the water analysis values of the study area and the tectonic areas were investigated. In particular, the lithium content of the waters in the study area was investigated. Hydrogeochemical properties and seasonal changes in water resources were studied in detail, and their relationship with tectonic areas was evaluated. Water analyses were carried out during wet and dry periods to determine temporal hydrogeochemical changes. According to the analysis, the waters in the area are of Ca-HCO3 and Ca-Mg-HCO3 facies. In addition, there are water samples with high lithium content in the study area. IDW and Kernel diagrams of these were prepared. It was found that these high values were influenced by the rocks formed in the ancient sea and saline lake environments. The region with the highest lithium value is in the formations that represent the former salt lake environment. High lithium (Li) values are generally higher in the region within the Kızılırmak graben. Lithium values in this area were determined as 241.3 µg/L, 154.5 µg/L, 155.2 µg/L, 156.8 µg/L, and 155.6 µg/L.
Bibliometric Insights into Microplastic Pollution in Freshwater Ecosystems
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Yıldırım, Gökhan; Anindita, Monisha; Pan, Xiao; Rahman, Sumya; Alim, Mohammad A.; Shaik, Rehana; Rahman, Ataur
Microplastic pollution in freshwater ecosystems has emerged as a significant environmental concern, warranting comprehensive investigation, and understanding. This study employs bibliometric analysis to systematically review and synthesize the existing literature on microplastic pollution in freshwater environments from 2013 to 2023. The exponential growth in research output was uncovered by analyzing 885 documents sourced from the Web of Science database, with an average annual growth rate of 73.13% and an average document citation of 30.17. Our findings highlight the dominance of primary and secondary microplastics as pollutants, their ecological consequences, and the resultant socio-economic implications. Notably, the Science of the Total Environment and Environmental Pollution journals emerge as leading publication venues, while China, Germany, and the USA lead in research contributions, underlining the global nature of microplastic pollution research. The analysis further outlines the most commonly cited works, identifying pivotal studies that have shaped current understanding and future research directions. This bibliometric analysis provides a comprehensive overview of the research landscape on microplastic pollution in freshwater ecosystems, helping researchers to identify knowledge gaps and emerging trends. These insights can guide future research directions and inform policymakers and stakeholders on where scientific efforts should be concentrated to better understand and address the impacts of microplastic pollution.
Mapping of heavy metal pollution density and source distribution of campus soil using geographical information system
(Nature Research, 2024) Gök, Gülden; Tulun, Şevket; Çelebi, Hakan
In this study, the pollution intensity, spatial distribution, and index-based risk distribution in campuses, which are a small prototype of cities, were mapped and the sources of heavy metals in the soil were investigated. Soil samples were taken from 9 different points from the Aksaray University Central campus, which was determined as the study area. It has been determined that the pH value in the collected soil samples varies between 8.7 and 11.0. This situation created an effect on reducing the accumulation and mobility of heavy metals in the soil. When the study area was evaluated based on the geo-accumulation index, Pb heavy metal was much denser in the places indicated as circulation areas and where students were actively present. Based on the pollution load index, it was concluded that 75% of the study area was moderately/highly polluted, and the rest consisted of unpolluted soils. Pearson correlation analysis and APCS-MLR analyses conducted to determine the source distribution showed that the contributions of natural sources, mixed sources of industrial and traffic activities, agricultural activity-based sources, and other sources were 57.49%, 21.44%, 12.67%, and 8.40%, respectively. Pb is mainly related to the mixed sources of industrial and traffic activities. Therefore, to clear up its long-term impact on the accumulation of heavy metals in the soil, it is important to conduct continuous heavy metal monitoring in the soil throughout the campus.
