Fat, oil and grease - Sewer contamination prevention strategies and double-dosage concept for fat traps and pressure mains

2011 ◽  
Vol 6 (2) ◽  
Author(s):  
Wolfram Franke ◽  
Marina Ettl ◽  
Daniel Roldan ◽  
Guido Kuhn ◽  
Anne Mette Langholm ◽  
...  
Keyword(s):  
Hydrogen Sulphide ◽  
Additional Treatment ◽  
Full Scale ◽  
Prevention Strategies ◽  
Oil And Grease ◽  
Sewer Systems ◽  
Sewer Network ◽  
Pumping Stations ◽  
Full Scale Tests

Disposal of fat, oil and grease (FOG) in sewer systems cause blockages, fatal errors of pumping stations, increased maintenance, odours, hydrogen sulphide (H2S) emissions and corrosion. Hence, solutions to prevent FOG disposals are desirable. Challenges are prevention of FOG contamination of sewer systems and removal of FOG disposals. A survey and lab as well as full scale tests were performed. In the first place fat traps and grease inceptors should be installed to prevent FOG contamination what is documented as being very effective. A case study shows that the operation of fat traps may indeed produce further problems, especially H2S emissions, what demands an additional treatment. Removal of FOG disposals can be handled by applying enzymes to the affected sewer network. It was found that enzymes are preferable towards surfactants to remove FOG disposals. It appears to be a solution to have one dosing site that is equipped with separately controlled dosing pumps for conditioners for H2S removal as well as FOG removal.

Network based controller systems for pre-conditioning of waste water in sewer systems

2012 ◽  
Vol 7 (2) ◽  
Author(s):  
Wolfram Franke ◽  
Marina Ettl ◽  
Tim Corben ◽  
Guido Kuhn
Keyword(s):  
Communication Technology ◽  
Preventive Treatment ◽  
Oil And Grease ◽  
Sewer Systems ◽  
Communications Network ◽  
Sewer Network ◽  
Local Solutions ◽  
Odour Emissions ◽  
Technical Solutions

Sewer network odour emissions have become a focus due to environmental regulations and, in the case Hydrogen Sulphide (H2S) induced corrosion, due to safety and sustainability. For these reasons the establishment of emission treatment is recommended. Sewer emission treatment focuses on local solutions rather than sewer-wide network treatment. The dosing of chemicals for this purpose is usually done section-wise. Obviously there is optimization potential when sewers are understood and treated as networks. Preventive treatment can be optimized by information from downstream and curative treatment by information from upstream. Such concepts demand communication technology and monitoring of several parameters at various locations in the sewer network. In the presented case study a digital communications network is used to control H2S emissions and fat, oil and grease (FOG) disposal in a sewer network. Moreover it was shown that technical solutions are available to use sewers as controlled reactors rather than just let them be a source of problems. An overview of today's standard dosing systems and strategies for odour and corrosion control is also given.

A Case Study of Dynamic Instability in a Planing Hull

1987 ◽  
Vol 24 (02) ◽  
pp. 143-163
Author(s):  
Louis Codega ◽  
James Lewis
Keyword(s):  
High Speed ◽  
Dynamic Instability ◽  
Test Procedure ◽  
Large Angle ◽  
Model Tests ◽  
Full Scale ◽  
Planing Craft ◽  
Normal Operating ◽  
Full Scale Tests

Soon after introduction into service, a class of high-speed planing boats began to exhibit a dynamic instability that manifested itself in the craft trimming by the bow, rolling to a large angle of heel to port, and broaching violently to starboard, all within five seconds. This behavior, which occurred within the craft's normal operating envelope, could not be attributed to operator causes and resulted in unacceptable operating restrictions being placed on the craft. After a number of unsuccessful attempts to remedy the problem, an investigation to research possible causes was undertaken. Concurrently, a test boat was instrumented to quantify its behavior and, most importantly, to record the hydrodynamic bottom pressures acting while this phenomenon occurs. The craft is described and initial attempts at solving the problem are outlined. The results of research on this type of phenomena in both planing craft and flying boats are presented. The instrumentation system, complex for this size craft, is detailed and the test procedure described. The results of the full-scale tests are given, along with qualitative comparisons with other craft that display a similar problem and model tests that would indicate the possibility of such instabilities. The cause of the instability is described and recommendations are made to avoid similar problems in future craft.

scholarly journals Groundwater Contribution to Sewer Network Baseflow in an Urban Catchment-Case Study of Pin Sec Catchment, Nantes, France

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 689
Author(s):  
Fabrice Rodriguez ◽  
Amélie-Laure Le Delliou ◽  
Hervé Andrieu ◽  
Jorge Gironás
Keyword(s):  
Urban Areas ◽  
Soil Parameters ◽  
Catchment Scale ◽  
Urban Catchment ◽  
Groundwater Levels ◽  
Sewer Systems ◽  
Sewer Network ◽  
Urban Catchments ◽  
Groundwater Contribution

Sewer systems affect urban soil characteristics and subsoil water flow. The direct connection observed between baseflow in sewer systems under drainage infiltrations and piezometric levels influences the hydrological behavior of urban catchments, and must consequently be considered in the hydrologic modeling of urban areas. This research studies the groundwater contribution to sewer networks by first characterizing the phenomenon using experimental data recorded on a small urban catchment in Nantes (France). Then, the model MODFLOW was used to simulate the infiltration of groundwater into a sewer network and model dry weather flows at an urban catchment scale. This application of MODFLOW requires representing, in a simplified way, the interactions between the soil and the sewer trench, which acts as a drain. Observed average groundwater levels were satisfactorily simulated by the model while the baseflow dynamics is well reproduced. Nonetheless, soil parameters resulted to be very sensitive, and achieving good results for joint groundwater levels and baseflow was not possible.

