The Effect of Controlled pH on the Development of Rosette-Forming Bacteria in Axenic Culture and Bulking Activated Sludge

An infestation of a rosette-forming microorganism, with morphological characteristics bearing some resemblance to Eikelboom type 021N and Thiothrix spp., occurred in the activated sludge process of a paper and pulp manufacturing facility during the autumn of 1986. The microorganism could not be eliminated by periodic acid-shocking of the mixed liquor with sulfuric acid, however, exposure of the mixed liquor solids for 10 days at controlled pH (circum pH 5.5) brought almost immediate lowering of the sludge volume index and effluent suspended solids to levels observed in normal operations. The bulking correction technique required no purchase of special chemicals in that the procedure was a mere modification of the liming step normally employed to bring the natural pH of the wastewater (pH 3) to a level suitable for the practice of biological treatment.

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Characteristics of developed granules containing selected decolourising bacteria for the degradation of textile wastewater

Water Science & Technology ◽

10.2166/wst.2010.021 ◽

2010 ◽

Vol 61 (5) ◽

pp. 1279-1288 ◽

Cited By ~ 15

Author(s):

Z. Ibrahim ◽

M. F. M. Amin ◽

A. Yahya ◽

A. Aris ◽

K. Muda

Keyword(s):

Biological Treatment ◽

Morphological Characteristics ◽

Industrial Effluents ◽

Textile Wastewater ◽

Treatment Method ◽

Current Treatment ◽

Volume Index ◽

Biological Processes ◽

Initial Ranging ◽

Maximum Removal

Textile wastewater, one of the most polluted industrial effluents, generally contains substantial amount of dyes and chemicals that will cause increase in the COD, colour and toxicity of receiving water bodies if not properly treated. Current treatment methods include chemical and biological processes; the efficiency of the biological treatment method however, remains uncertain since the discharged effluent is still highly coloured. In this study, granules consisting mixed culture of decolourising bacteria were developed and the physical and morphological characteristics were determined. After the sixth week of development, the granules were 3–10 mm in diameter, having good settling property with settling velocity of 70 m/h, sludge volume index (SVI) of 90 to 130 mL/g, integrity coefficient of 3.7, and density of 66 g/l. Their abilities to treat sterilised raw textile wastewater were evaluated based on the removal efficiencies of COD (initial ranging from 200 to 3,000 mg/L), colour (initial ranging from 450 to 2000 ADMI) of sterilised raw textile wastewater with pH from 6.8 to 9.4. Using a sequential anaerobic-aerobic treatment cycle with hydraulic retention time (HRT) of 24 h, maximum removal of colour and COD achieved was 90% and 80%, respectively.

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Chemical Neutralization of Alkaline Wastewater During Activated Sludge Treatment

Water Quality Research Journal ◽

10.2166/wqrj.1970.006 ◽

1970 ◽

Vol 5 (1) ◽

pp. 80-101 ◽

Cited By ~ 1

Author(s):

Jerzy Ganczarczyk

Keyword(s):

Activated Sludge ◽

Biological Treatment ◽

Kraft Pulp ◽

Pulp Mill ◽

Total Alkalinity ◽

Sludge Treatment ◽

Mixed Liquor ◽

Kraft Pulp Mill ◽

Ph Values ◽

Practical Limit

Abstract The chemical neutralization of alkaline wastewater during the activated sludge treatment is due mostly to the development of CO2 during such biological treatment. The full-scale activated sludge treatment of alkaline wastewater without preliminary separate chemical neutralization was studied for the case of an unbleached Kraft pulp mill effluent. The treatment was carried out in limited-mixing aeration tanks at conventional loadings. Maximum pH values of the mixed liquor were 10.2, and the corresponding total alkalinity values reached 23.8 me/l. It was observed that considerable parts of the waste-water alkalinity were removed during the initial periods of mixed liquor aeration. The practical limit of this type of neutralization seems to be close to pH of 8.

