Nitrogen removal upgrade of a wastewater treatment plant within existing reactor volumes: A simulation supported scenario analysis

1996 ◽  
Vol 34 (3-4) ◽  
pp. 339-346 ◽  
Author(s):  
F. Coen ◽  
B. Vanderhaegen ◽  
I. Boonen ◽  
P. A. Vanrolleghem ◽  
L. Van Eyck ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Scenario Analysis ◽  
Biological Process ◽  
Treatment Plant ◽  
Cost Effective ◽  
First Flush ◽  
Effective Solution ◽  
Measuring Campaign ◽  
Anoxic Zones ◽  
The Impact

A simulation supported scenario analysis for the upgrading of a municipal WWTP Hoogstraten (Belgium) with nitrogen removal is presented. The most cost-effective solution is to create optimal aerobic and anoxic conditions within the existing reactor volumes. The IAWQ-model No. 1 was used for the simulation of the biological reactor. A measuring campaign and some specific respirometric tests provided the necessary information for calibration and verification of the biological model. The study consisted of two parts: 1) increase of the denitrification capacity, and 2) optimisation of operation. First, the impact of three measures, i.e. creation of anoxic zones, implementation of step feeding and introduction of internal recirculation, was evaluated by means of simulation. For this purpose a standard time variant influent was defined based on the measuring campaign. This approach made it easy to compare the different scenarios. In the second part of the study some specific problems were handled. To avoid high nitrate concentrations during weekends three possible control actions were simulated. The simulation study also evaluated the usefulness of the primary clarifier in the upgraded design and the effect on the biological process of first flush during intensive rainfall.

scholarly journals Roadworks Warning—Closure of a Lane, the Impact of C-ITS Messages

2020 ◽  
Vol 5 (3) ◽  
pp. 27 ◽  
Author(s):  
Serio Angelo Maria Agriesti ◽  
Luca Studer ◽  
Giovanna Marchionni ◽  
Paolo Gandini ◽  
Xiaobo Qu
Keyword(s):  
Cost Effective ◽  
Intelligent Transport System ◽  
Use Case ◽  
Market Penetration ◽  
Effective Solution ◽  
Delay Reduction ◽  
Intelligent Transport ◽  
Dedicated Short Range Communications ◽  
Traffic Efficiency ◽  
The Impact

By now, it is widely acknowledged among stakeholders and academia that infrastructures will have to be composed both by a physical component and a digital one. The deployment of technologies exploiting dedicated short-range communications is viewed as the most cost-effective solution to face the foreseen growth of mobility. Still, little has been done to define the best implementation logic of DSRC. Aim of this paper is to frame the possible impacts arising by the implementation of a cooperative intelligent transport system (C-ITS)-use case: roadworks warning—closure of a lane, and, in order to achieve this result, microsimulations are exploited. The results are intended to support both road operators and car-makers in defining the best operational logics and the possible benefits achievable by presenting the cooperative message at a certain distance for certain market penetrations. Moreover, if the C-ITS message actually entails benefits or simply disrupts the upstream traffic should be assessed in advance, before implementing the system. The obtained results show that the risk of disruption and of reduction in traffic efficiency arises at lower market penetration levels. Nevertheless, a consistent trend in delay reduction is recorded upstream the roadworks, the highest reduction being equal to 8.66%. Moreover, the average speed at the roadworks entrance on the closing lane increases by a difference equal to around 10 km/h, while the average time in the queue at the highest market penetration reduces by 60 s on the open lane and 25 s on the closing one. These presented results reflect the way the traffic shifts from the slow to the fast lane thanks to the C-ITS system and effectively frames both the potentialities and the risks of the system.

Steam Turbine Design Considerations for Ultrasupercritical Cycles

2010 ◽  
Author(s):  
Justin Zachary
Keyword(s):  
Power Generation ◽  
Cost Effective ◽  
Design Phase ◽  
Steam Turbines ◽  
Effective Solution ◽  
Technical Approach ◽  
Design Considerations ◽  
Balance Of Plant ◽  
Turbine Design ◽  
The Impact

The current coal-fired power generation market requires higher cycle efficiencies not only for economic reasons, but also as a means of reducing plant carbon footprint. To achieve these goals, the plant must operate at higher pressures and temperatures in the supercritical (SC) and ultrasupercritical (USC) domains. This paper describes Bechtel’s experience and challenges in regard to the conceptual design and integration of large steam turbines operating under these severe conditions. Several examples of projects are described wherein Bechtel applied this neutral but proactive technical approach in the development or design phase to achieve the best and most cost-effective solution for its customers. The topics presented also relate to steam cycle optimization in terms of plant output, steam conditions, number of reheat circuits, and type and number of heaters. The impact on balance of plant systems, including water treatment, availability, and redundancy criteria, is also addressed.

