10 States Standards - Recommended Standards for Wastewater Facilities

In 1947, a "Committee on Development of Uniform Standards for Sewage Works" was created by the group now known as the Great Lakes -- Upper Mississippi River Board of State and Provincial Public Health and Environmental Managers.

This Committee, composed of a representative from each state, was assigned the responsibility to review existing standards for sewage works, to investigate the possibility of preparing joint standards to be adopted by the states represented, and to report its findings to the Board.

Based on this initial report, the Board authorized the Committee to prepare sewage works design standards, which were first published in 1951. They subsequently were revised and published again in 1960, 1968, 1971, 1973, 1978, 1990 and 1997. In 1977, the Province of Ontario was invited, as a Great Lakes participant, to serve on the Committee.

These standards have again been revised and are published herein as the 2004 edition. They are intended for use as a guide in the design and preparation of plans and specifications for wastewater facilities insofar as these standards are applicable to normal situations for an individual project.

The design criteria in these standards are intended for the more conventional municipal wastewater collection and treatment systems. Innovative approaches to collection and treatment, particularly for the very small municipal systems, are not included. The individual reviewing authority should be contacted for design guidance and criteria where such systems are being considered.

Lack of description or criteria for a unit process or equipment does not suggest it should not be used, but only that consideration by the reviewing authority will be on the basis of information submitted with the design. Engineering data that may be required for new process and application evaluation is included in Paragraph 53.2 of these standards.

These standards are intended to suggest limiting values for items upon which an evaluation of the plans and specifications will be made by the reviewing authority; and to establish, as far as practicable, uniformity of practice among the several states and province. Statutory requirements, regulations, and guidelines among the states and province are not uniform and use of the standards must adjust itself to these variations. Users also should be cognizant of locally adopted standards and applicable federal requirements.

The term "shall" is used where practice is sufficiently standardized to permit specific delineation of requirements or where safeguarding of the public health or protection of water quality justifies such definite action. Other terms, such as "should," "recommended," and "preferred," indicate desirable procedures or methods, with deviations subject to individual consideration.

Definition of terms and their use in these standards is intended to be in accordance with GLOSSARY -- WATER AND WASTEWATER CONTROL ENGINEERING, jointly prepared by APHA, ASCE, AWWA, and WPCF. The customary units of expression used are in accordance with those recommended in WPCF Manual of Practice No. 6, UNITS OF EXPRESSION FOR WASTEWATER MANAGEMENT. The International Standard Units are in accordance with those recommended in National Institute of Standards and Technology (NIST) Guide for the Use of the International System of Units (SI).

CHAPTER 10

ENGINEERING REPORTS AND FACILITY PLANS

10. GENERAL

10.1 Engineering Services

Engineering services are performed in three steps:

a. Engineering Report or Facility Plan;

b. Preparation of construction plans, specifications, and contractual documents; and

c. Construction compliance, inspection, administration, and acceptance.

Chapter 10, Engineering Reports and Facility Plans, covers only item a. above.

10.2 Preliminary Project Submittal

A preliminary project submittal may be necessary prior to preparation of an Engineering Report or Facility Plan. This submittal needs to include:

a. A description of problems or developments which have resulted in consideration of a wastewater facilities project;

b. Identification of governmental and consultant representatives authorized to provide information and seek regulatory agency approvals and decisions regarding the project; and

c. Identification of potential treated wastewater discharge locations for the purpose of regulatory agency determinations of suitable effluent quality requirements.

No approval for construction can be issued until final, detailed plans and specifications have been submitted and approved by the appropriate reviewing authority. Refer to Chapter 20.

11. ENGINEERING REPORT OR FACILITY PLAN

For federal, provincial, or state financed grant or loan projects, additional requirements may apply.

The Engineering Report or Facility Plan: identifies and evaluates wastewater related problems; assembles basic information; presents criteria and assumptions; examines alternate projects, with preliminary layouts and cost estimates; describes financing methods, sets forth anticipated charges for users; reviews organizational and staffing requirements; offers a conclusion with a proposed project for client consideration; and outlines official actions and procedures to implement the project. The planning document must include sufficient detail to demonstrate that the proposed project meets applicable criteria.

