WSAA Infrastructure News
Including: Materials, Standards, WSAA Codes, Quality, Appraisals, Meters, Valves and other interest items
Issue No. 8 Website: www.wsaa.asn.au 15 June 2003
Inside this issue: Page 1 Water Meters
Pages 2, 3 and 4 The Odouridder™ Page 5 WSAA product appraisal reports. .
A STORY OF LOCAL INITIATIVE – THE ODOURIDDER™
On pages two, three and four there is an article prepared by Ivan de Souza, the developer of the Odouridder™. It is a very impressive article that describes the development of a product through to its commercial reality and adoption. It demonstrates how someone working within a water agency can develop an innovative idea into commercial viability. Ivan’s initiative plus the obvious encouragement and support that he has received from the Water Corporation is a wonderful example of what can be achieved with the combination of knowledge, experience and opportunity.
NATIONAL CONTROL OF WATER
METERS - WHERE WE ARE.
Laurie Zucco (Sydney Water), reports on the status of Water Meters after the ‘Workshop’ held in Melbourne on Thursday 1 May 2003. (Refer April issue of WSAA Infrastructure News.)
The National Standards Commission (NSC) is a Commonwealth body with legislative responsibility as set out in the National Measurement Act 1960. As part of these responsibilities the NSC has had the Act amended to incorporate mandatory requirements for utility metering.
The amendment was passed in March 1999 providing the NSC with control over water metering (electricity and gas metering as well) Pattern Approval and Verification of meters to a specified standard. The NSC has outlined these specifications in the document titled R49-1 ‘Water Meters Intended for the Metering of Cold Potable Water’. The new Pattern Approval and Verification controls are not a great concern to water utilities as similar controls have been in place and used within Australia for some years.
However, the R 49-1 document also refers to meter accuracy within service. The requirement is that meters ‘in-service’ must be within twice the ‘as new’ meter accuracy criteria. This is a concern to water utilities as meter accuracy is not maintained for long periods after being installed, and if such controls were to be enforced water utilities would need to replace meters early within their economic life and incur major increases in replacement expenditure.
To substantiate the water utilities position for an economic and justifiable replacement criteria, WSAA and its members have been carrying out a number of accuracy flow tests on numerous water meters, and coordinating available water meter accuracy data to build a profile of meter accuracy performance. In addition a number of studies which indicate the water usage patterns of typical consumer households will be used to provide a basis for establishing ‘in-service’ test flow rate criteria.
WSAA and its committee representatives are also involved in rewriting the current Australian Standard AS 3565 to incorporate new NSC flow requirements and an additional document for ‘in-service’ compliance for water meters.
As soon as the meter testing is completed and sufficient data has been obtained, WSAA will be negotiating with the NSC as to the R49-1 ‘in-service’ requirements. The outcome expected is that the NSC will accept the WSAA position that the ‘in-service’ criteria for water meters be based on a management control framework representative of actual water usage and practical water meter performance.
It should also be noted that while the NSC has responsibility for the Pattern Approval and Verification of water meters, ‘in-service’ compliance responsibilities remain with State bodies such as Trade Measurement Victoria (TMV). TMV have already had state legislation passed to control ‘in-service’ compliance of meters and may be in a position later this year to implement controls. There has not been any activity by other state regulators at this stage.
If you need more information email Laurie at [email protected]☻
ODOURIDDERTM Biofiltration Systems By Ivan de Souza
Introduction
The Water Corporation of Western Australia is a statutory corporation responsible for the water supply, sewerage and drainage in the State of Western Australia which has a population of over 1.5 million people. It owns and operates sewerage schemes ranging from the Perth Metropolitan area to more than 250 cities, towns and small communities throughout the state.
The Water Corporation of Western Australia is considered to be the owner of the largest number of vacuum sewerage schemes in the world with over 20 separate schemes.
Most of the vacuum sewerage pump stations were constructed with compost filter beds on the discharge of the vacuum pumps to treat the odorous gasses.
Need
Various methods and processes have been trialled by the Water Corporation in the management of odours, which include activated carbon adsorption, ozone, dispersion vent stacks, soil-filters, compost filter beds and odour-masking agents. Nearly all of these methods had disadvantages, generally relating to difficulties in odour treatment for the large variations in sewage septicity, and including high capital and operational costs.
Compost filter beds have been installed for odour control at nearly all of the Corporation's vacuum sewage pumping stations.
The compost filter beds in use were very basic in design, improperly sized, with inadequate drainage, and with no controls in place to maintain a suitable environment to sustain the microbial activity in the media. With inadequate control over the temperature and moisture content of the filter mass, the relative humidity, crucial to the satisfactory performance of the biofilter, is affected.
