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 BOD 5 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.

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A B S T R A C TMounting pressure to conserve water supplies has stimulated greywater recycling to be reused for non-potable uses such as landscape irrigation. A potential greywater source in Jordan as well as other countries is ablution water generated in mosques from prayers' washing rituals. In this study, ablution greywater treatment with the low cost and easy to operate modified re-circulated vertical flow bioreactor was evaluated in terms of its treatment efficiency in order to supply some of the landscape irrigation needs in Al-Balqa' Applied University. The treatment system adequately removed BOD 5 , chemical oxygen demand, total suspended solids, chloride, and Na by up to 94, 88, 90, 48, and 33%, respectively. Dissolved oxygen was significantly increased by up to 133%. Concentrations of Mg, Ca, and K were also increased by up to 29, 63, and 95%, respectively. Nitrate concentration of the treated ablution greywater (TA) increased but remained less than the maximum allowable limit. Treatment efficiency fluctuated with time and quality of untreated ablution greywater concerning electrical conductivity, total dissolved solids, and SO 4 . Concentrations of these water quality indicators were much less than the maximum allowable limits of the Jordanian guidelines. In addition, according to the WHO guidelines, TA is considered suitable for irrigation of ornamentals, fruit trees, and fodder crops. Removal efficiencies of the treatment system were higher than those of other systems previously operated in Jordan. The modified re-circulated vertical flow bioreactor demonstrates great potential for treating low-quality ablution greywater. The wide application of this treatment system in mosques will achieve economic and ecological benefits.