WO1997007036A1

WO1997007036A1 - A method for collection of organic waste from households and a collection bag arrangement for use in collection

Info

Publication number: WO1997007036A1
Application number: PCT/FI1996/000440
Authority: WO
Inventors: Matti Jyllinmaa
Original assignee: Matti Jyllinmaa
Priority date: 1995-08-18
Filing date: 1996-08-15
Publication date: 1997-02-27
Also published as: AU6661096A; FI953891A0; FI953891A; EP0961734A1; FI103274B1; FI103274B

Abstract

The object of the invention is a method and collection bag arrangement for the collection of organic waste from households in local waste disposal, in which the households take batches of organic waste to an intermediate collection point. The local waste disposal transportation takes batches of intermediate collection waste at regular intervals to be composted in large amounts in communal composting. Each household places accelerator amounting to 10 - 35 % of the full capacity ready in the bottom of the organic waste batch, in the same way accelerator amounting to 10 - 35 % of the full capacity is placed in the bottom of the intermediate collection mass, in which case most of the accelerator in the common composting comes from households and intermediate collection.

Description

A METHOD FOR COLLECTION OF ORGANIC WASTE FROM HOUSEHOLDS AND A COLLECTION BAG ARRANGEMENT FOR USE IN COLLECTION

The object of the invention is a method for the collection of organic waste from households in local waste disposal, in which domestic households take organic waste to intermediate collection points, from which local collection transport takes the intermediate collection batches at regular intervals to be composted in large amounts in communal composting, in which composting wood chips are used as an accelerator. The invention also concerns a suitable collection bag arrangement for use in the collection of household organic waste.

The separate collection of organic waste is part of sorting at the point of creation, by means of which waste disposal can be carried out in a more environmentally-friendly manner, by recycling a large part of waste. Organic waste is utilized in domestic households on a small scale for their own compost, but this is not a suitable solution in many cases. Organic waste is collected in large towns in Finland. The most common collection container is a 240-litre plastic container, which is adapted to be packed into the emptying system of a collection truck. An essential problem with the present collection technique is the unpleasant smell, which is because liquids separate at the bottom of the container and organic waste begins to decompose due to the lack of oxygen. In winter, the organic waste freezes in the container. During transportation, the remainder of the oxygen vanishes and it is difficult to make such a mass decompose and compost. The present technology is expensive, because containers break in winter due to freezing. In summer, the smell is practically unbearable. Due to the problem of hygiene, the containers must often be washed, which cause considerable additional costs. Especially when being transported in a compressing waste disposal truck, the air in the waste is finally pressed out and decomposition, i.e. an anaerobic process, is reinforced. The composting of such a mass is extremely arduous and expensive. Up to 60 - 70 % of wood chips must be mixed into the mass and it must be mixed several times for composting to begin. Large 240 litre paper sacks are also used now in local collection points, the sacks themselves being designed to decompose rapidly. This large collection sack does not, however, remove the above problems.

Waste bags made of paper, suitable for composting, and fitting the inner size of the container, are known in organic waste collection, e.g. Finnish patents 89889 and 47172. A paper waste container is known from German patent application DE 4304 715 and has a porous bottom mass, a cellulose wool mat. So-called super-absorbent granules are also proposed for use in this. The bottom mass in its various forms is intended to absorb the liquids flowing from the waste and to dry them for later composting. These substances are expensive and they do not act as compost accelerators.

The intention of this invention is to make the collection of organic waste, from household to large batch composting, more hygienic, effortless, and easy to use and to remove the aforementioned defects in the collection of organic waste. The characteristic features of the method according to the invention are described in the accompanying Patent Claim 1. The characteristic features of a collection bag arrangement easing the implementation of the method are described in Patent Claim 4.

Because an accelerator is required in any case when composting organic waste, it is practical to add it already in the household, when considerable benefits are obtained from it during the transportation chain, besides the fact that the handling of organic waste in the household is considerably cleaner and with less odour. In the same way, the aforementioned compost accelerator is added to the bottom of the mass of the organic waste at the intermediate collection points, in which case it is no longer necessary to add so much accelerator as previously to large batches being composted communally. By adding accelerator, most advantageously crushed and dried willow chips with peat, to the compost, composting begins already in the household without odour detriments. After this, when the batches of organic waste are emptied into large collection containers or other intermediate collection containers in which there is in the bottom willow chips and advantageously also peat as accelerator according to the method, transportation can take place hygienically and nearly without odour. By this means, it is thus possible to avoid the health risks caused by present unhygienic transportation and the freezing of the mass in winter. Even if the mass freezes, it will, however, easily crush and melt.

