Environment Protection Authority v. Sydney Water Corporation [1998] NSWLEC 144

2. The licence was issued in respect of North Head Sewage Treatment Plant at North Head and was in force between 1 July 1994 and 1 July 1995.

The Factual Circumstance relied upon by the Prosecutor

3. On 7 March 1995 the plant flooded. At about 3.00am in the morning it appears that a possum entered the Warringah Electricity Bulk Substation as a consequence of which there was widespread electrical power failure across the northern beaches peninsular area and all mains power to the sewage treatment plant ceased.

4. In essence, as Mr Glissan QC outlined in opening for the prosecutor, the allegation is that owing to the power failure at a time when there was wet weather flow of sewage into the plant, certain penstocks, which are gates that control the flow of sewage through the plant, could not be opened so that the sewage could not bypass the plant and go directly to the cliff face for the duration of the power failure.

5. Penstocks known as the bypass penstocks were closed thereby preventing the release of sewage to the cliff face. The back up of sewage, which continued to flow into the plant, flowed through the screening chamber into the pump suction channel where it overtopped a pump suction channel bypass penstock and then entered the raw sewage pump chamber through an unsealed pump which had been dismantled for maintenance purposes.

6. The prosecution alleges that, in a properly maintained plant, either the outlet channel penstocks would have been open to release the sewage, or the bypass channel penstocks would have been open to release the sewage and a cliff face discharge would have begun, preventing inundation of the plant.

7. On this particular night, the bypass penstocks could not be opened. There was a period of time in which critical operations needed to be undertaken. If the plant had been properly maintained, they could have been undertaken and the problems avoided. The pump suction channel bypass penstock could have been higher, or some blocking device used to prevent the overflow of sewage into the raw sewage pump chamber. Furthermore, the bypass penstocks should have been in a condition where they could be opened.

8. Instead of a cliff face discharge taking place during the ninety one minutes of power failure, the discharge continued over fifty five hours until the pumps could be restarted after the underground pump chamber had been evacuated, the electrical wiring rebuilt, and the pumps reconditioned so that they could operate.

9. Attempts to open the penstocks using emergency power which would have allowed a discharge to the cliff face were unsuccessful as a consequence, so it is alleged, of a failure to maintain them in a satisfactory operating condition.

10. The prosecutor contended in an earlier Case Stated for the Court of Criminal Appeal that the defendant has made relevant admissions in its own documents. The alleged admissions are set out in full below as a convenient explanation of the underlying facts and contentions upon which the prosecutor relies. They were repeated by Mr Glissan in his final submissions as facts relied upon by the prosecutor to establish its case.

11. A plan of the sewage flow and plant location tendered as Exhibit 4 is reproduced firstly to assist with an explanation of the way in which the plant operates and also to enable the various items within the plant to be identified.

a) Licence number 000378 was issued to Sydney Water by the EPA pursuant to the Pollution Control Act 1970 in respect of the period 1 July 1994 to 1 July 1995.

"Pollution control equipment, fuel burning equipment or industrial plant installed in or on the premises must be maintained in an efficient condition and operated in a proper and efficient manner. "

c) The industrial plant referred to in condition L4 can be regarded as the whole of the North Head Sewage Treatment Plant (sewage treatment plant) of Sydney Water's premises at Darley Road Manly in the State of New South Wales.

d) Under the Clean Waters Act 1970 conditions, or the W conditions, Sydney Water was authorised to discharge waste water from three points of discharge. The first is discharge point 01 being the deep ocean outfall on the seabed approximately three kilometres east of Blue Fish Point Cliff face. The other two are emergency discharge points, namely, discharge point 02 being the shoreline ocean outfall (submerged) east of the sewage treatment plant located at the base of Blue Fish Point Cliff face, and also discharge point 03 being the shoreline emergency discharge pipeline east of the sewage treatment plant located at the base of Blue Fish Point Cliff face.

e) Condition Wl of the licence meant the sum of the volumes of waste water discharged from discharge points 01 and 02 shall not exceed 1,002,700 kilolitres per day.

f) Condition W12.4.2 of the licence meant the cumulative duration of all events involving the bypass of a treatment process caused by the failure or malfunction of essential equipment over the licence year was required to be less than 48 hours.

g) Between 3 to 8 March 1995, extensive rain in Sydney meant there were flows into the sewage treatment plant, via its North Shore Ocean Outfall Sewer (NSOOS) inflow point, of an average of 760 megalitres per day, compared to an average dry weather flow of 280 megalitres per day.

h) The sewage treatment plant relies on three out of four large raw sewage pumps (RSPs) to give it a pumping capacity of 1,050 megalitres per day, with the fourth RSP usually being out for maintenance or overhaul.

i) At 3 am on the morning of 7 March 1995, when there was a flow of about 700 megalitres per day rate, all of the three available RSPs were operating.