Fıstık kabuğu ile sulardan metilen mavisi gideriminin atık yönetimi yaklaşımıyla incelenmesi
(Uludağ Üniversitesi, 2024) Çelebi, Hakan; Tulun, Şevket; Şimşek, İsmail; Bahadır, Tolga; Bilican, İsmail
Boyar maddelerin kullanımının yaygınlaşması, özellikle tekstil endüstrisinin gelişmesi su kirliliğinin en önemli nedenlerinden bir olan boya kirliliğini oluşturmaktadır. Günümüzde metilen mavisi (MM), tekstil endüstrisinde yaygın olarak kullanılan boyar maddedir. Bu çalışmada, atık olarak kabul edilen ham yer fıstığı kabuğunun (YFK) adsorbent olarak kullanılarak metilen mavisinin (MM) giderim şartları incelenmiştir. Herhangi bir işlem yapılmadan alınan YFK adsorbentinin farklı dozlarda (0,1, 0,5, 1, 2, 3, 5 g), işletme sürelerinde (5, 10, 15, 30, 45, 60, 90, 120, 150 dk), pH değerlerinde (2, 4, 6, 8, 10, 12) ve sıcaklıklarında (20, 25, 30, 35, 40 °C) giderim verimine etkileri araştırılmıştır. Yapılan çalışmalarda, en uygun adsorpsiyon şartları: YFK miktarı 0,5 g, işletme süresi 15 dakika, pH 4, sıcaklık 20 °C olarak bulunmuştur. İzoterm modellerinin korelasyon değerleri incelendiğinde en yüksek korelasyon değeri Langmuir izotermine (R2=0,9999) olduğu belirlenmiştir. Gerçekleşen adsorpsiyon mekanizması YFK’nın yüzeyinde tek bir tabaka halinde MM tutulduğu sonucuna varılmıştır. Herhangi bir işlem yapılmadan kullanılan YFK’nın yeşil atık yönetimi yaklaşımı ile boyar madde giderimi için uygun bir adsorbent olarak kullanılabileceği belirlenmiştir.
Sulardan Bentonit ile Nikel ve Kadmiyum gideriminde sıcaklık, doz, boyut ve temas süresinin etkilerinin incelenmesi
(Afyon Kocatepe Üniversitesi, 2024) Güllü, Özlem; Çetin Aslan, Nahide Feyza
Ağır metaller, birikim özelliği ve sucul ortamlardan uzaklaştırılmasındaki güçlük gibi nedenlerle suların kalitesinin bozulup kirlenmesine yol açmaktadır. Nikel ve kadmiyum da bu ağır metalar arasında yer almaktadır. Adsorban olarak Eskişehir bölgesinden temin edilen bentonitin kullanıldığı bu çalışmada sentetik olarak hazırlanan sudaki nikel ve kadmiyumun giderimi amaçlanmıştır. Bentonit kili üzerine nikel ve kadmiyumun maksimum adsorpsiyonunu sağlamak amacıyla pH değeri, adsorban dozu, karıştırma süresi, hız ve metal iyonu konsantrasyonu gibi parametreler incelenmiş, analiz edilmiş ve optimizasyonu sağlanmıştır. Deneysel veriler Langmuir ve Freundlich adsorpsiyon izotermine uyarlamıştır. 0.1 Adsorban boyutu deneylerinde ise en yüksek verim, Nikel için 0,5 mm olarak belirlenirken kadmiyum için ise >2 mm boyutta tespit edilmiştir. Deneysel verilerin Langmuir ve Freundlich adsorpsiyon modellerine uyduğu görülmektedir. Çalışma sonucunda, Eskişehir bölgesinden elde edilen bentonit kilinin sulu çözeltiden kadmiyumun ve nikelin uzaklaştırılması için etkili bir şekilde kullanılabileceği ortaya konmuştur.
Sentetik atıksulardan reaktif sarı 145 boyasının uzaklaştırılması: yer fıstığı kabuklarının adsorban olarak değerlendirilmesi
(Süleyman Demirel Üniversitesi Mühendislik Fakültesi, 2024) Çelebi, Hakan; Bilican, İsmail; Şimşek, İsmail; Bahadır, Tolga; Tulun, Şevket
Hem sektörel hem de evsel kullanımlarla açığa çıkan tarım ve gıda atıkları besin zincirinin en önemli atıklarındandır. Tüm dünyada değerli özelliklere sahip bu atıklar doğrudan çöp alanlarına atılmaktadır. Bu çalışmada, atık olarak çöpe atılan yer fıstığı kabukları toz formda Reaktif Sarı 145’in sentetik çözeltiden giderimi amacıyla kullanılmıştır. Değerlendirme için, sabit karıştırma hızı (150±5 rpm) ve 10±3 mg/L Reaktif Sarı 145 dozunda; pH, temas süresi, fıstık kabuğu dozu ve sıcaklık faktörlerinin etkileri incelenmiştir. Fıstık kabuğunun yapısı ve yüzey kimyası FTIR, pHZPC, ve SEM ile ortaya konulmuştur. FTIR pikleri, fıstık kabuğu yüzeyi üzerinde Reaktif Sarı 145’in tutunabildiğini gösteren spesifik fonksiyonel grupların varlığını ispatlamıştır. Fıstık kabuğu yüzeyindeki gözenekli yapının Reaktif Sarı 145 giderimi için avantajlı olduğu görülmüştür. Optimum şartlarda (Fıstık kabuğu dozu: 0,5 g, pH: 2,0, süre: 30 dakika, sıcaklık: 20 oC) Fıstık kabuğu için yaklaşık %75 Reaktif Sarı 145 verimi elde edilmiştir. Fizisorpsiyonun ön planda olduğu ve tek katmanlı adsorpsiyonun gerçekleştiği sürecin Langmuir ve yalancı ikinci derece modellerine uyduğu görülmektedir. Termodinamik verileri sürecin kendiliğinden ve endotermik gerçekleştiğini göstermiştir. Maksimum adsorpsiyon kapasitesi Reaktif Sarı 145 için 9,438 mg/g olarak tespit edilmiştir. Sonuçlar, fıstık kabuğunun, Reaktif Sarı 145 giderimi için hem umut verici hem de alternatif çevre dostu bir adsorbent olduğunu desteklemektedir.
