Virginia Law

APPENDIX H.

Land Disposal Criteria

The following sections are reproduced from the Commonwealth of Virginia Sewerage Regulations, State Department of Health and State Water Control Board February 1977.

25.07 Sludge and Solids Disposal

25.07.01 General

A plan shall be provided for the disposal of sludge and solids from each treatment facility as part of the final engineering documents (cf. Section 2.04.02). Before sludge is disposed of by land application, its short term and long term chemical effects on the land and groundwater must be evaluated. The evaluation program should consider the existing industrial waste surveys and general characteristics of the land to be used as well as other appropriate information. Adequate provisions for residue disposal, air pollution control, soil contamination prevention and groundwater/surface water contamination prevention shall be provided. Sludge shall not be applied to root crops or crops intended for human consumption in the raw form. Disposal of sludge shall be in such a manner as not to cause health hazards, destroy vegetation, create odor and/or vector problems, render the soil unsuitable for future land use or create other nuisances. Land areas proposed for sludge disposal should be remote from inhabited dwellings, water supplies and shellfish areas. Disposal of sludge to open dumps is prohibited. Designs incorporating the use of sludge as a soil conditioner should be forwarded to the Department of Agriculture and Commerce by the Department for appropriate review and comment.

25.07.02 Land Acquisition or Control

When land application constitutes a primary means of sludge disposal for a facility and the facility does not possess sufficient alternate disposal means, the continued availability of the land shall be protected. Such land shall also be protected from improper concurrent uses during utilization periods. The means of such protection for land availability and from improper concurrent uses shall be determined by the Department, the Board and the owner at the preliminary engineering conference.

25.07.03 Sludge Stabilization and Pathogen Reduction Prior to Land Application

Sludge shall be subjected to a treatment process which will stabilize many of the organic materials present in raw sludge. Anaerobic digestion, composing, aerobic digestion, heat treatment, processes or chemical treatment processes such as high lime or chlorine dosages are considered to produce stabilized sludges. For some projects, it may be necessary to achieve additional pathogen reduction beyond that attained by stabilization.

25.07.04 Sludge Composition and Soil Evaluation

The following parameters for sludge and soil composition may be employed to determine the sludge classification and suitability of soils for sludge application. Determination of specific parameters to be run shall be made at the preliminary engineering conference and the results of the analyses shall be included as a portion of the sludge disposal plan required in accordance with Section 25.07.01.

Appendix J contains forms which are recommended for use by the owner of the treatment facility in providing the results of background sludge and soil analyses. A one-quart soil sample shall be taken from the top four inches of soil and retained indefinitely.

After the sludge disposal plans required in accordance with Section 25.07.01 is approved by the Department and the Board, the Department and the Board waive the requirement for the sludge composition analyses and soil evaluation at any new application site for which either of the two following criteria apply:

a. the sludge is applied as a single application not to be repeated for at least five years.

b. the sludge application area is no larger than 10 acres.

This waiver in no way limits the powers of the Board and the Department in the control of any sludge application practice, regardless of frequency of application or size of the application area, for which groundwater contamination, surface runoff, soil toxicity, health hazards or nuisance conditions are considered to be a problem or a potential problem. Additionally, all other requirements contained in Section 25.07 including protection from improper concurrent uses, stabilization, sludge classification, application and disposal methods, soils, application rates, runoff control, sludge transport, etc. shall apply to all sludge application sites, regardless of size. As a further condition of this waiver provisions, the plant owner shall provide advance notification for concurrence to the appropriate Regional Offices of the Department and the Board of any new site(s) for which sludge application is intended. The notification for concurrence may be made by phone call to be confirmed in writing or by letter mailed in time to ensure receipt by the Department and Board prior to utilization of the new site(s). As a minimum, the notification for concurrence shall provide the location and size of the area, owner's name, proposed application rate, percentage of solids and any special or unusual conditions which may exist.

