Tumbarumba 3ML/d DAFF Water Treatment Plant

Transcription

1 Tumbarumba 3ML/d DAFF Water Treatment Plant Final Progress Report June 2012

2 FOREWORD This final report for the Tumbarumba 3ML/d DAFF Water Treatment Plant is prepared to fulfil the requirement of Australian Government s funding deed requirement. The report presents the detail of project activities from concept to completion. This is a very successful project, in terms of resources utilization, management and benefits to community. It has made possible the production of drinking water to meet the project treated water quality requirements and relevant parameters of Australian Drinking Water Guidelines on continuous basis. Prepared by: Reviewed & Approved by: Laxmi Pandey (Water & Wastewater Engineer) Alan Lawrance (Director Engineering Services) Issue Date: Draft, 31 June 2012 Final, 16 July 2012

3 TABLE OF CONTENTS INTRODUCTION... 1 BACKGROUND... 1 PROJECT OBJECTIVE... 1 SCHEME CONCEPT... 2 DESIGN AND CONSTRUCTION OF A 3ML/D DAFF WATER TREATMENT PLANT... 3 PROJECT FUNDING... 4 PROJECT MANAGEMENT... 4 WTP PROCESS... 4 ENVIRONMENT... 7 CONCLUSION... 7 SNAPSHOT OF ACTIVITIES... 8 REFERENCE... 10

4 Introduction Background Tumbarumba Shire Council is situated on the western side of the Snowy Mountains in New South Wales. The original Tumbarumba water supply consisting of chlorination treatment only was built in around The quality of the water supplied to the town was very poor and didn t meet the Australian Drinking Water Guidelines (ADWG). In 2009, Tumbarumba Shire Council (TSC) with the guidance of the NSW Office of Water (NOW) resolved to build a 3 ML/d DAFF Water Treatment Plant on an old disused quarry site adjacent to the existing 68 ML Tumbarumba Reservoir. This decision was made to ensure that the quality of water supplied to the town would meet ADW Guidelines on a continuous basis. The Australian Government generously provided $2 million under the Water for the Future initiative through the Water Smart Australia program. The NSW Government also provided a subsidy of $ 0.73 million under the NSW Country Town Water Supply and Sewerage Program. The remainder of the funds required for the project, $1M, were provided by Council itself. With these large contributions by both the Australian Government and the NSW Government the project commenced. It consisted of the construction of a new modern state of the art water filtration plant and associated works with the capacity to provide a safe, secure and reliable water supply for the Tumbarumba community. TSC engaged NSW Public Works to prepare a concept report and tender documents to establish the criteria for the proposed new water treatment plant and to provide advice to Council in the evaluation of tenders. Tenders were called and the contract for the design and construction of a 3ML/d Water Treatment Plant and a large concrete 2 ML Clear Water Tank and associated works was awarded to Aquatec Maxcon in The project suffered a delayed start due to inclement weather conditions. During the course of the contract the local area experienced two Declared Natural Disaster storm events and extended periods of wet weather that have hindered progression of the project. However regardless of this, the project was successfully completed within the time frame and within the allocated budget. Project Objective The main objectives of the project were to; i. Increase the available water supply for the Tumbarumba Township. This was achieved by installing a 3ML per day Dissolved Air Flotation Filtration System Water Treatment facility. In addition, Council has constructed a new 2ML reinforced concrete Clear Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 1

