High-rate stabilization of primary sludge in a single-chamber microbial hydrogen peroxide producing cell

2019 ◽  
Vol 5 (6) ◽  
pp. 1124-1131 ◽  
Author(s):  
Dongwon Ki ◽  
Rick Kupferer ◽  
César I. Torres
Keyword(s):  
Hydrogen Peroxide ◽  
High Rate ◽  
Primary Sludge ◽  
Single Chamber ◽  
Sludge Stabilization ◽  
Pathogen Indicators ◽  
Class B

High-rate sludge stabilization of wastewater primary sludge was achieved in single-chamber microbial peroxide producing cells meeting the requirements of pathogen indicators and vector attraction reductions for class B biosolids.

scholarly journals Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis

2021 ◽  
pp. 173-183
Author(s):  
Alexander I. Sizov ◽  
◽  
Sergey D. Pimenov ◽  
Anastasia D. Stroiteleva ◽  
Katherine D. Stroiteleva ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Pharmaceutical Industry ◽  
Gas Phase ◽  
Sodium Hypochlorite ◽  
Microcrystalline Cellulose ◽  
High Rate ◽  
Subsequent Formation ◽  
Hydrolysis Of Cellulose ◽  
Yellow Tint ◽  
Hydrolysis Of

One of the main consumers of microcrystalline cellulose (MCC) is the pharmaceutical industry, where MCC is used as a binder and filler in direct compression of tablets. MCC is produced by acidic hydrolysis of cellulose, which usually results in a decrease in whiteness. This is due to the destruction of sugars formed during hydrolysis and the subsequent formation of colored products. The composition and properties of these products depend on the method of hydrolysis, acid concentration, temperature, and process duration. One of the most promising methods for producing MCC is gas-phase hydrolysis of cellulose with hydrogen chloride gas-air mixtures. The method has a high rate of hydrolysis, low reagent and energy consumption. The requirements of the pharmaceutical industry determine the need to produce MCC with high whiteness. The research purpose is to select bleaching modes for MCC using sodium hypochlorite and hydrogen peroxide as bleaching agents. MCC produced by gas-phase hydrolysis of bleached wood pulp was used during the study. The whiteness and intensity of the yellow tint of MCC in the bleaching process were determined by digital colorimetry on a flatbed scanner. The paper shows that sodium hypochlorite and hydrogen peroxide allow achieving the whiteness not less than 90 % and the intensity of the yellow tint not more than 3 standard units. High-quality bleaching can be carried out even for MCC samples with an initial whiteness of about 40 %. The most effective bleaching agent is sodium hypochlorite when the pH of the bleaching solution is 2–3. Hydrogen peroxide also provides high whiteness of MCC at pH of 10–11. However, the consumption of active oxygen (AO) for bleaching is more than three times higher in comparison with the consumption of active chlorine (ACh). It was found that the dyes of MCC produced by gas-phase hydrolysis consist of two chromophore groups that decolorize at different rates. The easily oxidized group of components makes up about 90 % of the total amount of dyes, and the resistant to oxidation components make up about 10 % and determine the intensity of the yellow tint of MCC. The modes of bleaching MCC with sodium hypochlorite and hydrogen peroxide to product samples with whiteness comparable to that of imported samples were determined. For citation: Sizov A.I., Pimenov S.D., Stroiteleva A.D., Stroiteleva K.D. Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 173–183. DOI: 10.37482/0536-1036-2021-6-173-183

Impact of cold and dilute sewage on pre-fermentation - a case study

2001 ◽  
Vol 43 (11) ◽  
pp. 109-117 ◽  
Author(s):  
D. Bixio ◽  
P. van Hauwermeiren ◽  
C. Thoeye ◽  
P. Ockier
Keyword(s):  
Phosphorus Removal ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
High Rate ◽  
Cold Weather ◽  
Biological Nutrient Removal ◽  
Municipal Sewage ◽  
Biological Phosphorus Removal ◽  
Primary Sludge