The concept (including process description and sizing), factual data, and controlling assumptions and considerations for the functional planning of wastewater facilities are presented for each process unit and for the whole system. These data form the continuing technical basis for the detailed design and preparation of construction plans and specifications.

Architectural, structural, mechanical, and electrical designs are usually excluded. Sketches may be desirable to aid in presentation of a project. Outline specifications of process units, special equipment, etc., are occasionally included.

Engineering Reports must be completed for minor collection system, pump station, and interceptor projects. Comprehensive Facility Plans must be completed or have been completed for projects involving new, expanded, upgraded, or rehabilitated wastewater treatment facilities and major collection, interceptor sewer, and pump station projects. The determination of classification as major or minor collection interceptor sewer and pump station projects will be made by the reviewing authority based on review of recommended classification by the owner.

11.1 Engineering Reports

Engineering reports shall contain the following and other pertinent information as required by the reviewing authority:

11.11 Problem Defined

Description of the existing system should include an evaluation of the conditions and problems needing correction.

11.12 Flow and Organic Load

The anticipated design average and design peak flows and waste load for the existing and ultimate conditions must be established. The basis of the projection of initial and future flows and waste load must be included and must reflect the existing, or initial service area, and the anticipated future service area. Flow and organic load information and data needed for new facilities are included in Paragraphs 11.24 and 11.25.

11.13 Impact on Existing Wastewater Facilities

The impact of the proposed project on all existing wastewater facilities, including gravity sewers, lift stations, and treatment facilities must be evaluated.

11.14 Project Description

A written description of the project is required.

11.15 Drawings

Drawings identifying the site of the project and anticipated location and alignment of proposed facilities are required.

11.16 Engineering Criteria

Engineering criteria to be used in design of the project shall be included.

11.17 Site Information

Project site information should include topography, soils, geologic conditions, depth to bedrock, groundwater level, floodway or floodplain considerations, and other pertinent site information.

11.18 Alternative Selection

The reasons for selection of the proposed alternative, including any lift station sites, feasibility, and how the project fits into a long term plan, should be discussed.

11.19 Environmental Review

Consideration should be given to minimizing any potential adverse environmental effects of the proposed project. If appropriate, compliance with planning requirements of federal, provincial, state, and local regulatory agencies shall be documented.

11.2 Facility Plans

Facility Plans shall contain the following and other pertinent information as required by the reviewing authority.

11.21 Problem Evaluation and Existing Facility Review

a. Descriptions of existing system including condition and evaluation of problems needing correction.

b. Summary of existing and previous local and regional wastewater facility and related planning documents.

11.22 Planning and Service Area

Planning area and existing and potential future service area.

11.23 Population Projection and Planning Period

Present and predicted population shall be based on a 20 year planning period. Phased construction of wastewater facilities should be considered in rapid growth areas. Sewers and other facilities with a design life in excess of 20 years should be designed for the extended period.

11.24 Hydraulic Capacity

11.241 Flow Definitions and Identification

The following flows for the design year shall be identified and used as a basis for design for sewers, lift stations, wastewater treatment plants, treatment units, and other wastewater handling facilities. Where any of the terms defined in this Section are used in these design standards, the definition contained in this Section applies.

a. Design Average Flow

The design average flow is the average of the daily volumes to be received for a continuous 12 month period expressed as a volume per unit time. However, the design average flow for facilities having critical seasonal high hydraulic loading periods (e.g., recreational areas, campuses, industrial facilities) shall be based on the daily average flow during the seasonal period.

b. Design Maximum Day Flow

The design maximum day flow is the largest volume of flow to be received during a continuous 24 hour period expressed as a volume per unit time.

c. Design Peak Hourly Flow

The design peak hourly flow is the largest volume of flow to be received during a one hour period expressed as a volume per unit time.

d. Design Peak Instantaneous Flow

The design peak instantaneous flow is the instantaneous maximum flow rate to be received.