j) At 3.13 am, Sydney Electricity experienced a power failure for the whole southern section of the northern peninsula caused by an interference with its 33 KV sub station equipment. This power failure lasted until 4.44 am.

k) The two emergency power generators at the sewage treatment plant cut in immediately to supply power needs for underground equipment including lights, ventilation, lifts and penstock controls. But the emergency power generators did not and do not have sufficient capacity to operate any of the RSPs.

l) Due to the unavailability of the RSPs to lift the flow of the waste water 60 metres above ground for sedimentation and discharge to the deep water ocean outfall, the sewage treatment plant switched to a cliff face outfall mode or a discharge to discharge point 02.

m) Difficulty was experienced by Sydney Water's production officers in operating seven penstocks needed to put the sewage treatment plant in the cliff face outfall mode, namely, the penstocks are intended to facilitate the flow of waste water to the cliff face and enable the water level in the inlet and outlet channels of the sewage treatment plant to drop. The seven penstocks were the pump suction channel bypass penstocks (PE1433 and 1434), the outlet channel penstocks (PE1306 and 1307) and the NSOOS bypass penstocks (PE1301, 1302 and 1303). In a cliff face outfall mode they are needed to be put in an open position, rather than the closed position in which they had been respectively maintained.

n) These penstocks were found to be inadequate as it took three hours to open six of the above penstocks, ie other than one of the NSOOS bypass penstocks which could not be opened at all. The inadequacies were due to: blown fuses in the penstock controls; the penstocks stuck fast in their seats; the previous failures of Sydney Water to exercise the penstocks in order to ensure they were maintained in working order; and the difficulties the underground operators experienced in attempting to open them by hand wheels when faced with the high force of storm water.

o) The difficulty in operating the penstocks, combined with the 700 megalitres per day flow, meant the waste water level in the sewerage treatment plant's channels rose to a much higher level than normal.

p) The waste water flowing in the sewage treatment plant overtopped the pump suction channel penstock for RSP 1 (PE2311), it then entered the suction well of RSP1 (some 60 metres in height) and then flowed out of an opening in the body of RSP1 into the RSPs' chamber. This 6 metres high chamber was flooded to a height of 5.5 metres with the consequence that the electrical control equipment for the RSPs, located in the chamber, was also flooded and thus rendered inoperative.

q) The waste water was able to enter the suction well of RSP1 as PE2311 was overtopped because this penstock did not seal RSP1 from the rising waste water in the pump suction channel. Stopboards had not been used to give this penstock extra height and therefore a level of flood protection. Prior to about December 1994, the original pump suction penstocks gave protection against flooding by completely sealing the RSPs, including RSP1, during pump overhauls which meant dismantling took place. These original penstocks were higher in the closed position than the ones maintained in place on 7 March 1995 at the sewage treatment plant.

r) The pump body and the motor of RSP 1 were dismantled as at 7 March 1995 for major overhaul and this meant the pump body was therefore opened.

s) The sewage treatment maintenance manual for the RSPs made no mention of flood prevention precautions prior to 7 March 1995. Subsequent to 7 March 1995, Sydney Water, during RSP motor removal for the purpose of overhaul, has installed a "Tee Pee" into the pump housing and bolted it into place as a second level of protection against flooding.

t) The flooding of the RSPs, the RSP chamber and the electrical control equipment, meant the plant could not be returned to deep ocean outfall mode at 4.44 am when Sydney Electricity returned power.

u) When the above six penstocks were opened, the waste water level in the inlet and outlet channels gradually fell below the level of the opening of the pump body in RSP1 and recovery activity could then begin on behalf of Sydney Water.

v) It took Sydney Water 56.5 hours to re-establish normal plant performance and to cease the by-pass to the cliff face discharge point 02.

w) The overflow weirs and the 7section siphons were alleged on 21 March 1995 by Sydney Water to be capable of handling wet weather flows so long as outlet channel penstocks PE 1306 and 1307 were open. Furthermore, prior to 7 March 1995 they were left in a closed position to contain "small" overflows (ie 2-3 megalitres) from the inlet channel, thus preventing cliff face discharge.

x) From 30 June 1995, Sydney Water maintained the outlet channel penstocks PE1306 and 1307 in an open position in high flow periods, ie 600 megalitres per day.

y) In 1995, Sydney Water had a total of six bypass events to the cliff face, of which five were a direct result of power supply failure/irregularity or control failure of the RSPs of the sewage treatment plant.

13. Following argument at the commencement of the hearing, I determined by a preliminary decision made on 4 November 1996, for reasons published on 6 November 1996, that:-

1. The Court was satisfied that consent given by the Director General of the EPA on 4 March 1996 pursuant to s 13(1)(a) of the EOP Act was a consent to the institution of proceedings in respect of one offence.

