Benefits and drawbacks of thermal pre-hydrolysis for operational performance of wastewater treatment plants

2008 ◽  
Vol 58 (8) ◽  
pp. 1547-1553 ◽  
Author(s):  
P. Phothilangka ◽  
M. A. Schoen ◽  
B. Wett
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Treatment Plant ◽  
Full Scale ◽  
Plant Performance ◽  
Ammonia Release ◽  
Hydrolysis Process ◽  
Solids Content

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.

Model-based evaluation of nitrogen removal in a tannery wastewater treatment plant

2004 ◽  
Vol 50 (6) ◽  
pp. 251-260 ◽  
Author(s):  
M.S. Moussa ◽  
A.R. Rojas ◽  
C.M. Hooijmans ◽  
H.J. Gijzen ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Computer Modelling ◽  
Treatment Plant ◽  
Domestic Wastewater ◽  
Plant Performance ◽  
Accurate Estimation ◽  
Model Parameters ◽  
Biological Tests

Computer modelling has been used in the last 15 years as a powerful tool for understanding the behaviour of activated sludge wastewater treatment systems. However, computer models are mainly applied for domestic wastewater treatment plants (WWTPs). Application of these types of models to industrial wastewater treatment plants requires a different model structure and an accurate estimation of the kinetics and stoichiometry of the model parameters, which may be different from the ones used for domestic wastewater. Most of these parameters are strongly dependent on the wastewater composition. In this study a modified version of the activated sludge model No. 1 (ASM 1) was used to describe a tannery WWTP. Several biological tests and complementary physical-chemical analyses were performed to characterise the wastewater and sludge composition in the context of activated sludge modelling. The proposed model was calibrated under steady-state conditions and validated under dynamic flow conditions. The model was successfully used to obtain insight into the existing plant performance, possible extension and options for process optimisation. The model illustrated the potential capacity of the plant to achieve full denitrification and to handle a higher hydraulic load. Moreover, the use of a mathematical model as an effective tool in decision making was demonstrated.

Full-scale phosphorus recovery from digested waste water sludge in Belgium – part I: technical achievements and challenges

2015 ◽  
Vol 71 (4) ◽  
pp. 487-494 ◽  
Author(s):  
A. Marchi ◽  
S. Geerts ◽  
M. Weemaes ◽  
S. Wim ◽  
V. Christine
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Recovery Process ◽  
Full Scale ◽  
Phosphorus Recovery ◽  
Water Line ◽  
Recovery Potential ◽  
Reference Situation ◽  
Solids Content

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.

Molecular biological methods (DGGE) as a tool to investigate nitrification inhibition in wastewater treatment

2003 ◽  
Vol 47 (11) ◽  
pp. 165-172 ◽  
Author(s):  
N. Kreuzinger ◽  
A. Farnleitner ◽  
G. Wandl ◽  
R. Hornek ◽  
R. Mach
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Full Scale ◽  
Two Stage ◽  
Plant Laboratory ◽  
Biological Methods

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.

Bulking control by low-dose ozonation of returned activated sludge in a full-scale wastewater treatment plant

2012 ◽  
Vol 65 (9) ◽  
pp. 1654-1659 ◽  
Author(s):  
S. Lyko ◽  
B. Teichgräber ◽  
A. Kraft
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Low Dose ◽  
Wastewater Treatment Plants ◽  
State Of The Art ◽  
Treatment Plant ◽  
Full Scale ◽  
Specific Measure ◽  
Positive Effect

Sludge bulking is still a problem in the operation of state-of-the-art wastewater treatment plants (WWTPs). The ozonation of returned activated sludge (RAS) is an innovative option as a non-specific measure for the control of filament growth. The applicability of sludge ozonation for bulking control of a large wastewater treatment plant was investigated. At a full-scale WWTP one lane was equipped with a sludge ozonation plant for RAS. The implemented sludge ozonation of RAS was tested against the two identical references lanes of the same WWTP. The positive effect on settleability could be clearly proven. Low-dose sludge ozonation could be a technical alternative in comparison with the established chemical measures for bulking control.

Evaluating the treatment performance of a full scale Activated Sludge Plant in Islamabad, Pakistan

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
S. S. Fatima ◽  
S. Jamal Khan
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Full Scale ◽  
Operational Parameter ◽  
Mixed Liquor ◽  
Treatment Performance

In this study, the performance of wastewater treatment plant located at sector I-9 Islamabad, Pakistan, was evaluated. This full scale domestic wastewater treatment plant is based on conventional activated sludge process. The parameters which were monitored regularly included total suspended solids (TSS), mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), biological oxygen demand (BOD), and chemical oxygen demand (COD). It was found that the biological degradation efficiency of the plant was below the desired levels in terms of COD and BOD. Also the plant operators were not maintaining consistent sludge retention time (SRT). Abrupt discharge of MLSS through the Surplus Activated sludge (SAS) pump was the main reason for the low MLSS in the aeration tank and consequently low treatment performance. In this study the SRT was optimized based on desired MLSS concentration between 3,000–3,500 mg/L and required performance in terms of BOD, COD and TSS. This study revealed that SRT is a very important operational parameter and its knowledge and correct implementation by the plant operators should be mandatory.

