scholarly journals Bioaugmentation with Mixed Hydrogen-Producing Acetogen Cultures Enhances Methane Production in Molasses Wastewater Treatment

Archaea ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Shuo Wang ◽  
Jianzheng Li ◽  
Guochen Zheng ◽  
Guocheng Du ◽  
Ji Li
Keyword(s):  
Wastewater Treatment ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Anaerobic Wastewater Treatment ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Molasses Wastewater ◽  
Cod Removal Rate ◽  
Rate Limiting

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.

Elevated Nitrite Occurrence in Biological Wastewater Treatment Systems

1985 ◽  
Vol 17 (2-3) ◽  
pp. 409-419 ◽  
Author(s):  
J. E. Alleman
Keyword(s):  
Wastewater Treatment ◽  
Oxygen Demand ◽  
Biological Wastewater Treatment ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Nitrite Toxicity ◽  
Chlorine Demand ◽  
Rate Limiting ◽  
Wastewater Treatment Systems ◽  
Initial Conversion

The initial conversion of ammonium to nitrite by Nitrosomonas has traditionally been regarded as the rate-limiting step for nitrification metabolism. This perspective implicitly assumes that subsequent oxidation of nitrite by Nitrobacter occurs more rapidly, and that NO2 concentrations are consequently maintained at low, sub-mg/L values. However, numerous bench- and full-scale nitrification systems have reportedly encountered elevated nitrite concentrations. Several concerns are generated by this circumstance, including: a) an increased chlorine demand, b) an increased effluent nitrogenous oxygen demand, c) potential nitrite toxicity, and d) possible nitrosamine formation. This paper consequently provides an overview of seven conditions which could lead to elevated nitrite occurrence in biological nitrification systems.

scholarly journals Study of COD Removal Rate on a Sequencing Batch Reactor (SBR) Treating Tapioca Wastewater

2019 ◽  
Vol 38 (3) ◽  
pp. 243
Author(s):  
Happy Mulyani ◽  
Gregorius Prima Indra Budianto ◽  
Margono Margono ◽  
Mujtahid Kaavessina
Keyword(s):  
Wastewater Treatment ◽  
Sequencing Batch Reactor ◽  
Removal Rate ◽  
Batch Reactor ◽  
Cod Removal ◽  
Operation Condition ◽  
Effluent Quality ◽  
Aeration Time ◽  
Standard Quality ◽  
Cod Removal Rate

Industrial wastewater treatment using Sequencing Batch Reactor (SBR) can improve effluent quality at lower cost than that obtained by other biological treatment methods. Further optimization is still required to enhance effluent quality until it meets standard quality and to reduce the operating cost of treatment of high strength organic wastewater. The purpose of this research was to determine the effect of pretreatment (pH adjustment and prechlorination) and aeration time on effluent quality and COD removal rate in tapioca wastewater treatment using SBR. Pretreatment was done by (1) adjustment of tapioca wastewater pH to control (4.92), 7, and 8, and (2) tapioca wastewater prechlorination at pH 8 during hour using calcium hypochlorite in variation dosages 0, 2, 4, 6 mg/L Cl2, SBR operation was conducted according to following steps: (1) Filling of pre-treated wastewater into a bioreactor during 1 hour, and (2) aeration of the mixture of tapioca wastewater and activated sludge during 8 hours. Effluent sample was collected at every 2-hours aeration for COD analysis. COD removal rate mathematical formula was got by first deriving the best fit function between aeration time and COD. Optimum aeration time resulting in no COD removal rate. The value of COD effluent and its removal rate in optimum aeration time was used to determine the recommended of operation condition of pretreatment. Research result shows that chosen pH operation condition is pH 8. Prechorination can make effluent quality which meets standard quality and highest COD removal rate. The chosen Cl2 dosage is 6 mg/L.

scholarly journals Combined Application of UV Photolysis and Ozonation with Biological Aerating Filter in Tertiary Wastewater Treatment

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Zhaoqian Jing ◽  
Shiwei Cao
Keyword(s):  
Molecular Weight ◽  
Wastewater Treatment ◽  
Organic Pollutants ◽  
Wastewater Treatment Plants ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Secondary Effluent ◽  
Uv Photolysis ◽  
Combined Application

