Sewage fertilisation

Chemical pollution From a qualitative point of view, an important common issue is the excess of chemicals (fertilisers and pesticides) associated with agrarian and livestock farming diffuse sources and the point-source discharge of (treated and untreated) sewage water. Industrial point-source pollution is not addressed as a relevant issue, but it is assumed that industries operate following the legal rules and only the incomplete elimination of industrial chemicals in urban wastewater treatment plants is perceived as a problem. 

Although the nutrient content of wastes makes them attractive as fertilisers, the application of many industrial wastes and sewage is constrained by the presence of heavy metals, hazardous organic chemicals, salts and extreme pH values. 

Sewage sludge contains significant concentrations of nutrients, particularly N and phosphorus and is recognised as having considerable potential as a fertiliser material and soil conditioner. Concentrations of nutrients vary considerably between sludges. Sommers [4], reported ranges of <0.1-17-6% for total N, <0.1-14.3% for total P, and 0.02-2.64% for total potassium. 

Safety margins of 78-131 for fertilisation of agricultural fields with sewage sludge were calculated. 

Under the pressure of progressively more stringent government regulations with regard to permissible levels of residual NH3 and urea content in wastewaters, the fertiliser industry made an effort to improve wastewater treatment (see also Water, sewage). 

The wide distribution of eggs of cestodes of all classes in soil, sewage or water makes the application of ovicides as a method of control generally impractical. Various aspects of the effects of ovicides and/or fertilisers on... 

Possible solutions include the use of inorganic fertilisers or imported topsoil, which can be very expensive depending on location and availability. An alternative solution is the use of organic wastes such as sewage sludge, which is already used in the UK as well as Sweden and Finland. 

Eriksson, J. (2001). Concentrations of 61 trace elements in sewage sludge, farmyard manure, mineral fertiliser, precipitation and in oil and crops. 5159, Swedish Environmental Protection Agency, Uppsala, Sweden available on internet at the URL www.naturardsverket.se/pdf/620-6246-8.pdf. 

DETERMINATION OF THE TRANSFER OF TRITIUM TO CROPS FERTILISED WITH CONTAMINATED SEWAGE SLUDGE... 

Many farmers use treated waste from sewage farms as a fertiliser. Some farmers use their own animal waste material to generate methane gas which can be used for domestic and farm heating supplies. Any solid material left is used as a fertiliser. 

The supply of the coppice will be undertaken by Yorkshire Environmental Ltd., which will try to maximise the utilisation of biomass fuels supplied by short rotation forestry. Slurry of domestic treated sewage sludge supplied by Yorkshire Wafer Services Ltd. will be applied to the coppice plantations as organic fertiliser to increase crop yield. The sludge will be low in heavy metal, pathogens and odour. Waste ash from both the gasifier and the catalytic cracker will be recycled to the coppice plantations as a soil conditioner and source of base cations and micronutrients to improve soil fertility. 

The method with azomethine H has been used for determining boron in plant materials [75], biological samples [76], plants [77], soils [77-79], water [80], sewage [4,81], rocks and bituminous [22,55,82], steel [47], copper, nickel, and cobalt alloys [9], boron nitride [83], and fertilisers [84]. Azomethine H has been utilized in automatic determination of boron [81] and in flow injection analysis (FIA) [75]. Boron has also been determined in plants and soils with the use of 4-methoxyazomethine H [85],... 

Frozen vegetables may have total counts of up to 100000 g. Exotic imported vegetables should be tested for coliforms, E. coli and enterococci as human waste is widely used as a fertiliser in Asia. Cress has also been implicated in a number of food poisoning incidents and should be tested for E. coli, as it may have been grown in water polluted with sewage. 

The comparatively high nitrogen and phosphorus contents of some sewage sludges render them suitable for fertilisers (Chapter 12.2). Fly-ash from municipal incinerators can have a P content of 0.5-1.0 wt% [61,73] (Table 2.14). 

Eutrophication The release of nutrients, mainly nitrogen and phosphorus, from sewage outlets and fertilised farmland causes nutrient enrichment. This results in an altered species composition in nutrient-poor habitats and in algal blooms in water bodies, causing a lack of oxygen and fish death... 

Since sewage sludge contains nitrogen and phosphate, and therefore has some fertiliser value, and municipal compost contains organic matter, there is no... 

Cadmium is commonly present in sewage sludges, sometimes in quite high concentrations of the order of 100 ppm in the dry matter. Since this material is now being actively promoted as a fertiliser in the interests of disposal, it seems inevitable that there will be increases in the concentration of this metal in food marketed for human consumption as a result of cadmium contamination of agricultural soils. It is already clear that the uptake of cadmium by plants... 

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