Quantifying water footprint: A study on the academic and administrative personnel at Konya Technical University
(Techno Press, 2024) Mesutoğlu, Özgül Çimen
This study endeavours to quantify the water footprint of academic and administrative personnel at Konya Technical University. Water footprint assessment, a critical metric for evaluating human impact on water resources, is increasingly recognized as a vital aspect of sustainable resource management. The research involves surveying participants on their water consumption habits, particularly focusing on preferences related to food and sugar intake. Preliminary findings indicate diverse responses in terms of food preference, with a majority favouring low intake. The study aimed to determine the water footprint of the campus in relation to personal consumption behaviours by asking the questions in the "Water Footprint Network (WFN)" to a total of 476 people at the campus, including both the academic and administrative staff. According to the WFN, the average water footprint of the staff was determined as 1694 m3/year.
Efectiveness of electrochemical softening for removing hardness in real groundwater
(Efectiveness of electrochemical softening for removing hardness in real groundwater, 2024) Ulusoy, Merve; Şimşek, İsmail
The applicability of electrochemical treatment which stands out with its advantages over other methods to the removal of hardness in real groundwater was investigated in this study. This treatment method was directly applied in a stainless steel cell used as the anode. Spiral stainless steel with a large surface area was utilized as the cathode. The effects of pH (5.00–11.00), current density (1.89–15.15 mA cm?2), HCO3/Hardness ratio: (0.8/1–1.4/1), and operating time (5–40 min.) parameters on the removal efficiency were investigated. As a result of the experiments, the optimal conditions (initial pH: 7.24, current density: 11.36 mA cm?2, HCO3/Hardness ratio: 1/1, operating time: 20 min.) were determined. Under these conditions, 90% hardness removal and 92% alkalinity removal efficiencies were achieved. The energy consumption for electrochemical softening of 1 L groundwater was calculated as 0.0379 kWh L?1, and the energy consumption per 1 kg of CaCO3 was calculated as 56.90 kWh kg?1CaCO3. Additionally, the cathode surface to which the hardness causing ions adsorbed was imaged using Scanning Electron Microscopy, and Fourier Transform Infrared Spectroscopy analysis of the precipitate on the cathode was performed. The obtained experimental data were statistically evaluated using the multiple linear regression model and the most important independent variable was determined as time.
Assessment and modeling of benzene micropollutant in surface waters proximal to coal-fired thermal power plants
(Taylor and Francis Ltd., 2024) Çimen Mesutoğlu, Özgül; Gök, Oğuzhan
Micropollutants of priority have gained significant attention due to their rising concentrations and persistence in aquatic environments. Among these significant micro-pollutants is benzene, released into the environment because of mining activities, thermal power plants, and certain industrial operations, thereby contributing to environmental contamination. This study monitored benzene concentrations in the Orhaneli River over a year, employing an artificial neural network (ANN) approach to formulate a predictive model for benzene micropollutant concentrations. To provide input to the ANN, Principal Component Analysis (PCA) was employed, utilizing parameters such as precipitation, temperature, humidity, pH, flow rate, dissolved oxygen, conductivity, total organic carbon, and total nitrogen. Eleven backpropagation algorithms were compared, with the Levenberg-Marquardt algorithm identified as the optimal training algorithm. For the selected training algorithm, an optimized number of 6 neurons in the hidden layer provided the best predictions for benzene concentrations. The three-layered optimized ANN model achieved an impressive correlation coefficient (R2) of 0.9889.
