Improving the hydrobiological analysis of activated sludge at the Minsk wastewater treatment facilities

2021 ◽  
pp. 26-36
Author(s):  
О.С. Дубовик ◽  
Р.М. Маркевич ◽  
Е.В. Гаврилович ◽  
И.А. Гребенчикова ◽  
В.В. Иванович
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Point System ◽  
Treatment Conditions ◽  
Filamentous Microorganisms ◽  
Different Seasons ◽  
Treatment Facilities ◽  
Favorable Conditions ◽  
Quantitative Account ◽  
Different Levels

На основании накопленного опыта эксплуатации сооружений Минской очистной станции и обзора источников информации определена схема гидробиологического анализа активного ила, приведена форма регистрации результатов проведенного анализа. Для количественного учета нитчатых микроорганизмов разработана собственная пятибалльная система. Для нитчатых микроорганизмов, выявленных в активном иле, на основании анализа литературных данных определены условия, благоприятствующие их массовому развитию. В течение длительного периода времени, включающего разные сезоны года, проведена апробация усовершенствованной методики для мониторинга состояния иловой суспензии очистных сооружений двух площадок станции: классических четырехкоридорных аэротенков-вытеснителей первой площадки и биореакторов с каскадной денитрификацией второй площадки. Определены представители нитчатых микроорганизмов, постоянно обитающие в очистных сооружениях, выявлены доминирующие виды. Проведено сопоставление результатов анализа нитчатых форм и седиментационных характеристик активного ила. Сделаны заключения об особенностях биоценоза аэротенков первой площадки и биореакторов второй площадки, идентичности по видовому составу сообществ нитчатых бактерий, влиянии состава сточных вод и условий их очистки (нагрузка на ил, наличие зон с разным уровнем аэрации) на свойства иловой суспензии. Based on the accumulated experience in operating the Minsk Wastewater Treatment Facilities and a review of information sources, a scheme for the hydrobiological analysis of activated sludge was determined, and a form for recording the results of the analysis was provided. For the quantitative account of filamentous microorganisms, an original five-point system was developed. Based on the literature data analysis, favorable conditions for the mass growth of filamentous microorganisms found in activated sludge were determined. Over a long period of time, including different seasons of the year, the improved methodology was tested for monitoring the state of the sludge suspension at two sites of the treatment facilities: traditional four-line continuous-flow aeration tanks at the first site and bioreactors with cascade denitrification at the second site. The species of filamentous microorganisms, permanently living in wastewater treatment structures, have been identified, and the dominant species have been determined. The results of the analysis of filamentous forms and sedimentation characteristics of activated sludge are compared. Conclusions were made about the features of the biocenosis in the aeration tanks at the first site and in the bioreactors at the second site; about the identity of the species composition of the filamentous bacteria communities, the effect of the wastewater composition and treatment conditions (sludge load, occurrence of zones with different levels of aeration) on the properties of the sludge suspension.

Biological odour control by diffusion into activated sludge basins

2000 ◽  
Vol 41 (6) ◽  
pp. 127-132 ◽  
Author(s):  
R. P. Bowker
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
High Strength ◽  
Air Stream ◽  
Fine Bubble ◽  
Treatment Facilities ◽  
Odour Control ◽  
Odour Emissions ◽  
Air Streams

Diffusion of odourous air into activated sludge basins is an effective and economical approach for odour control at wastewater treatment plants. Over 30 facilities in North America practice this technique. Most of these applications are for dilute or moderate strength air streams with relatively low hydrogen sulfide (H2S) levels. Unfortunately, the lack of data documenting the effectiveness of the process and concerns for blower corrosion have limited its acceptance as a method for controlling odour emissions. This paper presents a compilation and review of wastewater treatment facilities that are currently using activated sludge diffusion. Performance data are tabulated, and information on operation and maintenance of the blower/diffuser systems are summarized. New data are presented that compare the effectiveness of coarse vs. fine bubble diffusers for treatment of a high strength, high-H2S air stream from sludge holding tanks at Concord, NH. Designand performance information is presented on a dedicated odour control system installed at Phoenixville, Pennsylvania in 1996 that collects high-H2S air streams from an influent chamber and primary clarifiers and diffuses it into a mechanically-aerated activated sludge basin. A cost-effectiveness analysis is presented for a blower/diffuser system installed exclusively for odour control. Methods used to overcome initial operational problems are discussed.

Non-filamentous sludge bulking caused by a deficiency of nitrogen in industrial wastewater treatment

2003 ◽  
Vol 47 (11) ◽  
pp. 289-295 ◽  
Author(s):  
Y. Peng ◽  
C. Gao ◽  
S. Wang ◽  
M. Ozaki ◽  
A. Takigawa
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Industrial Wastewater ◽  
Removal Rate ◽  
Nitrogen Deficiency ◽  
Utilization Rate ◽  
Industrial Wastewater Treatment ◽  
N Value ◽  
Sludge Bulking ◽  
Filamentous Microorganisms

