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Fenton is one of the advanced oxidation processes that can oxide organic compounds efficiently increasing the dewaterability of sludge. This study reports the optimisation of two reagents, Fe2+ and...

Several automatic strategies for aeration control have been investigated so far to favor a significant decrement of energy consumptions in biological processes in wastewater treatment plants (WWTPs). Above all, the intermittent aeration process has demonstrated to have several advantages. This work reports the results of a case study made in a small municipal WWTP where an intermittent aeration control strategy based on the online measurement of real-time nitrogen forms has been implemented to optimize the nitrogen removal and the energy consumption in an activated process. High organic removal efficiency was achieved during the whole experimental period. Results indicated that nitrogen removal efficiency has been improved, especially during winter months, by the control strategy adopted that helped to determine the perfect length for the nitrification and denitrification phases. The intermittent aeration process increased the activity of the biomass, further selecting phosphate-accumulating bacteria and improving the growth of bacteria able to internally store carbon source. Excellent effects were achieved on energy and chemical consumption, with a reduction of about 15% and 23%, respectively. Finally, a 12% reduction of sludge production was also detected.

In the frame of a modern waste management, an important sector concerns the sewage sludge minimization. In recent years a lot of techniques have been developed to reduce the sludge production such as biological, thermal, thermochemical, high-temperature oxidation and mechanical treatments, ultrasonication and ozonation, or using chemical compounds. Among those, the use of an anaerobic side-stream reactor (ASSR) in the conventional activated sludge line is a challenging biological technology able to minimize sludge production in wastewater treatment plants. The ASSR can be easily realized in both new and existing plants as it consists of an ASSR for sludge treatment and reduction where a portion or, in some cases, all the return sludge of the activated sludge process is subjected to alternating aerobic, anoxic, and anaerobic conditions. Studies show that, combining a conventional activated process with an ASSR, sludge yield could be reduced by up to 40–60% without any negative effects, neither on t...