Category Archives: Wastewater Treatment Process Technologies

Industrial Wastewater Disposal and Treatment Options – Back to Basics – A Practical Approach from KEE Process Limited

What are the Options

Brewing, winery, soft drinks manufacture, food preparation production and packaging (baking, ready convenience meals, abattoir, meat, poultry and vegetable), dairy (milk processing, cream, cheese and yoghurt production), commercial laundries, pharmaceutical, petrochemical and many other industries are large users of water. This results in large quantities of heavily polluted wastewater for disposal.

UK Water companies and the public bodies responsible for collection, drainage and treatment of wastewater have strict controls on the quantity and the quality of industrial and trade wastewater being discharged into public sewers. Legislation supports them in this. Direct discharge to a watercourse is even stricter and is normally monitored by the National Environmental Agencies and the Environment Agency in the UK. Penalties for transgression can include prosecution, fines, financial loss and can, in some cases, prohibit operations.

Industrial wastewater discharge disposal options

Audits

It is always advisable to carry out an evaluation of the processes involved in the core business of an organisation to identify sources of wastewater. An audit would help reduce waste/wastewater and disposal costs, quantify flow rates, solids and organic loads and characterise the wastewater to provide the necessary data for analysing the available disposal options and optimise the design of any on-site treatment plant.

It is useful to be subjective when carrying out an audit to ensure that good housekeeping practices are identified to reduce unnecessary waste which would add to the costs of disposing wastewater generated on site. Process audits should be aimed at identifying the waste, excess use of water and energy. Simple actions, such as installations of energy-saving devices or taps and hose controls and careful disposal of solid waste, can produce both financial and environmental benefits. It would also help to reduce the size of an on-site treatment plant if one was planned and this would result in capital cost savings.

An audit would lead to evaluation of volumetric and organic mass loads for design purposes and would aid in characterising the nature of the waste, to optimise the design for on-site treatment plants.

Public Sewer or Watercourse

Public sewers are convenient for disposal if nearby. Quantity, strength and characteristics of the wastewater need to be considered and consented by Authorities or the Water Company in the UK. If approval is granted and the wastewater meets the criteria set, then sewer disposal would be an obvious choice, but this comes at a cost. High COD (Chemical Oxygen Demand) and suspended solids would lead to high costs in discharging to sewer and reducing these parameters could make significant savings. Partial or full onsite treatment would bring about cost savings to sewer discharge but needs justifying through quantification.

Hygiene versus Convenience

With the food processing, beverage and dairy industry, hygiene is of paramount importance. On-site wastewater treatment may be perceived by management as presenting problems although the risks are small. It is vital that the Operatives normally involved in the process part of the industry, do not need to visit the wastewater treatment plant and the risks to main operation therefore are contained and the operation of the wastewater plant becomes one of non-core features. This can be achieved by having the treatment plant operation undertaken by the maintenance department of the industry or independent operators such as KEE Process Limited who would provide a turnkey solution for designing, supplying, installing and operating a plant for a Client.

Treatment Options: Physical, Biochemical or Combination of Both

Where the decision to treat on-site has been made, the appropriate choice of plant has to be determined. Whether partial treatment or full treatment is installed is usually a matter of economics. A capital outlay is necessary and this must have an acceptable payback period. The treatment options available are Physical, Physical/Chemical, Biological or a combination of all or any of these.

On-site treatment could involve simple physical treatment to remove materials such as gross solids, FOG (Fat, Oil & Grease) and can include pH correction. The equipment may include manual or mechanical screens, grease separators or the newly introduced DISPERSED AIR FLOATATION which is simple, economical and extremely efficient and effective. A component of COD associated with these materials would also be removed by the physical treatment. With DISPERSED AIR FLOATATION up to 30% BOD, 50% COD, 60% TSS and over 90% FOG can be removed physically without the use of chemicals. Better performance can be achieved by using coagulant, flocculants and ploy-electrolytes. In most cases, partial treatment using DISPERSED AIR FLOATATION would achieve the reduction in pollution loads necessary to substantially reduce the cost of discharge of effluent to public sewer. The ownership costs (capital expenditure, servicing, maintenance and operation costs) associated with DISPERSED AIR FLOATATION are usually low. The benefits of cost savings in effluent disposal are high and the capital/operating cost of proving on-site partial treatment can be justified against the ownership costs. Given these benefits it may be sufficient not to invest in further onsite treatment for the effluent to be discharged into public sewer.

