Susanne Dittke Cape Town December 7, 2006

Dear CBSM Listserve Members

Greetings from South Africa. My name is Susanne and as an environmental consultant I am part of a team who has been given the challenging task to develop a Strategic Road Map for the Johannesburg City Council utiltiy waste service company Pikitup to reduce waste to landfill by 50% within the next six years with the further aim to develop a zero waste to landfill plan by 2010. Pikitup currently serves 100% of all JHB households and small businesses and it has some very large commercial clients as well. From our first waste volume information we find that a considerable part of the waste going to landfill is of organic nature (other than clean garden and parks waste which is already increasingly diverted and composted and will continue to do so in future). The situation of other organic waste streams currently disposed off but in principle recoverable for further treatment appears to be as follows (where no numbers where available we used estimates) and all numbers are calculated annually: Putrecibles combined housholds, business weekly collection : 53 000 tons (we work here on an estimated 70% recoverable portion based on a successfully working dry/wet waste separation) Fines and residues (also ash) from domestic waste sources : 16 000 tons (this number is based on estimated recovery potential of 10%) Dailies - mostly food waste from restaurants, grocers etc collected daily : 34 000 tons (based on a 70% recovery rate) Annual total: 103 000 tons In addition there might be sludge from various water treatment works we could add. There are also a huge amounts of nappies that could be recovered as part of a "dirty" material recovery facility operation but since they are containing plastics I am not sure if those would be suitable for any organic waste treatment at all- generally we estimate this could be around another 25 000 tons. I appreciate any assistance greatly you could give me to find information about feasible technical options for treating mixed organic Muncipal Solid Waste (MSW) (but also advising on how to combine some of those organic waste streams listed above (where possible) and which ones to keep separate for suggested treatment) .

What technology would be suitable and hopefully affordable to treat the organic MSW fraction on a large scale capacity in addition to promoting more small scale onsite anaerobic digestion systems, worm farms and composting facilities ? I did a fair deal of desktop research but found very few technical solutions for treating organic MSW directly and what I found sounded suspiciously like unproven snake oil seller's sales claims (e.g. Alphakat ; Green Power- claiming to be able convert mixed organic MSW into biodiesel). If you can shed some light on what works elsewhere (ideally low tech and high labour intensive) your input or guidance will be of invaluable assistance to me as I really try to avoid expensive mistakes here (this is not my specialist professional area) and I do not want to reinvent the wheel either.

Regards
Susan

Susanne Dittke
Integrated Resource and Waste Management Specialist
EnviroSense CC 61 Peninsula Road
Zeekoevlei 7945
envirosense@xsinet.co.za
www.cleanerproduction.co.za