2. That Condition L4 imposes two separate and distinct duties upon the licence holder. The first obligation is to maintain the equipment or plant in an efficient condition. The second is to operate the same in a proper, efficient manner.

3. There is no question of the prosecutor making an election as to which alleged offence is to be prosecuted because only one offence has been alleged, namely that the industrial plant was not maintained in an efficient condition contrary to Condition L4.

In his closing address Mr Glissan submitted that the gist of the EPA's case is that the defendant failed to put its North Head Sewage Treatment Plant in a proper state so as to permit the plant to dispose of sewage effluent arising from the operation of the plant as follows:-

(a) During about 90 minutes of a mains power failure at the STP (or in other words in an emergency condition), to discharge point 02, namely, the shoreline ocean outfall located at the base of Blue Fish Point Cliff face, and

(b) Subsequent to the restoration of mains power (or in other words when normal operating conditions were restored), to authorised discharge point 01, namely, the deep ocean outfall on the seabed approximately three kilometres east of the Blue Fish Point Cliff face.

It is further submitted that, even on a narrow meaning (although it is not conceded that it would be inappropriate for the Court to apply the wide meaning), the defendant's entire plant was "industrial plant" as it was involved in the treatment of materials and substances, namely the sewage effluent, and its subsequent disposal for the purpose of preventing or minimising pollution on the shoreline. The plant can be regarded as a single entity wherein the free flow of liquids is interrupted or controlled by individual items of plant.

The primary submission of the prosecutor is that there was a contravention of condition L4 as the "industrial plant" (as a single entity) was not maintained in an efficient condition. The single offence alleged from the summons is a contravention of condition L4 and, according to the prosecutor, in order to succeed it need only establish one of the particularised aspects of the failure to maintain the sewage plant in an efficient condition as follows:-

failure to carry out necessary mechanical and electrical maintenance to ensure that the penstocks would operate in an efficient manner when required and/or a failure to replace damaged components.

failure to maintain penstocks of a sufficient height to effectively control the flow of sewage. In the context of this particular, "sufficient height" is a height in excess of the height of those penstocks (with stopboards installed) being penstock numbers PE1301, PE1302 and PE1303.

failure to carry out maintenance by use of a "Tee Pee" or a blanking flange to prevent flooding.

Milo Julius Taragel, a civil engineer with over thirty years experience, inspected the North Head plant after March 1995 at the request of the prosecutor. He concluded that normal operations of the plant would be that the NSOOS bypass penstocks PE1301, PE1302 and PE1303 would be in the totally closed position with the outlet channel penstocks PE1306 and PE1307 in the fully open position. Mr Taragel calculated that inundation of approximately 0.5 metres within the RSP chamber would have been sufficient to cause electrical failures in the electrical control system. That could have occurred within a period of seven minutes after overtopping of penstock PE2311. It is his opinion that in emergency situations, such as that which occurred on 7 March 1995, penstocks must be capable of being operated within a period of seven minutes. In his view there would have been a period of less than ten minutes after the loss of power to the raw sewage pumps for the electrical control equipment which powered those pumps to b e rendered inoperative.

Given the circumstances which occurred on 7 March 1995, Mr Taragel told the Court that, in order to prevent inundation of the plant, penstocks PE1301, PE1302 and PE1303 at the entrance of the bypass channel and penstocks PE1306 and PE1307 at the exit of the outlet channel would have required immediate and quick activation.

Finally he stated that inundation of the raw sewage pumping area through the open pump casing may not have occurred, or may not have occurred to the same extent, if the height of the pump suction penstock PE2311, which was installed between June and December 1994, had been the same height as or higher than the penstock it replaced.

That Mr Taragel gave his evidence in chief with the benefit of hindsight and without any opportunity to personally experience what occurred on 7 March 1995 is evident from the following passages of cross examination:-

Q. When the work was being done on the maintenance of pump number one, assume that you were there at the time, if you had believed that the penstock 2311 closed off any sewage coming into that area, you wouldn't have put a flange on the pump would you?

Q. Well you smiled before you gave that answer, you smiled because it was a tricky question for you to answer was it?

A. No I smiled because I wasn't quite sure what I would do unless I was faced with the situation I guess.

Q. Well assume that you were there and it was your job to dismantle the sewage pump number one and was your belief that the penstock 2311 closed off the area. You wouldn't have put a flange on it would you?

Q. You've looked at the drawings which have been prepared of the plant itself out there haven't you?

Q. You've seen the structure and is it your understanding from seeing the drawings and seeing what is in fact constructed that there's been a change of - change in operation of that plant over the years?

A. The plant was purpose built for a certain operation, I don't think it has changed.

Q. Well initially there was no deep ocean outfall was there?

Q. And when the deep ocean outfall was constructed, doesn't it appear to you from the way the plant is configured that the NSOOS bypass penstocks would remain closed?

