No abstract

Providing safe and reliable sanitation services to the billions of people currently lacking them will require a multiplicity of approaches. Improving onsite wastewater treatment to standards enabling water reuse would reduce the need to transport waste and fresh water over long distances. Here, we describe a compact, automated system designed to treat the liquid fraction of blackwater for onsite water reuse that combines cross-flow ultrafiltration, activated carbon, and electrochemical oxidation. In laboratory testing, the system consistently produces effluent with 6 ≤ pH ≤ 9, total suspended solids (TSS) < 30 mg L −1 , and chemical oxygen demand (COD) < 150 mg L −1 . These effluent parameters were achieved across a wide range of values for influent TSS (61−820 mg L −1 ) and COD (384−1505 mg L −1 ), demonstrating a robust system for treating wastewater of varying strengths. A preliminary techno-economic analysis (TEA) was conducted to elucidate primary cost drivers and prioritize research and development pathways toward commercial feasibility. The ultrafiltration system is the primary cost driver, contributing to >50% of both the energy and maintenance costs. Several scenario parameters showed an outsized impact on costs relative to technology parameters. Specific technological improvements for future prototype development are discussed.

Curium oxide has been shown to vaporize congruently as Cm,O •. Effusion measurements have been carried out, using tungsten and molybdenum celis, over a temperature range from 1800 to 2600 0 K and a pressure range from 10-9 atm to 0.5 mm. The linear least-squares fit to the total volatility, calculated as Cm20., yields the equation 10gP (atm) = 7.32 (±0.26) -29050 (±590) / T (OK). The corresponding MJ"oo OK and LlS22000K were computed to be 133.0±2.7 kcal/mole of gas and 33.5±1.2 cal/deg·mole of gas, respectively. The predominant vaporization process is thought to be the formation of CmO (g) and 0 (g), based on estimates of the heat of formation of Cm,O. (s), comparison of experimental and estimated entropies of vaporization, consistency between second-and third-law heats of vaporization, and trends in the vaporization behavior of lighter actinide oxides. The heat of vaporization at OaK would then be 429±8 kcal/mole of Cm,O •.