Waste by the wayside: Treatment plant process undergoing improvements, aiming for even smoother operation

Mar. 1—ASHLAND — Jeff McFarlin, an operator at Ashland's Wastewater Treatment Plant, strikes a bit of a philosophical tone while standing next to a pool of sewage.

"If you look at history, every great society has figured some way to get water and some way to get rid of the waste," McFarlin said. "It's just a necessity."

Some societies were better at it than others — the Romans set up sewer systems made of stone, similar to what we see today. Nineteenth century Londoners dumped their bile in the Thames, leading to cholera outbreaks. In the Middle Ages, sloshing a pail of crap onto the street was commonplace.

Wastewater treatment is a bit more advanced in Ashland than, say, 15th Century France; however, as utility director Mark Hall noted, the system is definitely aged.

"You know how in Cuba they drive cars from the 1950s and the 1940s and keep them running?" Hall said. "That's pretty much what we've done with the sewage plant."

Hall should know — prior to taking the Utilities Director job with the City, he ran the Wastewater Treatment Plant.

The current version of the plant has been in operation since 1981 — the industry standard, according to Hall, is 20-25 years of service. Despite the aged technology — McFarlin and plant superintendent James Morgan joke that the high-tech computer control system is a series of handles and widgets to manually turn — the plant is still putting out some high-quality H20 into the Ohio River.

According to Hall, the EPA standard for capturing waste from the water is 85% — however, the city has set a standard at 92% in agreement with the EPA, a standard Hall said is typically exceeded.

In fact, the plant was recognized last year by the Clean Water Professionals of Kentucky and Tennessee for having one of the shortest lists of violations for that year. Only seven other plants in the commonwealth have earned that distinction.

Not bad for keeping the equivalent of Studebaker on the road.

Like all areas of the "four-headed beast of public utilities," as City Manager Mike Graese calls it, the plant is due for some upgrades and expansions.

City Engineer Steve Cole said the plant is on deck for a full-scale renovation.

"This is going to be a full gut and remodel to the house," Cole said.

Right now, the city is in the design process — which got pushed back a little bit due to COVID-19 preventing travel to various plants to see what's working and what's not. However, with a bit of wiggle room already built into the schedule, city officials have said they should be able to meet a 2025 deadline for the update set by the EPA.

Sewage: More than what you think

Before getting into the nitty-gritty of how the plant turns black water clear, a few words need to be said about the water before it gets to the plant.

According to Cole, when the plant was first designed, the idea was for it be a regional plant, serving more than just the Ashland sewer system. While no one likes or wants the job loses in seen in the region, the depopulation over the years has helped prolong the life of the plant, according to Cole.

"It's a benefit that's less than desirable," Cole said. "We've lost the Coke Plant, we've lost AC Lawrence Leather, we've had all these major employers go out of business and we certainly don't want that. But because those flows are reduced and we're absent those sources, it has helped to extend the mechanical life of the plant."

Right now, the plant processes sewage for Ashland, Boyd County Sanitation District 4, which extends to each park and leech water from the dump.

Think of it like your school shoes — remember when your parents would buy a size or two up, so you'd grow into them? They'd last a lot longer then buying right on the size — that's what's happened with the plant. It can accommodate more than it's getting, most of the time.

"Heavy rain events are what leads to overflow and overwhelming the system," Morgan said.

See, that's because Ashland has a combined sewer system — No. 1, No. 2 and rains end up in the same pipes heading to the plant. Now, unless there's a mass break out of the runs in the city, generally speaking the sewage remains steady and is treated at nearly 100% by the plant. But rainwater — especially after a good gully washer — can surge the system, causing the plant to overflow into the river.

That's what drags the numbers down a little bit in terms of water being treated, according to Hall.

Graese said there have been some improvements on the front-end of the system — he pointed to the 29th Street project back in 2017 as a game changer in the how the city does its sewage.

"This was a massive inconvenience to our cities and there was a lot of misinformation out there on the timeline, but ultimately this has become a benefit to our citizens," Graese said. "What the city did in that project was separate the storm water from the wastewater."

By separating storm water and waste water — the professional term for your morning constitution — up to 4 million gallons of rain water during a rain event have been recorded as diverted from the plant straight into the river, according to Graese.

During an average rain, city officials estimated roughly 2 million gallons of rainwater is diverted from the plant thanks to the improvement.

Cole said the city is still operating as a combined sewer, but diverting more rain water and improving collections as much as feasible ahead of the improvements to the treatment plant is the right approach.

"We've seen a lot of communities update treatment and not focus on the collection infrastructure," Cole said. "That has led to problems down the road when there's changes in the city."

Hall said it seemed a bit backwards to him — admittedly a bias on his part due to his tour of duty at the plant — but in retrospect it was the right move to prolong the plant's life and optimize its performance once the improvements and renovations are made.

