Application of quantitative RT-PCR to determine the distribution of Microthrix parvicella in full-scale activated sludge treatment systems

Foaming incidents in activated sludge treatment plants are a worldwide problem and occur on a regular basis in both municipal and industrial activated sludge treatment plants. Foaming is most often caused by excessive growth of filamentous bacteria, especially the gram-positive ones affiliated within the Actinobacteria, e.g. the branched Mycolata or CandidatusMicrothrix parvicella. Previous studies have shown that populations of Microthrix can be controlled by addition of certain polyaluminium compounds, but until now no effective chemicals have been identified to control other important foam formers such as the Mycolata. A new chemical (FilamentEx, FEX-120) was tested in full-scale in a Swedish wastewater treatment plant (WWTP) with immense foaming problems. In total, three different dosing events were carried out for more than 1 year. After only 8–17 weeks in each period, all foam had disappeared, and dosing of FEX-120 was stopped. Another 11 full-scale WWTPs in different countries were treated with FEX-120 because of severe Mycolata foaming on process tanks. In nine out of 11 plants, where the causative organisms were Gordonia or Skermania, a significant reduction of foam up to 100% was observed after treatment for approx. 10 weeks. In two WWTPs with unknown Mycolata organisms, no reduction was observed.

Download Full-text

Full‐scale study of activated sludge treatment of low strength municipal wastewater

International Journal of Environmental Studies ◽

10.1080/00207239208710751 ◽

1992 ◽

Vol 41 (1-2) ◽

pp. 121-132

Author(s):

Yung‐Tse Hung ◽

Howard H. Lo

Keyword(s):

Activated Sludge ◽

Municipal Wastewater ◽

Full Scale ◽

Sludge Treatment ◽

Low Strength

Download Full-text

Biological Nutrient Removal of Nitrogen Using Cyclic Aeration: Application in a Full-Scale Activated Sludge Treatment Plant

Proceedings of the Water Environment Federation ◽

10.2175/193864710798158184 ◽

2010 ◽

Vol 2010 (17) ◽

pp. 742-756

Author(s):

Jennifer Ruddy ◽

Say K. Ong ◽

Keith Hobson ◽

Phil Koundakjian ◽

Jim Buck

Keyword(s):

Activated Sludge ◽

Nutrient Removal ◽

Treatment Plant ◽

Full Scale ◽

Biological Nutrient Removal ◽

Sludge Treatment

Download Full-text

Bench-Scale Testing of Activated Sludge Treatment for a TMP Wastewater

Water Quality Research Journal ◽

10.2166/wqrj.1993.030 ◽

1993 ◽

Vol 28 (3) ◽

pp. 571-596 ◽

Cited By ~ 1

Author(s):

Susan F. Liver ◽

Henry K. Miyamoto ◽

Steve A. Black

Keyword(s):

Activated Sludge ◽

Full Scale ◽

Operating Conditions ◽

Cold Weather ◽

Sludge Treatment ◽

Bench Scale ◽

Conventional Activated Sludge ◽

Initial Batch ◽

Treated Effluent ◽

Biokinetic Parameters

Abstract A continuous bench-scale treatability study determined the most desirable design and operating parameters for waste treament of effluent from an integrated Canadian TMP newsprint operation. An initial batch study indicated that the effluent was biologically treatable and provided initial biological kinetic (biokinetic) parameters for this wastewater. This information was used to design the continuous study. Conventional activated sludge treatment of the mill wastewater can produce an effluent which meets the federal regulations for BOD5, suspended solids, and toxicity to D. magna. Predictions using cumulative toxicity units (CTU) indicate that the treated effluent would also be non-toxic to O. mykiss as well. Analyses of ammonia in the treated effluent indicated that un-ionized ammonia concentrations would be non-toxic to rainbow trout. Mass balances incorporating the results of the bench-scale studies and the effect of fibre carry-over from the primary clarifier, defined the full-scale operating conditions selected as: an F/M of 0.35 d−1, HRT of 0.5 days, SRT of 6 days and an MLSS of 4400 mg/L (when no polymer is used at the primary clarifier). These conditions were arrived at by selecting the smallest HRT which still corresponded to an MLSS < 5000 mg/L, an F/M < 0.4 d−1 and an SRT > 5 days. Based on the kinetics for biological treatment of mill effluent, at the maximum mill production, adequate BOD5 removal will still easily be obtained under the above operating conditions, even during cold weather periods. Operational concerns identified by bench-scale testing indicated that a full-scale facility should incorporate an anoxic selector (although the anoxic selector did not show measurable improvement in the bench-scale tests) and micronutrient addition for filamentous bulking control.