The municipal sewage treatment plant (STP) of the city of Ghent (Belgium) has to be retrofitted to a 43%-increase in the nitrogen treatment capacity and to phosphorus removal. Cold weather, dilute sewage and a critical COD over N ratio make the retrofit a challenge for full biological nutrient removal. The potential for fermentation of primary sludge to alter those critical feed sewage characteristics was experimentally evaluated. The idea was that the pinpoint introduction of fermentate could optimise the available reactors by achieving high-rate denitrification and enhanced biological phosphorus removal. The fermentation process was evaluated with a bench scale apparatus. At 20°C (heated process), the hydrolysis yield - expressed in terms of soluble COD - varied from 11% to 24% of the total sludge COD. The fermentation yield expressed in VFA COD varied from 8% to 13% of the total sludge COD. The efficiency of heated fermentation of primary sludge was lower during cold and wet weather, due to the different sewage characteristics, as a result of extended dilution periods and low temperature. The raw sewage, the primary effluent and the fermentate were fractionated according to the requirements for the IAWQ Activated Sludge Model No. 2d. The results clearly show that fermentation in the sewer played an important role and temperature was the driving parameter for the characteristics of the dissolved COD. Instead, the weather flow conditions were the driving parameter for the characteristics of the suspended COD. The results of the detailed fractionation were used as background for process evaluation. The final scenario choice for the retrofit depends on a cost-efficiency calculation.

scholarly journals Koos Grade IV Vestibular Schwannomas: Considerations on a consecutive series of 60 cases. Searching for the Balance Between Preservation of Function and Maximal Tumor Removal

2021 ◽  
Author(s):  
Luciano Mastronardi ◽  
Alberto Campione ◽  
Fabio Boccacci ◽  
Carlo Giacobbo Scavo ◽  
Ettore Carpineta ◽  
...  
Keyword(s):  
Functional Results ◽  
Hearing Preservation ◽  
High Rate ◽  
Vestibular Schwannomas ◽  
Maximum Diameter ◽  
Consecutive Series ◽  
Tumor Diameter ◽  
Impaired Hearing ◽  
Class B ◽  
The Right

Abstract Purpose Koos Grade IV vestibular schwannomas (VS) (maximum diameter >3cm) compress the brainstem and displace the fourth ventricle. Microsurgical resection with attention to the right balance between preservation of function and maximal tumour removal is the treatment of choice.Methods Our series consists of 60 consecutive patients with unilateral VS, operated on from December 2010 to July 2019. All patients underwent microsurgical removal via the retrosigmoid approach. The adherence of VS’ capsule to surrounding nervous structures and the excessive tendency of tumor to bleed during debulking, because of a redundant vascular architecture, was evaluated by reviewing video records. Microsurgical removal of tumor was classified as total (T), near-total (NT: residue<5%), subtotal (ST: residue 5-10%) or partial (P: residue>10%).Results Maximal mean tumor diameter was 3,97cm (SD±1,13; range 3,1-5,8cm). Preoperative severely impaired hearing or deafness (AAO-HNS Classes C-D) was present in 52 cases (86,7%). Total or NT resection was accomplished in 46 cases (76,7%), 65,8% in cases with and 95,4% without tight adhesion of capsule to nervous structures (p<0,001). Endoscopic-assisted microsurgical removal of VS in the IAC was performed in 23 patients: in these cases a T resection was obtained in 78,3% versus 45,9% of microsurgery only (p<0,001).The capsule of VS was tightly adherent to nervous structures in 63,3% of patients, whereas hypervascular high-bleeding tumors represented 56,7%. Hearing preservation was possible in 2 out of 8 patients with preoperative class B hearing. At last follow-up, 34 patients (56,7%) had a normal postoperative FN outcome (HBI), 9 (15,0%) were HBII, 8 (13,3%) HBIII, and 9 (15,0%) HBIV. Total-NT resection of solid and low-bleeding VS, without tight capsule adhesion was associated with better FN outcome. Mortality was zero; permanent complications were observed in 2 cases (diplopia, hydrocephalus), transient in 9.Conclusions Microsurgery of Koos Grade IV VS seems to be associated with more than acceptable functional results, with high rate of T and NT removal of tumor. Long-term FN results seem to be worse in patients with cystic Koos Grade IV VS, in cases with tight capsule adherences to nervous structures and in high-bleeding tumors.

