After a four month internship at the district capital, he was assigned to the Loto territory, which at the time was little known, had little infrastructure and few means of communication.

This was a difficult task with many problems in providing housing, food and medical care for the laborers, and constant coordination between the different services and groups involved.

He had to deal with disturbances in Matadi that year, including strikes, destruction of property and imprisonment of Europeans by the rebels.

[2] On 1 July 1953 Nauwelaert was made governor of Léopoldville Province, holding office until he retired from the colonial service on 28 February 1955.

[3] From 1955 to 1960 he remained in Léopoldville as general representative of the Congolese cotton company (Société cotonnière congolaise), of which he became administrator on 11 July 1960.