scientific analysis of the effluent flowing into the works had been carried out since the first laboratory was built, and effort had also been expended on trying to improve the treatment process. gilbert fowler, who had been the consulting chemist since 1904, went to america in 1912 where h w clarke of the massachusetts board of health was conducting experiments on the oxidation of aerated waste water by micro organisms. the organisms were largely algae, but other organisms thrived in the algal slime. the experiments were on a small scale, using bottles, which were emptied daily and refilled with waste water, allowing the algae to remain on the walls of the bottles.