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Operating Experiences at Low Solids Retention Time

Water Science & Technology ◽

10.2166/wst.1984.0035 ◽

1984 ◽

Vol 16 (12) ◽

pp. 661-672 ◽

Cited By ~ 1

Author(s):

T E Wilson ◽

W A Ambrose ◽

H O Buhr

Keyword(s):

Activated Sludge ◽

Retention Time ◽

Suspended Solids ◽

Volume Index ◽

Sludge Volume Index ◽

Effluent Quality ◽

Mixed Liquor ◽

Solids Retention Time ◽

Solids Retention ◽

Typically Achieving

Five full scale activated sludge plants have been operated at low solids retention time (SRT, monthly averages as low as 0.8 days) and mixed liquor suspended solids (MLSS, monthly averages as low as 500 mg/l) values for 2 to 3 years. Operating results for this period are compared to 3 to 3-1/2 years of operation at conventional, higher, SRT and MLSS values. The data show that the lower SRT operation provided better effluent quality, typically achieving less than 15 mg/l of BOD5 or suspended solids, while not significantly increasing either the total (dry) sludge production or the sludge volume index (SVI). These data indicate that plants can be built and operated using significantly smaller tankage than conventionally accepted.

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Microbial community analysis of a laboratory-scale biological process for the treatment of vegetable oil effluent

10.51415/10321/733 ◽

2011 ◽

Author(s):

◽

Adrian Phillip Degenaar

Keyword(s):

Microbial Community ◽

Activated Sludge ◽

Biological Treatment ◽

Biological Process ◽

Blot Hybridization ◽

Laboratory Scale ◽

Dot Blot ◽

Mixed Liquor ◽

Dot Blot Hybridization ◽

Alpha Proteobacteria

Untreated vegetable oil effluents (VOEs) are known for creating shock-loading problems for the receiving wastewater treatment installations, resulting in poor quality final effluents being produced which do not satisfy municipal discharge standards. Onsite activated sludge treatment as an alternative has not been fully investigated. Hence, in this investigation biological treatment using the activated sludge process was chosen as the method for the treatment of VOE. The effect of VOE on measured process parameters was also determined. Novel molecular techniques such as fluorescent in situ hybridisation (FISH) and dot-blot hybridization have become powerful tools for the analysis of complex microbial communities that exist within activated sludge. The aim of this investigation was to evaluate biological treatment, optimize and apply FISH and dot-blot hybridization in order to analyze the microbial community implicated the biological treatment of VOE using probes EUBmix, ALF1b, BET42a, GAM42a and HGC69a. A laboratory-scale modified Ludzack-Ettinger (MLE) process setup and fed VOE with a COD (chemical oxygen demand) of ± 1000 mg/L. Daily monitoring of the process involved COD and TKN (total kjeldahl nitrogen) analysis of the influent and effluent as well as direct OUR (oxygen utilization rate) measurement and monitoring of the MLVSS (mixed liquor volatile suspended solids) concentration of the aerobic mixed liquor. The process exhibited overall COD and TKN removal capacities of 84% and 90% respectively. The aerobic mixed liquor had an OUR of 19 mgO/L.h and an average MLVSS concentration of 3000 mg/L. FISH results revealed that 72% of cells stained with 4‟, 6-diamidino-2-phenylindole (DAPI) within the aerobic mixed liquor bound to probe EUBmix, indicating a substantial Bacterial population within the laboratory-scale biological process. The alpha-Proteobacteria was identified as the dominant bacterial community comprising 31% of Bacterial cells, followed by the beta-Proteobacteria (17% of EUBmix), gamma-Proteobacteria (8% of EUBmix) and Actinobacteria (4% of EUBmix). Results of dot-blot hybridization were in agreement with FISH Adrian Phillip Degenaar| CHAPTER 1: General Introduction - v - results reiterating dominance of the alpha-Proteobacteria. This indicated that the class alpha-Proteobacteria could play a primary role in the biological degradation of VOE. This research will therefore aid in process design and retrofitting of biological processes treating VOE.

