Thermophilic anaerobic digestion and pasteurisation. Practical experience from Danish wastewater treatment plants

2000 ◽  
Vol 42 (9) ◽  
pp. 65-72 ◽  
Author(s):  
B. Nielsen ◽  
G. Petersen

Increasing sludge disposal costs have highly intensified the interest in reducing the sludge quantities from Danish wastewater treatment plants. By upgrading existing mesophilic digesters to the thermophilic temperature range, the retention time can be halved and many digesters designed only for primary sludge will have sufficient capacity to treat also the biological excess sludge. At the moment, eight full-scale thermophilic digesters are in operation in Denmark and five are under construction. This paper describes the full-scale experience gained from digestion of biological excess sludge as well as a mixture of primary and biological sludge. Thermophilic digestion has proven to be a good and stable process for solids reduction and pathogen removal. The digested sludge can be dewatered to a high solids content and thereby the sludge quantity for disposal can be reduced by 30-40% depending on the type of wastewater treatment plant. A drawback of the process is that the polymer costs for sludge dewatering may be increased depending on the sludge type.

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 650 ◽  
Author(s):  
Ioanna Zerva ◽  
Ioanna Alexandropoulou ◽  
Maria Panopoulou ◽  
Paraschos Melidis ◽  
Spyridon Ntougias

Wastewater treatment plants (WWTPs) highly contribute to the transmission of antibiotic resistance genes (ARGs) in the environment. In this work, the diversity of ermF, ermB, sul1 and int1-enconding genes was examined in the influent, the mixed liquor and the effluent of a full-scale WWTP. Based on the clones analyzed, similar genotypes were recorded at all process stages. However, distinct genotypes of int1 were responsible for the expression of sul1 and ermF genes in Gammaproteobacteria and Bacteroidetes, respectively. Due to the detection of similar ARGs profiles throughout the biological process, it is concluded that additional treatment is needed for their retention.


2006 ◽  
Vol 54 (5) ◽  
pp. 51-58 ◽  
Author(s):  
T. Yamaguchi ◽  
Y. Yao ◽  
Y. Kihara

A novel sludge disintegration system (JFE-SD system) was developed for the reduction of excess sludge production in wastewater treatment plants. Chemical and biological treatments were applied to disintegrate excess sludge. At the first step, to enhance biological disintegration, the sludge was pretreated with alkali. At the second step, the sludge was disintegrated by biological treatment. Many kinds of sludge degrading microorganisms integrated the sludge. The efficiency of the new sludge disintegration system was confirmed in a full-scale experiment. The JFE-SD system reduced excess sludge production by approximately 50% during the experimental period. The quality of effluent was kept at quite a good level. Economic analysis revealed that this system could significantly decrease the excess sludge treatment cost.


2015 ◽  
Vol 71 (4) ◽  
pp. 487-494 ◽  
Author(s):  
A. Marchi ◽  
S. Geerts ◽  
M. Weemaes ◽  
S. Wim ◽  
V. Christine

To date, phosphorus recovery as struvite in wastewater treatment plants has been mainly implemented on water phases resulting from dewatering processes of the sludge line. However, it is possible to recover struvite directly from sludge phases. Besides minimising the return loads of phosphorus from the sludge line to the water line, placing such a process within the sludge line is claimed to offer advantages such as a higher recovery potential, enhanced dewaterability of the treated sludge, and reduced speed of scaling in pipes and dewatering devices. In the wastewater treatment plant at Leuven (Belgium), a full-scale struvite recovery process from digested sludge has been tested for 1 year. Several monitoring campaigns and experiments provided indications of the efficiency of the process for recovery. The load of phosphorus from the sludge line returning to the water line as centrate accounted for 15% of the P-load of the plant in the reference situation. Data indicated that the process divides this phosphorus load by two. An improved dewaterability of 1.5% of dry solids content was achieved, provided a proper tuning of the installation. Quality analyses showed that the formed struvite was quite pure.


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.


2005 ◽  
Vol 52 (4) ◽  
pp. 63-70 ◽  
Author(s):  
D.H.J.G. Berends ◽  
S. Salem ◽  
H.F. van der Roest ◽  
M.C.M. van Loosdrecht

Over the past years there has been a growing interest for compact, simple, low cost and robust technologies to upgrade wastewater treatment plants for nitrogen removal. The BABE (Bio Augmentation Batch Enhanced) technology is such a new concept. This patented system for biological treatment of sludge liquor – the effluent produced from digested sludge – uses a new principle, boosting the nitrifying bacteria in a side stream in such a way that the activated sludge in the main process is augmented. This augmentation increases the nitrification capacity of the wastewater treatment plant (wwtp). Experiments on a practical scale have demonstrated the effective and stable operation of the BABE technology. Model studies supported by the results of the full-scale tests showed that the technology can be applied in several situations, i.e. 1) introducing nitrification at high loaded wwtps; 2) enhancing nitrification at wwtps with incomplete nitrification; 3) enlarging denitrification at wwtps with complete nitrification. Most likely this year a full-scale application will be realized in the Netherlands at a wwtp with insufficient nitrification throughout the year.


2015 ◽  
Vol 72 (3) ◽  
pp. 364-370 ◽  
Author(s):  
Agostina Chiavola ◽  
Alessandra Ridolfi ◽  
Emilio D'Amato ◽  
Simona Bongirolami ◽  
Ennio Cima ◽  
...  

