You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Bill_%26_Melinda_Gates_Foundation

Context:
Since the launch of the "Reinvent the Toilet Challenge", more than a dozen research teams, mainly at universities in the U.S., Europe, India, China and South Africa, have received grants to develop innovative on-site and off-site waste treatment solutions for the urban poor. The grants were in the order of 400,000 USD for their first phase, followed by typically 1-3 million USD for their second phase; many of them investigated resource recovery or processing technologies for excreta or fecal sludge.

Question:
What did many investigate 

many of them investigated resource recovery or processing technologies for excreta or fecal sludge.