However, it may still be necessary or even desirable for the wastewater to be treated further for direct discharge to a watercourse or re-used for non-process operations within the industry. In such a case, full on-site treatment would often justify the capital and operations cost. Cost analysis must also take into account the valuable space required for location of the treatment plant on the core business site.

For disposal to watercourse, consent from the Environmental Regulating Authorities (the Environment Agency in the UK) will be necessary.

KEE Microfloat Unit Interior working of the Microfloat System

The full treatment options could include anaerobic fixed film technology. This is particularly suitable for high strength wastewater requiring initial partial treatment prior to sewer disposal or further aerobic treatment to produce effluent suitable for direct discharge to a watercourse. The aerobic process could include:

Suspended Growth Activated Sludge Process options through Extended Aeration, Sequencing Batch Reactor (SBR) or Oxidation Ditch.
Fixed Film Process through Rotating Biological Contactors (RBC), Submerged Aerated Filter (SAF).

Choosing the Treatment Option

The most suitable process selection would depend on many factors such as:

Initial Mechanical/Electrical Capital Cost.
Installation Cost.
Operating Cost including on-site attendance/labour costs, energy costs, consumables and plant operation complexities. Disposal costs of physically separated pollutants e.g. FOG, TSS and sludge in case of full Biological treatment plant.
Servicing, Spares & Maintenance Cost.
Space and Land requirements for location of the on-site treatment plant.

All the above factors should be taken into account and a discounted cash flow calculated on a 10, 15 or a 20-year replacement cycle. This should be weighed against the cost of disposal to sewer or partial treatment followed by disposal to sewer. When evaluating the disposal costs to public sewer, it is necessary to liaise with the authorities or provider of the central wastewater treatment plant, to establish initial capital cost contribution expected and the potential annual costs associated with sewer discharge over the next 10,15 or 20 years. Armed with all this financial data, the overall cost of various disposal options should be evaluated and the financial disposal option chosen justified on a payback period or the net discounted cash flow, or the simple approach of evaluating the cost of disposing a unit volume (say 1 m3) of effluent.

With so many factors to consider, such as type of treatment, if any, the process selection for partial or full on-site treatment and cost analysis to justify the most appropriate option for disposal of the effluent, it may be beneficial to use the services of a professional. An experienced independent consultant with a wide knowledge of industrial wastewater treatment processes would be the obvious choice. Some Companies do offer a wide spectrum of process options and have the necessary experience to offer turnkey solutions using the most optimised process. Such companies may have a bias towards their own technology and process if they have a limited range of process options to offer. All this should be balanced against their ability to provide project management, process design, site civil work, mechanical/electrical erection, commissioning and more importantly on-site operation with process warranties.

The KEE Group Companies, KEE Process Limited and KEE Services Limited can offer such an option. Their technologies include physio-chemical processes (Dispersed Air Floatation, simple gravity solids and grease separators), Anaerobic Reactors (for high strength wastewaters), Fixed Film (RBC and SAF) Reactors and Suspended Growth Reactors (Activated Sludge Processes such as Extended Aeration, SBR, Oxidation Ditch, Extended Aeration followed by Ultra fine Filtration), and on-site operation of the treatment plant. KEE also have a team of experienced process engineers and project engineers capable of delivering the necessary turnkey solution to suit most customers. KEE Services offer on-site plant operation with out-of-hours emergency backup through a 24hrs manned Call Centre.

RBC Modular System

Photographs showing SAF, RBC, & SBR plants below:

Cut-away view of the KEE EnviroSAF

Oxidation Ditch with Nitrification, Denitrification and Aerobic Sludge Digestion.

Large RBCs for biological treatment.

Compact, single piece NuDisc® RBC Wastewater Treatment System.

The decanter and access manway of a fruit juice wastewater treatment SBR Plant.

Vegetable processing wastewater screening prior to being treated in a multi-stage Submerged Aerated Filter Plant.

Sequencing Batch Reactor (SBR) plant at a Brewery.

KEE Multi-stage Submerged Aerated Filter Plant.