A. I'm not really sure about that, I think they would still retain their original functionality, namely diversion, specially in regard to perhaps the fact that as I understand it the outlet channel penstocks had been maintained in a closed position because of leaking stop boards etcetera.

Q. So once again there was no intention in the way that plant was being operated, to allow there to be an outfall over the cliff face through the NSOOS penstocks?

A. I believe that the penstocks are there for a purpose and that is to fully relieve the plant under emergency conditions.

Q. Well that's what they might have been there originally for. What do you rely upon to give that evidence as at today?

A. Because it seems the logical way of doing it, the relieving the plant of an emergent inflow.

Q. And in paragraph 8 of your affidavit at the bottom of page 2 you talk about the purpose of the siphon structure?

Q. Would you agree that whether there be an abnormally high flow or a normal flow, the plant is designed to take all of that flow, treat it and discharge it to the deep ocean outfall?

A. Yes. In relation to item 8 I'm not quite sure --

Q. Will you agree with the proposition I'm putting to you?

Q. You see what you've said in paragraph 8 of your affidavit is that the purpose of the siphon structure is to relieve the down stream installation of abnormally high or peak flows which may occur?

Q. What I was putting to you in that question was that it doesn't matter how high the flow might be, it is all taken into the plant and treated and discharged to the deep ocean outfall?

A. It is all taken into the plant. I am not really sure that it would all be treated, possibly most of it would be treated.

Q. Now you saw a bent spindle near the NSOOS outlet penstocks?

A. Outlet or in the pen stock, one of the early penstocks.

Q. And would you agree that the fact that it had that bend in it would have an impact on the downward movement that could be applied to it towards the end of the movement?

A. The longer the unsupported spindle distance gets yes the more effect a bend would have on the spindle, that's assuming it doesn't sort of run in through the journal guides or something like that of the bearing box.

Q. And would you agree that that bend in that spindle would not affect it being opened upwards?

A. Probably not but I'm not aware of the actual physical way the thread of the spindle runs through the box.

Robert Andrew Marr, the Senior Regional Operations Officer for the prosecutor also came to the conclusion that if the NSOOS bypass penstocks, PE1301, PE1302 and PE1303, had been open, there would have been an unscreened bypass to discharge point 02. In addition, had the outlet channel penstocks, PE1306 and PE1307, been open with the NSOOS bypass penstocks closed, then there would have been a screened bypass as the emergency power would have operated the screening chamber. He based these conclusions, as did Mr Taragel, on a perusal of the documents produced by the defendant and from his experience of dealing with the plant. He also gave the opinion that the pumps in the pumping area could have been protected by the use of a blanking flange to protect RSP 1, which was at the time of the incident in the process of being overhauled, and that in addition stopboards could have been installed at the entrance to the pumping chamber to minimise access of the sewage.

Mr Marr and the Head Northern Operations Outer Sydney for the prosecutor, Mr John Sparkes, gave evidence of conversations which took place when officers of the defendant attended the prosecutor's office at Chatswood for the purpose of providing a presentation regarding the bypass which occurred on 7 - 9 March 1995. Those conversations are relied upon by the prosecutor to prove that the plant was not kept in an efficient condition so that it was in a state which enabled it to serve the purpose for which it exists. Relevantly, in the present case, this arose from a failure to test the penstocks and penstock controls on a regular basis and an omission to take precautions against the risk of the failure of the power source from Sydney Electricity. The Court is not able to place significant weight on what is alleged to have been said by the defendant's officers at this meeting, as no formal record was made of the words spoken until over a year later. There is also a strong suggestion, although denied, that the prosecutor's witnesses collaborated to reconstruct the terms of the conversations at a later date.

There were six production officers operating the plant during the shift when the incident occurred, but none of these officers were called to give evidence on behalf of the defendant.

Michael Dumer, a mechanical engineer employed by Australian Water and Technology Pty Ltd which is a subsidiary of Sydney Water Corporation Ltd, produced a commissioning report in respect of the penstock installed for RSP 1. Commissioning took place on 14 April 1994 when the penstock was conditionally commissioned subject to completion of some outstanding items. It was opened and closed. The limit and torque switches were checked. As the commissioning engineer, it was his duty to ensure that the penstock is manufactured in accordance with specific drawings and installed in accordance with the drawings. He had no other function in relation to the operation of the plant as a whole.

Eric Ralph de Rooy is a civil engineer who at the relevant time was the Sewage Treatment Manager at the North Head Sewage Treatment Plant. Mr de Rooy explained the operation of a Works Information Management System (WIMS) which generated, from a computer work order, dockets of works to be carried out at the treatment plant from time to time. The system was programmed to generate the documents for the maintenance providers. The computer was programmed to produce information in respect of the work to be completed during each week of the year. The intention was that the dockets would be distributed to relevant workmen who would note completion of the work after it was finished. The results of the work would be put back into the computer to reflect the work that has been completed. He told the Court that at the time there was a regular maintenance program for mechanical works and for electrical works. In addition, if work was done following a failure or breakdown, a job order would be issued under the same sy stem and recorded in the same way.

