A method for solidifying cementitious wastewater by combining the wastewater with a super absorbent polymer composition that includes a UV-stabilizer to form a mixture and disposing of the mixture as solid construction waste. The UV-stabilizer may be a stabilizing additive in the super absorbent polymer composition that inhibits the reversion from a solid or semi-solid mixture back to a liquid. In some embodiments, the method includes placing the mixture in UV-light non-transmissive packaging. After placing the mixture in the UV-light non-transmissive packaging, the package is closed and can be permanently sealed. The sealed package with solidified material therein can then be disposed as solid construction waste. The super absorbent polymer composition can include zeolite or other molecular sieves.