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The effects of high salinity on nitrogen removal and the formation characteristics of aerobic granular sludge

Environmental Engineering Research ◽

10.4491/eer.2019.233 ◽

2019 ◽

Vol 25 (5) ◽

pp. 659-667 ◽

Cited By ~ 3

Author(s):

HyunGu Kim ◽

DaeHee Ahn

Keyword(s):

Microbial Community ◽

Removal Efficiency ◽

Biological Treatment ◽

High Salinity ◽

Granular Sludge ◽

Suspended Solid ◽

Microbial Community Analysis ◽

Volume Index ◽

Aerobic Granular Sludge ◽

Mixed Liquor

This study investigated the biological treatment of high-salinity wastewater using aerobic granular sludge (AGS). The removal performance, AGS characteristics, and microbial community were examined under salinity conditions ranging from 0.5 to 3.0 wt.%. When the salinity was increased, the removal efficiency of the chemical oxygen demand did not change substantially. The mean removal efficiency of NH4+-N ranged from 43.7 to 72.6% during the operation period. As for the concentration of extracellular polymeric substances (EPS), the polysaccharide/protein (PS/PN) ratio increased from 0.37 to 0.57. The concentrations of the mixed liquor suspended solid (MLSS) and mixed liquor volatile suspended solid (MLVSS) were 4,560 and 3,170 mg/L, respectively, in the end phase, and the MLVSS/MLSS ratio decreased from 0.81 to 0.69. The sludge volume index (SVI30) decreased linearly from 88 to 58 mL/g. In the microbial community analysis, Nitrosomonas species accounted for 22.9% of the total bacteria in the initial phase, whereas Halomonas accounted for 43.2% in the end phase. Hence, the gradually increased salinity appears to facilitate the dominance of halophilic microorganisms in the long-term operation of an AGS-based biological treatment system and the stable retention of AGS.

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Complete solids retention activated sludge process

Water Science & Technology ◽

10.2166/wst.2015.614 ◽

2015 ◽

Vol 73 (6) ◽

pp. 1364-1370 ◽

Cited By ~ 2

Author(s):

E. Amanatidou ◽

G. Samiotis ◽

E. Trikoilidou ◽

G. Pekridis ◽

L. Tsikritzis

Keyword(s):

Activated Sludge ◽

Suspended Solids ◽

Treatment Plant ◽

Morphological Characteristics ◽

Utilization Rate ◽

Growth Phases ◽

Predator Species ◽

Operational Conditions ◽

Mixed Liquor ◽

Solids Retention

In a slaughterhouse's full-scale extended aeration activated sludge wastewater treatment plant (WWTP), operating under complete solids retention time, the evolution of mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) concentration, food to micro-organisms ratio (F/M) and substrate utilization rate (SUR) were studied for over a year. Biomass growth phases in correlation to sludge biological and morphological characteristics were studied. Three distinguished growth phases were observed during the 425 days of monitoring. The imposed operational conditions led the process to extended biomass starvation conditions, minimum F/M, minimum SUR and predator species growth. MLSS and MLVSS reached a stabilization phase (plateau phase) where almost zero sludge accumulation was observed. The concept of degradation of the considered non-biodegradable particulate compounds in influent and in biomass (cell debris) was also studied. Comparison of evolution of observed sludge yields (Yobs) in the WWTP with Yobs predictions by activated sludge models verified the degradation concept for the considered non-biodegradable compounds. Control of the sedimentation process was achieved, by predicting the solids loading rate critical point using state point analysis and stirred/unstirred settling velocity tests and by applying a high return activated sludge rate. The nitrogen gas related sedimentation problems were taken into consideration.

