Wastewater Exam 3

What general relationship does soil texture have with soil porosity and how does this relationship influence wastewater movement?

Soil texture is used to infer porosity and predict wastewater transmission through soil. Sandy soils typically have fewer but larger pores than clay soils. Wastewater moves quicker through sands than clays.

Sand ranges in diameter from

2 to 0.05mm

Silt ranges in diameter from

0.05 to 0.002mm

Clay ranges in diameter from

less than 0.002 mm

Which soil particle has the largest surface area per given weight?

Clay

List 3 examples of soil structure that are unsuitable for onsite wastewater systems

Prismatic, Columnar, and Angular blocky, Massive, Platy

List 2 lab methods and 1 field method to determine soil structure

1 field: Texture by feel

2 Lab: Pipette, Hydrometer

What are redox reactions?

Reduction and oxidation couplings. Organic matter serves as an electron donor and O2, NO, Fe serves as the electron acceptor. Electron transfer for energy gain

LEO says GER

Loss of Electrons is Oxidation, Gain of Electrons is Reduction

For redox features to occur in soil, what 4 conditions/things must be present

Anaerobic conditions, Fe or Mn in soil, microbes, and carbon source (pH, temperature)

What do gray soil colors indicate

Periods of anaerobic, saturated conditions where iron has leached from soil

What are relict features? Provide example

Occur when soil colors are not in equilibrium with the current conditions

Example: drainage, addition of fill

What are lithochromic features. Provide examples

Colors inherited from the rock (parent material)

Example: Dune sands with low iron content

Most soils have between__ and __% porosity

35% and 50%

How does soil compaction influence bulk density of soil

Compaction increases bulk density

If low chroma colors are not accurate predictors of the seasonal high water table, then what may the implications with regards permitting onsite systems and the performance of an onsite system

May deny permits for a site that has sufficient depth of aerated soil or potentially permit a site that doesn’t have sufficient depth of aerated soil. If there isn’t enough aerated soil beneath the systems then wastewater contaminants may not be sufficiently treated before reaching groundwater.

If a landowner disagrees with the determination that their property doesn’t have sufficient depth of soil for an onsite system because of soil colors, what option does the owner have to appeal the decision?

The owner can hire a consultant to monitor groundwater levels in the proposed drainfield area during the wet season to measure the actual depth to groundwater

Soil layers are also called

Horizons

List the 5 soil forming factors

Parent material, climate, organisms, time, relief

__law states that larger soil particles settle faster than smaller soil particles

Stokes

A soil that ribbons over 2 inches and has a smooth feel is a

Silty clay

A soil that ribbons 1 ½ inches and has a gritty feel is a

Sandy clay loam