Achieved vs expected results at WWTP
- The recovered amount of suspended solids from the influent was 36%, which is only half of what we thought to achieve (70%). The installation collects less suspended solids, partly because not all of the influent is filtered. When the incoming flow exceeds the finescreen capacity, the surplus will be bypassed. Another aspect is that about half of the suspended solids have a particle size smaller than 0,35 mm and as a consequence will not be filtered out by the finescreens. Most of the cellulose is bigger than 0,35 mm and is filtered out (69%).
- The reduction in energy consumption at the WWTP is only 3%, where 20% was predicted. This is due to the fact that we recover less suspended solids than expected, Also the finescreen installation itself uses more energy than was foreseen.
- The sludge production decreases with 20%, close to the aim of 22%. This leads to less energy use for dewatering of sludge. There is also a reduction of fuel consumption for sludge transport.
- The over-all effect of using finescreens on WWTP Beemster, is a reduction in CO2 emission of about 360 ton/year. Compared to the total CO2 emission of the WWTP this is 12%, where 10% was predicted.