Sewage overflows can have significant environmental consequences, they can result in reductions of water quality in streams, rivers and can pollute groundwater. When sewer back-ups and overflows occur, it is possible that the waste can enter stormwater drains and flow into the ocean. These contaminants can cause depletion of oxygen residing within natural waterways causing harm to the aquatic life dependent on the oxygen.
In addition to spoiled water supplies, flood from sewers rich in fats can lead to significant land contamination and may result in the need to replace large areas of soil should a spill occur. Furthermore, additional energy is required by waste water treatment works to treat contaminated water and blockages, often with the use of non-biological chemical treatments.
Every year, there are approximately 200,000 blockages in sewers across the UK, at an annual cost of £15 million. An additional 7000 FOG related floods are reported each year in residential homes, resulting in huge clean-up costs. Costs that will be paid for through the increase of customer bills. There may also be significant social and economic impacts on individuals and businesses.
If properties have been flooded with sewer water, clean-up will be unpleasant and costly. Furthermore, given the potential of used cooking oils and animal fats for the production of biodiesel, as much as 20% of UCO is being stolen from catering and food production sites. The legitimate biodiesel industry believes that the biodiesel black market is costing the Treasury £25 million a year in lost revenue.