per year of disposable nappies. In the late 1980s the site was used to dispose of cow carcasses suspected of having BSE in an unlined pit. By the early 1990s the Environment Agency was authorising the disposal of low-level radioactive waste at the site, including some from the University of Sussex. 4.5 cubic metres were disposed of in 1993. Other hazardous material has included waste from the pharmaceutical and cosmetics industry, tyres and asbestos. A leachate treatment works was built in 1987 comprising two collection lagoons fitted with surface aerators. In 1988 consent was obtained to discharge the aerated leachate into the River Ouse via a ditch on the flood plain, although by 2003 this had not yet been used to discharge any leachate. The accumulated leachate is periodically removed, or used in summer to suppress dust on the landfill. The three unlined pits were used for "dilute and disperse" disposal of waste; accordingly they are continually releasing leachates into the groundwater. The groundwater flows westwards and is assumed to discharge where the chalk meets the alluvial Ouse flood plain. The discharge runs through open drainage ditches and into the Ouse via tidal flaps. These wetlands lie within a conservation area (SNCI) and are close to another at Lewes Brooks (SSSI). In 1997 the water quality at a number of surface water sites on the flood plain of the River Ouse were monitored. It was found that the water at some sites may be contaminated by leachate from the landfill site. The macroinvertebrate communities at these surface water sites may be affected. The leachate from the first two pits is typical of older landfill sites, being neutral in pH, but with high concentrations of NH3-N (260–350 mg/L), Cl (1300–1500 mg/L) and metals including Fe (5–15 mg/L). In 2005 the Environment Agency refused the operator a Pollution Prevention and Control permit for the site (essential for its operation), as leachate from the landfill posed an unacceptable risk to groundwater round the site. Further improvements to the site's liner system were also required. These issues were resolved. The site was profitable for Viridor, the waste-management company operating the site. In 2008–2009 the site contributed £4.4m to its profits. In 2009 the site became full and closed on 16 May. The operator stated that the site will be restored to downland. Gases from the waste are collected and used to generate some 4.9