The Reds centre-back has put up the money to help kick-start the company called KloAgger, which literally translates as Agger toilet.
Daniel's younger brother Marco Agger will run the firm alongside friend Rune Rasmussen in his native Denmark.
Rasmussen has declared that Agger decided to invest in the Danish economy to help create jobs in his homeland.
He told reporters: "Daniel could have chosen to keep his money abroad, where taxes are lower, but he has opted to invest in Denmark to create jobs.
"Some four million krone, £450,000, have been invested. I hope this sewer company will become one of the largest in the industry."
Agger has also hit the headlines this week after refusing a payment owed to him by Danish club Bronby, who are struggling financially.