When asked how well the workmen complied with their instructions to put the information into the computer after they had done their work, Mr de Rooy said that they did it "reasonably well". He could recall occasions when, although the work had been carried out, an appropriate entry to that effect had not been made.

Mr de Rooy said that, during his period of working at North Head, it was policy for the NSOOS bypass penstocks to be kept closed as they were there for bypass only. Under normal operation they would always be kept closed. They were only there for bypass through the plant over the cliff face, rather than the intended design to get the sewage to the deep ocean outfall.

Shortly after Mr de Rooy commenced working at the plant in 1993, a decision was made to leave the outlet channel penstocks closed under normal conditions. He explained that given the dynamics of the plant, when the raw sewage pumps tripped out under voltage variations in the incoming power supply, there was a risk of some minor discharge to the ocean over the cliff face bypass. It had been demonstrated that by having the outlet penstocks closed, there was enough capacity in the outlet channel to pick up any of the discharge with the siphon or the stopboard weir thereby avoiding a bypass to the cliff face. After the tripping event occurred the flow trapped in the outlet channel would be pumped back into the plant for treatment. Up to about half a megalitre of sewage could be trapped in the outlet channel.

It is possible to reconcile the apparent conflict between the evidence of Mr Taragel and Mr de Rooy in regard to whether the outlet channel penstocks were to be left open in normal operation by recognising the operational changes brought about by the switch to deep ocean outfall which Mr Taragel did not appear to take into account or fully appreciate. However, both witnesses gave logical explanations for the proposition they supported. In the end it comes down to whether leaving the penstock closed was justified under normal operations. The Court accepts that one of the aims of keeping the plant in an efficient condition is to minimise the extent of pollution to the ocean. It was reasonable therefore to keep the outlet penstocks closed during normal operations to prevent unscheduled and uncontrolled discharge to the cliff face during times of high flow.

Mr de Rooy said that he was aware of a bent spindle on penstock PE1301, but that mechanical maintenance experts had carried out some tests and they reported that it was no impediment to the operation of the penstock.

Mr de Rooy gave evidence that maintenance work had been done on the raw sewage pumps quite often during the time that he was Manager of the plant, but there was no occasion when a blanking flange was used on the pump. When asked whether he had an opinion as to whether a blanking flange should be put on when that type of work is done, he replied as follows:-

After having reviewed the design intent of that system, the WIM system, there was a fully sealing penstock to be in front of the pumps and that provided a fully effective barrier to that particular pump and, in that sense, it could be relied upon, in my opinion, to keep the sewage out of that particular pump. In that sense, a blanking flange was a redundant issue.

In cross examination Mr de Rooy demonstrated that there was the capacity to pass all inflow to the cliff face without opening the bypass penstocks by taking all of the flow over the stopboards, through the siphons and out through the outlet channel to the cliff face.

In cross examination Mr de Rooy explained the failure of the penstocks in the following way:-

Q. They failed to open because of a mechanical problem with the seating, is that right? That is how I understood your earlier answer?

A. They failed to operate, in my understanding, because when the operator pushed the "up" button, the penstocks went down, rather than up. They went down, rather than up, because the emergency power phasing was in reverse phasing to the general normal power to those penstocks.

Q. That was, of course, something that routine maintenance components involved checking; both maintenance and emergency power?

A. That is not a process under routine maintenance, no.

Q. Had it been, the defect would have been revealed?

A. There was routine maintenance on the electrical generator system. To check it fully would require the plant being switched off normal power and put on emergency power and which would have resulted in quite a significant by-pass.

Q. You could, surely, isolate equipment and supply emergency power to equipment on a sectional basis?

A. My understanding of the layout of that is that they use the same power boards for emergency power as normal power and in that sense you cannot have both on at the same time. So, all the equipment on those power boards would have to have been under emergency power.

The emergency power supply and the attendant systems were tested every six months. The maintenance on the actual motors of the equipment meant, according to Mr de Rooy, that all the conditions were there for the penstocks to be open when it was needed. There was in place an instruction not to open the penstocks by mechanical means to determine whether they would work, otherwise there would have been unauthorised discharge over the cliff face.

On 7 March 1995 it was not possible to lift the bypass penstocks by mechanical operation because the powerful electric motors had driven them down into the seat. Ultimately, when power was restored, the penstocks were cranked up from the seat where they had been driven down by the motor working in the reverse mode and thereafter they were driven up electrically.

