Water Resources Research Act Program

Principal Investigators: Joe Rouse, Hyun-Jong Hahm

Abstract: On Yap Island in the Federated States of Micronesia (FSM) the centralized sewage treatment plant (STP) services over 300 connections. The existing STP is an Imhoff tank system, which by design provides little more than removal of easily settleable solid material. The organic material (sludge) that is collected is held in an underlying tank where some degree of digestion occurs. On a quarterly basis, the partially degraded sludge is drawn and placed on a sand-drying bed, from which it is to be air dried and then deposited in the local solid-waste landfill. However, before it can be transported, local farmers take the material for use as a soil conditioner or fertilizer for production of food crops. Currently, regulations in Yap concerning treatment requirements for sewage sludge prior to use are only in draft form. In keeping with U.S. EPA and other international standards, though, there are treatment procedures that can be followed to render the waste sludge suitable for public use. Composting is one such option that can be considered as an environmentally friendly method to recycle the nutrients and organic matter found in the waste sludge. With proper instructions and a limited amount of effort, the local community would soon develop an awareness of how this waste product could be used in a safe manner as a valuable resource. In FY 2015-2016, pilot testing was conducted at the STP in Yap to demonstrate composting techniques suitable for the waste sludge following one week of air drying and mixing with green waste from grass cuttings on the plant grounds (WERI Technical Report 161). From those results, it is clear that one of the unused drying beds could easily be converted and put to use as a compost row with minimal in-house effort. The objective of the proposed project is to construct and implement a composting facility to make use of the waste sludge, rather than sending it to the landfill. This objective will be met by construction of composting bins made of local materials, teaching the proper operating methods, and establishing the protocol for monitoring the quality of the compost produced at the facility. Furthermore, public awareness of the project’s objectives will be promoted by communication with various state government offices (e.g., Resources & Development, Agriculture and Forestry, EPA, etc.) and conducting open public meetings (at schools, NGOs, etc.) at their discretion. Educational factors will include instruction on the dangers of handling inadequately treated sludge-based products and also the potential benefits to be derived from this valuable resource. A technical workshop will be conducted after the end of the project to present the results to stakeholders, including those in other states. In addition, a WERI Technical Report will be produced and made available to all relevant parties.