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The thermal hydrolysis process (THP) is a sludge treatment technique which affects anaerobic biodegradability, viscosity and dewaterability of waste activated sludge (WAS). In 2011 a THP-pilot plant was operated, connected to laboratory-scale digesters, at the water board Regge en Dinkel and in cooperation with Cambi A.S. and MWH Global. Thermal hydrolysis of WAS resulted in a 62% greater volatile solids (VS) reduction compared to non-hydrolysed sludge. Furthermore, the pilot digesters could be operated at a 2.3 times higher solids loading rate compared to conventional sludge digesters. By application of thermal sludge hydrolysis, the overall efficiency of the sludge treatment process can be improved.

Urine separation has great interest from different water boards in the Netherlands. Separate treatment of urine will lead to lower nitrogen emissions from wwtp's with substantial energy savings. Furthermore, it is possible to recover phosphates and remove medicine residues and hormones from urine. In this project, urine collected with urinals and urine-separation toilets, was nitrified in a CSTR. An average ammonium conversion to nitrate of 97% was achieved. The nitrate rich urine was pumped into a small pressure sewer to prevent sulphate reduction. H2S in the gas phase of the sewer system was reduced significantly. From the required amount of nitrate (for >95% H2S reduction) the feasibility of urine nitrification for H2S control was determined. The costs of the concept mainly depend on transport and addition of sodium hydroxide. If urine can be collected undiluted (minimal 3 g N/l) and can be stored in big storage tanks (minimal 10 m3), nitrification of urine can be an alternative for Nutriox addition to pressure sewers.

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Effect van behandeling met oestrogeen en de combinatie van oestrogeen met progestageen op urine-incontinentie