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.”
I work in the field and some units can in fact produce enough gas to self sustain operation. It is about choosing the right process and the adequate machinery.
Newer systems, with SBRs, do tend to produce a lot less muds. Older systems, like the one I spend more time on, produces a great deal more of muds.
A midsize city around where I live is currently undergoing viability studies to implement a digestor. They are trucking off-site 30 metric tons of dehydrated muds for composting every two or three days. If the muds could be digested first, they could cut back a good deal on the energy bill.
Other places are installing solar panel arrays and considering batteries next.
Do you mind sharing which part of the world you’re in?
I made my degree in Germany (and Switzerland for a small part) and there are a few assumptions that come with that. We mostly have combined sewers here (i.e. wastewater and rainwater runoff through the same pipe) and local regulations of course.
Maybe you have different circumstances where you live?
Also on a side note: I consider solar panels as a kind of a cheat as well, because they are not in any way reliant on the water treatment process and could be installed regardless and fed into the grid. Though the dual usage of the area is much appreciated and using their energy at the source is a good idea.
Hello from Portugal!
We also suffer from combination of rain and waste waters here. And most cities just wave it off, even when solving the problem could be done with very little inconvenience.
But I digress.
What type of installation are you more familiar with?
Most instalations around here are two stage processes, fully biological. Exceptions with terciary processing are very few and with fourth stage processing I have heard about a single one, that once supplied water to a brewery for a proof-of-concept experiment with crafting beer with processed waste water.
I respect your remark. The solar panels are not technically a part of the process but we can agree the use of otherwise vacant space is smart.