Tag Archives: sewage treatment repairs

KEE SERVICES LIMITED – REFURBISHMENT OF EXISTING TREATMENT SYSTEMS FOR IMPROVED PROCESS PERFORMANCE AND REDUCED LIFETIME COSTS

KEE Refurbishment of Packaged Treatment Plants

The Anglian Water Systems (AWS) Team undertook such an exercise over a range of small to medium sized treatment plants adapted by the plc from a local council. Instead of abandoning the existing works, KEE Services Ltd with support from their process partners, KEE Process Ltd, were commissioned to survey 11 sites and report the findings. The report was required to include inventory register, feasibility of refurbishment, process implications and improvements with the associated costs of refurbishment. The survey was undertaken and completed over four weeks and a complete report, with a costed refurbishment program for all the sites was submitted to the AWS Team.

The 11 plants varied from 40PE up to 500PE in size and included systems required to reduce BOD and, in some instances, provide fully nitrified discharge with less than 5mg/l ammoniacal nitrogen. All the plants surveyed were of packaged plant construction, single piece or modular, and included primary settlement stage with combined sludge storage, RBC type biological stage and final settlement tank. The report concluded that it was feasible to refurbish all the plants and included a program for refurbishing the plants to a standard where the operators would have the confidence that the plants would provide a reliable and useful life for a further 20 years. Depending on the extent of refurbishment work necessary, the costs associated with the refurbishment varied substantially, but in every case it was much cheaper than replacement. The cost of refurbishment included for supply and installation of new equipment.

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This relates to a cluster of small population equivalent installations where all the plants upgraded were over 20 years old and would now have in excess of a further 20 years life and an improved process performance. With all the sites, the outer GRP structure housing the plant was retained and, with the exception of one or two sites, the internal components including the RBC were replaced by brand new factory built units incorporating the latest concepts in mechanical, structural and process engineering.

All the above plants include sectional GRP covers and were replaced to provide the equivalent of a new plant without the high cost and resource required to build one.

Refurbishing Large Wastewater Treatment Works

The KEE refurbishment concept can also be applied to plants serving larger populations which can be electro-mechanically upgraded to show similar benefits and add 20 years or more useful life to the plant. Scottish Water undertook a similar exercise where an existing 4,750PE activated sludge plant needed to be refurbished to bring the plant back to its full performance requirement without necessarily having to re-build the works.

For more information on Wastewater Treatment Plant refurbishment call KEE Services on: 01296 634500 or visit the KEE Services website.

KEE TRITON AERATOR/MIXER OVERCOMES PREVIOUS LIMITATIONS OF OXIDATION DITCH TECHNOLOGY

KEE FINE BUBBLE AERATION WITH BUILT IN MIXER

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KEE Process Triton

The KEE Triton Aerator/Mixer overcomes the previous limitations of oxidation ditch technology and can be used to revitalise existing oxidation ditches and extended aeration plant or systems based on activated sludge process.

Using the dual mode processor capabilities of Triton Aerator, aeration basins up to depths of 10m can be completely aerated and mixed. Existing Oxidation Ditches (OD) can be retro-fitted and new OD plants benefit with much smaller footprint. Nitrification and denitrification can all take place in a single reactor. With two propellers and a regenerative blower, Triton is able to operate either as an anoxic mixer with the blower turned off, or an efficient aerator/mixer with the blower on.

Multiple Triton units can be arranged to provide extended contact time between air bubbles and water stream, with greater oxygen transfer efficiency. Improved biological treatment results in Biochemical Oxygen Demand (BOD) removal rates as high as 99% in highly contaminated wastewater.

The KEE Triton is the most versatile fine bubble aeration/mixing device for activated sludge treatment systems available with dual functions – aeration and mixing.

KEE fixed price operation and maintenance contracts are available.

For full information on KEE Technologies and Services visit: KEE Fine Bubble Aeration
or call KEE on: 01296 634500

KEE SERVICES LIMITED MAINTAIN WASTEWATER AND SEWAGE TREATMENT EQUIPMENT MADE BY ANY MANFACTURER

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The maintenance and operation of any wastewater treatment equipment is a specialised task and KEE Services Limited recognises this.

