Long-time POWER readers may remember Marmaduke Surfaceblow, a fictional character whose engineering escapades were brilliantly portrayed in hundreds of stories published within POWER magazine’s pages over more than 30 years beginning in 1948. Today, the fictional series continues through Marmy’s granddaughter, Marnie, who is an engineering wiz in her own right.
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Regardless of what you think you know, when outside of your field of expertise, call for the experts.
Marnie Surfaceblow, vice president of Surfaceblow & Associates International, carefully wrapped the final turns of a bandage around the hand of her lead field engineer, Maya Sharma. Three Japanese-American women watched the process in silence. Maya turned to them and asked, “Misses Lily, Tae, and Sakura, do all of the animals on this farm, um, bite?”
Lily Hoshikawa laughed, while her sisters attempted not to. “Pretty much. On this farm, if it has teeth, it’ll bite. I apologize about Nacho biting you though—he is a rotten scoundrel, and I had no idea he’d choose your hand over the carrot you offered,” Lily said.
The second sister, Tae, admired Marnie’s first-aid work. “Marnie, you really missed your profession. You should have gone to medical school with the three of us.”
In This Issue
Full issue“And if you had,” added third sister Sakura, “then we could have kept our band together! Zetsubo¯ no Shimai forever!”
“I have heard Ms. Surfaceblow say that name before, but could not determine the meaning. What does the name of your former band translate as?”
“Sisters of Hopelessness,” replied Lily. “We were the best Goth group ever!”
“Um, we were Dark Cabaret sometimes,” retorted Sakura.
“Our Emo songs were hits—at least the ones I wrote were,” added Tae.
“Darkwave,” Marnie pronounced while stowing away the first-aid kit. “Sorry, sisters, but we don’t have time for reminiscing. There’s a bad ice storm coming, it’s December 23rd and I do not want to spend Christmas trapped in a ditch eating emergency rations until they dig us out. Give us the tour and tell us about your crazy anaerobic digesters.”
Healthy and Ecologically Friendly Opportunities
Lily told the story as they walked. “All three of us are physicians, specializing in internal medicine. We opened a joint practice, shared a house, traded shifts, and worked the system to help our patients and save money. One night around dinner we had an epiphany—almost half the digestive problems of our patients could be traced to milk products. Tae took a leave for post-doc research and found most milk sold in our city was tainted with herbicides, pesticides, and even heavy metals.”
Lily continued, “One night after re-watching The Breakfast Club for the hundredth time, we were inspired, and vowed to combine our money and brains to solve the problem at the source. Long story short, we created ‘Saga Sisters Organic Milk,’ named after our homeland of Saga Prefecture. We produce everything from whole to skim, chocolate of course, and this summer kicked off yogurt with our Framboises Fraîches offering—fresh raspberry!”
Marnie shook her head in amusement. “I guess I was most inspired by Weird Science, because I’ve seen and done some crazy things … but starting a business like you have at this cool old farm, it sounds really nice.”
Sakura chimed in: “Our milk and everything that goes in it is 100% organic. We test every feed truck, test and filter the water, and monitor indoor air quality constantly making sure the cows are happy—all 2,000 of them. We use no hormones, growth supplements, or anything else that could cause problems. We vaccinate them of course—we are physicians after all—and the cows have the finest medical care. And we’re making more money than ever.”
As they walked toward the digester building, Maya asked Lily, “I am curious, Ms. Hoshikawa, what inspired installing anaerobic digesters?”
“It was my idea,” Tae said, almost bouncing with excitement. “Having so many cows means we have a lot of manure. We used to have a huge pond that bubbled and stank and was just gross. And it released huge amounts of methane. One day I heard a story on NPR about anaerobic digesters for reducing animal waste, and so I started studying the technology.”
Marnie sighed with just a little pique. “If only you knew someone who was literally the world expert in energy and fuel-related engineering. If only.”
Lily put a hand on Marnie’s arm. “Hey, sis, no offense intended. We didn’t know what we were getting into, and the companies we talked to made it sound as simple as putting in a solar farm.”
