Introduction

Our client is the Village of Sipaulovi. Their acting representative is George Mase. He is the Community Services Administrator for Sipaulovi Village. He also serves as the liaison between the Sipaulovi Village Board Directors and our team.

To design a wastewater collection and treatment facility for the village of Sipaulovi, which meets the regulations provided by Indian Health Service. This system must be able to incorporate the existing sewers, and create a central sewer system for the village, which will be easily incorporated into any new development within the village.

3. Existing Wastewater Systems

Sipaulovi Village's current wastewater treatment system consists of three independent lagoon sites. One of the sites, on the lower southeast corner of the village has two lagoons, which run alternately. The school's lagoon is lined. In the picture of the school's lagoon, the large black mounds that can be seen are the liner which has trapped air under it. The third site, called the "Toreva lagoon" serves the residences on the mesa of Sipaulovi.

Pictures of the existing lagoon sites can be viewed by clicking the link below:
Lagoon Pictures

Sipaulovi Village, is located at Second Mesa, on the Hopi Reservation. Below is a site map which shows the location of the village in relation to Flagstaff. The site of the new wastewater treatment system was designed to be located approximately 3 miles away from a proposed housing development, southeast of the village. The treatment site is beside a dirt road off of Highway 87. The proposed site can be seen in relation to the village by clicking the Aerial Photo link. On the Aerial photo, the existing school's lagoon is circled in green, the lagoon on the southeast corner is circled in red and the proposed site of the wastewater treatment system is enclosed in a cyan square. The Toreva lagoon cannot be seen in the aerial photo.

1. Odor issue. There are complaints about the odor released from the lagoons into residential areas. Future development will surround the existing lagoons. The site picked by our client is away from residences and commercial areas. The prevailing wind in the area will take odors away from the village.
2. Capacity. The population of the village of Sipaulovi will increase by 50% within the next ten years. The existing lagoon for the school will be insufficient within the next five years. There will be commercial development which will contribute wastewater flow to the lagoon on the southeast corner and may exceed its capacity. These concerns will be addressed by designing a centralized wastewater treatment system which will be able to handle the increases in flow for the next twenty years. Area will be set aside for expansion of the facility, but this area will not need to be developed for at least twenty years.
3. Aesthetics. Our client prefers the constructed wetlands approach to water disposal. Wetlands areas are rich in plant life and will attract wildlife. The client expressed that they would prefer sinuous evaporative channels, rather than a large evaporative basin, for aesthetic reasons.
4. Reuse. The client originally requested a design which would allow for re-use of the effluent. Their intent was to use the water for irrigating non-food crops. This alternative was not feasible due to the testing requirements set forth by EPA for water re-use.
5.Cost & Maintenance. The design must be low cost and low maintenance. There is currently no electricity at the site, so the system was designed to run by gravity flow only. Water re-use was not incorporated into the design, to reduce operating cost due to testing of the effluent. The wetland channel design will require occasional draining and weeding.

DCS solutions conducted research and met with Mike Stover from Indian Health Service to determine the best alternative for the wastewater treatment site. The two major designs that were considered were a facultative lagoon (what the village has now), or an Oswald system. Mike Stover recommended the Oswald system because these systems have shown nearly complete reduction of solids, with minor buildup over periods of twenty years. A facultative lagoon would require dredging to remove solids accumulation every few years, but the Oswald would not require this to be done. Mike Stover also recommended that an evaporative basin be constructed in lieu of a wetlands, because the reduced cost of construction would make that design more likely to be funded by I.H.S. However, the client prefers the constructed wetlands method of water disposal and our design will be suited to their request. The increased estimated construction cost will be used by our client as a guideline for what to expect when they actually begin to develop their centralized system.

Calculations and plans for our design can be found on the third page of this site.

The "Next" page describes the progression of the Senior Capstone classes at Northern Arizona University, and lists the deliverables that were turned in for this project.