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Wastewater Operations
Joseph Majdalani, P.E., Senior Assistant Director
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Wastewater Effluent |
Wastewater FAQ’s
Answers to Wastewater Treatment FAQ’s:
- Treatment plants remove impurities contained in wastewater. This treated water can then be safely discharged to the environment. This same process occurs in nature. Treatment plants enhance this natural process and speed it up to treat larger volumes of wastewater in a shorter period of time. Treatment includes physical, biological and chemical processes to reclaim the water.
- Your grandparents had to worry about typhoid, cholera and other infectious diseases that are carried in raw sewage. Wastewater treatment systems serve primarily to protect the health of the general population by insuring that water sources remain clean. In today's world, people live a lot longer and in higher concentrations resulting in increased volumes of raw sewage. Modern wastewater treatment systems are critical to a safer, cleaner environment by reducing the organic load, and controlling bacteria and waterborne diseases.
- The City of Houston's Wastewater Treatment Facilities are regulated by the United States Environmental Protection Agency (USEPA) and the Texas Commission for Environmental Quality (TCEQ). These agencies perform random testing of the facilities' effluent. The USEPA, through the TCEQ, issues a National Pollutant Discharge Elimination System (NPDES) Permit. Included in the TPDES permit are specific guidelines concerning the testing of the facilities' effluent. The City of Houston performs lab analyses 5 days-a-week, which is significantly more frequent than the NPDES permit requires. Our facilities average 2 Mg/L BOD and 4 Mg/L suspended solids in their effluent, or 10% and 20% respectively, of the allowable maximum limits under the City’s NPDES permit.
- Reclaimed water from all of Houston wastewater plants is discharged directly into a surface waterway, usually one of the area bayous.
- The City operates forty Wastewater Treatment Plants, including five classified as Major Plants and thirty-five classified as Satellite Plants. In addition, the City of Houston also operates three Wet Weather Facilities. The wet weather facilities are operated during storm events when either the treatment plant or collection system becomes overwhelmed with additional water generated by the storm event. Plants are located in various areas throughout the City. The largest Wastewater Treatment Plant in Houston is the 69th Street Plant.
- Plant tours can be requested and are usually conducted at the 69th Street facility, mentioned above. For more information, or to schedule a tour, call 713-671-4208.
- Call City of Houston Information Line at 311 or the Wastewater Operations Control Center at 713-641-9955.
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FAQ’s - Wastewater Collection System Operations
Answers to Collection System Operations FAQ’s:
- Call 3-1-1, the City of Houston’s Utility Operations Center.
- The wastewater collection system is a system of pipes that transport wastewater (also called sanitary sewer) from a source, such as a residence, commercial business, or industrial plant, to a wastewater treatment plant. The wastewater treatment plant properly treats the wastewater so that it is safe to
- discharge to the environment.
 A private lateral is that part of the collection system that connects the resident’s house to the City’s wastewater main line. It is located on the resident’s property and it is the responsibility of the resident to service and to maintain the private lateral.
Easements are set aside for installation and maintenance by public and private utility operators. Sanitary Sewer Easement is needed for the maintenance, repair or rehabilitation of the sanitary sewers. Encroachments limit the City's ability to maintain, repair or rehabilitate sanitary sewers.
- Community sewers are a special case of back-lot sewers. These lateral sewers were installed at random throughout multiple parcels of property. These are most common in older developments. Community sewers were installed by connecting many homes through a single tap on the sanitary sewer main. They were generally installed across many properties, even under homes, before entering the public right-of-way. These community sewers cannot be maintained, rehabilitated, or replaced. To ensure continued wastewater collection, the community sewers must be replaced in the street right-of-way with new construction. Community sewers are not owned or maintained by the City. Problems that occur with Community sewers are the responsibility of the residents sharing that pipe.
- A sanitary sewer (or wastewater) clean-out is a plumbing fixture that allows access to the resident’s private lateral or the City’s wastewater main line.
