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

[³ Reservoir out of service from September 10th to October 4th, 1909.]

No chemical determinations were made during February, March, April, and May, 1910, on account of the rearrangement of the laboratory and equipment.

Table 7—Daily Results at Pumping Station.
(A)
Month.	Million gallons pumped:						Lift to filters.	Pressure at sandwasher pumps, per square inche.	Coal consumed per day in tons.			Station duty, per 100 lb. of coal consumed.
	To filters.			To sand washers.					Coal consumed per day in tons.			Station duty, per 100 lb. of coal consumed.
	Max.	Min.	Ave.	Max.	Min.	Ave.			Max.	Min.	Ave.	Max.	Min.	Ave.
1909.
July	76.16	57.65	64.05	1.140	0.298	0.730	24.18	110.0	13.4	8.4	10.8	67.8	52.3	61.4
August	69.31	54.44	61.42	0.629	0.157	0.441	22.18	110.0	12.4	8.0	10.1	64.2	49.5	56.6
September	66.02	52.82	69.32	0.831	0.207	0.572	22.26	110.0	12.7	8.7	10.5	61.0	48.9	55.1
October	78.50	48.12	59.18	0.761	0.060	0.467	21.84	110.0	13.4	8.0	10.3	59.6	49.1	53.6
November	64.92	49.83	55.25	0.468	0.141	0.272	20.49	110.0	11.3	7.9	9.2	55.6	45.7	51.1
December	67.83	48.32	56.77	0.307	0.039	0.174	20.54	110.0	10.3	8.5	9.5	61.0	45.4	50.4
1910.
January	70.04	51.02	62.49	0.499	0.008	0.156	22.43	110.0	12.7	9.1	10.4	59.6	49.8	54.9
February	70.79	55.19	60.28	0.284	0.041	0.173	21.44	112.3	12.3	8.7	10.2	57.4	44.8	51.5
March	59.11	51.64	56.04	0.409	0.063	0.171	19.76	120.0	10.5	7.8	9.2	53.2	45.2	49.8
April	66.53	53.79	58.32	0.715	0.167	0.474	20.78	120.0	11.1	8.1	9.7	58.7	47.2	53.7
May	61.93	54.55	57.76	0.525	0.059	0.251	20.30	120.0	10.1	7.4	8.8	60.7	48.1	54.9
June	70.49	50.42	58.37	0.281	0.124	0.207	21.19	117.3	12.3	7.4	9.1	60.1	49.9	54.4
Fiscal years:
1909-10	78.50	48.12	59.19	1.140	0.008	0.373	21.45	113.3	13.4	7.4	9.8	67.8	44.8	54.0
1905-06[¹]	80.59	57.18	66.07	2.062	0.089	0.747	21.71	107.4	14.8	6.4	8.9	79.6	48.2	62.8
1906-07	80.29	57.44	66.89	2.120	0.023	0.580	21.60	120.8	15.0	7.0	10.0	71.6	46.5	58.6
1907-08	80.38	54.35	64.91	0.735	0.017	0.347	22.20	125.0	12.0	7.2	9.6	70.7	51.3	60.3
1908-09	78.93	47.83	61.47	0.875	0.060	0.453	22.52	122.3	13.2	7.0	10.0	74.0	45.7	57.7

Fiscal Year.	Name of coal used.	Cost per ton.	Duty per 100 lb. of coal consumed.	Cost of coal per 1,000,000 ft-lb. of work performed.
1905‑06	George's Creek Big Vein	$3.34	62.8	$0.00238
1906‑07	George's Creek Big Vein	3.43	58.6	0.00261
1907‑08	George's Creek Big Vein	3.75	60.3	0.00278
1908‑09	Orenda	3.47	57.7	0.00268
1909‑10	Orenda	3.15[²]	54.0	0.00255

[¹ Raw water shut off from city supply on October 5th.]

[² Corrected for increase or decrease in ash and British thermal units, as determined by United States Geological Survey.]

**Table 8.—Average Consumption of Water for Twenty-Four Hours, Per Million Gallons.**
Month.	Fiscal years.
Month.	1903.	1904.	1905.	1906.	1907.	1908.	1909.	1910.
July	59.80	61.50	63.20	69.80	69.18	68.64	71.08	64.05
August	59.00	59.70	67.70	71.40	68.03	67.74	68.14	61.42
September	56.50	61.10	67.90	71.30	69.82	68.93	65.83	60.32
October	58.70	59.10	63.90	68.40	69.14	66.46	65.89	59.18
November	54.70	58.60	62.10	66.10	65.51	61.54	60.06	55.25
December	60.70	60.10	70.30	67.20	65.71	62.29	57.99	56.77
January	60.10	65.30	75.10	65.30	67.62	63.36	57.72	62.49
February	59.30	67.80	86.00	68.70	74.68	68.17	55.42	60.28
March	55.30	60.00	67.60	64.30	64.23	59.63	55.31	56.04
April	55.10	57.20	63.10	62.70	63.45	61.51	58.19	58.32
May	57.70	60.80	66.30	65.60	62.47	62.96	59.25	57.76
June	59.50	62.30	70.60	67.80	63.53	67.96	60.12	58.37

Average	58.03	61.10	68.70	67.40	66.90	64.91	61.47	59.19

The length of runs, depth of scraping, etc., after the scraping or raking, are shown in Tables [10] and [11].

Sand Handling.—For the first three years of operation, the sand was carried from the sand bins in carts and dumped through the numerous manholes of the filters on chutes which could be revolved in various directions, in order to facilitate the spreading of the sand evenly over the surface of the filter.

About a year ago, however, this method was changed, by substituting sand ejectors for the carts. By this method, an ejector is either attached to, or placed directly under, the outlet gate of the sand bin, the gate is opened, and the ejector is started. From this ejector, the sand is carried back through the line of 4‑in. fixed pipe, and one or more lengths of 3‑in. hose, to the point of discharge in the filter bed which is being re‑sanded.