Prediction of COD in industrial wastewater treatment plant using an artificial neural network.

In this investigation, the modeling of the Aksaray industrial wastewater treatment plant was performed using artificial neural networks with various architectures in the MATLAB software. The dataset utilized in this study was collected from the Aksaray wastewater treatment plant over a 9-month period through daily records. The treatment efficiency of the plants was assessed based on the output values of chemical oxygen demand (COD) output. Principal component analysis (PCA) was applied to furnish input for the Feedforward Backpropagation Artificial Neural Networks (FFBANN). The model's performance was evaluated using the Mean Squared Error (MSE), the Mean Absolute Error (MAE) and correlation coefficient (R2) parameters. The optimal architecture for the neural network model was determined through several trial and error iterations. According to the modeling results, the ANN exhibited a high predictive capability for plant performance, with an R2 reaching up to 0.9997 when comparing the observed and predicted output variables.

The impact of curfews on emergency departments and orthopedic traumas.

BACKGROUND: The aim of our study was to investigate the impact of curfews imposed due to the COVID-19 pandemic on emergency department visits, orthopedic trauma frequencies, and types of trauma. METHODS: In this single-center, retrospective cohort study, a total of 16,242 patients, including 3,020 trauma patients, were admitted to level 1 trauma center emergency department between April-June 2020 and 2021 (curfew group) and between April-June 2018 and 2019 (control group). Patients were separated according to emergency department triage categories and trauma mechanisms, and the changes in the days of curfew were analyzed. RESULTS: With the curfews, there was a 54% decrease in emergency room admissions. This decrease was seen especially in yellow and green area patients, whereas there was no significant decrease in red area patients with the highest urgency. When the effect of curfews on orthopedic traumas was analyzed, a 20% decrease was observed in trauma cases. In particular, there was a significant decrease in traffic accidents in and out of the vehicle, assault, and sports injuries, whereas there was no significant decrease in falls from the same level, motor accidents, and occupational accidents. CONCLUSION: The impact of curfews on the density of emergency departments and trauma patients will guide the health management policies to be followed in future curfews to be implemented for different reasons. In the light of this information, more effective resource management and better quality health service planning will be ensured.

Adsorption capability of brewed tea waste in waters containing toxic lead(II), cadmium (II), nickel (II), and zinc(II) heavy metal ions.

Recently, the search for low-cost eco-friendly adsorbents has become one of the main objectives of researchers. The aim of this study was to test the removal of four heavy metals, namely lead (Pb), zinc (Zn), nickel (Ni) and cadmium (Cd), from a simulated watery solution using brewed tea waste as a potentially suitable adsorbent. The effects of pH levels (2.0-6.0), adsorbent amount (0.1-5.0 g), contact times (1-150 min.) were examined throughout the adsorption process. The results of the experiments showed that the heavy metals elimination yields had an inverse relationship with pH and a linear relationship between the other parameters. The optimum pH for the removal of the heavy metals was between 4.0 and 5.0 in the case of the brewed tea waste. Equilibrium times of 2, 10, 30 and 5 min were required for the adsorption of Pb, Zn, Ni, Cd onto Camellia sinensis, respectively. Based on the results of this study it can be said that brewed tea waste has a high potential to remove heavy metals from aqueous solutions. The maximum adsorption capacities were calculated as 1.197, 1.457, 1.163 and 2.468 mg/g, for Pb, Zn, Ni and Cd, respectively, by fitting the equilibrium data to the Langmuir isotherm model.

Hydrocarbon degradation abilities of psychrotolerant Bacillus strains.

Biodegradation requires identification of hydrocarbon degrading microbes and the investigation of psychrotolerant hydrocarbon degrading microbes is essential for successful biodegradation in cold seawater. In the present study, a total of 597 Bacillus isolates were screened to select psychrotolerant strains and 134 isolates were established as psychrotolerant on the basis of their ability to grow at 7 °C. Hydrocarbon degradation capacities of these 134 psychrotolerant isolate were initially investigated on agar medium containing different hydrocarbons (naphthalene, n-hexadecane, mineral oil) and 47 positive isolates were grown in broth medium containing hydrocarbons at 20 °C under static culture. Bacterial growth was estimated in terms of viable cell count (cfu ml-1). Isolates showing the best growth in static culture were further grown in presence of crude oil under shaking culture and viable cell count was observed between 8.3 × 105-7.4 × 108 cfu ml-1. In the final step, polycyclic aromatic hydrocarbon (PAH) (chrysene and naphthalene) degradation yield of two most potent isolates was determined by GC-MS along with the measurement of pH, biomass and emulsification activities. Results showed that isolates Ege B.6.2i and Ege B.1.4Ka have shown 60% and 36% chrysene degradation yield, respectively, while 33% and 55% naphthalene degradation yield, respectively, with emulsification activities ranges between 33-50%. These isolates can be used to remove hydrocarbon contamination from different environments, particularly in cold regions.