Mr de Rooy did not become aware of the potential for penstock PE2311 to overtop until the system was reviewed in the aftermath of the incident. He agreed, with the benefit of hindsight, that there was a possibility that the pump body which had been left open could have been closed off with a blanking flange. The maintenance procedure undertaken during 7 March had been done about twenty times to the knowledge of Mr de Rooy and had proved adequate in his opinion. It was outside of his experience to have a failure in the electricity supply of the magnitude that was experienced on that day.

When Mr Glissan suggested to Mr de Rooy in cross examination that the plant was left in a "fail to danger", rather than a fail safe, situation he responded that the bypass penstocks were not relied upon to be an operational feature of the plant but were there only for a planned shutdown of the facility.

He explained that the outlet channel penstocks were used with the inlet channel penstocks and the bypass penstocks in the same coordinated effort to put the plant on bypass. By opening up the bypass penstocks only, there would still be sewage flowing into the screenings chamber area. It would be necessary to close the inlet penstocks to stop that and then to close the outlet penstocks to stop it coming back the other way, through the outlet channel and back into the facility. Accordingly the design of the inlet and outlet penstocks was in concert with a planned shutdown of the facility.

He does not agree that it was necessary to fully exercise the operational penstocks on a routine basis. In his opinion, opening them a distance of 150 mm is adequate to demonstrate the capacity of the system to operate. If you lift them off the seat with 150 mm of travel, his experience told him that it would be adequate to give the necessary confidence that they would travel the full distance. The operational penstocks were exercised to that extent on a regular basis.

In the event of 7 March 1995, all of the flow that came into the plant was contained in the channel apart from the flow that went into the RSP chamber. Mr de Rooy contended that the plant was at no time flooded in terms of the walkway above the channels and that the design of the system in its entirety is such that the plant will not flood, even with the outlet penstocks closed. He could not agree with Mr Glissan that keeping the emergency bypass penstocks closed put the plant at risk and created a risk for a much more prolonged bypass.

Mr de Rooy concluded that the risk on 7 March was due only to the fact that there was a penstock in front of the raw sewage pump that did not seal. Even in that event, all flow exited the plant without coming out of the channels.

The first time the prosecutor and the Court became aware of the claim that the emergency power was in reverse phase was during the evidence of Mr de Rooy. Thereafter the defendant relied on several further witnesses to show that the difficulty with the operation of equipment, including the penstocks, was because the phase rotation within the emergency power circuit was not synchronised or matched.

John Edward Humphrys, a qualified electrical technician and a licensed electrician, was an overseer of work in August 1995 when generator 7377 was physically moved from another building to the first aid room in the administration block in order to give back up power to generator 7316.

In order to connect the two generators, a tie line was installed between the two machines. When the normal electricity supply drops off, a changeover contactor operates to bring in the emergency supply. In order for the supply to be the same polarity a test had to be made as to what phase rotation the generator was at that point so that there would be the same phase rotation on the plant. When the tie line was connected it was necessary to check the phase rotation of the line to ensure that it matched the phase rotation of the additional cell on the main distributor board which supplies emergency power.

When the phase rotation test of the line was undertaken in August 1995, Mr Humphrys found that the phase rotation of the tie line did not match the phase rotation of the cell which had been previously bolted to the main distribution board. Prior to the addition of the additional cell to the main switchboard there was no emergency supply to that board.

Mr Humphrys supposes that, if in March 1995, the phase rotation of the cell was as it was found to have been in August 1995, then the supply of emergency power to the underground penstocks would have caused them to operate in the reverse mode to that which they were directed to operate. In other words, he said, if the phase rotation was incorrect in March 1995 as it was in August 1995, an operator pressing the "up" button on an underground penstock would have caused the penstock to be forced downward.

Mr Humphrys explained that the phase rotation is readily changed by switching two wires.

He did not think that it would have been necessary to trial the penstocks with the generator as any trial would take place with normal supply to ensure that the cells are correctly connected. However, it would have been possible to check the generator phase rotation in the changeover contactor. The RSPs were not attached to the emergency power section of the switchboard.

He said that the rotation on any individual piece of machinery can be checked by giving it a "bump".

He also agreed in cross examination that the emergency generator could be tested by attaching it to an item of plant or machinery to put a dummy load on it. Alternatively the loss of normal supply could be simulated by pulling a trial fuse causing that contactor to fall out and the generator to start up. In that case there would be an interruption to the operation of any equipment of around ten or fifteen seconds.

Brian Ian Whichlow is a qualified fitter and machinist employed as a production officer by the defendant. From March 1992 to November 1994 he was the Operations Superintendent at North Head Sewage Treatment Plant.

Mr Whichlow's responsibilities were confined to day to day operation management which excluded any responsibility for maintenance or design and construction.

