scholarly journals Causes and remedies for filamentous foaming in activated sludge treatment plant

2014 ◽  
Vol 16 (4) ◽  
pp. 762-772 ◽  

<p>This paper reviews the problem of foaming associated with the activated sludge process and its control using various physical, chemical and biological methods. Activated sludge process is widely used for treatment of every type of wastewater like industrial, domestic and municipal wastewater. This process is driven by a complex microbial population, among which some mycolic acid containing bacteria leads to the stable foam formation which ultimately results in poor efficiency of the plants and leading to major environmental, operational, and health problems. A number of researches provide the evidences of foaming in wastewater treatment plants and its control using physical, chemical and biological methods. Current approaches for controlling foam includes operational adjustments, additional structures, controlling dissolved oxygen levels, water sprays, steam application, polymer addition, chlorination and a novel and ecofriendly approach that is treatment of filamentous bacteria with the specific phages. A detailed study of all methods is presented and collectively described in this review paper for a better understanding of the foam controlling strategies.&nbsp;</p>

2003 ◽  
Vol 47 (11) ◽  
pp. 165-172 ◽  
Author(s):  
N. Kreuzinger ◽  
A. Farnleitner ◽  
G. Wandl ◽  
R. Hornek ◽  
R. Mach

Incomplete nitrification at an activated sludge plant for biological pre-treatment of rendering plant effluents led to a detailed investigation on the origin and solution of this problem. Preliminary studies revealed that an inhibition of ammonia oxidising microorganisms (AOM) by process waters of the rendering plant was responsible for the situation. We were able to show a correlation between the existence of specific AOM and nitrification capacity expressed as oxygen uptake rate for maximal nitrification (OURNmax). Only Nitrosospira sp. was found in the activated sludge of the rendering plant and another industrial wastewater treatment plant with problems in nitrification, while reference plants without nitrification problems showed Nitrosomonas spp. as the predominant ammonia oxidising bacteria. By accompanying engineering investigations and experiments (cross-feeding experiments, operation of a two-stage laboratory plant) with molecular biological methods (DGGE - Denaturing Gradient Gel Electrophoresis) we were able to elaborate an applicable solution for the rendering plant. Laboratory experiments with a two-stage process layout finally provided complete nitrification overcoming the inhibiting nature of process waters from the rendering plant. DGGE analysis of the second stage activated sludge from the laboratory plant showed a shift in population structure from Nitrosospira sp. towards Nitrosomonas spp. simultaneous to the increase of nitrification capacity. Nitrification capacities comparable to full-scale municipal wastewater treatment plants could be maintained for more than two months. As the design of wastewater treatment plants for nitrification is linked to the growth characteristics of Nitrosomonas spp., established criteria can be applied for the redesign of the full-scale plant.


1992 ◽  
Vol 25 (6) ◽  
pp. 167-183 ◽  
Author(s):  
H. Siegrist ◽  
M. Tschui

The wastewater of the municipal treatment plants Zürich-Werdhölzli (350000 population equivalents), Zürich-Glatt (110000), and Wattwil (20000) have been characterized with regard to the activated sludge model Nr.1 of the IAWPRC task group. Zürich-Glatt and Wattwil are partly nitrifying treatment plants and Zürich-Werdhölzli is fully nitrifying. The mixing characteristics of the aeration tanks at Werdhölzli and Glatt were determined with sodium bromide as a tracer. The experimental data were used to calibrate hydrolysis, heterotrophic growth and nitrification. Problems arising by calibrating hydrolysis of the paniculate material and by measuring oxygen consumption of heterotrophic and nitrifying microorganisms are discussed. For hydrolysis the experimental data indicate first-order kinetics. For nitrification a maximum growth rate of 0.40±0.07 d−1, corresponding to an observed growth rate of 0.26±0.04 d−1 was calculated at 10°C. The half velocity constant found for 12 and 20°C was 2 mg NH4-N/l. The calibrated model was verified with experimental dam of me Zürich-Werdhölzli treatment plant during ammonia shock load.