11.242 Hydraulic Capacity for Wastewater Facilities to serve Existing Collection Systems

a. Projections shall be made from actual flow data to the extent possible.

b. The probable degree of accuracy of data and projections shall be evaluated. This reliability estimation should include an evaluation of the accuracy of existing data, as well as an evaluation of the reliability of estimates of flow reduction anticipated due to infiltration/inflow (I/I) reduction or flow increases due to elimination of sewer bypasses and backups.

c. Critical data and methodology used shall be included. It is recommended that graphical displays of critical peak wet weather flow data (refer to Paragraphs 11.241(b) (c) and (d)) be included for a sustained wet weather flow period of significance to the project.

11.243 Hydraulic Capacity for Wastewater Facilities to serve New Collection Systems

a. The sizing of wastewater facilities receiving flows from new wastewater collection systems shall be based on an average daily flow of 100 gallons (380 L) per capita plus wastewater flow from industrial plants and major institutional and commercial facilities unless water use data or other justification upon which to better estimate flow is provided.

b. The 100 gal/cap/d [380 L/(capita·d)] figure shall be used which, in conjunction with a peaking factor from Figure 1, is intended to cover normal infiltration for systems built with modern construction techniques. Refer to Section 31. However, an additional allowance should be made where conditions are unfavorable.

c. If the new collection system is to serve existing development the likelihood of I/I contributions from existing service lines and non-wastewater connections to those service lines shall be evaluated and wastewater facilities designed accordingly.

11.244 Combined Sewer Interceptors

In addition to the above requirements, interceptors for combined sewers shall have capacity to receive sufficient quantity of combined wastewater for transport to treatment facilities to ensure attainment of the appropriate water quality standards.

11.25 Organic Capacity

11.251 Organic Load Definitions and Identification

The following organic loads for the design year shall be identified and used as a basis for design of wastewater treatment facilities. Where any of the terms defined in this Section are used in these design standards, the definition contained in this Section applies.

a. Biochemical Oxygen Demand Defined

The 5-day Biochemical Oxygen Demand (BOD₅) is defined as the amount of oxygen required to stabilize biodegradable organic matter under aerobic conditions within a five day period in accordance with Standard Methods for the Examination of Water and Wastewater. Total 5-day Biochemical Oxygen Demand (TBOD₅) is equivalent to BOD₅ and is sometimes used in order to differentiate carbonaceous plus nitrogenous oxygen demand from strictly carbonaceous oxygen demand.

The carbonaceous 5-day Biochemical Oxygen Demand (CBOD₅) is defined as BOD₅ less the nitrogenous oxygen demand of the wastewater. See Standard Methods for the Examination of Water and Wastewater.

b. Design Average BOD₅

The design average BOD₅ is generally the average of the organic load received for a continuous 12 month period for the design year expressed as weight per day. However, the design average BOD₅ for facilities having critical seasonal high loading periods (e.g., recreational areas, campuses, industrial facilities) shall be based on the daily average BOD₅ during the seasonal period.

c. Design Maximum Day BOD₅

The design maximum day BOD₅ is the largest amount of organic load to be received during a continuous 24 hour period expressed as weight per day.

d. Design Peak Hourly BOD₅

The design peak hourly BOD₅ is the largest amount of organic load to be received during a one hour period expressed as weight per day.

11.252 Design of Organic Capacity of Wastewater Treatment Facilities to Serve Existing Collection Systems

a. Projections shall be made from actual wasteload data to the extent possible.

b. Projections shall be compared to Paragraph 11.253 and an accounting made for significant variations from those values.

c. Impact of industrial sources shall be documented. For projects with significant industrial contributions, evidence of adequate pretreatment strategies must be included along with documentation that industries are aware of the pretreatment limitations and user costs associated with the project. Documentation of the individual industrial participation in the project plan including user charges shall be provided.

d. Septage and leachate may contribute significant organic load and other materials which can cause operational problems and non-compliance with NPDES permit limitations. If septage or leachate are to be discharged to the wastewater treatment facility, consult the state regulatory agency and the Appendix, Handling and Treatment of Septage at a Wastewater Treatment Plant.

