The proposal is to close Ocean Shores Sewage Treatment Plant (OS STP) and transfer its load to Brunswick Valley STP (BV STP), a centralised facility built 15 years ago to replace Mullumbimby and Brunswick Heads STPs built in the 1960s. OS STP was built 30 years ago and is in need of repair or replacement.
BV STP has capacity in dry weather for OS flows, but not in wet weather. So the proposal included what is politely called a ‘Balancing Pond’ at the BV STP. Because our sewer systems leak stormwater into them in heavy rainfall periods, the BV STP is too small to treat combined wet weather flows from OS and BV. Excess sewage would be stored in the new ‘Pond’. When the storm period ends and daily sewage production eventually drops back below BV STP’s capacity, the ‘Pond’ contents would be treated. That’s called ‘Balancing’.
Council’s Water Sewer & Waste Committee, of which I’m a member, met on 30 September and resolved a hybrid strategy instead for the two STPs but without the Balancing Pond. We don’t believe untreated sewage should sit around for days in an open pond. And it isn’t ‘best practice’.
The Committee agrees with the transfer pipeline but wants the asset of OS STP retained and repaired, to handle flows up to its wet weather capacity of say eight megalitres per day. It currently receives peak inflows way above that.
The hybrid solution makes economic sense but there are other factors as well. The BV STP was approved on the basis of an Estuary Management Strategy (EMS) which indicated 20 years ago that the Brunswick River would cope with discharges from OS and BV STPs. The EMS must now be
updated for the new proposal, because it shifts STP discharge from one part of the estuary to another. People flushing their toilets in town want to know they are not buggering up our river (the so-called ‘receiving environment’).
Council must also focus, as the Committee has said for decades, on getting STP discharges out of the river. This is easily done by re-using treated effluent for irrigation or to replace fresh water for urban consumption, most of which is not used for human ingestion. It’s called closing the loop, a basic principle of environmental management.