Following on from the successful construction and commissioning of the Coppabella Water Treatment Plant Aurizon Holdings Limited engaged Dowdens Pumping & Water Treatment [Mackay & Brisbane Branches] to deliver a much needed Sewage Treatment Plant (STP) Upgrade at their Coppabella Township, located on the Goonyella Rail Corridor (the world's largest metallurgical coal rail system) - 159 kilometres South West of Mackay, QLD. The Coppabella STP Upgrade project entailed the addition of an Ultra-Filtration (UF) 'Polishing' Plant onto the existing STP. Dowdens new UF 'Polishing' Plant can produce up to 180 kL/day of treated Class A effluent.

The township of Coppabella was primarily designed and built to service the junction of two railway lines (one from Goonyella Coal Mine and one from Saraji Coal Mine) and to provide accommodation to the regions coal mine workers in work depots. The town is wholly owned and operated by Aurizon Holdings Limited and contains: stations, residences, single-quarters, work depots, hotel, a shop, swimming pool, football oval, caravan park, school, ambulance, fire brigade, the recently completed Dowdens whole-of-town Water Treatment Plant and of course the upgraded Sewage Treatment Plant which is now capable of producing 180kL of treated Class A effluent per day for above ground irrigation applications. The local Coppabella Golf Course is one area where this treated effluent is used for irrigation.

After successfully completing various projects for Aurizon Holdings Limited, Dowdens won the tender to provide the process design together with equipment supply, civil construction, installation, commissioning and training for the STP plant operators. The construction phase of the project began with extensive civil works being undertaken to raise the ground level for the new STP components. The pre-existing STP has historically been subject to flooding during heavy rainfall events due to the sites proximity to the local creek. Upon surveying the sites substrate a water table was discovered 1m below ground level.

Working with local Civil Engineers Cardno a substantial foundation was designed / laid to ensure the new buildings, plant components and 4,000 tonne water tank would be stable and remain above the flood plain even during heavy rainfall. Once foundations were laid Dowdens began construction of the 400,000L lined stainless steel water tank, new building to properly house the STP process equipment, an operators office, laboratory facilities and a back-up generator used to power the entire STP in the event of power loss.

After extensive effluent testing and thorough examination of the existing STP process a UF 'Polishing' Plant was designed by Dowdens inhouse Water Treatment Engineering Dept. capable of processing up to 180kL of partially treated sewage effluent per day. The partially treated sewage effluent was rated as Class C and needed to be treated to an acceptable level (Class A) to then be used for above ground irrigation. This treatment process consists of three stages of filtration and sterilisation, including UF. This three-stage process runs as follows:

• Primary treated effluent from the existing STP (Class C quality) is transferred to a 45,000L Glass Media Filtration (GMF) feed tank via duty / stand-by submersible pumps on demand.
• In Stage 1 the clarified effluent from the existing STP process is first dosed with sodium hypochlorite as primary disinfection, to reduce biofouling of the Glass Media. It is then passed through the duty/stand-by Glass Media Filters which reduce particulates, suspended solids and turbidity from the GMF filtrate stream. This ensures no large particles damage the UF membranes in Stage 2.
• In Stage 2 the GMF filtrate is then passed through UF treatment process which incorporates 5% 'cross-flow' to maximise the filtration run-time between back flushes (triggered by high trans-membrane pressure). The systems consists of 8 individual outside-in PVDF membranes which reduce turbidity to less than 1 NTU (Nephelometric Turbidity Units) whilst removing any particles greater than 0.0002mm from the permeate stream. The UF feed is again dosed with sodium hypochlorite to assist with cleaning the UF membranes from biological and organic fouling between the backwash and Chemical Enhanced Back Flush (CEBF) cycles.
• In Stage 3 the UF filtrate is passed through duty/stand-by Activated Carbon Filters (ACF) on demand to reduce colour and odour (by removing aromatic compounds) as a final 'polish' before being fed to the treated effluent tank. The ACF filtrate is then dosed with sodium hypochlorite as a final disinfection of the treated effluent prior to it entering the treated effluent storage tank for dispersal via above ground irrigation systems. Dowdens provided a centralised, custom designed / fabricated, packaged chemical dosing system for this UF 'Polishing' Plant which included a 1000L Chemical Storage tank, a splash-proof racking area housing 5 individual Chemical Dosing pumps - complete with an internal bund and double containment dosing line connections.