scholarly journals Alternativas en la estabilización de lodos provenientes de plantas de tratamiento de aguas residuales

2020 ◽  
Vol 5 (1) ◽  
pp. 23
Author(s):  
Jonathan Gustavo Castillo Sánchez ◽  
Luis David Balarezo Saltos ◽  
María Belén Vinces Obando ◽  
Héctor Andrés Zambrano Rizo
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Wastewater Treatment Plants ◽  
Organic Matter Content ◽  
Matter Content ◽  
Environment And Health ◽  
Sludge Stabilization ◽  
Sludge Characterization ◽  
Class B ◽  
Microbiological Parameters

La contaminación de los lodos que provienen de plantas de tratamiento de aguas residuales, afecta al medio ambiente y  a  la salud, por su contenido  de materia  orgánica, microorganismos y metales pesados. La presente investigación se realizó una caracterización físico-química y microbiológica en cuanto a humedad, proteínas, acidez, análisis del total de nitrógeno básico volátil (TVB-N), materia orgánica, metales pesados y parámetros microbiológicos con la finalidad de establecer la clase de lodo en base a las normativas ambientales internacionales, tales como USEPA, norma de la directiva europea y norma oficial mexicana, debido a la usencia de estas en el Ecuador. La concentración de metales se encuentra entre límite máximo de concentraciones estipulados por las tres normativas analizadas. En cuanto a los resultados de coliformes fecales se obtuvo 2,4x104 UFC/g, correspondiendo a un lodo de clase B según la USEPA; y a un lodo de clase C de acuerdo a la Norma Oficial Mexicana. En el presente se da un panorama general de los diferentes métodos de estabilización de lodos, en el cual se sugiere la utilización de cal debido a evidencias experimentales por diferentes investigaciones, siendo esta una de las más accesibles y eficientes.   Palabras claves— lodo residual, caracterización, estabilización, cal.   Abstract— Contamination of sludge from wastewater treatment plants affects the environment and health, because of their organic matter content, microorganisms and heavy metals. This research carried out a physical- chemical and microbiological characterization in terms of moisture, proteins, acidity, analysis of total volatile basic nitrogen (TVB-N), organic matter, heavy metals and microbiological parameters with the to establish the sludge class based on international environmental regulations, such as USEPA, the standard of the European directive and the official Mexican standard, due to the use of these in Ecuador. The concentration of metals is between the maximum limit of concentrations stipulated by the three regulations analyzed. As for the results of faecal coliforms, 2.4x104  CFUs/g was obtained, corresponding to a Class B sludge according to USEPA; and a Class C sludge according to the official Mexican standard. The present gives an overview of the different methods of sludge stabilization, in which  the use of lime is suggested  due to  experimental evidence by different research, this being one of the most accessible and efficient.   Index Terms— residual sludge, characterization, stabilization, lime.

