GB1602300A - Composting additives - Google Patents

Description

(54) COMPOSTING ADDITIVES (71) We, PAN BRITANNICA INDUSTRIES LIMITED, a Company registered under the laws of England, of Britannica Works, Waltham Abbey, Essex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to composting, of grass cuttings.

Composting is a process wherein plant or animal matter is converted to organic manure by ambient, mesophilic and thermophilic micro-organisms, normally bacteria or fungi.

The metabolic requirements of these micro-organisms are well understood viz. water, available nitrogen, soluble carbohydrate, orthophosphate ions, sulphate ions, calcium, sodium, potassium, vitamins, trace elements and enzyme cofactors.

The traditional method of making compost is to make a heap outdoors of mixed garden waste to every 9"-12" (23-30 cm) apply an additive containing chalk and a source of readily available nitrogen, e.g. 40% chalk and 15% or more of an ammonium salt as a source of nitrogen. Sometimes household waste is also added to the heap.

Chalk is added to maintain a sufficiently high pH to ensure bacterial activity and the addition of nitrogen ensures that the synthesis of fungal/bacterial protein and the build up of bacteria is not restricted by shortage of nitrogen. The traditional method is carried out with the heap open or supported in a wire mesh, plastic or wooden bin.

It is well known that one of the most important conditions for successful composting is the carbon/nitrogen (C : N) ratio which should be in the range of 25 : 1 to 35 : 1.

The heap of mixed garden waste (and possibly household waste) used in the traditional compost heap has a C : N ratio which is usually in the range of 35 1 to 50:1. The addition of an additive containing available nitrogen brings the ratio down to the above optimum range.

With grass cuttings, which are readily available to most gardeners, the C: N ratio is in the range of 14:1 to 21: 1. so carbon rather than nitrogen is needed to bring the ratio up to the optimum. The only nitrogen required is a small quantity of readily available nitrogen to supply the metabolic needs of the micro-organism until composting proceeds sufficiently to release the nitrogen already in the grass.

Chalk, a major ingredient of traditional compost additives is not required for composting grass cuttings as we have found that a sufficiently high pH is achieved naturally. The presence of chalk therefore is undesirable as its use will lead to a too high pH and consequent loss of nitrogen as ammonia.

Grass cuttings are therefore not effectively composted with conventional additives.

Furthermore the traditional methods do not work well with grass unless the grass is mixed with more fibrous open structured material, such as straw, with a higher C: N ratio. When composted alone by the traditional methods, grass cuttings easily become compacted to form a wet anaerobic mass giving rise to objectional odours.

According to one aspect of the present invention, a composting additive for addition to grass cuttings to promote composting thereof comprises in excess of 60% by weight of starch and/or cereal meal as a source of carbohydrate, together with a source or sources of nitrogen and phosphate as nutrients for composting bacteria, the additive having a C:N ratio so as to bring the overall C:N ratio of the mixture of the grass cuttings and additive in a compost heap to 25 to 35:1. when applied in appropriate amounts. Examples of suitable cereal meal are barley meal, wheat meal, oat meal and corn meal. Mixtures of carbohydrate materials may be used.

The nitrogen source, which may be present in an amount in the range from 1 to 40%, preferably less than 10% by weight, ensures that the synthesis of fungal/bacterial protein and the build up of bacteria is not restricted due to shortage of readily available nitrogen.

The nitrogen sources may be urea, an ammonium salt (such as ammonium sulphate or nitrate), an alkaline metal or alkaline earth metal nitrate such as sodium or potassium nitrate, or calcium nitrate), or dried blood, may be used. Mixtures of nitrogen sources may be used.

The phosphate source may be present in an amount from 1 to 20% and in a form which readily yields orthophosphate ions. Suitable phosphate sources are superphosphate, double superphosphate, triple superphosphate, mono or diammonium phosphate. Mixtures of such materials may be used. The mono-and di-ammonium phosphate may be used as a combined source of readily availabe nitrogen and phosphate.

The additive may further comprise one or more optional ingredients for further accelerating the composting process. These will generally be of organic origin e.g. coffee waste, tea waste dried animal manure, hoof and horn meal, meat and bone meal, leather waste and seaweed meal and may be present in an amount from 1 to 50%.

A source of bacteria and/or enzymes may be also included.

Calcium carbonate, or its equivalent, is preferably absent from the additive.

Typical ranges of ingredients and proportions of the ingredients of the additive are as follows. All parts and percentages used in this specification are by weight unless indicated to the contrary.