Grit and Clarity

Walking through the process of waste water treatment is both incredibly complicated and incredibly simple.

What it boils down to, according to Morgan, is removing solids from the water before treating it and releasing it into the river.

Throughout that process, water that isn't quite cleaned is recycled back into the system — much like running more 'shine through a still to improve its purity.

Which is funny, considering at certain stages in the process the waste water is called "black liquor," Morgan said.

At the start of the system is the in-flow trough, which is pumped up from a nearby station and has a tap for trucks from the dump to inject leech water into the system. Black and frothy, the water first enters two grit basins, which are large pools with a blade going to the bottom.

In the side of the pool is a hole, which is connected to a trough on the other side. As the blade inside the basin turns, the grit — egg shells, sand, gravel, etc. — is pushed into the trough. Inside that trough is a screw, which elevates up and out — the gritty water moves up the screw, gradually losing water until it's nothing but solids.

Much like a grain elevator, the solids steadily flow out the end of the screw and into a dumpster.

From the grit basin, the water is sent to the carousel, which is a large pool of water in an S-curve shape where a certain amount of sludge is retained in order for certain microorganism to feed on materials and waste. At the bottom of it is a blade that keeps the water moving.

Morgan said it's a delicate balance in the carousel — they need to achieve 3,000 parts per million in the water to get sufficient feeding. Too much and the water is too solid for treatment down the line. Too little and the water is too thin and the solids aren't being treated enough.

Working off gravity, the water from the carousel spills over the side into a pipe running underground, which is then pumped into the clarifiers, four rectangular pools side by-side, with two troughs between them.

Feeding the clarifiers is another balancing act for plant operators, according to McFarlin. Pointing to a T-tool leaned against the side of the wall, he said operators must manually regulate the flows so as to not overwhelm that stage of the system.

The water is pumped up into the clarifier, where — via a winch — a blade and a stainless steel tube pushes back and forth along the pools. It almost looks likes a spreader on a farmer's field. However, instead of spreading, the device is separating.

The water is being pushed into the troughs between the pools, which go on for treatment. The sludge, which has settled at the bottom, is being sucked up to go onto the thickener, for further processing.

Once out of the clarifier, the water goes to the chlorine tank to further kill any biological organisms in the water, Morgan said. Then the water is run through another pool, where another chemical is added to cancel out the chlorine.

After falling down a waterfall to turn up the water one last time, the now clean and clear water — clean enough to drink, if one is as brave as McFarlin — is shot out into the river.

The thickener is similar to the grit basin — a blade turning to get the sludge to coagulate before it goes on to the filter press building. Like any stage in the system, water is drained from the thickener and sent into a return to be put at the head of the system.

Instead the filter press building, Cole said a machine "like grandma's old ringer washer" presses the sludge through a series of belts, removing was much water as possible before being shot into a dumpster.

Of course, in the middle of this system is a laboratory and sampling areas for the plant to run tests to make sure everything is in compliance and no harmful chemicals make it into the Ohio. Morgan and McFarlin said about 95% of the compliance tests are done in-house.

So how long does it take? According to Hall, on average, water is retained for two days from entering the system to leaving it. Sludge is on a 28-day retention period from entering before ending up at the land fill.

From Old to Gold

During the pre-engineering design phase, city and plant officials have toured six plants in Kentucky and Indiana to "see the difference between gold-plated and just getting by," according to Graese.

Part of that process involved some test driving on new equipment, such as a centrifuge and screw presses for sludge processing.

As it stands right now, the current filter press is about to make sludge about 17% dry, according to McFarlin. A screw press, which Cole likened to "grandma's old meat grinder," can make get that sludge approaching 30% dry. A centrifuge tumbles the sludge about, like grandma's dryer, taking more moisture out of the sludge.

What does this mean to the tax payer? Hall said less moisture means less weight at the dump, which means it costs less to unload the sludge.

That's just one of many new improvements being looked for the plant, Morgan said. Automation of processes is another huge hurdle at the plant — right now, the electronic controls look like something from a 1960s space movie, with a patchwork of digital displays thrown in for good measure.

Disinfection is another area needing attention — Morgan said the EPA is trying to move plants away from chlorine, which is fine by him due to the danger of the handling the product.

Cole said the foot print of the plant is also on the table . He said the city is working to acquire adjacent property so the plant can be larger. Hall said when he was first hired in, the old timers on the job used to refer to the building where the filter press is located as the "old plant."

"Before long, that's going to be the old-old plant," Hall said.

Pressing the plant ahead into the second-decade of the 21st Century is also paramount for attracting large employers and industry, Graese said.

"Any company that is coming to this area wants to look at infrastructure to see if we can handle whatever they're plugging into the system," Graese said. "This includes how we treat our wastewater. As we expand on this, I think industry will see we can handle their output."

(606) 326-2653 — henry@dailyindependent.com