Dealing with waste water

Question

I am trying to deal with waste water;

If process one generates 1 kg of water untreated

Process two generates 1.5 kg of water untreated

process three generates 2 kg of water untreated

I then create process four =overall water to be treated= 4.5 kg of water to be treated

Process five i use an openlca process called waste water treatment at waste water treatment plant..

However the outputs of process five have only -1 kg of  waste water treated

Do i need to multiply all the inputs and outputs on process five by 4.5 kg (from process four) to ensure this process is aligned with my project?

Thank you

Answer 1

the 

openlca process called waste water treatment at waste water treatment plant

is probably from ecoinvent? You only need to connect your processes with the ecoinvent background process, openLCA will scale the factors correctly, but in this case (waste and waste water treatments in ecoinvent) you should model with "double negative" (set your 4.5 kg also negative, just as the ecoinvent flow is negative) to avoid violiation of mass conservation principle.