Changes

|style="text-align:left;"|'''Pros'''

|style="text-align:left;"|'''Pros'''

*Well established technology

*Well established technology

*May be natural looking, although often rectilinear in plan

*May be natural looking

*Need little to no gradient

*Need little to no gradient

*Provides buffer to discharge

*Provides buffer to discharge

|style="text-align:left;"|'''Pros'''

|style="text-align:left;"|'''Pros'''

*High levels of treatment possible

*High levels of treatment possible

*May be run without power if significant gradient is available

*May be run without power if significant gradient is avaialble

*Can be attractively designed to generate interest in the technology, may be any shape.  

*Can be attractively designed to generate interest in the technology.  

*Maintenance is technically simple. Sludge easily removed

*Maintenance is technically simple

*Biologically complex and robust

*Biologically complex and robust

*Failure tends to be gradual

*Failure tends to be gradual