Upgrading of the Treatment Plants in Stockholm to Meet More Stringent Requirements

1990 ◽  
Vol 22 (7-8) ◽  
pp. 77-84
Author(s):  
J. Hultgren ◽  
L.-G. Reinius ◽  
M. Tendaj
Keyword(s):  
Nitrogen Removal ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Design Flow ◽  
Limit Values ◽  
Mean Values ◽  
Reject Water ◽  
Low Phosphorus ◽  
Anoxic Zones

The purification requirements for the Stockholm sewage treatment plants will become more stringent in the future. The expected limit values for the effluent, expressed as annual mean values, are for BOD7, Tot-P, and Tot-N, 10, 0.3 and 15 mg/l respectively. If these contents are multiplied by the design flow values for the three plants, we obtain the maximum quantities which may be released. If the relevant authorities permit the municipality to distribute these total quantities as desired between the three plants, future necessary extensions can be optimized. The following main principles apply to an extension of the three plants: Loudden sewage treatment plant: This comparatively small treatment plant could, if the requirements are lower than in the other two plants, continue in operation with no other extensions than the inclusion of anoxic zones. It would, however, be necessary to refurbish the plant after a number of years of neglected maintenance. Bromma sewage treatment plant: The biological stage was extended during the 1982-84 period. For this reason, the municipality suggests that no further extensions of the aeration tanks be required, before 1995 at the earliest. A nitrogen removal with outgoing contents of Tot-N of 15-17 mg/l is expected to be achieved by measures taken to reduce the load on the biological stage instead. These measures consist of centrifuging the excess sludge and pumping it directly to the digesters instead of returning it to the inlet. Furthermore, separate treatment of the reject water from the sludge centrifuges is planned. A third measure could be changing over to a more efficient precipitation chemical to permit a further reduction of the load on the biological stage with regard to, inter alia, BOD7, Tot-N etc. To meet the requirements for phosphorus removal (0.3 mg/l), the plant will be extended with a filter stage after the existing biological stage. Henriksdal sewage treatment plant: At this plant, which is the largest of the three, the largest extensions are planned. To meet the requirements for nitrogen removal, the present volumes in the aeration tanks will be tripled and will be utilized as anoxic and aerated zones as required. Three new lines with aeration tanks and secondary sedimentation tanks will be constructed. The existing aeration tanks will also be deepened from 5 to 12 m. The requirements for low phosphorus contents in the effluent will be met by installing a filter stage, as in the Bromma plant.

Cost-effective solutions for water quality improvement in the Dommel River supported by sewer–WWTP–river integrated modelling

2013 ◽  
Vol 68 (5) ◽  
pp. 965-973 ◽  
Author(s):  
Lorenzo Benedetti ◽  
Jeroen Langeveld ◽  
Arjen F. van Nieuwenhuijzen ◽  
Jarno de Jonge ◽  
Jeroen de Klein ◽  
...  
Keyword(s):  
Control Strategies ◽  
Treatment Plant ◽  
Water System ◽  
Cost Effective ◽  
Integrated Modelling ◽  
Model Parameters ◽  
Urban Wastewater ◽  
Real Time Control ◽  
Worst Case ◽  
The Impact

This project aims at finding cost-efficient sets of measures to meet the Water Framework Directive (WFD) derived goals for the Dommel River (The Netherlands). Within the project, both acute and long-term impacts of the urban wastewater system on the chemical and ecological quality of the river are studied with a monitoring campaign in the urban wastewater system (wastewater treatment plant and sewers) and in the receiving surface water system. An integrated model, which proved to be a powerful tool to analyse the interactions within the integrated urban wastewater system, was first used to evaluate measures in the urban wastewater system using the existing infrastructure and new real-time control strategies. As the latter resulted to be beneficial but not sufficient, this paper investigated the use of additional infrastructural measures to improve the system cost-effectively and have it meet the Directive's goals. Finally, an uncertainty analysis was conducted to investigate the impact of uncertainty in the main model assumptions and model parameters on the performance robustness of the selected set of measures. Apart from some extreme worst-case scenarios, the proposed set of measures turned out to be sufficiently robust. Due to the substantial savings obtained with the results of this project, the pay-back time of the whole monitoring and modelling work proved to be less than 5 months. This illustrates the power of mathematical modelling for decision support in the context of complex urban water systems.