In about July or August 1992 he developed a proposal to increase the storage to enable further time to respond to power spikes which up till then had been the underlying cause of a number of discharges to the cliff face. As a consequence the outlet penstocks were totally rebuilt and put onto emergency power via a 500KVA generator.

The decision was made to keep the penstocks closed. They were never opened again in his time at the plant.

The closure of the outlet channel penstocks was intended to provide additional storage to prevent overflow at points upstream of the plant, such as Quakers' Hat and The Spit.

Mr Whichlow personally physically ran the new penstocks up and down a number of times to check their sensitivity.

Mr Whichlow remembered that following the collapse of a coffer dam within the system, it became necessary to shut the plant down while timber debris from the coffer dam was removed from the suction channel. The penstocks to the RSPs were closed while the timber was physically removed by a person on a life line. During that incident the outlet channel provided the additional storage required while the pumps were not operating.

Mr Whichlow further explained that the bypass penstocks also permanently remained in the closed position to avoid bypassing plant.

Mr Whichlow stated that the penstocks could not be operated with emergency power without shutting down the whole plant.

Brian Gassman is an engineer who was the Commissions Manager Ocean Outfalls in the Pollution Control Branch of Sydney Water Corporation in 1990 when his role was to assist in the commissioning of the deepwater submarine ocean outfall.

After the event which occurred on 7 March 1995, Mr Gassman was asked to investigate the flood incident and in particular the works that had been carried out on the pump suction penstock 2311.

On 19 September 1995 Mr Gassman reported to Mr de Rooy that his investigation showed that originally the pump suction penstocks could not be overtopped as they sealed completely when closed and that during pump overhauls where dismantling took place, protection against flooding was provided by the completely sealed penstocks. However, he subsequently discovered that the basis for this report was founded upon incorrect information furnished to him in regard to the original penstocks.

Following inspection of a plan, which included a depiction of the original suction channel penstocks, he agreed that even if the replaced penstock did not seal to the full height, it would still have had the effect of only leaving a small space for any fluid to pass over the top of the penstock. He accepted that the space would be a matter of inches or parts of an inch. He agreed that it represented a very small gap.

He further agreed that in the ordinary course of events, taking into account the relative levels, he had determined that the first penstock to overtop would have been the suction channel penstock with the consequence that there would be inundation of the pumps in a situation where one of the pumps was dismantled for maintenance.

According to Mr Glissan, it does not matter how you look at the issue of maintenance. It was either because there was a fault in the penstock controls, the height of the suction channel penstock was inadequate, or there was a failure to blank off the RSP inlet, or a combination of any or all of the three reasons that the plant was not, on 7 March 1995, maintained in an efficient condition.

The defendant is charged with an offence for an alleged contravention of a condition of its pollution control licence. The act of pollution which occurred as a consequence of the discharge over the cliff face is not an element of the offence, but a consequence of it.

A pollution control licence issued for the purposes of the Clean Waters Act constitutes an authority to pollute waters in a way which otherwise would be contrary to the provisions of the statute which forbids such an act. Pollution of waters in accordance with the conditions of a licence is not an offence arising under s 16(1) of the Act. The construction of Condition L4 must therefore be regarded in that context.

The "efficient condition" referred to in Condition L4 is one that has as its primary objective the minimisation of pollution or the risk of pollution. It has nothing to say about the effective operation of the plant for any other purpose except where it is coincidental to the control of pollution. Questions of fact and degree arise in each case taking into account the standard of pollution control expected by the community through the licensing authority and commercial considerations on the part of the licence holder (Genkem Pty Ltd v EPA (1994) 35 NSWLR 33 at 41).

One sense of a requirement to maintain is to keep an item in repair and a proper and fitting condition for its design purpose. It is difficult to see how a piece of machinery could be regarded as being maintained in an efficient condition over a given period, such as the duration of a licence, if, at some particular time within that period, the machinery fails to function because it is not in proper working order. In other words, when it is required to carry out the function for which it is designed, setting aside an accident or other unforeseen circumstance, the machine should perform the requisite function.

Condition L4 raises a clear distinction between the obligation to maintain the industrial plant in an efficient condition and the obligation to operate the plant in a proper and efficient manner. The former, in my opinion, addresses the capacity for the plant to function, whereas the latter seeks to prescribe the manner of carrying out or regulating the actual use of the plant while it is functioning. The prosecutor has chosen to address a failure to comply with that part of Condition L4 which deals with the static condition of the plant rather than the regulation and management of the operation of the plant while it is actually performing the industrial process.