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Pembuatan Pilot Project Pengolahan Air Limbah Industri Rambut Palsu dengan Sistem Lumpur Aktif

Jurnal Riset Teknologi Industri ◽

10.26578/jrti.v8i15.1551 ◽

2016 ◽

Vol 8 (15) ◽

pp. 37-47

Author(s):

Sri Moertinah ◽

Misbachul Moenir

Keyword(s):

Activated Sludge ◽

Biological Treatment ◽

Operating Cost ◽

Pilot Project ◽

Labor Costs ◽

Industrial Waste Water ◽

Microbial Adaptation ◽

Central Java ◽

Electricity Costs

This study aims to create a pilot project for wastewater treatment wig industry with biological activated sludge technology to applied in the industry. Design criteria for the pilot project are the influent COD ≤ 900 mg/l, MLSS = 3,000 mg/l, 30-hours residence time. DO ≥ 2 mg/l and flow 10 m3/day. Implementation of a pilot project initiated by seeding aerobic microbes and microbial adaptation to proceed with wastewater to be treated. The trial results showed that the pilot project % COD reduction ranged from 73.2% - 91% and the result is not much different from the results of laboratory-scale research about 89.7% and the quality of the effluent is already fullfill the standard of industrial waste water wig required by the Central Java Provincial Regulation No. 5 of 2012. The calculation of operating cost of activated sludge biological treatment which includes labor costs, electricity costs, equipment maintenance costs, expenses and other nutrients obtained the price of Rp. 2972/m3 or Rp. 742.99/wig.ABSTRAKPenelitian ini bertujuan untuk membuat pilot project pengolahan air limbah industri rambut palsu dengan sistem lumpur aktif yang diterapkan di industri. Kriteria desain pilot project tersebut adalah COD influen ≤ 900 mg/l, MLSS = 3.000 mg/l, waktu tinggal 30 jam DO≥2 mg/l dan debit air limbah 10 m3/hari. Pelaksanaan pilot project dimulai dengan seeding mikroba aerob dan dilanjutkan dengan adaptasi mikroba dengan air limbah yang akan diolah. Hasil uji coba pilot project menunjukkan bahwa % penurunan COD berkisar antara 73,2% - 91% dan hasil ini tidak berbeda jauh dengan hasil penelitian skala laboratorium sekitar 89,7% dan kualitas air limbah hasil pengolahan sudah memenuhi baku mutu air limbah industri rambut palsu yang dipersyaratkan oleh Peraturan Daerah Provinsi Jawa Tengah No 5 tahun 2012. Dari hasil perhitungan biaya operasional pengolahan biologis lumpur aktif yang meliputi biaya tenaga kerja, biaya listrik, biaya perawatan peralatan, biaya nutrien dan lainnya diperoleh harga sebesar Rp. 2972/m3 atau Rp. 742,99/wig. Kata kunci : air limbah industri rambut palsu, pilot project, sistem lumpur aktif

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On-line measurements of settling characteristics in activated sludge

Water Science & Technology ◽

10.2166/wst.1997.0144 ◽

1997 ◽

Vol 36 (4) ◽

pp. 307-312

Author(s):

Michael R. Rasmussen ◽

Torben Larsen

Keyword(s):

Activated Sludge ◽

Settling Velocity ◽

Continuous Measurement ◽

Batch Reactor ◽

Volume Index ◽

Sludge Volume Index ◽

Dynamic Variations ◽

On Line ◽

Settling Column ◽

Settling Characteristics

An on-line settling column for measuring the dynamic variations of settling velocity of activated sludge has been developed. The settling column is automatic and self-cleansing insuring continuous and reliable measurements. The settling column was tested on sludge from a batch reactor where sucrose was added as an impulse to activated sludge. The continuous measurement of settling velocity revealed a highly dynamic response after the sucrose was added. The results were verified with simultaneous measurement of the initial settling rate. A 200 hour experiment showed variations in settling velocity, which was not apparent in the DSVI (Diluted Sludge Volume Index).

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