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Three management options for the treatment of leachate from landfilled domestic solid waste have been evaluated. Research results show that leachate can be treated effectively in aerobic systems, with high organic carbon and ammoniacal nitrogen removals of >90% and >85% respectively. Optimum SRT of about 10 days is required. Anaerobic treatment (UASB) with HRT's of between 1.0 and 4.0 days results in COD destruction of about 85% with high methane production (400-600 mg/g COD removed) and provides an intermediate effluent suitable for polishing to a high standard. Recirculation of leachate through the landfill by itself cannot provide a complete treatment, although significant reductions in volume and strength of leachate can be obtained.

This paper highlights the main disinfection options available for sewage, final effluents and stormwater, and is a review of the current research programme being carried out by staff of the Water Research Centre.Disinfection is an increasing requirement, with particular emphasis on bathing and recreational water use. Laboratory and field trials are reviewed, and a wide range of disinfectants have been tested. These include peracetic acid and the Clariflow process for crude sewage; peracetic acid, ozone and UV irradiation for final effluent; and peracetic acid for stormwater.The efficacy of the various disinfectants is evaluated and general costs are presented. Of special interest is the potential effect of sewage strength in reducing the disinfecting properties of the chemical. It is also apparent that there are wide variations in performance between processes and host organisms.

The UK approach to pollution control in tidal waters places considerable emphasis on balancing the contrasting needs of utilization of the waters for the assimilation of effluents with the protection of all identified uses, i.e. the Environmental Quality Objective/Environmental Quality Standard (EQO/EQS) approach. In order to protect uses of the waters for bathing and general amenity, this approach in the design of improvement schemes necessary for marine sewage discharges is examined. However, recent guidelines for consent applications dealing with schemes designed to protect bathing use suggest a departure from the EQO/EQS approach towards an emission standard when dealing with the solid phase of the sewage effluent. The implications of these approaches are discussed from the design (scientific and engineering) viewpoints. A summary of headworks processes and the current practice for preliminary treatment at marine outfall sites in the UK is reviewed, together with comments on their effectiveness. The terms of reference and work of a joint working group to examine the efficiency of screening equipment at marine outfall headworks is described, together with a technical summary of results collected at a range of sites and with various types of equipment. Recommendations for future research are given, and a strategy for screening is developed.