Sludge reduction in a wastewater treatment plant (WWTP) has recently become a key issue for the managing companies, due to the increasing constraints on the disposal alternatives. Therefore, all the solutions proposed with the aim of minimizing sludge production are receiving increasing attention and are tested either at laboratory or full-scale to evaluate their real effectiveness. In the present paper, electro-kinetic disintegration has been applied at full-scale in the recycle loop of the sludge drawn from the secondary settlement tank of a small WWTP for domestic sewage. After the disintegration stage, the treated sludge was returned to the biological reactor. Three different percentages (50, 75 and 100%) of the return sludge flow rate were subjected to disintegration and the effects on the sludge production and the WWTP operation efficiency evaluated. The long-term observations showed that the electro-kinetic disintegration was able to drastically reduce the amount of biological sludge produced by the plant, without affecting its treatment efficiency. The highest reduction was achieved when 100% return sludge flow rate was subjected to the disintegration process. The reduced sludge production gave rise to a considerable net cost saving for the company which manages the plant.


2016 ◽  
Vol 11 (2) ◽  
pp. 459-468 ◽  
Author(s):  
P. Kängsepp ◽  
J. Väänänen ◽  
K. Örning ◽  
M. Sjölin ◽  
P. Olsson ◽  
...  

Microscreening (using Discfilters) is a widely used technology for suspended solids removal in tertiary effluent streams of wastewater treatment plants. Several pilot studies have shown the feasibility of using coagulation and flocculation in combination with microscreens for advanced phosphorus removal, but the number of full-scale references is still limited. In summer 2014, the first Scandinavian full-scale Discfilter installation with 2-stage chemical pre-treatment (coagulation and flocculation) was started up at the Arvidstorp wastewater treatment plant in Trollhättan (Sweden). The results obtained during the first year of operation proved that low suspended solids and total phosphorus effluent values could be achieved (<5 and <0.2 mg/l, respectively). These results were obtained even during heavy rainfall, when biologically and primary treated water were mixed at the influent of the Discfilter installation, before the coagulation and flocculation tanks. Further analysis of the results showed that Discfilter in combination with coagulant and polymer pre-treatment is a robust and reliable technology with low energy demand (34 Wh/m3) and a high recovery (1.9 ± 0.4% of influent flow discharged as reject).


PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255836
Author(s):  
Shuyuan Deng ◽  
Bo Wang ◽  
Wenda Zhang ◽  
Sanbao Su ◽  
Hao Dong ◽  
...  

Oil-produced wastewater treatment plants, especially those involving biological treatment processes, harbor rich and diverse microbes. However, knowledge of microbial ecology and microbial interactions determining the efficiency of plants for oil-produced wastewater is limited. Here, we performed 16S rDNA amplicon sequencing to elucidate the microbial composition and potential microbial functions in a full-scale well-worked offshore oil-produced wastewater treatment plant. Results showed that microbes that inhabited the plant were diverse and originated from oil and marine associated environments. The upstream physical and chemical treatments resulted in low microbial diversity. Organic pollutants were digested in the anaerobic baffled reactor (ABR) dominantly through fermentation combined with sulfur compounds respiration. Three aerobic parallel reactors (APRs) harbored different microbial groups that performed similar potential functions, such as hydrocarbon degradation, acidogenesis, photosynthetic assimilation, and nitrogen removal. Microbial characteristics were important to the performance of oil-produced wastewater treatment plants with biological processes.


2011 ◽  
Vol 63 (12) ◽  
pp. 2838-2845 ◽  
Author(s):  
D. J. I. Gustavsson ◽  
J. la Cour Jansen

Biological treatment in wastewater treatment plants (WWTPs) is a source of nitrogen oxides (N2O, NO and NO2) emitted to the atmosphere. Aerobic ammonia-oxidising bacteria (AOB) have been suggested to be the main source of these emissions. In a full-scale sludge liquor treatment plant at Sjölunda WWTP, it was shown that significant emissions of N2O, NO and NO2 do occur. The plant is operated with nitritation alone, which gives an environment enriched in aerobic AOB. During normal operation, emissions of N2O, NO and NO2 were found to be 3.8%, 0.06% and 0.01% of the ammonium nitrogen load. The N2O emissions were larger than the recommended estimated figure of the Intergovernmental Panel on Climate Change (IPCC) for a complete wastewater treatment plant. The N2O emissions correlated positively with the length of the previous anoxic period, i.e., settling and decantation, and with the ammonium oxidation rate. The NO and NO2 emission profiles were similar and dependent on ammonium oxidation and DO level, but the NO2 concentrations were always lower.


2008 ◽  
Vol 58 (8) ◽  
pp. 1547-1553 ◽  
Author(s):  
P. Phothilangka ◽  
M. A. Schoen ◽  
B. Wett

This paper presents benefits and potential drawbacks of thermal pre-hydrolysis of sewage sludge from an operator's prospective. The innovative continuous Thermo-Pressure-Hydrolysis Process (TDH) has been tested in full-scale at Zirl wastewater treatment plant (WWTP), Austria, and its influence on sludge digestion and dewatering has been evaluated. A mathematical plant-wide model with application of the IWA Activated Sludge Model No.1 (ASM1) and the Anaerobic Digestion Model No.1 (ADM1) has been used for a systematic comparison of both scenarios—operational plant performance with and without thermal pre-hydrolysis. The impacts of TDH pre-hydrolysis on biogas potential, dewatering performance and return load in terms of ammonia and inert organic compounds (Si) have been simulated by the calibrated model and are displayed by Sankey mass flow figures. Implementation of full scale TDH process provided higher anaerobic degradation efficiency with subsequent increased biogas production (+75–80%) from waste activated sludge (WAS). Both effects—enhanced degradation of organic matter and improved cake's solids content from 25.2 to 32.7% TSS—promise a reduction in sludge disposal costs of about 25%. However, increased ammonia release and generation of soluble inerts Si was observed when TDH process was introduced.


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