Utilization of biological waste

TECHNOLOGY In the ATON-HT company it has been worked out an unique microwave technology to effectively remove organic  impurities like veterinary wastes, post slaughtered wastes, meat wastes, food wastes, poultry-farming wastes, sewage wastes, etc.

 

MICROWAVES IN BIOLOGICAL WASTE UTILIZATION PROCESSES - CARBONISATION OF WASTE

 

ATON-500 BW – utilization of organic discards. 

 

Fig. 1. ATON 500 BW reactor.

 

 

Process has two stages: in the first stage material is being dried and heated to a temperature of 100 - 150ºC, then it is inserted in microwave process chamber. Material is being heated to a temperature of 600 - 650ºC there, in the consequence pyrolysis processes appear and remain small quantities of constant fractions which consist of carbon and mineral substances. At the same time released gases are after-burnt in the microwave reactor MOS which is made to effectively remove tail gases. Energy from gases that lower reactor is used in process of preliminary material heating.


This process is illustrated by block diagram.

 Fig. 2. ATON 500 BW block diagram.

 

 

Technical parameters of mobile device ATON 500 BW:

 

SUPPLY	3 x 400V (50Hz)
MAX. POWER INPUT	100kW
MICROWAVES INSTALL POWER	30kW (f=2450MHz)
PRODUCTIVITY	200-500kg/h (depends on water content in charge material)
COOLING	aquatic in isolated system with the possibility of energy recovery
OVERALL DIMENSIONS	20 feet container 6x2,4x2,5 m
SERVICE	One-man, automatic control

 

 

 

Fig. 3. Picture of ATON 500 BW prototype reactor.

The most important qualities of the offered technology:

 

• Process is characterized by low energy consumption.
• Pyrolysis gases released in microwave reactor are being after-burnt in microwave cleaner. Energy received in this process is used for additional heating of oil which heats cleaners’ wall.
• Gases that are emitted in installation don’t contain any harmful substances, it isn’t also a source of unpleasant odors – thanks to the afterburner, where complete after-burning of organic substances takes place.
• Installation of this technological conception could be assembled on containers and transported into places where the wastes appear. Thanks to it it’s possible to work carbonization process of waste in the place where it emerges. 
• The process doesn’t produce any wastes because carbonate forms there (carbon + mineral compounds), neutral for people and environment

 

Investigated fields of usage:

Poultry-farming wastes – in poultry-farming industry appear different kinds of post productive wastes, which are divided into three groups:

 

• Inedible products of slaughter (in poultry slaughterhouse)
  • soft: blood, guts, crops, gullets, skin cuttings, deposits from sewage treatment,
  • hard: feathers, heads, paws;
• Unfertilised eggs, egg shells, nestlings deceased and crippled (in hatcheries);
• Waste eggs (egg-producing industrial plants).

 

Inedible products of slaughter makes up 90% all produced wastes, about 9% are wastes from incubating and egg-producing industrial works, 1% are wastes from mechanical cleaning of sewage treatment.
Main direction of productive waste management is their processing into feed meal (about 70% of waste materials). Meat-and-bone meal made from these wastes are protein-rich. Only 3% of these wastes are removed to storage yards.

Most of wastes, that are potential secondary materials, arises during post slaughtered treatment:

 

• Blood, that contains 18-20% of dry substance, including 17-19% of proteins
• eathers contains 70-80% of proteins. Basic protein of feathers is keratyn, that has  scarce biological value. That is why feathers are processed by thermal hydrolysis method. Received concentrate contains available proteins. Feathers from rummaging poultry and water poultry (especially geese’s) are used in bedding manufacturing.

 

 

Dead poultry management is still very difficult problem. To avoid of digging it in random places and remove it to storage yards (what is inadmissible), dead poultry from hatchery is partly used in meal manufacturing in the utilization plants.
As a result of poultry-farming wastes utilization processes form products, that could be used in agriculture or in natural purposes. Content of macro components and metals in investigated products of utilization are in established standards. It could be a rich source of nutrient substances for plants. Surely it isn’t harmful for environment.
 

 

 

 

Fig. 4. Poultry-farming samples before and after process of utilization in ATON 500 BW.

After the utilization about 90% of mass is reduced (in relation to fresh material mass) In comparison with fresh material, chemical constitution has changed in many cases after the carbonization process. In this process content of organic carbon and nitrogen was reduced even several times. In such processes it is a normal phenomenon, because this chemical element escapes in a gas form. But from the point of view of plants nutrition these are small quantities. Other chemical elements appear in quantities approached to fresh material’s and they could be valuable sources of nutrients for plants. After the carbonization process content of heavy metals like iron, zinc, nickel stays on level closed to their content in fresh materials. Its absolutely safe from the point of view of natural usage. Content of lead and cadmium was radically reduced and after the carbonization these metals are minute quantities in investigated materials. The same thing happens with chromium and arsenic.
Preliminary comparison of manganese and copper content in fresh materials with the materials after carbonization shows their fortifying with these metals. In both cases content growth is even twice. However still quantities in all materials don’t obstacle in their natural usage after the carbonization. Very important is to add sawdust to blood before the carbonization process. It corrects chemical constitution of blood as a initial material. It increases content of carbon and basic compounds necessary for plants  whereas it reduces content of heavy metals, probably because of biological sorption. To sum up chemical composition of organic materials put to the carbonization process allows to use it in agriculture.

 

Sewage wastes – form in sewage-treatment plants as a specific waste of sewage-treatment processes. Chemical composition of sewage wastes is variable and depends on many factors, among others type of sewage and processes of their treatment. Participation of industrial sewage in municipal sewage and it’s type may influence decisively on post sewage wastes quality. Quantity of organic substance in sewage wastes ranges from 22,5 to 60,8% in dry matter, with average 45% content of water. Besides from reach organic matter sewage wastes contain many compounds and chemical elements needed to growth and expansion of plants and microorganisms. Limiting factor of using wastes in soil fertilization and reclamation is high content of lead and zinc, and the presence of organisms that are dangerous for people. Sewage wastes have physical and chemicals attributes closed to humificated peat. Dump wastes should be dehydrated. There are few methods of dehydration:  sedimentation density, sludge drying beds (20% of dry matter content, obtained in several weeks), reedy drying beds (35-40%), mechanical hydration – spin dryer or tape press (15-20%), chamber press, deposit dryer.

 

 

 

 

Comparing dry matter with utilization product it was obtained 95% mass reduction.
Heating value of fresh sewage sludge is in the range of 14-12 MJ/kg depending on samples; humidity.Fresh sample contains almost 50% of carbon, over 5% of nitrogen, considerable quantities of phosphorus, but very little potassium and salt. Magnesium doesn’t exceed 1%. Content of sulfur is on average level, relations H:C, O:C and N:C are correct.
In samples, after the carbonization content of macrocomponents is in established norm, in regard of usage in agriculture and application of investigated substances.