KEE, with its extensive experience of on-site servicing of all types of wastewater treatment and pumping equipment, its technicians have the knowledge necessary to protect its customers’ investment and the environment.

KEE Services offers planned maintenance programmes ranging from an annual visit to full plant operation. Its aim is to respond to all of your urgent servicing and maintenance needs. The KEE Services Team of fully trained Technicians operates on both a local and regional basis to ensure a prompt and reliable service.

  • Emergency Services
  • Planned Maintenance
  • Breakdowns
  • Equipment Refurbishment
  • Plant Operation
  • Spares
  • Ancillary Products

Committed to maintaining your environment

KEE Services Ltd offers Preventative Maintenance, Process Operation and Breakdown Services for all types of treatment plant and pumping equipment, from all manufacturers. KEE Services Ltd supports its UK customers during out-of-hours emergencies by offering a 24-hour manned call out service.

KEE Technicians are trained in long-term servicing and look after over 8,000 installations in the UK. They have sound mechanical and electrical experience, combined with application knowledge, and can identify problems early.

Working on a local basis, KEE technicians give a prompt service and have a good understanding of the conditions and legislations in each area.

Service and maintenance contracts include routine visits to keep equipment from both KEE Process and other manufacturers in top condition and prolong its lifespan.

There is a range of contracts available or a package can be designed specifically. If refurbishment or upgrading is necessary, KEE Services can advise on the alternatives. Site assessment can be made and installations planned for new and existing sites.

For full information visit the KEE Services website or call 01296 634500 to arrange a visit.

 

KEE PROCESS LIMITED HAVE DEVELOPED A NEW SINGLE-PIECE FACTORY BUILT WASTEWATER TREATMENT PLANT TO ADD TO THEIR RANGE

Developed by KEE the NuDisc© 5000 HD RBC Sewage Plant and Treatment Centre – a new single-piece factory-built plant to add to their range to meet Severn Trent Water’s extremely stringent requirements.

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Situated in the heart of the Peak District, the village of Hassop in north Derbyshire lies approximately 11 miles east of Chesterfield and 2 miles to the north of Bakewell, and is within the Severn Trent Water’s catchment. The properties subject to the Section 101a application were served by a village drain. This received flows from septic tank high level overflows and discharged to a local un-named watercourse. Local ground conditions were unsuitable for soakaways. Hassop Estate applied, under Section 101a of the Water Industry Act 1991 in December 2007, for a public sewerage system to be provided.

In 2010 STW accepted the need to lay new sewers and treatment system. The new wastewater treatment works was required to treat flow from a population equivalent of 210, and the consent to discharge for this site required that the BOD < 20mg/l, SS < 30mg/l and NH4-N < 5mg/l.

Project background and cost considerations
The construction of the Hassop WwTW involved the laying of approximately 1600m of foul sewer, an intermediate pumping station and a new RBC Unit to serve the Village. The work was undertaken by NMCNomenca as the Tier 1 Framework Partner and as part of S101A Scheme for Severn Trent Water Ltd.

NMCNomenca’s scope of works was for the detailed design, construction and supervision of the whole project from start to finish. NMCNomenca were also in control of the site until handed back to Severn Trent Water Ltd after commissioning and testing.

The project for capital delivery had to take into account CAPEX and OPEX costs to determine lifetime costs for the project over 20 years. This included the capital cost of delivering the project; design, manufacture, delivery and commissioning of the process plant and all site-related costs including provisions for on-site health & safety, environment and personal welfare for site operatives. The second part of the costs related to operational costs and included cost of energy, consumables, spares, labour and process-related costs such as desludging. The overall objective for the consortium is to minimise lifetime costs without compromising any aspects of the project delivery including site work.

Consent standards
The site at Hassop required to treat wastewater from a population equivalent of 210 with design DWF of 32m3/d, FFT of 173m3/d, BOD load of 12.6kg/d, SS of 15.75kg/d and NH4-N of 1.68kg/d. The consent to discharge for this site required that the BOD< 20mg/l, SS < 30mg/l and NH4-N < 5mg/l.

