scholarly journals Multiple Effects of Different Nickel Concentrations on the Stability of Anaerobic Digestion of Molasses

2021 ◽  
Vol 13 (9) ◽  
pp. 4971
Author(s):  
Sohail Khan ◽  
Fuzhi Lu ◽  
Muhammad Kashif ◽  
Peihong Shen

Molasses is a highly thick by-product produced after sugarcane crystallization constitutes large amounts of biodegradable organics. These organic compounds can be converted to renewable products through anaerobic digestion. Nevertheless, its anaerobic digestion is limited due to its high chemical oxygen demand (COD) and ion concentration. The effects of nickel (Ni2+) on the stability of anaerobic digestion of molasses were established by studying the degradation of organic matter (COD removal rate), biogas yield, methane content in the biogas, pH, and alkalinity. The results showed that there were no significant effects on the stability of pH and alkalinity. Increased COD removal rate and higher methane content was observed by 2–3% in the digesters receiving 2 and 4 mg/L of Ni2+ in the first phase of the experiment. Ni2+ supplemented to reactors at concentration 2 mg/L enhanced biogas yield. Overall, it is suggested that the addition of Ni2+ has some effects on the enhancement of biogas yield and methane contents but has no obvious effects on the long-lasting stability of the molasses digestion.

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2392 ◽  
Author(s):  
Marcin Dębowski ◽  
Marcin Zieliński ◽  
Marta Kisielewska ◽  
Joanna Kazimierowicz

The aim of this study was the performance evaluation of anaerobic digestion of dairy wastewater in a multi-section horizontal flow reactor (HFAR) equipped with microwave and ultrasonic generators to stimulate biochemical processes. The effects of increasing organic loading rate (OLR) ranging from 1.0 g chemical oxygen demand (COD)/L·d to 4.0 g COD/L·d on treatment performance, biogas production, and percentage of methane yield were determined. The highest organic compounds removals (about 85% as COD and total organic carbon—TOC) were obtained at OLR of 1.0–2.0 g COD/L·d. The highest biogas yield of 0.33 ± 0.03 L/g COD removed and methane content in biogas of 68.1 ± 5.8% were recorded at OLR of 1.0 g COD/L·d, while at OLR of 2.0 g COD/L·d it was 0.31 ± 0.02 L/COD removed and 66.3 ± 5.7%, respectively. Increasing of the OLR led to a reduction in biogas productivity as well as a decrease in methane content in biogas. The best technological effects were recorded in series with an operating mode of ultrasonic generators of 2 min work/28 min break. More intensive sonication reduced the efficiency of anaerobic digestion of dairy wastewater as well as biogas production. A low nutrient removal efficiency was observed in all tested series of the experiment, which ranged from 2.04 ± 0.38 to 4.59 ± 0.68% for phosphorus and from 9.67 ± 3.36 to 20.36 ± 0.32% for nitrogen. The effects obtained in the study (referring to the efficiency of wastewater treatment, biogas production, as well as to the results of economic analysis) proved that the HFAR can be competitive to existing industrial technologies for food wastewater treatment.


2013 ◽  
Vol 68 (1) ◽  
pp. 257-260 ◽  
Author(s):  
Yujie Feng ◽  
Junfeng Liu ◽  
Limin Zhu ◽  
Jinzhi Wei

The clomazone herbicide wastewater was treated using a combined technology composed of electrochemical catalytic oxidation and biological contact degradation. A new type of electrochemical reactor was fabricated and a Ti/SnO2 electrode was chosen as the anode in electrochemical-oxidation reactor and stainless steel as the cathode. Ceramic rings loaded with SnO2 were used as three-dimensional electrodes forming a packed bed. The operation parameters that might influence the degradation of organic contaminants in the clomazone wastewater were optimized. When the cell voltage was set at 30 V and the volume of particle electrodes was designed as two-thirds of the volume of the total reactor bed, the chemical oxygen demand (COD) removal rate could reach 82% after 120 min electrolysis, and the ratio of biochemical oxygen demand (BOD)/COD of wastewater increased from 0.12 to 0.38. After 12 h degradation with biological contact oxidation, the total COD removal rate of the combined technology reached 95%, and effluent COD was below 120 mg/L. The results demonstrated that this electrocatalytic oxidation method can be used as a pretreatment for refractory organic wastewater before biological treatment.


