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The Washington Suburban Sanitary Commission performed a study comparing different biosolids management options for its Wastewater Treatment Plants with a focus on energy recovery from biosolids through the methods of drying followed by either gasification or anaerobic digestion with combined heat and power generation. The three phased approach consisting of identifying and screening technologies, performing detailed economic and noneconomic analysis of short listed options, and developing a concept design report for the selected option. Several drying and gasification alternatives were screened but only closecoupled systems were short listed for further analysis. Multiple anaerobic digestion configurations and pretreatment technologies were also screened leading to a short list of conventional mesophilic anaerobic digestion, acid-gas phase digestion and 2PAD. The thermal hydrolysis process was determined to be the most cost effective pretreatment technology to maximize digester gas production. The concept design report was based on a regional facility serving four of the five WWTPs and expandable in the future to accommodate the fifth WWTP.

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. The report covers both meetings. M r A. S. CoornbsThe scheme was completed in 1966 but was conceived in 1945, and since then there have been six Divisional Road Engineers of the Wales and Monmouth Division of the Ministry of Transport, in whose area the road lies. I went to Wales as DRE in 1963 and was there when the first Secretary of State for Wales, with complete autonomy for roads, was appointed.87. New roads, particularly this one, have their problems in the planning, design and construction stages, but I have also to live with this completed road and with the many day-to-day problems that arise from its use. 88. The road, even with increasing traffic flow, has now an accident rate well below that given in the Paper (in 1968 it was 0.47/milIion vehicle miles), which makes it much safer statistically than a motorway. This relative safety is due perhaps in no small measure to the adverse publicity which has been given to it by the press and by local authorities along its route, both individually and collectively, so that most of the drivers using it are fully aware of its hazards and drive accordingly. The real reason is I think that the road has been deliberately designed and built as a three-lane road and not just widened from a substandard two-lane road. This has been done in the past and has provoked much criticism, which in many instances has been justified. (0 28) there are references to differences in the type of specification of the surfacing on the steeper parts of the road towards its western end, compared with the remainder. Here 100% lake asphalt was used in the surfacing. Was there a large price differential between that 100% lake asphalt and the 50/50 lake asphalt/residual bitumen mixture which was used on the remainder of the road? If there was, could the Authors say whether the extra lake asphalt which was used on the steep parts was worthwhile?* 90. The Pant Viaduct is constructed of steel beams with composite deck. There has been some cracking of the asphalt at the joints of this bridge. In general, the joints and the backs of the abutments have stood up remarkably well but there is a little trouble at the joint at the free end and water is leaking through. As all the other bridges are trouble-free, could either of the Authors give the reason for this? Is it due to the difficult ground conditions that pervade the immediate area of the Pant Viaduct or to the greater temperature susceptibility of the exposed steel in the construction of the deck? In all other cases concrete was used. M r R. H. Deniels, County Surveyor, Breconshire County CouncilWould the Authors comment on the adequacies of the design standards for this threelane carriageway, and whether, in view of the long delay which has occurred since the inception of the scheme and the date of completion, opportunities should not perhaps