Son of George Arndt and Sophia Klemma of Germany. Husband of Maude E. Arndt.
He was manager of Western Supply Co.
Lived at 4327 Kossuth? in St. Louis City
Died of liver cancer
buried at Valhalla Cemetery
http://www.sos.mo.gov/images/archives/deathcerts/1927/1927_00033428.PDF

Name: Otto Arndt
Event Type: Census
Event Year: 1880
Event Place: Mascoutah, St. Clair, Illinois, United States
Gender: Male
Age: 4
Marital Status: Single
Race: White
Race (Original): W
Occupation: At Home
Relationship to Head of Household: Son
Relationship to Head of Household (Original): Son
Birth Year (Estimated): 1876
Birthplace: Illinois, United States
Father's Birthplace: Germany
Mother's Birthplace: Germany
Affiliate Name: The U.S. National Archives and Records Administration (NARA)
Affiliate Publication Number: T9
Affiliate Film Number: 0247
Household Role Gender Age Birthplace
George Arndt Self M 49 Germany
Sophia Arndt Wife F 42 Germany
Charles Arndt Son M 19 Illinois, United States
George Arndt Son M 17 Illinois, United States
Otto Arndt Son M 4 Illinois, United States

Name: Otto W Arndt
Event Type: Census
Event Year: 1900
Event Place: Precinct 11 St. Louis city Ward 13, St. Louis, Missouri, United States
Gender: Male
Age: 25
Marital Status: Single
Race: White
Race (Original): W
Relationship to Head of Household: Lodger
Relationship to Head of Household (Original): Lodger
Birth Date: Jul 1875
Birthplace: Illinois
Father's Birthplace: Germany
Mother's Birthplace: Germany
Household Role Gender Age Birthplace
Ulrich Singer Head M 49 Switzerland
Caroline Singer Wife F 44 Illinois
Bertha R Singer Daughter F 19 Missouri
Ulrich J Singer Son M 27 Missouri
W Julius Singer Son M 27 Missouri
Ella A E Singer Daughter F 11 Missouri
Rosa C Solim Niece F 26 Missouri
Caroline Scholt Mother-in-law F 82 France
William H Campbell Lodger M 62 Ohio
Otto W Arndt Lodger M 25 Illinois

Name: Otto W Arndt
Event Type: Census
Event Year: 1910
Event Place: St Louis Ward 15, St Louis (Independent City), Missouri, United States
Gender: Male
Age: 34
Marital Status: Single
Race: White
Race (Original): White
Relationship to Head of Household: Boarder
Relationship to Head of Household (Original): Boarder
Birth Year (Estimated): 1876
Birthplace: Illinois
Father's Birthplace: Germany
Mother's Birthplace: Germany
Household Role Gender Age Birthplace
Ulrich Singer Head M 59 Switzerland
Caroline M Singer Wife F 54 Illinois
Otto W Arndt Boarder M 34 Illinois

Could be them?
Name: Otto W Arndt
Event Type: Census
Event Year: 1920
Event Place: St Louis Ward 21, St Louis (Independent City), Missouri, United States
Gender: Male
Age: 55
Marital Status: Married
Race: White
Race (Original): White
Can Read: Yes
Can Write: Yes
Relationship to Head of Household: Head
Relationship to Head of Household (Original): Head
Own or Rent: Rent
Birth Year (Estimated): 1865
Birthplace: Illinois
Father's Birthplace: Germany
Mother's Birthplace: Germany
Household Role Gender Age Birthplace
Otto W Arndt Head M 55 Illinois
Mary E Arndt Wife F 39 Missouri