2018 ◽  
Vol 78 (3) ◽  
pp. 644-654 ◽  
Author(s):  
J. Olsson ◽  
S. Schwede ◽  
E. Nehrenheim ◽  
E. Thorin

Abstract A mix of microalgae and bacteria was cultivated on pre-sedimented municipal wastewater in a continuous operated microalgae-activated sludge process. The excess material from the process was co-digested with primary sludge in mesophilic and thermophilic conditions in semi-continuous mode (5 L digesters). Two reference digesters (5 L digesters) fed with waste-activated sludge (WAS) and primary sludge were operated in parallel. The methane yield was slightly reduced (≈10%) when the microalgal-bacterial substrate was used in place of the WAS in thermophilic conditions, but remained approximately similar in mesophilic conditions. The uptake of heavy metals was higher with the microalgal-bacterial substrate in comparison to the WAS, which resulted in higher levels of heavy metals in the digestates. The addition of microalgal-bacterial substrate enhanced the dewaterability in thermophilic conditions. Finally, excess heat can be recovered in both mesophilic and thermophilic conditions.


1992 ◽  
Vol 26 (3-4) ◽  
pp. 783-790
Author(s):  
J. Pedersen

A newly developed simulation program, based on the Activated Sludge Model No. 1, has been investigated for its controlling abilities. The program is capable of simulating most of the control types which have been applied to wastewater treatment plants. The program was tested on a nitrifying and a denitrifying treatment plant. The results showed that the model makes good simulations of the applied controls.


Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 421
Author(s):  
Dimitra C. Banti ◽  
Michail Tsangas ◽  
Petros Samaras ◽  
Antonis Zorpas

Membrane bioreactor (MBR) systems are connected to several advantages compared to the conventional activated sludge (CAS) units. This work aims to the examination of the life cycle environmental impact of an MBR against a CAS unit when treating municipal wastewater with similar influent loading (BOD = 400 mg/L) and giving similar high-quality effluent (BOD < 5 mg/L). The MBR unit contained a denitrification, an aeration and a membrane tank, whereas the CAS unit included an equalization, a denitrification, a nitrification, a sedimentation, a mixing, a flocculation tank and a drum filter. Several impact categories factors were calculated by implementing the Life Cycle Assessment (LCA) methodology, including acidification potential, eutrophication potential, global warming potential (GWP), ozone depletion potential and photochemical ozone creation potential of the plants throughout their life cycle. Real data from two wastewater treatment plants were used. The research focused on two parameters which constitute the main differences between the two treatment plants: The excess sludge removal life cycle contribution—where GWPMBR = 0.50 kg CO2-eq*FU−1 and GWPCAS = 2.67 kg CO2-eq*FU−1 without sludge removal—and the wastewater treatment plant life cycle contribution—where GWPMBR = 0.002 kg CO2-eq*FU−1 and GWPCAS = 0.14 kg CO2-eq*FU−1 without land area contribution. Finally, in all the examined cases the environmental superiority of the MBR process was found.


2013 ◽  
Vol 807-809 ◽  
pp. 694-698
Author(s):  
Rong Xin Huang ◽  
Zhen Xing Wang ◽  
Gang Liu ◽  
Qi Jin Luo

In order to guarantee the reliability and security of reclaiming water, research on the removal efficiency of the environmental endocrine chemicals (EDCs) --the Phthalate Esters (PAEs) in conventional secondary activated sludge and wastewater reclamation and reuse process was undergoing at Harbin wastewater treatment plant (WWTP). The wastewater samples were colleted from every unit effluent of WWTP. The results showed that contamination of EDCs were presented in municipal wastewater at Harbin and the concentrations of the four PAEs were 21.01μg/L for Di-n-butyl Phthalate (DBP); 9.63μg/L for Di-n-octyl Phthalate (DnOP); 4.56μg/L for Diethyl Phthalate (DEP); 1.96μg/L for Dimethyl Phthalate (DMP) respectively in the influent. The conventional activated sludge has good removal efficiencies performance on DMP, DEP and DBP. With the increasing of molecular weight and branch chains of PAEs contaminations, the removal rate of the four PAEs in the conventional activated sludge process decreased from 99.82%(DMP),90.60%(DEP),90.10%(DBP) to the only 45.13% removal rate for DnOP, which was mostly removed from primary treatment but no from secondary activated sludge process; Coagulation-air flotation plus filtration process was not a feasible way to remove PAEs from reclaiming treatment units.


