the incoming sewage ran through a catch pit, which removed large debris, and into the precipitation tanks. liquid was removed from the top, and sludge from the bottom. the sludge was mixed with lime in three sludge pits, and then pressed into cakes. initially, the works produced around 738 tons of pressed cake per week. some 50 tons a day were sold as fertiliser, with the rest being carried by the railway to the old river bed for dumping. the liquid flowed along an open channel to of land, which was used for land filtration, before the treated effluent was discharged into the ship canal. the process was inadequate for the volumes entering the works, and the canal became increasingly polluted. consideration was given to discharging the effluent into the tidal river mersey, by construction of a culvert to randall's sluices, near warrington, or treating it by the use of septic tanks and double-contact bacteria beds. the second option was chosen, as the first would have reduced the flow in the ship canal.