40W201 Wasco Road, Suite D • St. Charles, IL 60175• Ph: 630.587.0470 • Fax: 630.587.0475







Wastewater Engineering

Trotter and Associates, Inc. provides a complete range of wastewater engineering services including planning, design and construction supervision. The TAI Team is able to look beyond text book answers and develop project specific solutions to meet our client's current and future needs.

TAI's proven track record has earned the firm a exemplary reputation. Our professionals maintain on the cutting edge of technology and current with the latest information on pending regulatory changes through involvement with several local, regional and national professionals as well as continuing education programs.

Some of the wastewater engineering services provided are:


  • Facility Planning Updates
  • Collection System Design & Rehabilitation
  • Infiltration / Inflow Studies
  • Treatment Facility Design & Rehabilitation


Facility Planning



The Facility Planning process is a cooperative effort between engineers and owners to produce realistic forecast for population densities, evaluate existing collection and treatment infrastructure, determine the impact of regulatory changes and assess the community's needs for the future. Planning is a critical element in the development of the wastewater system, as this phase establishes the basis from which all future decisions are made.

Trotter and Associates has developed a comprehensive approach to Facility Planning, which includes:

  1. General Background - comprehensive overview of the communities history, existing infrastructure and purpose of the plan
  2. Community's Needs - detailed assessment of existing population densities and usage broken down by drainage basin
  3. Collection System - an overview of each basins infrastructure capacity and needs as well as recommendations for extension of service
  4. Lift Stations - a detailed analysis of the age, condition and needs assessment for maintenance of this critical infrastructure.
  5. Existing Treatment Facility -a complete audit of the existing infrastructure including age, condition and remaining service life as well as a thorough evaluation of each processes performance, efficiency, biological and hydraulic capacity
  6. Treatment Facility Upgrades - an exhaustive analysis of alternatives to meet the community's long term needs considering the potential for incorporation of innovative technologies, process reliability, ease of operation and lifecycle costs.
  7. Anti-Degradation/ Environmental Impacts - evaluation of alternatives to mitigate the environmental impacts of increased loading from expansion of treatment capacity as well as the positive impacts of nutrient removal or land application
  8. Recommendation and Implementation - decisive recommendations for necessary collection and treatment facility improvements and associated costs; analysis and recommendations for annexation, connection and user fees; recommendation for an implementation plan and schedule.

Infiltration/ Inflow Studies



Infiltration and Inflow Studies, as well as SSES programs, are necessary to accurately predict the impacts of wet weather events on a community's collection system and determine the remaining capacity to support extension of the service to developing areas. Trotter and Associates, Inc. has completed several sanitary sewer evaluation surveys as well as infiltration and inflow studies. The TAI team also has extensive experience with sanitary sewer modeling, GIS data collection, and flow monitoring. Our team of professions work closely with our clients to develop a cost effective program to maximize the communities investment into infrastructure maintenance.

Collection System Design & Rehabilitation



Whether it is the extension of sewer, development of a new interceptor or rehabilitation of the existing collection system, TAI has the expertise, experience and resources to meet our clients goals. TAI is continually reviewing new materials and techniques for improving infrastructure life, reliability and constructability. TAI's survey and drafting technicians are extremely detail oriented and spend the required time to document and accurately describe the existing conditions making TAI's plans clear and concise. This commitment to quality results in lower change orders from contractors and ultimately saves our clients money.

Our team of profesionals have completed countless rehabilitation projects using pipebursting, slip-lining and insitu-lining. TAI has developed a methodology for plan and project documentation preparation that is extremely efficient and cost-effective, which reduces the overall project cost without sacrificing accuracy or quality.

Trotter and Associates, Inc's principals were responsible for the design and implementation of ne of the first, low pressure sewer system installed in northern Illinois. TAI's professionals are well versed in the proper application and implementation of the systems. By understanding the advantages and maintenance issues related to low-pressure systems, TAI is able assist clients with evaluation and implementation of this alternative technology.

The TAI team has completed a series of pump station ranging in size from a few hundred gallons per minute to tens of thousands. Whether it is an existing pump station which is need of rehab, our installation of a completely new structure, Trotter and Associates, Inc. has the expertise and experience to implement a reliable low maintenance pump station for the community.

Wastewater Treatment Design & Rehabilitation



Wastewater treatment is the physical, chemical and biological processes by which pollutants are removed from contaminated water. The pollutants that need to be removed from domestic sewage include fixed solids, microorganisms, nutrients, metals, etc.

While wastewater treatment has been around for approximately one hundred years, the processes involved are continually being improved. As with most industries, improvements are driven by several forces. First, a more in-depth understanding of the degradation of waterways caused by pollutants results in increasingly stringent governmental regulation. In addition, tighter budgetary constraints force facilities to operate more efficiently then ever before. Finally, the increased competition in the private sector forces manufacturers to develop better, more reliable equipment.

The needs for wastewater treatment facility improvements are the result of several forces as well.



· Growth in the Community
· Pending Changes in Regulation
· Aging Infrastructure

Increase in Capacity

As the population continues to increase, so does the demand for adequate wastewater treatment capacity. Wastewater treatment facilities are designed to serve a specific population equivalent. The design of the treatment facility is based on a twenty-year life cycle, however, at present population growth rates, treatment facilities need to be expanded well before the end of the design life.

Constructing additional treatment units is typically the recommended alternative to providing additional capacity. However, it takes a great deal of engineering design to ensure that the new units will function properly in conjunction with the existing units, so that the plant will continue to provide an adequately treated product.

Wastewater treatment facility capacity is directly related to collection systems capacity to carry wastewater from the user to the treatment facility. A large portion of the design of the system is dependent on the topographic characteristics of the area served. There is a certain point at which it is no longer cost effective to treat flows from remote developments and a new treatment plant must be constructed.

A third alternative, which requires increased operator attention, is the optimization of existing treatment units. By installing enhancements such as covers on aeration basins, fixed film media within the basin or baffles in clarifiers, treatment facilities can improve the efficiency of existing treatment units. However, this approach typically requires a trial period before the increased capacity is recognized by regulatory agencies, as the design parameters will not fall within the regulatory guidelines. As a result, this approach is only an option when time is not a concern.

The TAI staff evaluates each particular situation on its own merits as each client's needs and circumstances are unique. From that evaluation, the TAI staff develops the best solution for the client instead of simply copying solutions from the past.

Future Regulations

As the population continues to increase, so does the need to further protect the environment. In order to ensure stability within the environment, governmental agencies on the federal, state and local levels are continuously evaluating the effectiveness of wastewater regulations. In order to continue to protect the environment from the effects of an ever-increasing population, most governmental regulations are becoming more stringent.

Because of this, Trotter and Associates, Inc. has made a commitment to remain abreast of any changes within the industry. By attending organizational meetings, trade shows and regulatory functions, the TAI staff is able to keep the client informed of any pending changes before they become an issue. The TAI staff provides the client with increased flexibility and security -- the client can be assured that the TAI staff is watching out for their best interests.


All components that constitute a treatment facility have a useful life span. Depending on the type of component, this life span can vary from between two and fifty years. As part of an operating budget, treatment facilities include funding for the replacement and/or repair of components that show wear and require attention.

It is vital that all components throughout a treatment facility remain operational. While it is the responsibility of the treatment facility’s staff to ensure that routine maintenance is performed, inevitably equipment will wear out to the point where it will no longer operate properly.

In the increasingly sophisticated industry of wastewater treatment, improved processes and equipment are constantly being introduced. The TAI staff is responsible for informing the client of these new options as well as evaluating simple replacement strategies.