[Note that this article is a transcript of the video embedded above.] Wichita Falls, Texas, went through the worst drought in its history in 2011 and 2012. For two years in a row, the area saw its average annual rainfall roughly cut in half, decimating the levels in the three reservoirs used for the city’s water supply. Looking ahead, the city realized that if the hot, dry weather continued, they would be completely out of water by 2015. Three years sounds like a long runway, but when it comes to major public infrastructure projects, it might as well be overnight. Between permitting, funding, design, and construction, three years barely gets you to the starting line. So the city started looking for other options. And they realized there was one source of water nearby that was just being wasted - millions of gallons per day just being flushed down the Wichita River. I’m sure you can guess where I’m going with this. It was the effluent from their sewage treatment plant. The city asked the state regulators if they could try something that had never been done before at such a scale: take the discharge pipe from the wastewater treatment plant and run it directly into the purification plant that produces most of the city’s drinking water. And the state said no. So they did some more research and testing and asked again. By then, the situation had become an emergency. This time, the state said yes. And what happened next would completely change the way cities think about water. I’m Grady and this is Practical Engineering. You know what they say, wastewater happens. It wasn’t that long ago that raw sewage was simply routed into rivers, streams, or the ocean to be carried away. Thankfully, environmental regulations put a stop to that, or at least significantly curbed the amount of wastewater being set loose without treatment. Wastewater plants across the world do a pretty good job of removing pollutants these days. In fact, I have a series of videos that go through some of the major processes if you want to dive deeper after this. In most places, the permits that allow these plants to discharge set strict limits on contaminants like organics, suspended solids, nutrients, and bacteria. And in most cases, they’re individualized. The permit limits are based on where the effluent will go, how that water body is used, and how well it can tolerate added nutrients or pollutants. And here’s where you start to see the issue with reusing that water: “clean enough” is a sliding scale. Depending on how water is going to be used or what or who it’s going to interact with, our standards for cleanliness vary. If you have a dog, you probably know this. They should drink clean water, but a few sips of a mud puddle in a dirty street, and they’re usually just fine. For you, that might be a trip to the hospital. Natural systems can tolerate a pretty wide range of water quality, but when it comes to drinking water for humans, it should be VERY clean. So the easiest way to recycle treated wastewater is to use it in ways that don’t involve people. That idea’s been around for a while. A lot of wastewater treatment plants apply effluent to land as a disposal method, avoiding the need for discharge to a natural water body. Water soaks into the ground, kind of like a giant septic system. But that comes with some challenges. It only works if you’ve got a lot of land with no public access, and a way to keep the spray from drifting into neighboring properties. Easy at a small scale, but for larger plants, it just isn’t practical engineering. Plus, the only benefits a utility gets from the effluent are some groundwater recharge and maybe a few hay harvests per season. So, why not send the effluent to someone else who can actually put it to beneficial use? If only it were that simple. As soon as a utility starts supplying water to someone else, things get complicated because you lose a lot of control over how the effluent is used. Once it's out of your hands, so to speak, it’s a lot harder to make sure it doesn’t end up somewhere it shouldn’t, like someone’s mouth. So, naturally, the permitting requirements become stricter. Treatment processes get more complicated and expensive. You need regular monitoring, sampling, and laboratory testing. In many places in the world, reclaimed water runs in purple pipes so that someone doesn’t inadvertently connect to the lines thinking they’re potable water. In many cases, you need an agreement in place with the end user, making sure they’re putting up signs, fences, and other means of keeping people from drinking the water. And then you need to plan for emergencies - what to do if a pipe breaks, if the effluent quality falls below the standards, or if a cross-connection is made accidentally. It’s a lot of work - time, effort, and cost - to do it safely and follow the rules. And those costs have to be weighed against the savings that reusing water creates. In places that get a lot of rain or snow, it’s usually not worth it. But in many US states, particularly those in the southwest, this is a major strategy to reduce the demand on fresh water supplies. Think about all the things we use water for where its cleanliness isn’t that important. Irrigation is a big one - crops, pastures, parks, highway landscaping, cemeteries - but that’s not all. Power plants use huge amounts of water for cooling. Street sweeping, dust control. In nearly the entire developed world, we use drinking-quality water to flush toilets! You can see where there might be cases where it makes good sense to reclaim wastewater, and despite all the extra challenges, its use is fairly widespread. One of the first plants was