Agricultural Wastes最新文献

This paper describes the process of pickling slaughterhouse by-products with inorganic acids in order to prevent spoilage and improve processing economics. The addition of sulfuric acid (3% by weight of the material to be pickled) was found to prevent the rapid onset of putrefactive changes and did not adversely affect crude protein composition. The pickled products have potential use as a source of protein in terrestrial animal feeds. Due to their low residual acidity and low water solubility, the pickled products also have potential use in aquatic animal diets.

Reductions in fossil fuel and waste disposal costs could be achieved by apple processors through in-plant combustion of apple pomace. Life Cycle Costing techniques were employed to compare the average annual costs (prior to tax calculations) for investment in a handling/boiler system at 1983 prices. Operating conditions were representative of a small and large firm (producing 27 200 and 90 700 kg of pomace per day, respectively), which would combust all of the pomace generated. A loan of 14% annual interest with a 5-year payback period was assumed for the total fixed cost of each of three handling/boiler systems. The investment would be cost-effective for a small processor incurring 80% of disposal costs and for a large processor incurring 20% of disposal costs, with a fossil fuel price of $7·14 per gigajoule. The break-even point is most sensitive to waste flow rate, disposal cost and fossil fuel price.

Biological fermentation of whole fish, viscera and heads using Lactobacillus plantarum was evaluated and the minimum lactose necessary for a successful fermentation under pilot conditions was found to be 5%. Preheating the fish before fermentation decreased the amount of soluble nitrogen substances both before and after fermentation. The relationships between lactic acid bacteria growth, yeast and mold growth and pH indicated that it may be necessary to add an antimycotic agent to achieve and maintain sufficiently low pH values for successful fermentation and storage. Fermentation temperatures of 25 and 35°C and inoculum size of 10³ organisms g⁻¹ of fish produced successful fermentations.

Munj (Succharum munja) plants, available in abundance in India, can be used to make rope. A stripper for the separation of the fibrous leaves from the stalks and a beater to make the leaves suitable for rope preparation were developed. A locally available rope making machine was evaluated and the economics of rope making assessed. The technology developed has good potential for adoption at the village level with attractive returns.

The effect of salts accumulation—a result of effluent recycling and chloride salts addition—in a simulated anaerobic swine lagoon has been studied. Three laboratory scale reactors were used to simulate actual lagoon conditions. The cations Na, K, Ca and Mg were added as chloride salts, and via the sun dried lagoon effluent, to two of the reactors at the concentrations and ratios found in the sun dried effluent. The results indicated that salts accumulations caused similar effects on biological activity, according to a general toxicity model suggested in earlier work. Salts accumulation was expressed as electrical conductivity (EC). Optimum biological activity was obtained at EC values from 5 to 8 mS for the chloride salts and from 25 to 35 mS for the recycled effluent. Effluent recycling thus caused similar effects on biological activity at much higher salts concentrations than the chloride salts, possibly due to cation antagonisms. A direct conclusion is that effluent recycling is feasible in anaerobic swine lagoons and to a much higher degree than was previously thought. From the practical point of view, effluent recycling will minimize lagoon effluent disposal problems and the treatment cost of the wastes produced in swine farms.

A comparison was made between three goat genotypes (100%, 75% and 50% Katjang), 4% NaOH treated and untreated rice straws fed ad libitum, and 4% NaOH treated and untreated dehydrated palm oil sludge (POS) fed at 20 g per kilogram liveweight (LW) per animal per day. A 1 kg supplement of Leucaena leucocephala was fed daily to each animal.

Average total dry matter (DM) intake and LW gain (LWG) was 48·1 g per kilogram liveweight per day and 33·4 g per day, respectively. Alkali treatment increased intake of straw (P< 0·001) and LWG (P < 0·05). Mean DM intake of straw was low, 3·8 g per kilogram liveweight per day. Treated-POS promoted lower gains (P < 0·05) than untreated-POS diets.

Mean apparent digestibility of DM, crude protein, crude fat and neutral detergent fibre was 61·8%, 64·4%, 82·2% and 61·2%, respectively. For most constituents, there were no significant differences in digestibility between alkali treated and untreated diets.

The 100% Katjang gave lower gains (P < 0·01) than crossbred genotypes. There were no signs of mimosine toxicity; mimosine in the Leucaena was 2·96% of DM.