‘Towards a sustainable pit latrine management strategy through LaDePa technology' is the title of the main feature in this section.

South Africa, along with most of the developing world faces significant challenges in the provision of sanitation services in general but in particular to the urban poor. Although South Africa has made significant inroads into the backlog in sanitation by the provision of pit latrines, very little with regard to the management of pit latrines, once they are full, has been done, particularly with regard to their sustainability.

LaDePa (Latrine Dehydration and Pasteurisation) is a machine that provides a containerized method of producing a nutrient-rich soil conditioner that is workable and improves sustainability on a number of fronts, by removing the detritus, pasteurizing and drying the sludge to beyond the sticky phase. Due to its use of low technology, the system relates well to the social environment where pit latrines are usually encountered in the developing world, urban environment, in that it provides both business and work opportunities for the poorly skilled.

The feature article comes from UNEP in Norway and discusses, in an interesting case study of Heftingsdalen, the problem of over-consumption and waste. The area allocated to landfill is filling up much faster than in the gloomiest forecast. The current site has already reached the level originally planned for 2014. At this rate Heftingsdalen will soon be full, the only solution being to spill over into the surrounding forest. The plant could also obtain permission to raise the embankment making room for several tens of thousands more tonnes of waste, but that too is only a short-term solution.

This month, our article comes from India. ‘From seaweed to biofuels' looks at a recent agreement between Novozymes and Sea6 Energy whereby Novozymes, a world leader in bioinnovation, announced an exploratory research agreement with Sea6 Energy, an India-based company, to jointly develop a process for the production of biofuels from seaweed. The research alliance will use enzymes to convert seaweed-based carbohydrates to sugar, which can then be fermented to produce ethanol for fuel, fine chemicals, proteins for food, and fertilizers for plants. Novozymes will research, develop, and manufacture enzymes for the conversion process, while Sea6 Energy contributes its offshore seaweed cultivation technology.

"Seaweed is a natural complement to our efforts to convert other types of biomass to fuel ethanol," commented Per Falholt, Executive Vice President and CSO of Novozymes. "More than half of the dry mass in seaweed is sugar, and the potential is therefore significant."

A look at the next generation of thickener feedwells is the subject of this feature article by Dr A Krassnokutski, of Roymec Technologies, Johannesburg. Metallurgical thickeners have evolved over the past century in large technological leaps rather than through slow and steady progression. The first of these technological leaps was the introduction of polymer flocculants in the 1950s which transformed large diameter conventional thickeners into smaller diameter high rate thickeners The next leap was the development of more efficient feedwells in the 1980s which better mixed the flocculant into the feed and more evenly distributed the feed into the thickener body. Lastly, was the development of so-called 'auto-diluting' systems some 20 years ago.