Investigation of methylene blue adsorption from aqueous solutions with different carbon nanocomposites
(Springer Nature, 2024) Namal, Osman Önder
In this study, adsorption of methylene blue dye from aqueous solutions was studied using two different nanocomposite materials as graphene oxide–clay (GO-C) and graphene oxide–pumice (GO-P). The experimental studies were carried out on the effect of composition ratio, adsorption kinetics, adsorption isotherms and adsorption thermodynamics together with the effect of solution pH. The adsorption systems for both nanocomposite materials reached equilibrium within about the first 30 min, and the obtained equilibrium concentrations were 78.4 and 21.2 mg/g, respectively, for GO-C and GO-P. It has been concluded that pore diffusion is not only controlling mechanism for the diffusion of dye molecules and the chemisorption was determined as the rate-limiting step. The maximum adsorption capacities for GO-C and GO-P were determined as 89.28 and 22.57 mg/g, respectively, according to results from the Langmuir isotherm model. Thermodynamic findings revealed that the adsorption systems have an endothermic nature. Adsorption capacities significantly increased above pH 8, reaching their maximum values at pH 12 (140.81 ve 142.32 mg/g for GO-C and GO-P, respectively).
Utilization of peanut shell: investigating the adsorption mechanism and optimization of red 195 and reactive black-5
(Springer Nature, 2024) Çelebi, H.; Bahadır, T.; Tulun, Ş.; Şimşek, İ.; Bilican, I.
In this study, peanut shells (PS) called waste were utilized in powdered form for the removal of Red 195 (R-195) and Reactive Black-5 (RB-5) from synthetic wastewater solutions. Various operational parameters such as PS dosage (0.1–5.0 g), pH (2–12), contact time (5–150 min.), and temperature (20–40 °C) were investigated to optimize the batch adsorption process. FTIR, TGA, pHZPC, and SEM analyses were conducted to investigate the structural features and surface chemistry of PS. FTIR analyses revealed the existence of specific functional groups on the PS surface capable of successfully adsorbing R-195 and RB-5. TGA results demonstrated thermal stability for all prepared samples. SEM highlighted the porous structure of PS, which is advantageous for dye adsorption. The process, characterized by physical adsorption predominance and single-layer adsorption, was well-fitted to Langmuir and PFO for both dyes. Maximum removal efficiencies of 95.30% for RB-5 at pH 2.0 and 94.00% for R-195 at pH 2.5 were determined. Thermodynamic factors suggested that the adsorption of R-195 and RB-5 onto PS occurred spontaneously and exhibited an endothermic nature. Due to the interaction with a higher number of functional groups, PS exhibited a higher maximum adsorption capacity for R-195 (27.027 mg/g) compared to RB-5 (10.989 mg/g). The results support the idea that PS can act as an efficient and eco-friendly adsorbent, capable of removing both R-195 and RB-5.
Estimation of the carbon footprint from road transportation: a case study
(Inderscience Publishers, 2024) Aksoy, Samed; Koçak, Ebru
This research aims to estimate the carbon footprint of road transport in Aksaray, Turkey. The study used the Intergovernmental Panel on Climate Change tier 1 and tier 2 methodologies and found alarming increases in CO2 emissions from benzene and diesel, indicating a significant environmental impact. The results also highlight the need for ongoing monitoring and regulation of benzene and LPG emissions due to methodological differences. However, diesel emissions showed consistent assessment approaches between tier 1 and tier 2 methodologies. These findings provide valuable insights into the region’s evolving carbon footprint, emphasising the need for precise methodologies for effective environmental management.
Biopolymeric Composite Columns for Improving Water Quality in a Freshwater Stream Receiving Wastewater Treatment Plant Effluents
(Springer, 2024) Akpınar, Şahin; Gürbüz, Fatma; Özcan, Samet; Odabaşı, Mehmet
Inefficiently treated wastewater, which contains a high concentration of pollutants, is hazardous when it is mixed with the clean water of rivers and lakes. Nitrate in particular is a major global problem that leads to eutrophication and poses a threat to both aquatic ecosystems and human health. To address this issue, this work assessed the efficiency of polymeric cryogel (PC) and biopolymer (EPS)-blended composites (EPS@PC) in removing nitrates. Tests were also conducted to quantify the decrease in phosphate, chloride ions, and chemical oxygen demand (COD) in real water samples taken from the Ankara stream, which receives effluents from both urban (UWTP) and industrial (IWTP) wastewater treatment plants. Five different columns with varying adsorptive properties were prepared, some of which were combined with iron. The EPS-@PC-C5 column demonstrated the highest adsorption ratio for nitrate removal compared to the other tested columns. The EPS@PC-C5 achieved a high removal efficiency of 126.38 mg nitrate/g and showed COD reduction ranging from 60.2 to 94.1%. The removal ratio of chloride concentration varied between 56.0 and 75.7%, while the removal of phosphates ranged from 87 to 99%. Columns composed of EPS (EPS@PC) with both negatively and positively charged ligands are dependable and suitable options for water remediation.
