Biological nitrate removal in a laboratory-scale slow sand filter

This research evaluated removal of nitrates from drinking waters in a slow sand filter (SSF). Batch experiments were performed to determine optimum carbon to NO3-N (C/N) ratio for the filtration experiments. The filter column was filled with filter sand of an effective diameter of 0.5 mm and uniformity coefficient of 1.23. The filter was operated at filtration rates of between 0.02 to 0.120 m/h and 0.01 to 0.25 m/h with concentrations of 22.6 and 45.2 mg NO3-N/ℓ, respectively, and effluent samples of the SSF were taken at 6 depths of 10, 15, 20, 40, 60, 80 cm, and the bottom. Optimum C/N ratio was found to be 1.5 when using ethanol in batch tests when the removal efficiencies of NO3-N and C were higher than 90%. Although increasing filtration rates decreased NO3-N removal, effluent NO3-N concentration at the effluent port of the SSF was lower than the limit value. Most of the NO3-N removal was carried out at the upper layer of (10 cm) the filter bed. Concentration of NO3-N, NO2-N, and C were not detected at the 60 cm depth of the SSF through the study for the inlet concentrations of 22.6 mg NO3-N/ℓ. As expected, increasing influent NO3-N concentration to 45.2 mg/ℓ increased NO3-N, NO2-N, and C concentrations in the effluent water. The SSF process was unable to provide NO3-N removal rate of more than 228 g N/m3·d (0.2 m/h flow rate, 217g N/m2·d of surface loading rate). The NO3-N removal efficiency dropped slightly from 96 to 95% when the loading rate increased from 228 to 285 g/m3·d, but the effluent water contained higher concentrations of NO2-N (8.4 mg/ℓ) than the standard value. The results of the SSF experiment demonstrated that averaged nitrogen conversion to volatile solids was about 0.77 mg VS/mg NO3-N.Keywords: biodenitrification, slow sand filtration, drinking wate

Effect of Lipid Content on Anaerobic Digestion Process and Microbial Community: Review Study

The indiscriminate release of significant amounts of food waste, fat oil and grease, and sewage sludge (SS) into the environment causes severe contamination in many nations. There are numerous potential treatment methods to cope with the organic wastes, but anaerobic digestion is currently widely accepted to handle different kinds of biological waste. One of the pillars supporting anaerobic digester biogas production increase in treatment plants is the use of fats in the wastewaters. However, it has been claimed that high-fat wastes, particularly mono-digestion in the anaerobic reactor, inhibits acetoclastic and methanotrophic bacteria, delays the formation of gas even more, and overtaxes the system. This paper examines the research on the impact of lipids on biogas enhancement, reactor inhibition, impact on the microbial communities, and co-digestion with lipids in the anaerobic digestion process

Effect of Lipid Content on Anaerobic Digestion Process and Microbial Community: Review Study

The indiscriminate release of significant amounts of food waste, fat oil and grease, and sewage sludge (SS) into the environment causes severe contamination in many nations. There are numerous potential treatment methods to cope with the organic wastes, but anaerobic digestion is currently widely accepted to handle different kinds of biological waste. One of the pillars supporting anaerobic digester biogas production increase in treatment plants is the use of fats in the wastewaters. However, it has been claimed that high-fat wastes, particularly mono-digestion in the anaerobic reactor, inhibits acetoclastic and methanotrophic bacteria, delays the formation of gas even more, and overtaxes the system. This paper examines the research on the impact of lipids on biogas enhancement, reactor inhibition, impact on the microbial communities, and co-digestion with lipids in the anaerobic digestion process

EFFECT OF SALT CONTENT ON BIOGAS PRODUCTION AND MICROBIAL ACTIVITY: REVIEW STUDY

Over the years, biogas production technology has advanced with the goal of lowering process costs and greenhouse gas emissions, increasing biogas yield. Many design factors and operational aspects must be taken into account for steady and efficient biogas production. Furthermore, by properly monitoring various operational factors, the operation can be changed to unforeseen events. This review study covers the changes that occur when salt is present in biogas generation, as well as the impact on the microbial population. The results of the studies showed that adding salt in appropriate amounts is sufficient to enhance gas production and nutrient release, but the optimal scenario may differ from one biogas plant to another. Moreover, unfavorable situations to be avoided during the operation of the biogas plant have been discovered. Previous research had found that when the sodium salt concentration is less than 8 g/L, the reduction in methane generation is negligible. On the other hand, the addition of >8 g/L NaCl significantly reduced methane production (causing 17-80 percent inhibition)

Kinetic and isotherm study of cupper adsorption from aqueous solution using waste eggshell

The sorption of Cu2+ ions from aqueous solutions by eggshell was investigated in a batch experimental system with respect to the temperature, initial Cu2+ concentrations, pH, and biosorbent doses. The adsorption equilibrium was well described by the Langmuir isotherm model with the maximum adsorption capacity of 5.05 mg Cu2+/g eggshell at 25 °C. The value of qe increased with increasing the temperature while also increases the release of Ca2+ and HCO−3 ions from the eggshell. The highest sorption of Cu onto the waste eggshell was determined at the initial pH value of 4.0. The results confirming that the adsorption reaction of Cu2+ on the eggshell was thought to be endothermic. A comparison of the kinetic models such as pseudo first and second-order kinetics, intraparticle diffusion, and Elovich on the sorption rate demonstrated that the system was best described by the pseudo second-order kinetic model. First published online: 19 Mar 201

