Biogas from Tofu's Waste Liquid

Tofu's Waste Liquid

Tofu is one of the traditional foods are usually consumed each day by the people of Indonesia. Know the production process forming 2 types of waste, solid waste and liquid waste. In general, solid waste used as animal feed, while the liquid waste dumped directly into the environment. Wastewater plant knows it has a high content of organic compounds. Without handling the process well, sewage know cause negative impacts such as water pollution, sources of disease, odors, increase the growth of mosquitoes, and reduce the aesthetic environment.
Many manufacturers know the scale of households in Indonesia have no wastewater treatment processes. Unwillingness to know the factory owners to treat liquid waste due to the complex and inefficient sewage treatment process, plus it produces value-added. In fact, a tofu factory effluent has high content of organic compounds that have the potential to produce biogas through an-aerobic process. In general, biogas contains 50-80% methane, CO2, H2S and a little water, which could serve as a substitute for kerosene or LPG. By converting liquid waste into biogas plant knows, the factory owner knows not only contribute in protecting the environment but also increase revenues by reducing fuel consumption in the process of making out.


Raw materials of liquid waste into biogas know

Most of the wastewater produced by industrial manufacturing know is a viscous liquid which separated from the clot out called whey. This fluid contains high levels of protein and are readily biodegradable. Wastewater is often discharged directly without prior processing resulting stench and pollute rivers. Other sources of liquid wastes from washing soybeans, washing process equipment, washing floors and cooking as well as the solution of soaked soybeans. The amount of wastewater generated by industry know maker is about 15-20 l / kg of raw materials of soybean, whereas approximately pencemarnya materials for TSS of 30 kg / kg raw soybeans, BOD 65 g / kg of raw materials soybean and cod 130 g / kg of raw materials soybean (EMDI & BAPEDAL, 1994).

In tempeh industry, most of the liquid waste generated from the location of cooking soy, soy laundering, process equipment and floors. Character wastewater produced in the form of organic material suspended solids (skin, mucous membranes and other organic material).

Industrial manufacture of tofu and tempeh to be careful in the hygiene program and maintenance of plant equipment either directly because it can reduce the content of protein and organic material carried in the wastewater.


Application of the 3R Waste Treatment Process Know

Reduce:

1. Waste Management In Physics
In general, prior to further processing of wastewater, it is desired that the suspended materials are large and easy to settle or materials that float is set aside in advance. Screening is an efficient and inexpensive way to set aside a large suspended material. Materials are easily suspended sediment can be easily set aside by the deposition process. The main design parameters for the deposition process is the speed of the particles settle and hydraulic detention time in settling tanks.

2. The Chemical Waste Treatment
Chemical waste water treatment is usually performed to remove particles that are not easy to settle (colloidal), heavy metals, phosphorus compounds, and toxic organic substances; by putting certain chemicals that are needed. Provision for such materials in principle take place through changes in the properties of these materials, that is from can not be easily deposited deposited (flocculation-coagulation), either with or without oxidation-reduction reaction, and also takes place as a result of oxidation reactions.
3. In Biological Waste Treatment
All biodegradable waste water can be treated biologically. As a secondary processing, processing nbiologi viewed as processing the most inexpensive and efficient. In the past few decades has developed various methods of biological treatment with any modifications.
Basically, a biological treatment reactors can be divided into two types, namely:

• Suspended growth reactor ; 
• Attached growth reactors 

In the suspended growth reactor, the microorganisms grow and thrive in a state of suspension. Activated sludge process is widely known place in the reactor of this type. Activated sludge process continues to evolve with various modifications, such as: oxidation ditch and a contact-stabilization. Compared with conventional activated sludge process, oxidation ditch has several advantages, namely BOD reduction efficiency can reach 85% -90% (compared to 80% -85%) and less sludge produced. In addition to higher efficiency (90% -95%), contact stabilization has the advantage of others, namely the total hydraulic detention time is shorter (4-6 hours). Contact-stabilization process can also be set aside BOD suspended through the process of absorption in the tank so that contact is not required allowance for BOD suspended by preliminary processing.

Reuse:

Waste generated from the manufacturing process can be used as an alternative idea fodder. This was done because the dregs know there are more nutritious. Namely, protein (23.55 percent), fat (5.54 percent), carbohydrates (26.92 percent), ash (17.03 percent), crude fiber (16.53 percent), and water (10.43 percent ). One reason, in addition to reducing environmental pollution, especially water.  

Recycle:

Former cooking and soaking solution can be recycled back and used as the initial leaching water soybean. Careful treatment is also done on a clot that formed carried out as efficiently as possible to prevent water-borne protein curd. 

3. material

Reshuffle (degradation) of organic liquid waste will produce methane gas, carbon dioxide and other gases and water. The reshuffle could take place in aerobic and anaerobic. In aerobic processes liquid waste contact with air, otherwise the liquid waste anaerobic conditions are not in contact with the outside air.

Usually farm waste biogas created from the excrement of livestock and feedlot cattle, but in principle, biogas can also be made from liquid waste. Biogas is actually a methane (CH4). Methane gas is odorless, colorless and highly flammable. In general in nature do not form as a pure gas but other mixtures of methane gas by 65%, 30% carbon dioxide, hydrogen disulfide and 1% other gases in very small quantities. Biogas, 1,000 ft3 (28.32 m3) has a value equal to 6.4 burning gallons (1 U.S. gallon = 3.785 liters) butane, or 5.2 gallons gasoline (petrol) or 4.6 gallons of diesel oil. To cook in the household with 4-5 members of the family quite 150 ft3 per day.

Decomposition process liquid wastes into biogas will take approximately 8-10 days. Decomposition process involving several bacterial and fungal microorganisms either, among others:

a. cellulolytic bacteria

Cellulolytic bacteria digest cellulose into sugar duty. The resulting final product will experience the difference depends on the process used. In the process of aerobic decomposition of sewage will produce carbon dioxide, water and heat, while in the process of anaerobic end products in the form of carbon dioxide, ethanol and heat.

b. Acid-forming bacteria

Charge of acid-forming bacteria to form organic acids such as acids butyrate, propionate, lactate, acetate and alcohol from the substance-substance complex polymers such as proteins, fats and carbohydrates. This process requires an anaerobic atmosphere. Stage of this revamp is the first stage in the formation of biogas, or often called asidogenics stage.

c. Methane-forming bacteria

This class of bacteria actively remodel acetate into methane and carbon dioxide. This stage is called metanogenics requiring anaerobic atmosphere, the pH should not be too acidic because it can kill bacteria metanogenics.  

4. cost:

* Direct Costs

- Raw material costs: Soybeans, microorganisms or bacteria support the processing

* Costs do not Jump: wages, equipment maintenance.

5. energy

The use of liquid waste know as a raw material for biogas use the materials that can be updated as the use of bacteria or microorganisms in the processing process. So that the processing can be mengemat energy.

5. New products

Products produced from processing waste out of biogas liquid is. Bio gas is very beneficial for household appliance / daily necessities, such as fuel stove (for cooking), lighting, heating / gasolec, the supply of fuel for diesel engines, for welding (cutting iron), and others. While the benefits for the environment is a process of fermentation by anaerobic bacteria (bacteria methane) reduction of environmental pollution levels with parameters of BOD and COD will be reduced up to 98% and waste water meets quality standards for the government's so worth the waste into a river. Bio gas also indirectly benefit in energy savings that come from nature, especially natural resources are not renewable (petroleum), so those resources will be more efficient in its use within a period much longer.