One of the big water authorities in England had tested the WAP/SL for 6 months. The experienced results were deciding for the following framework agreement.
The quality requirements for washed screenings are very high in England, demanding very good washout degrees and dry substance contents (DS). Both sizes together give a quality factor (QF) which explains the biological oxygen demand (BOD5) per g DS. A small QF stands for effective screenings washing (low BOD5) and high DS content. The QF required in England is < 20 mg BOD5 / g DS! But operational reliability and easy maintenance are just as important since many sewage treatment plants in England are operated from telecontrol stations.
The six months testing phase has impressively shown the innovative benefits of the WAP/SL.
A) The very low QF in the washed screenings proves how intensive washing and pressing is by the WAP/SL. The QF reduction of > 95% related to screenings underlines that on the one hand plenty of carbon was washed back into the sewage treatment plant and on the other hand much less screenings had to be removed due to the increased DS.
B) No great difficulties occurred during the full test period and no considerable wear was noticed despite continuous operation of the plant (24 h/d).