5 Water Tank for storage of town water. Under the previous system, the amount of water that could be supplied to the town was limited, not only by the quantity of available water from the principal sources, the Burra Creek but also from the poor quality of the water from the secondary source, Tumbarumba Creek. The new water treatment plant allows water of almost any quality to be processed to the full extent of the licence, thus increasing the quantity that can be supplied from the Tumbarumba Creek. This has greatly increased the amount of water that can be filtered with the new plant. ii. Ensure that water treatment from the poorer quality source of Tumbarumba Creek can be used to supplement the current service, Burra Creek thus helping to secure the future. The new facility is able to treat water of very poor quality and still satisfy Australian Drinking Water Guidelines thus enabling a much greater amount of the water from the poorer quality Tumbarumba Creek source to be processed. In summary, upon completion of the project, both of these important objectives had been satisfied. Scheme Concept For many decades, the residents of Tumbarumba township have suffered from the poor quality of its water and the limitations of its water supply. The residents of Tumberumba underwent considerable hardship during the severe water restrictions imposed to mitigate the impact of depleted water sources during the drought conditions between 2001 and The socio economic impacts of this difficult period affected most aspects of daily life and business activity in the town. Council commissioned a number of reports looking at all aspects of the local water cycle to identify opportunities for improving the quality and quantity of water supply. In 2009, Council resolved to build a new water treatment facility on a site adjacent to the existing Tumbarumba Reservoir. Council engaged NSW Public Works to prepare a concept report to establish the design criteria for the proposed new water treatment plant and to draw up tender documents. It was decided that the source water system would remain the same as in the existing system. Raw water from the pristine Burra Creek and the Tumbarumba Creek is piped to the 68 ML Tumbarumba Reservoir located in Power Street, Tumbarumba. It was planned that the new water treatment plant would be designed to produce a net throughput of 3ML/d based on 22 hours of operation per day. The required annual treated water production would be 300ML. Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 2

6 It was originally proposed to convert the existing balance tank to a raw water pumping station. Raw water from the balance tank was to be pumped to the new WTP. This arrangement was amended and provision was made for direct pumping from the 68 ML reservoir directly to the new 3 ML/d plant. Filtered water is now disinfected and collected in the new 2 ML clear water tank (CWT) located beside the new water treatment plant. Treated water from the Clearwater tank then gravitates to the consumers through the existing gravity main downstream. This is far more efficient and the town benefits from the additional pressure head provided by the Clearwater tank located near the Water Treatment Plant. Backwash wastewater and sludge generated in the WTP are treated in two new sludge lagoons and the supernatant from the lagoons is recycled back to the Tumbarumba reservoir. Contract for the Design and Construction of a 3ML/d DAFF Water Treatment Plant In 2010, the contract for the design and construction of a 3 ML/d DAFF Water Treatment Plant Project, Contract No 02/2010 was awarded to Aquatec Maxcon Pty Ltd. The Contract Sum was $3,410, (excl GST). The project start date was 7 th May During the early stages of the project, changes to the proposed order of work were necessitated by the adverse weather conditions during winter and the corresponding Extensions of Time were granted to the date of Practical Completion. The design had been an iterative review process from the beginning involving the contractor, TSC, NSW Office of Water and NSW Public Works resulting in a During the course of the project, a number of variations to the contract were included in the design that have definitely enhanced the new water treatment plant. These included the provision for flow dosing of chemicals instead of fixed dosing, relocation of the clear water tank to a better location, inclusion of a SCADA system, containment of the plant in a single building instead of three buildings, a new chlorination facility and other improvements. The end result is a very efficient, state of the art, safe, operator friendly plant that will greatly benefit the people of Tumbarumba Shire. The actual construction cost including the variations from the original design was $3,719, (excl GST). The project was completed on 8 th November An Opening Ceremony was held on... It was attended by a number of State and Federal Members and residents of Tumbarumba. The new plant was opened by Ms Ursula Stevens, Senator for NSW. Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 3

7 Project Funding Without the assistance of the Australian Government, the project could not have succeeded. The Australian Government provided $2 million under Water for the Future through the Water Smart Australia program. The NSW Government also contributed providing a subsidy of $734K under the NSW Country Town Water Supply and Sewerage Program at the rate of 45.5 per cent of the eligible costs in excess of the $2 million that was funded by the Australian Government. The remaining funds for the project were provided by Tumbarumba Shire. The project has been successfully completed at an all up final cost including initial investigations and Council management costs of $4,070, (excluding GST). The project was completed on time and within the three year timeframe set in the Minister s offer. The project was managed by Tumbarumba Shire Council. All of the Milestones set in the Funding Agreement by the Australian Government were satisfied. Project Management Council provided its own project and construction management services, and sought expert advice, as required. The NSW Office of Water was very helpful and has provided technical assistance to Council staff to manage and successfully complete this project. Also advice from the NSW Department of Finance and Services (Public Works) staff greatly assisted in the project. The Contractor, Aquatec Maxcon are commended for excellent project management. Their staff worked very closely with Council Management staff on the project ensuring quality workmanship and timely completion of milestones. Council s own Water Committee played a very effective role providing direction and guidance during the project period. This has proven to be a very successful, well managed project, completed within the time and budget without any compromise in quality, regulatory, environmental or safety requirements. WTP Process The new Tumbarumba Water Treatment Plant treats water from the existing 68 ML Tumbarumba Reservoir. Provision has also been made to feed raw water directly from the Burra Creek gravity main line to the plant when required. Under normal operating conditions, the Burra Creek and Tumbarumba Creek lines feed directly to the reservoir, which is monitored by a level transmitter. When the level is within limits, the raw water is pumped via self priming centrifugal pumps (duty / standby) via DN200 piping to each of the two DAFF tanks. The line has a magflow meter installed, downstream of which soda ash and alum are dosed. The soda ash is dosed for ph adjustment, whilst the alum is dosed to improve flocculation formation. The two DAFF tanks are located parallel to each other within the main building and connected by a platform. Each of the two stainless steel DAFF tanks has an upstream flocculator section which includes a two stage flocculation process where slow rotating vertical stainless steel shaft paddles provide agitation of the coagulated water to promote agglomeration of particles in order to form large flocculations. Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 4

