Industrial Pretreatment & Wastewater Laboratory Programs
As part of Wichita's NPDES Permit to discharge treated sewage to the Arkansas River, the City is required by the U.S. Environmental Protection Agency to implement and enforce the Federal Pretreatment Regulations which include pollutant discharge standards for categorical industries (e.g. Metal Finishers, Foundries, Circuit Board Manufacturers, Oil Refineries), as well as general regulations for all Significant Industrial Users (SIU).
The City regulates all local industries which discharge pollutants into the sanitary sewer that may cause any interference or damage to the municipal sewage conveyance and treatment system, or cause the City's sewage treatment plant to violate its NPDES Permit limitations.
These requirements place the City in the position of being a service provider and a regulator. The Wichita Water Utilities strives to perform both duties well, by providing excellent water and sewer service to its customers and by enforcing all Pretreatment Regulations in a fair and equitable manner.
To determine if an industrial process will be regulated by the City, first determine if the industry qualifies as a Significant Industrial User. If the industry meets the SIU criteria, then it must be issued an Industrial Wastewater Discharge Permit by the City. The Permit will contain conditions and requirements the industry must meet to maintain compliance with all Federal, State, and local Pretreatment Regulations.
General SIU criteria is as follows:
- The industry discharges at least 25,000 gallons per day of wastewater to the sanitary sewer.
- The industrial process is identified as one of the Federal Pretreatment Categorical Industries. For a list of categorical industries, contact the Pretreatment Office at (316) 303-8703.
- The industry discharges a pollutant which could cause interference or damage to the Publicly Owned Treatment Works (POTW) or negatively impacts the receiving waters upon discharge or sewage sludge disposal requirements.
- The industry discharges a waste stream which the Director of the Water & Sewer Department has reasonably determined requires issuance of an Industrial Wastewater Permit to Discharge.
All SIUs permitted by the City are subject to a permit fee which is based on the industrial wastewater daily flow rates. Your best course of action is to contact the City's Pretreatment Office at (316) 303-8703 and let them help you evaluate your need for a permit.
Extra Strength Sewage Billing Program
In has a sewage surcharge program called the Extra Strength Program. If the industry discharges waste which contains high concentrations of treatable pollutants, then the industry is sampled and billed on a monthly basis for the treatment of this "extra strength" waste. This assures that the treatment and disposal costs associated with wastewater with conventional pollutant concentrations higher than residential wastes, will be paid for by the industry rather than the residential customer. Conventional Pollutants billed by the Water and Sewer Department are:
- Biochemical Oxygen Demand
- Total Suspended Solids
- Oil and Grease
These are current inside the City rates and are assessed per pound per month based on the volume discharged and the analytical results of the samples collected during the monthly billing cycle. Outside the City rates are approximately 55% higher.
Sewer Service Usage and Billing
Your monthly sewer usage charge is based on the amount of City water consumed during the billing cycle. However, if the industry supplements its City water usage with well water and discharges the total to the sewer, then the industry must either meter the well water consumed or install a totalizing meter at the point of wastewater discharge into the City sewage collection system.
Many industries discharge less water than what is consumed, as a result of water going out in the product (e.g. commercial bakeries, soft drink manufacturers, concrete companies), or water evaporated during operations (e.g. boilers, cooling towers). In order to receive credit on the sewer bill, the industry must request that the City install a meter at the water which is not being discharged or request that the City install a meter a the point of wastewater discharge into the City sanitary sewer.
Grease Trap Requirements
The City of Wichita requires grease interceptor installations in food establishment sewer discharge lines. The approved ordinance requirements include:
- All new food service establishments must install an interceptor prior to connecting to the sanitary sewer system.
- Implementation of a grease interceptor inspection and maintenance program.
- Existing restaurants without an approved grease interceptor must pay a monthly fee to recover grease removal costs incurred by the City. If it is found that an existing facility causes significant grease discharges, the facility is required to install, operate and maintain an approved grease interceptor.
For more information regarding the City’s Food Grease control program, contact the Environmental Health Office - 268-8351.
Remedial Groundwater Discharge Program
Some facilities have contaminated groundwater which must be treated and discharged. The City prefers that these businesses seek other alternatives than the sanitary sewer to discharge the groundwater. However, as a temporary measure, the City may accept the treated groundwater if it meets Pretreatment Discharge Standards and capacity is available in the sanitary sewer. The discharge period is limited to a maximum five year term with annual permit renewals required. The business is required to monitor the discharge to assure that it meets pretreatment requirements. For Permit monitoring and fee requirements, contact the Pretreatment Office
Every day the Sewage Treatment Laboratory analyzes over 50 samples collected from various processes at the four wastewater facilities to assure that the plants are operating in full compliance with regulatory discharge requirements. The rivers and streams that receive the plants effluent discharges are also monitored. The laboratory must meet stringent laboratory certification criteria, and by doing so is certified by the National Environmental Laboratory Accreditation Program.
What are Biosolids
Biosolids are the nutrient-rich organic product of wastewater treatment. A beneficial resource, biosolids contain essential plant nutrient and organic matter and are recycled as a fertilizer and soil amendment.
Wastewater treatment processes are taken right out of nature's recipe book. In streams and lakes natural aeration helps to purify the water while microorganisms break down solids. Wastewater treatment uses the same idea; the liquid portion is treated and returned to streams, lakes, or oceans, and the solids are further processed into stable organic material, called biosolids.
Everyone contributes directly or indirectly to biosolids. Both businesses and households, whether connected to sewer systems or on septic tanks, generate biosolids. Today, modern treatment processes and strict controls on discharges to sewers contribute to high quality, recyclable biosolids.
The Public Works & Utilities Sewage Treatment Division operates a biosolids land application program which results in approximately 20,000 tons of biosolids applied annually on almost 500 acres of agricultural land that is used to raise crops such as corn, soybeans and wheat.
Biosolids contain essential plant macronutrients (used by plants in large amounts) including nitrogen, phosphorus and sulfur, as well as plant micronutrients (required in smaller amounts) such as zinc and copper. Applications of biosolids allow these nutrients to enter the soil for plant use. Biosolids are retained in the soil and release nutrients slowly as they are needed by plants. Appropriate applications of biosolids prevent nutrients from leaching beyond the plant rooting zone into the groundwater.
Biosolids applications promote plant root growth and generally help plants to grow greener, more vigorously and often with improved yields. The dense crops grown by biosolids create large amounts of straw and other organic matter that can be tilled back into the soil, improving soil moisture retention and erosion resistance, as well as increasing natural earthworm populations. Recent studies have shown that organic matter used in agriculture helps suppress plant disease. The addition of biosolids can also help to moderate highly alkaline or acidic soil conditions.
Biosolids have been recycled on pastureland, dryland wheat, soybean, and corn in area farmlands surrounding Wichita. Application rates are carefully designed to meet the needs of individual crops. Dewatered biosolids are typically applied with calibrated manure spreaders and tilled into the soil.