- The clean-out is located on the resident’s property outside of the house foundation on the sanitary sewer service line. It is in line with the City’s sanitary sewer main line, which can be in front or in back of the house.
- The clean-out will be a 4” or 6” pipe with a threaded cap that may be freestanding, or set in concrete or a meter box.
- Unscrew the cap with a pipe wrench, channel-lock pliers, or a large crescent wrench.
- If there is a backup or overflow in the resident’s home and the clean-out on the private lateral is dry, the stoppage must be the plumbing inside the resident’s home. It is the responsibility of the resident to fix the problem.
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- If there is a backup or overflow at the residence and the clean-out is holding water or overflowing, the stoppage may be in the City’s main line. Call the City of Houston at 3-1-1. If the stoppage is determined not to be in the City’s main line, then the stoppage will be in the resident’s private lateral. It is the responsibility of the resident to fix the problem.
- Most sanitary sewer backups or overflows are caused by fats, oils, or grease being put into the sink. Residents can prevent backups and overflows by disposing of fats, oils, and grease in the garbage and avoiding the use of the garbage disposal to put foods down the drain. Vegetables, meat scraps, butter, cooking oils, and many other foods deposit grease and solids that can build up in pipes eventually creating blockages. The fats, oils, and grease harden when they go down the drain and clog pipes in the same manner that cholesterol clogs arteries in humans. Instead of putting food waste into a garbage disposal, scrape food waste from plates and pans into the garbage. Let melted oils used for cooking solidify in a container before placing them in the garbage. For more specific information on this, visit the City of Houston’s Corral the Grease website at www.corralthegrease.org. Sanitary sewer backups and overflows are also caused by roots or collapsed service pipes. Know where your private lateral is located and avoid planting trees and shrubs near it. Roots can creep into the sewer pipe joints and eventually cause a blockage. The best way to remove roots is to call a professional sewer cleaning service. The service pipe may need to be replaced if the pipe is cracked or collapsed.
- Call 3-1-1, the City of Houston’s Utility Operations Center.
- Sanitary sewer backups and overflows are harmful to humans and the environment because of the pollutants contained in it. When sanitary sewer overflows, contaminants are released into the environment. Untreated wastewater is harmful to humans because these contaminants can spread disease or pollute the waterways. They are harmful for the environment because they deplete oxygen in streams that fish and aquatic wildlife need to survive.
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- If you are going to dig on your property, please call Texas One-Call at 1-800-245-4545.
- For an Industrial Discharge Permit, contact Bob Hunt at 281-575-2824.
- Commercial establishments, such as restaurants, institutional cafeterias and other public kitchens, are regulated by City ordinance. They are required to install grease traps that must be cleaned periodically. Residents don't have grease traps under the City of Houston’s 2007 Code of Ordinances. The most practical way to reduce grease from residential kitchens is to prevent grease from entering the sewer pipes in the first place.
- The City of Houston’s Wastewater Collection System includes over 6,000 miles of pipes and 420 lift stations (pump stations to move wastewater from lower to higher elevation).
- You may contact the Collection System Operations at:
4545 Groveway
Houston, TX 77087
(713) 641-9956 (Phone)
(713) 644-3005 (Fax)
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Wastewater Pretreatment/Industrial Waste Service
Answers to Pretreatment/Industrial Waste FAQ’s:
- Industrial facilities and certain commercial facilities which plan to discharge industrial waste to the City's sanitary sewer system may be required to obtain an Industrial Waste Permit. For our purposes, Industrial Waste is defined as:
"Any waterborne solid, liquid or gaseous waste, resulting from any production, industrial, manufacturing or food processing operation or from the development, recovery or processing of any natural resource, including waste that is required to be pretreated by Chapter 47, Article V or the City's Plumbing Code."
You do not need an Industrial Waste Permit if:
- Your business is a self-service or commercial (not industrial) laundry.
- Your business is a restaurant.
- Your business is a car or truck wash where exteriors are being washed.