When the treated effluent arrives in the 400kL stainless steel tank a recirculation system pumps it through a chlorine analyser and back to the treated effluent tank. The chlorine analyser then controls the residual free chlorine level in the treated water and will start / stop a chemical dosing pump as required to maintain the pre-set residual free chlorine level.

Each of the GMF, UF and ACF processes are periodically backwashed and cleaned, with residual waste being fed to a nearby buffer dam where chlorine is allowed to dissipate. Based on the level in the buffer dam and the level in the treated effluent tank, the water may then be returned to the pump station at the front of the STP for reprocessing.

With a history of successful installations over the past 20 years throughout the Queensland Mining Sector Dowdens Pumping & Water Treatment have the ability to expertly design / manufacture / install and commission specialised pumping and water treatment solutions that are built primarily in-house & onsite to client's specific unique requirements. The Coppabella STP Upgrade project is yet another example of Dowdens unparallelled capability to deliver specialised long-term engineered fluid handling solutions from project inception through to final commissioning / handover.

Dowdens Pumping and Water Treatment designed and built the longwall boost pump station utilising dual variable speed pumps to enable the station to cater for varying duties as the underground workings progress further away from the station.

Anglo American's Moranbah North coal mine began operation in 1998 and currently supplies 4.5m tonne annually of high fluidity premium hard coking coal mainly for export to iron and steel manufacturers in Japan, Korea and Taiwan.

• All wiring / electrical installation & commissioning on these pump stations was undertaken by Major Electrical Pty Ltd
• KROHNE flow meter
• Pump station utilises four pressure transducers to feed real time pumping data to the computer control
• Two vertical stage pumps directly coupled to two 45kW motors
• As the booster pump station was dealing with high pressures all piping and flanges have a 3,000kPa rating
• Pump station fitted with QDS (Quick Detachment System) lift points - allowing the station to be transferable via the underground Line Eimco
• Touch screen interface enables underground miners access to real time amperage, bearing temperature and flow rate data
• The unit operates via a PLC (Programmable Logic Controller) and SCADA (Supervisory Control and Data Acquisition) system meaning it can be remotely operated from the mine control room on the surface, or underground via the unit's electronic controls

Total Water Volume Transfer: 30L/sec @ 80m head (currently)

Peabody Energy Australia have engaged Dowdens Pumping & Water Treatment's [Mackay] Engineering Department & Fabrication Workshop to deliver a Specialised Pontoon Pumping System for use at their Moorvale Coal Mine, located 156 kilometres South West of Mackay, QLD. This project presented a number of challenges for the Dowdens Mackay engineering and fabrication staff, including but not limited to an extremely tight delivery timeline of only 8 weeks!

Peabody Energy's Moorvale Mine is an open-cut coal mine that produces low-volatile pulverized coal injection (PCI) coal, coking coal and thermal coal for export markets. The Moorvale Coal Mine is particularly challenging for its operators due to the coal seam being quite narrow with a number of fault lines. This requires excavators often having to work in confined areas. The three piles that make up the Moorvale coal seams are mined independently of each other.

Dowdens Specialised Pontoon Pumping System was needed to provide Peabody Energy more reliable access to good quality Raw Water from an on-site dam. This raw dam water was then to be pumped directly to the onsite Coal Handling & Preparation Plant (CHPP). The existing supply water was limited and of poor quality. Dowdens new pontoon pumping system allowed for an increased volume of water to be pumped from a dam containing higher quality raw water. Subsequently the Specialised Pontoon Pumping System that Dowdens supplied has helped facilitate an improvement in the CHPP's daily operations.

