A project has been underway which attempts to demonstrate practical means of abating pollution from coal mine mineral wastes. The site included a refuse pile occupying approximately 40 acres and a slurry lagoon complex of 50 acres. In the report, the characteristics and acid formation rate of the refuse pile are described. The average rate of acid formation for this refuse pile is 198 pounds of acidity, as CaCO₃, per acre per day. Acid contribution from the slurry lagoons was not determined but appears to be negligible. As an abatement measure, a number of experimental vegetative covers were tested. Grass was successfully established with and without the use of topsoil, weathering well for one year. The long-term effects of establishing a grass cover directly on the refuse without the use of topsoil are not known at this time.

A pilot scale field investigation of the effects of supplemental aeration on waste stabilization lagoons was conducted at Laramie, Wyoming, a low temperature, high altitude area. Both batch and complete mixed experiments were conducted using constant air flows. Loading rates, both hydraulic and process, were varied. The supplemental aeration provided both aeration and mixing, thereby increasing metabolic rates. BOD reductions varied from 72 to 85% under three different loadings, at temperatures of less than 12°C. No settleable solids were found in the effluent from the aerated system. Series operation was demonstrated to have the advantages of damping variations in quality parameters, providing for shock loading, and reducing coliform counts to minimum levels.

Experimental studies were undertaken to examine the flow in long vertical conduits with particular reference to the design of storm water drop shafts. A distinguishing characteristic of such flow is the potential cavitation regime. Its existence depends upon the design of the structure. The cavitation regime will develop when the conduit is sufficiently long and the head sufficiently large. It can also be generated at a lower head if a control valve is installed in the supply line so that the net head can be negative. If a small amount of air is introduced into the system, the cavitation region is eliminated, the pressure gradient is more uniform, and the flow consists of a uniform mixture of air and water.

Studies were undertaken on a small scale to determine the effect liquid waste artificial iron-rich acid brines had on municipal sewage treatment processes. The brines were devised to simulate concentrates from treatment of acid mine drainage. At very high concentrations, the brines neutralized with lime give virtually complete removal of phosphate from primary effluent, activated sludge effluent, or anaerobic sludge digester decantate. The cost of the iron-rich acid brine produced from acid mine drainage by the reverse osmosis membrane treatment is estimated. Costs of transportation by rail, truck, and pipeline are also shown.