Plants for peat beds used for residential effluent dispersal

I am a Registered Onsite Wastewater Practicioner. I design and install septic systems in South Western British Columbia. One product that we are using quite often are constructed wetlands. We use small peat beds for residential effluent dispersal. Effluent is pretreated by an aerobic process before disposal. Do you have any recommendations as to types of vegetation our clients should plant in these peat beds. One concern we have is roots of certain plants causing havoc with buried components. Any comments or advice would be appreciated

Thanks,

Pacific Onsite Solutions
North Vancouver B.C.
604-998-3390
www.pacificonsite.com