This project required both Dowdens Engineering Dept. & Fabrication Teams to deliver an innovative solution not previously attempted in-house. It was the first time Dowdens had manufactured 12m length gangways or a pontoon with a total weight of over 6 tonne. The total pontoon weight includes all steel work, flooring, pumps, piping etc. and is displaced using HDPE (high density polyethylene) Floats. The longest gangway Dowdens had supplied previously measured 8m in length, with the largest pontoon previously fabricated weighing in at 4.5 tonnes.

The new system meant Dowdens existing in-house designs had to be modified / improved with new floats being selected in order to safely carry the increased platform weight. Additional weight saving measures were implemented by Dowdens Engineers such as the use of light weight / high strength aluminium mesh flooring.

The timeline to design this pontoon pumping solution, manufacture the components and have them delivered to site was extremely tight. Engineering - Concept Design - Drawings & In-House Fabrication of the unique Pontoon Pumping System was completed & delivered to Moorvale Mine within their specified 8 week time frame!

No other pumping / manufacturing / engineering firm in Queensland are able to deliver such an all-encompassing product solution within the above mentioned time-frame.

Dowdens design philosophy for this project was: Fast Turnaround - Cost Effectiveness - Ease of Installation - Simple Plant Operation - Plant Reliability & Reduced Maintenance.

Key Project Features:

• 2 x 12m long gangways - with one being suspended and one floating on the dams surface
• Gangways Design, Fabrication, Fitout & Supply included all necessary concrete mooring blocks, lights, cables & trays
• 6m x 3.3m floating pontoon - weighing over 6 tonnes
• Pontoons Design, Fabrication, Fitout & Supply included lights, suction and discharge pipework, priming system, cables & trays

BHP Billiton Mitsubishi Alliance (BMA) engaged Dowdens Pumping & Water Treatment [Brisbane] to design, manufacture, install & commission a 200kL / day Sewage Treatment Plant (STP) which included three pump stations and a specialised central control room at their Saraji Coal Mine, located 60km southeast of Moranbah and 200km southwest of Mackay in the Bowen Basin, Central Queensland.

Saraji Coal Mine has coal reserves amounting to 648 million tonnes of coking coal, one of the largest coal reserves in Asia and the world. The mine has an annual production capacity of 5 million tonnes, utilising open-cast extraction methods with a total of 11 coal seams.

Saraji Coal Mine required a new STP due to the existing onsite plant failing to meet release limits and becoming unsafe to operate. Dowdens Brisbane designed a new STP that incorporated the innovative MIRACELL™ Rotating Biological Contactors (RBC). RBC technology is a type of sewage treatment process in which disks that are connected to a shaft are rotated at a very low speed (3.7 rpm) by means of a motor which is equipped with a reduction gear. The MIRACELL™ RBCs are designed such that 40% of the disks remain in the wastewater.

As the discs rotate contact with the wastewater causes turbulence and consequently aeration. As a result of this repetitive process, organisms accumulate on the discs. The organisms receive the necessary oxygen from the air during the rotation of the discs and consume the pollutants existing in the wastewater, converting them to carbon dioxide and water in a totally natural way. The treated water discharged from any MIRACELL™ STP is guaranteed to meet the most stringent discharge standards and may be used for dust suppression, irrigation or directly discharged to a waterway subject to Environmental Authority approval.

MIRACELL™ Sewage Treatment Plants are fully automatic, utilising modular designed RBCs specifically designed for sewage treatment applications in capacities ranging from 50 to 20,000 Equivalent People (treatment of between 10m³ up to 4000m³ per day). Representing the ultimate in sewage treatment systems, a MIRACELL™ STP consumes as little as one fifth of the electricity and requires as little as one third of the space of its competitors based on the activated sludge technology.

Dowdens Pumping & Water Treatment are proud to hold Australia-wide exclusive distribution rights for MIRACELL™ STPs - these systems are most preferred by customers who clearly understand the economic value in purchasing an expertly designed and professionally built system. Offering a comprehensive range of innovative MIRACELL™ STPs, Dowdens provide an all-in-one service approach to each project. From project inception through to final commissioning, our team of industry trained engineers, draftsmen, project managers, sales staff and tradespeople including electricians, fitters, polywelders and plumbers will have you covered!