built in 1926 at Grand Canyon Village which supplied reclaimed water to a power plant and for use in steam locomotives. Today, these systems can be massive, with miles and miles of purple pipes run entirely separate from the freshwater piping. I’ve talked about this a bit on the channel before. I used to live near a pair of water towers in San Antonio that were at two different heights above ground. That just didn’t make any sense until I realized they weren’t connected; one of them was for the reclaimed water system that didn’t need as much pressure in the lines. Places like Phoenix, Austin, San Antonio, Orange County, Irvine, and Tampa all have major water reclamation programs. And it’s not just a US thing. Abu Dhabi, Beijing, and Tel Aviv all have infrastructure to make beneficial use of treated municipal wastewater, just to name a few. Because of the extra treatment and requirements, many places put reclaimed water in categories based on how it gets used. The higher the risk of human contact, the tighter the pollutant limits get. For example, if a utility is just selling effluent to farmers, ranchers, or for use in construction, exposure to the public is minimal. Disinfecting the effluent with UV or chlorine may be enough to meet requirements. And often that’s something that can be added pretty simply to an existing plant. But many reclaimed water users are things like golf courses, schoolyards, sports fields, and industrial cooling towers, where people are more likely to be exposed. In those cases, you often need a sewage plant specifically designed for the purpose or at least major upgrades to include what the pros call tertiary treatment processes - ways to target pollutants we usually don’t worry about and improve the removal rates of the ones we do. These can include filters to remove suspended solids, chemicals that bind to nutrients, and stronger disinfection to more effectively kill pathogens. This creates a conundrum, though. In many cases, we treat wastewater effluent to higher standards than we normally would in order to reclaim it, but only for nonpotable uses, with strict regulations about human contact. But if it’s not being reclaimed, the quality standards are lower, and we send it downstream. If you know how rivers work, you probably see the inconsistency here. Because in many places, down the river, is the next city with its water purification plant whose intakes, in effect, reclaim that treated sewage from the people upstream. This isn’t theoretical - it’s just the reality of how humans interact with the water cycle. We’ve struggled with the problems it causes for ages. In 1906, Missouri sued Illinois in the Supreme Court when Chicago reversed their river, redirecting its water (and all the city’s sewage) toward the Mississippi River. If you live in Houston, I hate to break it to you, but a big portion of your drinking water comes from the flushes and showers in Dallas. There have been times when wastewater effluent makes up half of the flow in the Trinity River. But the question is: if they can do it, why can’t we? If our wastewater effluent is already being reused by the city downstream to purify into drinking water, why can’t we just keep the effluent for ourselves and do the same thing? And the answer again is complicated. It starts with what’s called an environmental buffer. Natural systems offer time to detect failures, dilute contaminants, and even clean the water a bit—sunlight disinfects, bacteria consume organic matter. That’s the big difference in one city, in effect, reclaiming water from another upstream. There’s nature in between. So a lot of water reclamation systems, called indirect potable reuse, do the same thing: you discharge the effluent into a river, lake, or aquifer, then pull it out again later for purification into drinking water. By then, it’s been diluted and treated somewhat by the natural systems. Direct potable reuse projects skip the buffer and pipe straight from one treatment plant to the next. There’s no margin for error provided by the environmental buffer. So, you have to engineer those same protections into the system: real-time monitoring, alarms, automatic shutdowns, and redundant treatment processes. Then there’s the issue of contaminants of emerging concern: pharmaceuticals, PFAS [P-FAS], personal care products - things that pass through people or households and end up in wastewater in tiny amounts. Individually, they’re in parts per billion or trillion. But when you close the loop and reuse water over and over, those trace compounds can accumulate. Many of these aren’t regulated because they’ve never reached concentrations high enough to cause concern, or there just isn’t enough knowledge about their effects yet. That’s slowly changing, and it presents a big challenge for reuse projects. They can be dealt with at the source by regulating consumer products, encouraging proper disposal of pharmaceuticals (instead of flushing them), and imposing pretreatment requirements for industries. It can also happen at the treatment plant with advanced technologies like reverse osmosis, activated carbon, advanced oxidation, and bio-reactors that break down micro-contaminants. Either way, it adds cost and complexity to a reuse program. But really, the biggest problem with wastewater reuse isn’t technical - it’s psychological. The so-called “yuck factor” is real. People don’t want to drink sewage. Indirect reuse projects have a big benefit here. With some nature in between, it’s not just treated wastewater; it’s a natural source of water with treated wastewater in it. It’s kind of a story we tell ourselves, but we lose the benefit of that