scholarly journals Evaluation of the accuracy of two simple methods for microscopic activated sludge analysis

2018 ◽  
Vol 78 (10) ◽  
pp. 2104-2112
Author(s):  
Mateusz Sobczyk ◽  
Agnieszka Pajdak-Stós ◽  
Edyta Fiałkowska ◽  
Wioleta Kocerba-Soroka ◽  
Joanna Starzycka-Giża ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Microscopic Analysis ◽  
Volume Index ◽  
Sign Test ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Effluent Quality ◽  
Significant Difference

Abstract Biological microscopic analysis is a popular method employed in wastewater treatment plants worldwide for evaluating activated sludge condition. However, many operators still have reservations regarding its reliability. In this study, we evaluated and compared two methods of microscopic sludge investigation: the sludge index (SI) and the Eikelboom–van Buijsen method (EB). We investigated 79 activated sludge samples from nine treatment plants located in southern Poland over a 1-year period. For each sample, sludge volume index values were calculated and compared with the results of evaluation made on the basis of microscopic analysis. Additionally, the effluent quality was analysed in 45 of 79 cases, including investigation of suspended solids, biochemical oxygen demand, chemical oxygen demand, total nitrogen and total phosphorous. The sign test and Wilcoxon matched pairs test showed that a significant difference existed between the two investigated methods. General conclusions from both methods do not provide reliable information concerning nitrogen and phosphorus removal. The EB method had a tendency to be more conservative in its general conclusions than the SI method. Both are highly reliable for estimating activated sludge quality and solid separation properties.

scholarly journals Efficiency and Technological Reliability of Contaminant Removal in Household WWTPs with Activated Sludge

2021 ◽  
Vol 11 (4) ◽  
pp. 1889 ◽  
Author(s):  
Agnieszka Micek ◽  
Krzysztof Jóźwiakowski ◽  
Michał Marzec ◽  
Agnieszka Listosz ◽  
Tadeusz Grabowski
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Treated Wastewater ◽  
Contaminant Removal ◽  
Nitrogen And Phosphorus ◽  
Wastewater Samples ◽  
Polish Law

The results of research on the efficiency and technological reliability of domestic wastewater purification in two household wastewater treatment plants (WWTPs) with activated sludge are presented in this paper. The studied facilities were located in the territory of the Roztocze National Park (Poland). The mean wastewater flow rate in the WWTPs was 1.0 and 1.6 m3/day. In 2017–2019, 20 series of analyses were done, and 40 wastewater samples were taken. On the basis of the received results, the efficiency of basic pollutant removal was determined. The technological reliability of the tested facilities was specified using the Weibull method. The average removal efficiencies for the biochemical oxygen demand in 5 days (BOD5) and chemical oxygen demand (COD) were 66–83% and 62–65%, respectively. Much lower effects were obtained for total suspended solids (TSS) and amounted to 17–48%, while the efficiency of total phosphorus (TP) and total nitrogen (TN) removal did not exceed 34%. The analyzed systems were characterized by the reliability of TSS, BOD5, and COD removal at the level of 76–96%. However, the reliability of TN and TP elimination was less than 5%. Thus, in the case of biogenic compounds, the analyzed systems did not guarantee that the quality of treated wastewater would meet the requirements of the Polish law during any period of operation. This disqualifies the discussed technological solution in terms of its wide application in protected areas and near lakes, where the requirements for nitrogen and phosphorus removal are high.

Influence of Hydraulic Loading Rate on Horizontal Zeolite Wetland Effluent Quality

2012 ◽  
Vol 573-574 ◽  
pp. 659-662
Author(s):  
Hao Wang
Keyword(s):  
Wastewater Treatment ◽  
Loading Rate ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Secondary Effluent ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Hydraulic Loading Rate ◽  
Effluent Quality ◽  
Hydraulic Loading

In Tangshan area, the secondary effluent of wastewater treatment plants was used for this study. Horizontal zeolite wetland was carried out treating it. Hydraulic loading rate was the parameters for analyzing the nitrogen and phosphorus removal efficiency of pollutants from the secondary effluent of wastewater treatment plant. Zeolite constructed wetlands showed different behaviors for nitrogen and phosphorus removals.Under the optimum hydraulic loading rate, the primary pollutions were removed to a large extent.

