Estimation of total sediment load concentration obtained by experimental study using artificial neural networks

Estimation of sediment concentration in rivers is very important for water resources projects planning and managements. The sediment concentration is generally determined from the direct measurement of sediment concentration of river or from sediment transport equations. Direct measurement is very expensive and cannot be conducted for all river gauge stations. However, sediment transport equations do not agree with each other and require many detailed data on the flow and sediment characteristics. The main purpose of the study is to establish an effective model which includes nonlinear relations between dependent (total sediment load concentration) and independent (bed slope, flow discharge, and sediment particle size) variables. In the present study, by performing 60 experiments for various independent data, dependent variables were obtained, because of the complexity of the phenomena, as a soft computing method artificial neural networks (ANNs) which is the powerful tool for input–output mapping is used. However, ANN model was compared with total sediment transport equations. The results show that ANN model is found to be significantly superior to total sediment transport equations.     

Formulation of a soil-pesticide transport model based on a compartmental approach

A semianalytical soil-pesticide transport model is formulated based on a compartmental approach to determine spatial and temporal variations of pesticide residues across a soil profile. The compartmental model is implemented by drawing an analogy between a series of continuous-flow stirred tank reactors and a soil horizon that consists of multiple perfectly mixed compartments. The analogy is strengthened by exploiting a relation between the compartment series and the conventional convective-dispersive equation (CDE) for vertical transport in the soil. Consequently, the number of compartments in the model formulation is not free, but dictated as a function of transport parameters. The model formulation allows consideration of arbitrary boundary value specifications and also, for some cases, spatially varying initial concentration profiles. Sorption kinetics is represented via a two-site model that involves a linear sorption isotherm and a first-order irreversible sorption or a radial diffusive penetrating model. For these three cases, analysis of the compartmental model allows the resultant concentration profiles to be expressed in terms of the Poisson distribution. When a nonlinear kinetic sorption model is used to simulate the sorption processes, an analytical solution is not found and a numerical approach is required.     

Incinerating volatile organic compounds with ferrospinel catalyst MnFe2O4: an example with isopropyl alcohol

This paper concerns the incineration of isopropyl alcohol (IPA) using the ferrospinel catalyst MnFe2O4. It covers the preparation of the ferrospinel catalyst, the screening of catalytic activity, catalytic incineration testing, and 72-hr decay testing of the catalyst. The experimental results of catalyst screening reveal that the Mn/Fe catalyst is the best of five prepared catalysts (chromium/iron [Cr/Fe], manganese/iron [Mn/Fe], zinc/iron [Zn/Fe], nickel/iron [Ni/Fe], and pure magnetite [Fe3O4]). In tests of the catalytic incineration system used to convert IPA, 98% conversion was obtained at a space velocity of 24,000 hr(-1), an oxygen (O2) content of 21%, 1700 ppm of IPA, and a reaction temperature of 200 degrees C.     

Optimization of a wet scrubber with electrolyzed water spray—Part II: Airborne culturable bacteria removal

Airborne microorganisms, especially the pathogenic microorganisms, emitted from animal feeding operations (AFOs) may harm the environment and public health and threaten the biosecurity of the farm and surrounding environment. Electrolyzed water (EW), which was considered to be an environmentally friendly disinfectant, may be a potential spraying medium of wet scrubber for airborne microorganism emission reduction. A laboratory test was conducted to investigate the airborne bacteria (CB) removal efficiency of the wet scrubber by EW spray with different designs and operating parameters. Both the available choline (AC) initial loss rate and AC traveling loss rate of acidic electrolyzed water (AEW; pH = 1.35) were much higher than those of slightly acidic electrolyzed water (SAEW; pH = 5.50). Using one spraying stage with 4 m sec^?1 air speed in the duct, the no detect lines (NDLs) of SAEW (pH = 5.50) for airborne Escherichia coli, Staphylococcus aureus, and Salmonella enteritidis removal were all 50 mg L^?1, whereas the NDLs of AEW (pH = 1.35) for airborne E. coli, S. aureus, and S. enteritidis removal increased to 70, 90, and 90 mg L^?1, respectively. The NDLs of SAEW (pH = 5.50) for airborne E. coli, S. aureus, and S. enteritidis were lower than those of AEW (pH = 1.35) at single spraying stage. Increase in the number of stages lowered the NDLs of both SAEW (pH = 5.50) and AEW (pH = 1.35) for airborne E. coli, S. aureus, and S. enteritidis. EW with a higher available chlorine concentration (ACC) was needed at air speed of 6 m sec^?1 to reach the same airborne CB removal efficiency as that at air speed of 4 m sec^?1. The results of this study demonstrated that EW spray wet scrubbers could be a very effective and feasible airborne CB mitigation technology for AFOs.