The Court is satisfied that the defendant was not obliged by Condition L4 to maintain the outlet penstocks in an open position during normal operation of the plant. If there was a duty to keep the outlet penstock open, it would arise pursuant to the second part of Condition L4 which is not part of the present charge. If it became necessary to decide, the Court would place greater reliance on the evidence of Mr de Rooy in this respect having regard to his direct involvement with the day to day management of the plant at the relevant time. Mr Taragel lacked the practical familiarity with the operation of the facility and furthermore was not able to be categorical about the decision he would have made if given the actual responsibility. The explanation given by Mr de Rooy was corroborated by Mr Whichlow.

The next question to be addressed is whether the defendant was obliged pursuant to Condition L4 to maintain the plant in a way that anticipated that the outlet or bypass penstocks would not open in an emergency during high flow and to cover the contingency of sewage entering the pumping chamber at a time when a RSP had been dismantled for routine maintenance. This aspect of the contributing cause to the inundation of the pumping chamber is prima facie a design matter in respect of the height of the penstock. However, whether a blanking flange or tee pee was necessary to satisfy the condition demands consideration.

The Court must also determine whether the failure to detect and correct the error in the phasing through the emergency switchboard was a failure to maintain the penstock controls in an efficient condition. There is no reason why the necessary proof and admissions may not be proved by the defendant witnesses (EPA v Sydney Water Corporation Limited (1997) 98 LGERA 361). Although the witnesses for the prosecutor did not, as part of the prosecution case, provide a plausible explanation for the failure of the penstocks to open under emergency power, the incorrect polarity or phasing is nevertheless arguably an aspect of the penstock controls covered by the particulars which allege a "failure to carry out necessary ... electrical maintenance to ensure that the penstocks would operate in an efficient manner when required...".

The provision of a tee pee or blanking flange appears to be important only when one of the RSPs has been dismantled for maintenance purposes. It would be curious if the defendant could be found to have failed to meet an obligation to maintain the plant while it was in the course of undertaking that very procedure. The method of operating the plant during maintenance might have to be modified according to the extent that the work might interfere with the efficient and proper manner of operation. However, that is distinct from maintaining any part of the plant, or even the whole of it, in an efficient condition. Again it is important to bear in mind the specific obligation which arises under Condition L4 in the present context.

The defendant's case is that the penstocks did not open because the phase rotation of the tie line did not match the phase rotation of the emergency cell on the switchboard.

Although the proper maintenance was carried out from time to time according to the WIMS system, the programme did not identify the very problem that existed with the penstock controls in an emergency situation. The Court accepts that the penstock controls were effective under mains power. However, the plant was designed to cope with an emergency situation and the success of dealing with the unexpected depended upon the controls being maintained in an efficient condition while emergency power was being supplied through the switchboard. Although it has not been finally demonstrated that a check should have been undertaken in a specific way, nevertheless the Court is satisfied that the opportunity existed to carry out a test to facilitate an understanding of whether the penstocks would operate under emergency power. This was not done with the result that, on the relevant day, the controls operated in reverse, and accordingly did not function efficiently.

It is not to the point that the incorrect connection may have been made prior to the licence period. The main distribution board was an integral part of the whole plant, including the penstocks, which depended for its operation on an efficient supply of electricity either from the mains supply or the emergency generator.

In one respect, it might be argued that the electrical defect was operational or a matter of design or construction fault. There was nothing faulty about the design or the intended operation.

The tie line had been connected in the reverse order and therefore the controls were inefficient and did not function as expected because they had been maintained incorrectly. A routine periodic check of the type undertaken on other parts of the plant would have revealed the fault. Because these checks were not undertaken the fault was not revealed and hence the defendant failed to comply with its obligation to maintain the penstock controls in an efficient condition.

I do not accept that it was necessary to close down the whole plant in order to carry out a test with emergency power.

Mr Robberds developed an argument, based on the construction of Condition L4, that attempted to distinguish industrial plant from pollution control equipment and fuel burning equipment. There is no evidence which shows whether there is any piece of equipment at North Head which had control of pollution as its sole function. Nor has the Court been given any understanding of what is referred to as fuel burning equipment. He contends that each of the items the subject of this prosecution is pollution control equipment because the penstocks regulate the flow of sewage and prevent the pollution of waters. Furthermore the RSPs regulate the flow of sewage and similarly prevent the pollution of waters.

In its general ordinary sense an industrial plant is to be understood as a factory or an installation comprising appliances, machines or equipment engaged in production or manufacture of commodities or the treatment and processing of materials.

Pollution control equipment may be an integral part of the industrial plant or it may exist as a separate entity.

In the present case the question of whether the penstocks are pollution control equipment as such does not need to be determined because the Court is satisfied that they comprise an integral part of the whole entity comprising the North Head Sewage Treatment Plant which itself operates as an industrial plant receiving and treating sewage and other wastes before the treated effluent is discharged through the deep ocean outfall.

I find after considering all of the evidence and the submissions made on behalf of both parties that the offence is proved beyond reasonable doubt.

The question of conviction, penalty (if appropriate) and costs is reserved.

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