Design of Low-Cost Ethanol Production Medium From Syngas: An Optimization of Trace Metals for Clostridium Ljungdahlii

[Abstract] Syngas fermentation via the Wood-Ljungdahl (WL) pathway is a promising approach for converting gaseous pollutants (CO and CO2) into high-value commodities. Because the WL involves several enzymes with trace metal components, it requires an adequate supply of micronutrients in the fermentation medium for targeted bioprocessing such as bioethanol production. Plackett-Burman statistical analysis was performed to examine the most efficient trace elements (Ni, Mg, Ca, Mn, Co, Cu, B, W, Zn, Fe, and Mo) and their concentrations for Clostridium ljungdahlii on ethanol production. Overall, 1.5 to 2.5 fold improvement in ethanol production could be achieved with designed trace element concentrations. The effects of tungsten and copper on ethanol and biomass production were determined to be the most significant, respectively. The model developed was statistically significant and has the potential to significantly decrease the cost of trace element solutions by 18–22%. This research demonstrates the critical importance of optimizing the medium for syngas fermentation in terms of product distribution and economic feasibility.Turquía. Scientific and Technological Research Council of Turkey; 118Y305Turquía. Ege University; FDK-2020-22039Xunta de Galicia; ED481D 2019/03

Evaluation of Performance of Sequential Membranes Used in Pilot Scale Biogas Plant: A Case Study for Laying Hen Manure

Poultry sector is a very important business activity in all over the Europe, especialy in Turkey and accordingly there is significant amount of waste disposal problem. One of the environmental assesment options for the use of this waste is environmentally friendly biofuel production such as biomethane. High nitrogen content is one of the important challenges to transform chicken manure to biofuel. For this reason, significant amount of dilution water is required in the systems using manure as mono substrate and thereby very large storage volumes (storage time 4-6 months) are needed for the enormous amount of effluent after anaerobic digestion process. These two subjects are threatening the economic viability of the biogas production. Furthermore, need for dilution water is an economic burden to the businesses in countries where the water scarcity is a serious concern. On the other hand, integrated use of membrane system offers possibility of using the digestion effluent as dilution water over and over where nitrogen is removed selectively by membrane assisted biogas reactor configuration. In this way, significant economy could be provided in the overall project budget by eliminating the final storage needs as well as water saving. For this purpose, the performance results of a pilot plant scale membrane system consisting of micro (MF), ultra (UF), nano (NF) and reverse osmosis (RO) membranes are presented in this study to be used in real scale applications. The feasibility of continuous reuse of digestate as fresh feed water was suggested. For this purpose, NF90 and X20 type membranes were found to be most effective ones for the recovery of ammonium (88% and 98%) from the digestate

Separation of 1,3-Propanediol by Nanofiltration Method

The application potential of nanofiltration (NF) method on the separation of 1,3-propanediol (1,3-PDO) from synthetically prepared fermentation broth was investigated. The rejection tests at different pressures (10, 20, 30 bar) and pH values (7 and 10) were performed on laboratory scale using Desal DL-5 NF membrane. The rejection of succinic acid, having the molecular weight larger than or closer to the molecular weight cut-offs (MWCOs) of Desal-5 DL NF membrane was 100% independent of operating pressure and pH. The results of this study clearly showed that NF process is a very promising pretreatment step for the removal of volatile organic acids from the fermentation broth

Decolorisation of textile effluent using homogeneous photochemical oxidation processes

In this paper, the results of COD and colour removal from textile effluent using homogeneous photochemical oxidation processes in a batch mode are presented. The results show that the best result was obtained using a combined O-3/H2O2/UV process, with 97% removal for COD and 99% removal for colour. Optimum conditions for pH and hydrogen peroxide dosage for this process was determined as 3 and 25 mg/l, respectively. Both H2O2/UV and O-3/UV combinations were found to result in similar levels of COD and colour removal efficiencies (over 91% removal for COD and 96% for colour). In addition, the associated operating costs of the various advanced oxidation processes were determined in this study