with direct reuse: Knowing your water came from a toilet—even if it’s been purified beyond drinking water standards—makes people uneasy. You might not think about it, but turning the tap on, putting that water in a glass, and taking a drink is an enormous act of trust. Most of us don’t understand water treatment and how it happens at a city scale. So that trust that it’s safe to drink largely comes from seeing other people do it and past experience of doing it over and over and not getting sick. The issue is that, when you add one bit of knowledge to that relative void of understanding - this water came directly from sewage - it throws that trust off balance. It forces you not to rely not on past experience but on the people and processes in place, most of which you don’t understand deeply, and generally none of which you can actually see. It’s not as simple as just revulsion. It shakes up your entire belief system. And there’s no engineering fix for that. Especially for direct potable reuse, public trust is critical. So on top of the infrastructure, these programs also involve major public awareness campaigns. Utilities have to put themselves out there, gather feedback, respond to questions, be empathetic to a community’s values, and try to help people understand how we ensure water quality, no matter what the source is. But also, like I said, a lot of that trust comes from past experience. Not everyone can be an environmental engineer or licensed treatment plant operator. And let’s be honest - utilities can’t reach everyone. How many public meetings about water treatment have you ever attended? So, in many places, that trust is just going to have to be built by doing it right, doing it well, and doing it for a long time. But, someone has to be first. In the U.S., at least on the city scale, that drinking water guinea pig was Wichita Falls. They launched a massive outreach campaign, invited experts for tours, and worked to build public support. But at the end of the day, they didn’t really have a choice. The drought really was that severe. They spent nearly four years under intense water restrictions. Usage dropped to a third of normal demand, but it still wasn’t enough. So, in collaboration with state regulators, they designed an emergency direct potable reuse system. They literally helped write the rules as they went, since no one had ever done it before. After two months of testing and verification, they turned on the system in July 2014. It made national headlines. The project ran for exactly one year. Then, in 2015, a massive flood ended the drought and filled the reservoirs in just three weeks. The emergency system was always meant to be temporary. Water essentially went through three treatment plants: the wastewater plant, a reverse osmosis plant, and then the regular water purification plant. That’s a lot of treatment, which is a lot of expense, but they needed to have the failsafe and redundancy to get the state on board with the project. The pipe connecting the two plants was above ground and later repurposed for the city’s indirect potable reuse system, which is still in use today. In the end, they reclaimed nearly two billion gallons of wastewater as drinking water. And they did it with 100% compliance with the standards. But more importantly, they showed that it could be done, essentially unlocking a new branch on the skill tree of engineering that other cities can emulate and build on.

A version of this post originally appeared on Tedium, Ernie Smith’s newsletter, which hunts for the end of the long tail. For roughly three decades, the JPEG has been the World Wide Web’s primary image format. But it wasn’t the one the Web started with. In fact, the first mainstream graphical browser, NCSA Mosaic, didn’t initially support inline JPEG files—just inline GIFs, along with a couple of other formats forgotten to history. However, the JPEG had many advantages over the format it quickly usurped. aspect_ratio Despite not appearing together right away—it first appeared in Netscape in 1995, three years after the image standard was officially published—the JPEG and web browser fit together naturally. JPEG files degraded more gracefully than GIFs, retaining more of the picture’s initial form—and that allowed the format to scale to greater levels of success. While it wasn’t capable of animation, it progressively expanded from something a modem could pokily render to a format that was good enough for high-end professional photography. For the internet’s purposes, the degradation was the important part. But it wasn’t the only thing that made the JPEG immensely valuable to the digital world. An essential part was that it was a documented standard built by numerous stakeholders. The GIF was a de facto standard. The JPEG was an actual one How important is it that JPEG was a standard? Let me tell you a story. During a 2013 New York Times interview conducted just before he received an award honoring his creation, GIF creator Steve Wilhite stepped into a debate he unwittingly created. Simply put, nobody knew how to pronounce the acronym for the image format he had fostered, the Graphics Interchange Format. He used the moment to attempt to set the record straight—it was pronounced like the peanut butter brand: “It is a soft ‘G,’ pronounced ‘jif.’ End of story,” he said. I posted a quote from Wilhite on my popular Tumblr around that time, a period when the social media site was the center of the GIF universe. And soon afterward, my post got thousands of reblogs—nearly all of them disagreeing with Wilhite. Soon, Wilhite’s quote became a meme. The situation paints how Wilhite, who died in 2022, did not develop his format by committee. He could say it sounded like “JIF” because he built it himself. He was handed the project as a CompuServe employee in 1987; he produced the object, and that was that. The initial document describing how it works? Dead simple. 