How Is Sewage Treated ? from a noxious mixture of sedimentation where larger before disinfection, is sub solids and liquids into an organic solids settle out, Jcct to further treatment and effluent, or liquid discharge, leaving the first ac- various chemicals arc added that can be assimilated by cumulation of sludge. to precipitate out additional the receiving stream or Secondary Treatment solids, organics and river. The liquid is carried to phosphorous. The amount of Urge objects that find retention tanks and aerated, removal is directly their way into all sewage or mixed with air through proportional to the amount systems-boots, old tires etc.- the use of blowers. Aeration of chemical used, and are screened out. The provides the oxygen for tremendous quantities of sewage is sent to grit- scroblc bacteria, helpful sludge can be produced at removal chambers, where organisms that feed on the this point, sand and other coarse solids remaining in the Nitrogen also is removed inorganic particles settle sewage. This process forms in advanced systems, and at out. The sewage is then activated sludge containing least three different methods ready for primary a high concentration of (can be used)... aerobic bacteria. - Effluent from an advanced Some of the activated wastewater treatment sludge is recirculated system should be sparkling through new liquid entering clear and look like drinking the treatment system to water. Practically all provide for continuing oxygen- - 'demanding biological action; the rest is material, phosphorous and I sent to sludge disposal units, much of the nitrogen Jias As this process continues, been controlled. It is not the level of suspended solids regarded as drinkable, and biochemical oxygen although direct re-use is demand- the organic sub- under study, stances that deprive water of Sludge removed from the oxygen-are reduced. ( sewage during the various * This generally is followed phases of treatment is i by final settling or thickened ny one of two 1 sedimentation, which processed, then incinerated 1 produces still more sludge, or disposed of by any of If secondary treatment is several land-application the higest level purification methods, provided by a plant, the Sewage treatment plants remaining liquid is disin- that depend on biological fected, usually with chlorine, action (bacteria) for their then sent to a stream, purifiers can adversely be Secondary effluent is affected by toxic materials, reasonably clear, but still which can kill the helpful contains oxygen-demanding bacteria. In regional substances, phosphorous and treatment plants, where nitrogen and probably there are many treatment contains viruses. If properly tanks, it would be unlikely disinfected, odor problems that all could be knocked out should be minor. at once. Advanced Treatment Various methods of ad vanced treatment are (possible)... Generally speaking, the liquid sewage, Editor’* Note: In this era of development and ex pansion of sewer treatment plants, the following article on how sewage is treated is timely. ft is a condensation of an article in the Washington Post, based on information from the U.S. En vironmental Protection Agency and Washington Suburban Sanitary Com mission. Sewage treatment plants transform raw wastewater Parade of the Profit-Makers These Plus-Proven Sires Are Available Daily USDA (Nov./74) - 5.954 Daus. in 1,636 Herds Ave 15.329 M 3 52% Predicted Difference (99% rpt) +737N1 Type. H-FA (Oct /74) - 1.417 Classified Daus. Ave 79 1 (act), 1,080 Pr - Sire Osborndale Ivanhoe - EX & GM Dam. Kilmsdale Don Pansy - VG (88) 135 DAIRY SIRES ARE NOW AVAILABLE THROUGH OUR PROFESSIONAL TECHNICIAN SERVICE! BREEDERS COOPERATIVE LIVESTOCK SERVICES 15H114 Kilinsdale Ivanhoe JACK Very Good & Gold Medal Member NAL Affiliated Breeders TRY A CLASSIFIED 539 F -4F - 48 PDT CLEONA* Elizabethtown Hummelstown COATESVILLE' Parkesburg Oxford Pughtown Optimist Very Good & Production Qualified USD A (Nov./74) - 2,124 Oaus in 873 Herds Ave. ’ 14.985 M 3 55% Predicted Difference (99% rpt) +72OM +s4s Type: H-FA (Nov./74) - 314 Classified Daus. Ave 78.9 (act.). 218 Pr Sire: Lakefield Fond Hope - EX (93) & GM Dam; Glenafton Symbol N Bonheur 273-6763 367-3923 566-2569 384-2741 857-5545: 932-9361 469-9238 Lancaster Farming, Saturday, May 24.197 S my /-loss LBAK4. NAVO youß air coNPinoNiN& sysreM CHBCKBP WAN BKPSRT PROM 7)M£ TO TIME Want to Find a New Recipe? Read Home on the Range. For Your Dairy Herd: VG (89) Call for service and information: LANCASTER* Akron East Earl Gap* Mount Joy Quarryville ,*24-hour answering service or recorder E Berks* W Berks* YORK* 569 0411 859 2552 445-4131 442-4471 653-1451 786-7381 Brogueville Fawn Grove Seven Valley York Springs 9 1 532 F +BF - 56 PDT 376 8298 376-8297 , 792-0941 927-6210 382-4805 428-2266 528-4426
Significant historical Pennsylvania newspapers