The following words and terms, when used in this chapter, have the following meanings unless the context clearly indicates otherwise.

1. (1) Advanced nutrient removal--A process to remove phosphorus and/or nitrogen and produce effluent of higher quality than normally achieved by secondary treatment processes.
2. (2) Alternative collection system--A system or combination of systems that collects wastewater and incorporates any of the following: pressure sewer, small diameter gravity sewer, or vacuum sewer that is not a conventional gravity collection system. An alternative collection system is comprised of both on-site and off-site components.
3. (3) Annual average flow--The arithmetic average of all daily flow determinations taken within a period of 12 consecutive months.
4. (4) Biotower--A biological filtration system that involves biological film on a plastic media that reduces the biological oxygen demand of the effluent.
5. (5) Building lateral--A pipe that conveys raw wastewater and connects the plumbing of a structure to an on-site component or a collection system pipe. A building lateral is privately owned and is not a part of a wastewater collection system.
6. (6) Bypass--The intentional diversion of a waste stream from any portion of a treatment facility.
7. (7) Collection system--Pipes, conduits, lift stations, force mains, and all other constructions, devices, and appurtenant appliances used to transport wastewater.
8. (8) Constructed Wetland--A water treatment facility built to duplicate the processes occurring in natural wetlands, which are complex, integrated systems in which water, plants, animals, microorganisms and the environment (sun, soil, and air) interact to improve water quality.
9. (9) Design flow--The average daily flow rate for a treatment facility permitted by the commission.
10. (10) Diurnal Flow--The daily cycle of high and low influent flows to a wastewater treatment system.
11. (11) Domestic Wastewater--Sewage that is characterized as residential wastewater, not produced by commercial or industrial activity, and which originates primarily from kitchen, bathroom, and laundry sources, including waste from food preparation, dishwashing, garbage grinding, toilets, baths, showers, and sinks of a residential dwelling.
12. (12) Effective size--The result of an analysis of a sample of filter media that equals the effective diameter, D10, which is the diameter of the particle size at 10% finer-by-weight as plotted on a semi-log grain size distribution curve. In other words, 10% of the sample particles are finer and 90% are larger than the effective size.
13. (13) Engineer--A professional engineer with expertise in wastewater design and construction licensed by the Texas Board of Professional Engineers.
14. (14) Equivalent dwelling unit--Any building or section of a building that produces wastewater of a composition and quantity comparable to that discharged by a single, private residence.
15. (15) Facility--All land, structures, operational units, or appurtenances used jointly to process, treat, and dispose of wastewater.
16. (16) Filter media--The material placed in a filter containment structure to perform the filtering action.
17. (17) Firm pumping capacity--The maximum flowrate under design conditions with the largest pumping unit out of service.
18. (18) Flat plate system--A membrane bioreactor that arranges membranes into rectangular cartridges with a porous backing material sandwiched between two membranes for structural support.
19. (19) Force main--A pressure-rated conduit that conveys wastewater from a pump station to a discharge point.
20. (20) Free water system--A constructed wetlands designed to have the water surface above the wetland bed or substrate.
21. (21) Grinder pump--A component that receives raw wastewater through a building lateral, grinds the solids in the wastewater into a slurry, and provides the motive force for transporting the raw wastewater to a lift station or a collection system.
22. (22) Gross flux rate--The volume of water that passes through a membrane measured in gallons per day per square-foot of membrane area at a standard temperature of 20 degrees Centigrade.
23. (23) Headworks--The location where wastewater enters a facility and the first chance to treat the flow, typically by removing large solids and grit.
24. (24) Hollow fiber system--A membrane bioreactor composed of bundles of very fine membrane fibers, approximately 0.5-2 millimeter diameter, held in place at the ends with hardened plastic potting material, and supported on stainless steel frames or rack assemblies. The outer surface of each fiber is exposed to the mixed liquor with filtrate flow from outside to inside through membrane pores.
25. (25) Innovative technology--A process not addressed in this chapter or a process specifically identified as innovative by this chapter.
26. (26) Interceptor tank--A component that receives raw wastewater from a building lateral, removes floatable and settleable solids, stores the removed solids, and provides flow attenuation.
27. (27) Lift station--A belowground structure that collects wastewater and utilizes pumps to raise it to a higher elevation. The term lift station applies to a structure in which the static head exceeds the frictional headlosses.
28. (28) Material alteration--a change to a collection system or treatment facility that changes efficiency of the collection system or treatment facility.
29. (29) Membrane bioreactor system--An activated sludge biological treatment system that uses membrane filtration rather than secondary clarification for solids separation and conventional filtration.
30. (30) Minimum grade effluent sewer--An alternative wastewater collection system pipeline with a constant downward slope.

