Pig Shit and City effluent (Score 1)

There are currently issues with too much pig shit. Create 100 9 mile x 15 miles algae ponds and use all the excess pig shit. Also effluent from large cities could be added also. this could be done in California, Nevada, Utah and Arizona Deserts. It might change the climate a little bit by adding extra h2O to the air, hydrating that dry environment but it would be worth it.
What the heck make it 200 ponds and just the Airline Industry.
Or how about the Sahara Desert and maybe turn the Sahara partially back into usable land mass by doing something similar there?