“With respect, Miss Hoshikawa, creating even a small solar farm is not simple,” replied Maya, who received an approving nod from Marnie. “So, let us look at the system, and see its design. Do you have the original design and performance guarantee documents?”
The three sisters shared a somewhat embarrassed look. “Um … maybe? It might be in an e-mail folder … maybe?” responded Tae.
Marnie took one hand and clutched her head, as Maya added, “I see equipment brands I recognize, and I will attempt tracing the manufacturer’s specifications. Who was your licensed professional engineer that designed the system?”
“Um, we didn’t know we needed one, so I, um, did,” replied Tae, looking at Marnie with trepidation, which was well-deserved, as Marnie rounded on Tae with a full Scots fury that Maya had only witnessed once before. “Sisters, no! This is an anaerobic digester producing methane, carbon monoxide, and a host of other unholy miasmic and mephitic gases! This thing could explode, catch fire, suffocate you, or all of those things at once!”
Trying to appear hopefully humorous, Tae smiled broadly at Marnie. “Don’t worry sis, now we have you here to fix it!”
Risky Business
After Marnie had temporarily banished Tae from the digester shed to get hot drinks, she and Maya began cataloguing equipment and drawing a detailed process flow diagram (Figure 1). Sakura told the system’s story, as even though Tae had “designed” it, Sakura had done most of the grunt work.
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1. Marnie and Maya walked down the entire anaerobic digester system to verify flow paths and ensure the design was sound. Source: POWER |
“We started with one anaerobic digester as an experiment, and after 3 years it was making about 500 cubic meters per day of mixed gas from a quarter of our cow manure output, but also mixed food product waste, a little horse manure, and waste from the chicken coops. Barely 25% of the gas was methane, so at first, we burned the gas with a flare stack, but we were fined for doing that without a permit.”
“Flaring gas like that is still very dangerous. Forgive my temper, but the thought of you all being hurt, when you could have just called me …” Marnie paused. “So, what did you do then?”
“We studied more, talked to other digester owners, and installed continuous gas monitoring and alarms. We learned to stop mixing the chicken waste in, and our gas production and methane concentration increased, and with careful tuning we ended up at nearly two-thirds methane production.” Sakura paused. “Then, Lily had an idea,” she said.
“I found 10 whole-house natural gas generators on craigslist,” said Lily. “They didn’t produce their rated power due to the low methane concentration relative to natural gas, but we still can make almost 125 kW, if everything is working right. That’s enough to cover all our power needs.”
The door opened, and Tae arrived with hot tea and a flagon of coffee for Marnie, saying, “I made your special coffee for you, sis. Please don’t be mad at me anymore.”
“It’s … going to be OK, because Maya and I are here to help,” Marnie conceded. After several grateful swallows of coffee, she continued, “After having success with one digester, you added three more it seems. They’re very different than your first attempt, and I have to say they look better-made. And I admit, getting about two-thirds methane production is admirable from an amateur system like this. But from what you said in your call, the manure has officially gone sideways. Describe exactly what happened.”
The Vampire Slayer
“The problem with our first digester started right after we replaced the agitator. It seems the blade material wasn’t hard enough and the original one eroded badly. We couldn’t easily replace the blade, so we bought a more durable agitator with a much harder steel blade and installed it at the start of the year. It worked great and our gas production increased,” said Tae, pausing briefly to think. “But, then, before this summer, the generators it fed shut down one day. The monitors showed gas production was still high, but our methane level was less than 20%. We’ve been venting it since, and the methane level has decreased to about 5%, but our carbon dioxide is through the roof. So, I guess we’re putting out less methane, yay, but not getting any energy from the waste, boo.”
“Did you change anything else when changing the agitator?” asked Marnie. “The waste stream, the water concentration, the type of bacteria? And where exactly did you get this agitator? Did you make sure it was sterile before putting it back into the tank?” Marnie’s questions were rapid-fire, but her attitude had softened as she focused on the task at hand.
