Water Resources Research Act Program

Details for Project ID 2019GU066B

Improvements to sewage treatment on yap: Hydroponics and composting of waste sludge

Institute: Guam
Year Established: 2019 Start Date: 2019-05-31 End Date: 2020-05-30
Total Federal Funds: $49,989 Total Non-Federal Funds: Not available

Principal Investigators: Joseph Rouse

Abstract: Over the past few years, pilot testing has been conducted to assess the possibilities of employing low-cost, environmentally sustainable upgrades to improve the level of treatment for both the raw sewage and the excess sludge. Enhancement to sewage treatment by incorporation of a biocarrier medium was demonstrated, but this is of limited value to full-scale operation due to the relatively small amount of surface area provided for biofilm attachment by the in situ testing apparatus. The apparatus, though, which is permanent in nature and still functional, could continue to contribute to the system’s performance with some routine upkeep and minor repairs. Composting of the excess municipal sludge, as well, has progressed via pilot testing to construction of a recently completed full-scale facility. Preliminary results have demonstrated that a Class-A composted product suitable for public use (as tested by Yap EPA) is achievable. More training, though, is yet required on both the managerial and technical levels to assure ongoing success. A complete understanding of sewage treatment, and disposal or reuse involves an understanding of both the wastewater and solids components. Wastewater is the carrier by which both dissolved and suspended matter are flushed away from municipal dwellings as “dirty water.†As such, it is the more obvious component, which is readily within the awareness of the general populace. The solids component consists of (i) the material that can be easily removed by sedimentation from the influent stream and (ii) the biomass byproduct of biological activity in the STP, which are dealt with separately from the wastewater stream. Generally, the public has little exposure to, or awareness of, the solids component. In Yap, both have been studied and improved upon as parts of recent research projects. The current STP is at a point where it can proceed in a mediocre fashion gaining only minimal benefits from recent investments, or with some additional efforts emerging with a significantly improved system that could graduate to the status of an exemplary (relatively speaking) resource recovery facility (RRF). The final package of this project will include both near-term items that can be realized in the course of this program cycle (2019-20) and long-term plans dependent on budgetary concerns that will require further attention. The immediate objective of this phase is to enhance the wastewater treatment component by employing a hydroponics process within the existing Imhoff tank. A locally present lily plant (Eichornia crassipers) has already been evaluated as suitable for growth in the wastewater. Further testing will be required to determine the benefit for removal of organic contaminants. Parallel to this, ongoing improvements to composting will be pursued by providing guidance for proper methods of hands-on technical operation and of effective managerial practices. Further venues for communicating the project’s overall benefits to the people and natural environment of Yap will also be developed.