Prediction of daily fine particulate matter (PM2.5) concentration in Aksaray, Turkey: Temporal variation, meteorological dependence, and employing artificial neural network
(John Wiley and Sons Inc, 2024) Koçak, Ebru
This study analyzed the temporal variation and prediction of fine particulate matter (PM2.5) concentrations in Aksaray, Turkey, a city in Central Anatolia. The relationship between PM2.5 and meteorological parameters such as temperature, humidity, wind speed, and wind direction was investigated. An artificial neural network (ANN) model was developed to predict PM2.5 levels based on meteorological data and air pollutant information. Seasonal and diurnal patterns of PM2.5 concentrations were observed, with higher values recorded during the winter and lower values during the summer. Additionally, higher levels were observed in the morning and evening, while lower levels were recorded in the afternoon. The variations in meteorological parameters, especially temperature and wind speed, significantly influenced PM2.5 levels. To predict hourly PM2.5 concentrations, single and multiple data imputation techniques were employed in combination with resilient back-propagation (RPROP-ANN). The neural network was applied, consisting of one input layer comprising 11 parameters, one hidden layer with 20 neurons, and an output layer. The results indicate that the best forecasting performance for PM2.5 was demonstrated by the combination of the missForest imputation technique with the RPROP neural network, as assessed by the coefficient of determination (R2), mean absolute error (MAE), and root mean square error (RMSE). The proposed model is characterized by a low RMSE of 5.94 and a high R2 value of 0.88, demonstrating exceptional predictive performance in air quality.
Selective adsorption of single and binary dyestuffs by citrus peel: Characterization, and adsorption performance
(Elsevier Ltd, 2024) Şimşek, İsmail; Bahadır, Tolga; Çelebi, Hakan; Tulun, Şevket
The powdered citrus peel, which has been replaced with sodium hydroxide, was used in this study to test how well methylene blue and reactive black 5 dyestuff absorbed one or both. To find out about the texture and surface chemistry of modified citrus peel, Fourier transform infrared spectroscopy and scanning electron microscope analyses were carried out. Fourier transform infrared spectroscopy data revealed the presence of amphoteric radicals on the modified citrus peel surface, indicating the effective adsorption of methylene blue and reactive black 5. Many parameters affecting the batch adsorption process, such as modified citrus peel dose (0.1–0.5 g), pH (2–10), time (20–80 min), stirring speed (60–180 rpm), and temperature (20–45 °C), were studied. It is seen that the physical effect is at the forefront, homogeneous monolayer adsorption occurs, and the process fits the Langmuir and pseudo first order models for dyestuffs. Thermodynamic modeling showed that the adsorption of methylene blue and reactive black 5 was spontaneous and endothermic. At pH 2, an adsorption capacity of 0.67 mg/g and a removal efficiency of 66.86% were achieved for reactive black 5. For methylene blue at pH 6, the adsorption capacity was 4.34 mg/g, and the decolorization rate was 87%. The decreases in the removal rates of dyestuffs in the binary system indicate that they are affected by their simultaneous presence in the solution. The results proved that modified citrus peel can be useful for dyestuff removal in single or binary systems, although the removal capacity of modified citrus peel is highly dependent on methylene blue and reactive black 5
Surface defects due to bacterial residue on shrimp shell
(Elsevier B.V., 2024) Çelebi, Özgür; Bahadır, Tolga; Şimşek, İsmail; Aydın, Furkan; Kahve, Halil İbrahim; Tulun, Şevket; Büyük, Fatih; Çelebi, Hakan
The changes in the surface chemistry and morphological structure of chitin forms obtained from shrimp shells (Shp[sbnd]S) with and without microorganisms were evaluated. Total mesophilic aerobic bacteria (TMAB), estimated Pseudomonas spp. and Enterococcus spp. were counted in Shp-S by classical cultural counting on agar medium, where the counts were 6.56 ± 0.09, 6.30 ± 0.12, and 3.15 ± 0.03 CFU/g, respectively. Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM)/Energy dispersed X-ray (EDX) were used to assess the surface chemistry/functional groups and morphological structure for ChTfree (non-microorganism), and ChTmo (with microorganisms). ChTfree FTIR spectra presented a detailed chitin structure by O[sbnd]H, N[sbnd]H, and C[sbnd]O stretching vibrations, whereas specific peaks of chitin could not be detected in ChTmo. Major differences were also found in SEM analysis for ChTfree and ChTmo. ChTfree had a flat, prominent micropore, partially homogeneous structure, while ChTmo had a layered, heterogeneous, complex dense fibrous, and lost pores form. The degree of deacetylation was calculated for ChTfree and ChTmo according to FTIR and EDX data. The results suggest that the degree of deacetylation decreases in the presence of microorganisms, affecting the production of beneficial components negatively. The findings were also supported by the molecular docking model.