Dowdens Pumping & Water Treatment [Brisbane] were successful in the initial tendering process as we could deliver a complete turnkey Sewage Treatment Plant solution within the limited project budget, whilst also meeting all of BMA's specifications.

The standalone Sewage Treatment Plant Dowdens Brisbane supplied BMA provided an expertly-designed system that allowed them to meet their regulatory requirements, whilst providing a reliable, easily operated and maintained system. The new Saraji MIRACELL™ STP needed to accommodate the total mine site workforce of 645 Equivalent Persons (EP). Dowdens have designed the Saraji MIRACELL™ STP to treat up to five times the Average Dry Weather Flow rate of 40 kL/day - meaning the STP has the capacity to easily process and treat up to 200kL/day.

The Saraji MIRACELL™ STP and three fibreglass pump stations have been designed to capture and treat all waste influent (both Sewage & Grey Water) from the entire mine site and deliver it to the STP for processing. The system's design had to not only deliver the desired treated effluent quality but also incorporate strict safety requirements while adhering to the Queensland Government's Department of Environment and Heritage Protection stringent environmental conditions.

The Saraji MIRACELL™ STP includes a pH correction system to allow for pH correction. The pH correction dosing system comprises a pH correction chemical storage tank and a dosing pump. An Electromagnetic flow meter installed on the inlet of the chlorine contact tank automatically adjusts the chemical dosing rate based on the incoming treated effluent volume. This ensures the pH on the outlet of chlorine contact tank is always within the range of pH 6-9.

The Saraji MIRACELL™ STP is also equipped with a remote monitoring feature that enables the Saraji Mine operators to check the status of the STP from anywhere in Australia via portable devices such as smartphones or tablets.

Dowdens Pumping & Water Treatment [Brisbane] design philosophy for this project was: Cost Effectiveness - Current Best Practice - Ease of Installation - Simple Plant Operation - Plant Reliability & Reduced Maintenance.

Beginning in June, running through to October 2015 the Saraji Mine MIRACELL™ STP was delivered on time and within budget. Extensive onsite works were undertaken by Dowdens Pumping & Water Treatment to enable the new system to be properly housed and connected to existing site, power and pipework infrastructure. The STPs construction works involved (but was not limited to) civil, electrical, mechanical, hydraulic and structural works utilising Dowdens Infield Service / Installation Crew, Supervisors, Engineers and Project Management.

Key Project Milestones & System Components are listed below:

• Concrete foundations and bund
• 3x Fibreglass Pump Stations Installed (two in ground & one above ground)
• 1x 47kL Equalisation Tank
• 2x 22kL Primary Settling Tanks
• 4x MIRACELL™ Rotating Biological Contactors (RBC)
• 1x MIRACELL™ Lamella Plate Clarifier
• 1x Recycled Activated Sludge System
• 1x Chlorine Contact Tank
• Chlorine Dosing Equipment
• pH Correction Dosing Equipment

• 1x Central Control Room
• 1x Control Panel including Human Machine Interface (HMI) Touch Screen
• Safety Shower & Hazchem Storage Equipment
• Installation of roof over STP
• Construction of onsite car park
• External Lighting
• Security Fencing
• Earth bund around the perimeter of STP
• Manufacture of Platforms & Staircases

BHP Billiton Mitsubishi Alliance (BMA) have engaged Dowdens Pumping & Water Treatment's Mackay Branch to deliver a specialised Modular Underground Dewatering System at their Broadmeadow Coal Mine, located approximately 200km South West of Mackay, QLD.

The Broadmeadow Underground Coal Mine is a 'Top Coal Cave Longwall Punch' mine located approximately 30km from Moranbah. Located on BMA's Goonyella open cut mine lease, the Broadmeadow Mine was established in late 2003 and feature's BMA's first application of punch longwall mining - a highly efficient underground technique utilising an existing open cut pit for longwall panel access. Broadmeadow Mine delivered a number of synergies between BMA's underground and open cut operations, including utilisation of the existing Goonyella coal preparation plant capacity, increased flexibility to respond to market demand, improved reliability of supply for customers and optimisation of product quality through selective blending.

