Design, Bidding, and Construction Experiences of Publicly Owned and Operated Onsite Wastewater Systems in Four Communities
USDA Rural Development, Iowa (USDA RD) has funded 4 EPA Model 5 Management type onsite wastewater projects; 2 projects are with existing rural water utilities, 1 project with a city, and 1 project with a county government. All are existing communities with a small user base and low household incomes. The design, bidding, and construction of these types of onsite wastewater projects, while simple for a single homeowner, is compounded 40 fold for a small community project. This paper will discuss the experiences of these 4 projects, provide insight on what we have learned and the design guide developed to use for future community based onsite wastewater projects.
Failing and inadequate onsite wastewater systems affect the environment, surface and ground water, property values, and public health. While sometimes it is difficult to show contamination or pollution effects from individual onsite systems to the environment, there is little doubt that improperly operating systems do affect the quality of the environment around us.
USEPA developed a guide titled “Voluntary National Guidelines for management of Onsite and Clustered (Decentralized) Wastewater Treatment Systems” published March 2003. This guide is referred to as the “Management Guidelines” which promote the development of comprehensive management programs and stressing the importance of establishing performance requirements to protect public health and the environment. A management plan should define the roles and responsibilities of the regulatory agencies, responsible management entity, operator, and users to insure the appropriate system is selected and maintained.
In Iowa, USDA RD began looking at a comprehensive approach for addressing the wastewater needs in rural areas. Small communities, cities with populations fewer than 300, typically do not have the resources or organizational capacity to solve or effectively maintain their wastewater issues. USDA RD realized in the early 1990’s the key to the viability of a wastewater system is a responsible management plan. The goal of the management plan is to outline a sustainable program by which a responsible management entity will own, finance, design, construct, manage, operate, and maintain the wastewater system in small rural communities. These early projects were using central collection and treatment systems as a feasible solution. In the late 1990’s several projects were found not to be financially feasible as central collection and treatment systems and the only feasible options were onsite systems. USDA RD is very supportive of the USEPA initiative an has been seeking out interested parties to be the responsible management entity.
This paper is a review of the design processes utilized in 4 decentralized onsite wastewater projects funded by USDA RD in Iowa. The management entities utilized were existing rural water utilities, a city, and a county government. All projects are in existing communities with a small user base and low household incomes. This paper will discuss the steps in the design and bidding process, provide guidance on what we have learned and a design guide developed to assist in planning future onsite wastewater projects.
The state of Iowa regulated the responsibility of all onsite wastewater systems having less than 1,500 gallons per day design flow to the counties. There are no educational or training requirements for county sanitarians, site evaluators, contractors, or maintenance providers in the regulations. In most counties the county sanitarian performs percolation tests or requires the installation contractor to do the testing. There are few trained site evaluators, designers, installers, and county sanitarians in Iowa.