38 years later, we’re still using the GIF—but it never rose to the same prevalence of JPEG. The JPEG, which formally emerged about five years later, was very much not that situation. Far from it, in fact—it’s the difference between a de facto standard and an actual one. And that proved essential to its eventual ubiquity. We’re going to degrade the quality of this image throughout this article. At its full image size, it’s 13.7 megabytes.Irina Iriser How the JPEG format came to life Built with input from dozens of stakeholders, the Joint Photographic Experts Group ultimately aimed to create a format that fit everyone’s needs. (Reflecting its committee-led roots, there would be no confusion about the format’s name—an acronym of the organization that designed it.) And when the format was finally unleashed on the world, it was the subject of a more than 600-page book. JPEG: Still Image Data Compression Standard, written by IBM employees and JPEG organization stakeholders William B. Pennebaker and Joan L. Mitchell, describes a landscape of multimedia imagery, held back without a way to balance the need for photorealistic images and immediacy. Standardization, they believed, could fix this. “The problem was not so much the lack of algorithms for image compression (as there is a long history of technical work in this area),” the authors wrote, “but, rather, the lack of a standard algorithm—one which would allow an interchange of images between diverse applications.” And they were absolutely right. For more than 30 years, JPEG has made high-quality, high-resolution photography accessible in operating systems far and wide. Although we no longer need to compress JPEGs to within an inch of their life, having that capability helped enable the modern internet. As the book notes, Mitchell and Pennebaker were given IBM’s support to follow through this research and work with the JPEG committee, and that support led them to develop many of the JPEG format’s foundational patents. Described in patents filed by Mitchell and Pennebaker in 1988, IBM and other members of the JPEG standards committee, such as AT&T and Canon, were developing ways to use compression to make high-quality images easier to deliver in confined settings. Each member brought their own needs to the process. Canon, obviously, was more focused on printers and photography, while AT&T’s interests were tied to data transmission. Together, the companies left behind a standard that has stood the test of time. All this means, funnily enough, that the first place that a program capable of using JPEG compression appeared was not MacOS or Windows, but OS/2—a fascinating-but-failed graphical operating system created by Pennebaker and Mitchell’s employer, IBM. As early as 1990, OS/2 supported the format through the OS/2 Image Support application. At 50 percent of its initial quality, the image is down to about 2.6 MB. By dropping half of the image’s quality, we brought it down to one-fifth of the original file size. Original image: Irina Iriser What a JPEG does when you heavily compress it The thing that differentiates a JPEG file from a PNG or a GIF is how the data degrades as you compress it. The goal for a JPEG image is to still look like a photo when all is said and done, even if some compression is necessary to make it all work at a reasonable size. That way, you can display something that looks close to the original image in fewer bytes. Or, as Pennebaker and Mitchell put it, “the most effective compression is achieved by approximating the original image (rather than reproducing it exactly).” Central to this is a compression process called discrete cosine transform (DCT), a lossy form of compression encoding heavily used in all sorts of compressed formats, most notably in digital audio and signal processing. Essentially, it delivers a lower-quality product by removing details, while still keeping the heart of the original product through approximation. The stronger the cosine transformation, the more compressed the final result. The algorithm, developed by researchers in the 1970s, essentially takes a grid of data and treats it as if you’re controlling its frequency with a knob. The data rate is controlled like water from a faucet: The more data you want, the higher the setting. DCT allows a trickle of data to still come out in highly compressed situations, even if it means a slightly compromised result. In other words, you may not keep all the data when you compress it, but DCT allows you to keep the heart of it. (See this video for a more technical but still somewhat easy-to-follow description of DCT.) DCT is everywhere. If you have ever seen a streaming video or an online radio stream that degraded in quality because your bandwidth suddenly declined, you’ve witnessed DCT being utilized in real time. A JPEG file doesn’t have to leverage the DCT with just one method, as JPEG: Still Image Data Compression Standard explains: The JPEG standard describes a family of large image compression techniques, rather than a single compression technique. It provides a “tool kit” of compression techniques from which applications can select elements that satisfy their particular requirements. The toolkit has four modes: Sequential DCT, which displays the compressed image in order, like a window shade slowly being rolled down Progressive DCT, which displays the full image in the lowest-resolution