Waste water flow varies widely in how much waste is mixed in with the water.  A traditional septic tank removes a portion of waste from the water before passing effluent to a dispersal area.  When dispersing effluent becomes more challenging due usually to limited space and/or challenging soil, it may be necessary to cut down the size of the dispersal area.  Pre-treatment of effluent before release to dispersal routinely decreases the size of an effluent dispersal area by a factor of 2.  The pretreatment system usually is required to drop the BOD (biological oxygen demand) and the TSS (total suspended solids) to a maximum of 30 mg/liter.  This is much cleaner than effluent usually leaving a septic tank.  Pretreatment systems used for decreasing dispersal area size usually do not remove all the pathogenic organisms or nitrogen from effluent.  Therefore, proper disposal in a soil based bed is still necessary to complete the treatment process, after pretreatment.  There are 15 manufacturers of pretreatment systems and alternative dispersal equipment that are currently certified by the State of VT to install equipment here.  Pricing and maintenance vary from one system to another, all require more maintenance, many require electricity, to operate.  Hogg Hill Design works closely with property owners and equipment suppliers to make sure the end result is well understood before the design is completed and permit issued by the State.  

 Orenco AX20RTB - pre-treatment unit  - up to 4 bedrooms