1. Strictly anaerobic environment, biogas fermentation microorganisms include acidogenic bacteria and methanogens. They are anaerobic bacteria, especially methane producing bacteria, which are particularly sensitive to oxygen. They cannot survive in an aerobic environment. Even a small amount of oxygen will hinder the fermentation. Therefore, the construction of an airtight and watertight biogas digester is the key to the manual production of biogas.

2．足夠和優良的接種物接種物是沼氣發酵所需要的含有大量微生物的厭氧活性污泥，也稱菌種。只有具備足夠優良的接種物才能保證沼氣發酵高能運行。農村戶用沼氣池的接種物一般來源于老沼氣池的沼渣（沼液）、陰溝的污泥、糞坑底部的沉渣等。接種物用量一般占總發酵液的30％左右。

2. Sufficient and excellent inoculum inoculum is anaerobic activated sludge containing a large number of microorganisms required for biogas fermentation, also known as bacteria. Only with enough excellent inoculum can we ensure the high-energy operation of biogas fermentation. The inoculum of rural household biogas digester generally comes from the biogas residue (biogas slurry) of the old biogas digester, the sludge of the sewer, the sediment at the bottom of the cesspit, etc. The amount of inoculum generally accounts for about 30% of the total fermentation broth.

3．必要的發酵溫度沼氣發酵菌種在8℃～60℃范圍內都能發酵產氣，并且溫度越高，發酵越活躍，產沼氣越多。因此，作為常溫發酵的農村戶用沼氣池，應盡量使其發酵溫度保持在8℃以上。

3. Necessary fermentation temperature biogas fermentation strains can produce gas in the range of 8 ℃ ~ 60 ℃, and the higher the temperature, the more active the fermentation and the more biogas. Therefore, as a rural household biogas digester fermented at room temperature, the fermentation temperature should be kept above 8 ℃ as far as possible.

4．適宜的酸堿度在沼氣發酵過程中，沼氣菌適宜在中性或微堿性的環境中繁殖。發酵液的ph值控制在6.8～7.5為宜。如低于或高于此值，沼氣發酵就會緩慢，甚至不能正常進行。

4. Suitable pH during biogas fermentation, biogas bacteria are suitable to reproduce in neutral or slightly alkaline environment. The pH value of fermentation broth should be controlled at 6.8 ~ 7.5. If it is lower or higher than this value, biogas fermentation will be slow and even can not be carried out normally.

5．適宜的發酵濃度和碳氫比作物秸稈、青草、人畜糞便、生活污水等有機物都可以作為沼氣發酵的原料。但發酵原料需滿足(20～30)：1的碳氮比和滿足6%～10%的發酵濃度。當然，碳氮比和發酵濃度在夏季可適當低些，在冬季可適當高些。

5. Suitable fermentation concentration and hydrocarbon ratio, crop straw, grass, human and animal manure, domestic sewage and other organic matter can be used as raw materials for biogas fermentation. However, the fermentation raw materials should meet the carbon nitrogen ratio of (20 ~ 30): 1 and the fermentation concentration of 6% ~ 10%. Of course, the carbon nitrogen ratio and fermentation concentration can be appropriately lower in summer and higher in winter.

6．經常性的攪拌沼氣池。在不攪拌的情況下，發酵料液明顯地分為3層：上層結殼層、中層清液層、下層沉渣層。發酵液分層不利于產氣，所以，應考慮采取攪拌措施。攪拌的目的是使其不分層，讓原料和接種物均勻分布于池內，增加微生物與原料的接觸面，加快發酵速度，提高產氣量。此外，攪拌也有利于沼氣的釋放。對有加熱裝置的沼氣池來講，攪拌有利于熱能的傳播。目前，采用的攪拌方法主要有3種：機械攪拌、液攪拌、氣攪拌。

6. Regularly stir the biogas digester. Without stirring, the fermentation broth was obviously divided into three layers: upper crust layer, middle clear layer and lower sediment layer. Stratification of fermentation broth is not conducive to gas production, so stirring measures should be considered. The purpose of stirring is to make it non layered, evenly distribute raw materials and inoculum in the tank, increase the contact surface between microorganisms and raw materials, accelerate the fermentation speed and improve gas production. In addition, stirring is also conducive to the release of biogas. For biogas digesters with heating devices, stirring is conducive to the transmission of heat energy. At present, there are three main mixing methods: mechanical mixing, liquid mixing and gas mixing.

7．嚴防加入抑 制 劑。抑 制 劑主要是一些重金屬離子、農藥及一些有毒性物質。這類物質不能加入沼氣池。

7. Strictly prevent the addition of inhibitors. Inhibitors are mainly some heavy metal ions, pesticides and some toxic substances. Such substances cannot be added to the biogas digester.