Implications: It is difficult to effectively reduce airborne bacteria emitted from animal feeding operations (AFOs). Electrolyzed water (EW) with disinfection effect and acidity is a potential absorbent for spray in wet scrubber to remove microorganisms and ammonia. Based on the field test results, a laboratory experiment we conducted this time was to optimize the design and operation parameters to improve the airborne bacteria removal efficiency. A better understanding of the EW application in the wet scrubber can contribute to the mitigation of airborne bacteria from animal houses and improve the atmosphere air quality.     

A study on the Cr(VI) removal from aqueous solutions by steel wool

The reduction of Cr(VI) by steel wool and the precipitation of reduced chromium by CaCO(3) powder and NaOH solution were investigated in continuous and batch systems, respectively. The effects of acid and initial Cr(VI) concentrations, volumetric rate and temperature of solution on Cr(VI) reduction were studied. The results showed that the reduction of Cr(VI), to a large extent, depended on, and increased with, acid concentration. The Cr(III) and iron ions in the reduced solution were completely precipitated by using NaOH solution at appropriate alkaline conditions. It was concluded that CaCO(3) powder could be used as a cheap precipitant for Cr(III) ions. But the iron ions in the reduced solution could not be fully removed by using this precipitant.     

颗粒层除尘器冷态压力损失的研究

本文采用了工业颗粒层除尘器最常用的石英砂滤料进行了固定床压损冷态实验,实验与理论研究结果表明压损与过滤风速呈线性关系,并且服从达西定律,由实验数据得出石英砂滤料的压损系数ξ=1190,线性相关系数r=0.973.所得出的冷态压损计算公式可用于颗粒层厚度设计,同时也为确定过滤风速和反洗清灰动力提供了依据.     

Heavy Metal Levels in Biota and Sediments in the Northern Coast of the Marmara Sea

Concentration of Cd, Co, Cr, Ni, Zn, Fe, Mn, Pb and Cu were determinedin biota and sediment samples collected from the Marmara Sea in Turkey. The levels of Zn, Fe, Mn, Pb and Cu in the macroalgae are higher than previous studies in the Marmara Sea. Moreover, Cu and Zn concentrations at the present study are significantly high than Bosphorus and Black Sea algae. The order heavy metal concentrations in the mussel samples was: Fe > Zn > Ni > Mn > Cu > Pb > Cr > Cd > Co. The metal concentrations are generally lower when compared with the Black Sea mussels except Pb. At the same time, concentrations of Pb, Cu and Zn in the mussel species are lower when compared with the results in the Aegean Sea. The ranges of Mn and Cu in the tested fish samples are higher than Black Sea fish. On the other hand, Cd, Co, Cr, Zn and Pb concentrations are lower. The northern coast of the Marmara Sea having the highest metal concentrations in sediments as follows: Co, Cr, Ni, Fe at ?arköy ; Pb, Cu at M. Ere?li; Cd, Zn, Mn at Menek?e. The heavy metal levels in the sediment samples are lower than other areas in the Marmara Sea.     

SO2 modeling in İzmit Gulf, Turkey during the winter of 1997: 3 cases

In this study, SO₂ dispersion over İzmit Gulf is simulated by California Puff (CALPUFF) model for three air pollution cases, which occurred on January 28, February 12, and February 26, 1997. These days are generally characterized by dominant high-pressure systems – pressure values reaching 1032 mb, low wind speeds and sometimes calm conditions, and low temperatures with a minimum of 0°C. Hourly simulations during those critical cases were carried out and results revealed very high concentrations of SO₂ transported to the downwind regions of Tüpraş and Gebze, and values sometimes exceeded 1,000 μg/m³. Nighttime and morning simulations associated with inversion produced considerably higher values of SO₂ than the afternoon simulations associated with breeze. Model verification was conducted by comparing the measured daily average values of eight stations with the model predicted values at the same receptor points. Results showed that the model well predicted the values at station Gebze in all three cases. The model sometimes underestimated and sometimes overestimated the concentrations at other receptor stations.     

Correction to: Sustainable development goals assessment of Erzurum province with SWOT‑AHP analysis

Environment, Development and Sustainability -