Congreso: II Congreso Internacional Small Wat 07. Lugar de celebración: Sevilla Fecha: Octubre 2007

1. IDENTIFICATION OF FILAMENTOUS MICROORGANISMS IN ORGANIC
INDUSTRIAL ACTIVATED SLUDGE PLANTS.
E. Rodríguez1*, L. Isac 1, N. Fernández1, A. Zornoza1-2 and Mas, M3.
1
Grupo Bioindicación Sevilla (GBS), EDAR La Ranilla. Bda San José de Palmete s/n. Sevilla 41006. Dirección
Postal: AP 7279. Sevilla 41080. Teléfono/Fax: 955020847. g.b.s@lycos.es; www.grupobioindicacionsevilla.com
2
EDAR Quart-Benager (Valencia). Entidad Pública de Saneamiento de la Generalidad Valenciana (EPSAR). E-mail:
Azetazeta@hotmail.com
3
Hydrolab Microbiologica. c/ Blanco. Barcelona. 3808028. meritxellmas@hydrolabmicrobiologica.com
ABSTRACT
The microscopic observation and identification of filamentous bacteria, as well as its
distribution and quantification in industrial activated sludge, provide the plant operator with
useful information. In fact, most industrial wastewater treatment plants which suffer from
Bulking have operational disorders that can severely disrupt liquid-solid separation.
Keywords: Filamentous microorganisms; industrial wastewater treatment plant; Bulking
sludge; industrial wastewater; microscopic analysis; types of contaminants.
INTRODUCTION
In industrial wastewater treatment plants (IWTP), the use of microorganisms (bacteria, protists or metazoans)
as indicators of effluent quality is a practical control system that is getting increasingly popular in recent
years.
If an IWTP performance is good, its effluent can be re-used or released into the natural ecosystems without
running environmental risks. The capability of microorganisms population as indicators of effluent quality
has often been described in the literature.
The different types of industrial wastewaters effluents require different strategies to remove the
contaminants. It is known that the characteristics of industrial wastewaters from agriculture or food industry
are different from the characteristics of municipal wastewaters. On the ground, industrial wastewaters are
biodegradable and nontoxic, but they have higher concentrations of biochemical oxygen demand (BOD) and
suspended solids (SS).
The results shown are based on a comparative study carried out by GBS in several Spanish IWTPs. It has
been established that filamentous bacteria populations in industrial activated sludge differ significantly from
those in urban wastewater treatment plants.
Out of the twenty-seven samples analysed in this study, the presence of bulking was observed in 17 of them.
17 morphotypes were determined as dominant, according to the classification system proposed by
Eikelboom (2006) and Jenkins et al. (2004), based on the classification of the bacteria according to
morphotype, amongst which particularly noticeable were, in order of most frequent appearance: Type 021N,
Thiotrix sp. and Haliscomenobacter hydrossis. Out of the remainder of the plants analysed, 18% presented
problems of deflocculation and 4% presented phenomena of viscosity.
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2. MATERIAL AND METHODS
The populations of filamentous bacteria and the floccular structures in 27 Spanish IWTPs were studied. The
samples were taken from different industries, predominantly from the agroalimentary industry, as shown in
Table 1.
Table 1: No. of IWTPs studied, according to industrial sector.
MANUFACTURERS No OF IWTPs STUDIED
Milk production 5
Terpene manufacturer 1
Paper production 2
Beer production 3
Fat production 1
Metallurgy 1
Wine production 4
Citrus fruit production 1
Snack food production 1
Preserved vegetables 1
Flour production 3
Juice production 1
Tanneries 3
TOTAL 27
RESULTS AND DISCUSSION
Out of the 27 samples analysed, those from the agroalimentary industry predominated (85%). In general,
after different pre-treatments, industrial effluents are treated in the same way that urban wastewater.
However, the chemical industries, which are represented in this study by tanneries and metallurgical
industries (15%), produce toxic elements that make biological degradation difficult.
