High Altitude Wastewater Treatment

Hi Everyone;

I have a rather unique problem and am trying to identify the best WWTP solution for high altitude projects to try and prevent environmental pollution in the Himalayas. The requirements are:

1. To be installed at elevations greater than 3000m.

2. Must be able to function in low oxygen environments.

3. Must be compact due to difficulty of getting equipment to site.

4.Loads per site will range from 1 - 100 KLD

If anybody out there has any experience with such WWTP please tell me what you propose. They are currently using soak pits with the runoff flowing downslope.