Deficiency in the nutrient supply such as nitrogen usually results in activated sludge bulking and this phenomenon often takes place in the industrial wastewater treatment plants with activated sludge process. The effects of nitrogen deficiency on activated sludge bulking were studied specially in some experiments carried out in a sequencing batch reactor fed with brewing process wastewater in this paper. The experimental results showed that the sludge settled properly at an influent BOD/N value of 100/4. When the value of BOD/N was 100/3, filaments had an excessive growth at one time during the reaction process. Afterwards, the number of filamentous bacteria began to reduce and simultaneously an excessive growth of viscous Zoogloea with high percentage of moisture was observed and non-filamentous activated sludge bulking occurred. When the influent BOD/N value was 100/2, the excessive growth of filamentous microorganisms could not be observed at all times and the sludge characterization was similar to the case in which BOD/N value was 100/3. When the value of influent BOD/N was 100/0.94, more serious non-filamentous bulking occurred. Furthermore, the effects of nitrogen deficiency on the nitrogen sources and phosphorus sources utilization rate and the COD removal rate were investigated in the experiments.

scholarly journals The present situation and trends of wastewater treatment in small settlements and rural areas of Lithuania

2019 ◽  
pp. 243-250
Author(s):  
Regimantas Dauknys
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Surface Waters ◽  
Rural Areas ◽  
Biological Treatment ◽  
Wastewater Treatment Plants ◽  
Present Situation ◽  
Treatment Facilities ◽  
Biological Filters ◽  
Activated Sludge Systems

This article presents the wastewater treatment in small settlements and rural areas ofLithuania, including descriptions of capacity and loading of wastewater treatment plants(WWTPs), types of treatment facilities, and development trends of biological treatmentfacilities. In 2000 Lithuania had 597 WWTPs with capacity up to 1000 m3/d, 95% of them arethe biological treatment plants. Today the most of these WWTPs are unloaded due to thetendency to centralise wastewater treatment in rural areas of Lithuania that were in the eightand ninth decades.In small settlements and rural areas of Lithuania the aeration facilities are predominant. In theeight and ninth decades practically only the activated sludge systems were built. The situationbegan to change in the last decade of the last century: the biological filters and soil filtrationfacilities with discharge into surface waters were applied more frequently, so the building ofaeration facilities started to decrease.

scholarly journals Different engineering designs have profoundly different impacts on the microbiome and nitrifying bacterial populations in municipal wastewater treatment bioreactors

2021 ◽  
Author(s):  
Taegyu Kim ◽  
Sebastian Behrens ◽  
Timothy LaPara
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Community Composition ◽  
Municipal Wastewater ◽  
Specific Treatment ◽  
Treatment Goals ◽  
Municipal Wastewater Treatment ◽  
Α Diversity ◽  
Treatment Facilities ◽  
System Designs

Numerous wastewater treatment processes are designed by engineers to achieve specific treatment goals. However, the impact of these different process designs on bacterial community composition is poorly understood. In this study, 24 different municipal wastewater treatment facilities (37 bioreactors) with various system designs were analyzed by sequencing of PCR-amplified 16S rRNA gene fragments. Although a core microbiome was observed in all of the bioreactors, the overall microbial community composition (analysis of molecular variance; P = 0.001) as well as a specific population of Nitrosomonas spp. ( P = 0.04) were significantly different between A/O (anaerobic/aerobic) systems and conventional activated sludge (CAS) systems. Community α-diversity (number of observed operational taxonomic units [OTUs] and Shannon diversity index) was also significantly higher in A/O systems compared to CAS systems (Wilcoxon; P < 2 × 10 −16 ). In addition, wastewater bioreactors with short mean cell residence time (< 2 days) had very low community α-diversity and fewer nitrifying bacteria compared to other system designs. Nitrospira spp. (0.71%) and Nitrotoga spp. (0.41%) were the most prominent nitrite oxidizing bacteria (NOB); because these two genera were rarely prominent community members at the same time, these populations appeared to be functionally redundant. Weak evidence (AOB:NOB ≪ 2; substantial quantities of Nitrospira spp. sublineage II) was also obtained suggesting that complete ammonia oxidation by a single organism was occurring in system designs known to impose stringent nutrient limitation. This research demonstrates that design decisions made by wastewater treatment engineers significantly impact the microbiome of wastewater treatment bioreactors. IMPORTANCE Municipal wastewater treatment facilities rely on the application of numerous “activated sludge” process designs to achieve site-specific treatment goals. A plethora of microbiome studies on municipal wastewater treatment bioreactors have been previously performed; however, the role of process design on the municipal wastewater treatment microbiome is poorly understood. In fact, wastewater treatment engineers have attempted to control the microbiome of wastewater bioreactors for decades without sufficient empirical evidence to support their design paradigms. Our research demonstrates that engineering decisions with respect to system design have a significant impact on the microbiome of wastewater treatment bioreactors.

Biological Foams: The Cause-Effect Relationship, Test Results and Combat Strategy

1994 ◽  
Vol 29 (7) ◽  
pp. 239-247 ◽  
Author(s):  
Ph. Duchene
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Test Results ◽  
Private Companies ◽  
Effect Relationship ◽  
Filamentous Microorganisms

This paper presents the results obtained by “G.I.S. MOUSSES”, which comprises the CEMAGREF and the six main private companies operating wastewater treatment plants (WWTP) throughout FRANCE. Over 75% of French activated sludge (AS) WWTP, 20% are reported to be affected by foaming. 60% of theseare linked with Microthrix and only 14 % with Nocardioforms. Few factors conducive to foaming were statistically proved. Experiments run on more than 40 AS WWTP helped us to identify cause-effect relationships and useful methods to reduce foaming, varying with the type of dominant hydrophobic filamentous microorganisms. The finer points related to design and operation are identified in order to be effective against foaming. Depending on the type and degree of urgency of each case, different combat strategies are proposed.

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