Various technologies have long been developed in waste management such as incineration and recycling, even the last 30 years there have been rapid developments in the scope and depth of technical processes. This was conveyed by Hans-Joachim Alfeld from Germany's Senior Experten Service in a public lecture entitled "Best Practices of Solid Waste Treatment Technology in Germany and Other Countries" organized by the Department of Mechanical Engineering Education, Faculty of Engineering, Yogyakarta State University (18/02/2020). This agenda is also a collaboration with the Indonesian Biomass and Biogas Association and the Indonesia Solid Waste Forum.

Hans explained that landfills are locations for the deposition of hazardous substances or can no longer be used so they must be permanently removed from circulation. "In this system using the macro encapsulation model, which is a process where hazardous materials in waste are wrapped in a large matrix structure," he explained.

"The encapsulation technique depends on the type of waste and the degree of danger by using a double seal system, which is two different sealing principles for greater safety. If the first seal fails, the second must maintain the sealing function, "he continued.

"In general, seals consist of combination seals with a layer of mineral clay and a covering membrane with a thickness of 2-3 mm. In addition, the bottom must also be waterproof, "he continued.He added that in waste management there is often a mixture of waste so that to recycle waste must be sorted and separated where in addition to general sorting methods, special techniques must also be used.

According to him in Germany in the process of sorting waste starts from collecting in one trash in the sorting location automatically. Initially, filtered in various sizes with various techniques, such as star or drum sieves.

"Often waste is treated before it is used further through a variety of different devices and techniques," he explained.

There are also various special areas with their respective techniques, such as fermentation, composting, electrical waste recycling, neon tube recycling, battery recycling, special waste chemical treatment, paper recycling, plastic recycling and pyrolysis.