Occurrence of Microthrix parvicella in sequencing batch reactors

2014 ◽  
Vol 69 (10) ◽  
pp. 1984-1995 ◽  
Author(s):  
Lana Mallouhi ◽  
Ute Austermann-Haun
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Volume Index ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Municipal Wastewater Treatment ◽  
Nitrogen And Phosphorus ◽  
Microthrix Parvicella

Sequencing batch reactors (SBRs) are known for high process stability and usually have a good sludge volume index (SVI). Nevertheless, in many SBRs in Germany for municipal wastewater treatment, scum and foam problems can occur, and SVI can be larger than 200 mL/g. The microscopic investigations of the activated sludge from plants with nitrogen and phosphorus removal have shown that Microthrix parvicella is dominant in the activated sludge in most of them. Studies showed that the optimum growth of M. parvicella is performed at a high sludge age (>20 d) and low sludge load in the range of 0.05–0.2 kg of biochemical oxygen demand per kg of total suspended solids per day (kg BOD5/(TSS·d)). The investigations in 13 SBRs with simultaneous aerobic sludge stabilization (most of them are operated with a system called differential internal cycle strategy sequential batch reactor (DIC-SBR)) show that M. parvicella is able to grow in sludge loads less than 0.05 kg BOD5/(kg TSS·d) as well. To optimize the operation of those SBRs, long cycle times (8–12 h) and dosing of iron salts to eliminate long-chain fatty acids are both recommended. This leads to better SVI and keeps M. parvicella at a low frequency.

Effect of feed characteristics on the organic matter, nitrogen and phosphorus removal in an activated sludge system treating piggery slurry

2009 ◽  
Vol 60 (8) ◽  
pp. 2145-2152 ◽  
Author(s):  
C. González ◽  
P. A. García ◽  
R. Muñoz
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Oxygen Demand ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Piggery Wastewater ◽  
Efficient Treatment ◽  
Swine Slurry ◽  
Dissolved Phosphorus ◽  
Natural Water Bodies

Piggery wastewater is characterized by its high content in nitrogen and phosphorus, as well as by a low C/N ratio. This type of wastewater is traditionally spread to croplands (with its subsequent leaching to groundwater) or rarely discharged into natural water bodies, which ultimately cause severe episodes of eutrophication in aquatic ecosystems. In this context, activated sludge systems constitute a robust and efficient treatment option. The performance of an activated sludge process using a pre-denitrification configuration treating both sieved and flocculated swine slurry at a hydraulic retention time (HRT) of 7.7 days was evaluated. In order to avoid bacterial wash-out, sludge from the settler was recirculated to the anoxic tank to accomplish denitrification. Once the biomass was acclimatized, the reactor was fed with swine slurry containing 19, 2.6, and 0.27 g/L of total chemical oxygen demand (COD), total Kjeldhal nitrogen (TKN), and soluble P, respectively. Nitrogen removal showed a clear dependency on the influent composition. When the influent TKN/total COD and soluble COD/total COD ratios were respectively 0.12–0.15 and 0.7, the reactor exhibited good removal efficiencies (up to 99 and 91 for N-NH4+, TKN, respectively) while PO43− was removed up to 65%. However, when the influent TKN/total COD ratio rose to 0.26 and soluble COD/total COD decreased to 0.3, the denitrification process was severly hindered concomitant with and accumulation of nitrite. Nevertheless, organic matter degradation was not affected by influent composition. At the last stage of the experiment, removals of dissolved phosphorus fell to 40% when the redox potential (ORP) profile showed a constant value of −400 mV, likely due to phosphate released from bacterial slugde.

scholarly journals PENGARUH CO-PRECIPITATION BESI KLORIDA TERHADAP KINERJA LUMPUR AKTIF PADA PROSES PENGOLAHAN AIR LIMBAH DOMESTIK SINTETIK

REAKTOR ◽  
2015 ◽  
Vol 15 (3) ◽  
pp. 182
Author(s):  
Dian Fatikha Aristiami ◽  
I Nyoman Widiasa
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Suspended Solid ◽  
Volume Index ◽  
Sludge Volume Index ◽  
Mixed Liquor Suspended Solid ◽  
Effluent Quality ◽  
Co Precipitation ◽  
Settling Characteristics