8 The sludge flotation system removes the majority of flocculated particles from the coagulated water by floating them to the surface to form a sludge blanket, which is removed intermittently by a mechanical skimmer mounted at the downstream end of the filtration section. The treated water gravitates through the media with the solids within the treated water being trapped by the sand and gravel filter material. The filtered water is collected via 1672 polypropylene filter nozzles with strainers which are bolted through a series of plenum flooring panels which are supported 750mm above the filter (plenum) floor. The filter strainers are pitched on a 133 x 136 rectangular grid. They are designed to take bi directional flows (filtrate, backwash and scour air). During the backwash cycle, there is an air scour operation, which involves sourcing air from the blower. The air scour system agitates the layered filter media and dislodges adhered solids without excessive abrasion and attrition of the filter media. Filtered water from the two DAFF filter sections are discharged via the common DN200 underground pipe through the pump station wall into a vertical bell mouth overflow. There are two (duty/standby) submersible centrifugal filtered water pumps which pump the water to the clear water tank via DN150 piping. The delivery piping includes a magflow meter, together with a flow switch. Downstream of the flowmeter are three dosing lances, one for chlorine, one for soda ash and one for sodium fluoride. The clear water tank is a covered concrete tank of dia. 20.5m and 2ML capacity. It is complete with a 1500 wide circular concrete walkway at the bottom and an external ladder to a top platform with an access hatch. The water level in the clear water tank is monitored by transmitter and high high level switch. Alum Dosing System: The proprietary (Grundfos /Alldos) alum storage and dosing system is installed in the bunded storage area in the S W corner of the main building. It is used as a primary coagulant which is dosed into the injection point in the DN200 raw water pump delivery line to the DAFF units to coagulate suspended colloidal matter in the feed water. The pumps are flow paced with the inlet flowmeter, with an operator adjustable dosage rate set via the SCADA. Soda Ash Dosing System: The proprietary (Grundfos/Alldos) soda ash unloading, batching and dosing system is installed in the bunded storage area next to the alum bund at the southern end of the main building. It is used for pre and post ph correction of the conditioned raw water and filtered water. It is dosed into the injection points in the DN200 raw water pump delivery line to the DAFF units, and the DN150 filtered water pump delivery line. Chlorine Dosing System: The proprietary Grundfos gas chlorine system includes a shed for protection of the equipment, which is located to the north of the clear water tank. The chlorine gas is dissolved into a water solution and dosed via an injection point into the DN150 filtered water pipeline upstream of the clear water tank. The dosage is maintained via the chlorine residual as monitored by AE3407 as set by the operator via the SCADA, and either regulated to suit WTP flow rate or flow paced from the filtered water flowmeter. Chlorine dosing is required as a precondition for the operation of the whole plant. Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 5