2013 ◽  
Vol 20 (1) ◽  
pp. 199-208 ◽  
Author(s):  
Marketa Julinova ◽  
Jan Kupec ◽  
Roman Slavik ◽  
Maria Vaskova

Abstract A synthetic polymer, polyvinylpyrrolidone (PVP - E 1201) primarily finds applications in the pharmaceutical and food industries due to its resistance and zero toxicity to organisms. After ingestion, the substance passes through the organism unchanged. Consequently, it enters the systems of municipal wastewater treatment plants (WWTP) without decomposing biologically during the waste treatment process, nor does it attach (through sorption) to particles of activated sludge to any significant extent, therefore, it passes through the system of a WWTP, which may cause the substance to accumulate in the natural environment. For this reason the paper investigates the potential to initiate aerobic biodegradation of PVP in the presence of activated sludge from a municipal wastewater treatment plant. The following agents were selected as the initiators of the biodegradation process - co-substrates: acrylamide, N-acethylphenylalanine and 1-methyl-2-pyrrolidone, a substance with a similar structure to PVP monomer. The biodegradability of PVP in the presence of co-substrates was evaluated on the basis of biological oxygen demand (BOD) as determined via a MicroOxymax O2/CO2/CH4 respirometer. The total substrate concentration in the suspension equaled 400 mg·dm-3, with the ratio between PVP and the cosubstrate being 1:1, while the concentration of the dry activated sludge was 500 mg·dm-3. Even though there was no occurrence of a significant increase in the biodegradation of PVP alone in the presence of a co-substrate, acrylamide appeared to be the most effective type of co-substrate. Nevertheless, a recorded decrease in the slope of biodegradation curves over time may indicate that a process of primary decomposition was underway, which involves the production of metabolites that inhibit activated sludge microorganisms. The resulting products are not identified at this stage of experimentation.


2008 ◽  
Vol 58 (4) ◽  
pp. 953-956 ◽  
Author(s):  
L. Balest ◽  
G. Mascolo ◽  
C. Di Iaconi ◽  
A. Lopez

The removal of selected endocrine disrupter compounds (EDCs), namely estrone(E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), bisphenol A (BPA) and 4-tert-octylphenol (4t-OP) from municipal wastewater was investigated using a sequencing batch biofilter granular reactor (SBBGR), a new system for biological treatment based on aerobic granular biomass. This new biological treatment is characterized by high biomass concentration (up to 40 g/L), high sludge retention times (up to 6 months) and low sludge production (i.e., an order of magnitude lower than commonly reported for conventional biological technologies). The investigation was carried out comparing a demonstration SBBGR system with a conventional full-scale activated sludge process. Results showed that the SBBGR performed better than a conventional activated sludge process in removing E1, E2, BPA and 4t-OP. In fact, the average removal percentages of the above mentioned EDCs, obtained during a four month operating period, were 62.2, 68, 91.8, 77.9% and 56.4, 36.3, 71.3, 64.6% for the demonstrative SBBGR system and the conventional activated sludge process of the municipal sewage treatment plant, respectively


Author(s):  
Yongkui Yang ◽  
Longfei Wang ◽  
Feng Xiang ◽  
Lin Zhao ◽  
Zhi Qiao

Controlling wastewater pollution from centralized industrial zones is important for reducing overall water pollution. Microbial community structure and diversity can adversely affect wastewater treatment plant (WWTP) performance and stability. Therefore, we studied microbial structure, diversity, and metabolic functions in WWTPs that treat industrial or municipal wastewater. Sludge microbial community diversity and richness were the lowest for the industrial WWTPs, indicating that industrial influents inhibited bacterial growth. The sludge of industrial WWTP had low Nitrospira populations, indicating that influent composition affected nitrification and denitrification. The sludge of industrial WWTPs had high metabolic functions associated with xenobiotic and amino acid metabolism. Furthermore, bacterial richness was positively correlated with conventional pollutants (e.g., carbon, nitrogen, and phosphorus), but negatively correlated with total dissolved solids. This study was expected to provide a more comprehensive understanding of activated sludge microbial communities in full-scale industrial and municipal WWTPs.


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