Alan Dickens, Brunswick Heads
Byron Water and Recyling (W&R) have been in denial since 2002 that infiltration in Mullumbimby gravity mains is coming from deep infiltration.
The methodology I have always applied is infiltration is caused by rain; once the rain stops the main supply of infiltration stops so sewer pumps should return to dry-weather run hours quite quickly. But they do not; the pumps take weeks longer in heavy rain periods to return to dry-weather run hours. I consider this the result of deep infiltration, not shallow or surface infiltration.
As a former member of the Waste Water Advisory Committee (WWAC) I’ve asked three companies specialising in Vacuum and Low Pressure Pump Systems (LPPS) to give me prices on fitting the two systems in Mullumbimby.
The middle price I have received is: Vacuum $15,000 to $18,000 per house, approximately $18 million compared to LPPS at $25,000 per house, equating to $25 million.
LPPS is placed on the homeowner’s property and connected to the homeowner’s power supply. Maintenance cost are quite high.
Vacuum System is placed on Council land, a pod every four houses, no power required to the pods, substantially lower maintenance costs than LPPS.
I did raise this in a Waste Water Sewer Advisory Committee meeting as to the price of a vacuum system and was told they had done their own modelling and it had come in at $40 million. I asked to see this modelling; it was never produced.
Maintenance costs for the LLPS at New Brighton supplied by Byron Shire Council’s Director of Infrastructure (DI) for planned maintenance (PM) and reactive maintenance (RM) are 2015: PM $24,851,79, RM $52,497,31; 2018: PM $27,592,76; RM $132,662,55.
The DI also supplied LP pump replacement numbers from 2004 until 2008. There have been 228 pumps repaired or replaced in New Brighton out of 240. Having asked this question in the WWSAC in 2018, the answer was four.
The Director of Infrastructure says nothing has been decided yet, but this is not the way I interpret what I read, supposedly endorsed by the WWSAC, which went to the elected council after the May 31 meeting of the WWSAC. I argued against this as did other members; no vote was taken on this trial issue.
To spend this amount of money is not a trial, it is ignoring the facts on infiltration.
Council does have a policy 12/014 that favours LPPS, but clause 4.1.C states other systems better suited for the application required should be considered.