9 Fluoridation System: The proprietary (Prominent) fluoridation preparation and dosing package is installed in a dedicated room at the S E corner of the main building adjacent to the soda ash chemical area. The chemical is dosed via an injection point into the DN150 filtered water pipeline upstream of the clear water tank and is flow paced from the magflow signal. Sludge Lagoons: Two sludge lagoons have been excavated, with a 3:1 batter each has a working area at the top water level of 800m2. Each lagoon has been sized to contain one year s sludge production sourced from DAFF 1 & 2 backwash piping, which also contains the related skimmed float. The lagoons have been designed for up to 1,000mm settled sludge layer, 500mm water depth and 500mm freeboard. When one lagoon is receiving product, the other lagoon is in the drying mode. Compressed Air System: There are two duty/standby rotary screw type air compressors installed in the machinery room. Each compressor is a proprietary package which includes an oil filter and cooler, an oil/air separator, an air receiver, a dryer and a moisture separator. Electrical and Controls: The augmented plant includes a main switchboard incorporating controls for the clear water pumps, together with a plant motor control centre (MCC). Additionally, the original PLC and control panel had been replaced with a new Allen Bradley PLC hardware located in a new MCC to control the integrated plant. A new programmed PC based SCADA interface comprising a PC located in the Main control room with Citect software, which has been configured to depict the augmented WTP. General: The control system for the plant is designed to be reliable and simple to operate. It enables the production of drinking water to meet the project treated water quality requirements and relevant parameters of Australian Drinking Water Guidelines. The PLC controls all the operations of the Water Treatment Plant. The PLC processes and logs all digital and analogue outputs and operates all sequencing and PID control functions. In addition to monitoring the current status of all plant items and instrumentation output readings, the operator can adjust operational parameters, check and reset alarms, and review historical trends of all instrumentation outputs. The PLC system is connected to a Supervisory Control and Data Acquisition (SCADA) system, providing plant status and alarm signals, both at the plant and remotely. The plant can be controlled remotely using Remote Access Software. This is installed on the plant computer, the duty operator s laptop computer, and the main office computer. Remote Access Software, allows a remote party to dial the plant computer s modem line and assume control of this machine. It is then possible to log on to Citect and run the program in an identical manner to local control. All operator adjustable parameters and features can be accessed in this mode, as can all other programs and features on the plant computer. Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 6

10 The water treatment plant operates in full automatic mode with all necessary alarms on most items of plant, including pumps, drives, systems and water quality monitoring instrumentation to ensure continuous plant operation. Alarms alert operational staff to abnormal conditions that may result in performance outside the specified requirements, danger to plant and / or personnel, failure of equipment, and system faults. Environment The site for the Tumbarumba Water Treatment plant was located on Tumbarumba Shire Council land at the site of a former disused quarry on Power Road Tumbarumba approximately 500m north of Tumbarumba Township. The site is adjacent to the existing 68ML Tumbarumba Reservoir. The Project Review of Environmental Factors (REF) report was prepared by ARL Consulting. There were very minimal environmental impacts of construction and operational activities. However, all practical efforts were undertaken to minimise the noise emission, air/dust pollution, and the priority was to protect the environment from any unanticipated consequences during the construction activities. Tumbarumba Shire Council had conducted a community consultation program to gauge the community s response to the introduction of fluoridation to the Tumbarumba Shire Council s reticulated town water supply. Initially there were a number of objections to the introduction of fluoridation of the water supply system however Council resolved to install fluoridation in accordance with legislation. Since the installation of fluoridation in the town s water supply there have been no objections from the community. Conclusion The operation of new Water Treatment Plant in Tumbarumba provided the town of Tumbarumba with drinking water of a very high standard that satisfies treated water quality requirements and relevant parameters of Australian Drinking Water Guidelines on continuous basis. It has opened the opportunity to use any available raw water resources now and in the future even from the poorer quality sources such as Tumbarumba Creek and the underground bores to meet the town demand without compromising quality of supplied water to the community. The large contribution by both the Australian Government and the NSW Government towards this project has been greatly appreciated by Tumbarumba Shire Council and the community of Tumbarumba without who s financial assistance this project could not have taken place. Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 7

11 Snapshot of Activities WTP Construction Site Official Inauguration of WTP on September 2010 by Tumbarumba Shire Council s Mayor Ian Chaffey Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 8

12 On Tuesday, 24 January 2012 Tumbarumba WTP was officially opened by Senator the Honourable Ursula Stephens, senator for NSW. Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 9

13 WTP tour provided to Tumbarumba Community on 12 February 2012 Reference A copy of this report is also available in the Council Website Enquiries: Alan Lawrance P: (02) E: mail@tumbashire.nsw.gov.au Tumbarumba 3ML/d DAFF Water Treatment Plant Final Report Page 10