Full-Scale Application of Nitrogen Removal with Methanol as Carbon Source

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1077-1086 ◽  
Author(s):  
U. Nyberg ◽  
H. Aspegren ◽  
B. Andersson ◽  
J. la C. Jansen ◽  
I.S. Villadsen
Keyword(s):  
Carbon Source ◽  
Nitrogen Removal ◽  
Nitrate Removal ◽  
Sewage Treatment ◽  
Carbon Sources ◽  
Treatment Plant ◽  
Cost Effective ◽  
High Level ◽  
Plant Configuration ◽  
Composite Samples

In Sweden many advanced sewage treatment plants for BOD and phosphorus removal have to be extended with nitrogen removal. Due to existing plant configuration and wastewater composition, denitrification with supply of an external carbon source can be a cost-effective solution in many cases. At the Klagshamn wastewater treatment plant in Malmo investigations for extensive nitrogen removal have been made in a single-sludge system with pre-precipitation and post-denitrification where methanol was added for denitrification. Results from the tests showed that a high level of nitrogen removal can be reached, and that the process was stable and easy to operate. The process application gave less supplementary cost for an extended nitrogen removal than for upgrading the plant with larger basin volumes. In order to examine the purification performance caused by the addition of methanol, the starting period was followed extensively with online nitrate sensors and daily composite samples. The development of the denitrif ication capacity of the sludge with methanol and acetate as carbon sources was followed and microbiological changes were examined microscopically. Complete denitrification was obtained after approximately one month at 10°C. The denitrification capacity of the sludge with methanol reached that of acetate after about the same time. The microscopic examination revealed a growing population of budding and/or appendaged bacteria, presumably Hyphomicrobium spp, reaching a stable maximum at the time when optimal nitrate removal occurred.

scholarly journals Evaluation of the biogas potential of a lignocellulosic residue

2021 ◽  
Author(s):  
Nardjes Guendouz ◽  
Hynda Rezzaz-Yazid ◽  
Salima Laib ◽  
Zahra Sadaoui
Keyword(s):  
Wastewater Treatment ◽  
Biological Process ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Cattle Manure ◽  
Toxic Substances ◽  
Lignocellulosic Materials ◽  
Ammoniacal Nitrogen ◽  
Lignocellulosic Residue ◽  
The Impact

Abstract Anaerobic digestion (AD) or methanization is a biological process that allows the treatment of organic wastes and the production of renewable energy as biogas. This research describes assessment and optimization of dates pedicels rich in organic components under the conditions of mesophiles in co-digestion in association with the cattle manure and sludge of the wastewater treatment plant (WWTP). To realize this objectives, we investigated the impact of substrate load (date pedicel) on the co-digestion anaerobic of date pedicels and the sludge in wastewater treatment plants. The different parameters of the digester stability such as the pH, VFA, CAT, ammoniacal nitrogen, and the volume of biogas produced were followed. The results show that by increasing the mass of the pedicels and therefore the percentage of the substrate in the reactor, from 0.5 to 1% (W/V), the volume of produced biogas increases by five times. However, an increase in the percentage of the substrate introduced into the digester from 1 to 2% resulted in a slight decrease in the volume of biogas produced. The use of fresh cattle manure as inoculum shown a significant improvement (40%) in the production of biogas, which can be attributed to the nature of the inoculum. Indeed, cattle manure fresh is more adapted for the fermentation of lignocellulosic materials unlike sludge of wastewater treatment plants which may contain toxic substances that limit their use in AD.

