For generations, a family business has operated on a slice of farmland in north-west Sydney doing a smelly but essential job.

Bush's Protein Plant at Rouse Hill collected all red meat waste from butchers across Greater Sydney and parts of NSW for use in products like pet food.

But over the decades, suburbs like Grantham Farm and Tallawong sprung up around the plant, with Box Hill's Nelson Estate is just 700 metres away. 

According to the NSW Environmental Protection Authority (EPA), as these suburbs have developed there has been an increase in odour complaints about the plant from members of the community.

Cameron Bush is the head of rendering at AJ Bush and Sons and last month made the "absolutely, terribly difficult" to cease operations within weeks and appropriately decommission the site.

Red meat by-product cannot be sold or disposed of in landfill due to the risk of hazardous bacteria, but can instead be used for pet food, cosmetics, greases and, more recently, biofuels.

The company's integrated service at Rouse Hill meant all by-product was collected free of charge from butcher stores and rendered at the protein recovery plant.

Mr Bush, whose grandfather established the plant in 1956, said the plant offered a "unique" business model, so demand was consistently high.

"Up until recently, we were servicing around about 1,000 collections every week," Mr Bush said.

"The ability for us to render the product and allow us to recover those fats and oils enabled us to provide the service free of charge to butchers of the area."

Encroaching suburbia puts factory under pressure

Mr Bush said they never used to be able to see houses from the plant but now they were "everywhere".

"We've invested a lot of money into odour control with the understanding that the community is here," Mr Bush said.

"We've also tried to educate the community around the service we provide and how critical it is for collecting the fat and bone."

While on site in September, EPA officers identified several areas where there were spills or leaks from equipment and issued the company a $15,000 infringement notice.

"We committed … to find[ing] alternative methods [of] collection and handling. We went through that process and unfortunately, we could not make any value stack up," Mr Bush said.

"We were losing about $100,000 a week."

More bills, higher prices

During his 12-year career as a butcher, Chris Boyd-Skinner hasn't had to worry about the disposal of red meat by-product from his store at Blackheath, in the Blue Mountains.

"It didn't cost us anything. [AJ Bush and Sons] would just come pick it up and that was it," he said.

With Bush's Protein now closed, Mr Boyd-Skinner said he will have to use another waste management service – some of which have quoted him up to 40 cents per kilogram of by-product.

On average, his store generates 60kg of by-product each week, and said he's going to "try and use everything [he] can" to reduce the new bill.

"[It will] probably affect us more in the summertime when the flies and the bees hang out around the back cause it's got to go out the back."

'We can't let protein waste come here'

Earlier this month, Blue Mountains councillors moved an urgent motion to reassure residents the often odorous by-product would not be accepted by Blaxland Waste Management Facility.

Councillor Roza Sage said there was "a lot of confusion" among local butchers as to who is responsible for collection and where it should be deposited.

"Some of them might put it into general waste and we don't accept protein waste into the facility," she said.

"What [could] that do? There's going to be smell issues … and an increased number of vermin too."

A spokesperson from the NSW EPA said landfill operators, such as councils, have the right to set what types of waste they will and won't receive. 

"Meat or animal waste can decompose quickly and pose a risk to human health and the environment, so it must either be reused through rendering or disposed of at a landfill that can accept putrescible waste." 

Cr Sage said she's sympathetic to local businesses who must now manage "extra charges on top of all the cost-of-living increases, especially with their electricity and refrigeration".

“We are part of the Sydney Basin, so this closure affects businesses in our area too,” she said.

The council said it would consult with higher levels of government to find a solution, however Cr Sage said she would ultimately like to see the Bush's Protein plant relocated.

Mr Bush agreed but countered that "relocating is not an overnight option".

No similar alternatives

Australian Meat Industry Council (AMIC) CEO Patrick Henderson said the loss of Riverstone's "exceptionally specific" business model would rattle the sector.

He said all 300 members of AMIC are among those affected by the closure of Bush's Protein. 

"We don't have another business like that. They're all a little bit more disjointed and that's why it comes at a cost," Mr Henderson said.

"It just shows how sustainable the meat industry is in this country because we are taking that product and its being turned into things such as biofuels."

According to AMIC, up to 30,000 tonnes of red meat by-product is generated each year by NSW butchers.

Mr Henderson said the industry body was limited in its ability to offer replacement services.

"It's all in the realm of commercial decision-making so nothing that the industry body or anyone else can do, or say, to change that.

"So, there will be some short-term pain as we work through this."