As for the agroalimentary industry, both the typical nutritional deficiency (Agridiotis et al., 2007), in which
nitrogen and phosphorous can limit degradation of organic material, and the chemical effluents loaded with
toxic agents, produce very poor flocculation; this poor flocculation affects both the respiration and
metabolism of the floc-forming bacteria. This process can be seen in the evaluation of the sludge samples
shown in figure 1 and in the microscopic evaluation of the sludge described in Table 2.
A B C D
Figure 1: The development of the active industrial sludge samples decanted into test tubes over
successive periods of 3 (A), 10 (B), 20 (C) and 30 (D) minutes.
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3. The results obtained indicate that the totality of the samples analysed, to a greater or lesser extent, presented
problems of deflocculation associated with toxins or nutritional deficiencies, which resulted in the
phenomena of filamentous bulking (63% of the samples studied), viscous bulking (4% of the samples
studied) and pin-point floc (27% of the samples studied).
Table 2: Microscopic evaluation of the structure of the flocs in the samples studied.
No OF SAMPLES
INDUSTRY FLOCULAR STRUCTURES
OBSERVED
Totally destructuration, pin-point floc,
Milk production 5
open-structured flocs and large-sized flocs
Terpene manufacture Defloculation and pin-point floc 1
No flocculation and large-sized flocs in a
Paper manufacture 2
mesh structure
Open-structured flocs and large flocs in a
Beer production 3
mesh structure
Fat production Large-sized flocs in a mesh structure 1
Pin-point floc and bad performance of the
Metallurgy 1
biological process
Large or medium-sized flocs, open-
Wine production structured flocs or dispersed flocs. Viscous 4
bulking.
Citrus fruit production Medium-sized flocs in a mesh structure 1
Snack food production Pin-point floc 1
Medium-sized flocs and open-structured
Canned vegetables 1
flocs in a mesh structure
Open-structured flocs, dispersed flocs.
Flour production 3
Predominantly, small-sized flocs.
Tanneries Dispersed flocs or lightly compacted flocs 3
Juice production Large-sized flocs in a mesh structure 1
In addition, the high biodegradability of the majority of the influents, practically all the samples (except
those from the metallurgical and tannery industry), created a situation of nutritional stress that made possible
the growth of filamentous bacteria to such an extent that flocculation was clearly inhibited, as illustrated by
the development of a slimy film, typical of T 0041, in conditions of nutritional stress. This situation can be
seen in Figure 2. The presence of these formations or slime coatings external to the filaments, were detected
in the samples analysed from the beer and citrus fruit producers.
A B C
Figure 2: (A) Indian ink test in which the filament type 0041 was observed, associated with nutritional deficiencies
(N/P); phase contrast 400x. (B) Abundant bacillary forms dispersed and near the structure of the flocs, retained by
abundant extra-cellular material; clear field, 1000x. (C) Appearance of the filament T 0041 (occasionally with a Neisser
positive coating) indicative of processes of nutritional deficiency. Citrus samples. Neisser stain. 1000x.
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4. The protozoan population present in the samples studied, which are affected to a great extent by floccular
formation, has been variable. Most of them presented a low diversity of species associated with small-sized
and open-structured flocs that only allowed the development of some swimming ciliates and impeded the
development of other groups such as crawling or sessile ciliates.
The definition of the dominant and secondary filamentous morphotypes has been the key feature in this
study. The results obtained are set out in Table 3.
Table 3: Dominant and secondary filament morphotypes observed, as well as the associated category numbers.
SECONDARY CATEGORY
INDUSTRY DOMINANT FILAMENT
FILAMENT NUMBER
Type 021N, Type 0675 and Type
Milk production 1 5
1702
Milk production 2 Type 0961 4
Type 0675, Type 021N and H.