The Modular Underground Dewatering System (MUDS) was designed / manufactured and installed by Dowdens Mackay to optimise further development of BMA's Broadmeadow mining operations by improving on-site dewatering efficiencies. The MUDS has been utilised in developing Broadmeadow panels 12 & 13, and will help to advance mine site progression for the entire life of operations. The main objective of this project was to provide a unique, custom built air / electric pump system to improve Broadmeadow's dewatering efficiency. This was achieved through the automation of pumping systems supplied and lowering any ongoing maintenance requirements - thereby saving site operator input, lowering air / power consumption and reducing the need for BMA to further invest in dewatering pump systems.

Dowdens were engaged during the concept phase of this project to provide input and engineering advice to help BMA overcome the many operational challenges this site presented. With intimate product knowledge and via extensive direct consultation 2 unique transportable Quick Docking System (QDS) Fish Tank Dewatering POD designs were developed. Capable of operating under 1,000V power, these modular POD systems required the ability to remain operational during regular power outages, utilising the limited underground supply of compressed air. Each pump station needed considerable storage / retention capabilities (5,000L per POD) and the capacity to operate seamlessly 'in-sequence' thereby delivering zero overflows onto roadways even during loss of underground power.

The composition of the water derived from the mine's development process posed its own transportation challenges with a high water content ratio of rock, coal, trash and coal fines. A solids management system consisting of various sieves, hoppers and tank agitation components was developed and tested to ensure the coal fines and inflow management system was capable of continuous operation, whilst also delivering simplified maintenance and cleaning procedures.

The coal fines and inflow management system was designed with the ability to:

• Retrofit to existing POD systems recovered from the Crinum underground coal mine
• Bolster the developing site dewatering fleet - with continuity of all pumps, instrumentation & control equipment used.

With the negotiations finalised, Dowdens proposed the fabrication of 2 Teams of 4x Dewatering PODs. Each Team is led by the newly designed 5m³ EXD QDS transportable roadway POD. 3x additional specially modified 4m³ Elliptical PODs (a combination of EXD & IP66 rated) are then positioned at strategic intervals along the panel as main gate development advances.

Dowdens Pumping & Water Treatment was successful in BMA's tendering process due to:

• Vast in-house engineering, drafting/design, fabrication, servicing capabilities & proven competencies
• Over 20 years' experience designing & producing specialised underground dewatering equipment
• The proximity of Dowdens head office [Mackay] & ongoing presence in the region
• Providing a competitively priced solution to the clients unique challenges
• High level of detail provided in the preliminary engineering proposal

After a successful tendering process Dowdens team of engineers and draftsmen immediately began analysing the recovered Crinum mine 4m³ POD design. After much consideration, a plan was established to incorporate all new specifications and functionality required whilst retaining as much of the existing structure as possible, saving both fabrication time and money. This design was carried over to the new generation 4m³ Elliptical PODs.

The Narrow Gauge 5m³ Lead POD had to utilise every inch of its restricted underground foot print to facilitate the 5,000L capacity and extra-large solids screening hopper. All work access steps and ladders were designed to be stowed away to avoid contact by passing machinery. All equipment was to be readily accessible to operators, even while positioned hard against the roadway rib. The complete set of design drawings were completed within 5 days and construction began immediately ensuring delivery was made within BMA's tight project deadlines.

Specially equipped 1,000V electric motors were incorporated in the build to operate custom made hard-metal centrifugal pumps - primarily selected for water transfer between PODs operating 'in-sequence'. The Cast Iron WILDEN T15 Air Operated Double Diaphragm Pump was selected to serve as the auxiliary system for its robustness and relatively small weight-to-flow ratio. The lower weight and lower capital cost of the T15 allowed two pumps to be incorporated into each pump station to serve in duty / standby, or duty / assist mode if required.