11.253 Organic Capacity of Wastewater Treatment Facilities to Serve New Collection Systems

a. Domestic waste treatment design shall be on the basis of at least 0.17 pounds (0.08 kg) of BOD₅ per capita per day and 0.20 pounds (0.09 kg) of suspended solids per capita per day, unless information is submitted to justify alternate designs.

b. Where garbage grinders are commonly used in areas tributary to a domestic treatment plant, the design basis should be increased to 0.22 pounds (0.10 kg) of BOD₅ per capita per day and 0.25 pounds (0.11 kg) of suspended solids per capita per day.

c. Industrial contributions. Refer to Paragraph 11.252(c).

d. Septage and Leachate. Refer to Paragraph 11.252(d).

e. Data from similar municipalities may be utilized in the case of new systems. However, thorough investigation that is adequately documented shall be provided to the reviewing authority to establish the reliability and applicability of such data.

11.26 Wastewater Treatment Facility Design Capacity

The wastewater treatment facility design capacity is the design average flow at the design average BOD₅. Refer to Paragraphs 11.24 and 11.25 for peaking factors that will be required.

11.27 Initial Alternative Development

The process of selection of wastewater treatment alternatives for detailed evaluation should be discussed. All wastewater management alternatives considered, including no action, and the basis for the engineering judgement for selection of the alternatives chosen for detailed evaluation, should be included.

11.28 Detailed Alternative Evaluation

The following shall be included for the alternatives to be evaluated in detail.

a. Sewer System Revisions

Proposed revisions to the existing sewer system including adequacy of portions not being changed by the project.

b. Wet Weather Flows

Facilities to transport and treat wet weather flows in a manner that complies with state and local regulations must be provided.

c. Site Evaluation

When a site must be used which is critical with respect to these items, appropriate measures shall be taken to minimize adverse impacts.

1. Compatibility of the treatment process with the present and planned future land use, including noise, potential odors, air quality, and anticipated sludge processing and disposal techniques, shall be considered.

Non-aerated lagoons should not be used if excessive sulfate is present in the wastewater.

Wastewater treatment facilities should be separate from habitation or any area likely to be built up within a reasonable future period and shall be separated in accordance with state and local requirements.

2. Zoning and other land use restrictions shall be identified.

3. An evaluation of the accessibility and topography of the site shall be submitted.

4. Area for future plant expansion shall be identified.

5. Direction of prevailing wind shall be identified.

6. Flood considerations, including the 25 and 100 year flood levels, impact on floodplain and floodway, and compliance with applicable regulations regarding construction in flood-prone areas, shall be evaluated. Paragraph 51.2 contains requirements for protection from flooding.

7. Geologic information, depth to bedrock, karst features, or other geologic considerations of significance to the project shall be included. Lagoons shall not be located in karst areas unless the specific geologic and construction details are acceptable.

8. Protection of groundwater including public and private wells is of utmost importance. Demonstration that protection will be provided must be included. The regulatory agency shall be contacted for required separation.

9. Soil type and suitability for construction and depth to normal and seasonal high groundwater shall be determined.

10. The location, depth, and discharge point of any field tile in the immediate area of the proposed site shall be identified.

11. Present and known future effluent quality requirements determined by the regulatory agency shall be included.

12. Access to receiving stream for the outfall line shall be discussed and displayed.

13. A preliminary assessment of site availability shall be included.

d. Unit Sizing

Unit operation and unit process sizing and basis shall be provided.

e. Flow Diagram

Flow diagram of treatment facilities including all recycle flows.

f. Emergency Operation

Emergency operation requirements as outlined in Section 46 and Paragraph 56.1 shall be provided. State or local regulatory agencies may have more stringent requirements.

g. Technology Not Included In These Standards

Paragraph 53.2 outlines procedures for introducing and obtaining approval to use technology not included in these standards. Proposals to use technology not included in these standards must address the requirements of Paragraph 53.2.

h. Sludge

The solids disposal options considered and method selected must be included. This is critical to completion of a successful project. Compliance with requirements of Chapter 80, Sludge Processing, Storage, and Disposal must be assured.

i. Treatment During Construction

A plan for the method and level of treatment to be achieved during construction shall be developed and included in the facility plan that must be submitted to the regulatory agency for review and approval. This approved treatment plan must be implemented by inclusion in the plans and specifications to be bid for the project. Refer to Paragraph 20.15 and Section 21.

j. Operation and Maintenance

Portions of the project which involve complex operation or maintenance requirements shall be identified including laboratory requirements for operation, industrial sampling, and self monitoring.

k. Cost Estimates

Cost estimates for capital and operation and maintenance (including basis), must be included.

l. Environmental Review

Consideration must be given to minimizing any potential adverse environmental effects of the proposed project. Compliance with planning requirements of federal, provincial, state, and local regulatory agencies must be documented.

