Roger Hedgepeth, Mayor.  Welcome.

Adele Schirmer, Director of Planning and Engineering, Town of Blacksburg.  Introduction.

John Novak, Ph.D.   Dept. of Civil and Environmental Engineering, VT

Overview of decentralized wastewater systems.   Reviewed the various types of decentralized systems available and noted the advantages and disadvantages of each.   Whereas maintenance is routinely performed on large systems, it is often neglected on smaller systems, which can lead to system failures.  Clustered subdivision systems can perform better than individual systems.   Reviewed problems in the older types of decentralized systems, noting that newer technologies employing combinations of approaches were most promising.

Donald Alexander.  Virginia Department of Health.

Reviewed the new Department of Health regulations regarding wastewater, scheduled to go into effect October 1, 1999.  These new regulations: 1) encourage decentralized and innovative wastewater systems by reducing restrictions on the number of systems using new technologies, by creating a new class of provisional systems based on science where performance data exists [there is such data on 50 such systems], and by recognizing research.  2) allow private engineers to take the place of VDH specialists in making recommendations for system specifications for a house lot and pass these recommendations on to VDH. 3) increase the drainage field depths required from 2" to 18" for depth of soil to the water table and from 12" to 18" for the depth of soil to rock.   These required depths, however, can be significantly lowered through use of pretreatment.  Virginia now recognizes pre-treatment.  Pretreatment, which previously was not encouraged now is encouraged in certain circumstances.

Other observations: Central sewer systems push water out of the hydrological cycle, while decentralized systems replenish the water table.  There are big on-site systems now at Smith Mt. Lake and Virginia Beach.  The bigger the system, the more closely it should be monitored.

Comments on conventional septic systems: Current state regulations establish standards for the design and installation of septic systems but none for maintenance once the system has been installed.   Yet when failures do occur, the problem is usually lack of maintenance.  With minimal maintenance, conventional septic systems perform well at appropriate sites.   The new regulations encourage designs that facilitate maintenance, e.g., septic systems that do not have to be dug up with a back hoe for inspection or pumping.