These compost beds worked quite effectively for the initial period of 6–12 months, but this was followed by a progressive deterioration of odour removal efficiencies. Other factors affecting removal efficiencies were improper media selection, compaction, acidification and drying out or water logging. Accordingly, performance of the compost filter was adversely affected, resulting in odour complaints from residents in close proximity.
After investigating the failure modes of these odour mitigation systems, a biofiltration system was designed to specifically address the previous deficiencies with a view to using it at the Corporation’s Picton Rd Sewage Vacuum Pumping Station.
In order to obtain optimum system performance and odour removal efficiency, special features were incorporated in its design to control and monitor moisture content and temperature in the biofilter. The careful sizing and design of the enclosures of the biofilter, selection of filter media ingredients and a unique media tray design, ensured that the conditions and environment available were ideal for the growth and long-term survival of the microbes in the media.
The biofiltration system at the Picton Rd VSPS has been in operation since December 1999 without any operational problems or odour emissions. Gas data loggers installed at this site have shown removal efficiencies of hydrogen sulphide to be >99.0%.
An Australian Patent application on the biofiltration system has been obtained and AIRVAC-RSM Ltd, a world leader in vacuum sewerage systems has obtained the marketing licence for the system.
Future vacuum sewerage systems in the Water Corporation will incorporate the Odouridder™ Biofiltration System in the vacuum sewage pumping station design drawings.
The Beachlands Vacuum Sewerage Pumping Station commissioned in June 2002 (see photo on page 4), was the first of the new “breed” of biofiltration systems to treat the odours. The system is built integral with the pump station building, complete with humidifying and temperature controls and with provision for SCADA connection.
Research and Development Project
Due to the very satisfactory performance of the biofiltration system in controlling odours at the Picton Road Vacuum SPS, a proposal was made to the Corporation’s Technology and Research Management Branch for funding a project for the further development and testing of the system. Approval was granted for trials at the Bordeaux Lane Sewage Pumping Station site (see photo on page 4).
This station is adjacent to residential property and the Corporation had received numerous odour complaints from the residents. Average levels of H2S concentrations
in the wet well were 200 ppm and peaking to 750 ppm in the early morning hours.
The OdouridderTM Biofiltration System that was installed at this site is essentially, similar in concept and process design to the one at Picton Rd Vacuum SPS, except that it is modular, constructed of polyethylene, has a separate humidifying/moisture separating unit and is also equipped with continuous H2S monitoring sensors, including fault
alarms.
Description of OdouridderTM
The OdouridderTM is a biological odour treatment system, which utilises biologically–active microbes in the filter media to remove odorous gasses contained in waste air streams.
How does it work?
The Biofiltration System consists of a Humidifying/Moisture-separating Unit and one or more Biofilter stacks. The contaminated air from the wet well or from any odour source is vented into the Humidifying Unit where the humidity and temperature is maintained for optimum metabolic activity of the micro-organisms in the biofilter media.
The Humidifying/Moisture-separating Unit consists of 2 chambers each of them serving a different purpose. The foul air enters the top chamber and bubbles up through the water which is heated and maintained at a set value.
The humidified air leaves the Humidifying Unit and enters a pipe manifold which directs the air to the top of the Biofilter stack and flows downward through the biologically active filter media trays. The odorous compounds in the gas phase transfer to the aqueous phase within the biofilter. The contaminants in the gas stream are absorbed into the liquid film surrounding the particles of the media. The micro-organisms that live in this liquid film oxidise the contaminants utilising the oxygen in the air stream to convert the hydrogen sulphide and other volatile organic compounds into sulphate, water and carbon dioxide.
The deodorised air exits from the bottom of the Biofilter stacks via a manifold into the lower chamber of the Humidifying/Moisture-separating Unit. The water in the treated air is shed in this moisture-separating chamber and drained off to waste. The dry treated air is discharged into the atmosphere through a short stack.
Draeger H2S sensors upstream and downstream of
the biofiltration system continuously measure its odour removal efficiency. Alarms are transmitted to the Call Centre for various failure modes such as power failure, outlet H2S concentrations exceeding 3
ppm, fan failure and heater failure.
Operational Costs and Benefits over other systems
Compared to the activated carbon, ozone and chemical treatment systems in use, the capital and operation costs of the OdouridderTM are considerably lower.
Flexibility of system design allows for a customised approach to each application. Sizing and construction of the system has been simplified by its unique expandable modular design concept. Tough high density polyethylene used in the construction of the enclosures and internal components provide chemical resistance to the acidic conditions generated by the oxidation of the reduced sulphur compounds.
The system is automatic and requires minimal operational input. H2S removal efficiency is consistently greater than 99%.