Archaea ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Shuo Wang ◽  
Jianzheng Li ◽  
Guochen Zheng ◽  
Guocheng Du ◽  
Ji Li

Hydrogen-producing acetogens (HPA) have a transitional role in anaerobic wastewater treatment. Thus, bioaugmentation with HPA cultures can enhance the chemical oxygen demand (COD) removal efficiency and CH4yield of anaerobic wastewater treatment. Cultures with high degradation capacities for propionic acid and butyric acid were obtained through continuous subculture in enrichment medium and were designated as Z08 and Z12. Bioaugmentation with Z08 and Z12 increased CH4production by glucose removal to 1.58. Bioaugmentation with Z08 and Z12 increased the COD removal rate in molasses wastewater from 71.60% to 85.84%. The specific H2and CH4yields from COD removal increased by factors of 1.54 and 1.63, respectively. Results show that bioaugmentation with HPA-dominated cultures can improve CH4production from COD removal. Furthermore, hydrogen-producing acetogenesis was identified as the rate-limiting step in anaerobic wastewater treatment.


2020 ◽  
Author(s):  
Sohail Khan ◽  
Fuzhi Lu ◽  
Qiong Jiang ◽  
Chengjian Jiang ◽  
Muhammad Kashif ◽  
...  

Abstract Background Molasses is a highly dense and refined byproduct produced in the sugarcane industry, and it contains high amounts of degradable compounds. These compounds can potentially be converted into renewable products biologically. However, the involved biological process is negatively influenced by the high chemical oxygen demand (COD) of molasses and its high ion concentration, although this problem is commonly addressed by dilutions. Results The co-digestion of molasses with rice alcohol waste water (RAW) was compared with its mono-digestion at an increasing organic loading rate (OLR). Both processes were assessed by detecting the COD removal rate, the methane contents of biogas, and the structure and composition of microbial communities at different stages. Results showed that the co-digestion is stable up to a maximum OLR of 16 g COD L− 1d− 1. By contrast, after the acclimatization phase, the mono-digestion process was upset twice, which occurred at a maximum OLR of 9 and 10 g COD L− 1d− 1. The co-digestion procgess demonstrated consistency in terms of COD removal rates (86.36% ± 0.99–90.72% ± 0.63%) and methane contents (58.10% ± 1.12–64.47% ± 0.59%) compared with the mono-digestion process. Microbial community analysis showed that the relative abundance of bacterial and archaeal communities differs between the processes at different stages. However, in both processes, Propionibacteriaceae was the most abundant family in the bacterial communities, whereas Methanosaetaceae was abundant in the archaeal communities. Conclusion Rice alcohol wastewater could be a good co-substrate for anaerobic digestion of molasses. Integrate molasses into progressive biogas production at high OLR.


2001 ◽  
Vol 43 (11) ◽  
pp. 51-58 ◽  
Author(s):  
P. C. Male ◽  
W. A. Pretoruis

Wastewater high in phenolic content (948 mg/l) and dissolved solids (5.4 g/l) had to be treated to remove most of the organic material and toxic compounds. A laboratory scale High Pressure (3 bar) Bioreactor (HPB) was developed and operated to treat the wastewater using a ceramic ultra filtration membrane as biomass separator. The performance of the system was compared to a normal activated sludge plant (ASP) using sludge settling for separation. The HPB was more stable than the ASP, which twice became unstable with a resulting biomass loss. Both reactors removed 90% of the chemical oxygen demand (COD) loading, reducing the phenol concentration below 20 mg/l. The maximum COD removal rate of the HPB was 28 kg/m3.d compared to 15 kg/m3.d of the ASP, while the HPB achieved 16-32 times better oxygen transfer than the ASP. It was concluded that the HPB was the preferred treatment system compared to the ASP, when treating high strength inhibitory wastewaters, due to its stable operating performance and high COD removal rate.


1993 ◽  
Vol 28 (3) ◽  
pp. 597-620 ◽  
Author(s):  
Catherine N. Mulligan ◽  
Bechara F. Safi ◽  
Jacques Meunier ◽  
Jean Chebib

