Hampshire, Portsmouth and Southampton

Minerals and Waste Local Plan:
Adopted December 1998

Waste Water (Sewage) and Sewage Sludge

Main Contents Page

Need for Waste Facilities

Clinical Waste

6. Meeting the Need for Waste Management

Non-Inert Waste Scenarios

Scrapyards

General Considerations

Inert Waste Scenarios

Waste Water (Sewage) and Sewage Sludge

Waste Arisings

Landfilling and Landraising

Ancillary Waste Development

Waste Minimisation and Recycling

Waste Processing

 

Resource Recovery

Difficult and Special Waste

 

6.90 Apart from the relatively small quantities collected by waste companies and some District Councils from cess pits and septic tanks, all waste water (sewage) arising in Hampshire is handled and treated by the three water companies - Southern Water, Thames Water and Wessex Water. It is estimated that some 30,000 million gallons of waste water is generated each year in Hampshire. The majority of this is handled by Southern Water, which covers most of the County, including the large urban areas of south Hampshire. In 1994 the waste water treatment works operated by Southern Water produced approximately 23,000 tonnes of dry sewage sludge. In 1991 this was disposed of in the following ways: 55 per cent on land (mainly spreading on agricultural land); 34 per cent to the sea (by ship); and 11 per cent by incineration (at the Peel Common, Fareham sewage sludge incinerator). Southern Water operates some plants along the Hampshire coast which currently discharge waste water to the sea following preliminary treatment (coarse filtering) only.

6.91 The European Community Urban Waste Water Treatment Directive (91/271/EEC) has two major implications for the treatment of waste water and the disposal of sewage sludge which will have effect within the Plan period. Firstly, it requires the cessation of sewage sludge disposal at sea by 1998. Secondly, secondary treatment is required by 2000 for waste water treatment works with population catchments over 15,000 which discharge effluent to sea; and by the end of 2005 for works with population catchments between 10,000 and 15,000, depending on the classification of the receiving water.

6.92 Within Hampshire these requirements only apply to Southern Water. Firstly, Southern Water needs to find an alternative means of disposal for the approximately 13,000 tonnes of dry sewage sludge that were disposed of at sea (1994 figure). Secondly, new waste water treatment works will be required to provide secondary treatment for the waste water which is currency discharged to the sea at Eastney (Portsmouth) and Ashlett Creek (Fawley). It is estimated that these new works, together with the recently completed works at Lower Pennington (Lymington), will generate an additional 7,300 tonnes of dry sewage sludge, mostly from Portsmouth, which will require treatment and disposal. Therefore a total of approximately 20,300 tonnes of dry sewage sludge will require new provisions for disposal. In addition, in the light of developing legislation and public opinion, the current practice of applying raw liquid sewage sludge directly to agricultural land may be reviewed. This could lead to a requirement for additional treatment and disposal provision at waste water treatment works in the parts of the County away from the coast. Population growth and new development may also lead to a need for new or improved waste water treatment facilities.

6.93 Southern Water has identified possible sites for new waste water treatment works at Eastney and Ashlett Creek and has requested the County Council to safeguard these sites in this Plan. Sites for the Eastney Waste Water Treatment Works are safeguarded in the adopted Portsmouth City Local Plan (1995). In February 1995 the County Council granted planning permission for the construction of a new waste water treatment works at Iley Lane, Lower Pennington (Lymington), which has now been constructed and was opened in 1998.

6.94 Southern Water has prepared a new strategy for sewage sludge for its Hampshire Division. This strategy takes account of the various treatment process and disposal options for sewage sludge, the availability of potential outlets for sludge products, environmental constraints and planning policies. Excluding sea disposal, there are three broad process and disposal options for sewage sludge: landfill; incineration; and beneficial after-use. Southern Water has stated that it is generally committed to a policy of beneficial after-use of waste products. There are a variety of products that can potentially be created from sewage sludge, but the most practicable options would seem to be the production of agricultural and silvicultural fertilisers or soil conditioners.

