Background. Sludge is a by-product of water and wastewater treatment operations. Sludge from biological treatment operations is sometimes referred to as wastewater biosolids. Before sludge can be disposed, it needs to be treated to a certain degree. The type of treatment needed depends on the disposal method proposed. The two most common disposal methods are landfilling and land application. DHEC regulates the disposal of sludge via its various permitting programs.
Programs. Dewatered sludge can be landfilled in a municipal landfill if it is not a hazardous waste and if it has been properly dewatered. When a wastewater operation wants to landfill its sludge, the applicable Bureau of Water permit for the treatment plant (e.g., NPDES) identifies the specific landfill as a permit condition. Outside of landfilling, land application of sludge is regulated under R.61-9.503 (Domestic Sewage Sludge) and R.61-9.504 (Industrial Sludge) by the Bureau of Water. Permitting sites for land application of sludge normally is governed by the application of sludge on the land for beneficial use (i.e., agronomic rate for nitrogen). The application rate, though typically governed by nitrogen, is set by evaluating a variety of relevant pollutants and setting a conservative application rate.
Beneficial use of sludge. The beneficial use of sludge can be carried out on private farmland as well as dedicated sites owned by the owner of the wastewater treatment facility.
Septage. Septage is the material removed from septic tanks and grease traps. By regulatory definition septage is a type of sewage sludge. Land application of septage is regulated by R.61-9.503. Persons wanting to land-apply septage must receive a land application permit (and possibly a wastewater construction permit depending on the application and handling processes proposed).
Regulation details. All publicly owned and privately owned treatment facilities treating domestic wastewater are regulated by federal regulations 40 CFR 503. 40 CFR 503 deals with use and disposal of domestic sludge. The Bureau has developed a state regulation (R61-9.503) based on the key elements of the federal regulation. The industrial sludge regulations are in Section 504 of Regulation 61-9 and there are no comparable federal regulations.
NPDES/ND Facilities For a new wastewater treatment facility or an expansion of an existing wastewater treatment facility, a report on the method of sludge disposal is part of the NPDES or ND permit application that is included in a preliminary engineering report (PER) submittal package. The sludge report must address the applicable criteria contained in Sections 503 and 504 of Regulation 61-9.
The method of sludge disposal is reviewed with the PER on the wastewater treatment facility. After approval of the PER, the NPDES or ND permit will be drafted with the method of sludge disposal contained in it. Therefore, the procedures for processing a new wastewater treatment facility or an expansion of an existing wastewater treatment facility will include sludge handling for the wastewater treatment facility. Contact Brenda Green for permitting assistance at firstname.lastname@example.org.
Industrial Pretreatment Facilities. For new or expanding industries with pretreatment systems that generate sludge, a report on the method of sludge disposal is included with the wastewater construction permit application on the pretreatment facility. When the method of sludge disposal is land application, a separate state land application system permit for the disposal of the sludge disposal must be issued before the state wastewater construction permit can be issued. When the method of sludge disposal is transporting to a landfill or other wastewater treatment facility, a letter of acceptance from the owner of the receiving facility must be included with the wastewater construction permit application package.