format, then adds detail as more information rolls in Sequential lossless, which uses the window shade format but doesn’t compress the image Hierarchical mode, which combines the prior three modes—so maybe it starts with a progressive mode, then loads DCT compression slowly, but then reaches a lossless final result At the time the JPEG was being created, modems were extremely common. That meant images loaded slowly, making Progressive DCT the most fitting format for the early internet. Over time, the progressive DCT mode has become less common, as many computers can simply load the sequential DCT in one fell swoop. That same forest, saved at 5 percent quality. Down to about 419 kilobytes.Original image: Irina Iriser When an image is compressed with DCT, the change tends to be less noticeable in busier, more textured areas of the picture, like hair or foliage. Those areas are harder to compress, which means they keep their integrity longer. It tends to be more noticeable, however, with solid colors or in areas where the image sharply changes from one color to another—like text on a page. Ever screenshot a social media post, only for it to look noisy? Congratulations, you just made a JPEG file. Other formats, like PNG, do better with text, because their compression format is intended to be non-lossy. (Side note: PNG’s compression format, DEFLATE, was designed by Phil Katz, who also created the ZIP format. The PNG format uses it in part because it was a license-free compression format. So it turns out the brilliant coder with the sad life story improved the internet in multiple ways before his untimely passing.) In many ways, the JPEG is one tool in our image-making toolkit. Despite its age and maturity, it remains one of our best options for sharing photos on the internet. But it is not a tool for every setting—despite the fact that, like a wrench sometimes used as a hammer, we often leverage it that way. Forgent Networks claimed to own the JPEG’s defining algorithm The JPEG format gained popularity in the ’90s for reasons beyond the quality of the format. Patents also played a role: Starting in 1994, the tech company Unisys attempted to bill individual users who relied on GIF files, which used a patent the company owned. This made the free-to-use JPEG more popular. (This situation also led to the creation of the patent-free PNG format.) While the JPEG was standards-based, it could still have faced the same fate as the GIF, thanks to the quirks of the patent system. A few years before the file format came to life, a pair of Compression Labs employees filed a patent application that dealt with the compression of motion graphics. By the time anyone noticed its similarity to JPEG compression, the format was ubiquitous. Our forest, saved at 1 percent quality. This image is only about 239 KB in size, yet it’s still easily recognizable as the same photo. That’s the power of the JPEG.Original image: Irina Iriser Then in 1997, a company named Forgent Networks acquired Compression Labs. The company eventually spotted the patent and began filing lawsuits over it, a series of events it saw as a stroke of good luck. “The patent, in some respects, is a lottery ticket,” Forgent Chief Financial Officer Jay Peterson told CNET in 2005. “If you told me five years ago that ‘You have the patent for JPEG,’ I wouldn’t have believed it.” While Forgent’s claim of ownership of the JPEG compression algorithm was tenuous, it ultimately saw more success with its legal battles than Unisys did. The company earned more than $100 million from digital camera makers before the patent finally ran out of steam around 2007. The company also attempted to extract licensing fees from the PC industry. Eventually, Forgent agreed to a modest $8 million settlement. As the company took an increasingly aggressive approach to its acquired patent, it began to lose battles both in the court of public opinion and in actual courtrooms. Critics pounced on examples of prior art, while courts limited the patent’s use to motion-based uses like video. By 2007, Forgent’s compression patent expired—and its litigation-heavy approach to business went away. That year, the company became Asure Software, which now specializes in payroll and HR solutions. Talk about a reboot. Why the JPEG won’t die The JPEG file format has served us well. It’s been difficult to remove the format from its perch. The JPEG 2000 format, for example, was intended to supplant it by offering more lossless options and better performance. The format is widely used by the Library of Congress and specialized sites like the Internet Archive, however, it is less popular as an end-user format. See the forest JPEG degrade from its full resolution to 1 percent quality in this GIF. Original image: Irina Iriser Other image technologies have had somewhat more luck getting past the JPEG format. The Google-supported WebP is popular with website developers (and controversial with end users). Meanwhile, the formats AVIF and HEIC, each developed by standards bodies, have largely outpaced both JPEG and JPEG 2000. Still, the JPEG will be difficult to kill at this juncture. These days, the format is similar to MP3 or ZIP files—two legacy formats too popular and widely used to kill. Other formats that compress the files better and do the same things more efficiently are out there, but it’s difficult to topple a format with a 30-year head start. Shaking off the JPEG is easier said than done. I think most people will be fine to keep it around. Ernie Smith is the editor of Tedium, a long-running newsletter that hunts for the end of the long tail.

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