Feasibility of physico-chemical treatment and Advanced Oxidation Processes (AOPs) as a means of pretreatment of olive mill effluent (OME)

The efficiency of alternative pretreatment methods for an olive mill effluent (OME) in producing a final effluent conforming to Turkish Water Pollution Standards for discharge into the public sewage was studied. For this purpose, various treatment alternatives such as acid cracking, chemical coagulation, adsorption and Advanced Oxidation Processes (AOPs) were studied. A significant amount of Chemical Oxygen Demand (COD), total phenol and oil and grease removal were obtained by acid cracking followed by chemical coagulation either using alum or iron chloride salts. Among the alternative chemicals, both Al2SO4 and FeCl3 resulted in the same COD and total phenol removal efficiency in this study (94-95% COD removal and 90-91% total phenol removals). Both H2O2/UV and O-3/UV combinations studied in this paper were found to give practically same COD and total phenol removal efficiencies (over a 99% removal for both COD and total phenol). (c) 2004 Elsevier Ltd. All rights reserved

Comparison of various advanced oxidation processes and chemical treatment methods for COD and color removal from a polyester and acetate fiber dyeing effluent

In this paper, a comparison of various advanced oxidation processes (O-3, O-3/UV, H2O2/UV, O-3/H2O2/UV, Fe2+/H2O2) and chemical treatment methods using Al-2(SO4)(3)(.)18H(2)O, FeCl3 and FeSO4 for the chemical oxygen demand (COD) and color removal from a polyester and acetate fiber dyeing effluent is undertaken. Advanced oxidation processes (AOPs) showed a superior performance compared to conventional chemical treatment, which maximum achievable color and COD removal for the textile effluent used in this study was 50% and 60%, respectively. Although O-3/H2O2/UV combination among other AOPs methods studied in this paper was found to give the best result (99% removal for COD and 96% removal for color), use of Fe2+/H2O2 seems to show a satisfactory COD and color removal performance and to be economically more viable choice for the acetate and polyester fiber dyeing effluent on the basis of 90% removal. (C) 2003 Elsevier Ltd. All rights reserved

Comparative evaluation of a laboratory and full-scale treatment alternatives for the vegetable oil refining industry wastewater (VORW)

The efficiency of alternative treatment processes in producing a final effluent conforming to regulatory standards with regards to chemical oxygen demand (COD) and oil and grease (O&G) loads was assessed. The study was conducted in three principal stages: waste characterization, lab-scale treatability studies and full-scale applications. The effluent were characterized in terms of pH (6.3-7.2), total COD (13,750-15,000 mg l(-1)), soluble COD (CODs) (6500-7000 mg l(-1)), biochemical oxygen demand (BOD5) (4300-4700 mg l(-1)), O&G (3600-3900 mg l(-1)), total suspended solids (TSS) (3800-4130 mg l(-1)), total Kjeldahl nitrogen (TKN) (636-738 mg l(-1)) and total phosphorus (TP) (61-63 mg l(-1)). After analyzing various raw effluent parameters, lab-scale chemical treatability studies were conducted using Al-2(SO4)(3).18H(2)O and FeCl3.6H(2)O. The results showed 88 and 84% influent COD reduction, while O&G removal was 81 and 93%, respectively. The removal of total suspended solids (TSS) varied from 78 to 86%. Lab-scale aerobic biological treatment reactors with a HRT of 24 h and food to microorganism ratio of 0.3-0.5 were also run to assess the process efficiency and determine the residual soluble COD in the effluent. Residual soluble COD was 59-70 mg l(-1). Based on the results from waste characterization and treatability studies, a continuous full-scale treatment system was constructed and operated in two vegetable oil refining plants with a different pretreatment flow scheme. The overall percentage removal of COD, TSS, and O&G was 92-96, 83-98 and 93-95%, respectively