Consider the following statements regarding activated sludge process:
1. Industries prefer activated sludge process as it requires less space, does not produce obnoxious odours and requires less time for waste water treatment compared to trickling filter.
2. It requires skilled supervision
3. Biological treatment is enhanced because shock loadings are eliminated.
Which of the above statements are correct?
1. 1 and 2 only
2. 1 and 3 only
3. 2 and 3 only
4. 1, 2 and 3