Evaluation of Alfalfa Plants Growth Irrigated with Arsenic Contaminated Water

The natural and anthropogenic process cause arsenic contamination of waters and creates serious environmental problems throughout the world. Due to the alfalfa is an important crop in diverse farming systems, it has been grown almost 33% of Turkey’s cropland. In this experimental study, effect of As on the alfalfa plant growth and As accumulation in the shoot of the alfalfa was determined. The accumulation of As in shoots as well as growth of alfalfa at various As contaminated water was evaluated. Alfalfa plants were grown in a greenhouse on a soil amended with different concentrations of As (control, 0.51.01.52.02.53.04.06.08.0 mg/L). In this study, data of two harvest samples were presented. Experimental results indicated that the irrigation with Ascontaminated water of alfalfa cause dry weight increase compared to control pots. As accumulation in the shoots of alfalfa plant increase with increasing As concentrations in the irrigation waters. As accumulation in the shoots at the 2 nd harvest samples were higher than the 1 st samples. However, As accumulation differences between the 1 st and 2 nd samples decreased when the As concentrations in the irrigation water was higher than 4 mg/L

"Belonging” in the gentrified Golden Horn/Halic neighbourhoods of Istanbul

Mainstream gentrification research predominantly examines experiences and motivations of the middle-class gentrifier groups, while overlooking experiences of non-gentrifying groups including the impact of in situ local processes on gentrification itself. In this paper, I discuss gentrification, neighbourhood belonging and spatial distribution of class in Istanbul by examining patterns of belonging both of gentrifiers and non-gentrifying groups in historic neighbourhoods of the Golden Horn/Halic. I use multiple correspondence analysis (MCA), a methodology rarely used in gentrification research, to explore social and symbolic borders between these two groups. I show how gentrification leads to spatial clustering by creating exclusionary practices and eroding social cohesion, and illuminate divisions that are inscribed into the physical space of the neighbourhood

The effect of petrochemical industry wastewater composition on the activated sludge microflora

In this study, the effect of wastewater composition on the activated sludge microflora has been evaluated. Wastewater samples from the aeration tank of a petrochemical industry wastewater treatment plant were taken and analyzed during a four-months period. The results of analysis indicate that the density of floc-forming, microorganims was higher than that of filamentous ones in the activated sludge tank, when sludge volume index (SVI) was lower than 150 ml/g. During the study, pH values of the mixed liquor were very high for fungal growth. Consequently, lower amounts of fungal species than floc-forming microorganisms were observed. Increasing, protozoan concentration in activated sludge process (ASP) caused lower amounts of suspended solids (SS), washed out especially at low dissolved oxygen (DO) concentration. Food/microorganisms (F/M) ratios were varying between 0.3-0.7 g BOD5/g mixed liqior suspended solids (MLSS) in the process. Even when influent wastewater contained low nitrogen and phosphorus levels, high BOD5 removal rates were observed, provided by filamentous microorganisms dominating in the unit. When the organic loading was higher than 14 g/m(3) /d, influent COD concentrations were higher than 2100 mg/L, and thus Pseudomonas spp. in the ASP were affected negatively

Assessment of the adsorption kinetics, equilibrium and thermodynamics for the potential removal of Ni²⁺ from aqueous solution using waste eggshell

In this study, Ni2+ sorption onto the waste eggshell was investigated under different operational conditions. Results indicated that the eggshell could be successfully used to remove Ni2+ ions from the water. Quick sorption process reached to equilibrium in about 2 hours with maximum sorption at pH 7.0. Based on the experimental data, Langmuir isotherm model with the qm value of 1.845 mg Ni2+/g eggshell was observed. The pseudo-second-order model provided the best correlation coefficient in comparison with other models. The calculated qe values derived from the pseudo-second-order for sorption of Ni2+ ions were very close to the experimental (qexp) values. Such thermodynamic parameters as ΔG°, ΔH°, and ΔS° were determined in order to predict the nature of adsorption. Results indicated that the adsorption of Ni2+ onto the eggshell was endothermically supported by the increasing adsorption of Ni2+ ions with temperature

Evaluation of Alfalfa Plants Growth Irrigated with Arsenic Contaminated Water

The natural and anthropogenic process cause arsenic contamination of waters and creates serious environmental problems throughout the world. Due to the alfalfa is an important crop in diverse farming systems, it has been grown almost 33% of Turkey’s cropland. In this experimental study, effect of As on the alfalfa plant growth and As accumulation in the shoot of the alfalfa was determined. The accumulation of As in shoots as well as growth of alfalfa at various As contaminated water was evaluated. Alfalfa plants were grown in a greenhouse on a soil amended with different concentrations of As (control, 0.51.01.52.02.53.04.06.08.0 mg/L). In this study, data of two harvest samples were presented. Experimental results indicated that the irrigation with Ascontaminated water of alfalfa cause dry weight increase compared to control pots. As accumulation in the shoots of alfalfa plant increase with increasing As concentrations in the irrigation waters. As accumulation in the shoots at the 2 nd harvest samples were higher than the 1 st samples. However, As accumulation differences between the 1 st and 2 nd samples decreased when the As concentrations in the irrigation water was higher than 4 mg/L