The increase of population leads to an increase of the quantity of domestic wastewater. Activated sludge system is the most cost-efective to treat the domestic wastewater treatment. This study is aimed to evaluate the co-precipitation coagulant effect of FeCl3 on the growth of activated sludge, settling characteristics of the activated sludge, and effluent quality. sludge sedimentation characteristics (settling) as well as on the effluent quality. The activated sludge systems were operated in batch mode and synthetic domestic wastewaters with C:N:P ratio of 100:5:1 were used as feed wastewater. The growth of activated sludge was based on concentration of Mixed Liquor Suspended Solid (MLSS), settling characteristics of activated sludge was based on value of Sludge Volume Index (SVI), and effluent quality was based on turbidity, colour, N-ammonia concentration, and Chemical Oxygen Demand content. Results indicate that inhibition effect of FeCl3 to activated sludge activity was not significant at dosage ≤ 30 mg/L. Good settling characterisic (SVI 70-150 mg/L) was achieved at dosage of 20-30 mg/L. Finally, the best effluent quality, i.e. turbidity (9.4), colour (96), amonia removal (83.6%), and COD removal (72.97%), at dosage of 30 mg/L. Keywords: activated sludge; co-precipitation; domestic wastewater; wastewater treatment Abstrak Peningkatan jumlah penduduk mengakibatkan kenaikan jumlah air limbah domestik. Sistem lumpur aktif merupakan proses yang paling efektif untuk mengolah air limbah domestik. Penelitian ini bertujuan untuk mengevaluasi pengaruh co-precipitation koagulan FeCl3 terhadap pertumbuhan lumpur aktif, karakteristik pengendapan lumpur aktif, dan kualitas efluen. Sistem lumpur aktif dioperasikan secara curah dan umpan air limbah yang digunakan adalah air limbah domestik sintesis dengan rasio C:N:P = 100:5:1. Pertumbuhan lumpur aktif  berdasarkan konsentrasi Mixed Liquor Suspended Solid (MLSS), karakteristik pengendapan lumpur berdasarkan  nilai Sludge Volume Index (SVI), dan kualitas efluen berdasarkan tingkat kekeruhan, warna, kadar N-amonia dan kadar Chemical Oxygen Demand (COD). Hasil penelitian menunjukkan bahwa inhibisi FeCl3 terhadap aktivitas lumpur aktif tidak signifikan pada dosis ≤ 30 mg/L. Karakteristik pengendapan yang baik (SVI 70-150 mg/L) tercapai pada dosis 20-30 mg/L. Kualitas efluen terbaik, yaitu  kekeruhan (9,4),  warna (96), penyisihan amonia (83,6%) dan penyisihan COD (72,97%), pada dosis 30 mg/L. Kata kunci: lumpur aktif; co-precipitation; air limbah domestik; pengolahan air limbah  

Integrated side-stream reactor for biological nutrient removal and minimization of sludge production

2015 ◽  
Vol 71 (7) ◽  
pp. 1056-1064 ◽  
Author(s):  
M. Coma ◽  
S. Rovira ◽  
J. Canals ◽  
J. Colprim
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Biological Nutrient Removal ◽  
Slight Reduction ◽  
Nitrogen And Phosphorus ◽  
Effluent Quality ◽  
Side Stream ◽  
Sludge Production

Integrated processes to reduce in situ the sludge production in wastewater treatment plants are gaining attention in order to facilitate excess sludge management. In contrast to post-treatments, such as anaerobic digestion which is placed between the activated sludge system and dewatering processes, integrated technologies are placed in the sludge return line. This study evaluates the application of an anoxic side-stream reactor (SSR) which creates a physiological shock and uncouples the biomass metabolism and diverts the activity from assimilation for biosynthesis to non-growth activities. The effect of this system in biological nutrient removal for both nitrogen and phosphorus was evaluated for the anaerobic, anoxic and aerobic reactors. The RedOx potential within the SSR was maintained at −150 mV while the sludge loading rate was modified by increasing the percentage of recycled activated sludge feed to the SSR (0 and 40% at laboratory scale and 0, 10, 50 and 100% at pilot scale). The use of the SSR presented a slight reduction of phosphorus removal but maintained the effluent quality to the required discharge values. Nitrogen removal efficiency increased from 75 to 86% while reducing the sludge production rate by 18.3%.

