Hydrogen sulphide removal by activated sludge diffusion

2004 ◽  
Vol 50 (4) ◽  
pp. 199-205 ◽  
Author(s):  
V.L. Barbosa ◽  
D. Dufol ◽  
J.L. Callan ◽  
R. Sneath ◽  
R.M. Stuetz
Keyword(s):  
Activated Sludge ◽  
Hydrogen Sulphide ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Pilot Scale ◽  
Gas Treatment ◽  
Noticeable Increase ◽  
Waste Gas Treatment ◽  
Odour Concentration ◽  
And Control

Odours from wastewater treatment plants comprise a mixture of various gases, of which hydrogen sulphide (H2S) is the main constituent. Microorganisms commonly found in wastewater can degrade sulphurous compounds. Therefore, the use of activated sludge (AS) for odour control offers an alternative to traditional waste gas treatment processes, such as biofilters, bioscrubbers and biotrickling filters, both in practical terms (use of existing facilities) and economically (minimal capital cost). The performance of AS diffusion as a bioscrubber for removing H2S at concentrations at 25, 75 and 150 ppmv was evaluated. Pilot-scale trials were undertaken using parallel 60-L aeration tanks and 20-L clarifier reactors at the Bedford Sewage Treatment Works, Carington, UK. Olfactometry measurements were also carried out to determine whether there was any increase in odour concentration owing to H2S diffusion. Hydrogen sulphide removal rates of 100% were obtained, with no noticeable increase in odour concentration throughout the trials as measured by olfactometry. Odour concentration was highest at the beginning of the trials and lowest during the high H2S dosing period, with similar values being obtained for test and control. It was concluded that AS diffusion is an effective bioscrubber for the removal of H2S odour.

Sewage treatment works odour measurement

2000 ◽  
Vol 41 (6) ◽  
pp. 33-40 ◽  
Author(s):  
P. Gostelow ◽  
S. A. Parsons
Keyword(s):  
Hydrogen Sulphide ◽  
Sewage Treatment ◽  
Dispersion Models ◽  
Single Measure ◽  
Unit Operations ◽  
Sulphide Concentration ◽  
Odour Concentration ◽  
And Control ◽  
The Relationship ◽  
Human Nose

Public concern over odours from sewage treatment works is increasing. More people are being exposed to odours, due to development around existing works or the construction of new works. Raised awareness of both the environment and individual rights has meant people are now more likely to complain. Odourabatement and control is a major issue for sewage works operators. To control odours, they must first be measured. This is no easy task as response to odours is subjective and our understanding of the sense of smell is incomplete. In assessing an odour nuisance, odour formation, emission, dispersion and perception must be considered. There is no single measure that is suitable for this purpose. Odour measurements fall into two classes. Analytical measurements characterise odours in terms of their chemical composition and are more suited to formation, emission and dispersion models. Unfortunately, they tell us little about the perceived effect of the odour. Sensory measurements employ the human nose and characterise odours in terms of their perceived effect. A link between analytical and sensory measurements is clearly needed. In this paper data collected from odour surveys at 17 different wastewater treatment sites are evaluated to explore possibilities for linking analytical and sensory measures. The relationship between hydrogen sulphide concentration and odour concentration as measured by threshold olfactometry is explored. Correlations suggest power-law relationships between hydrogen sulphide and odour concentration, with r2 values as high as 0.69. This paper will assess the use of hydrogen sulphide (H2S) and olfactometry measurements for a range of unit operations and abatement technologies.