Tae responded, “It still exclusively uses waste from about 500 cows in our first barn. Water concentration dropped, but I kept it at the recommended levels by adding distilled water. We covered the area well and have been using high-power ultraviolet C-band—UV-C—lights to sterilize everything. The agitator came from an aerobic digestion farm that was shutting down its operations, but I placed the blade and shaft and everything into this sterilizer I made out of an old tanning bed. Here, let me show you!” Tae positively bounced as she led the group to a long polished wooden container, that looked like …
“You dressed up an old tanning bed as a coffin,” Marnie remarked, and then burst out laughing. “Oh, it’s absolutely perfect, Tae! And the irony is, I bet I know what’s inside!” Marnie opened the lid, and was so incapacitated by honest laughter from joy, she had to lean against Maya. The inside of the “coffin” was lined with high-intensity UV-C lighting.
“Hmmm. How many watts of light are in this container?” inquired Maya.
“About 3 kW of UV-C! It’ll roast any microbes to a crisp!” Tae happily replied.
Marnie howled with laughter. “Imagine, some poor vampire finds this coffin and crawls inside, only to be dusted in a microsecond … oh, poor creatures of the night! Woe be unto thee who stumble upon Lady Tae’s false promise of safety!”
At that point everyone, even Maya, couldn’t keep from laughing.
Digesting Information
Wiping tears from her eyes after seeing the humorous vampire and microbe-killing coffin, Marnie said, “OK, tell us about the next problem. You said you’re making way too much gas and too much methane from the other three digesters, right?”
“Yes,” said Sakura. “It started in early summer, just as digester one died. So, we can still power all our generators now by re-routing the gas, but we are making so much that it is slipping past the cover sheeting and we even tore a sheet open from too much gas pressure. We tried changing water concentration, reducing, then turning off, supplemental heating for the tanks. Nothing worked.”
“So, now we’re back to dumping half of our waste back in that awful manure pond, or ‘Satan’s Spooklight Swamp,’ as I call it, because of all the ghosts,” said Lily.
“What?!?” exclaimed Marnie and Maya in unison, recalling their ghost-busting adventure just two months prior.
“Oh, I have the coolest videos of it!” Tae squealed with joy as she grabbed her tablet computer. “There’s something different about the mixed waste, so every few days we see bioluminescent ghost lights!”
Marnie and Maya watched with amazement as Tae showed them several videos of lightly green-glowing bubbles rising from the manure pond at night, and even a couple of cases where large glowing blobs lifted several feet above the surface, drifting like a glowing lantern in the air before disappearing with a small flare and a muted “pop!”
Marnie sat down in a work chair and smiled to herself. “Well, I don’t know what’s made this trip better, Tae’s vampire-roasting coffin or creating your own official ghost swamp. Maybe we do need to get the band back together again and hold a giant dark music concert on your farm. Fans would come from around the globe to hear us play while ghost lights rose into the night. Hey, since it’s on a farm, can we call it Gothstock?” she asked.
Everyone smiled at the thought and the breaking of tension, as Maya, the diligent one, was going through the records. “Misses Hoshikawa, you said you still vaccinate your cows despite advertising as organic. Is that correct?”
“The U.S. Department of Agriculture allows vaccinations under their qualifications for being advertised as organic,” said Sakura. “And we’re already ahead of you here, methane production does spike after the annual tetracycline vaccinations. We may not be as smart as Marnie about some parts of science, but we are physicians. We use a low dose of vaccines and shift their feed composition a bit to reduce the impact on their gut flora, and typically the methane increase dies out after a couple of months. But this latest surge has gone nearly six months now, and all we can think of doing is building more digesters. But we really don’t want to—we aren’t in the power business—our goal was methane reduction.”
“Well, I’m glad you finally admitted that much,” said Marnie. Looking at Maya, she asked, “Do you see what happened with both defective digester cases, my apt apprentice?”
Maya frowned. “I believe I understand the methane over-production problem, but I will need more time with the case of digester one,” she said.