Because the composting of the organic waste begins already in the household, the heat arising from this benefits the composting in the intermediate stage in large sacks. It should be emphasized, that, to work, the method described definitely requires a high-quality compost accelerator. The accelerators used until now, such as forest litter, bark mass, and ordinary woodchips (without drying and crushing) , as well as pure peat are not sufficiently good to ensure the success of the entire organic waste transportation chain. On the other hand, crushed and dried, especially hot-air dried willow chips, have proven particularly efficient as compost accelerator. The absorptive capacity of this kind of willow chips is considerably greater than many other species of wood. The wood of willow has a soft cellular structure, which itself composts rapidly. In addition, there is a high proportion of bark, which improves the quality of the humus obtained.

Using a layer of peat beneath the willow chip layer is advantageous, as this improves the overall operation. Peat binds a great deal of water, it kills odours, and is an antiseptic substance. The layer of willow chips at the bottom of the bag forms an air-grate, which effectively distributes air to the organic waste. Willow chips are most advantageously obtained from willow trees in special will plantations, but other willow (Salix) species can also be used. The production of willow can be organized effectively even in northern areas like Finland. The willow chips used must in any event be dried very well. The moisture content should be less than 20 % preferably 10 - 15 %. Crushing the willow chips decisively improves their absorbency.

The accelerator according to the invention is homogenously mixed through the mass to be composted. When households put accelerator into every batch of organic waste, the organic waste and the accelerator are homogenously mixed already at the intermediate collection stage. After this too, the accelerator at the bottom of the large collection sacks in common composting is distributed automatically evenly throughout the entire mass.

In what follows, the invention is illustrated by reference to the accompanying figures, which show treatment arrangements for organic waste in domestic households and at intermediate collection points.

Figure 1 shows a waste trolley for use in domestic households, in which there is an organic waste collection bag. Figure 2 shows an organic waste collection bag with accelerator. Figure 3 shows large sacks in an intermediate collection point. Figure 4 shows collection bags as a transportation package. Figure 5 shows a local collection chain for organic waste.

Point of creation sorting in a domestic household means the separate collection of different types of waste, which demands suitable collection implements. Figure 1 shows one waste trolley suitable for point of creation sorting, which is put into, for example, a kitchen cabinet, from which it can be pulled out. There is a frame 11 in waste trolley 1, which holds organic waste bags 2 and standard bags 3.1, 3.2, and 3.3 for other types of waste. These types may be, e.g. burnable dry waste, glass/metal, and problem wastes. These can now be easily carried out to the waste collection point in their own bags for further sorting. Waste paper has its own storage devices (not shown) . The bags in frame 11 of the waste trolley in Figure 1 are at the same height at the top part, in which case smaller bags are raised from the bottom by the requisite amount.

The organic waste collection bags 2 are in standard sizes (8, 30, and 240 litres) . In domestic households it is most advantageous to use 8-litre paper bags, which are supplied together with the accelerator as a transportation package 2' according to Figure 4. The upper part of the package is wrapped around the refill 5, 6, in which case four such pieces will fit into a single 8-litre bag, which arrangement is used as a retail package. The user opens the transportation package 2' and puts it into the frame of the aforementioned waste trolley or a similar receptacle. It is possible to consider using, e.g. compostable plastic bags made from starch instead of the paper bags, but in that case the accelerator layers on the bottom are especially important.

There may be handles 13 in the organic waste collection bag according to Figure 2, which make it easier to handle. There is a prepared refill, containing layers of willow chips and peat 5 and 6, in the bottom of bag 2. Of these, the willow chip layer 5 is uppermost. The combined amount of the accelerator is 15 - 40 %, most advantageously 30 - 35 % of the amount of the contents.

It has been noted in practice, that the sharp folds in the corner's 4 of the paper bag allow air to bottom, when the circulation of the air is sufficiently effective for composting. Most advantageously willow chips are 2/3 (in any event 30 - 100 %) of the accelerator and peat 1/3 (20 - 40 %) . The moisture content of the willow chips is 20 % at most, which can only be achieved by mechanical drying.

Willow can be produced efficiently. Known devices can be used for chipping, but if pieces remain whole, they are crushed separately. Alternatively, a special crushing chipper can be used. The pieces are sieved with a 30 - 40 mm sieve and the finished chips are dried with warm-air drier.

Household collection bags can be placed in an intermediate collection container, but the bag must definitely be thrown there open, so that composting does not stop. After emptying, dry bags can also be put with burnable dry waste, so that there should be a collection receptacle for this next to the organic waste collection container.

As an alternative, in the solution in Figure 4 the compost accelerator is sold ready- layered as a separate refill. Thin paper or net is used as the wrapping of the refill .

Food and other organic waste gradually fills the collection bag 2, when it forms an organic waste batch ready to be taken to the intermediate collection. Due to the willow chip and peat layers 5 and 6, composting starts to well that the bag can be left open, when moisture evaporates and the upper part of the bag and the possible handles remains sufficiently strong to be moved. A possible cover will condense moisture, which weakens the bag. Here is the precise difference from previous practice, in that such collection batches are not closed on top, but are allowed to remain open, whereas until now domestic household organic waste collection devices have normally been closed. In that case, composting does not even start, due to a lack of oxygen, instead an anaerobic process has begun already at the household collection point. The composting of a batch of organic waste produces heat, which is particularly beneficial in winter, when it is considerably easier to maintain composting in the intermediate collection point. In any event, even if the mass does freeze, composting can be started significantly more easily than before, because the drying agent is ready homogenously throughout the compost.