Manufacture of full-scale geopolymer cement concrete components: A case study to highlight opportunities and challenges

PCI Journal ◽  
2015 ◽  
Vol 60 (6) ◽  
pp. 39-50 ◽  
Author(s):  
Brett Tempest ◽  
Clarke Snell ◽  
Thomas Gentry ◽  
Maria Trejo ◽  
Keith Isherwood
Keyword(s):  
Full Scale ◽  
Cement Concrete ◽  
Geopolymer Cement

Side effects of cultured bacteria addition in wastewater collection system on plant operations – a case study

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
Yanjin Liu ◽  
Giraldo Eugenio
Keyword(s):  
Energy Use ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Collection System ◽  
Oil And Grease ◽  
Odor Control ◽  
Plant Operations ◽  
Cultured Bacteria ◽  
Wastewater Collection

Cultured bacteria addition is one of the technologies used for odor control and FOG (fat, oil, and grease) removal in wastewater collection systems. This study investigated the efficiency of bacterial addition on wastewater odor control by conducting a set of full scale trials in a 60,000 cubic meter per day system for a period of two years. The objectives of this study were: (i) to identify factors that could impact wastewater treatment plant (WWTP) operations due to the effect of bacterial addition in the collection system, (ii) to estimate/understand the level of those impacts, and (iii) to present some interesting findings from the completed case study. The plant operation data before and during the bacterial addition were reviewed. The application of the cultured bacteria presented in the study was found to have significant impacts on the operation of the WWTP in terms of influent biological oxygen demand (BOD) and total suspended solids (TSS) loading, primary settling, sludge production, energy use, dissolved sulfides concentration, and methane production.

Sediment transport under dry weather conditions in a small sewer system

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen
Keyword(s):  
Sediment Transport ◽  
Field Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sewer System ◽  
Transport Models ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Initial Results

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).

Pollution based real time control strategies for combined sewer systems

1997 ◽  
Vol 36 (8-9) ◽  
pp. 331-336 ◽  
Author(s):  
Gabriela Weinreich ◽  
Wolfgang Schilling ◽  
Ane Birkely ◽  
Tallak Moland
Keyword(s):  
Real Time ◽  
Control Strategies ◽  
Ammonia Nitrogen ◽  
Simple Extension ◽  
Real Time Control ◽  
Time Control ◽  
Sewer Systems ◽  
Receiving Waters ◽  
Tunnel System

This paper presents results from an application of a newly developed simulation tool for pollution based real time control (PBRTC) of urban drainage systems. The Oslo interceptor tunnel is used as a case study. The paper focuses on the reduction of total phosphorus Ptot and ammonia-nitrogen NH4-N overflow loads into the receiving waters by means of optimized operation of the tunnel system. With PBRTC the total reduction of the Ptot load is 48% and of the NH4-N load 51%. Compared to the volume based RTC scenario the reductions are 11% and 15%, respectively. These further reductions could be achieved with a relatively simple extension of the operation strategy.

Investigation of planing craft maneuverability using full-scale tests

2021 ◽  
pp. 147509022110303
Author(s):  
Kazem Sadati ◽  
Hamid Zeraatgar ◽  
Aliasghar Moghaddas
Keyword(s):  
Full Scale ◽  
Performance Characteristics ◽  
Forward Speed ◽  
Speed Reduction ◽  
Planing Craft ◽  
Full Scale Tests ◽  
Turning Maneuver

Maneuverability of planing craft is a complicated hydrodynamic subject that needs more studies to comprehend its characteristics. Planing craft drivers follow a common practice for maneuver of the craft that is fundamentally different from ship’s standards. In situ full-scale tests are normally necessary to understand the maneuverability characteristics of planing craft. In this paper, a study has been conducted to illustrate maneuverability characteristics of planing craft by full-scale tests. Accelerating and turning maneuver tests are conducted on two cases at different forward speeds and rudder angles. In each test, dynamic trim, trajectory, speed, roll of the craft are recorded. The tests are performed in planing mode, semi-planing mode, and transition between planing mode to semi-planing mode to study the effects of the craft forward speed and consequently running attitude on the maneuverability. Analysis of the data reveals that the Steady Turning Diameter (STD) of the planing craft may be as large as 40 L, while it rarely goes beyond 5 L for ships. Results also show that a turning maneuver starting at planing mode might end in semi-planing mode. This transition can remarkably improve the performance characteristics of the planing craft’s maneuverability. Therefore, an alternative practice is proposed instead of the classic turning maneuver. In this practice, the craft traveling in the planing mode is transitioned to the semi-planing mode by forward speed reduction first, and then the turning maneuver is executed.

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