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5 <br />1 B• ALTERNATIVE SEWAGE TREATMENT SYSTEMS <br />2 This item was presented to provide and summarize available <br />3 information on the reliability of alternative sewage treatment <br />4 technology. <br />5 County Engineer Paul Thames presented information about the <br />6 Hazen & Sawyer Report on Alternative Treatment Systems. He distributed <br />7 a handout which listed a case study summary on alternative treatment <br />8 systems as well as conclusions and recommendations from the report. <br />9 Paul Thames explained that a small wastewater treatment <br />10 system, in terms of the report, range in size from 4,000gpd to <br />11 150,000gpd. This is the permitting size which is sometimes larger than <br />12 the size that is actually needed. <br />13 In answer to a question from Commissioner Gordon, Thames <br />14 explained that there are two kinds of discharge systems -- package <br />15 plants and septic tank /sand filter systems. The septic tank /sand filter <br />16 system has a conventional gravity septic tank which discharges into a <br />17 large container filled with sand. The liquid waste filters through the <br />18 sand and solids are removed. It also receives some additional treatment <br />19 from microbiological activity. The package treatment plant is a <br />20 prefabricated unit which uses many of the same treatment processes as <br />21 do larger municipal treatment plants such as Hillsborough's, OWASA's or <br />22 Durham's. <br />23 A discharging system discharges from a single point to the <br />24 surface waters. A nondischarging system can be spray irrigation onto <br />25 the surface of the ground or be injected by subsurface means. He <br />26 explained how the conventional septic system discharges into a <br />27 nitrification field. <br />28 Commissioner Halkiotis referred to a list of possible <br />29 problems which lead to violations of the operating permit and asked <br />30 about the validity of the statement that the technology of alternative <br />31 waste treatment processes is technically sound. Thames explained that <br />32 when a system is designed, the ultimate use of the system should be kept <br />33 in mind and that insuring the design is carried out as intended requires <br />34 that the designer monitor the construction to be sure it is constructed <br />35 correctly. What has happened is that the systems have been installed <br />36 without the designer monitoring construction. After the system was paid <br />37 for, the original design engineer was never involved again. The system <br />38 construction was turned over to the developer or contractor who had <br />39 other priorities for spending their money. The procedure now is that <br />40 all permits issued by the Division of Environmental Management require <br />41 systems to be designed by a professional engineer who must certify that <br />42 the system is built in accordance with the approved plans. In terms of <br />43 operation and maintenance, DEM looks at these systems once a year and <br />44 sometimes they don't even do that. On many systems when the maintenance <br />45 is neglected, they begin to fail. <br />46 Health Director Dan Reimer explained the proposed Monitoring <br />47 Program for alternative and conventional waste treatment and disposal <br />48 systems. He explained, with the use of overhead transparencies, seven <br />49 types of systems. He listed some of the responsibilities and the <br />50 department who has the authority for each of these seven systems and the <br />51 authority they recommend. <br />52 <br />