This treatment plant is situated at Fenwick which is 5 miles north of Kilmarnock, Ayrshire, Scotland. I have operated this plant as a relief attendant from June 1977 - Feb 1980.

Raw water feeding Amlaird Treatment Plant is collected at Raith reservoir, this is an impounding reservoir situated 4 miles north of the plant and has a natural catchment area covering approximately 50 acres.

Due to the catchment source being mainly composed of a peaty surface soil this amounts to a high colour and produces a low Ph somewhere in the region of 4.5.

Hydrated lime is added before clarification to increase the Ph level between 6.0 - 6.5 for optimum floc formation.

There are two types of clarifiers at Amlaird, originally a Horizontal clarifier was used preceded by a flocculation chamber including a slowly rotating paddle. Due to high flow demands an extra clarifier was required and this had to be compact and handle extra demand, after much tender propositions were considered the accepted design chosen was a new concept in clarification called the Simptifier.

This design was loosely based on a circular upflow clarifier comprising a conical shaped bottom with rake arms, the only difference being that fine silica sand was mixed with the incoming water to aid in rapid settlement of floc and thus prevent breakup of the blanket when higher flows were introduced.

The sand was reused and pumped back to the inlet chamber with carrying water and topped up when necessary.

To date I have never known any other plant adopting this design as it worked pretty well apart from general seal wear on the sand pump.

Six Patterson Candy Rapid Gravity filters were used comprising of sand media to a depth of 1.5 meters. A central channel was shared with the inlet and backwash outlet, this ensures even dispersion of inflow and prevents dead areas during backwashing.

Backwashing was done manually and was assessed when the maximum headloss of 2.5 meters was reached also washing was carried out prematurely due to raw water quality or blanket carryover.

Aluminium Sulphate is used as the primary coagulant and this was supplied in block form but this was changed at a later date and incorporated tanks to receive liquid alum.

Hydrated lime is used as a Ph correction due to the high acidity content of the raw water.

Polyelectrolyte ( LT 24 ) used as a flocculation agent.

Chlorine gas as a disinfectant, this was dosed to the final water at 0.8 - 1.0 mg/l.

Sludge from the clarifiers and backwashes was delivered to one of three sludge settlement lagoons and when full was left to settle and recovery water returned to the inlet channel.

Settled sludge was removed by road tanker and disposed at a local landfill site.

The plant operator was responsible to keep the water quality to set parameters set by the chemist and was based on M.P.V. ( Maximum Permissible Value ) this was set well within the M.A.C. ( maximum Acceptable Concentration ) set by the World Health Organization ( W.H.O. )

Five years ago Amlaird has been totally refurbished and automated at a approximate cost of $30 million ( AUD ) but I have not since been back to see the modifications.