Performance of activated sludge diffusion for biological treatment of hydrogen sulphide gas emissions

2013 ◽  
Vol 68 (9) ◽  
pp. 1932-1939 ◽  
Author(s):  
Vera L. Barbosa ◽  
Richard M. Stuetz
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Hydrogen Sulphide ◽  
Biological Treatment ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Broad Application ◽  
H2s Removal ◽  
Treatment Performance ◽  
Solids Concentration

Odours from wastewater treatment plants are comprised of a mixture of various gases with hydrogen sulphide (H2S) often being the dominant constituent. Activated sludge diffusion (ASD) as a biotreatment system for odour abatement has been conducted for over 30 years but has limited broad application due to disagreement in the literature regarding the effect that ASD may have on wastewater treatment performance. The effects of continuous H2S diffusion at 25 ppmv, with weekly peaks of approximately 100 ppmv, on H2S removal efficiency and wastewater treatment performance was evaluated over a 2-month period using an activated sludge pilot plant. H2S removal averaged 100% during diffusion at 25 ppmv, and 98.9% during the 100 ppmv peak periods. A significant increase in mixed liquor volatile suspended solids concentration (P < 0.01) was observed during H2S diffusion, which may be due to an increase in H2S-degrading microorganisms. There was no adverse effect of H2S on nitrification throughout the ASD trials. Ammonia (NH3) removal was slightly better in the test receiving H2S diffusion (87.6%) than in the control (85.4%). H2S diffusion appeared to improve robustness of the AS biomass to operational upsets.

scholarly journals Aeration control – a review

2013 ◽  
Vol 67 (11) ◽  
pp. 2374-2398 ◽  
Author(s):  
L. Åmand ◽  
G. Olsson ◽  
B. Carlsson
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Control Strategies ◽  
Pilot Scale ◽  
Special Focus ◽  
Municipal Wastewater Treatment ◽  
Optimal Controllers ◽  
Municipal Wastewater Treatment Plants ◽  
And Control ◽  
Published Research

This review covers automatic control of continuous aeration systems in municipal wastewater treatment plants. The review focuses on published research in the 21st century and describes research into various methods to decide and control the dissolved oxygen (DO) concentration and to control the aerobic volume with special focus on plants with nitrogen removal. Important aspects of control system implementation and success are discussed, together with a critical review of published research on the topic. With respect to DO control and determination, the strategies used for control span from modifications and developments of conventional control methods which have been explored since the 1970s, to advanced control such as model-based predictive and optimal controllers. The review is supplemented with a summary of comparisons between control strategies evaluated in full-scale, pilot-scale and in simulations.

scholarly journals Reliability of removal of selected pollutants in different technological solutions of household wastewater treatment plants

2017 ◽  
Vol 35 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Michał Marzec
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Total Suspended Solids ◽  
Hybrid Reactor ◽  
Limit Values

AbstractThe reliability of removal of selected contaminants in three technological solutions of the household sewage treatment plants was analysed in this paper. The reliability of the sewage treatment plant with activated sludge, sprinkled biological deposit and hybrid reactor (activated sludge and immersed trickling filter) was analyzed. The analysis was performed using the Weibull method for basic indicators of impurities, BOD5, COD and total suspended solids. The technological reliability of the active sludge treatment plant was 70% for BOD5, 87% for COD and 66% for total suspended solids. In the sewage treatment plant with a biological deposit, the reliability values determined were: 30% (BOD5), 60% (COD) and 67% (total suspended solids). In a treatment plant with a hybrid reactor, 30% of the BOD5and COD limit values were exceeded, while 30% of the total suspended solids were exceeded. The reliability levels are significantly lower than the acceptable levels proposed in the literature, which means that the wastewater discharged from the analysed wastewater treatment plants often exceeds the limit values of indicators specified in currently valid in Poland Regulation of the Minister of Environment for object to 2000 population equivalent.