The specially blended filter media has been optimised for moisture and nutrient levels, low pressure drop, absorptivity and pH control.
Life expectancy of the filter media ranges from 3 to 5 years. Media replacement is made easy and with minimal downtime due to the system’s unique tray design. The expended media is not hazardous and is easily disposed off.
Flexibility of design has been achieved by the system’s expandable modular concept. This allows the system to be designed for various applications and removal efficiency expectations. The biofiltration system has, because of its tiered-tray design, a fairly small footprint thereby reducing the need for expensive real estate, as has been the case with compost filter beds.
A big attraction for water utilities is the use of the OdouridderTM at wastewater treatment plants to reduce
the amount of land required for a buffer around the plant. As population growth puts greater demand on the location of wastewater treatment plants, the cost of the land can become significant. In some cases the sale of buffer land can make the cost of odour treatment insignificant. Contributions from developers can also offset the cost of the odour treatment.
Performance
There are currently 3 OdouridderTM Biofiltration Systems in service in Western Australia and there are 2 more currently under construction.
Extensive testing has been carried out on the OdouridderTM Biofiltration Systems in operational situations to enable the Water Corporation to prove the operational reliability and odour removal capabilities of the device. In operational service it has been demonstrated that the OdouridderTM Biofiltration Systems reduce hydrogen sulphide levels from waste gas streams by greater than 99%
Applications
The OdouridderTM is ideal for treating foul air discharged from vacuum sewage pumping stations. Its use in extraction and treatment of sewer gases from the wetwells of gravity sewerage pump stations has an additional beneficial effect by ventilating and reducing H2S levels in
the gravity system. Extraction and treatment of the highly corrosive gasses in the wet well of the pump station prevents concrete corrosion and foul air emissions into the environment.
The OdouridderTM can be used at wastewater treatment plants to treat odours at its inlet structures and other odour sources.
AIRVAC Engineers quickly recognised that the OdouridderTM had many more applications than just vacuum sewerage. The OdouridderTM also has a number of applications outside the municipal water industry such as:
Intensive farming operations – Pig farming, chicken farming, industrial processing plants and solid waste disposal/recycling plants.
If you need more information email Ivan at: [email protected]☻
Beachlands Vacuum Sewerage Pumping station, Geraldton Biostacks Humidifying unit Vent stack Biostacks Humidifying unit
Moisture separating unit Extraction fan
OdouridderTM Biofiltration System at Bordeaux Lane SPS
Sewer gas inlet Outlet stack
Page 5 of 5
WSAA PRODUCT APPRAISAL REPORTS
The WSAA product appraisal reports have, until recently only been available to WSAA Members and Associate members under restricted publication in the ‘Members only’ section of the WSAA web site. The appraisal holder (The Applicant) is also issued with a copy for marketing purposes and other use as appropriate. All new and previously completed product appraisal reports are being progressively placed in the ‘Bookshop’ section of the WSAA web site for free public access and download. Public availability of appraisal reports is seen as a benefit to appraisal holders, their customers and potential customers.
The WSAA Board has recognised that there are liability risks in the publication of appraisal reports and recent legal advice has recommended specific safeguards in the form of insurance requirements plus ‘disclaimer’ statements to be included in each report. The appraisal “Terms and Conditions” have been revised accordingly along with the “Application Form”. Both are available for review and free download on the WSAA web site (http://www.wsaa.asn.au). For the additional WSAA requirement for insurance details see Clause 5.6 of the Terms and Conditions.
Prior to public web site listing, each existing appraisal report is being updated and revised as necessary. Commencing several months ago appraisal holders are progressively being advised of the required changes and the need to bring each appraisal up to date and submit a new signed application form.
After 5 years there are many appraisals that are in need of technical revision caused by changes to the product or the manufacturing standard or both.
This WSAA initiative is at no cost to the appraisal holder provided there are no changes or reappraisal of the product required caused by product changes or changes to the appraisal criteria (product standard).
The list of appraisal reports on the web site shows the completed appraisal reports that are available for view or download designated with ‘C’. Those that are continuing to be processed are designated with ‘C-Under review’. Where the appraisal holder has declined the revision requirements, their appraisals have been withdrawn and they are no longer listed on the web site.
To view the appraisal reports on the WSAA web site follow the drop down screen listings:
‘Projects’
‘National Codes’
‘Product Appraisals’
‘Reports’
To view or download, click on the desired report to access the report listing in the ‘Bookshop’. Then click on
‘Download’ located near the top right hand corner of the screen to bring up the report.
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ARTICLES OF INTEREST
You are invited to submit articles of interest to Leith Forbes or by fax to 03 9802 1521.☻