Milk production 3 4
hydrossis
Milk production 4 Thiothrix and Type 1863 N. limicola 5
Thiothrix, Type 0803 and Type Type 1863, N. limicola and
Milk production 5 4
0211 Type 021N
Microthrix parvicella, Type
Terpen manufacture GALO 5
1863, Type 021N, N. limicola
Paper manufacture 1 Fibres/Deflocculation -
Paper manufacture 2 Fibres -
Beer production 1 Type 021N 3
Beer production 2 Type 021N and Type 0041 H. hydrossis and Type 0211 4
Type0211, H. hydrossis and Type
Beer production 3 3
0041
Fat production GALO 4
Metallurgy Deflocculation -
N. limicola and
Wine production 1 Type 021N and Thiothrix sp. 3
Haslicomenobacter hydrossis
Wine production 2 Thiothrix sp. and H.
Type 021N 4
hydrossis
Wine production 3 Viscous bulking -
Wine production 4 Thiothrix sp. Type 021N, N. limicola 4
H. hydrossis, Type 0041,
Citrus fruit production Type 021N Type 1701, N. limicola, 5
Thiothrix sp. and GALO
Snack food production Deflocculation -
N. limicola, Thiothrix sp. and
Canned vegetables Type 021N 5
GALO
Flour production 1 H. hydrossis and Type t021N Thiothrix sp. 5
Thiothrix,
Flour production 2 Type 021N Haliscomenobacter hydrossi 4
and Type 0411
Flour production 3 Thiothrix sp. and Type 0041 Type 021N and H. hydrossis 4
Thiothrix sp., Type 021N,
Tannery 1 GALO 3
and Type 0041
GALO, Thiothrix sp., and N.
Tannery 2 Type 021N 2
limicola
Tannery 3 Thiothrix sp., H. hydrossis N. limicola 4
Juice production Fungi 5
The morphotype that appeared as dominant on most occasions was the Type 021N, dominating in 31% of the
samples as can be seen in Table 5, followed by Thiothrix sp. in 17% of the samples.
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5. CONCLUSIONS
Although the biological treatment of industrial wastewater plays an essential role in minimising the impact
on the recipient rivers, it is still an unresolved issue for many industries.
We have established that changes in the flocculation process are widespread in the biological treatments of
most IWTPs and they have a lot to do with bulking and solids separation problems. So it is our belief that
trained professionals in microbiological control techniques (Bio-control) are needed to solve this sort of
problems.
Treatments such as chlorination, ozonisation, etc. can be useful to promptly control the biological problems
associated with these industrial wastewaters, but it is necessary to be aware of the effects of these treatments
and the rest of operational factors on the activated sludge, as well as the effects of nutrients and
micronutrients limitations.
The predominant morphotypes found were Type 021N and Thiotrix sp., as well as Haliscomenobacter
hydrossis, GALO and Type 0041, which usually make worse the problems caused by nutritional deficiency
and lack of oxygen in these IWTPs.
In order to optimise the treatment process of industrial effluents at the lowest cost, it is necessary to improve
our knowledge of the biota and the process of floculation in these IWTP. Further research is needed.
ACKNOWLEDGEMENTS
We would like to express our gratitude to the companies, organizations and associations to which we belong
and, especially, we thank EMASESA for their support.
REFERENCES
1. Agridiotis, V, Forster, C.F. y Cartiell-Marquet, C. (2007). Addition of Al and Fe salts during
treatment of paper mill effluents to improve activated sludge settlements characteristics. Bioresource
Technology 98, 15, 2926-2934.
2. Eikelboom, D. (2006). Identification and Control of Filamentous Micro-organisms in Industrial
Wastewater Treatment Plants. Multi-Media Training CD. IWA Publisingh. ISBN: 1843390965.
3. Jenkins, D., Richard, m. G. y Daigger, G. T. (2004). Manual on the Causes and Control of Activated
Sludge Bulking and Foaming. Lewis Publishers (Michigan).
4. Liu, Y. y Tay J-H. (2004). State of the art of biogranulation technology for wastewater treatment.
Biotechnology Advances 22, 533-563.
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