Alan Newman

Much of the solid municipal waste generated by society is sent to landfill, where biodegrading processes result in the release of methane, a major contributor to climate change. This work examined the possibility of installing a type of biofilter within paved areas of the landfill site,
making use of modified pervious paving both to allow the escape of ground gas and avoid contamination of groundwater, using specially designed test models with provision for gas sampling in various chambers. It proposes the incorporation of an active layer within a void
forming box with a view to making dual use of the pervious pavement to provide both a drainage feature and a ground gas vent, whilst providing an active layer for the oxidation of methane by bacterial action. The methane removal was observed to have been effected by microbial oxidation and as such offers great promise as a method of methane removal to allow for development of landfills.

French drains or infiltrating filter drains are commonly fitted with slotted plastic pipe to act as an overflow mechanism when rainfall is too great to allow complete infiltration . The release of the effluent from such pipes is commonly to surface water courses. Whilst there is expected to be some slight degree of protection against hydrocarbon release because of interaction with the drain’s stone infill material this will be severely limited. This paper reports an experiment in which model filter drains with or without geotextile sleeves around the slotted drain are challenged with lubricating oil. The textile was a surface-treated non-woven geotextile manufactured from polyester. The models were challenged with very high loadings of oil, as would be anticipated in a motor vehicle collision occurring close to the drain. A series of simulated 10-20mm rain events over 1 hour were applied and two sample types were collected which either included or excluded any free product. Additional aliquots of oil were added at each rain event. The un-sleeved models were found to release visible free product with the addition of as little as 100ml of oil per linear meter of drain. For the models with geotextile sleeves there was no such release with as much as 2000ml per linear metre. Analysis showed that under these conditions the geotextile sleeved pipes continued to produce effluent with hydrocarbon concentrations well below the 5000μg/l limit usually accepted in the UK 

Co Authors: A.P Newman & F.U Mbanaso

Pervious pavements have been used as water harvesting systems and studies have shown the value of water derived from pervious pavements as irrigation water for landscaping. An alternative system is a modification known as a macro-pervious pavement system. These devices infiltrate water through discrete points into a porous subbase offering all the benefits of the pervious pavement along with an ability to use the specially designed infiltration systems as a means of protecting the sub surface environment from major oil spillages. This paper reports ongoing research aimed at assessing the suitability of water derived from both pervious and macro-pervious pavement installations for irrigation use. Results are reported from ongoing field studies of a 6 year old macro-pervious pavement and, for comparative purposes, a 10 year old pervious pavement system which illustrates the great potential of pavement derived water from both types of system and some of the problems which require care in the management of the irrigation system.

co authors: A.P Newman; Mbanaso, F.U

"Permeable pavement systems are important part of the sustainable urban drainage system (SUDS). Over a decade ago, it was proposed that the pervious pavement system (PPS) has the capability to store water for reuse, the possibility of using the SUDS device simultaneously in source control and water recycling applications have not been holistically investigated by previous studies. This paper reports experiments where water from geotextile incorporated permeable pavement system models on which 24 mL/m2 of hydrocarbon was applied as a pollutant. A single dose of 17 g of nitrogen, phosphorus and potassium slow release nutrients (applied to encourage biodegradation) was administered to the surface. The PPS recycled water was used to irrigate tomato plants (Lycopersicon esculentum (fantasio hybrid)) and rye grass (Lolium perenne) for ten weeks. The growth, development and heavy metal content of the organs of these plants were compared to that of plants from untreated rigs and with plants treated with de-ionized water (DI) as well as the pH, sodium adsorption ratio and electrical conductivity. The comparative performance of the plants indicated that the water from the treated rigs supported plant growth more than the water from the untreated test rigs and DI. Heavy metal analysis of the plants organs indicated that the metals were at normal levels and below toxicity levels for plants and livestock. Soil structure tests showed that there were no salinity or soil structure issues. Heavy metal analysis of soil also indicated that the metals were within normal range and below toxicity levels. These results further demonstrate the water recycling capability of the PPS and its potential use for irrigation purposes.
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Most available water resources in the world are used for agricultural irrigation. Whilst this level of water use is expected to increase due to rising world population and land use, available water resources are expected to become limited due to climate change and uneven rainfall distribution. Recycled stormwater has the potential to be used as an alternative source of irrigation water and part of sustainable water management strategy. This paper reports on a study to investigate whether a sustainable urban drainage system (SUDS) technique, known as the pervious pavements system (PPS) has the capability to recycle water that meets irrigation water quality standard. Furthermore, the experiment provided information on the impact of hydrocarbon (which was applied to simulate oil dripping from parked vehicles onto PPS), leaching of nutrients from different layers of the PPS and effects of nutrients (applied to enhance bioremediation) on the stormwater recycling efficiency of the PPS. A weekly dose of 6.23 × 10−3 L of lubricating oil and single dose of 17.06 g of polymer coated controlled-release fertilizer granules were applied to the series of 710  mm × 360  mm model pervious pavement structure except the controls. Rainfall intensity of 7.4 mm/h was applied to the test models at the rate of 3 events per week. Analysis of the recycled water showed that PPS has the capability to recycle stormwater to a quality that meets the chemical standards for use in agricultural irrigation irrespective of the type of sub-base used. There is a potential benefit of nutrient availability in recycled water for plants, but care should be taken not to dispose of this water in natural water courses as it might result in eutrophication problems.