Carbohydrate e.g. barley meal, wheatmeal, 5 - 90% Source oatmeal, cornmeal, starch, Nitrogen e.g. ammonium sulphate 2 - 40% Source ammonium nitrate 1 - 20% urea 1 - 20% Phosphate e.g. superphosphate (18% P205) 1 - 20% Source double superphosphate (P2O5) 1 - 10% triple superphosphate (44% P2O5) 1 - 8% monammonium phosphate 1 - 20% diammonium phosphate 1 - 20% Optional e.g. Coffee waste, dried manure 1 - 50% ingredients seaweed Bacteria/ enzyme source e.g.Saprophytic bacteria 0.01 - 2% of each of the bacterial culture and the enzyme According to a further aspect of the present invention a method of promoting the composting of grass cuttings comprises confining the cuttings with a composting additive comprising at least 60% by weight of a carbohydrate material together with a source or sources of nitrogen and phosphate as nutrients for composting bacteria, the additive having a C:N ratio so as to raise the overall C:N ratio of the mixture of grass cuttings and additives in a compost heap to 25 to 35:1 when applied to the grass cuttings in an appropriate amount.

The additive may comprise starch or cereal meal as the carbohydrate material and may be as described above in relation to the first aspect of the invention. The method may comprise placing a layer of material in a pit dug in the soil and adding the additive and a layer of soil and then applying alternative layers of grass, additive and soil. This may continue until the pit is full. The pit may then be covered to keep out the rain and to reduce heat losses. The layer of soil will normally contain all the bacteria required for decomposition. It also reduces loss of heat. As decomposition takes place more rapidly at elevated temperatures the conservation of heat generated in the process is important.

The amount of additive used is preferably about 1-2 handfuls (11/2-3 oz.) per three cubic feet of grass cuttings The invention is illustrated in the following Examples: Example 1 A composting additive was prepared by mixing the following ingredients.

% by weight Barley Meal 60 Ammonium sulphate 10 Superphosphate 10 Seaweed 20 Example 2 A pit 2 feet (61 cm) square and 16 inches (40 cm) deep was dug and the bottom loosened with a fork. A 9 inch (23 cm) layer of grass cuttings was put in the pit and 2 handfuls (about 3 oz) of the additive of Example 1 was sprinkled on top and mixed in. The grass was pressed down gently and a 1 inch (2 cm) layer of soil put on the top.

Two further layers of grass, additive and soil were added at weekly intervals. Three weeks later when the material in the pit has settled down a final layer of grass, additive and soil was added. The pit was covered with a board to keep out rain after the addition of each layer.

At the same time two further pits were filled, one having no additive and the other incorporating a commercially available additive containing 15% ammonium sulphate, 45% limestone, the remaining 40% being a mixture of sand and leather waste. A wire bin was also filled with grass cuttings to which the commerical additive had been added.

The efficiency of the various additives was monitored by measuring their temperatures throughout the composting process. As heat is developed in the composting process, a higher temperature will indicate a faster rate of composting.

Graph 1 shows the results of these measurements the plots being as follows: A: Pit with additive of Example 1 B: Pit with no additive C: Pit with commercial additive D: Wire bin with commercial additive.

These temperature measurements show that the pit with additive Example 1 (A) has reached the highest temperature for a longer period than either the pit with commercial additive (C) or the pit without any additive (B). All three examples in the pit reached much higher temperatures than the traditional compost heap in the wire bins, thus showing the advantage of composting in a pit.

After 4 months the contents of the three pits and wire bin were examined.

The material in the pit which was treated with additive of Example 1 was a moist dark brown, friable, sweet smelling compost. The pits containing untreated grass and grass treated with commercial additive were only partially composted and still retained the original structure of the grass. They also had a slightly putrid smell. They were unsuitable for use as garden compost.

The material in the wire bin had composted even less than the untreated grass, it was slimy green putrid mass on the inside and dry grass on the outside. Little composting had taken place.

Example 3 To test further the effect of the additive of Example 1 tests were carried out in the Laboratory. Three gallon polythene buckets were filled with grass cuttings as follows: E. The additive of Example 1 was mixed with grass in an amount of 3 oz per 3 cubic feet.

F. The commercial additive was mixed with grass at the rate of 3 oz per 3 cubic feet.

G. Untreated grass.

The effect of the different treatments were monitored over 72 hour period by temperature measurement. The observed temperatures obtained are plotted on Graph 2.

The temperature plots clearly show the effect of the Additive of Example 1, and they also show that in composting grass cuttings, commercial additives consisting of chalk and nitrogen are of little use.

WHAT WE CLAIM IS: 1. A composting additive for addition to grass cuttings to promote composting thereof

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (18)

