>>> THE METROPOLITAN WATER RECLAMATION DISTRICT HAS BEEN CALLED THE MOST IMPORTANT GOVERNMENT AGENCY THAT NOBODY KNOWS ABOUT.

YOU KNOW ABOUT IT?

IT'S THE AGENCY THAT TREATS STORM WATER AND WASTEWATER FOR MORE THAN 5 MILLION PEOPLE IN COOK COUNTY.

ONE OF THE METHODS TO TREAT THAT WATER IS A SURPRISING WAY TO REUSE A BYPRODUCT.

THE CREATION OF A VERY POPULAR BEVERAGE.

CHICAGO TONIGHT NICK BLUMBERG HAS THAT STORY.

>> WITHOUT CLEAN WATER, YOUR FAVORITE LOCAL BEER WOULDN'T EXIST.

>> WATER IS THE NUMBER ONE INGREDIENT IN OUR BEER.

WE USE LAKE MICHIGAN WATER.

>> THAT'S WHY WHEN THE METROPOLITAN WATER RECLAMATION DISTRICT APPROACH RESOLUTION BREWING ABOUT TAKING SOME OF THE BYPRODUCT FROM ITS BREWERY OFF THEIR HANDS, JOSH DETH AND HIS COLLEAGUES WERE ALL EARS.

BYPRODUCT IS SPENT YEAST.

>> THIS HOLDS A WEEK WORTH OF WASTE, WHICH IS A PRETTY BIG TANK .

THESE ARE 24 FOOT CEILINGS HERE.

THE HOPS AND THE YEAST FALL TO THE BOTTOM OF THE TANK.

THEY GATHER IN THE CONE.

>> Reporter: ONCE THAT YEAST HAS PLAYED ITS PART FERMENTING THE BEER, REVOLUTION DOESN'T HAVE A USE FOR IT.

>> PREVIOUSLY, WE WOULD'VE JUST PUT IT DOWN THE DRAIN AND FLUSHED IT DOWN WITH SOME EXTRA WATER, SEND IT OUT TO THE CITY SEWER SYSTEM.

THIS PROGRAM THAT WE'RE FOCUSING ON TODAY IS A WAY TO REPURPOSE THAT INGREDIENT, GIVEN A HIGHER PURPOSE.

AND THAT PURPOSE?

USING THE CARBON RICH SPENT YEAST TO REDUCE THE AMOUNT OF PHOSPHORUS IN THE WATER MWRD TREATS.

IF THERE'S TOO MUCH PHOSPHORUS IN THE WATER, THAT CAN FEED MICROORGANISMS THAT CAN HARM WATER.

>> THEY WANT TO EAT, AND THEY WANT TO REPRODUCE.

AND WHEN THEY REPRODUCE, YOU END UP WITH THAT LOOK LIKE ALGAL BLOOMS THAT CAN THEN LEAD TO FISH CAMPS, AND THEN IT CAN LEAD TO DEAD ZONES.

>> Reporter: ON A RECENT THURSDAY, A TRUCK FULL OF SPENT YEAST ARRIVES AT THE MWRD 400+ ACRE STICKNEY FACILITY IN CICERO.

A HOSE CONNECTS THE TANKER TO AN UNDERGROUND RECEPTACLE FOR THE SPENT YEAST, AND A STAFFER TEST THAT THE MATERIAL FROM THE BREWERY IS SAFE.

>> I REMEMBER WHEN THE FIRST TRUCKS CAME IN, WE KIND OF JOKED, SHOULD WE BOTTLE THAT, BECAUSE IT SMELLS REALLY GOOD.

>> I CAN CONFIRM THAT IT DOES SMELL LIKE BEER.

>> Reporter: USING THE FRAGRANT BYPRODUCT IS ONE WAY THE MWRD SAYS IT WANTS TO MOVE AWAY FROM A MIND-SET OF WATER TREATMENT TO RESOURCE RECOVERY.

EVEN THE PHOSPHORUS AT THE MWRD, IT'S REUSING THAT TO MAKE FERTILIZER.

>> RECYCLING MATERIALS.

WE'RE COVERING THINGS LET YOU WOULD HAVE THROWN IN THE GARBAGE , AND NOW ARE JUST BASICALLY SAYING, LIKE, WAIT, I CAN REUSE THAT FOR SOMETHING ELSE.

>> JOSH DETH HAS HELPED ENCOURAGE OTHER LOCAL BREWERIES TO GET INVOLVED IN THE RESOURCE RECOVERY PROGRAM TOO.

>> WE ACTUALLY SAVE MONEY BY NOT HAVING TO PAY MONEY TO THE MWRD , IN ADDITION TO MAKING GOOD ENVIRONMENTAL.

>> ON CITIES LIKE JACKSON MISSISSIPPI , WATER.

WE'RE LUCKY TO LIVE SO CLOSE TO ONE OF THE WORLD'S LARGEST WATER RESOURCES IN THE GREAT LAKES.

WE SHOULD MAKE SURE THAT WE DON'T TAKE IT FOR GRANTED.

>> Reporter: THE PROGRAMS INNOVATIVE, AND MWRD LEADERS WANT TO KEEP THE MOMENTUM GOING.

>> WE'RE LOOKING AT OTHER WAYS.

TO USE THIS RESOURCE, SO WE CAN ALL HAVE A WIN-WIN SITUATION.

>> THE ADDRESS REMEMBER, NEXT TIME YOU LIFT A GLASS OF LOCALLY BREWED HERE, IT JUST MIGHT BE DOING YOUR PART TO HELP THE ENVIRONMENT.

FOR CHICAGO TONIGHT, I'M NICK BLUMBERG.