Table 21 Quality of Influent and Effluent for Thermophilic UASB in Vegetable Food Processing

Influent Effluent

__BOD COD BOD COD

Exp. 16,900-19,900 9,500-27,600 660-1,4001,200-2,100 Exp. 2 6,700-7,60010,500-11,800 1,400-1,600 2,000-2,300 Source: Ref. 43.

companies. Some employ a heat-shock process at 75°C for 3 hours before adding the microbes. Figure 9 shows a flow of this type adopted in Komagane City [47].

Another type of composting uses mixed culture mainly constituted by lactic acid bacteria (EM) under anaerobic condition. Figure 10 shows an example of this process adopted in a small town in Japan. Usually the addition of a relatively large amount of rice husk may be needed for the production of valuable compost.

A combination of both types of composting has also been tested. In one case, relatively fresh fish refuse was preheated at 80°C for several hours with the addition of a thermophilic bacillus, and then EM was added. In this case EM was expected to work after packaging in plastic bags. This product may be used as chicken feed.

Usually, garbage includes salt and oily materials, which makes it difficult to use as a sole source of compost. Often after drying or primary fermentation through consuming electric

Table 22 Recycling of Wastes from Beer Breweries (Kirin Beer Co. Ltd. in 1988)

Wastes

Amount (tons/year) Uses

Spent grain

359,919 Feedstuff, fertilizer, heat recovery

Refined dregs

2,618 Feedstuff, fertilizer

Excess yeast

7,168 Foodstuff, medicine

Used diatomaceous earth

17,556 Cement feedstock, soil conditioner

Wastewater sludge

35,319 Fertilizer

Paper waste

Labels

3,051 Recycled paper

Danball

2,167

Bags for raw materials

103

Used paper

400

Wood pallet

3,231 Fuel

Glass wastes

57,409 Raw material of glass

Caps

337 Raw material of steel

Aluminum cans

493 Raw material of aluminum

Steel cans

1,008 Raw material of steel

Plastic wastes

Plastic box

6,795

Plastics

553 Reductant for high furnace

Used oil

141 Fuel, recycled oil

Incineration ash

152 Cement feedstock, soil conditioner

Others

1,869

500,289

Recycling rate: 100%

Source: Ref. 46.

Figure 9 Composting process using thermotolerant microorganisms.

energy at home, restaurant, and supermarket, pretreated garbage is transported and mixed to livestock manure compost at a certain proportion, 20% for instance.

In Japan, many companies intend to produce compost using the garbage collected from commercial sectors. However, as mentioned previously, due to the difficult situation surrounding organic fertilizer, a high quality of compost is needed. Under these circumstances, a pilot study was conducted in Kitakyushu City to produce polylactic acid (PL) through glucosidation, lactic acid fermentation, butyl ester formation, hydrolysis, and polymerization [48]. The cost of

Figure 10 Composting process of garbage using EM in a small town in Japan.

3.5 $/kg PL was estimated for the plant of 100 tons of garbage/day. The harvest rate of PL is assumed to be 5% vs. garbage. If the garbage treatment cost is 30 yen/kg, then it corresponds to 600/125=4.5 $/kg PL, and it is expected to be feasible. This project is challenging, however, and may encounter other difficulties.

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