6.95 Mechanical dewatering of sludge can reduce the volume by about 70 per cent and creates a dry cake which can be transported safely and easily by lorry. The proximity of most waste water treatment works to houses and workplaces means that the reduction of sludge odour is necessary. Prior treatment of the liquid sludge, for example by digestion, will ensure the cake is relatively odourless. Treatment processes also kill the pathogens, bacteria and viruses present in waste water to produce a more stable material. The by-products of processing are liquors from dewatering, which must be returned to the waste water treatment works, and gases, which can be collected for use as a fuel and are usually utilised within the sludge plant. Processing therefore needs to be carried out at or close to a waste water treatment works. More advanced processes, to produce high quality fertilisers, include thermal drying, composting and mixing with other materials such as lime and straw.

6.96 Southern Water has carried out market research which indicates that the farmers within Hampshire are likely to be willing and able to use the quantity of sludge products generated. In addition, it is expected that some horticultural and silvicultural use may be made of sludge products. Application of sludge products to land is subject to annual limits imposed on levels of heavy metals and nitrogen in the soil. Agricultural use of sludge products is likely to be seasonal and to involve the distribution of relatively small amounts to a large number of users. Whilst production would be concentrated in south Hampshire, most usage would be in the central and northern parts of the County. A network of storage and transport facilities will therefore be required. It is also likely that some transportation of liquid raw sludges, probably by pipeline, between waste water treatment works will be necessary.

6.97 Since the quality and quantity of sludge may vary significantly from time to time, Southern Water considers that a flexible strategy is needed. This would include contingency provisions, for instance in the form of incineration or landfill capacity, to cater for occasions when sludge products cannot be applied to farmland. In general, Southern Water suggests that the following land-use requirements will arise:

6.98 Southern Water has requested that a number of its existing sites are safeguarded for possible development in line with future operational requirements. The potential scope of development which it is considered each site may be able to accommodate in future is summarised below:

6.99 The Councils recognise the need to ensure the necessary balance is achieved between meeting future needs of the wider community and environment for new development relating to waste water and sewage sludge treatment and disposal; and minimising the effect of such development on local communities and the local environment so as to ensure that it is not likely to give rise to any unacceptable impact. Therefore, permission will be granted for development necessary to meet operational requirements provided that it meets the general criteria set out in Policy 51. In the case of proposals for any of the sites listed in Policy 52, the site-specific planning issues set out in the text accompanying the proposals map inset maps should be addressed. A waste water treatment plant is included in Schedule 2 of the Town and Country Planning (Assessment of Environmental Effects) Regulations 1988 and, as such, a proposal which would be likely to have significant effects on the environment by virtue of such factors as its nature, size or location would be required to be accompanied by an Environmental Statement setting out the likely impacts of the proposed development and including an assessment of alternative development options and locations also considered in the formulation of the proposal. In the case of proposals for the treatment or processing of sewage sludge, details of the method and location of disposal of the product and the process residues and of any traffic movements involved will be required. With regard to odour from waste water and sewage sludge treatment plants, where appropriate the Waste Planning Authority will liaise with the appropriate District Council Environmental Health Officer and the relevant water company to ensure appropriate control.



6.100 Policy 52 safeguards the sites where Southern Water considers that new waste water treatment facilities will be required during the Plan period, at Ashlett Creek (Site Q) and Eastney (Site R). The Eastney site includes two separate areas of land for a treatment works and stormwater storage. Policy 52 also safeguards existing waste water treatment works sites put forward by Southern Water as possible locations for sewage sludge handling, treatment and processing development.

6.101 The Waste Planning Authorities will seek to safeguard all the sites in Policy 52 from other development and where appropriate will seek the co-operation of the relevant District Councils in doing this. The Waste Planning Authorities will not grant permission for such proposed development unless they are satisfied that no unacceptable adverse nuisance or other adverse environmental impact would be likely to be caused. In addition, the Waste Planning Authorities will encourage the water company involved to take the opportunity presented by such proposals to seek to resolve any problems arising from existing operations, where appropriate in co-operation with the relevant local authorities. Maps showing each of the sites to be safeguarded, together with a summary of the site-specific planning issues relating to each site, are set out in Appendix 1.

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