25.07.05 Sludge classification

Prior to land application, sludge shall be evaluated in accordance with Section 25.07.03 and 25.07.04. The sludge shall be classified by its characteristics. For new projects, sludge characteristics may be approximated by data obtained from like treatment facilities receiving flow from similar waste contributors. Pilot studies for sludge characteristics may be required when deemed appropriate by the Department and the Board.

a. Class A-Class A sludge shall be suitable for land application at the approved site in accordance with the approved application conditions indefinitely under proper management. Sludge which is classified as Class A shall be stabilized and shall not contain heavy metals or other undesirable components in quantities that (1) may be harmful to the production of crops, trees or other vegetation; (2) may result in crops or vegetation containing components which may be harmful to the health of animals or humans when consumed; (3) may render the soil unsuitable for future land use and (4) degrade existing groundwater quality. Appendix K presents standards for Class A sludge based on maximum allowable levels of certain heavy metals.

b. Class B-Class B sludge is sludge which is raw, partially stabilized, chemically or bacteriologically contaminated or contains undesirable components which makes it unfit for land application. This shall include unstabilized pumpage from septic tanks. Disposal of Class B sludge may be implemented by (1) conveyance to sewage treatment plant having approved sludge handling facilities, provided that detrimental effects to the plant shall not occur; (2) stabilization of sludge such that it shall meet the requirements of Section 25.07.05a, above; and (3) other methods which will be evaluated on a case by case basis. Raw or partially stabilized sludge shall be mixed with solid waste for disposal in solid waste landfills.

25.07.06 Application and Disposal Methods

Spray application of Class A sludge to the land is acceptable when no transport of aerosols beyond the boundaries of the application area is predicted.

a. Liquid Sludge

Liquid sludge shall generally have a solids content of less than 12 percent. Liquid Class A sludges shall be applied to land by plowing, discing, or direct injection so that the sludges are immediately covered or by spraying or spreading on pasture that has been clipped short, permanent crop land or land that is producing trees or nursery stock. Only application sites especially selected for sludge application and approved by the Department and the Board may be used. Liquid sludges shall not be mixed with solid wastes for disposal in solid waste landfills.

b. Final Dewatered Sludge

Final dewatered sludge is sludge that is dewatered for the purpose of ultimate disposal and is defined as having a solids content usually ranging between 12 percent and 30 percent. Dewatered sludges including those dewatered through the use of centrifuges, vacuum filters and filter presses may be disposed with solid wastes if the ratio of sludge is high enough so as to prevent problems with compaction and extruding of sludges to the surface of the ground. These dewatered sludges may also be disposed in separate trenches at approved solid waste landfill sites or other approved sites. Dewatered Class A sludges may also be applied to the land by plowing or discing into the soil immediately after application or by spraying or spreading on pasture that has been clipped short, permanent crop land or land that is producing trees or nursery stock. Only application sites especially selected for sludge application and approved by the Department and the Board may be used.

c. Dried Sludge

Dried sludge is sludge that has a solids content greater than 30 percent. Dried Class A sludges from treatment processes may be disposed in solid waste landfills or atop the landfills to promote growth of vegetation, landfills selected for sludge disposal or plowing or discing into the ground or by spraying or spreading on pasture that has been clipped short, permanent crop land or land that is producing trees or nursery stock. Only application sites especially selected from sludge application and approved by the Department and the Board may be used.

d. Other Solids

Grit, rages and other debris or screenings from sewage treatment plants shall be stored in covered containers. These solids are classified as Class B, and subsequent disposal shall be by burial at solid waste landfill sites or other sites approved by the Department and the Board.

25.07.07 Soil

Soils shall be well drained. A minimum soil depth of two feet is preferred.

25.07.08 Application Rates

For land application systems, the engineer shall consider sludge composition, soil characteristics, climate, vegetation, cropping practices and other critical factors in determining application rates. Since sludge and site factors vary widely, application rates shall be determined for each specific site. Application rates shall be approved by the Department and the Board.