Multi-stage Submerged Aerated Filter Plant. Preliminary treatment includes screening.

For more information on KEE’s latest NuDisc^®RBC, please **visit our website or call KEE Process on: 01296 634500**

KEE collaborate with Northern Ireland Water on a £5m investment to construct one of the largest RBC sites in Europe.

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KEE’s expertise in design, manufacture, installation, servicing maintenance and operation of equipment for all types of wastewater treatment plants is backed by over 60 years of experience and over 350,000 installations worldwide.

Background

KEE have been working with Northern Ireland Water (NIW) for over 15 years, providing treatment plants for many of their water infrastructure projects. The most recent collaboration involved KEE Group working on a new £5 million wastewater system for 5,800 people at Keady, Co Armagh. The new Keady Wastewater Treatment Works was to deliver improvements in process efficiency, discharge quality and increase the capacity of the plant to encompass the neighbouring population in Armagh.

KEE technical experts worked closely with NIW consultants throughout the term of the project, providing the following:

Support and guidance in selecting the correct treatment process and technology
Detailed 3D plant designs and specifications
Manufacture and supply of wastewater treatment equipment
On-site training for NIW Services Staff, to ensure optimum plant process performance and extended life
On-going site maintenance and back up support

The Challenge

The new plant was to meet the following requirements:

To be constructed within the existing site of the old plant
Achieve current and future NI Environment Agency discharge standards and EU regulations.
Provide additional capacity to meet the future needs of the growing local population

10 KEE RBCs at the new Keady Wastewater Treatment Works

The Solution

The consistent performance of KEE’s RBC technology installed in Derrylin back in 2010 gave Northern Ireland Water the confidence to proceed with the Keady project.

The new plant was installed in the Autumn of 2012 and consisted of a Tertiary Slow Gravity Sand filter and 10 RBCs (Rotating Biological Contactors).

Each RBC was housed in a precast concrete chamber with GRP top covers to protect the equipment from the weather and enable easy access for maintenance. The upgrade in technology achieved NIW’s current and future consent and capacity requirements and delivered the following additional benefits:

New RBC Plant Performance at Keady

Final effluent Target Actual

BOD <5.00mg/l    4.96mg/l
SS    <10.00mg/l    10.00mg/l
NH₄-N    <1.50mg/l    0.23mg/l

95% ile compliance basis.

Keady WwT Works, Large Diameter RBCs under construction.

Design Features

Robust and consistent performance during Winter and Summer periods, ensuring discharge consents are met all year round.
Substantial underground installation to minimise the visual and environmental impact on the landscape.
Thermostatic temperature control system inside each RBC unit to mitigate sub zero ambient temperatures.
Innovative KEE ‘flow control’ mechanism fitted to each RBC to enhance process stability.

Cost Savings

30 years design life, 20 years warranty on structural components.
£812,520 energy saving and associated carbon footprint over 20 years.
£947,200 OPEX saving due to reduced operational, maintenance, labour, spares and sludge disposal costs over 20 years.
30% saving in CAPEX costs when compared to an equivalent sized ASP (MBR) system.

Keady Wastewater Treatment Works is just one example of the many projects being undertaken by NI Water and KEE to improve infrastructure in Northern Ireland. These projects represent part of a £490 million investment by NIW in wastewater services throughout the North over the past three years.

For more information on KEE’s latest NuDisc^®RBC, please **visit our website or call KEE Process on: 01296 634500**

KEE design upgrade solution for Anglian Water using NuDisc® Technology

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“ I had not personally worked with KEE before and I was impressed with their ingenuity and their unwavering commitment to deliver the upgrade at Brinkley on time and to a high standard. It is refreshing to work with a company that do not have a ‘fit and forget mentality’ and have a genuine passion for the service they give their customers. If ever I need some expert advice or another Waste Treatment Plant, I will not hesitate to contact KEE. ” Gavin Pipe Anglian Water.

Background

KEE have been working with Anglian Water for over 30 years and were commissioned to design and install the original B16 Rotating Biological Contactor (RBC) at their Brinkley site back in 1983. Following mechanical failures well past the 30 year manufactured design life of the plant, Anglian Water knew 3 years on, that the site was in need of re-furbishing. Therefore they installed a temporary SAF Treatment Plant to be set up on site to treat the waste whilst they sourced and installed a replacement RBC.