Enhancing nitrogen removal efficiency in a dyestuff wastewater treatment plant with the IFFAS process: the pilot-scale and full-scale studies

2017 ◽  
Vol 77 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Yanjun Mao ◽  
Xie Quan ◽  
Huimin Zhao ◽  
Yaobin Zhang ◽  
Shuo Chen ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Full Scale ◽  
Nitrification And Denitrification ◽  
Dyestuff Wastewater

Abstract The activated sludge (AS) process is widely applied in dyestuff wastewater treatment plants (WWTPs); however, the nitrogen removal efficiency is relatively low and the effluent does not meet the indirect discharge standards before being discharged into the industrial park's WWTP. Hence it is necessary to upgrade the WWTP with more advanced technologies. Moving bed biofilm processes with suspended carriers in an aerobic tank are promising methods due to enhanced nitrification and denitrification. Herein, a pilot-scale integrated free-floating biofilm and activated sludge (IFFAS) process was employed to investigate the feasibility of enhancing nitrogen removal efficiency at different hydraulic retention times (HRTs). The results showed that the effluent chemical oxygen demand (COD), ammonium nitrate (NH4+-N) and total nitrogen (TN) concentrations of the IFFAS process were significantly lower than those of the AS process, and could meet the indirect discharge standards. PCR-DGGE and FISH results indicated that more nitrifiers and denitrifiers co-existed in the IFFAS system, promoting simultaneous nitrification and denitrification. Based on the pilot results, the IFFAS process was used to upgrade the full-scale AS process, and the effluent COD, NH4+-N and TN of the IFFAS process were 91–291 mg/L, 10.6–28.7 mg/L and 18.9–48.6 mg/L, stably meeting the indirect discharge standards and demonstrating the advantages of IFFAS in dyestuff wastewater treatment.

scholarly journals Biological Nutrient Removal Model No. 2 (BNRM2): a general model for wastewater treatment plants

2013 ◽  
Vol 67 (7) ◽  
pp. 1481-1489 ◽  
Author(s):  
R. Barat ◽  
J. Serralta ◽  
M. V. Ruano ◽  
E. Jiménez ◽  
J. Ribes ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Plant Performance ◽  
Biological Nutrient Removal ◽  
Nitrite Oxidizing Bacteria ◽  
Removal Model

This paper presents the plant-wide model Biological Nutrient Removal Model No. 2 (BNRM2). Since nitrite was not considered in the BNRM1, and this previous model also failed to accurately simulate the anaerobic digestion because precipitation processes were not considered, an extension of BNRM1 has been developed. This extension comprises all the components and processes required to simulate nitrogen removal via nitrite and the formation of the solids most likely to precipitate in anaerobic digesters. The solids considered in BNRM2 are: struvite, amorphous calcium phosphate, hidroxyapatite, newberite, vivianite, strengite, variscite, and calcium carbonate. With regard to nitrogen removal via nitrite, apart from nitrite oxidizing bacteria two groups of ammonium oxidizing organisms (AOO) have been considered since different sets of kinetic parameters have been reported for the AOO present in activated sludge systems and SHARON (Single reactor system for High activity Ammonium Removal Over Nitrite) reactors. Due to the new processes considered, BNRM2 allows an accurate prediction of wastewater treatment plant performance in wider environmental and operating conditions.

An investigation into studying of the activated sludge foaming potential by using physicochemical parameters

2002 ◽  
Vol 46 (1-2) ◽  
pp. 525-528 ◽  
Author(s):  
K. Hladikova ◽  
I. Ruzickova ◽  
P. Klucova ◽  
J. Wanner
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Physicochemical Parameters ◽  
Wastewater Treatment Plants ◽  
Physicochemical Characteristics ◽  
Full Scale ◽  
Aeration Tank ◽  
Foam Formation ◽  
Individual Parameter

This paper examines how the physicochemical characteristics of the solids are related to foam formation and describes how the foaming potential of full-scale plants can be assessed. The relations among activated sludge and biological foam hydrophobicity, scum index, aeration tank cover and filamentous population are evaluated. Individual parameter comparison reveals the scumming intensity can be estimated only on the assumption that foams is already established. None of the above mentioned characteristics can be reliably used to predict the foaming episodes at wastewater treatment plants.

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