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TITLE 30ENVIRONMENTAL QUALITY
PART 1TEXAS COMMISSION ON ENVIRONMENTAL QUALITY
CHAPTER 317DESIGN CRITERIA PRIOR TO 2008
RULE §317.1General Provisions

    (B) All reviews performed by an employee of the municipality shall be conducted by a professional engineer, registered in the State of Texas, or the employee conducting the review shall be under the direct supervision of a professional engineer, registered in the State of Texas, who is ultimately responsible for the review and approval of each collection system submitted and installed in the municipality's jurisdiction.

    (C) The responsible review engineer shall be either an employee of the reviewing municipality, or a consultant to the municipality, separate from the private consulting firm charged with the design work under review. For purposes of this section, the term "separate" means that the responsible review engineer is not employed by and does not receive compensation from the private consulting firm and from any of its parent companies, subsidiaries, or affiliates charged with the design. The municipality shall provide on request documentation of its agreements with private consultants sufficient to allow the agency to audit its compliance with this subsection.

    (D) A participating municipality may review and approve engineering reports, plans, and specifications only for projects which transport primarily domestic waste within the boundaries of jurisdiction of that municipality. For each project approved for construction, the municipality shall issue an approval letter or other indication of the approval which clearly details the project being approved.

    (E) The municipality shall maintain complete files of all review and approval activities carried out under its authority and shall make any existing project files available to the commission upon request and/or during audits performed in accordance with paragraph (6) of this subsection.

  (6) The executive director may perform periodic audits of the review and approval process of municipalities which perform technical reviews of sanitary sewer collection systems in lieu of the commission, to ensure that the projects approved by the municipalities are in compliance with this chapter. If the executive director decides to perform an audit of a municipality's review and approval process, the executive director will provide the municipality with a minimum of five working days advance notice of the pending audit. The executive director may, for auditing purposes only, review specific projects which have previously been approved by the review authority. The municipality shall provide to the executive director, on request, documentation of all agreements between the private consultants and the municipality, which relate to the wastewater collection system review program. If the executive director finds through reviews of specific projects or through audits of the municipality's review and approval process that a municipality's review and approval process does not provide for compliance with the minimum design and installation requirements detailed in this chapter, the review and approval authority shall address these findings within a time established by the executive director. If compliance cannot be achieved, the review authority shall be voided for that municipality. If such authority is voided for a municipality, the executive director shall notify the municipality in writing and shall include the justification for voiding the authority of the municipality. If the authority of a municipality is voided, all new projects proposed to be constructed within that municipality's jurisdiction shall be submitted to the executive director in accordance with paragraph (3)(D) of this subsection.

(b) Preliminary engineering report.

  (1) Definition. The preliminary engineering report shall form the conceptual basis for the collection, treatment, and/or disposal system proposed. This document shall bear the signed and dated seal of the registered professional engineer responsible for the design.

    (A) For projects receiving United States Environmental Protection Agency construction grants assistance, a facility plan may serve as the preliminary engineering report.

    (B) For all other projects, a preliminary engineering report proposing processes, methods, or procedures may be submitted as early in the planning stage as is practical. Submission of a preliminary engineering report at this point is only necessary to resolve any potential disagreements between the design engineer and the commission regarding the essential planning information, design data, population projections, and other requirements of the commission. Agreement is desirable to eliminate delays or inconveniences and to avoid the possibility of having to revise the final plans and specifications.

    (C) The preliminary engineering report may be merged directly with the final engineering report to produce a single engineering report at the discretion of the sewerage system owner.

  (2) General requirements. The following is required for each project as applicable.

    (A) A brief description of the project with maps showing the area to be served, general location of proposed improvements, water and wastewater treatment plant sites, existing and proposed streets, parks, drainage ditches, creeks, streams, and water mains shall be provided. The drainage area should be defined clearly, either by contour map or otherwise. Where a contour map is not available to the community, one should be obtained and the contours should be shown at intervals of not more than ten feet. The maps and plans shall be reproduced on paper not larger than 24 inches by 36 inches in size; however, where variations are necessary, all sheets shall be uniform in size.

    (B) The domestic population of the area to be served (present and projected) and design population of the project shall be included.

    (C) The names of industries contributing any significant wastes, types of industry (standard industry codes), volume of wastes, characteristics and strength of wastes, population equivalent, and other pertinent information shall be included. It should be emphasized that if significant amounts of wastes other than normal domestic sewage are to be treated at the wastewater treatment plant, sufficient data on such wastes must be presented to allow an evaluation of the effect on the treatment process. This would include, but not be limited to, heavy metals and toxic materials such as polychlorinated biphenyls, organic chemicals, and pesticides.

    (D) The preliminary engineering report shall include the technical information described in §317.10 of this title (relating to Appendix B--Overland Flow Process) for all overland flow projects.