Unfortunately the temporary SAF Plant kept ‘tripping out’ and proved unable to treat the effluent to the correct consent levels so Anglian Water had no option but to have the effluent removed from site manually using tankers.

The Challenge

At this point Gavin Pipe, Project Engineer for Anglian Water at Brinkley contacted KEE to arrange a site survey and quote for a new RBC replacement. Upon arriving on site, KEE noticed that Magnasol was being used to neutralise ammonia from the B16 discharge in order to achieve the required environmental consent levels. It was therefore clear that the old plant was not achieving today’s environmental standards without chemical intervention.

Anglian Water , Brinkley

The Solution

KEE recommended upgrading the old RBC with KEE’s latest NuDisc^® Design Technology. The proposed refurbishment included the following benefits:

NuDisc^® technology delivering substrate and flow balancing
20 years extended life of the plant for a third of the cost of a new plant
Elimination of chemical dosing resulting in a cost saving of £3,800 p.a
Reduction in the need for de-sludging and tankering from site, therefore minimising tankering costs, heavy traffic and noise through the residential estate
3 day refurbishment installation program, providing huge savings in project management, human resource, and re-build costs when compared to a new installation
Chemical free solution, protecting the environment

Anglian Water, Brinkly

Anglian Water agreed to KEE’s proposal and the new RBC was installed on the 26th of September. The installation took the scheduled 3 days to complete and the Brinkley site is now back in full working order, benefiting from the very latest solutions in mechanical engineering and process technology.

For more information on KEE’s latest compact, self contained NuDisc^®RBC, please call KEE Process on: 01296 634500 or visit the KEE Group website.

KEE uses ‘Fixed Film’ technology to meet Northern Ireland Waters’ discharge standards at Derrylin.

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“I have experience in other process technologies which can easily facilitate these standards but at an ever increasing cost. I essentially needed something which had been tried, tested and trusted and I was more than satisfied to engage KEE Process to meet these demands”
Michael McAlary, Northern Ireland Water.

Background

In 2006, Northern Ireland Water (NIW) commenced a project to invest in a new Wastewater Treatment Plant at Derrylin.

Their NIW Project Managers and Process Engineers were tasked with finding a suitable process to achieve the discharge standard set down by the NIEA. Having previously worked with KEE Process as their ‘Framework’ partner for Western & Southern Division RBC Framework, the Project Team selected KEE to assist.

The Challenge

KEE Process was commissioned to design a wastewater treatment system to meet the following criteria:

To consistently achieve the consented final effluent standard with a consent of less than 5mg/l BOD and Suspended Solids on a 95 percentile basis.
To incorporate the process capability to treat future forecasted waste flows and loads predicted for 2010.
To ensure that the treatment capacity could be expanded further (by almost 50%) to manage the forecasted 2035 increase in flows and loads, whilst still maintaining performance objectives.

The Solution

Fixed Film technology offered the best solution in the form of five Rotating Biological Contactors (RBCs) to meet their design criteria. The RBCs not only delivered the consistent performance they were looking for but also offered the lowest lifetime costs and carbon footprint when compared to all other wastewater treatment options available.

Together with the NIW Project Manager, Technical Advisers and Consultants, KEE Process designed a plant which featured ‘modular phased construction’ to minimise on-site workload and concrete tank construction. The new plant was built and commissioned during 2009 and has since then consistently achieved consent standards and delivered considerable savings in capital costs, operational labour costs and energy.

Final Effluent Consent vs New System Performance

Final effluent Target Actual

BOD <5.00mg/l 2.00mg/l
SS <10.00mg/l 5.00mg/l
NH₄-N <3.00mg/l 0.01mg/l

95% ile compliance basis.

Plant Equipment

Two 6m diameter, prefabricated hopper-bottomed GRP Primary Settlement Tanks were installed, with fully automated sludge and scum draw-off facility.
Five prefabricated RBCs, housed in GRP tanks with hinged sectional insulated covers.
Three 6m diameter prefabricated, hopper-bottomed GRP final settlement tanks, with fully automated sludge and scum draw off facility.
Final discharge was fed into slow gravity sand filters for polishing up the effluent to reduce suspended solids.

