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Legislative Council - Fifty-Third Parliament, Second Session (53-2)
2017-05-09 Daily Xml
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Wastewater Discharge

The Hon. M.C. PARNELL (15:57): At the risk of testing the minister's voice even further, I do seek leave to make a brief explanation before asking the Minister for Water and the River Murray a question in relation to wastewater discharge to the marine environment.

Leave granted.

The Hon. M.C. PARNELL: Last Friday, 400 metres of beachfront at Christies Beach was closed as a precautionary measure when up to six megalitres of unchlorinated water from the Christies Beach Wastewater Treatment Plant was released into Gulf St Vincent. According to SA Water, the discharged water which caused the scare had been cleaned and treated, but the lack of chlorination meant that it was not disinfected. Without disinfection, people who came into contact with the water could have experienced diarrhoea and vomiting.

It appears that the discharge was due to a fault with the plant's automated chlorination system and monitoring alarm which, according to SA Water, has now been fixed. This incident draws attention to the fact that, some 16 years after the establishment of the Adelaide Coastal Waters Study and four years after the release of the Adelaide Coastal Water Quality Improvement Plan, we still have a situation where effluent from Adelaide's metropolitan wastewater treatment plants is being discharged to the sea where concentrations of nutrients, such as nitrogen, have had a devastating impact on seagrasses and other marine life.

Over the years, diversion programs have seen some wastewater from Bolivar, Glenelg and Christies Beach wastewater treatment plants being used for parks, gardens, orchards, vegetables and vines. In the case of Christies Beach, some of the water is being diverted for urban use under the Southern Urban Reuse Scheme and for agricultural use under the Willunga Basin pipeline.

My questions of the minister are: firstly, when will Adelaide's wastewater treatment plants, in general, and the Christies Beach plant in particular, stop discharging wastewater to the marine environment? Secondly, how likely is it that the EPA's target of limiting total nitrogen discharge to the marine environment to 100 tonnes (that's from Christies Beach) will be achieved, given the expanding population in the southern suburbs?

The Hon. I.K. HUNTER (Minister for Sustainability, Environment and Conservation, Minister for Water and the River Murray, Minister for Climate Change) (15:59): I thank the honourable member for his most important questions. Most importantly, I thank the honourable person who sent me a cough lolly, anonymously.

The Hon. K.L. Vincent interjecting:

The Hon. I.K. HUNTER: She has fessed up to it. I am very grateful. It was to get me through this hard, tortuous question the Hon. Mark Parnell has forced on me.

I will give you a few facts about the Christies Beach discharge first and then I will go on to the magnificent effort of SA Water to decrease the amount of nitrogen discharged to the gulf over the previous 10 years or so and its massive investment. My understanding is the reduction of nitrogen to the gulf has been 75 per cent. That is a massive reduction in the amount of nitrogen that goes out to the gulf. I think honourable members should understand that.

I am advised that an unplanned discharge at Christies Beach Wastewater Treatment Plant resulted in the release of clean and treated but undisinfected wastewater being discharged to the ocean. I understand it was about six megalitres—about 2½ swimming pools' worth. It is understood the system fault with the plant's automated chlorination system and monitoring alarm occurred overnight on Friday 5 May. I am advised the fault was detected during routine checks on the morning of Saturday 6 May. The affected piece of equipment was immediately reset, I am advised, with additional alarms put in place. The chlorination system and plant returned to normal operation at approximately 9am on Saturday 6 May.

I further understand that testing received on Monday 8 May confirmed that water quality was not degraded by the incident. The water is and was safe for swimmers and fishers. As a matter of fact—and I think honourable members will probably agree with me—I prefer caution to otherwise not putting out an alert. Whilst you don't have all the information before you—and I agree with SA water practice here—if you are advised of this sort of situation, you should take every step to warn the public not to go into the sea water until such time as we can confirm that there is no risk of contamination.

I am advised that in this situation, there was none, but we didn't know that at that point in time and so the best practice was to put out a beach alert. I know that was inconvenient for users of Christies Beach, but my preferred course of action is to be better safe than sorry and to avoid swimming in the water until such time as we can confirm there is no danger for the public.

So, the closure of the beach in this instance was undertaken as a precautionary measure until the results were known, as is the usual practice. Although this is not something that occurs very frequently, I am also advised, and this is from memory—it is a pretty hazy memory right now but the Anticol will fix that up, I'm sure; thank you, Hon. Kelly Vincent—we haven't had a situation like this at Christies Beach for about seven years. It is an infrequent event—our maintenance schedule sees to that—but it does happen very infrequently.

Following the receipt of advice from SA Health, the beach is now open again. I apologise to honourable members who don't want to know this amount of information; they can just block their ears for this one. During the incident, all solids and organic matter from the plant continued to be treated, but the final disinfection treatment process that kills any remaining microorganisms that survive that other treatment and filtration process did not occur. I am advised that six megalitres of material was released from the plant. SA Water has implemented additional monitoring following the incident, and an investigation is now underway as to the exact cause of the incident.

A 200-metre section of the beach either side of the outlet pipe was temporarily closed to fishers and swimmers from Saturday. Affected areas were signposted. Water samples have been taken from the area and are being analysed. Initial results of faecal bacteria indicated very low levels of E. coli of one and zero for various points along the beach, 100 and 200 metres north of the diffuser, and E. coli of one and four for 100 and 200 metres south of the diffuser. Those are very low levels of E. coli. In fact, they are such levels that they can barely be monitored; nonetheless, as I say, it is best to be safe. Final results, as I said, showed very low levels of bacteria present.

The beach was reopened on Monday, following advice from SA Health. SA Health has advised that people coming into contact with undisinfected wastewater could experience gastrointestinal illness—that is, could—and that if people had come into contact with the water and developed an illness, they should contact their medical practitioner. That is always good advice.

The incident was controlled very quickly. It did not result in a potentially unsafe environment for beach users and therefore has caused, perhaps you could say, an inconvenience for people when they need not have been inconvenienced, but we did not know or have those results at the point in time when we decided to close the beach. I do prefer to take a course of action around safety first, and I think that is the correct course of action.

In terms of the honourable member's questions about remainders of water being redirected out to the gulf, that is the situation that will continue into the foreseeable future, but you may recall announcements in recent days about the Northern Adelaide Irrigation Scheme, which seeks to take a further 20 gigalitres—that is 20 gigalitres more—of water, eventually, out of the Bolivar wastewater system. That is on top of the 11 to 19 gigalitres of water that is currently utilised through the Virginia wastewater pipeline for irrigation. In the first instance, NAIS will utilise 10 gigalitres, with the potential to ramp it up to 20 at a later stage.

SA Water has been working assiduously to deal with the nutrient levels, and my understanding is, as I have said, that there has been a 75 per cent reduction in nitrogen in the wastewater that goes out to the gulf in South Australia. That is a massive reduction in terms of nitrogen.

The Hon. J.S.L. Dawkins: Massive.

The Hon. I.K. HUNTER: It is massive. It is 75 per cent. It is even bigger than the result that the President of France got in his election over the weekend. Nonetheless, we will continue to work on that. I understand that irrigators actually prefer to have the nitrogen left in because it is useful for crops, but we take the view that if we can reduce it then the water quality going out to the gulf is improved. Even if the amount of water going out to the gulf is reduced by those extra 10 to 20 gigalitres, nonetheless that is a worthwhile thing to do and SA Water will continue to invest in the infrastructure to do just that.

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