  (3) Collection system. The following information shall be provided in the preliminary engineering report if applicable to the project:

    (A) present area served and future areas to be served;

    (B) terrain data in sufficient detail to establish general topographical features of present and future areas to be served;

    (C) lift stations existing and/or proposed;

    (D) effect of proposed system expansion on existing system capacity; and

    (E) amount of infiltration/inflow existing and anticipated, and how it is to be addressed in the collection system design.

  (4) Treatment plant. The following information is required in a preliminary engineering report.

    (A) Quantity and quality of existing sewage influent and changes in the characteristics anticipated in the future. If adequate records are not available, analyses shall be made for the existing conditions and such information included in the report.

    (B) Design and peak flow rates being considered and the design period. Design flow is defined as the wet weather maximum 30-day average flow. Therefore, when determining design flow rates, consideration must be given to flows during periods of wet weather in order to assure consistent compliance with discharge permit volume and quality limitations. Peak flow is defined as the highest two hour flow expected to be encountered under any operational conditions, including times of high rainfall (generally the two-year, 24-hour storm is assumed) and prolonged periods of wet weather. For new systems, the peak flow to average annual flow ratio is normally in the range of three-five to one, although other peaking factors may be warranted.

    (C) Type of treatment plant proposed and the effluent quality expected. The information should include basis of design, flow, organic loading, infiltration allowance, and efficiency determinations sufficient to a given level of treatment.

    (D) Type of units proposed and their capacities, considering the criteria contained herein. The information should include detention times, surface loadings, weir loadings, flow diagram, and other pertinent information regarding the design of the plant, including sludge processing units required for the selected ultimate sludge disposal.

    (E) Treatment plant site information and the siting analysis. The location of the plant, the area included in the plant site, dedicated buffer zone, and a description of the surrounding area including a map or a sketch of the area. Particular reference should be made as to the plant's proximity to present and future housing developments, industrial sites, prevailing winds, highways and/or public thoroughfares, water plants, water supply wells, parks, schools, recreational areas, and shopping centers. If the effluent is to be discharged to the waters of the state, the immediate receiving stream, canal, major water course, etc., shall be designated. The siting analysis shall include:

      (i) flood hazard analysis. Provide the 100-year flood plain elevation. Proposed treatment units which are to be located within the 100-year flood plain will not be approved for construction unless protective measures satisfactory to the commission (such as levees or elevation of the treatment units) are included in the project design;

      (ii) buffer zone analysis. Demonstrate that the location of each proposed treatment unit is consistent with the buffer zone criteria specified in Chapter 309 of this title (relating to Domestic Wastewater Effluent Limitation and Plant Siting).

  (5) Sludge management. The preliminary engineering report shall include a discussion of the method of sludge disposal to be utilized. The report shall assess the following factors:

    (A) estimated quantity of sludge that must be handled which includes future sludge loads based on flow projections;

    (B) quality and sludge treatment requirements for ultimate disposal;

    (C) sludge storage requirements for each alternative considering normal operating requirements and contingencies;

    (D) transportation of sludge;

    (E) land use and land availability; and

    (F) reliability of the various alternatives, contingencies, and mitigation plans to ensure reliable capacity and operational flexibility.

  (6) Control of bypassing. Information and data shall be submitted to describe features (auxiliary power, standby and duplicate units, holding tanks, storm water clarifiers, etc.) and operational arrangements (flexibility of piping and valves to control flow through the plant, reliability of power sources, etc.) to prevent unauthorized discharges of untreated or partially treated wastewater. An outline of control measures to prevent unauthorized discharges of untreated or partially treated wastewater during construction (see subsection (e)(5) of this section) is to be included.

(c) Final engineering design report. The final engineering design report shall be submitted with the final plans and technical specifications. The report shall include calculations and any other engineering information pertaining to the plant design as may be necessary in the review of the plans and specifications by the commission. The report must include how the design of the collection system and treatment plant will handle the potential loss of graywater as defined in TWC, §26.0311. This report shall bear the signed and dated seal of the registered professional engineer responsible for the design. Information should be included to describe any changes that have been made since a preliminary engineering report was submitted, along with additional information as follows.

  (1) Collection system (if applicable):

    (A) minimum and maximum grades proposed for each size and type of pipe;

    (B) lift stations (also refer to §317.3 of this title (relating to Lift Stations)):

      (i) the operating characteristics of the stations at minimum, maximum, and design flows (both present and future);

      (ii) safety considerations, such as ventilation, entrances, working areas, and prevention of explosions; and

      (iii) means of preventing overflow of raw sewage;

    (C) capability of existing trunk and interceptor sewers and lift stations to handle the peak flow under anticipated conditions and capability of existing treatment facilities to receive and adequately treat the anticipated peak flows;

    (D) type of pipe proposed and its anticipated performance under the conditions imposed by the particular wastewater quality and loading conditions;

    (E) the manhole spacing proposed;

    (F) areas not served by the present proposed project, and the projected means of providing service to these areas, including special provisions incorporated in the present plans for future expansion;

    (G) amount of infiltration/inflow existing and anticipated, its hydraulic effect on the proposed and existing system, and an abatement plan if applicable, including a:

Cont'd...

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