When I'm often asked when grease interceptors should be serviced, I wonder whether those who are asking have bigger concerns -- notably that increasing the pumping frequency of grease separators does not eliminate high FOG effluent numbers.
Tagged with 'pretreatment'
Testing your assumptions is always good as a pretreatment professional because so many variables impact your job. New technology and data can compel you to change some of your longest-held beliefs.
Is it possible to assume there are universally held “technical understandings” that solve nearly all fats/oils/grease issues? Are there other universally held “technical understandings” that are expected to solve TSS, BOD, pH, and other pretreatment/collection system issues? How did these “universally held technical understandings” come about and why are they still the tail that wags the proverbial dog?
This post questions a few of these universally long-held “technical understandings.”
The discourse at CWEA's annual conference was lively despite the virtual setting. Pretreatment professionals discussed ways they adapted during the Pandemic, while cities shared aggressive plans to expedite permitting processes and get commercial clients up and running again.
Hospitals and other health care facilities often operate extensive commercial kitchens. But unlike restaurants, hotels and other foodservice establishments, hospitals face additional cost-control, sanitation and operational challenges.
They have one or more commercial kitchens that may feed effluent into plumbing systems that run for hundreds or thousands of feet before exiting the building.
Hospitals also operate on a 24/7 basis, requiring them to keep downtime to a minimum. They don’t close for holidays, and their kitchens must keep operating matter what.
These factors mean that hospitals face unique pretreatment challenges. Facility managers and engineers must carefully consider their pretreatment technology, or risk high-cost repairs and even breakdowns that could threaten the health of patients and workers.
If you read our post on how emulsions can lead to fats, oil and grease (FOG) escaping a grease interceptor, you know that some grease will inevitably get into the wastewater system.
While the amount of grease getting through each day doesn’t seem that large, it constitutes what many feel is the greatest threat to the world’s sewer systems.
You might wonder why it would be a problem if the fats and oils have been emulsified — broken into tiny particles — through physical emulsion or, via soaps and detergents, chemical emulsion. And what that has to do with grease interceptor design.
Even if a commercial kitchen has an effective grease interceptor properly installed and maintained, fats, oils and grease (FOG) can still escape into the wastewater system.
While no grease removal system is 100 percent effective, a properly maintained, modern grease trap can still remove more than 99 percent of FOG found in kitchen effluent. One of the biggest obstacles to grease removal, though, is the invisible thief called emulsion.
Emulsion is a “fine dispersion of minute droplets of one liquid in another in which it is not soluble or miscible.” So what does that mean in plain English? And what can you do about it?
Across the country and around the world criminals are targeting a new kind of “liquid gold” — used cooking oil.
The headlines say it all:
“Three charged in Harford in $1 million scheme to steal used cooking oil”
“Huh? Thieves stealing used cooking grease to turn into quick cash”
“Theft of grease for biofuel gets stickier”
In 2014, two brothers, both in their 70s, pleaded guilty to federal charges of conspiring to sell and transport used cooking oil stolen from restaurants in Rhode Island and Massachusetts. The FBI wiretapped a federal informant to bring the pair to justice, and prosecutors said the two men stole grease worth more than $120,000 over the course of two years.
Businesses and local authorities, though, are fighting back.
One size fits all might be an appropriate term for a rain poncho. Or a baseball hat fitted with an elastic band. Perhaps even a baggy pair of sweatpants with a drawstring. But, the term has no place in the world of grease pretreatment.
For a pretreatment plan to be effective, the effluent rate of a commercial kitchen, along with its size and type of food served, must be considered.
The century-old technology that is the traditional concrete interceptor is still the go-to choice for many food service establishments, despite its numerous problems. These are viable for some facilities — if they have the space. But it’s just not practical for many others. Many establishments, such as strip mall restaurants or restaurants located inside office buildings or in tightly packed urban areas, don’t have the available outdoor space.
But there are other choices.
Organic and “natural” products and methods enjoy a glowing reputation in the marketplace. They’re able to command higher prices and for many people are a preferred choice when there is a choice.
They’ve made inroads beyond food, too, to products such as apparel (made with organically grown cotton), cosmetics and a variety of products constructed from “sustainable” recycled materials.
It’s not surprising, then, that restaurants and other commercial kitchen operators are interested in biological methods of pretreating grease-laden kitchen effluent. Beyond the attraction of a biologically based treatment system, these methods also hold out the possibility of minimizing pumping and other maintenance required by mechanical separation systems.
But while enzymatic and bacterial treatment solutions are growing in popularity, many questions and challenges remain.
Before considering enzymatic or bacterial solutions, there are a number of factors you need to consider.
The damage that grease and other pollutants can inflict on the environment is well documented, but few cases illustrate this as well as Narragansett Bay in Rhode Island.
Narragansett Bay is a prime example of what untreated sewage can do to the environment. However, it’s also a great case study in how pretreatment can help turn around polluted waterways and help reverse the impact of pollution.
The problem began in the 18th century when Rhode Islanders would empty their raw sewage directly into their nearby rivers that flowed into the bay. By the 1970s, nearly 65 million gallons of untreated sewage was flowing into Rhode Island’s waters each day. Grease deposits the size of soccer balls were sometimes seen floating in the bay. The bay’s shellfish beds, which had created a booming industry, were closed.