Design Features

A ‘flow splitting’ mechanism was installed to give Process Engineers the ability to channel the wastewater flow through the treatment process in different ways to achieve (a) optimal plant performance and (b) provide the flexibility to construct or expand the plant in phases as and when required.
Each RBC consisted of four treatment stages, designed to remove all soluble BOD and Ammoniacal Nitrogen to provide the final effluent BOD on a 95 percentile basis.
An internal ‘recycle system’ was incorporated to optimise the biological stage, the settling character of the fine solids and control of nitrogen from the plant.

Simple Maintenance and Low Lifetime Cost

A 30 year RBC design warranty and 20 year warranty on all structural components minimised the lifetime costs of the new plant.
The self-regulating biological stage of the RBCs required very little operational input and maintenance.
Simple RBC mechanical maintenance schedule consisting of a 6 monthly lubrication change for bearings and biennial lubrication.
Energy consumption of the RBCs was reduced and installed with a rating of only 1.5kW per RBC, resulting in a demand power consumption of 0.8kW on a continuous basis.
The RBC Drives were manufactured for a 50 year average lifespan, reducing lifetime costs even further.

Lifetime Cost Savings

NIW reviewed other wastewater treatment works and completed a case study and cost analysis based on a 7.000PE plant. Compared to other process technologies designed for a 30 year life-time, the RBC system provided:

£317,185 cost saving in power.
£272,420 cost saving in maintenance, operational labour, sludge disposal, and replacement parts.
Total OPEX life-time saving of £589,605 over 20 years.

“In today’s economic climate Northern Ireland Water are looking at ways of reducing life-time plant costs whilst meeting ever tighter environment consent standards as agreed and published by the local Environment Agency (NIEA). I needed a simple, easy to maintain process in order to meet these requirements.

The RBC offers a very robust process, achieving good consistent discharge standards, requiring minimum operational and maintenance input and very importantly, low power consumption. This has given me the confidence to accept the RBC process for Derrylin where consistent and tight effluent quality was stipulated by the NIEA”.
Michael McAlary, Wastewater Services Manager, Northern Ireland Water.

For more information about the Wastewater Treatment Process Technology and the Sewage Plant Maintenance Services the KEE Group offer, please call our team on
01296 634500 or visit our KEE Group website.

KEE Expert – Tankering and De-sludging Process Explained

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To keep your wastewater treatment system in good order and operating efficiently, it is important to remove the accumulated ‘sludge’ from the plant on a periodical basis.

So how regularly does your plant require de-sludging?

There are two factors that require consideration before answering this question.

The size of your plant and the number of people it serves
How thoroughly the ‘de-sludging’ process is undertaken

Generally speaking a plant servicing a single house will require de-sludging once a year.
For larger units, the de-sludging schedule will depend on the inlet flow rate and the type of wastewater being treated. Your local KEE Engineer or our Customer Service Team will be able to advise you in this instance.

If your plant is not de-sludged properly when required, the silt and sediment in the bottom of the Primary Settlement Tank (PST), Final Settlement Tank (FST) and the floating crust on the top of these tanks will build up over time and cause performance issues and possible odours. Additionally incorrect de-sludging can damage the internal Baffles and Drive components resulting in expensive and unnecessary repairs.

De-sludging Process

Break up the surface crust floating in Primary Settlement Tank (figure 1 and 2) and remove the floating crust solids with the suction hose.
Skim off and remove the crust floating in the FST (figure 3).
Put the hose back into the Primary Settlement Tank and push it right down to the bottom of the tank. Frequently move the hose along the length of the tank to ensure all the settlement sludge is removed.

We recommend your plant is de-sludged approximately 7-10 days before your KEE Engineer is scheduled to complete a routine Maintenance Service.

For more information or to arrange a tankering visit, please call our KEE Services team on 01296 634500 or visit our KEE Services website.

KEE design and manufacture extended NuDisc® 2000 RBC Installation for Spanish Village.

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“Fullgas are delighted that the installation of KEE’s NuDisc^® RBC was completed on Monday without a single glitch. All the components fitted into place perfectly and we thank KEE for their expertise, attention to detail and commitment to the successful completion of this project.” Pablo Cepeda, Fullgas.