Such consent standards from the Environment Agency are common for wastewater discharge to a watercourse, although for a small works with such a large variation in design flows during dry and wet weather, this does present a challenge to the designers to ensure that the plant performs to requirements under all these conditions throughout the year.

Process plant selection
KEE Process has, over the last 60 years, developed a range of plants to treat wastewater from municipal and industrial sources to similar and more stringent standards where the BOD values could be less than 5mg/l, SS less than 10mg/l, ammoniacal nitrogen less than 1mg/l, phosphorus less than 1mg/l and total nitrogen less than 15mg/l. The range from KEE includes small packaged systems for small flows, modular packaged units for larger flows and in situ constructed plants for populations larger than 5,000 PE.

For the site at Hassop, the largest single-piece factory-built plant available at the time in KEE’s range was not adequate to deal with the flows, so KEE developed a new single-piece factory-built plant to add to their range. The single-piece plant would be factory built and would take into account all the requirements laid out by Severn Trent Water in its specification and the plant would be delivered to site ready to be placed on a pre-prepared concrete slab and backfilled.

The plant would include installation of the remote desludging facilities and internal electrical wiring during the plant construction in the factory. This would, in effect, be a true ‘plug and play’ system with the objective of reducing site-related construction time and costs.

Building a plant in a factory provides a controlled environment and conducive conditions for maintaining quality standards, which are often difficult when the build is undertaken at a construction site under the prevailing conditions, which may include rain, snow, low temperatures and hazardous operating environment.

In addition, a factory-built plant would enable the duration of construction on site to be substantially reduced, as the factory-built plant can be backfilled within a day or two of being delivered. This means that the excavation is not left open for long periods and, in turn, this reduces any health and safety risks associated with working on site with deep excavations and in confined spaces. However, this may have a major impact on the project costs when plants are factory built compared to building on site.

NuDisc®
KEE NuDisc® 5000 includes the primary sedimentation stage with sludge storage, RBC for biological treatment and a hopper final clarifier, all housed in a single structural GRP housing and covered with lightweight GRP covers.

The RBC is driven by a 0.75kW geared motor at a slow speed of 1rpm and is designed to comply with all the structural and mechanical requirements stipulated by Severn Trent Water Ltd.

The FST includes a fully automated descumming and desludging system, for removal of scum and sludge at regular hourly intervals back to the primary clarifier.

The primary clarifier includes remote desludging facility and this is carried out at regular intervals of 90 days when 18.9m3 (5000 gls) of sludge is tankered away.

KEE packaged plants also include flow attenuation within the primary settlement chamber, in order to provide process stability with the large fluctuations in design flows.

The manner in which the attenuation system is organised also enables evening out peaks and troughs in organic load and this attenuation is achieved in the first stage of the biological process.

Designed and built at KEE’s factory, the KEE NuDisc® 5000 was delivered on time on a cold snowy day and was placed in an excavation ready to be backfilled all on the same day.

The plant was fully commissioned to receive flows only seven weeks from delivery – a big achievement for all the parties involved including KEE Process, NMCNomenca and the client, Severn Trent Water. All other site related matter including landscaping, electrical control gear, remote telemetry system and landscaping were completed within timescales.

Operational and maintenance requirements
The operational and maintenance requirements are desludging every 90 days, lubrication of bearings required every six months. With a daily energy consumption estimated at 21kWh/d. The OPEX costs for the site are therefore minimised.

Summary
Although KEE Process does not have comparative lifetime costs for this specific project, the costs for similar projects with other water companies have shown 30% reduction in capital costs compared to other technologies with substantial amount of site related construction and equally a large proportion of savings in operating costs resulting from savings in energy consumption and operational labour requirement.

KEE, a BSI Certified Company (IMS, QMS, OHS & EMS) offers domestic and industrial wastewater treatment solutions including lifetime operation and maintenance using RBC, SAF, SBR and Extended Aeration. With 60 years’ experience and over 350,000 installations, KEE have the expertise in design, build and operation of all wastewater treatment plants.

For full information on KEE Technologies and Services visit the KEE Group website: