This paper describes an innovative concept for treatment of municipal wastewater, targeting the improved exploitation of the energy content present in the organic matter of raw sewage. The concept is based on a maximum extraction of organic matter into the sludge via coagulation and micro-sieving (100 µm mesh size) to increase the energy recovery in anaerobic sludge digestion and decrease aeration demand for carbon mineralisation. Pilot trials with real wastewater yield a COD extraction of 70-80% of total COD into the sludge while dosing 15-20 mg/L Al and 5-7 mg/L polymer with stable operation of the microsieve and effluent limits below 2-3 mg/L total phosphorus. Anaerobic digestion of the sludge results in high biogas yields of 600 NL/kg organic dry matter input (oDMin) compared to 430 NL/kg oDMin for mixed sludge from a conventional activated sludge process. The overall energy balance of the new concept for a 100 000 pe treatment plant (including biofilter for post-treatment with full nitrification and denitrification with external carbon source) shows that the new concept is an energy-positive treatment process with comparable effluent quality than conventional processes, even when including energy demand for chemicals production. Estimated operating costs for electricity and chemicals are in the same range for conventional activated sludge processes and the new concept

Different technologies for tertiary wastewater treatment are compared in their environmental impacts with Life Cycle Assessment (LCA). Targeting low phosphorus concentration (50-120 µg/L) and disinfection of WWTP secondary effluent, this LCA compares high-rate sedimentation, microsieve, dual media filtration (all with UV disinfection), and polymer ultrafiltration or ceramic microfiltration membranes for upgrading the large-scale wastewater treatment plant Berlin-Ruhleben. Results show that mean effluent quality of membranes is highest, but at the cost of high electricity and chemicals demand and associated emissions of greenhouse gases (GHG) or other air pollutants. In contrast, gravity-driven treatment processes require less electricity and chemicals, but can reach significant removal of phosphorus. In fact, the latter options will only lead to a minor increase of GHG emissions and energy demand compared to the existing pumping station or UV treatment.

A MBBR before an advanced sedimentation step was operated as new wastewater process scheme for maximum COD extraction. The objective of this biological reactor was to modify the soluble COD ratio in primary wastewater. At high loads, the MBBR is able to consume the soluble COD for bacteria activity with very little oxidation. This process changes the soluble COD into particulate COD which is better separate from the wastewater during the following step with coagulation, flocculation and micro sieve filtration. Goals were 95% removal of suspended solids and 80% of COD extracted through separation. To check these new scheme performances, a pilot plant (0.5 to 3 m³/h) was operated at the Stahnsdorf WWTP in the south of Berlin. First results showed that a HRT of 20-30 min and a load 40-60 g CODf /(m2*d) can be recommended for maximum accumulation and minimum oxidation and that the 80% of COD extraction can be achieved (at low oxygen concentration below 1 mg/L). However the performance difference between the scheme with or without MBBR did not exceed 8 %