In the drawing a wastewater treatment plant is shown within an urban area, and a rural agricultural area is also shown adjacent to the urban area. A river flows between these two areas. The surface water outlet from the wastewater treatment plant, where clean treated effluent water is discharged to the river, is shown beside the river and near the treatment plant.
Two forms of truck transport of the sewage biosolids from the treatment plant to the land application sites are shown in the drawing. An open box transport truck is shown hauling dewatered (semi-solid) sewage biosolids to one of the sites. And a closed tank truck is shown leaving the other land application site after having just delivered its load of liquid sewage biosolids.
There is a rural residence adjacent to both of the land application sites. One site is beside the residence on the same side of the road, and the other site is directly across the road from the residence. At the site across the road a tractor and injection unit is shown injecting liquid sewage biosolids into the soil of a farm field. Also shown are two dotted lines overlaid on to this part of the drawing. One depicts the required minimum 15 m horizontal separation distance from the well of the residence, and is drawn as a 15 m radius around the well. The other depicts the required minimum 25 m horizontal separation distance from the residence itself and is drawn as 25 m radius around the residence. Liquid sewage biosolids may not be applied to areas of the field that are located between the dotted line and the well, or the dotted line and the residence.
At the land application site beside the residence a front-end loader is shown loading dewatered (semi-solid) sewage biosolids into a surface spreader (e.g. manure spreader). A tractor pulling a surface spreader and applying the dewatered biosolids to the surface of the field is also shown. Two dotted lines are also shown overlaid on this part of the drawing. One depicts the required minimum 90 m horizontal separation distance from the residence if the sewage biosolids are not incorporated into the soil after application. This dotted line is drawn as a 90 m radius around the house. Dewatered sewage biosolids may not be applied to areas of the field that are located between the dotted line and the residence. The other dotted line depicts the minimum 20 m horizontal separation distance from the upper bank of a surface watercourse that is adjacent to the site. A minimum 20 m horizontal separation distance from the upper bank of a surface watercourse is a regulatory requirement when applying all forms of sewage biosolids, not just dewatered sewage biosolids.
And finally, the lower portion of the drawing depicts a vertical cross-section
of the soil where liquid sewage biosolids are being injected into the soil.
At one point along this cross-section a dotted line is shown 0.3 m below the
surface of the soil. This is the minimum depth of unsaturated soil that must
be present at the time of application of the sewage biosolids. At another point
along the vertical cross-section consolidated bedrock is shown at a depth of
1.5 m below the surface of the soil. This is the minimum depth of soil material
that must be present over bedrock in order to apply sewage biosolids to an agricultural
site. Both of these last two standards apply to the land application of all
types of sewage biosolids, not just liquid sewage biosolids.