Massimo Cecchini1*, Danilo Monarca1, Andrea Colantoni1, Fulvio Cavariani2,

Loredana Bedini2, Marcello De Rossi2, Mauro Pagano3, Marco Fedrizzi3,

Mirko Guerrieri1

Study of a Device for Reducing the Dust Concentration During

Mechanized Harvesting of Hazelnuts

1University of Tuscia – Department DAFNE, Viterbo, Italy

2Viterbo Local Health Unit, Laboratory of Industrial Hygiene, Civita Castellana VT, Italy

3Agricultural Research Council, Agricultural Engineering Research Unit, Monterotondo RM, Italy

Aim One of the main risk factors for workers derived by

mechanized harvesting of hazelnuts is the exposure to respirable dust (Biondi et al., 1992; Monarca et al., 2005).

The aim of this paper is to test a device to be applied directly on the harvesters, that manages to give the soil suitable moisture, reducing the dust development.

Aim The problem becomes significant in those areas where

the cultivation of hazelnut has spread. In some of these sites, harvesting was possible when the rainy season started, especially for hazel trees close to residential areas.

Even in 2011 (when tests were carried out), some local mayors have issued specific orders to shift the harvesting to the first rains arrival. The harvesting period (August and September 2011)was characterized by particularlyhigh levels of drought.

Rain (in mm) in the municipalities delimiting the hazelnut area of cultivation

Month

Stations

Bassano R. Corchiano VetrallaSoriano C. (Station I)

Soriano C. (Station II)

Viterbo

Year 2011

Monthly average

2004-2010

Year 2011

Monthly average

2004-2010

Year 2011

Monthly average

2004-2010

Year 2011

Monthly average

2004-2010

Year 2011

Monthly average

2004-2010

Year 2011

Monthly average

2004-2010

June 43.20 45.01 61.40 43.50 26.60 55.34 57.20 53.09 42.40 50.00 51.10 45.80

July 106.60 23.66 100.80 18.46 102.00 13.54 138.60 19.51 125.20 23.03 65.30 12.85

August 0.40 26.17 0.80 20.14 0.20 22.93 1.70 35.84 0.80 39.03 2.40 28.25

September 29.60 76.17 40.20 82.43 50.80 73.36 62.40 93.03 22.60 85.74 72.70 69.12

(ARSIAL, 2011)

The problem During the past years the problem was addressed

through efforts that can be summarized as follows (Cecchini et al., 2005; Cecchini et al., 2010; Monarca et al., 2005; Monarca et al., 2008; Monarca et al., 2009; Monarca et al., 2010; Monarca et al., 2011): use of machines with cyclones; use of pick up machines instead of vacuum machines; grass covered ground instead of tilled soil; discharges of dust directed towards the ground rather than in the

air. The mentioned solutions could not overcome the

situation which still recurs every year, especially during particularly dry summers.

Material and Methods

The operations taken into account by the present study were tested on a self-propelled harvester (model Cimina 380 S) manufactured by the company FACMA S.r.l.. If compared with other machines produced by FACMA, Cimina 380 is characterized by a greater suction flow and the absence of cyclones used to reduce the dust

Material and Methods The device is based on the use of sprayers,

already experienced in agriculture for irrigation and pesticide treatments. It uses the principle of pneumatic nebulisation at low volume.

The device is composed of the following elements: tank diaphragm pump nozzles and nozzle holders spraying bar valves and pipes for transporting water.

Material and Methods

• The tank has been positioned within the carriage for the storage of the product. It is made of metal sheet, has a capacity of about 290 liters and is equipped with a discharge point located about 10 cm from the bottom. This is to avoid that any sedimented material can pass into the pipe connected to the pump

Material and Methods

• The nozzles (four Lurmark 04 M110 and four Lurmark 02 M110 were tested) are positioned on a bar mounted on the harvesting head.

• The hydraulic circuit is made by an electric pump (SHURflo 2088-313-544)

Material and Methods

• The dust control is also achieved through appropriate devices, positioned along the exhaust pipes of the powder: water, delivered through nozzles to low volume sprayers, intercepts the flow of dust, leaves and twigs, before they're released outside

Material and Methods A first evaluation of the effectiveness of

the proposed device was performed by measuring, with appropriate instrumentation, the concentration of dust which affects the operator and persists in the environment.

Six environmental samplings and six personal samplings on driver were performed, using portable analyzers for direct reading (DustTrak Aerosol Monitor TSI model 8520 for the environment and SidePak Aerosol Monitor TSI model AM 510 for worker). The instruments were equipped with a Door-Oliver selector for respirable fraction.

Results Environmental sampling

(DustTrak Aerosol Monitor) Personal sampling

(SidePak Aerosol Monitor) Device performance

Tim

e Test

nr. Description of test min max avg min max avg Flow

Volume per hectare

(mg/m3) (mg/m3) (mg/m3) (mg/m3) (mg/m3) (mg/m3) (l/min) (l/ha)

1 Hazelnut harvesting in standard

conditions (dry soil) 0.215 7.41 0.695 0.026 2.852 0.308 - -

2 Hazelnut harvesting with 3 rear

nozzle Lurmark 02 F110 on 0.063 5.071 0.167 0.028 6.328 0.370 3.00 143

3 Hazelnut harvesting with 3 rear

nozzle Lurmark 04 F110 on 0.164 0.219 0.201 0.035 2.573 0.185 5.70 243

4 Hazelnut harvesting with 4 front

nozzle Lurmark 02 F110 on 0.082 0.159 0.151 0.033 1.955 0.128 4.00 190

mor

ning

5 Hazelnut harvesting after 30 min by

moistening the soil with hand sprayer 0.798 0.940 0.878 0.030 5.273 0.316 5.45 588

6 Hazelnut harvesting with 4 front

nozzle Lurmark 04 F110 on 0.358 0.438 0.400 0.029 18.724 1.814 7.50 386

afte

rnoo

n

7 Hazelnut harvesting after 15 min by

moistening the soil with hand sprayer 0.201 4.09 0.773 0.025 4.312 0.256 5.45 588

Conclusions The number of tests does not allow a statistical

treatment of data. Because of the very high number of variables involved (e.g. air speed and direction, soil moisture, planting distance and so on), the implementation of assessment protocols - that can provide statistically acceptable regressions for instance between hydraulic flow/number of nozzles mounted on the machine and dust concentration - doesn't seem to be reasonable.

However, the first tests show a decrease of dust concentration with sprinklers mounted in front of harvesting apparatus of the machine (the area where dust is generated).

Conclusions The use of water as a method for reducing the

concentration of dust during the harvesting of nuts seems an achievable goal. The use of the pump which sends the water to the nozzles has enabled progress in reducing the dust concentration. It can be improved as a result of tuning of the system.

The water consumption can be decreased through the use of a pump that generates a greater pressure and by mean of nozzles which deliver a lower flow rate, but with drops properly sized in order to achieve dust reduction.

Conclusions With regard to the front of the machine, the ends of the

bar will have to be equipped with asymmetrical jet nozzles, so that we can spray from the harvesting head to the side part of the land. This area is generally cleared of hazelnuts because they have been already aligned to the center of the row through a previous agricultural operation. Indeed a good percentage of dust raised in the site due to friction operated by rotating brushes.

The results of this study can help the research and development of new prototypes, in order to make significant reduction in dust emission.