11.29 Final Project Selection

The project selected from the alternatives considered under Paragraph 11.28 shall be set forth in the final facility plan document to be forwarded to the reviewing authority for review and approval, including the financing considerations and recommendations for implementation of the plan.

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CHAPTER 20

ENGINEERING PLANS AND SPECIFICATIONS

20. PLANS AND SUPPORT DOCUMENTS

Submissions to the reviewing authority shall include sealed plans, design criteria, the appropriate construction permit applications, review forms, and permit fee if required.

20.1 General

20.11 Plan Title

All plans for wastewater facilities shall bear a suitable title showing the name of the municipality, sewer district, or institution. They shall show the scale in feet or metric measure, a graphical scale, the north point, date, and the name and signature of the engineer, with the certificate number and imprint of the professional engineering seal. A space should be provided for signature and/or approval stamp of the appropriate reviewing authority.

20.12 Plan Format

The plans shall be clear and legible (suitable for microfilming). They shall be drawn to a scale which will permit all necessary information to be plainly shown. Generally, the size of the plans should not be larger than 30 inches x 42 inches (760 mm x 1070 mm). Datum used should be indicated. Locations and logs of test borings, when required, shall be shown on the plans. Blueprints shall not be submitted.

20.13 Plan Contents

Detail plans shall consist of: plan views, elevations, sections, and supplementary views which, together with the specifications and general layouts, provide the working information for the contract and construction of the facilities. They shall also include: dimensions and relative elevations of structures, the location and outline form of equipment, location and size of piping, water levels, and ground elevations.

20.14 Design Criteria

Design criteria shall be included with all plans and specifications and a hydraulic profile shall be included for all wastewater treatment facilities. For sewer and lift station projects, information shall be submitted to verify adequate downstream sewer, pump station and treatment plant capacity.

20.15 Operation During Construction

Project construction documents shall specify the procedure for operation during construction that complies with the plan required by Paragraph 11.28(i), Treatment During Construction.

20.2 Plans of Sewers

20.21 General Plan

A plan of proposed and existing sewers shall be submitted for projects involving new sewer systems and substantial additions to existing systems. This plan shall show the following:

20.211 Geographical Features

a. Topography and elevations - Existing or proposed streets and all streams or water surfaces shall be clearly shown. Contour lines at suitable intervals should be included.

b. Streams - The direction of flow in all streams, and high and low water elevations of all water surfaces at sewer outlets and overflows shall be shown.

c. Boundaries - The boundary lines of the municipality or the sewer district, and the area to be sewered, shall be shown.

20.212 Sewers

The plan shall show the location, size, and direction of flow of relevant existing and proposed sanitary and combined sewers draining to the treatment facility concerned.

20.22 Detail Plans

Detail plans shall be submitted. Profiles should have a horizontal scale of not more than 100 feet to the inch (1200:1) and a vertical scale of not more than 10 feet to the inch (120:1). Plan views should be drawn to a corresponding horizontal scale and must be shown on the same sheet. Plans and profiles shall show:

a. Location of streets and sewers;

b. Line of ground surface; size, material, and type of pipe; length between manholes; invert and surface elevation at each manhole; and grade of sewer between each two adjacent manholes (all manholes shall be numbered on the profile);

Where there is any question of the sewer being sufficiently deep to serve any residence, the elevation and location of the basement floor shall be plotted on the profile of the sewer which is to serve the house in question. The engineer shall state that all sewers are sufficiently deep to serve adjacent basements except where otherwise noted on the plans;

c. Locations of all special features such as inverted siphons, concrete encasements, elevated sewers, etc.;

d. All known existing structures and utilities, both above and below ground, which might interfere with the proposed construction or require isolation setback, particular