A pneumatic control system provides seamless switching between air and electric pumping modes. Non-powered level controls allow maximum tank differential between the air pumps 'on & off' functions saving air consumption. Potential overflows are prevented by a pneumatically operated, inflow regulating valve. Each of the POD inflow manifolds are equipped with 4 auxiliary 50mm pump inputs to integrate localised pumping to the 'outbye' system. Custom built electrical control panels incorporate all EX'd field devices providing temperature, pressure, flow & fault communications via a PLC to the site Citect system. Area lighting and visual pump status indicator lights can be positioned remotely ensuring clear viewing from the mines underground roadways.

Dowdens Pumping & Water Treatment design philosophy for this project was: Cost Effectiveness - Current Best Practice - Ease of Installation - Simple & Effective Plant Operation - Plant Reliability & Reduced Ongoing Maintenance.

Modular Underground Dewatering System's Key Components are listed below:

• Creation of a completely new Custom Narrow Gauge POD Design to suit clients space restrictions near Development Miner
• Supply of 2x teams of 4x PODs, 1 team for each main-gate under development (each team consisting of a special Narrow Gauge 5m³ Lead POD & 3x Modified 4m³ Elliptical PODs)
• Automatic Duty / Standby Cast Iron WILDEN T15 Air Operated Double Diaphragm Pump Backup with full starting / stopping control to minimise air consumption
• Automatic Shutdown of incoming water on High Tank Level (preventing overflows)

• Two levels of screening for incoming water to eliminate pump blockages
• Colour Coded POD visual lighting to indicate whether POD is healthy ('green') or in fault ('orange')
• System designed with site operators needs in mind - No entry to tank required to maintain field devices
• Supply of specially fabricated stainless steel canopies for Pump Starter (top & back) to protect against physical damage
• Provision of DN50 Camlock inlets - providing a readily accessible connection point for incoming water

Wilmar Sugar Australia Limited employed Dowdens Pumping & Water Treatment [Mackay] to deliver a broad acre irrigation system at their Gibson Creek sugarcane farm. Wilmar Sugar Australia Limited is Australia's largest raw sugar producer and one of the top 10 producers in the world.

The Gibson Creek sugarcane farm has a total area of 2,000ha, with works completed by Dowdens to date delivering irrigation to over 750ha of sugarcane - this project is still ongoing with the aim to irrigate the full 2,000ha upon completion. The broad acre irrigation system was designed, sourced, installed and commissioned by the Dowdens Pumping & Water Treatment Agricultural Sales Team, which has over 125 years combined agriculture irrigation experience.

The system is required to pump water stored in Wilmar's onsite dam (which when completed will hold a total of 2,000ML) to various irrigation devices watering 2,000ha of sugarcane.

To date the project has seen the team at Dowdens construct, install and commission six Valley Center Pivot Irrigators, with spans ranging from 520m down to 410m, and three hard hose poly line traveling irrigators.

Water for the irrigation system (sourced from Wilmar's 2,000ML onsite dam) required Dowdens to lay an extensive network of poly and PVC mains pipework ranging from 500mm to 150mm in diameter. In total over 12kms of mains pipe has been laid so far.

The entire system is gravity fed from the large onsite dam with a 6-cylinder John Deere diesel engine centrifugal pump feeding the six pivots, and three IVECO-Caprari multistage diesel booster pumps [pictured below] kicking in to raise mains pressure when water is required at the three hard hose poly line travelling irrigators.

The entire project was overseen and managed by Glenn Agnew from the Dowdens Pumping & Water Treatment [Mackay] Agricultural Sales Team.

Key Project Features:

• Six Valley Center Pivot Irrigators installed with spans ranging from 520m to 410m
• The Valley Center Pivots were fitted with auto-start generator sets - eliminating the need for farmers to travel to each individual Center Pivot to activate once feed pumps are on
• To date over 12kms of mains poly and PVC pipe has been trenched, welded and commissioned
• Dowdens sourced, delivered and commissioned three hard hose poly line traveling irrigators [2x Idrofoglia & 1x Trailco]
• 1x 6-cylinder John Deere diesel engine centrifugal pump feeds the six Valley Center Pivot Irrigators
• 3x IVECO-Caprari multistage diesel booster pumps transfer water to the three hard hose poly line traveling irrigators when required