Accomodation options :

Adagio Acces Brussels Delta (at a few bus stops from the ULB, but it’s not a touristic zone)
Situated in front of the CHIREC, 207 bd du Triomphe
1160    Bruxelles
02/ 854 15 10
Book your stay on adagio-city.com | Adagio
There are three of them in Brussels. The closest one to the ULB is Adagio Delta.
 
Ibis Châtelain (accessible by tramway)
191 chaussée de Vleurgat - 1050 Bruxelles
02/850 93 30
ibis Brussels Centre Châtelain: Convenient and Trendy Hotel - ALL (accor.com)
L'hôtel Aqua a 97 chambres et l'hôtel Argus a 43 chambres. (20 minutes away from the ULB - Porte de Namur - Toison d’Or).
 
Hôtel Argus
Rue Capitaine Crespel 6, 1050 Ixelles
02/514 07 70
info@argus-hotel.be
Argus Hotel Brussels - Guest Reservations

L’hôtel Aqua
43, rue de Stassart
1050 Bruxelles
02/213 01 01
https://www.aqua-hotel-brussels.com/fr/accueil

All these rooms can be rented as singles.
At the Aqua there is a large majority of twin rooms (two single beds in each room) and 8 double rooms (one double bed). At the Argus there is a mixture of single, twin and double rooms (one double bed).
 
Thon Hotel Bristol Stephanie
91 avenue Louise
1050    Bruxelles
Thon Hotel Bristol Stephanie | Thon Hotels

Warwick Barsey hotels 4*
381-383, avenue Louise
1050 Bruxelles
Warwick Brussels | 4 Star Hotel near Brussels Grand Place (warwickhotels.com)

Ibis Styles Brussels Louise
Avenue Louise 212
1050 BRUSSELS Belgique
Téléphone+32 2 644 29 29
Email de contactH8915@accor.com
ibis Styles Hotel Brussels Louise - Guest Reservations

Other possibilities

The following hotels are located near the Grand Place, in the centre of Brussels

Hotel Agora Bruxelles Grand Place
3 rue des Eperonniers
1000    Bruxelles
02/502 36 41
Hôtel Agora Bruxelles Grand Place - L'hôtel vert. (hotelagora.be)

Hotel Ibis Brussels off Grand-Place
100, Marché aux herbes
1000    Bruxelles
02/500 86 86
H1046@accor.com
ibis Brussels off Grand Place : hôtel central - ALL (accor.com)

Novotel Brussels
120, Marché aux herbes
1000    Bruxelles
02 620 04 29
H1030@accor.com
Novotel Brussels Off Grand Place: hotel in centre - ALL (accor.com)

Les Bed and Breakfast :

Bed&Brussels

Ixelles :

Airbnb possibilities

Appart -hôtels
https://www.citadines.com/en/belgium/brussels/citadines-toison-dor-brussels.html

https://www.b-aparthotels.com/fr/

http://www.axlflathotel.be/

http://www.budgetplaces.com/fr/bruxelles/liste-de-bed_and_breakfast-pas-chers/

Youth Hostels :

(LAJ)