To enhance the biodegradability of residual organic pollutants in secondary effluent of wastewater treatment plants, UV photolysis and ozonation were used in combination as pretreatment before a biological aerating filter (BAF). The results indicated that UV photolysis could not remove much COD (chemical oxygen demand), and the performance of ozonation was better than the former. With UV photolysis combined with ozonation (UV/O3), COD removal was much higher than the sum of that with UV photolysis and ozonation alone, which indicated that UV photolysis could efficiently promote COD removal during ozonation. This pretreatment also improved molecular weight distribution (MWD) and biodegradability greatly. Proportion of organic compounds with molecular weight (MW) <3 kDalton was increased from 51.9% to 85.9%. COD removal rates with BAF and O3/BAF were only about 25% and 38%, respectively. When UV/O3oxidation was combined with BAF, the average COD removal rate reached above 61%, which was about 2.5 times of that with BAF alone. With influent COD ranging from 65 to 84 mg/L, the effluent COD was stably in the scope of 23–31 mg/L. The combination of UV/O3oxidation with BAF was quite efficient in organic pollutants removal for tertiary wastewater treatment.

Combined technology for clomazone herbicide wastewater treatment: three-dimensional packed-bed electrochemical oxidation and biological contact degradation

2013 ◽  
Vol 68 (1) ◽  
pp. 257-260 ◽  
Author(s):  
Yujie Feng ◽  
Junfeng Liu ◽  
Limin Zhu ◽  
Jinzhi Wei
Keyword(s):  
Electrochemical Oxidation ◽  
Organic Contaminants ◽  
Removal Rate ◽  
Three Dimensional ◽  
Oxygen Demand ◽  
Cell Voltage ◽  
Packed Bed ◽  
Cod Removal ◽  
Cod Removal Rate ◽  
Oxidation Reactor

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.

Aerobic treatment of inhibitory wastewater using a high-pressure bioreactor with membrane separation

2001 ◽  
Vol 43 (11) ◽  
pp. 51-58 ◽  
Author(s):  
P. C. Male ◽  
W. A. Pretoruis
Keyword(s):  
High Pressure ◽  
Membrane Separation ◽  
Removal Rate ◽  
Oxygen Demand ◽  
High Strength ◽  
Cod Removal ◽  
Stable Operating ◽  
Ultra Filtration ◽  
Biomass Loss ◽  
Cod Removal Rate

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.

Anaerobic Treatment of Cheese Dairy Wastewater Using the SNC Bioreactor

1993 ◽  
Vol 28 (3) ◽  
pp. 597-620 ◽  
Author(s):  
Catherine N. Mulligan ◽  
Bechara F. Safi ◽  
Jacques Meunier ◽  
Jean Chebib
Keyword(s):  
Retention Time ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Gas Production ◽  
Cod Removal ◽  
Dairy Wastewater ◽  
Organic Load ◽  
Whey Permeate ◽  
Cod Removal Rate

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.

Electrochemical Pretreatment of Wastewater from DDNP Production Using BDD Thin Film Electrode

2011 ◽  
Vol 255-260 ◽  
pp. 2962-2966
Author(s):  
Rong Gui Fan ◽  
Chun E Li ◽  
Yong Xin Bai ◽  
Da Qing Huang ◽  
Liao Wei Fang ◽  
...  
Keyword(s):  
Thin Film ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Cell Voltage ◽  
Cod Removal ◽  
Interelectrode Distance ◽  
Film Electrode ◽  
Boron Doped Diamond ◽  
Thin Film Electrode ◽  
Cod Removal Rate

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.

Research on Coal Chemical Wastewater Treatment by Nano-TiO2 Powder Photocatalytic Oxidation Process

2012 ◽  
Vol 550-553 ◽  
pp. 2232-2236 ◽  
Author(s):  
Pei Yao Xu ◽  
Xiu Jie Chu ◽  
Yan Qing Li ◽  
Fan Zhang
Keyword(s):  
Photocatalytic Oxidation ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Cod Removal ◽  
Illumination Time ◽  
Photocatalytic Effect ◽  
Uv Lamp ◽  
Cod Removal Rate ◽  
Raw Wastewater

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%.

scholarly journals Catalytic wet peroxide oxidation degradation of magenta wastewater and preparation of FeOCl/montmorillonite

2021 ◽  
Author(s):  
Tiancheng Hun ◽  
Binxia Zhao ◽  
Tingting Zhu ◽  
Linxue Liu ◽  
Zhiliang Li ◽  
...  
Keyword(s):  
Removal Rate ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Impregnation Method ◽  
Dye Wastewater ◽  
Peroxide Oxidation ◽  
Melting Method ◽  
Wet Peroxide Oxidation ◽  
Catalytic Wet Peroxide Oxidation ◽  
Cod Removal Rate

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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