130 TYPICAL QUEENSLAND LAGOON 
APPENDIX X. 
COMPARISON OF EFFLUENTS FROM A MECHANICAL FILTER 
AND AN INTERMITTENT PLAIN SAND FILTER, OBTAINED 
DURING PERIOD OF THREE MONTHS. 
Average rate of filtration 
throughout period of test 
per 24 hours. 
Intermittent Sand Filter—2.23 million gallons 
Mechanical filter—104 million gallons per acre 
per acre per 24 hours. 
AVERAGE RESULTS OF ANALYSES THROUGHOUT PERIOD OF TEST. 
| 3, |_Oxygen Consumed. | Colour Units. 
5 5 Be es a 5 
Parts per Million. ae EN eB z gs 5 
a5 ibe Coats ° = = 
2s =| a & o 
=< s | ve] mH 
=< = =) ao 
Machine Filter, Applied | 
Water .. Ne oe 218: | 10:57 0.91 || 2.23 — — 
Effluent .. .. . .. | .123 | 5.76] 0:30)|ee 
Sand Filter, ples Water |-.322 | -— | 2.00 3262 5ieu 4.1 
Effluent .. ' 136 | — | 1.13 | 23084) ees 
COMPARISON OF AVERAGE PER CENTAGE REDUCTION IN 
ORGANIC MATTER EFFECTED BY MACHINE FILTER AND 
INTERMITTENT PLAIN SAND FILTER. 
Ss Oxygen Consumed. _ Colour Units: 
om oh: ie 
ea ¢ = 
> =o | w a 
Per cent. Reduction. g : 2 : 3 3 & 
aie | “ eo] G Oo 
< 5 =) = al 
Mncbwie Plies 56.7 | 45.5 | 57.1 | 40.8) =e 
Sand Filter 57.7 | — | 43.5 | 42.5 | 99.1 | 65.8 