Adapting UASB technology for sewage treatment in Palestine and Jordan

2008 ◽  
Vol 57 (3) ◽  
pp. 361-366 ◽  
Author(s):  
Nidal Mahmoud ◽  
Grietje Zeeman ◽  
JulesB. van Lier
Keyword(s):  
Sewage Treatment ◽  
Cost Effective ◽  
Pilot Scale ◽  
High Rate ◽  
Uasb Reactor ◽  
Temperate Climate ◽  
Model Calculations ◽  
Methanogenic Activity ◽  
Operational Conditions ◽  
Sludge Stabilization

High rate anaerobic technologies offer cost-effective solutions for “sewage” treatment in the temperate climate of Palestine and Jordan. However, local sewage characteristics demand amendments to the conventional UASB reactor design. A solution is found in a parallel operating digester unit that stabilises incoming solids and enriches the UASB sludge bed with methanogenic activity. The digester operational conditions were assessed by operating eight CSTRs fed with primary sludge. The results showed a high degree of sludge stabilization in the parallel digesters at SRTs≥10 and 15 days at process temperatures of 35 and 25°C, respectively. The technical feasibility of the UASB-digester combination was demonstrated by continuous flow pilot-scale experiments. A pilot UASB reactor was operated for 81 days at 6 hours HRT and 15°C and was fed with raw domestic sewage. This period was subsequently followed by an 83 day operation period incorporating a parallel digester unit, which was operated at 35°C. The UASB-digester combination achieved removal efficiencies of total, suspended, colloidal and dissolved CODs of respectively 66, 87, 44 and 30%. Preliminary model calculations indicated that a total reactor volume of the UASB-digester system corresponding to 8.6 hours HRT might suffice for sewage treatment in Palestine.

scholarly journals Destruction of the active substance of tetracycline under the action of UV irradiation

2021 ◽  
Vol 21 (3) ◽  
pp. 246-253
Author(s):  
Maria N. Ustinova ◽  
◽  
Nikita S. Zhunusov ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Uv Irradiation ◽  
Active Substance ◽  
Oxidative Degradation ◽  
High Rate ◽  
Universal Method ◽  
Iron Ions ◽  
Chemical Methods ◽  
Environmental Objects ◽  
Pharmaceutical Industries

The growth of the pharmaceutical industry inevitably leads to an increase in the concentration of organic pollutants in environmental objects. The problem of inactivation of such pollutants and water treatment is extremely urgent. The aim of this work was to use combined chemical methods of destruction of tetracycline, as one of the most commonly used antibiotics. The destruction of the active substance of tetracycline under UV irradiation, UV irradiation in the presence of hydrogen peroxide, and UV irradiation in the presence of hydrogen peroxide and ferrous iron ions was studied. It has been found that the active substance of tetracycline undergoes photodestruction at a fairly high rate, the degree of destruction reaches 75% within an hour. The kinetic characteristics of all three methods have been compared. It has been shown that the most intense oxidation of the active substance of tetracycline can be achieved by combined exposure to UV radiation and an oxidizer-hydrogen peroxide, after an hour the degree of destruction reaches 85.5%. However, the destruction of the active substance of the drug under UV irradiation in the presence of hydrogen peroxide and iron ions increases the initial speed of the process by 2–4 times, but reduces the efficiency to 66.7%. Photodestruction is quite effective, but not a universal method of inactivation of pollutants of pharmaceutical origin. In combination with oxidative degradation, it can be considered as a promising method for inactivating unusable drugs, as well as a method for local wastewater treatment in clinics and pharmaceutical industries.

Approaching a High-Rate and Sustainable Production of Hydrogen Peroxide: Oxygen Reduction on Co-N-C Single-Atom Electrocatalysts in Simulated Seawater

2021 ◽  
Author(s):  
Qinglan Zhao ◽  
Yian Wang ◽  
Wei-Hong Lai ◽  
Fei Xiao ◽  
Yuxiang Lyu ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Oxygen Reduction ◽  
Flow Cell ◽  
Cell System ◽  
High Rate ◽  
Single Atom ◽  
Promising Alternative ◽  
Production Of Hydrogen ◽  
Electrochemical Production ◽  
Simulated Seawater

Electrochemical production of H2O2 from O2 using simulated seawater provides a promising alternative to the energy-intensive industrial anthraquinone process. In this study, a flow cell system is built for electrocatalytic...

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