Download Full-text

Plant-wide Optimization of a Full-Scale Activated Sludge Plant with Anaerobic Sludge Treatment

IFAC-PapersOnLine ◽

10.1016/j.ifacol.2015.09.137 ◽

2015 ◽

Vol 48 (8) ◽

pp. 1234-1239 ◽

Cited By ~ 4

Author(s):

C. Puchongkawarin ◽

S. Fitzgerald ◽

B. Chachuat

Keyword(s):

Activated Sludge ◽

Full Scale ◽

Anaerobic Sludge ◽

Sludge Treatment

Download Full-text

Nitrous oxide emissions and dissolved oxygen profiling in a full-scale nitrifying activated sludge treatment plant

Water Research ◽

10.1016/j.watres.2012.10.004 ◽

2013 ◽

Vol 47 (2) ◽

pp. 524-534 ◽

Cited By ~ 93

Author(s):

Amina Aboobakar ◽

Elise Cartmell ◽

Tom Stephenson ◽

Mark Jones ◽

Peter Vale ◽

...

Keyword(s):

Nitrous Oxide ◽

Dissolved Oxygen ◽

Activated Sludge ◽

Treatment Plant ◽

Full Scale ◽

Nitrous Oxide Emissions ◽

Sludge Treatment

Download Full-text

Influence of temperature and sludge loading on activated sludge settling, especially on Microthrix parvicella

Water Science & Technology ◽

10.2166/wst.1998.0573 ◽

1998 ◽

Vol 37 (4-5) ◽

pp. 27-35 ◽

Cited By ~ 30

Author(s):

S. Knoop ◽

S. Kunst

Keyword(s):

Wastewater Treatment ◽

Low Temperature ◽

Activated Sludge ◽

Municipal Wastewater ◽

Loading Rate ◽

Wastewater Treatment Plants ◽

Full Scale ◽

Causative Organism ◽

Foam Formation ◽

Microthrix Parvicella

During recent years modern full scale wastewater treatment plants with biological nitrification, denitrification and phosphorus removal have had increasing problems with foam formation on the surfaces of aerobic tanks and with bulking activated sludge. The results of a survey in 1995 (Kunst and Knoop, 1996) showed that most often the filamentous bacterium Microthrix parvicella is responsible for these problems. Up to today there is only little knowledge about its selection criteria in activated sludge. Therefore several experiments were done in full scale activated sludge plants and in laboratory systems under defined conditions to investigate the influence of low (< 0.1 kg/(kg·d)) and high (≤ 0.2 kg/(kg·d)) BOD5-sludge loading rates on the growth and morphology of M. parvicella and the settlement of activated sludge. Furthermore the influence of temperatures of 5°C, 12°C and 20°C on the growth of M. parvicella was investigated. It was shown that M. parvicella grows at low BOD5-sludge loading rate and low temperature and is the main causative organism of bulking and foaming sludge in nutrient removal plants. On the basis of this investigation it was concluded that the growth of M. parvicella and the settling problems of the activated sludge resulting from excessive growth of this filament will always appear in modern municipal wastewater treatment plants with BOD5-sludge loading rate ≤ 0.1 kg/(kg·d) especially under low temperature conditions.

Download Full-text

The influence of PAX-14 on activated sludge systems and in particular on Microthrix parvicella

Water Science & Technology ◽

10.2166/wst.2002.0521 ◽

2002 ◽

Vol 46 (1-2) ◽

pp. 487-490 ◽

Cited By ~ 25

Author(s):

T. Roels ◽

F. Dauwe ◽

S. Van Damme ◽

K. De Wilde ◽

F. Roelandt

Keyword(s):

Activated Sludge ◽

Nutrient Removal ◽

Wastewater Treatment Plants ◽

Full Scale ◽

Morphological Properties ◽

Eu Directive ◽

Solids Separation ◽

Microthrix Parvicella ◽

Separation Problems ◽

Activated Sludge Systems

The amount of wastewater treatment plants (WWTP) dealing with solid separation problems has significantly increased since the new requirements of the EU Directive 271/91 on nutrient removal. In Flanders a number of the nutrient removal WWTP are affected by solid separation problems mostly attributed to Microthrix parvicella being the most common dominant species. The effect of dosing polyaluminium chloride (PAX-14) on activated sludge is illustrated for WWTP solids separation problems, in particular because of Microthrix parvicella. The effects of the addition of PAX-14 on the microbiology and the morphology of Microthrix parvicella were studied in 9 full-scale WWTPs. PAX-14 succeeded in reducing high SVI-values and controlled foaming problems whenever caused by Microthrix parvicella. Laboratory trials have shown that the dosage of PAX-14 should be less than 150 μL/L or 7 g Al3+/kg MLSS. At a dosage higher than 250 μL/L, an increase of free bacteria and a decrease of the protozoa activity are observed. In full-scale, PAX-14 is dosed at a concentration of 1.5 to 4.5 g Al3+/kg MLSS. Before addition, the mixed liquor scum layer – if present – should be removed. In our experience, the dosing should last for at least 3 weeks. During the first week, no drastic changes occur. At the end of the first week, an increase of SS and SVI is possible. The SVI and scum start to decrease after 10 to 15 days. The amount of filaments is reduced after 3 to 3½ weeks. The morphological properties of Microthrix parvicella change, while other filaments such as Nostocoida limicola and Nocardia spp. are not affected. This study proves that PAX-14 is effective in controlling bulking and foaming problems at WWTPs when they are due to Microthrix parvicella. Prediction of when the SVI will decrease and when addition should be stopped is possible.

Download Full-text