Parsons Waste Water Treatment |
Increasing awareness of Environmental issues has lead to increasing pressure on Water Companies to eliminate Odourous discharges to atmosphere. Parsons, drawing on their expertise gained over 30 years in the treatment of highly corrosive, toxic and carcinogenic gas phases have designed and installed numerous Odour Abatement systems utilising Wet Chemical Scrubbing, Carbon Adsorption Technology and are a founding Licensee of the Odorgard™ technology originally developed by ICI now Synetix. The Odorgard™ Chemical absorption system utilises a nickel-based catalyst to enhance the absorption of Hydrogen Sulphide and Mercaptans, which are the principle, compounds encountered in Sewage Works. The use of Odorgard™ reduces the chemical consumption and minimises the equipment demands.
Parsons have designed, manufactured, installed and operated Odour Abatement Systems for a wide range of process duties with inlet concentrations as high as 2000 parts per million (ppm) reduced to less than 80 parts per billion (ppb), the Odour Threshold for Hydrogen Sulphide. All systems carry a tangible process guarantee are normally based on measured discharges from the exhaust stack.
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The collection of odourous gases from treatment works is the key to effective odour control and to this end Parsons are able to provide odour monitoring/surveying services and then once the site has been surveyed the results can then be used to form the basis of a site model. Utilising the latest computational fluid dynamic modelling techniques Parsons are then able to design integrated ventilation schemes which ensure all odours are collected effectively and utilise novel collection protocols developed in the Cleanroom Industry which results in air volumes being minimised thus leading to reduction in equipment size and capital/operating costs. Naturally reducing air volumes leads to higher inlet concentrations but effective design means that such equipment performance demands fall well within the performance capabilities of Parsons Scrubbing Systems and as the equipment size is smaller capital and operating costs are significantly reduced.
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Full Site Surveys using All Station Lasers linked to AutoCAD |
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Supporting/Access Steel Structures |
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Front End Design Study |
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Civil Requirements |
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Odour Mapping |
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Site Surveying |
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Odour Modelling using Computational Fluid Dynamics |
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Construction Management |
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Process Engineering |
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Installation |
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Mechanical Engineering |
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CDM Compliance |
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Exhaust Ductwork Design |
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Documentation |
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Commissioning |
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Handover |
The above list details the full services offered by Parsons and the client can select which elements they wish Parsons to provide and which they prefer to resource in-house, clear identification of responsibilities at an early stage of a project ensures project completion on time and on budget.
Parsons are equally experienced on Greenfield site projects, or replacement of existing equipment within a working production facility, both represent challenges. The importance of accurate site surveying is just as important in all cases. Parsons utilise state of the art “All Station” laser measuring devices, which are used by experienced engineers who then download the information into a 3D AutoCAD image that forms the basis of the design. Once the site survey has been completed the normal mechanical and process engineering procedures are undertaken to produce manufacturing drawings, during manufacture in Parsons factory the vessels are regularly inspected and dimensional laser checks are carried out and overlaid onto the site General Arrangement Drawings to ensure accurate interfacing.
The Scrubbing vessels tend to be manufactured from 6mm PP reinforced externally with GRP; various resin systems are used to accommodate process design requirements in respect of heat distortion and chemical resistance. In certain cases PP is not recommended and so as alternatives Parsons offer PVDF, ECTFE, FEP and PFA although these materials tend to be thinner.
Generally system pressures fall in the range of 1000 Pa to 6000 Pa and so corrosion resistant fans form an integral element of the system, Parsons manufacture a full range of corrosion resistant fans.
Small scrubbing packages can be skid mounted, which enables the scrubber to be installed within a coated mild steel framework giving access to all parts of the scrubber for the purpose of maintenance. The recirculation pumps, pipe work, ductwork, instrumentation and control panels are all mounted within the skid, fully installed and tested in our works so that all commissioning can be done off site. This facility reduces cost and installation times on site and is a design option that has been used many times by clients both in the UK and Overseas.
On larger scrubber installations Skid mounting is not practical however Parsons have lead the way in skid mounted Recirculation systems which again minimises site installation time and cost. |
The importance of maintaining environmental equipment in optimum performance requires specialist expertise and in certain circumstances Water companies prefer to contract out such services and to this end Parsons are able to install and operate on a clients behalf the Odour Abatement system thus eliminating the day to day responsibility from the Water Company and the need to maintain a specific engineering resource.
Parsons are able to monitor remotely the plants and thus benefit from better time management of expertise and resource which leads to real cost savings. The client obviously benefits from a fixed monthly cost for the period that can run for 1 to 5 years and eliminates all Capital Costs and unknown maintenance obligations.
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No Capital Commitment |
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Tax Efficient |
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Flexibility to Upgrade |
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Fixed Cost for the entire period 1- 5 year contracts available |
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Frees up valuable Engineering Supervision/Support |
Plastic Ductwork systems can be quite complex on larger Treatment Works site’s and reliable flow control and isolation are demanded for safe plant operation to eliminate leaks which can result in non compliance issues with planners and local residents.
Parsons manufacture a full range of manual and actuated dampers for flow control and isolation purposes to complete their ductwork programme. The ductwork programme ranges in size from 110 mm diameter up to 3000 mm diameter is available in PVC or Polypropylene reinforced where required with GRP, a range of corrosion resistant attenuators and stacks completes the complete system.
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Parsons who manufactures a wide range of plastic storage vessels and reactors also caters for the storage and processing of chemicals.
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PVC |
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Polypropylene |
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Acrylic |
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PVDF |
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ECTFE |
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FEP |
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PFA reinforced externally where required with GRP. In accordance with standards such as ASME X and DVS 2205 are also available on request. |
Vessels are available in rectangular/square styles in complete or sectional design, where space or processes prefer circular vessels up to 4.5 metres diameter 18 metres tall can be produced. Circular vessels tend to be vertical axis but if preferred Parsons can supply Horizontal axis vessels complete with support cradles. Full delivery, installation and commissioning services are available using our own experienced site technicians supervised by our Qualified Engineering Staff.
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Totally enclosed or lids |
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Lagging |
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Man way Entrance Points |
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Access Ladders |
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Hold Down Feet |
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Tanker Filling Pipework |
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Lifting Lugs |
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Discharge Pipework/ Metering/Distribution Systems |
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Nozzles |
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Storage Bunds |
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Contents Gauges |
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Remote Alarm Systems |
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Heaters |
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Chemical Dosing is an important element of any Gas Scrubbing Installation but as a specific element Parsons are able to design bespoke Chemical dosing packages to suit any application such packages can be skid mounted, pre piped and wired and supplied with dosing/metering pumps pH and Redox control loops and dosing/distribution manifolds.
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