Nebraska Administrative Code
Topic - ENVIRONMENT AND ENERGY
Title 123 - NEBRASKA DEPARTMENT OF ENVIRONMENTAL QUALITY
Chapter 5 - DESIGN STANDARDS AND SPECIFICATIONS
Section 123-5-001 - General Design Criteria Requirements

001.01 Wastewater works will be designed in accordance with the design standards listed in this Title. Where specific standards are not included in this Title, the design engineer is to submit a proposed design to the Department for review and approval. The Department will consider approving designs that follow generally accepted engineering guidelines and standards published by national engineering societies, federal environmental agencies, public health boards, or in engineering textbooks used by accredited university engineering programs.

001.02 The hydraulic design of wastewater works will be based on historical flow records. In the absence of flow records, an average daily flow of at least 100 gallons per person per day from domestic sources is to be used. This includes a normal allowance for infiltration and inflow. Flow from commercial, institutional, and industrial sources is to be estimated from similar facilities that have historic flow records.

001.03 The organic loading rates used for designing wastewater treatment facilities is to be based on historical influent data, if at least one year of monthly sampling data exists. In the absence of such data, the design of wastewater treatment facilities are to use an organic loading rate of at least 0.17 pounds of five-day biochemical oxygen demand (BOD5) per person per day and a suspended solids loading rate of at least 0.20 pounds per person per day from domestic sources. The organic loading from commercial, institutional, and industrial sources is to be estimated from similar facilities that have loading records.

001.04 The design of discharging WWTF will be adequate to meet all NPDES permit limits. Flow measurement equipment and sampling locations will be included in the design as required to meet NPDES permit monitoring requirements.

001.05 The design of wastewater collection systems will not include overflow structures of any kind. The design of wastewater treatment facilities will not include passive or unvalved bypass structures that discharge to the ground surface or to waters of the state.

001.06 Wastewater works are to be designed to prevent untreated or partially treated wastewater from entering floodwaters of a 100-year flood and are to prevent floodwaters from entering the wastewater works. The deck of lift stations, the top of earthen dikes, and the top of all other structures designed to store, convey, or treat wastewater or sludge will be at least one foot above the 100-year flood elevation.

001.07 All WWTF are to have an alternative source of power to provide pumping of wastewater through the treatment facility. The alternative source of power will be adequate to pump the peak day flow rate. This requirement is to be met by either an engine generator or by a second independent electrical supply source. Storage and subsequent treatment may also be used to meet this requirement.

001.08 All WWTF that have disinfection units are to have backup power provided for the disinfection process.

001.09 Each WWTF is to be enclosed with a fence, unless exempted by the Department. Fences be at least 42-inches high and adequate to keep out grazing animals, if located in rural areas, or pets and unauthorized persons if located in public areas. Suitable warning signs are to be posted.

001.10 All weather access roads will be provided to wastewater works, as necessary, to maintain normal operations of the wastewater works.