“Well, then,” said Marnie with a smile, “let’s go and get some warm drinks in your house, sisters, and relay a digest of our digester findings.” She was answered by a quartet of groans from the bad pun.
A White Christmas Filled with Cheer
The farmhouse kitchen was warmly cozy, and although Marnie and Maya had never visited before, it felt as comforting as home (Figure 2). Marnie grimly checked the weather forecast as the snow flurries were thickening. Braced with her hot drinks, Marnie and Maya compared notes from their inspection, and then Marnie said, “Maya, you worked out the second problem, so explain to our friends why three digesters are overproducing methane.”
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2. The Hoshikawa sisters’ kitchen had an industrial vibe to it with a coffee and tea bar suitable for commercial purposes. Marnie was in heaven! Source: POWER |
Maya nodded, then turned to the three sisters and said, “Framboises Fraîches. Misses Hoshikawa, you said you began to offer your organic fresh raspberry yogurt product this summer, and also that all food waste from the farm goes to the digesters, excepting digester one, which only takes the cow manure now. A digester, whether aerobic or anaerobic, is more than a machine—it is a living biological community. And if you change the bio-scape, you change how the microbes behave, or whether they can live at all. Food waste is highly rich in many nutrients, and fruit waste contains significant energy in sugars. Managing the quantity of higher-energy waste added to a digester is critical, and requires testing before you simply dump it in. I can refer you to technical papers discussing this.”
Surprised agreement and appreciation were shared among the sisters. Sakura asked, “Did adding the raspberry waste so close to our vaccination rounds cause this?”
“Perhaps,” Maya said uncertainly. “It may not be possible to know without many tests. However, the sudden bioluminescence in your waste pond is very uncommon, indicating you should test your raspberries for contamination with new, competing bacteria, especially those of marine origin—sometimes this can happen if seaweed is used as a fertilizer,” she noted.
Marnie nodded approval at Maya’s summary. “Now for digester one. Tae,”—Tae jumped at being addressed—“your UV-C coffin of death is truly inspired, I adore it! I really loved the little bat stickers you put on it too, nice touch. But you forgot one key fact—all that deadly UV-C light is impotent if it can’t reach its victims,” Marnie said.
“There could have been all sorts of competing microbes hiding in pits, deep scratches, in a bolt hole, or under a fitting. This is especially a problem given the new agitator came from an aerobic digester,” Marnie pointed out. “You all keep reminding me that you are physicians. Ever hear of this thing called autoclaving? You’re going to have to purge the digester, heat sterilize everything you can, and use chemicals for the rest. Then, transfer some bacteria from a reputable source, and you should be good once you reach critical mass.”
“Awwwwww!” replied Tae with an incredible pout. “First, you two are going to take away our cool spooky glowing swamp, and now my coffin of death will be useless! You’re no fun!” Everyone laughed, and all four members of Zetsubo¯ no Shimai started reminiscing about the good old days of their band, the gigs they played, and life in general.
As the conversation continued, Maya received a notification on her phone, raised her hand, and, with some trepidation, said, “Excuse me, all, they have just closed the roads until further notice.”
Their hostesses were overjoyed. “You both get to spend Christmas with us! We have a spare bedroom for you, super-reliable internet, tons of food, and best of all, our own music studio. And, Marnie, we still have all our old instruments, including your synthesizers and that ancient Hammond B3 you left behind.”
Incredulously, Marnie said, “But my family gave them away when I left!”
“They did … to us,” replied Lily. “They’re waiting for you in our home studio.”
Happy among her four friends, old and new, Marnie was teary-eyed. While Tae and Lily played the band’s greatest hit for Maya, “Homeroom Horrorshow,” Sakura quietly asked Marnie, “So, you’re going to give us all this work you and Maya did for free, right?”
After sniffling and blowing her nose, Marnie replied, “Not a chance. After all, you are physicians.”
—Una Nowling, PE is an adjunct professor of mechanical engineering at the University of Missouri-Kansas City.
