As mentioned previously, anaerobic systems are a particularly relevant technology for consideration; the resource requirements, environmental impact and robustness of the anaerobic digestion of effluents and solid residues offer distinct advantages in the Arab region. In this section we consider other factors crucial to these technologies being successfully implemented. In most developing countries, technologies are developed locally. While the public sector typically invests in long-term research capacity that later becomes the foundation of technological innovation, the private sector is increasingly involved in short-term investment in research and development.