In recent years there have been significant changes in policy and legislation designed to limit the amount and types of wastes sent to landfill and to encourage an increase in treatment, recycling, reuse or recovery of waste. This is referred to as the waste hierarchy. There is increased customer and public interest in sustainable methods of waste management, and this has encouraged companies like Augean to take an innovative approach.
Augean seeks to continuously improve the services it provides by introducing new processes so they can continue to deliver the best environmental techniques and solutions for waste management. The company explores ways of improving existing techniques and ways in which it can increase the recycling and reuse of materials following treatment and to substitute wastes for products in processes saving material resources.
The waste treatment and recovery facility uses treatment technologies which includes physico-chemical treatment and bioremediation applying the best available techniques.
Before wastes are accepted at ENRMF for treatment a pre-acceptance assessment is carried out by sampling the materials and analysing their composition. This procedure establishes whether it is technically possible to treat the material, and to establish the most effective form of treatment for that waste stream. Materials which if after treatment will not meet acceptance criteria for re-use or disposal in a landfill will not be accepted at the waste treatment and recovery facility.
Soil is washed with water (sometimes with additives) to remove contaminants and recover sand, gravel and soil forming materials. The soil washing plant removes heavy metals from contaminated soils, silts and sludges through a physico-chemical treatment process. Bulk soils are separated into coarse aggregates, sand and silt size fractions and then washed to remove surface contamination. 80 per cent of the output is clean aggregate or sand suitable for reuse. The contaminants present are concentrated into a smaller volume of material which is landfilled directly or following further treatment.
Stabilisation including immobilisation and neutralisation
The purpose of stabilisation is to fix mobile contaminants within the structure of the waste to reduce their polluting potential. The purpose of immobilisation is primarily to change the physical characteristics of the waste but the process can also encapsulate contaminants in the waste. The purpose of neutralisation is to moderate the pH of waste, usually to a neutral condition. Where the pH is a significant factor in the hazardousness of the waste it can be possible to generate a non-hazardous waste output. The outputs of all three processes commonly are managed by disposal in landfill but where the chemical nature of the material being treated and the treated outputs are suitable, the treated material can be recovered for a variety of uses.
Soil is composted to remove organic contaminants and recover the soil. In a controlled environment, specific bacteria can be added to soils contaminated with organic compounds (hydrocarbons) to enhance the process. The degradation of petroleum type materials is promoted through the circulation of air and by controlling levels of moisture.
- The waste treatment centre can tackle a broad range of contaminants.
- Bioremediation provides the potential for recovery and reuse of 100 per cent of the soil.
- Soil washing provides the potential for recovery and reuse of 80 per cent of the input.
- Soil treatment is made available for the treatment of soils where on site treatment is not a viable option, thereby promoting the clean-up of contaminated land.
- Waste treatment is used as a pre- treatment to reduce contamination to acceptable levels and reduce polluting potential before landfilling.
- The use of clean water in the immobilisation processes is minimised by using landfill leachate from the site and collected site surface water runoff. This conserves fresh water resources and immobilises contaminants in the landfill leachate as they are fixed in a solid matrix and returned to the landfill.
- The treatment of wastes for recovery and reuse reduces the need for landfill of wastes.