In the intermediate collection point, Figure 3, large collection sacks 7 are used, which are placed in a suitable frame or container 10. A willow chip layer 8 and a peat layer 9 are placed on the bottom of this as described above. In the inner walls of the large collection sack 7, it is advantageous to use biologically degradable, e.g. starch-based, water- resistance plastic membrane, which particularly improves the wet strength of the sack. The air in the container 10 and the accelerator layer provides initially a sufficient quantity of air for composting. The overlap 7.1 of the large collection sack 7 may create a small air gap when the cover 12 is closed. In addition, when the container is used, new oxygen-rich air enters the container 10 each time the cover 12 is opened. When household organic waste collection bags are tipped into this large collection sack 7, compost accelerator always comes with the organic waste batch and mixes effectively with the intermediate collection batch.

The use of a small collection bag with accelerator also brings advantages in connection with single-building composting, on account of its odourlessness, among other things. Suitable bacteria for composting begin to grow already in the kitchen collection bag, when the amount of the waste diminishes. Willow chips and peat act as sources of carbon in the composting process.

The local collection of organic waste in carried out according to the invention best in the manner shown in Figure 5. Each household and other producer of organic waste, for example a restaurant and shop, collects organic waste in a composting bag 2, in each of which there is the aforementioned efficient compost accelerator. Once it is full, each bag 2 is taken to the intermediate collection container 10, in which there is a large collection sack 7. On the bottom of this too, layers of efficient compost accelerator, willow chips and peat 8 and 9 are placed. Intermediate collection batches from different intermediate collection points (containers 10) are collected with a compressing waste truck 15 and are transported to a composting plant. There the entire load is once again mixed and crushed using a suitable mixing device 16, from which the mass is taken to, e.g. a stockpile 17 for composting. It is naturally possible to use other composting solutions, such as composting drums or reactors .

Willow chips have odour-binding qualities that are nearly as good as peat. If a partly filled organic waste container stands for a longer time and begins to smell, willow chips should be added, particularly to the edges of the mass, because bad odours come from deeper in the mass along the edges.

Claims

Patent Claims

1. A method for the collection of organic waste from households in local waste disposal, in which the households take batches of organic waste to an intermediate collection point, from which the local waste disposal transportation takes batches of intermediate collection waste at regular intervals to be composted in large amounts in communal composting, in which composting wood chips are used as an accelerator, characterized in that each household places accelerator amounting to 10 - 35 % of the full capacity ready in the bottom of the organic waste batch, and at each intermediate collection point in the same way 10 - 35 % of accelerator is placed in the bottom of the intermediate collection batches, in which case most of the accelerator in the common composting comes from households and intermediate collection, and that at least some of the wood chips used are crushed and dried willow chips, with a moisture content of at most 20 %.

2. A method according to Patent Claim 1, characterized in that the intermediate collection takes place in easily compostable large, 100 - 300 litre paper sacks (7) and with such good air circulation that composting can continue.

3. A method according to Patent Claims 1 or 2, characterized in that beneath the wood chips, 40 - 60 % of the amount of the chips is principally dry sphagnum peat.

4. An arrangement intended for the collection of household organic waste, in a bag (2) is intended to be placed in a container/frame (11) to collect organic waste, and to be used to transport the organic waste to a collection point once the bag is full, and in which porous accelerator is used in the bottom of the bag, characterized in that 30 - 100 % of the aforesaid accelerator is crushed and dried willow chips with a moisture content of at most 20 %, most advantageously 10 - 15 % placed in the bottom of the bag, and that the total proportion of the accelerator is 15 - 40 %, most advantageously 30 - 35 %, of the total capacity of the bag.

5. An arrangement according to Patent Claim 4, characterized in that there is 20 - 40 % dry sphagnum peat in the accelerator and it is placed as a separate layer beneath the wood chips.

6. An arrangement according to Patent Claims 4 or 5, characterized in that the container is open at the top and the bag is placed in such a way that moisture can evaporate freely from the mouth of the bag.

7. An arrangement according to Patent Claims 4 or 5, characterized in that the collection bag (2) with the accelerator layer (5, 6) forms a ready-made collection device, which is packed in the transportation stage by wrapping the empty part (13) of each bag round the accelerator layer.

8. An arrangement according to Patent Claims 4 or

5, characterized in that the accelerator layers (5, 6) form a ready-made refill, to be placed in the collection bag.

9. An arrangement according to one of Patent Claims 4 - 8, characterized in that the bag (2) is of paper.

10. An arrangement according to one of Patent Claims 4 - 8, characterized in that the bag (2) is of compostable plastic.