Additionally, the City of Houston is not currently requiring an Industrial Waste Permit for the following operations: Hospitals, analytical and research laboratories, small photographic developing operations, printers, and industries with wash racks that are used for routine equipment cleaning.
However, any facility discharging industrial waste to the sanitary sewer system may be required to obtain an Industrial Waste Permit if the Industrial Wastewater Service makes that determination.
Steps to Obtaining a Permit
- The first step in obtaining an Industrial Waste Permit is to contact the Industrial Wastewater Service at (281) 575-2800 to discuss your firm's operations and request an inspection of your facility.
- Once the City performs an inspection, and it has been determined your firm will require an Industrial Waste Permit, the City will send written notification that will include a permit application.
- After submitting your permit application to the City, the Industrial Wastewater Service will review it and, if the application is acceptable, an Industrial Waste Permit will be issued. All facilities required to obtain an Industrial Waste Permit must pay a permit/application fee of $75.00. The Industrial Waste Permit is issued for two (2) years and permits are renewable (after that period of time) for $75.00.
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- Significant Industrial Users
The term Significant Industrial User (SIU) applies to an industry that discharges to the sanitary sewer if that industry meets the following criteria:
- 1. The industry is subject to federal regulations.
- 2. Any other industrial user that discharges an average of 25,000 gallons per day or more of process wastewater to the POTW (excluding sanitary, non-contact cooling and boiler blow down wastewater); contributes a process waste stream which makes up 5 percent or more of the average dry weather hydraulic or organic capacity of the POTW treatment plant; or is designated as such by the control authority as defined in 40 CFR 403.12 (a) on the basis that the industrial user has a reasonable potential for adversely affecting the POTW operation or for violating any pretreatment standard or requirement.
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- SIUs are further classified as Categorical Industrial Users (CIU) if they are subject to federal discharge limitations developed by the EPA. CIUs are also subject to the City's local limits. All other SIUs are classified as Non- Categorical SIUs and are subject only to the City's local sanitary sewer discharge limits. SIUs are subject to more stringent rules than other types of businesses.
- Local Limits
Houston enforces local limits, as mandated by the EPA and the Clean Water Act. The City also enforces guidelines set forth in City of Houston Ordinance Article V., City Code Sections 47-186 through 47-208-which gave the City enforcement authority over permit violations. Section 47-194 (Standard of Quality) establishes the discharge limits as set out below.
Pollutant |
Grab Limit
(mg/L) |
Composite Limit
(mg/L) |
Arsenic |
3.0 |
2.0 |
Cadmium |
0.4 |
0.2 |
Chromium |
3.0 |
1.0 |
Copper |
3.0 |
2.0 |
Lead |
1.5 |
1.0 |
Mercury |
0.02 |
0.01 |
Nickel |
3.0 |
2.0 |
Selenium |
5.0 |
3.0 |
Silver |
2.0 |
1.0 |
Zinc |
6.0 |
3.0 |
Cyanide (Amenable) |
2.0 |
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Oil and Grease |
400.0 |
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Other Prohibited Discharges
- Acids with a pH value lower than 5 or alkalis with a pH higher than 11.
- Sulfides in concentrations greater than five (5) milligrams per liter
- Any liquid or vapor with a temperature exceeding 45 degrees Celsius (113 degrees Fahrenheit).
- Waste streams with a closed cup fIash point of less than 140 degrees Fahrenheit or 60 degrees Celsius.
- Any flammable or explosive liquid, solid, or gas
- Any discharge that forms a discernable floating layer of oil and grease on the surface of the discharged water.
- Sulid or viscous substances capable of obstructing flow in sewers.
- Any noxious substance that can form an objectionable or hazardous gas.
- Petroleum oil, non-biodegradable cutting oil, or products of mineral origin in amounts that cause interference with or passes through the sanitary sewer system.
- Pollutants resulting in toxic vapors, gases, or fumes that may cause acute utility worker health and safety problems.
- Any trucked or hauled waste except where the utility official has permitted a designated discharge point.
