COMPLIANCE INFO_1992-2001 - Laserfiche WebLink

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t pend on the crop, the number of plots in the Loading rates for Other rotation cycle, and other management condi- tions. constituents Suspended solids and dissolved solids (TDS) Infiltration/percolation method. With this must also be considered in determining load- system,the organic loading rate is very impor- ing rates for land application systems. tant because it is related to the development of anaerobic conditions,which are particularly a Suspended solids. Too high a concentration problem where large amounts of water pass of suspended solids can clog application through the soil. To meet the oxygen demand equipment and reduce infiltration into the created by decomposing organic and nit- soil.As a result, it may be necessary to reduce rogenous material, an intermittent loading suspended solids (for example, in a settling schedule is required for these systems. One pond) before application. study reports a BOD loading of 45 pounds(20 kilograms) per acre per day and a liquid load- Dissolved solids. Dissolved solids in waste Ing rate of 300 acre-feet per acre per year. The water may be classed by the extent of their application cycle consisted of 14 days of load- movement with percolating water through the Ing followed by 10 days of resting in the sum- soil. Chloride, nitrate, sufate, and bicarbo- mer and 20 days of resting in the winter. nates move relatively easily through most soils.These elements can therefore be leached with additional applications of waste water or Overland flow method. With this system, by rainfall. Other dissolved solids such as the limits of organic loading are at present sodium,potassium,calcium,and magnesium undefined.High strength organic wastes have are exchangeable and react with the soil so been applied at BOD loadings of 40 to 100 that their concentrations in the percolating pounds(18 to 45 kilograms)per acre per day. water may change with depth. Constituents A grass infiltration system has been loaded such as boron, fluoride, and other trace ele- �' with 68 pounds (31 kilograms) of BOD per ments may or may not be removed from the 1 acre per day with a 96 percent removal effi- soil matrix depending upon such factors as ciency.Another study reports 92 to 95 percent clay content, soil acidity, and soil chemical removal of BOD at loadings of 14 to 18 pounds balance. (6.4 _to 8.2 kilograms) per acre per day. Be- cause the organic matter is filtered out by Constituents with potentially limiting loading grass, litter, and top soil, and is also reduced rates should be identified and their maximum by biological oxidation,the organic content of loading rate calculated.The resulting land re- the soils is not substantially affected. quirement should be compared with those for liquids and organic matter with the most lim- A resting period is also important with over- sting constituent determining the minimum land flow systems. The length of the resting treatment area. However, the actual total period varies depending on climatic condi- acreage required for the system will be some- tions, harvest requirements, and insect con- what larger than this minimum,as discussed trol considerations. in the next section. Land Requirement The total land area required for a waste water disposal system includes treatment areas, buffer zones,storage(if necessary),sites for buildings,roads and ditches,and land for emergencies or future expansion. If any on-site preapplication treatments such as screening, sedimentation, biological or chemical treatment, or disinfection are re- quired, an allowance must be made for the land needed. As stated above, the land requirement for the actual treatment areas is the largest area of need based on the acceptable loading rates for liquids, organic matter, or other constituents. 14