Abstract:
For ages mankind has been producing waste. In prehistoric days this waste was mainly recycled and used for e.g. tools, clothes or fertilizer for crops. But with the prosperity of humanity waste quantities grew. This led to the disposal of waste. At first waste was disposed directly into the environment. Later at restricted areas like landfills, due to increased knowledge of the influence of waste on the health of the ecosystem (introducing water-, soil- and air pollution). Technologies like incineration and composting were introduced to reduce waste disposal and environmental impact. Further reduction of waste streams was obtained trough separation and recycling. Nevertheless, expensive and complex technologies are still required to minimize emissions to air and water, making waste handling a cost intensive business.
In this article, it will be demonstrated that integrating technologies for handling organic waste, waste water and off gasses like biogas, can reinforce performance. And consequently result in a net output of useful products like fertilizer, clean water and energy. Through closure of the waste energy cycle, bio-solids handling might become an energy and cost profitable business. In addition a lower environment impact will be obtained.
For each technology needed to generate and treat biogas, waste water, bio solids, green gas and drinking water, the waste to energy cycle is demonstrated with full-scale installations, based on “proven technologies”.
Keywords
Landfill, Leachate, MBR, Ultra filtration, Nano filtration, Biogas upgrading, Biological desulfurization.
Introduction
Since ancient history, mankind produces waste. As living communities grew, the disposal of waste was increasingly forming problems. Initially just for the human population itself, e.g. odour nuisance, health problems and spreading of diseases. Later, also for the earth’s ecosystem, by destroying the ozone layer and causing the green-house effect. Although waste treatment is considered as a time and money consuming nuisance, it will be necessary to prevent such problems. However, nowadays waste can be seen as useful raw material from which energy or other products can be made, like fertilizers and clean water.
By optimizing the design of waste water plants, landfills and garbage waste disposal plants, it might become possible to make self-sustaining waste treatment facilities. Moreover, combining certain process streams and equipment could result in a net production of energy and clean water.
Within this article such optimisation is demonstrated by using a typical landfill site as example of waste handling. For this landfill the main flows in waste, water, gas and energy are described to present a technical case study. It has to be noted that similar optimisation processes can also be performed at other sites, as long as they have sufficient quantities of organic waste.
