1. Inorganic & Organic Pollution Organic Pollution Inorganic Pollution

2. What is Organic Pollution? The main types of organic waste are: Sewage Silage Animal slurry: urine and faeces washed off farmyards and fields Food processing waste Chippings from paper mills Effluent from leather tanneries Organic pollution is when human activity allows organic compounds to enter a water body which causes harm to the ecosystem The leather tanneries in Morocco Urine is used to treat the skins slurry These wastes are rich in organic compounds such as proteins, lipids and carbohydrates

3. Pollution Sources These organic wastes can be released from either point or diffuse sources The two photos below show these different sources. Which is which? With the exception of plastics (e.g. in sewage) and some man- made chemicals, these wastes are largely biodegradable If this waste enters a water body, anaerobic decomposers such as bacteria and fungi will begin to break down the waste….. Diffuse sourcePoint source Pollution across a large area Pollution from a specific point

4. Manure and Silage Manure and silage are two important organic pollutants Manure is egested faeces and contains organic matter (e.g. indigested grass), as well as hormones, antibodies and heavy metals Silage is grass which has been anaerobically digested by bacteria and which then can be used to feed livestock – it is stored in bags Silage is rich in proteins, lipids and carbohydrates as well as phosphates Why has the volume of silage increased? intensive livestock farming has become more common Why has the volume of silage increased? intensive livestock farming has become more common

5. Manure and Silage If either manure or silage enter water bodies then bacteria will rapidly feed on the wastes, reducing the O 2 content. What is produced In this process? Ammonia What is produced In this process? Ammonia Bacteria multiply Oxygen removed Organisms, e.g. fish, die Organic matter decays Manure or silage sedimentation Waste needs to be treated as for earlier sewage pollution Or this can be avoided by collecting the flushings in ponds; both the water and the nutrients can then be recycled via irrigation water. Click Here Click Here flash animation

6. Sewage Pollution Sewage is a “mix of domestic and industrial waste in liquid form” But what is sewage comprised of? SEWAGE DEBRIS e.g. plastics DISSOLVED ORGANIC MATERIAL e.g. bacteria, urine, soap WATER (up to 99.9%! DISSOLVED INORGANIC MATERIAL e.g. N, P PARTICULATE ORGANIC WASTE e.g. food, goldfish

7. Sewage Pollution In the developed world, the quantity of raw sewage output is approximate 150-200 gallons per person per day (600-800 litres). Raw sewage may also contain variable amounts of pesticides, heavy metals and other toxic compounds because people pour unused portions of products down sinks

8. Problems of Sewage DISEASES CHOLERA SALMONELLA E. Coli POLIO HEPATITIS A These diseases are common in LDCs due to lack of water treatment TYPHOID FEVER Contains pathogens-organisms (e.g.microbes) capable of causing disease Can you name some of the diseases that might be carried by sewage?

9. Sewage Treatment 1. Screening Screen removes large materials e.g. paper/ vegetable cuttings 2. Initial sedimentation Coarse solids e.g. grit settle out Some OM may flocculate (clump together) and also settle The sediment - primary sludge - may be allowed to accumulate in the sedimentation tank for weeks to allow some microbial breakdown of the OM The supernatant – unpleasant smelling turbid liquid is passed on at intervals into either a trickling filter bed or an activated sludge treatment tank

10. Sewage Treatment 3a. Trickling filter bed is made of graded stones, grit and clinker covered with bacteria, fungi and protozoa As the effluent trickles slowly over the bed the fauna digest the OM and in turn other organisms e.g. predatory protozoa, nematodes and insect larvae eat these microorganisms By the time the effluent drains from the bottom of the bed, most OM has been degraded to mineral salts 3b Activated sludge treatment An additional starter culture of microorganisms are added, speeding up and increasing the effectiveness of the process Stirring/aeration increase O 2 levels to stimulate respiration After several hours the biochemical oxygen demand (BOD)  by 90%

11. Sewage Treatment 3.Secondary sedimentation The solids and microorganisms are allowed to settle 4. Tertiary treatment Involve adding iron sulfate to remove phosphates microstraining to remove any remaining bacteria before being returned to a river 5. Anaerobic digestion The sludge from the first and second sedimentation tanks is passed into an anaerobic digestion tank for treatment before disposal Anaerobic microorganisms break down the sediment, eventually producing methane which can be used as a power source Remaining sediment is dried and can be used for landfill or fertilisers

12. Sewage Treatment There are a number of stages to the treatment process: screening Flocculation and settling Grit trap Clean water to rivers Trickle beds (aeration) sewage landfill O 2 added debrisheavy sediment to sludge digestion

13. Inorganic Pollution Title Page

14. Nitrate & Phosphate Pollution Low availability of N&P limits plant growth, so farmers add nitrate and phosphate fertilisers Nitrates are highly-soluble, phosphates erode Such pollution has increased as farmers increasingly grow winter (e.g. sugar beet) as well as summer crops. Only 40% of nutrients are used by crops in the winter (72% in the summer)

15. Effects of Nitrate Pollution Blue-baby syndrome (methaemoglobinaemia) If large amounts of nitrates in water are ingested by an infant they are converted to nitrite The nitrite reacts with oxyhaemoglobin (O 2 carrying blood pigment) to form methaemoglobin, which cannot carry oxygen Body tissues may be deprived of O 2,  blue coloration of mucous membranes & digestive/respiratory problems Concentrations > 100 mg l -1 of NO 3- potentially form nitrosamines (carcinogens) in the stomach  stomach cancer

16. Eutrophication Click Here Click Here flash animation

17. Control of Nitrates 1.Agricultural techniques avoid fallow periods esp. autumn and winter by sowing cover crops. nitrate fertiliser should be applied (e.g. spring) to ensure maximum uptake by plants animal manure should not be used in autumn and winter grasslands should be ploughed on a small-scale or not at all 2. Slow release fertilisers - excess fertilisers can be leached 3. Nitrate treatment plants Water is passed through an ion - exchange resin which removes nitrate ions and replaces them with chloride ions expensive and complex process 4 main controls

18. 4. Nitrate Sensitive Areas (NSAs) introduced from 1990 in 32 areas across the UK KEY NSA SCHEME Distribution of the NSAs Control of Nitrates How do they work? Farmers receive payments to reduce fertiliser and manure applications, avoid autumn application of fertilisers and autumn ploughing How do they work? Farmers receive payments to reduce fertiliser and manure applications, avoid autumn application of fertilisers and autumn ploughing Aims: reduce/stabilise high NO 3 - levels in public water supplies via changes to farming activity ensure that the abstracted water meets the EU 50 mg/l -1 limit for NO 3 -

19. Control of Phosphates Phosphate Stripping Primary sewage treatment removes 5 – 15% of nutrients. Secondary sewage treatment removes 30 – 50% of nutrients. Phosphates are precipitated using coagulants of lime or compounds of Fe/Al. 90-95% efficient. OrPhosphate-containing waters are passed into a lagoon or pond. If the water is retained for 3+ days, nutrients will be taken up by algal blooms  these will transfer phosphate to the sediment. OrDuckweed or water ferns can be used to absorb phosphates from ponds.