The ability of selected chemicals for suppressing odour development in rising mains

2000 ◽  
Vol 41 (6) ◽  
pp. 165-173 ◽  
Author(s):  
J. Hobson ◽  
G. Yang
Keyword(s):  
Ferric Chloride ◽  
Hydrogen Sulphide ◽  
Pilot Scale ◽  
Ferric Ions ◽  
Ferric Salt ◽  
Odour Concentration ◽  
Odour Removal

The use of Nutriox® and ferric chloride to suppress hydrogen sulphide and odour generation in rising mains is evaluatd in a pilot scale study. Without chemical dosing the hydrogen sulphide built up to the commonly predicted levels after six months. Thereafter, addition of both Nutriox® and ferric chloride to sewage entering the rising main totally suppressed the formation of H2S. Nutriox also nearly totally suppressed the odour measured olfactometrically. The use of ferric salt at near stoichiometric levels effectively removed dissolved sulphide. Odour removal was generally good though on occasions reduction of dissolved sulphide levels to below 0.1 mg/l was not guaranteed to be accompanied by near total suppression of odour generation. The use of ferric ions at stoichiometric levels, after H2S and odours have formed in the rising main, also eliminated the dissolved sulphide. When used in this way, a significant residual odour potential, 110,000 ou/m3 remained in the sewage. The simultaneous reductions of odour and hydrogen sulphide observed in this study implied an apparent threshold odour concentration of 0.1 ppb for H2S, significantly lowr than most values quoted in the literature.

FOAMING CAUSES AND CONTROL IN ACTIVATED SLUDGE WASTEWATER TREATMENT PLANTS

2006 ◽  
Vol 5 (6) ◽  
pp. 1407-1413
Author(s):  
Ileana Ghita ◽  
Elisabeta Pena-Leonte ◽  
Aurelia Ballo ◽  
Cristiana Cosma ◽  
Ciprian Dumitrescu ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
And Control

Causes and control practices of filamentous foaming in wastewater treatment plants

2012 ◽  
Vol 7 (3) ◽  
Author(s):  
D. Mamais ◽  
M. Marneri ◽  
C. Noutsopoulos
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Economic Feasibility ◽  
Control Methods ◽  
Filamentous Bacteria ◽  
Foam Control ◽  
Filamentous Foaming ◽  
And Control ◽  
Athens Area

Three large Wastewater Treatment Plants (WWTP) in Greece with occasional severe foaming were selected in order to evaluate the influence of the recycle of foaming filamentous bacteria from the solids handling processes to their foaming problems. According to the results, a range of 3–39% of the total quantity of viable foaming filamentous bacteria present in biological wastewater treatment stage of the WWTPs was found to be recycled through the underflows of thickening and dewatering processes. In parallel, the feasibility of alternative nonspecific foam control methods was assessed. Within the context of this study two foam control practices were evaluated: (a) the addition of polyaluminium chloride (PAX) to the mixed liquor and (b) the selective wasting of foam from the activated sludge system followed by dewatering. The economic feasibility of each method was assessed by evaluating and comparing the total cost (capital cost and operation and maintenance costs) of each alternative for Psyttalia Sewage Treatment Works, which is the largest WWTP in Greece serving the Greater Athens Area with a treatment capacity of approximately 3.5 million people. The estimated total costs of the two foam control methods were 0.009 and 0.002 €/m3 of wastewater for PAX addition and selective wasting of foam, respectively.

Oxidation-reduction potential (ORP) regulation of nutrient removal in activated sludge wastewater treatment plants

2002 ◽  
Vol 46 (1-2) ◽  
pp. 35-39 ◽  
Author(s):  
B. Li ◽  
P. Bishop
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Redox Status ◽  
Organic Substrate ◽  
Microbial Biodegradation ◽  
Scale Experiment ◽  
One Year