Removals of non-analogous OTC and BaP in AMCBR with and without primary substrate.

Anaerobic biodegradation of mixed non-analogous two substrates was studied in a binary system with and without the primary substrate using an anaerobic multichamber bed (AMCBR). In the binary mixture, the biodegradation of less-degradable oxytetracycline (OTC) was restarted in the presence of more degradable benzo[a]pyrene (BaP) in the initial runs of the AMCBR, but enhanced biodegradation of the more recalcitrant OTC occurs in the later runs of the AMCBR due to enhanced biomass growth on dual substrates without the primary carbon source. The biodegradation yields of the OTC, BaP were discussed with sole-substrate systems and with the dual substrate system in the presence of the primary substrate. The maximum OTC and BaP yields were 93% in Run 3 with the primary substrate, while the maximum BaP and OTC yields were 95%, 98% in Run 3 without the primary substrate. A dual form of the Monod was found to adequately predict the substrate interactions in the binary mixture of OTC and BaP using only the parameters derived from batch experiments. At low BaP (4 mg L(-1)) and OTC (40 mg L(-1)) concentrations, a non-competitive inhibition does not affect the binding of the substrate and so the K(s) were was not affected while the µ(max) was lowered. At high BaP (10 mg L(-1)) and OTC (100 mg L(-1)) concentrations, the BaP and OTC were biodegraded according to competitive inhibition with increased K(s) while µ(max) was not affected. BaP and OTC were biodegraded according to Haldane at high concentrations (>10 mg L(-1) for BaP, 100 mg L(-1) OTC) where they were used as the sole substrate.

Effects of sludge retention time (SRT) and biosurfactant on the removal of polyaromatic compounds and toxicity.

A laboratory-scale aerobic activated sludge reactor (AASR) system was employed to investigate the effects of SRT on the removal of three less hydrophobic and six more hydrophobic PAHs in the presence of rhamnolipid (RD), emulsan (EM) and surfactine (SR) biosurfactants. Among the biosurfactants it was found that RD exhibits a better performance than the others in the removal of PAHs. At a RD of 15 mg l(-1) aerobic treatment for 25 days SRT was enough to remove over 90% of the total PAHs, 88% of the COD originating from the inert organics (COD(inert)) and 93% of the COD originating from the inert soluble microbial products (COD(imp)). At this SRT and RD concentration, about 96-98% of the RD was biodegraded by the AASR system, 1.2-1.4% was accumulated in the system, 1.1-1.3% was released in the effluent, and 1.2-1.4% remained in the waste sludge. The addition of electron acceptors (NO(3)(-1), SO(4)(-2)) and increasing of temperature up to 45°C enhanced the PAH yields. The most effective PAH degradation occurred in high-oxygenated and neutral pH conditions. The PAH concentration affecting half of the Daphnia magna organism (EC(50) value) was reduced from EC(50)=45.02 ng ml(-1) to the PAH concentration affecting only 6% of the live Daphnia magna (EC(6)=5.30 ng ml(-1)) at the end of the aerobic treatment at a SRT of 25 days. Toxicity removals originating from the PAHs were 96%.

Effect of rhamnolipid on the aerobic removal of polyaromatic hydrocarbons (PAHs) and COD components from petrochemical wastewater.

The removal efficiencies of 15 PAHs and some COD components (inert, readily degradable, slowly degradable and metabolic products) from a wastewater taken from a petrochemical industry treatment plant (Izmir, Turkey) have been determined using an aerobic completely stirred tank reactor (CSTR). Addition of rhamnolipid surfactant (15 mg l(-1)) increased the removal efficiencies of PAHs and soluble COD from 72% and 90% to 80% and 99%, respectively. The rhamnolipid treatment caused a significant increase of 5- and 6-ring PAH degradation. The soluble COD removal efficiency was 93%, in CSTR reactors with rhamnolipid added. The inert COD removal efficiency was 60% in a CSTR reactor containing rhamnolipid. Batch tests showed that removal arising from the adsorption of the PAHs was low (between 1.88% and 4.84%) while the removal of PAHs from the petrochemical industry wastewater via volatilization varied between 0.69% and 5.92%. Low sorption capacity (K(p)) values for refinery activated sludge (approximately 2.98 l g(-1)) confirmed that bio-sorption was not an important mechanism controlling the fate of PAHs in aerobic CSTR reactors. Models proposed to simulate the PAH removal indicated that 94% of the PAHs were removed via biodegradation.