31. (31) Multiple equivalent dwelling unit :

    1. (A) a group of residences served by a common service connection; or

    2. (B) a commercial, industrial, institutional, or other non-residential establishment that produces wastewater:

       1. (i) in excess of 1,500 gallons per day; or
       2. (ii) not comparable in composition to that discharged by a single private residence.
32. (32) Net flux rate--The gross flux rate adjusted for production lost during backwash, relaxation, and cleaning.
33. (33) Nonconforming technology--Technology or a process that does not conform to the design criteria of this chapter or a technology or process specifically identified as nonconforming by this chapter.
34. (34) Off-site component--A wastewater collection system component that includes collection system pipes, force mains, pump stations, lift stations, vacuum stations, and related appurtenances located outside a wastewater treatment facility's site boundary.
35. (35) On-site component--Equipment, structure, or pipe located within a wastewater treatment facility's site boundary.
36. (36) Overflow--A flow over the weir of a treatment unit.
37. (37) Owner--A person who owns a collection system or a treatment facility or part of a system or facility.
38. (38) Peak flow--The highest two-hour flow expected under any operational conditions, including times of high rainfall based on a two-year 24-hour storm or a prolonged period of wet weather.
39. (39) Pressure sewer--A wastewater collection system that is pressurized by pumps at each service connection.
40. (40) Project--A TCEQ permitted wastewater collection system or treatment facility on which construction has begun but that is not yet complete.
41. (41) Proposed facility--A TCEQ permitted wastewater treatment facility on which construction has not begun.
42. (42) Pump--A device that raises, transfers, or compresses fluids by suction, pressure, or both.
43. (43) Report--The final engineering design report prepared, signed, sealed by the design engineer that contains calculations and written descriptions of processes, equipment, and structures that demonstrate compliance with this chapter, as described in §217.10 of this title (relating to Final Engineering Design Report).

44. (44) Sequencing Batch Reactor (SBR)--A fill and draw activated sludge treatment system that is identical to conventional activated sludge systems, except the processes are carried out sequentially in the same tank. An SBR system has the following five steps that are carried out in the following sequence:

    1. (A) Fill--The basin is filled with the influent;
    2. (B) React--The influent in the basin is aerated;
    3. (C) Settle--The mixed liquor within the basin is settled (clarification);
    4. (D) Draw--The basin is decanted; and
    5. (E) Idle--The sludge is removed from the basin.
45. (45) Small diameter effluent sewer--A collection system that receives effluent from an interceptor tank, transports the flow by gravity, and may include minimum grade effluent sewers and variable grade effluent sewers.
46. (46) Transmembrane pressure--The difference between the average pressure on the feed side of a membrane and the average pressure on the permeate side of a membrane or the driving force associated with any given flux rate.
47. (47) Tubular system--A system in which sludge is pumped from an aeration basin to a pressure driven membrane system outside of a bioreactor where the suspended solids are retained and recycled back into the bioreactor while the effluent passes through a membrane.
48. (48) Variable grade effluent sewer--A small diameter gravity wastewater collection system that does not require a uniform gradient, but will allow inflective gradients where sections of the collection system are below the hydraulic grade line. May be used with septic tank effluent pumps.
49. (49) Variance--A deviation from a specific requirement of this chapter.
50. (50) Wastewater--A waterborne industrial waste, recreational waste, domestic waste, or combination of these wastes.
51. (51) Wasting--The practice of removing excess or old sludge from a wastewater treatment process.

Source Note:The provisions of this §217.2 adopted to be effective August 28, 2008, 33 TexReg 6843.