Transactions of the American Society of Civil Engineers, vol. LXXII, June, 1911 / Water Purification Plant, Washington, D. C. Results of Operation. - American Society of Civil Engineers; E. D. Hardy

Table 14—(*Continued.*)
(C) Totals.
Month.	Office and laboratory.	Pumping station.	Filter Operations:		Parking (care of grounds).	Experimental filters.	Main office.	Total.
Month.	Office and laboratory.	Pumping station.	Sand handling.	Repairs, etc.	Parking (care of grounds).	Experimental filters.	Main office.	Total.
1909.
July	$0.73	$0.57	$0.87	...	$0.31	...	$0.15	$2.63
August	0.76	0.64	0.59	...	0.78	...	0.15	2.92
September	0.88	0.98	0.84	...	0.52	...	0.20	3.42
October	0.80	0.77	0.86	...	0.80	...	0.10	3.33
November	1.00	1.54	0.52	...	0.72	...	0.20	3.98
December	0.93	0.86	0.32	...	0.41	...	0.17	2.69
1910.
January	0.93	1.37	0.47	...	0.15	...	0.10	3.02
February	1.01	2.62	0.53	$0.07	0.12	...	0.17	4.52
March	1.18	1.09	0.31	0.07	0.18	...	0.13	2.96
April	1.11	2.05	0.59	0.03	0.65	...	0.15	4.58
May	0.92	1.44	0.38	0.03	0.66	...	0.20	3.63
June	1.42	2.90	0.38	2.16	0.84	...	0.16	7.86
Average.	0.97	1.39	0.29	0.46	0.58	...	0.16	3.80
Fiscal years:
1905‑1906	0.49	1.04	0.49	0.02	0.01	...	0.09	2.14
1906‑1907	0.60	1.24	0.66	0.41	0.09	$0.03	0.04	3.07
1907‑1908	0.75	1.13	0.46	0.39	0.21	0.09	0.10	3.13
1908‑1909	0.82	1.30	0.46	0.52	0.40	0.01	0.15	3.66

The two preliminary filters were operated at a rate of about 50,000,000 gal. per acre per day, and the three slow sand filters at rates of from 3,000,000 to 4,000,000 gal. per day.

This plant was put in service during the early part of February, 1907, and was kept in practically continuous operation until the end of July, 1908.

Table 15—Average Cost for Labor for Sand Handling.
(A) Per Million Gallons Pumped To Filter.
Month.	Scraping.	Ejecting.	Washing.	Smoothing.	Raking.	Re-Sanding.	Total.
1909.
July	$0.10	$0.21	$0.03	$0.02	...	$0.21	$0.57
August	0.07	0.16	0.03	0.01	...	0.04	0.31
September	0.05	0.13	0.02	0.01	$0.01	0.27	0.49
October	0.06	0.15	0.03	0.01	0.02	0.12	0.39
November	0.02	0.06	...	...	0.02	...	0.70
December	0.02	0.04	0.01	...	0.01	0.01	0.09
1910.
January	0.04	0.07	...	0.01	0.02	...	0.14
February	0.04	0.10	...	0.01	...	0.02	0.17
March	0.04	0.06	...	0.01	0.01	0.05	0.17
April	0.10	0.15	0.04	0.01	0.02	0.06	0.38
May	0.02	0.03	0.01	...	0.01	0.11	0.18
June	0.02	0.04	...	...	0.02	0.01	0.09
Average	0.05	0.10	0.01	0.01	0.01	0.08	0.26
Fiscal years:
1905‑06	0.06	0.29	0.02	0.06	...	0.04	0.47
1906‑07	0.07	0.20	0.05	0.02	...	0.24	0.58
1907‑08	0.09	0.14	0.03	0.01	0.02	0.13	0.42
1908‑09	0.07	0.15	0.03	0.01	0.01	0.14	0.41

Table 15—(*Continued.*)
(B) Per Cubic Yard of Sand.
Month.	Scraping.	Ejecting.	Washing.	Smoothing.	Raking.	Re-Sanding.	Total.
1909.
July	$0.08	$0.15	$0.03	$0.01	...	$0.10	$0.37
August	0.07	0.15	0.03	0.01	...	0.11	0.37
September	0.07	0.17	0.03	0.01	...	0.17	0.45
October	0.06	0.15	0.03	0.01	...	0.09	0.34
November	0.10	0.23	0.02	0.02	...	...	0.37
December	0.12	0.25	0.04	0.02	...	0.08	0.51
1910.
January	0.10	0.19	...	0.02	...	...	0.31
February	0.07	0.15	...	0.01	...	0.09	0.32
March	0.06	0.11	...	0.02	...	0.08	0.27
April	0.07	0.09	0.03	0.01	...	0.05	0.25
May	0.06	0.09	0.03	0.01	...	0.06	0.25
June	0.06	0.12	...	0.01	...	0.10	0.29
Average	0.07	0.14	0.02	0.01	...	0.10	0.34
Fiscal years:
1905‛06	0.07	0.35	0.04	0.07	...	0.14	0.67
1906‑07	0.06	0.19	0.03	0.02	...	0.17	0.47
1907‑08	0.09	0.15	0.03	0.01	...	0.14	0.42
1908‑09	0.06	0.14	0.03	0.01	...	0.13	0.37

For convenience in referring to the different systems, the combined rapid and slow sand filter will be designated as Filter Plant No. 1, the combined Maignen scrubber and slow sand filter as Filter Plant No. 2, and the combined coagulating basin and slow sand basin as Filter Plant No. 3.