- Unusual concentrations of BOD, suspended solids or total dissolved solids such as sodium chloride or sodium sulfate.
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- Prohibited Wastes
There are certain prohibited wastes in general that should not be discharged under any circumstances, regardless of your pretreatment classification. They are
- Flammable, reactive, explosive, corrosive, or radioactive substances.
- Noxious or malodorous materials.
- Medical or infectious wastes
- Solid or viscous materials which could cause obstruction to the flow or operation of the treatment plants.
- Toxic substances
- Non-biodegradable oils
- Pollutants which result in the emission of hazardous gases.
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- Sanitary Sewer Surcharge on High Strength Waste
A sanitary sewer surcharge is imposed on an industrial user for discharges containing concentrations of Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS) exceeding acceptable values. If an industry's average BOD concentration exceeds 350 milligrams per liter, or if the average TSS concentration exceeds 375 milligrams per liter, the City will use a predetermined formula to calculate a sanitary sewer surcharge for wastewater billing. The Industrial Wastewater Service will perform an annual evaluation to determine what each permitted industry's sanitary sewer billing rate should be. The average concentrations for BOD and TSS from both City and industry self-monitoring are used to arrive at a sewer-billing rate. The surcharge fee pays for the cost of the additional treatment at the City's wastewater treatment plant. Treatment and removal of "high-strength" waste requires extra operating expenses such as the cost of additional chemicals, power, solids storage capacity, and final disposal.
- Enforcement of Pretreatment Guidelines
Industrial facilities which do not comply with permit requirements are subject to enforcement action. Houston utilizes a progressive enforcement response plan with actions ranging from issuance of Notices of Violation (NOVs) and Administrative Orders to sewer or water service termination and administrative fines. The key to responding to a violation notice is communication with the Industrial Wastewater Service.
- Federally Regulated Industrial Categories The following is a list of the federal categorical regulations that establish effluent limits for industries that discharge industrial waste to the sanitary sewer. If an industry performs a specific operation that is listed in one of the following categorical regulations, that industry is identified as a categorical industry. New categorical regulations are currently being developed by the EPA and this list should not be used to determine if these are the only categorical regulations that have been promulgated.
- Aluminum Forming (40 CFR 467)
- Asbestos Manufacturing (40 CFR 427)
- Battery Manufacturing (40 CFR 461)
- Coil Coating, Phase I (40 CFR 465)
- Coil Coating, Phase 11- Can Making Subcategory (40 CFR 465)
- Copper Forming (40 CFR 468)
- Electrical and Electronic Components, Phase land Phase II (40 CFR 469)
- Electroplating (40 CFR 413)
- Fertilizer Manufacturing (40 CFR 418)
- Glass Manufacturing (40 CFR 426)
- Ink Formulating (40 CFR 447)
- Iron and Steel (40 CFR 420)
- Leather Tanning and Finishing (40 CFR 425)
- Metal Finishing (40 CFR 433)
- Metal Molding and Casting (40 CFR 464)
- Nonferrous Metals Forming and Metal Powders (40 CFR 471)
- Nonferrous Metals Manufacturing, Phase I and II (40 CFR 421)
- Organic Chemicals, Plastics, and Synthetic Fibers (40 CFR 414)
- Paint Formulating (40 CFR 446)
- Pesticide Chemical Manufacturing (40 CFR 455)
- Petroleum Refining (40 CFR 419)
- Pharmaceutical Manufacturing (40 CFR 439)
- Porcelain Enameling (40 CFR 466)
- Pulp, Paper, and Paperboard and the Builder's Paper and Board Mills (40 CFR 430 and 431)
- Rubber Manufacturing (40 CFR 428)
- Soap and Detergent Manufacturing (40 CFR 417)
- Steam Electric Power Generation (40 CFR 423)
- Textile Mills (40 CFR 410)
- Timber Products (40 CFR 429)
- Transportation and Equipment Cleaning (40 CFR 442)
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