Temporal dynamics, meteorological effects, secondary organic aerosol estimation, and source identification of size-segregated carbonaceous aerosols
(John Wiley and Sons Inc, 2024) Tarhan, Burçak; Koçak, Ebru
During the period 2019–2020, size-segregated aerosol samples containing elemental and organic carbon (EC and OC) were investigated. These samples were collected weekly using an eight-stage cascade impactor from an urban site located at Aksaray University, Aksaray. The quantification of EC and OC was carried out through a thermal-optical transmission device. The results revealed consistent size distribution attributes of EC and OC between winter and summer. Although EC accounted for an insignificant percentage (4.4%) of particulate matter (PM) in the PM9.0–10.0 fraction during winter, a more substantial portion of OC in the same fraction (13.4%) comprised EC. Seasonal variations were distinct for EC but not significant for OC. Strong correlations between OC and EC were observed in coarse particle fractions, indicating a common source, with weaker correlations in fine particles. The highest OC/EC ratio was in the PM0.43–0.65 fraction, followed by PM2.1–3.3. The ratio of OC to EC in fine PM exceeded the threshold of 15 consistently. The observation indicates that as particle size increases, there is a noticeable decline in the OC to EC ratios. Secondary organic aerosols (SOA) accounted for 60.8% (winter) and 89.8% (summer) of OC values, emphasizing the substantial impact of SOA on Aksaray's atmosphere. Both seasons exhibited a multimodal distribution of ambient OC. In winter, the EC distribution was dominated by fine particles, with a bimodal pattern (PM1.1–2.1 and PM0.43–0.65 peaks). Common pollutant sources, including traffic emissions, road dust, biogenic emissions, and coal combustion, were identified for both seasons in coarse and fine particle fractions. These findings underscore the importance of emission control strategies targeting fine PM in Aksaray.
Characterization and evaluation of the anaerobic treatability of a dairy wastewater
(John Wiley and Sons Inc, 2024) Namal, Osman Önder; Altaş, Levent
In this study, the characteristics, anaerobic treatability, and energy potential of wastewater samples taken from a dairy products industry were investigated. It was determined that the wastewater has a high organic load (COD = 2800 mg O2/L) and a large proportion of this load is biodegradable. The biochemical methane potential (BMP) value of wastewater was measured as 1118.71 ± 122 ml CH4/L. Volatile solids (VS) removal of 67.25 ± 4.98% was achieved during batch tests and the obtained methane yield was calculated as 411.59 ± 22.8 ml CH4/g VS. Peak methane formation rate and lag time of microorganisms were determined as 163.42 ± 3.83 ml CH4/g VS d and 0.584 ± 0.023 d, respectively. Rate constant for the first-order kinetic model was 0.384 ± 0.072 d?1. The volatile fatty acid (VFA) yield was measured as 155.19 mg COD/g VSS. It was concluded that the wastewater can be treated anaerobically without any inhibition and it has great energy potential. Practitioner Points: Dairy wastewater has a large organic load and that most of the organics can be easily biodegradable. Although there are many components considered to be toxic for anaerobic treatment in wastewater, they were found to be very under the inhibition thresholds and did not pose any risk of toxicity. At a satisfactory level, organic matter removal and methane formation were observed in batch anaerobic tests. A rapid microbial adaptation was achieved and the system reached equilibrium in a short time without any acid accumulation. The electrical and caloric energy potentials of the obtained methane gas were calculated as 2.12 and 4.25 kWh/m3, respectively.

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