This research documents two innovative designs of septic tanks used for onsite wastewater treatment. The designs were implemented and tested as part of a research project focused on innovative decentralized wastewater treatment solutions. The modified septic tanks were tested at different hydraulic loading rates for sufficient periods to effectively evaluate their performance. The two systems were designed with successive anaerobic and aerobic chambers and were differentiated between attached and suspended growth. The systems were operated at detention times of 4.3, 3.2, and 2.6 days. High removal of organic load was achieved under all loading criteria in both systems. Effluent BOD₅ concentration at lower and higher loading rates were found to be less than 15 and 25 mg/L, respectively, representing a removal rate of more than 95%. Nitrogen was also removed but at a lower rate. The highest TN removal was achieved (59%) in the attached growth system at the lowest loading rate. Although two logs of E. coli removal (99%) were achieved in all systems, E. coli numbers were high enough to necessitate further tertiary treatment. The modified septic tanks proved to be a cost-effective technology with low energy and O&M requirements.

This paper presents an investigation of the role of climatic variability on interannual groundwater and streamflow variability in the southeast United States. For this purpose, streamflow and associated groundwater levels are analyzed for 20 basins that are minimally affected by reservoirs and groundwater pumping. Using the spatially averaged monthly precipitation time series obtained from the Precipitation-elevation Regressions on Independent Slopes Model (PRISM), this paper identifies the recharge and discharge periods that influence the groundwater levels during the winter [January, February, March (JFM)] and summer [July, August, September (JAS)] seasons. Recharge-discharge dependency analyses indicate that precipitation during the previous 3 months influences the groundwater level in a given month. Streamflow in any given month depends on the groundwater level during the previous 3 months. Principal component analysis (PCA) on the precipitation, temperature, streamflow, and groundwater data i...

Treated wastewater is an important component of the water resource in Jordan. As Samra wastewater treatment plant—the largest treatment plant in Jordan—discharges ~110 MCM per year of secondary treated municipal wastewater to Zarqa River, and eventually to Jordan Valley. This research aims at assessing the impact of treated wastewater reuse on the hydrology and environment in the most vulnerable areas within Amman-Zarqa Basin, specifically from As Samra treatment plant to Jerash Bridge. Historical data is collected, field survey is performed, and chemical and biological analyses are performed at eleven selected locations along the study area. Afterwards, all collected data is managed using suitable tools to address the impact. The findings of this research demonstrate high improvement in biological and microbial parameters along the flow path, yet the salinity is increased downstream. It is found that this increase is due to brackish water intrusion, apparently from sandstone aquifer. Analysis of BOD and COD carried out as part of this research showed effective system recovery with COD reduction from 130 mg/L at the effluent to less than 50 mg/l in the downstream. Moreover, microbial activities are reduced, mainly due to self-purification in the river.

The main objective of this paper is to utilize a multi-criteria analysis (MCA) to evaluate Waste-to-Energy (WTE) technologies and identify constraints when examining the placement of a WTE facility. From this, the focus is best summarized by determining the optimal WTE technology in developed countries and how the process would change if implemented in developing nations. In this study, incineration, gasification, and pyrolysis technologies were reviewed and evaluated. The MCA evaluated the different WTE technologies based on a variety of criteria considering environmental, financial, social, technical, and waste quality and quantity. Different weighted factors were used for the two MCAs and different alternative weighted factor scenarios were produced to perform a sensitivity analysis on the results. Overall, pyrolysis was found to be the preferred option for the developed and the developing nation in all scenarios. For developed countries, the highest difference in the overall index score (7 %) was found in incineration between the baseline and scenario 4. In developing countries, the highest differences in the overall index scores were found in scenario 3 for incineration (9 %) and pyrolysis (10 %). Although pyrolysis had the highest overall capital cost due to it being the newest technology, the environmental, social, associated risk, and waste benefits were seen to be more significant on the findings.