Abstract The SNC multiplate reactor (1,200 L) has been developed and tested to determine chemical oxygen demand (COD) removal, nutrient requirement, and gas production from the anaerobic treatment of effluents generated at the Agropur (Notre Dame-du-Bon-Conseil, Quebec) and Nutrinor cheese dairies (Chambord, Quebec). At the Agropur plant, wastewater (3,000 mg/L COD) was treated the best at a retention time of 12 h. Using this retention time, effluents containing whey with organic loads of 10.2 to 41.6 kg COD/m3/day could be treated at a 84% COD removal rate. When the reactor was subjected to shock by increasing the organic load suddenly from 8.9 to 31 kg COD/m3/day, the total COD removal decreased to 72% and then returned to 86% after 7 days. Hydrology tests indicated that the reactor functions as a series of completely mixed stirred tanks. At Nutrinor, using a 12-h retention time and diluted whey permeate (20,000 mg/L COD), total COD removal was 86% and gas production was 12.0 m3/m3/day for a loading of 36.5 kg COD/m3/day. Nutrient supplementation was not required. For experiments performed with different proportions of wastewater (2,000 mg/L COD) to whey permeate (70,000 mg/L COD) results of 89% total and 93% soluble COD removal with a gas production of 11 m3/m3/day for a loading of 25 kg COD/m3/day were obtained. Retention times were varied from 18 to 60 h to correspond to initial CODs of 20,000 to 70,000 mg/L. In conclusion, this reactor functions in a superior manner to other published anaerobic treatment systems.


2011 ◽  
Vol 255-260 ◽  
pp. 2962-2966
Author(s):  
Rong Gui Fan ◽  
Chun E Li ◽  
Yong Xin Bai ◽  
Da Qing Huang ◽  
Liao Wei Fang ◽  
...  

The electrochemical oxidation of wastewater from DDNP production was investigated using a boron-doped diamond (BDD) thin film electrode. The effects of operating factors such as cell voltage, interelectrode distance and additive NaCl have been studied. This study showed that the chemical oxygen demand (COD) reduction is most influenced by the applied cell voltage. Higher current densities resulting from higher cell voltages increase the formation of oxidative reagents resulting in an increased COD removal rate. The maximum COD removal was 57% after 210 min, with an energy consumption of 14.90 KWh·kg-1 COD when cell voltage was 12V, interelectrode distance was 3cm and additive NaCl concentration was 1g·L-1. The use of BDD thin film electrode for the treatment of DDNP production wastewater appears commercially feasible.


2012 ◽  
Vol 550-553 ◽  
pp. 2232-2236 ◽  
Author(s):  
Pei Yao Xu ◽  
Xiu Jie Chu ◽  
Yan Qing Li ◽  
Fan Zhang

Abstract. With TiO2 as photocatalyst, hydrogen peroxide(H2O2) as oxidant, treated the coal chemical wastewater under the condition of 30W UV lamp irradiation. Discussed the effects of those factors—pH, dosage of TiO2 powder, dosage of FeCl3, dosage of H2O2 and illumination time etc. on Chemical Oxygen Demand(COD) removal rate of wastewater. The results have shown that: when taking the pH of raw water, TiO2 0.2g per 100ml wastewater, FeCl3 0.01g per 100ml wastewater, H2O2 1.2 ml per 100ml wastewater, 5h illumination time, quiet place 3h, acquired the best photocatalytic effect. After treated under the optimum technological conditions, the COD removal rate reached 70.09%; the removal rate of Biological Oxygen Demand(BOD5), ammonia nitrogen, cyanide and color reached respectively to 58.60%、39.99%, 72.41% and 90%. After repeated 10 times, all the active of TiO2 was almost lost. With the regeneration treatment by high-temperature cauterization, the regenerated catalyst was added into the raw wastewater. Then under the optimum technological conditions, after illuminated 7h, the COD removal rate of wastewater recovered to 49.47%.


Author(s):  
Tiancheng Hun ◽  
Binxia Zhao ◽  
Tingting Zhu ◽  
Linxue Liu ◽  
Zhiliang Li ◽  
...  

Abstract The iron oxychloride/pillared montmorillonite (FeOCl/MMT) catalyst was prepared by wet impregnation method and solid melting method. Various characterization techniques were used to analyze the microscopic morphology and structure of a series of catalysts. Moreover, the catalysts were used to treat magenta simulated dye wastewater through catalytic wet peroxide oxidation (CWPO) degradation. The magenta removal rate and chemical oxygen demand (COD) removal rate of the magenta simulated dye wastewater were used to evaluate the catalytic performance of the catalyst, and the optimal catalyst preparation conditions were selected. The results showed that the solid melting method was more favorable to the preparation of the catalyst, and the COD removal rate of wastewater can reach 70.8% when the FeOCl load was 3%. Moreover, 96.2% of the magenta in the solution has been removed. The COD removal rate of the magenta wastewater decreased by only 12.4% after the catalyst was repeatedly used six times, indicating that the catalyst has good activity and stability. The Fermi equation can simulate the reaction process of the catalyst treating magenta wastewater at high temperature.


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