Suspended Solids

The grease trap has the highest amount of suspended solids because of big molecules such as hair and food, small molecules such as dirty foams from hand soap, and even smaller molecules such as oil.

The amount of suspended solids are low at other sites because the grease trap has successfully trapped the molecules from being passed on to the rest of the system.

Turbidity vs Suspended Solids

Turbidity is the lack of clarity in the sampled water caused by suspended insoluble particles interfering with light passing through. Despite a direct link with these two parameters, no co-relation exists between the results for turbidity and suspended solids. The values of both parameters are negligible as all are too low to demonstrate a clear co-relation.

Laboratory Testing

· COD
1) The sample is refluxed with known amounts of potassium dichromate and sulphuric acid.
2) The excess dichromate is measured by spectrophotometry, as the amount of organic matter is proportional to the potassium dichromate consumed.

· Phosphate
1) Ammonium molybdate is combined with the sample containing phosphate ion and form a yellow colour solution
2) A reducing agent, ascorbic acid is added to produce a blue colour solution that is proportional the amount of phosphate present.

· Hardness
1) EDTA, a tritrating agent is added into the sample.
2) Hardness is present if the dye turns reddish-pink from blue colour.

· Suspended Solids
1) Weigh the filter paper with the ceramic dish.
2) Filter paper is placed on the filtration unit and a sample vessel is attached to filter assembly.
3) The filter paper is left to dry in the over at ±105®C for an hour in the oven
4) Then it is being measured again for the amount of solids on the filter paper

· Chloride
1) An indicator, potassium chromate is added into the sample
2) Silver nitrate is used as a titrant in the process of titration.
3) The titred value is noted when the solution turns reddish-brown and calculated by the formula.