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Q&A with John Pujol: Tackling Arsenic-Tainted Water

John Pujol and his team at SimpleWater, a Berkeley-based engineering firm, have developed a new way to put contaminated wells back into service by making friends with the age-old process of rusting metal. It could be cheaper and easier for many communities dealing with arsenic problems.

Written by Matt Weiser Published on Read time Approx. 4 minutes

The way some people look at it, California has plenty of water to survive its periodic droughts. The problem is much of that water isn’t drinkable, and can’t be made drinkable, because it is too contaminated.

This is how John Pujol sees the situation. As CEO of SimpleWater, he has helped develop a new method to remove arsenic from groundwater. Arsenic is a naturally occurring element, but beyond a certain concentration it can cause a variety of health problems, including cancer, and can even be fatal when it arises in excessive quantities. More than 2,200 California drinking water sources are tainted by arsenic, and 600 of these exceed the state’s regulatory standard for arsenic contamination.

Rigid federal water quality standards exist to protect the public from arsenic in drinking water. But those standards often require communities to spend millions of dollars seeking a new water supply or paying for expensive filtration systems that often don’t work well or cost too much for small water systems to afford.

Pujol and his colleagues believe they have a much simpler solution using an age-old natural principle: rust. Their system, called ArsenicVolt, uses the erosive process of rusting metal to capture and extract arsenic from water. It was developed at Lawrence Berkeley Laboratory by two of Pujol’s partners. SimpleWater holds a license to market the technology.

The goal is an easier and cheaper system to help small communities revive productive wells tainted by arsenic. Water Deeply recently interviewed Pujol in Albuquerque, N.M., where his company was selected to compete for $50,000 in startup funds at a Village Capital venture funding event.

Water Deeply: How serious is the arsenic problem?

John Pujol: An estimated 4 million Americans are drinking water with arsenic in it. This creates a 1-in-300 chance of developing cancer. There’s a lot of places in California where they cannot access their water in a drought because of a very small arsenic problem. It’s not like there’s no water in California. It’s just that it’s dirty.

Water Deeply: What’s the typical solution?

Pujol: You either have to drill new wells – and that’s a gamble – or you treat the water you’ve got, and that can get very expensive. Many treatment systems rely on filters or chemicals. These also require a staff to maintain and monitor.

Water Deeply: How does your water treatment system work?

Pujol: It’s a process called electrochemical arsenic remediation, or ECAR. We immerse an iron plate in the water flow. Then when we electrify the iron plate with a particular current, it coaxes iron particles off the plate. These bind with the arsenic in the water and settle out, leaving the water clean.

It’s really painfully easy. This is an opportunity to change the way we treat water – switch it away from complexity. But scientifically, it’s unknown exactly what the mechanism is. Chances are, iron is a very good coagulant, so it’s good at removing any charged particles (like arsenic).

Water Deeply: Is your system in use anywhere currently?

Pujol: We’ve done a number of test projects. And later this year we’ll launch our first significant pilot project in the town of Grimes, in Colusa County, California, which has about 500 water connections. It’s a very low-income area, and they’ve already tried three other solutions, all of which were either ineffective or too expensive.

Water Deeply: How much will this cost, and who’s paying for it?

Pujol: It will cost between $300,000 and $400,000, which is more than it would cost in normal operating conditions because that includes extensive documentation and data analysis. Even so, we estimate it will be 60 percent cheaper than what they’ve tried before, mostly from operational savings. They won’t need to hire engineers or buy any chemicals.

Every small water system has been burned at least once after paying for a full pilot project and then finding out afterward that it’s too expensive. There’s a Red Sea of failed arsenic technologies. So when we show up, we have to be careful. That’s why we’re paying for the pilot in Grimes with help from a $100,000 grant from the EPA (U.S. Environmental Protection Agency).

Water Deeply: Doesn’t the iron plate eventually erode away completely in your process?

Pujol: Yes, it nearly corrodes the iron plate to extinction. And it creates a nontoxic, arsenic-laden solid waste from the eroded iron particles, which are gathered in a collection tank. But then our trucks will come pick up the old iron plate, replace it with a new one, and we’ll haul away the waste material. The water agency doesn’t have to manage this.

Water Deeply: What other projects are you working on?

Pujol: We’re working on a subscription-based water filtration solution for homeowners that we call DropDrop. It’s a small filter that screws onto your kitchen faucet. It’s a coconut-fiber cartridge that filters out lead, chlorine, arsenic and pharmaceuticals.

Our goal, ultimately, is to shift water treatment away from the current model of a centralized water treatment facility. This is proving inadequate to treat the water problems we have in America today. No longer will municipalities have to solve water-quality problems on a regional basis. They can solve it at the tap.

Water Deeply: How much will this cost?

Pujol: We’re estimating it will cost the homeowner $7 per month. The problem with current faucet filters is that the replacement filters have to be purchased at a store, and you have to find a store that sells the right one. Also, many of these are clunky objects that get in the way of washing dishes, or they’re installed under the sink where they are easily neglected. Often, the homeowner forgets to change the filter for months and months, which renders the filter useless. Or they can’t find a replacement.

With our solution, for a subscription fee of just $7 per month, the homeowner gets a new filter in their mailbox every month, which serves as a reminder and an incentive to change out the old one. And it’s easy: You just unscrew the end of your faucet just like you’re installing a faucet aerator. Then you pop out the old filter, drop in the new one, and screw it back together. No tools required.

Top image: John Pujol, CEO of SimpleWater, shown at a Village Capital venture funding competition in Albuquerque in November 2015. (

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