Nitrogenous substances are usually the limiting factor in determining annual application rates. Unless it can be satisfactorily demonstrated that the nitrogen uptake of crops to be harvested justifies a higher loading rate, the initial design application rate shall not exceed five tons of dry weight solids/acre/year. Guidelines for allowable application rates for specific crops are presented in Appendix K. Additionally, Appendix K presents guidelines on maximum loadings of cadmium, maximum cumulative levels for metals and acceptable soil pH levels. For any site receiving only a single application of sludge not to be repeated for at least five years, the maximum allowable loading rate for the on-time application shall be 15 tons of dry weight solids/acre. The above notwithstanding, at no time shall sludge be applied to a depth greater than 0.5 inches in any single application procedure.

No crops should be removed by harvesting or grazing less than 30 days after the last application of sludge. Pasture should be clipped immediately prior to sludge application.

25.07.09 Groundwater Quality

Land application sites, landfills, sludge lagoons and sludge holding facilities shall be designed and operated so that the utilization of sludge does not result in groundwater quality changes. If the presently existing concentration of any parameter is high in the groundwater than the level allowed for a raw water supply source (reference: Commonwealth of Virginia Waterworks Regulations), then the sludge utilization or disposal technique shall not result in an increase in the concentration of that parameter.

25.07.10 Holding Facilities

a. Emergency Holding

Raw sludges, septic tank sludges, sludges from upset digesters and sludges of similar nature may be stored in emergency holding facilities. Subsequent processing of the supernatant and sludge shall be provided in an approved manner. Such holding facilities should be located remote from human activity. The engineer shall provide a plan for approval by the Department and the Board. The plan shall address sampling, odor control, vector control, potential soil and water pollution, and security.

b. Routine Holding

During periods when application of sludges to agricultural land is not possible due to climatic or other conditions, a holding facility shall be provided. The engineer shall provide a mass balance which determines the amount of sludge storage which is to be provided. The location and protection of the holding facility shall conform to the requirements stated in Section 25.07.01a, above. Holding shall be utilized to enhance runoff prevention.

25.07.11 Incineration

Incineration of sludges and screenings from treatment facilities is an approved method of solids reduction. Such facilities shall meet all requirements for air pollution control. The ash from such processes may be buried or spread on land selected for such purposes and approved by the Department and the Board.

25.07.12 Sludge Lagoons

a. Long Term Storage Lagoons

Long term storage lagooning of stabilized sludges is allowable if provisions are made for ultimate disposal of the sludge in accordance with the requirements of the section. Decant liquid from the lagoon shall be conveyed to a plant by an approved method for treatment in a manner that will not upset the plant's operational efficiency. Adequate provisions shall be made to prevent seepage from the lagoon. Fencing and warning signs shall be required.

b. Ultimate Disposal Lagoons

Lagooning of stabilized sludges as a means of ultimate disposal is allowable if stored in accordance with Section 25.07.12a above and covered with soil upon completion of use to a depth of two feet.

25.07.13 Transport of Sludge

The engineer shall furnish the final engineering documents (Section 2.03) the equipment and materials needed for sludge handling, including nonspill, water-tight vehicles for transport, routes, quantities of sludge and procedures to be used. Transport vehicles should be equipped with tow hooks, and transport routes through heavily populated areas should be avoided.

25.07.14 Land Reclamation

Land reclamation is an accepted practice usually utilizing high application rates of liquid sludge. Class A sludges are acceptable for land reclamation. The sludge utilization program shall be developed between the owner, the Department, the Board, the Division of Mined Land Reclamation (when appropriate) and other agencies as appropriate.

25.07.15 Other Methods

Other methods of sludge and solids disposal, such as preparation and use as a soil conditioner, will be considered on a case by case basis.

25.07.16 Runoff Prevention

An area which has sludge applied by spraying or spreading shall be located a minimum distance of 50 feet from all surface water. Containment and controlled release of runoff from sludge application areas or effective erosion control methods should be practiced as necessary.