Exclusive: Secret report suggests fats, oils and grease accumulate in ‘inaccessible dead zone’ at Malabar plant, then dislodge when pumping pressure ‘rapidly increases’

A giant fatberg, potentially the size of four Sydney buses, within Sydney Water’s Malabar deepwater ocean sewer has been identified as the likely source of the debris balls that washed up on Sydney beaches a year ago.

Sydney Water isn’t sure exactly how big the fatberg is because it can’t easily access where it has accumulated.

Fixing the problem would require shutting down the outfall – which reaches 2.3km offshore – for maintenance and diverting sewage to “cliff face discharge”, which would close Sydney’s beaches “for months”, a secret report obtained by Guardian Australia states.

“The working hypothesis is FOG [fats, oils and grease] accumulation in an inaccessible dead zone between the Malabar bulkhead door and the decline tunnel has potentially led to sloughing events, releasing debris balls,” the report concludes.

“This chamber was not designed for routine maintenance and can only be accessed by taking the DOOF offline and diverting effluent to the cliff face for an extended period (months), which would close Sydney beaches.”

    • HellsBelle@sh.itjust.worksOPEnglish
      76·
      2 months ago

      Yeah. We are an arrogant, fucked up species.

      Unlike most cities, Sydney only does primary treatment of its sewage – straining out the solids. Elsewhere, secondary treatment uses settlement tanks and disinfection techniques before releasing the wastewater or recycling it.

      Singapore, for example, treats its sewage to such a high level that it can be reused in the drinking water system.

      • i_stole_ur_taco@lemmy.caEnglish
        28·
        2 months ago

        I did a sewage treatment plant tour in my high school biology class. At the end of the second stage filtration, the worker pointed at how it discharges into the ocean.

        “So at this point, the water has been treated enough that it’s safe to drink”

        We all scrunched our faces at that. Then he added

        “But I wouldn’t”

        • fishos@lemmy.worldBannedEnglish
          8·
          2 months ago

          You would be amazed how often “the solution to pollution is dilution”. Can’t dump that raw chemical into the water/sewer, oh no. But if you dilute it with 5000 gallons of water? Oh well now it’s at “acceptable levels”. Notice how most regulations talk about “parts per million”(PPM). Well, it turns out that when most of your regulations are written such that you only have to “properly dispose” of something if it’s above a certain concentration, you can just dilute it below that level and BAM, “safe to dispose of”.

      • ms.lane@lemmy.worldEnglish
        21·
        2 months ago

        Singapore

        Nice that the article is trying to make it sound like such solutions are from ‘other countries’

        Meanwhile, we have full treatment in South Australia and the outflow water is used for watering gardens.

      • Railcar8095@lemmy.worldEnglish
        6·
        2 months ago

        This is highly misleading. Even if you can get drinking water out of sewage, most of it is disposed somewhere. Sidney might be doing a shit (pun intended) process, but there’s no magic way too turn it all into water.

        • SpongyAneurysm@feddit.orgEnglish
          2·
          2 months ago

          Citation needed.

          I highly doubt that. There would be absolutely no reason to clean the water up to tap water quality and then discharge it into the river, instead of using it as tap water. That’s just not economically feasible.

          I know a part of the Danube near Vienna is a valuable nature reserve, but even then tap water quality is not necessary.

          If you have a source that proves your claim, I’d be highly interested to learn why and how they do that. I have a degree in environmental engineering, and I want to know when I’m wrong about something like this.