Considerations in the Process Design of Nutrient Removal Activated Sludge Processes

1983 ◽  
Vol 15 (3-4) ◽  
pp. 283-318 ◽  
Author(s):  
G A Ekama ◽  
I P Siebritz ◽  
G V R Marais
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Concentration Ratio ◽  
Oxygen Demand ◽  
Biological Nutrient Removal ◽  
Nitrogen And Phosphorus ◽  
Effluent Quality ◽  
Biological Nitrogen ◽  
Activated Sludge Processes ◽  
P Removal

The average influent wastewater characteristics - (i) the COD concentration, (ii) the TKN/COD concentration ratio, (iii) the rapidly biodegradable COD concentration, (iv) the maximum specific growth rate of the nitrifiers at 20°C attainable in the wastewater, (v) the maximum and minimum temperatures, and (vi) the P/COD concentration ratio - are shown to govern the design of, and effluent quality from single sludge activated sludge processes for both biological nitrogen and phosphorus removal. The TKN/COD ratio governs the selection of the process type: For the Phoredox process, complete denitrification is essential to obtain excess P removal, and this is shown to be feasible only for TKN/COD ratios less than 0,07 to 0,08 mgN/mgCOD; as the TKN/COD ratio increases above 0,08, complete denitrification becomes increasingly unlikely, and the UCT or Modified UCT processes are appropriate because in these processes complete denitrification is not essential to achieve excess P removal - in these processes N and P removal can be traded off against each other depending on the critical nutrient to be removed. Primary sedimentation significantly reduces the biological nutrient removal potential of activated sludge process because it increases the TKN/COD and P/COD ratios and reduces the COD load; however it significantly reduces the process volume and total oxygen demand.

Nitrogen and Phosphorus Removal by Activated Sludge Process: A Review

2017 ◽  
Vol 14 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Zhengan Zhang ◽  
Shulin Pan ◽  
Fei Huang ◽  
Xiang Li ◽  
Juanfang Shang ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Activated Sludge Process ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal

New German design guideline for single stage activated sludge plants

2000 ◽  
Vol 41 (9) ◽  
pp. 139-145
Author(s):  
R. Kayser
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Design Procedure ◽  
Single Stage ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Design Guideline

The German design guideline A 131 “Design of single stage activated sludge plants” was amended in 1999. The main changes of the guideline from 1991 are outlined. The design procedure for plants with nitrogen and phosphorus removal is presented.

scholarly journals Influent with Particulate Substrate, Clean, Innocuous and Sustainable Solution for Bulking Control and Mitigation in Activated Sludge Process

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 984
Author(s):  
Pedro Cisterna-Osorio ◽  
Claudia Calabran-Caceres ◽  
Giannina Tiznado-Bustamante ◽  
Nataly Bastias-Toro
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Nutrient Deficiency ◽  
Microscopic Analysis ◽  
Volume Index ◽  
Favorable Effect ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Active Sludge ◽  
Chemical Reagents

This research studies the incidence of the type of substrate, soluble or particulate, in the emergence, development, and inhibition of bulking in activated sludge systems. It was evaluated using the sludge volume index (SVI), mixing liquor-suspended solids (MLSS), microscopic analysis of biomass, and effluent suspended solids (ESS). In the first experiment, four sequencing batch reactors (SBRs) were fed with soluble substrate at a fixed mass, while the mass of the particulate substrate varied, as those (saccharose mass/flour mass) ratios were 3:1, 3:2, 3:3 and 3:4., with a deficit ranging from 20 to 30% compared to the ratio recommended. The four SBRs have similar MLSS, IVL, and ESS. From day 30, with a deficit from 80 to 90%, the influents have ratios 1/1 and 1/2 until 48 days. The SBRs present IVL between 600 and 730 mL/g and ESS from 370 to 440 mg/L; unlike influents with ratios 1/3 and 1/4, they present IVL between 170 and 185 mL/g, and ESS from 260 to 270 mg/L. The favorable effect of particulate matter is categorical. In the second set of experiments, two SBRs were studied: SBR 1 fed with saccharose, and SBR 2 with flour; there is a lack of nutrients causing bulking in SBRs. Once the nutrient deficiency condition is changed in day 11 to excess, after 22 days, the SVI was 190 mL/g, ESS was 360 mg/L, and MLSS was 2000 mg/L for influents with saccharose; the influent with flour, with an SVI of 80 mL/g, ESS of 100 mg/L, and MLSS of 4000 mg/L, shows faster and more consistent recovery with the particulate substrate. Therefore, the proposal is to add particulate substrate-like flour to active sludge plants facing bulking. It is a clean, innocuous and sustainable alternative to processes that use chemical reagents.

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