**WARNING** start of CLMS field may overlap end of DESC **. feet of grass cuttings The invention is illustrated in the following Examples: Example 1 A composting additive was prepared by mixing the following ingredients. % by weight Barley Meal 60 Ammonium sulphate 10 Superphosphate 10 Seaweed 20 Example 2 A pit 2 feet (61 cm) square and 16 inches (40 cm) deep was dug and the bottom loosened with a fork. A 9 inch (23 cm) layer of grass cuttings was put in the pit and 2 handfuls (about 3 oz) of the additive of Example 1 was sprinkled on top and mixed in. The grass was pressed down gently and a 1 inch (2 cm) layer of soil put on the top. Two further layers of grass, additive and soil were added at weekly intervals. Three weeks later when the material in the pit has settled down a final layer of grass, additive and soil was added. The pit was covered with a board to keep out rain after the addition of each layer. At the same time two further pits were filled, one having no additive and the other incorporating a commercially available additive containing 15% ammonium sulphate, 45% limestone, the remaining 40% being a mixture of sand and leather waste. A wire bin was also filled with grass cuttings to which the commerical additive had been added. The efficiency of the various additives was monitored by measuring their temperatures throughout the composting process. As heat is developed in the composting process, a higher temperature will indicate a faster rate of composting. Graph 1 shows the results of these measurements the plots being as follows: A: Pit with additive of Example 1 B: Pit with no additive C: Pit with commercial additive D: Wire bin with commercial additive. These temperature measurements show that the pit with additive Example 1 (A) has reached the highest temperature for a longer period than either the pit with commercial additive (C) or the pit without any additive (B). All three examples in the pit reached much higher temperatures than the traditional compost heap in the wire bins, thus showing the advantage of composting in a pit. After 4 months the contents of the three pits and wire bin were examined. The material in the pit which was treated with additive of Example 1 was a moist dark brown, friable, sweet smelling compost. The pits containing untreated grass and grass treated with commercial additive were only partially composted and still retained the original structure of the grass. They also had a slightly putrid smell. They were unsuitable for use as garden compost. The material in the wire bin had composted even less than the untreated grass, it was slimy green putrid mass on the inside and dry grass on the outside. Little composting had taken place. Example 3 To test further the effect of the additive of Example 1 tests were carried out in the Laboratory. Three gallon polythene buckets were filled with grass cuttings as follows: E. The additive of Example 1 was mixed with grass in an amount of 3 oz per 3 cubic feet. F. The commercial additive was mixed with grass at the rate of 3 oz per 3 cubic feet. G. Untreated grass. The effect of the different treatments were monitored over 72 hour period by temperature measurement. The observed temperatures obtained are plotted on Graph 2. The temperature plots clearly show the effect of the Additive of Example 1, and they also show that in composting grass cuttings, commercial additives consisting of chalk and nitrogen are of little use. WHAT WE CLAIM IS:

1. A composting additive for addition to grass cuttings to promote composting thereof

comprising in excess of 60% by weight of starch and/or cereal meal as a source of carbohydrate, together with a source or sources of nitrogen and phosphate as nutrients for composting bacteria, the additive having a C:N ratio so as to bring the overall C:N ratio of the mixture of the grass cuttings and additive in a compost heap to 25 to 35:1, when applied in appropriate amounts.

2. An additive as claimed in Claim 1 wherein a nitrogen source is present in an amount in the range of 1 to 40% of the additive.

3. An additive as claimed in Claim 1 wherein a nitrogen source is present in an amount less than 10% of the additive.

4. An additive as claimed in any of the preceding Claims wherein the nitrogen source is urea, an ammonium salt, an alkali metal or alkaline earth metal nitrate, dried blood or a mixture thereof.

5. An additive as claimed in any of the preceding Claims wherein a phosphate source is present in an amount from 1 to 20% of the additive.

6. An additive as claimed in any of the preceding Claims wherein the phosphate source is a super phosphate, double or triple superphosphate, a mono- or di-ammonium phosphate or a mixture thereof.

7. An additive as claimed in any of the preceding Claims comprising a source of nitrogen and phosphate which is a mono- or diammonium phosphate.

8. An additive as claimed in any of the preceding Claims from which calcium carbonate is substantially absent.

9. An additive as claimed in any of the preceding Claims further comprising sources of bacteria and/or enzymes.

10. An additive as claimed in Claim 9 in which the sources of bacteria and enzymes are each present in an amount in the range of 0.01 to 2%.

11. A composting additive substantially as described in Example 1.

12. A method of promoting the composting of grass cuttings comprising confining the cuttings with a composting additive comprising at least 60% by weight of a carbohydrate material, together with a source or sources of nitrogen and phosphate as nutrients for composting bacteria, the additive having a C:N ratio so as to raise the overall C:N ratio of the mixture of grass cuttings and additive in a compost heap to 25 to 35:1 when applied to the grass cuttings in an appropriate amount.

13. A method as claimed in Claim 12 wherein the carbohydrate material is starch and/or cereal meal.

14. A method as claimed in Claim 13 wherein the additive is as claimed in any of Claims 1 to 11.

15. A method as claimed in any of Claims 12 to 14 which comprises placing a layer of grass cuttings in a pit dug in the soil adding the additive and a layer of soil, and then applying alternate layers of grass cuttings and additive and soil.

16. A method as claimed in Claim 15 further comprising covering the pit to reduce heat losses.

17. A method as claimed in any of Claims 12 to 16 wherein an amount of additive in the range of 1l/2 to 3 oz. is used per 3 cubic feet of grass cuttings.

18. A method of composting as claimed in Claim 12 and substantially as described in the Examples.