‘SolarMix’ - Innovation in Drying Technology
Nathan S. and Clarke B.
1. CabWater Caboolture Shire Council; 2. Arkwood Organic Recycling Pty Ltd; 3. Mixwell Specialized Transport Pty Ltd
The dramatic population increase in South East Queensland has seen a significant increase in the load placed upon our Sewage Treatment Plants (STPs) and a dramatic increase in the amount of biosolids produced at these STPs. Dewatered biosolids produced by most Water Authorities consists of 85 % water and only 15% solids and it is difficult to achieve a higher solids content with conventional equipment without sacrificing machine efficiency. At present Water Authorities in South East Queensland spend between $40 and $50 per wet tonne for removal and disposal of biosolids which generally represents the highest expenditure component of the total operational budget of an STP. Achieving a significantly higher solid content in the biosolids would obviously represent a major operational cost saving for the Water Authority. A secondary problem faced by these STPs is difficulty consistently meeting Stabilisation Grade B as the biosolids produced have not received the required digestion/treatment times to reach the Stabilisation Grade B requirements. As a result, Stabilisation Grade C biosolids is produced and is always a management problem to both biosolids producers and beneficial reuse end-users in high population growth areas. A simple, economical, and environmentally friendly method of volume/mass reduction and further biosolids stabilisation is air-drying, however, traditional air drying has a reputation for being labour intensive, sometimes odorous, and particularly susceptible to rainfall in coastal areas.
Solar Drying of Sewage Sludge
An Old Method with Modern Technology Using Wendewolf®
Arab Water World (AWW) Magazine 11-12 2004; Water Middle East 2004, Bahrain
Any Sewage Water Work throughout the world will produce sludge, a form of biomass growing in the basins. This biomass has to be evacuated and is, generally speaking difficult to handle! When liquid it has a dry matter of 3 to 4 %, or only 30 to 40 kg per ton of sludge, when mechanically dehydrated to 20 - 25 % most of it is still water, as an average 750 to 800 kg per ton of filter cake.
This remaining water can only be extracted with thermal methods - the sun is our option!
Solare Klärschlammtrocknung in der Praxis
Erfahrungen auf der Kläranlage Glarnerland
Hans-Rudolf Zweifel; Otto Fischli; Herbert Brauchli; Patrik Herrmann
gwa 7/2001 des Schweizerischen Vereins des Gas- und Wasserfaches, Zürich
The water purification plant Glarnerland produces yearly roughly 4 000 tons of digested sludge (DM 25 %).
Through drying, partially using in agriculture and the rest burning in the county's waste incineration plant the final disposal of the sludge is solved. The new solar sludge drying plant uses solar energy and waste heat taken from the electrothermal power station. In the new solar drying plant the digested sludge is partially predried in two greenhouses from a dry mass content of 25 % to 40-50 %. After only one year in operation, it was shown that in the solar plant not only 1 600 tons of water were evaporated, but also that the purification plant's waste heat recovery was efficient. The amount of transports by road was reduced by 40 % and a large overall reduction in disposal costs was achieved.
Introduction of Solar Drying Technology to Trinidad and Tobago
Sunny Mangat; Matt McTaggart; Jim Marx; Simon Baker; Ulrich Luboschik
Weftec Proceedings Orlando 2009
A review of the existing solid managment practices in Trinidad and Tobago and experience elsewhere defined the future needs and identified solar drying of sludge as a preferred technology for the project.
Solar Sludge Drying, Solids, Evaporation, Stabilization, Greenhouse, Vector Control