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→Recent Performance Research
==Recent Performance Research==
==Recent Performance Research==
*[https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1747-6593.2011.00254.x (O'Hogain et al. 2012) - Physicochemical and microbiological quality of harvested rainwater from an agricultural installation in Ireland]
*[https://ascelibrary.org/doi/abs/10.1061/(ASCE)EE.1943-7870.0000872 (Reddy et al. 2014) - Evaluation of Biochar as a Potential Filter Media for the Removal of Mixed Contaminants from Urban Storm Water Runoff]
**This research study conducted by the Dublin Institute of Technology was commissioned by the federal government to assess the feasibility of utilizing rainwater to replace treated mains for non-potable uses (bathing, irrigation, etc.) on an agricultural property. Two different rainwater harvesting configurations were developed and the results collected over a 1-year period found that median TSS levels were 3.0 mg/L for configuration 1 and 3.5 mg/L for configuration 2. The only parameter that did not comply with local drinking water regulations were the levels of iron, lead and ammonia collected in the cistern of configuration 1 and just ammonia for configuration 2 (O'Hogain et al. 2012<ref>O'Hogain, S., McCarton, L., McIntyre, N., Pender, J. and Reid, A. 2012. Physicochemical and microbiological quality of harvested rainwater from an agricultural installation in Ireland. Water and Environment Journal, 26(1), pp.1-6.</ref>).
**This research study conducted by the University of Illinois found that biochar (as a potential filter media for substrate/filter media in vegetative green roofs) effectively reduced TSS of the runoff by approximately 86% (influent/effluent = 148 mg/L / 20.75 mg/L) and the phosphate concentration by 47% (influent/effluent = 0.57 mg/L / ~0.30 mg/L) . In addition, the concentrations of other heavy metals were reduced between 17–75% (Reddy et al. 2014<ref>Reddy, K.R., Xie, T. and Dastgheibi, S. 2014. Evaluation of biochar as a potential filter media for the removal of mixed contaminants from urban storm water runoff. Journal of Environmental Engineering, 140(12), p.04014043.</ref>).
[[File:Cost effectiveness RWH.PNG|thumb|600px|Schematic drawing of a RWH system with larger capacity for residential or commercial usage. In this schematic pre-storage filtration is used to prevent excess sedimentation, leaves and detritus from entering the system. A piping network delivers water to the tank and a first flush diverter can be installed to diver the first 1-3 mm away from the storage container and be deposited as overland flow, preserving the quality of water for later use (DeBusk and Hunt, 2014<ref>DeBusk, K. and Hunt, W. 2014. Rainwater harvesting: A comprehensive review of literature. 11-12-W. Water Resources Research Institute of the University of North Carolina.</ref>.]]
[[File:DSL extensive green roof.jpg|thumb|600px|Schematic drawing of a Dual Substrate Layer (DSL) extensive green roof that helps to improve vegetation growth and establishment, stormwater retention and can act as a sink instead of a source of TP by improving substrate content by using charcoal, pumice with perlite and vermiculite for adsorption purposes (Wang, et al. 2017<ref>Wang, X., Tian, Y. and Zhao, X. 2017. The influence of dual-substrate-layer extensive green roofs on rainwater runoff quantity and quality. Science of the total environment, 592, pp.465-476.</ref>).]]
*[https://www.sciencedirect.com/science/article/abs/pii/S0925857414004418 (Malcom, et al. 2014) - Measurements of nutrients and mercury in green roof and gravel roof runoff]
**This study compared the runoff and nutrient load reduction performance of sample green roof and gravel plots and two sets of real gravel and green roofs, located in Norfolk, VA. The green roofs and green roof plots outperformed the gravel roof treatments and gravel roof plots in stormwater runoff volume. Meanwhile, concentrations of total phosphorus in runoff from the green treatments were consistently much higher (1.0 – 3.2 mg/L) than that from gravel roofs (less than 0.2 mg/L), even after accounting for rain amount. For half of the storms with a calculated P load, 10 to 180 times more phosphorus leached from the green roof plots in comparison to the gravel ones. Although this is true, the researchers found that the reduction in runoff volume (99.8%) was enough to compensate for the higher concentration of P from the green roofs and resulted in an overall lower total load. This suggests that fertilized green roofs can be a source of phosphorus, and as a result caution is recommended when considering the application of fertilizer during installation/maintenance of green roof practices, especially in the first few years, even though it can improve and expediate plant growth (Malcom, et al. 2014<ref>Malcolm, E.G., Reese, M.L., Schaus, M.H., Ozmon, I.M. and Tran, L.M. 2014. Measurements of nutrients and mercury in green roof and gravel roof runoff. Ecological Engineering, 73, pp.705-712.)</ref>.
*[https://isiarticles.com/bundles/Article/pre/pdf/151961.pdf (Wang, et al. 2017) - The influence of dual-substrate-layer extensive green roofs on rainwater runoff quantity and quality]
**This study looked at the performance ability of dual-substrate-layer (DSL) "extensive green roofs" to both retain stormwater and reduce pollutant load leaching and compared it to that of a traditional (SSL) single-substrate-layer green roof practice. The DSL green roofs supported better natural vegetation growth, (+90% coverage compared to ~80% coverage for SSL), and possessed better average retention values of the total rainfall for four types of simulated rain events. Meanwhile, all of the DSL green roofs appeared to be sinks for organics, heavy metals and all forms of nitrogen but acted as sources of phosphorus loading during heavy simulated rain events. Future consideration was given to adding a mixture of activated charcoal and/or pumice with perlite and vermiculite as an adsorption substrate to help improve TP leaching control in DSLs (Wang, et al. 2017<ref>Wang, X., Tian, Y. and Zhao, X. 2017. The influence of dual-substrate-layer extensive green roofs on rainwater runoff quantity and quality. Science of the total environment, 592, pp.465-476.</ref>).
==References==
==References==