P5.2.1.4 Place an alarm on Supply Chemical supply Install or the chemical supply levels of exhausted. repair alarm Chemical tanks to indicate coagulant, system. supply Elevated turbidity when they are close flocculant exhausted. and colour in Urgent order to running out. and filtered water. chemicals. Maintain records of Start keeping chemical. chemical use to record of provide a guide to Usage rates chemical use. the length of time of coagulant, each chemical flocculant supply is likely to and last. chemical. Maintain a reserve supply adequate to cover the time before resupply. Event: PARTICLES NOT REMOVED cont’d P5.2.1.5 Make sure Delivery No delivery Ensure quality chemicals are records records. of treated Incorrect supplied to the water is safe. chemical In source Elevated turbidity correct storage If not, dump used. water: and colour in tanks. Clearly label treated water. filtered water. turbidity supply tanks; Empty, clean Staff absent ensure operator colour and refill during chemical onsite when pH storage tank. delivery. chemicals alkalinity Introduce delivered. No jar test and/or ensure coagulant records. delivery and/or No dosing control procedure. flocculant based on source Require zeta water quality. supplier to potential ensure that jar test. operator is present when chemicals are delivered. Carry out jar tests several and zeta potential coagulants measurements to and determine the best flocculants. coagulants and Consider flocculants and their optimum doses (beware of every time raw disinfection water by-product characteristics formation) (see change. Guide P4.3). Determine relationships for the most appropriate coagulant and flocculant and means of pH control.
P5.2.1.4 Chemical supply exhausted. Place an alarm on the chemical supply tanks to indicate when they are close to running out. Maintain records of chemical use to provide a guide to the length of time each chemical supply is likely to last. Maintain a reserve supply adequate to cover the time before resupply. Supply levels of coagulant, flocculant and chemical. Usage rates of coagulant, flocculant and chemical. Chemical supply exhausted. Elevated turbidity and colour in filtered water. Install or repair alarm system. Urgent order chemicals. Start keeping record of chemical use. Event: PARTICLES NOT REMOVED cont’d P5.2.1.5 Incorrect chemical used. Make sure chemicals are supplied to the correct storage tanks. Clearly label supply tanks; ensure operator onsite when chemicals delivered. Delivery records In source water: turbidity colour pH alkalinity coagulant and/or flocculant zeta potential jar test. No delivery records. Elevated turbidity and colour in filtered water. Staff absent during chemical delivery. No jar test records. No dosing control based on source water quality. Ensure quality of treated water is safe. If not, dump treated water. Empty, clean and refill storage tank. Introduce and/or ensure delivery procedure. Require supplier to ensure that operator is present when chemicals are delivered. Carry out jar tests and zeta potential measurements to determine the best coagulants and flocculants and their optimum doses every time raw water characteristics change. several coagulants and flocculants. Consider (beware of disinfection by-product formation) (see Guide P4.3). Determine relationships for the most appropriate coagulant and flocculant and means of pH control.
treatment-dissolved-air-flotation-feb14-v2.docx