An alternate oxic-anoxic process automatically controlled. Theory and practice in a real treatment plant network

2004 ◽  
Vol 48 (11-12) ◽  
pp. 337-344 ◽  
Author(s):  
P. Battistoni ◽  
R. Boccadoro ◽  
D. Bolzonella ◽  
M. Marinelli
Keyword(s):  
Flow Rate ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Control Device ◽  
Theory And Practice ◽  
Process Efficiency ◽  
Plant Management ◽  
Operational Parameters ◽  
The Impact

A simple mathematical model of an alternate oxic-anoxic process has been elaborated. It enables us to optimise the cycle time on the basis of maximum nitrates concentration in the effluent and the desired nitrogen removal performance. At the same time the model can be employed to verify the impact of the variations of flow rate and influent characteristics as well as the operational parameters of the process. Actually, the model confirms the process efficiency but its feasibility in real plants needs a local or remote process control. To verify these theoretical conclusions a real wastewater plant (700 PE) has been upgraded in an alternate oxic-anoxic process. It was implemented with software able to elaborate the data of dissolved oxygen concentration and oxidation reduction potential. Moreover, the evaluation of the flexing points was performed to manage mixer and blowers. A one-year experience of plant management allowed us to obtain very high nitrogen removal. However, the performances were different during wet or dry weather periods. The statistical analysis of probe signals evaluation confirmed the capability of the control device to detect the flexing points during the anoxic phase (70-94%). On the other hand, the capability of detecting the DO signal was lower, in particular when the oxygen demand was similar to the amount of supplied oxygen. The hourly variations of flow rate and mass loading determines different conditions for starting the anoxic phase: over aeration, over loading and the equivalence of oxygen demand and supply, are the main factors determining the blowers stopping.

scholarly journals Juvenile Justice Realignment: A policy analysis of California Senate Bill 823

2021 ◽  
Author(s):  
◽  
Stewart Patri
Keyword(s):  
Juvenile Justice ◽  
Policy Analysis ◽  
Juvenile Offender ◽  
Cost Effective ◽  
Effective Solution ◽  
Population Type ◽  
Senate Bill ◽  
Age Range ◽  
The Impact ◽  
County Agencies

New legislation (Senate Bill 823) in the State of California, to realign the serious felony juvenile offender population from state facilities to county facilities, will go into effect July 1, 2021 (SB823, 2020). County probation departments will now be faced with determining how to provide adequate programming to a new population type of serious offender that includes adults in the age range of 18 to 25 years old. This places pressure on smaller county agencies to either find a cost-effective solution to modify their current facilities and programs or send this population to other county agencies. This research project analyzes the impact of SB823 on a sample of smaller counties.

scholarly journals Assessment and Containment of Aflatoxin Impact on the Health by Solar Drying

2020 ◽  
Vol 15 (3) ◽  
pp. 141-145
Author(s):  
Smriti Gupta ◽  
Shishir Kumar Verma ◽  
Sanjay Kumar
Keyword(s):  
Aspergillus Flavus ◽  
Crude Extract ◽  
Positive Impact ◽  
Health Hazard ◽  
Cost Effective ◽  
Solar Drying ◽  
Effective Solution ◽  
Contaminated Food ◽  
Natural Contamination ◽  
The Impact

Solar drying is well known to human being since time immemorial. Its impact on our life is multidimensional. However, gradual changes in our life style have consistently reduced its positive impact during last century. It is more evident in towns. One of them is contamination of dietary items by fungi, which produces carcinogens. The ubiquitous fungus Aspergillus flavus is notorious for contaminating many important crops and food stuffs with the carcinogenic mytoxin, aflatoxin. The Aspergillus spp., are widely spread in nature and contaminated food supplies of humans and animals resulting in health hazards and even death. A detail survey of wholesale depots was made to assess the impact of aflatoxin on the health of the human and other animals by the natural contamination of the dietary items. Samples of different dietary items collected from different wholesale depots belonging to five different mohallas of Darbhanga town (Bihar, India) during 2012 were brought to the laboratory for further studies. The findings suggest that Aspergillus flavus appeared as the most dominant mycoflora in general. Present bioassay on Daphnia magna subjected to static exposure of different concentration of A. flavus crude extract clearly indicate the stain to be potential toxic producer. The rate of mortality increased with increased in amount of toxin. Solar drying is a cost-effective solution to overcome this serious problem. The technology is well developed and tested. In this paper, appropriate solar dryer design is further proposed for households to eliminate this serious health hazard.

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