AFM in Aquaculture

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Large seawater lagoons and lido systems now possible with the minimum of filtration when ACO, NoPhos and APF products are used to treat the water. Perfotmance factor of public swimming pool systems reduced to less than 2 giving an 80% to 90% reduction in chlorine consumption.

AFM in Tertiary Sewerage Treatment for activated sludge aeration systems click here for wireless oxygen monitors click here

Industrial water treatment click here Schematic of system click here	Pressure Filters for AFM	Case studies click here Client list click here	Skid mounted system click here	Reports click here
Results from an independent trial conducted in Spain showing that AFM out-performed all other forms and types for the tertiary treatment of sewage effluent while running at the highest water flowrate.

Tertiary treatment of sewage effluent, the performance of AFM against different systems
TYPE OF FILTER	SS. (mg/l)		Performance %	Turbidity(ftu)		Performance %	C. fecal		Performance %	Velocity
TYPE OF FILTER	inlet	outlet	Performance %	inlet	outlet	Performance %	inlet	outlet	Performance %	m3/m2/h


OPEN SAND FILTER	7.14	2.2	69.24	3.5	2.23	36.3	23120.0	12300.0	46.8	1.2

CLOSED SAND FILTER PRESSURE	8.18	3.82	53.3	5.87	4.76	18.85	22311	18023	19.22	4.96

SAND FILTER WITH CONTINUOUS BACKWASH	7.08	3.82	46.01	2.13	1.79	16.15	14067	10307	26.73	5.4

FILTER CLOTH	14.66	7.33	50	7.16	3.88	45.81	56712	38460	32.18	3.23

FILTER DISCS	5.6	3.1	44.64	2.22	2.06	7.2	30450	21138	30.58	2.12

RING FILTER	7.41	3.98	46.32	3.01	3.17		9447	7761	17.85	2.5

AFM	10.60	0.89	91.60	2.98	0.24	92.00	23000.00	10000.00	57.00	3.59


NOTE : The results in this presentation corresponds to an article published in the Spanish magazine " Tecnolog�a del Agua" in December 2009, page 47. The AFM results correspond to a test made at a sewage by and independent water company in a working effluent plant near Valencia the 11/12/2009

Under normal operating conditions if sand is used for the treatment of sewerage effluent, the sand will rapidly become colonised and blocked by bacteria. However the micro structure, catalytic activity and high negative zeta potential of AFM make it self sterilisation. AFM will not biofoul of coagulate, so it is the perfect media to use in standard pressure filters or rapid gravity for the treatment of sewerage effluent. A simple pressure sand filter with AFM will out-perform a moving bed filter of any deep bed sand filter by a factor of 2 or 3 times, and it is 1/10th of the cost.

The performance achieved is almost as good if not better than membrane systems. AFM will remove solids from the water down to approximately 5 microns. AFM will also remove even smaller particles and adsorb organic molecules by surface adsorption. When used in combination with our resonating ZPMr unit for mechanical coagulation the performance is even better. In addition, membranes result in the development of high concentrations of phosphates, which can cause major problems. NoPhos can be used as a flocculent before AFM to improve efficiency and remove phosphates.

Operational criteria

The loading on AFM for tertiary treatment of sewage is very high as such water flow rate of no more than 5 cubm/hr per square meter of filter bed surface area. Back-flush frequency normally ranges from 3 to 6 hours, back-flush flowrate is 50 cubic metres per hour per square meter of filter bed surface area for 2 to 5 minutes. The back-flush water is directed back to the beginning of the works. Air purging of the bed prior to back-flushing will reduce the amount of back-flush water, air purge rate is 90m/hr

Performance benefits.... typical 90% removal

The graph presents the results from a sewage works showing the suspended solids level in the discharge from the percolating filters. The water then enters the humus tanks, and the water quality results for the works discharge from the humus tanks is presented. The AFM filter receives its water directly from the percolating filters ( AFM influent) but before the humus tanks. The AFM effluent data gives an average value of approximately 7mg/l from an influent of around 70mg/l. 90% solids removal efficiency is achieved.