Redhill EMAS 2006 - Biffa

SITE SCHEMATIC04The schematic diagram illustrates the site operations and typicalenvironmental controls which are in place at Redhill Landfill Site tominimise its impact upon the environment.1 MONITORING BOREHOLESThe site is surrounded by a series of gas andgroundwater boreholes; that go to a maximum depthof 78 metres below ground level; Water QualityMonitoring Samples of groundwater and surfacewater are taken regularly from 18 fixed points andanalysed for a variety of parameters; Landfill GasMonitoring Regular monitoring of 139 samplingpoints (perimeter boreholes) is carried out formethane; carbon dioxide and oxygen;2 BASAL ENGINEERINGThe basal formation is constructed to an agreedprofile using engineered clay and synthetic materials;permanent leak detection systems are in place tomonitor the performance and integrity of the sitelining system;3 LANDFILL GAS CONTROL SYSTEMSA physical barrier comprising a plastic geomembranecoupled with engineered clay liner prevents off-sitemigration of landfill gas;4 CONTROL AND RECEPTION OF WASTEPrior to acceptance; wastes are assessed and receiveapproval references; At the Weighbridge; computerrecords are generated and then the loads aredirected for further inspection prior to final deposit;5 SITE MANAGEMENT OFFICEThe offices are also the South East Regional centrefor Biffa's Landfill activity;6 WHEEL CLEANERRequired to ensure both site and public highway iskept free of mud debris;7 VISUAL INTRUSIONSoil bunds and tree screens are positioned to helplimit the visual impact of the site; Progressive cappingand restoration follows quickly behind landfilloperations;8 POWER GENERATION PLANTOur power generation engines provide electricity tothe local distribution network and our quarrydewatering system and site domestic use;9 LANDFILL GAS FLARESurplus gas is diverted to a ground flare to minimisegreenhouse gas escape and the emission of odours;10 RESTORATIONThe site is being continually restored; a plasticgeomembrane is installed to prevent landfill gasemissions to atmosphere and water infiltration;11 GAS EXTRACTION SYSTEMSLandfill gas is extracted from wells within the wastemass and pumped to the power generation plant orflare;12 LEACHATE CONTROLLeachate levels are monitored and controlled byextraction from wells within the waste mass;13 LEACHATE TREATMENT PLANTThe plant is designed to reduce ammonia levels withinthe Leachate prior to its discharge to the sewernetwork;14 WORKING AREAThe waste is placed and compacted in layers;normally achieving a density of 1 tonne per cubicmetre; each layer is covered to prevent wind blownmaterial and control of pests;15 WASTE DEGRADATION AND STABILISATIONThe deposited waste breaks down over time toproduce landfill gas (a mixture of gases mainlycomprising of methane and carbon dioxide) andLeachate (contaminated water).1213