Parts per 1,000,000. +----------------------------------------------------------------------------+ ¦ ¦ November 23, 1900 ¦ +----------------------+-----------------------------------------------------¦ ¦ ¦ Chemical Precipitation ¦ Filter-beds ¦ +----------------------+--------------------------+--------------------------¦ ¦ ¦Sewage¦Effluent¦Efficiency¦Sewage¦Effluent¦Efficiency¦ +----------------------+------+--------+----------+------+--------+----------¦ ¦Oxygen consumed: ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ Total ¦ 38.3 ¦ 23.2 ¦ 40% ¦ 23.2 ¦ 14.3 ¦ 38% ¦ ¦ In suspension¦ 27.2 ¦ 12.1 ¦ 55% ¦ 12.1 ¦ 3.5 ¦ 71% ¦ ¦ In solution ¦ 11.1 ¦ 11.1 ¦ 00% ¦ 11.1 ¦ 10.8 ¦ 3% ¦ ¦Nitrogen as albuminoid¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ammonia ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ Total ¦ 8.32 ¦ 4.00 ¦ 52% ¦ 4.00 ¦ 2.46 ¦ 38% ¦ ¦ In suspension¦ 7.12 ¦ 2.56 ¦ 64% ¦ 2.56 ¦ 1.60 ¦ 37% ¦ ¦ In solution ¦ 1.20 ¦ 1.44 ¦ –20% ¦ 1.44 ¦ .864 ¦ 40% ¦ ¦Total organic nitrogen¦15.30 ¦ 5.32 ¦ 67% ¦ 5.32 ¦ 3.56 ¦ 33% ¦ ¦ In suspension¦12.48 ¦ 1.86 ¦ 85% ¦ 1.86 ¦ 1.54 ¦ 17% ¦ ¦ In solution ¦ 2.82 ¦ 3.46 ¦ –23% ¦ 3.46 ¦ 2.02 ¦ 42% ¦ ¦Nitrogen as free ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ammonia ¦ 32.0 ¦ 32.0 ¦ 0% ¦ 32.0 ¦ 32.0 ¦ 0% ¦ ¦Nitrogen as nitrites ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦Nitrogen as nitrates ¦ .120 ¦ .240 ¦ ¦0.240 ¦ 0.60 ¦ ¦ ¦Chlorine as chlorides ¦ 134 ¦ 136 ¦ ¦ 136 ¦ 119 ¦ ¦ +----------------------------------------------------------------------------+ Another example of the use of chemical precipitation is at Alliance, Ohio. There are three tanks each with a capacity of 144000 gallons. The amount of sewage flowing into the tanks during the year 1897 averaged about 300,000 gallons per day. During the year 1897 each day 180 pounds of chemicals were added to the sewage and 650 pounds of sludge was precipitated and pressed daily. The total cost of the disposal plant was $20755.00. The cost of operation and maintenance for the years 1897 and 1898 was $1290.00 and $1567.43 respectively. The average amount of lime used during this time was 95000 pounds yearly. Two men perform all the labor necessary for the operation of the plant. From the chemical analyses given in the Engineering Record Jan. 13, 1900 of the sewage and effluent, averages representing five months show the efficiency in albuminoid ammonia to be 40 percent and oxygen required 30 percent.