İsmail Tosun

Use of magnesit as a magnesium source for ammonium removal from leachate

Using magnesit (MgCO(3)) as a low cost source of magnesium ions in the struvite precipitation for the removal of high ammonium content of leachate was evaluated. Optimum molar concentration and pH conditions were analyzed to minimize the struvite solubility. Since solubility of magnesit in water is low, HCl was used to obtain soluble Mg. Maximum soluble Mg was obtained for the addition of 2 M HCl to the 1 M MgCO(3). Struvite precipitation with magnesit was effective for the removal of ammonium, suspended solid, phosphate and turbidity. Economical evaluation was made comparing the costs of two magnesium sources, MgCl(2) and MgCO(3). The economical analysis has shown that operation cost of struvite precipitation can be reduced about 18% by using MgCO(3) instead of MgCl(2). High salt concentration after struvite precipitation has no inhibitory effect on the anaerobic reactor performance.

Ammonium Removal from Aqueous Solutions by Clinoptilolite: Determination of Isotherm and Thermodynamic Parameters and Comparison of Kinetics by the Double Exponential Model and Conventional Kinetic Models

The adsorption isotherm, the adsorption kinetics, and the thermodynamic parameters of ammonium removal from aqueous solution by using clinoptilolite in aqueous solution was investigated in this study. Experimental data obtained from batch equilibrium tests have been analyzed by four two-parameter (Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich (D-R)) and four three-parameter (Redlich-Peterson (R-P), Sips, Toth and Khan) isotherm models. D-R and R-P isotherms were the models that best fitted to experimental data over the other two- and three-parameter models applied. The adsorption energy (E) from the D-R isotherm was found to be approximately 7 kJ/mol for the ammonium-clinoptilolite system, thereby indicating that ammonium is adsorbed on clinoptilolite by physisorption. Kinetic parameters were determined by analyzing the nth-order kinetic model, the modified second-order model and the double exponential model, and each model resulted in a coefficient of determination (R2) of above 0.989 with an average relative error lower than 5%. A Double Exponential Model (DEM) showed that the adsorption process develops in two stages as rapid and slow phase. Changes in standard free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) of ammonium-clinoptilolite system were estimated by using the thermodynamic equilibrium coefficients.

Co-composting kinetics of rose processing waste with OFMSW.

The objective of this study was to evaluate the kinetics of co-composting of rose processing waste (RPW) and organic fraction of municipal solid waste (OFMSW). Experimental data was obtained from 65-L batch reactors. Mixtures settled up with different ratios of RPW, OFMSW, inoculation, and bulking agent. The data was consisting of CO(2) evolution and inner temperature changing with time in the reactors. Decomposition process was evaluated based on rapidly and slowly biodegradable fractions of organic matter. The experimental data has been analyzed by kinetic models including the first-zero-order, first-first-order, Chen and Hashimotos and Levi-Minzis kinetic models using non-linear regression techniques. Kinetic parameters and rate constants were evaluated based on the average relative errors and coefficient of determination. The results of study showed that the best fitting kinetic model is the first-first-order.

Anaerobic Digestion and Methane Generation Potential of Rose Residue in Batch Reactors

Abstract In the study, anaerobic digestion of residues from rose oil industry was investigated by using a laboratory scale completely mixed batch reactor in volume of 10 L and 4 small reactors in volume of 400 mL. Ten liters reactor isolated with a water jacket and 0.4 L reactors settled into a water bath were operated at 35 ± 1°C. The study supplies biochemical methane potential of hydrolyzed and original residues. Experimental results showed that hydrolyzed rose residue produced a bit more methane than original residue. Methane production results were analyzed with first-order and Chen&Hashimotos models, and Chen&-Hashimotos model was found to be more suitable than first-order kinetic model.

Co-composting of two-phase olive-mill pomace and poultry manure with tomato harvest stalks

ABSTRACT In this study, two-phase olive-mill pomace with poultry manure and chopped tomato harvest stalks were composted at different initial carbon/nitrogen (C/N) ratios with fixed free air space of 35%. Composting experiment was carried out in the 15 aerobic reactors made of stainless steel and was monitored for 28 days. During the composting process, temperature, moisture content, organic matter (OM), pH, electrical conductivity, oxygen and carbon dioxide concentrations, total carbon, total nitrogen, ammonium nitrogen (), nitrate nitrogen (), and total phosphorus were monitored. Compost mass and volume changes were determined at the beginning, during remixings, and at the end of composting. While the stabilization period took less time for the mixtures containing a high amount of poultry manure, the mixtures having the high portion of two-phase olive-mill pomace took a longer time due to the structure of olive stone and its lignin content. Dry matter loss (range: 18.1–34.0%.) in the mixtures increased with an increase in the share of poultry manure and tomato stalks in the initial mixture. OM loss (range: 21.7–46.1%) for tomato stalks (measured separately) during composting increased due to an increase in the ratio of poultry manure in the initial mixtures. GRAPHICAL ABSTRACT

The effect of FAS and C/N ratios on co-composting of sewage sludge, dairy manure and tomato stalks

This study was conducted to determine the effects of C/N ratio and free air space in co-composting of sewage sludge with tomato stalk and dairy manure. Experiments were carried out in 100 L of stainless steel aerobic compost reactors with full automation system and monitored for 32 days. The temperature was controlled according to the Rutgers strategy. During the composting process, moisture content, organic matter content, pH, electrical conductivity, total carbon, total nitrogen, C/N ratio, total phosphorus, potassium, NH4+-N, NO3--N and heavy metals contents were determined. For evaluation of the stabilization process, organic matter, dry matter, ammonia and mass and volume losses and temperature index values were taken into consideration. The temperature pattern in the mixtures with dairy manure increased rapidly and reached higher levels depending on dairy manure ratio. The highest organic matter loss was 57.87%, which was in the mixture with a C/N ratio of 20 and a free air space ratio of 37%.