Redox potential (ORP) regulation of nutrient removal in aeration tanks was tested for one year in three activated sludge wastewater treatment plants in Cincinnati, OH. The experiment results show a good relationship between ORP values and nutrient removal. Macro-biodegradation and sorption of substrate by activated sludge can significantly increase wastewater ORP, indicating the improvement of redox status of the bulk liquor. DO higher than 1.0 mg/L is necessary for good biodegradation and the improvement of liquid redox status. ORP values at higher temperatures (Twater=20–26°C) were lower than ORP values at lower temperatures (Twater=14–19°C), caused by the lower oxygen saturation capacity in wastewater and the more rapid oxygen consumption by microorganism under warmer conditions. Nitrification occurred at higher ORP values (380 mV) than did organic substrate oxidation (250mV). This verifies that different metabolic processes dominate in different ORP ranges. The pilot-scale experiment results demonstrate that the wastewater ORP values continued to increase throughout the whole 6-hour cycle when the influent COD was higher than 1,000 mg/L. For influent with low COD (40–120 mg/L), the wastewater ORP values did not increase in the second 3 hours of the cycle, during which time the microbial-biodegradation within the activated sludge floc dominated. High DO concentrations (6–8 mg/L) did not help improve the redox status. In fully-aerated wastewater, oxygen deeply penetrated into the activated sludge flocs, and microorganisms biodegraded the substrates within the flocs. Endogenous metabolism predominated.

Treatment of waste activated sludge together with agro-waste by anaerobic digestion: focus on effluent quality

2013 ◽  
Vol 69 (3) ◽  
pp. 525-531 ◽  
Author(s):  
C. Cavinato ◽  
C. Da Ros ◽  
P. Pavan ◽  
F. Cecchi ◽  
D. Bolzonella
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Point Of View ◽  
Waste Activated Sludge ◽  
Organic Substrates ◽  
Economic Point ◽  
Energetic Balance

Waste activated sludge production and management plays an important role in wastewater treatment plants (WWTPs), especially from an economic point of view. One possible approach is the anaerobic co-digestion of waste activated sludge with others organic substrates in mesophilic and thermophilic conditions in order to exploit the spare volume of existing reactors, recover energy from biogas production, and obtain a fertilizer as final product. The anaerobic trials were carried out at pilot scale, applying two organic loading rates (2.8 and 4.5 kg chemical oxygen demand (COD)/(m3·d)) with a hydraulic retention time of 16 and 21 days. Among agro-wastes, wine lees were chosen because of their continuous availability throughout the year, and their high COD content (up to 200–300 g/l, 70% soluble, on average). The addition of wine lees to activated sludge determined a higher biogas production (best yield was 0.40 Nm3/kgCODfed) improving the energetic balance of the sludge line of the WWTP. The characterization of both substrates fed and digester effluents was carried out in terms of heavy metals; comparison with EC proposed limits showed that, due to high content of Cu in wine lees, the loading rate of this agro-waste should be limited to maintain good characteristics of final biosolids.

Modelling of wastewater treatment plants – how far shall we go with sophisticated modelling tools?

2006 ◽  
Vol 53 (3) ◽  
pp. 79-89 ◽  
Author(s):  
G.C. Glover ◽  
C. Printemps ◽  
K. Essemiani ◽  
J. Meinhold
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Full Scale ◽  
Structure Identification ◽  
Oxidation Ditch ◽  
Computational Fluid Dynamics Analysis

Several levels of complexity are available for modelling of wastewater treatment plants. Modelling local effects rely on computational fluid dynamics (CFD) approaches whereas activated sludge models (ASM) represent the global methodology. By applying both modelling approaches to pilot plant and full scale systems, this paper evaluates the value of each method and especially their potential combination. Model structure identification for ASM is discussed based on a full-scale closed loop oxidation ditch modelling. It is illustrated how and for what circumstances information obtained via CFD (computational fluid dynamics) analysis, residence time distribution (RTD) and other experimental means can be used. Furthermore, CFD analysis of the multiphase flow mechanisms is employed to obtain a correct description of the oxygenation capacity of the system studied, including an easy implementation of this information in the classical ASM modelling (e.g. oxygen transfer). The combination of CFD and activated sludge modelling of wastewater treatment processes is applied to three reactor configurations, a perfectly mixed reactor, a pilot scale activated sludge basin (ASB) and a real scale ASB. The application of the biological models to the CFD model is validated against experimentation for the pilot scale ASB and against a classical global ASM model response. A first step in the evaluation of the potential of the combined CFD-ASM model is performed using a full scale oxidation ditch system as testing scenario.

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