Knowledge about various tests that are used to find the different components like ammonia, nitrate, nitrite, phenol etc present in waste water can be discussed in this discussion window. This would be of great help for me and for others as well.
Chhavi , most of your parameters can be measured by normal spectrophotometeric method. In particular Potassium by flame photometer/ AAS/ ICP-MS. As Bayan very rightly mentioned, consult APHA , is a good option