Cost Effective and Efficient Energy Recovery from Biosolids for the Largest Plant in the Kingdom of Jordan

The USAID Water Reuse and Environmental Conservation Project works to protect and conserve Jordan’s scarce water resources; one task in that project is to prepare a biosolids management feasibility study for the As-Samra Wastewater Treatment Plant, which treats more than 60% of the country’s generated wastewater.The first phase of the feasibility study is to assess existing conditions and to screen and evaluate viable biosolids processing options, with the goal of identifying the best ones. Detailed analysis of those identified option(s) was conducted in the second phase. The first phase of the study resulted in four shortlisted options that recover energy from the dried biosolids: incineration, gasification, monofill (biosolids landfill only), and use at local cement kilns. Other options such as land application and composting, while potentially remaining viable for a portion of the biosolids, were not further evaluated in detail since the option is expected to process the entire biosolids amount. The second phase’s detailed evaluation of the shortlisted options included 20 year present worth, ranking based on established evaluation criteria, and financial analysis. The gasification option was eliminated due to its high capital cost for the size of the facility. The shortlisted options require some form or biosolids drying. Taking advantage of the arid condition of Jordan, solar drying beds of dewatered biosolids followed by mechanical windrow drying allowed cost effective drying of the biosolids for further processing as compared to energy extensive thermal drying.The results of the evaluation indicated that all three final options are technically viable and could be carried forward. While incineration and cement kiln options scored the highest overall in the evaluation criteria, the monofill scored a reasonably close third with no notable obstacles in its implementation provided it is operated by the private sector. Financially, the monofill with an energy production option proved to be significantly more viable offering the most attractive life cycle cost and return on investment. Accordingly, it is recommended that the project moves forward with the monofill with an energy production option.