Complex sentence: The CAWST Version 10 biosand filter takes this into account as the volume of the water reservoir is equal to the pore space volume of the sand layer, with a maximum loading rate decreased by 33% to ensure stagnant water in constant contact with granular material.
Split into simpler sentences: The CAWST Version 10 biosand filter takes this into account; the volume of the water reservoir is equal to the pore space volume of the sand layer. The maximum loading rate was decreased by 33% to ensure stagnant water is in constant contact with granular material.