Chemical Jar Testing


Severn Trent Water Ltd


April '05 onwards

Supplementary chemical dosing can be used to enhance a biological treatment process to meet tight effluent consents (for phosphorus), combining the advantages of biological and chemical treatment options.

The standard method for coagulation jar testing was employed by WatStech Ltd to asses the dose, using a range of chemicals (iron or aluminium), required to chemically remove phosphorus from wastewaters. A number of sample points were employed to determine the optimum dose point of the chemical including crude sewage, settled sewage, mixed liquor samples and final effluent samples. Samples from full scale works were evaluated as well as Biological Nutrient Removal (BNR) pilot plants.

Data collected has been used in Asset Management Plans (AMP), for design purposes and to provide a treatment option for weak wastewaters. Results also provide estimation for chemical usage and costs and allows us to identify the chemical required for optimal results.