Farm wastewater treatment is a big topic, with key technical points explained in detail

“We want both clear waters and green mountains, and also mountains of gold and silver. We would rather have clear waters and green mountains than mountains of gold and silver, and moreover, clear waters and green mountains are themselves mountains of gold and silver.”   ——Xi Jinping

The most troublesome problem for farms is the treatment of animal manure and wastewater. If they are discharged at will, they not only pollute rivers and the environment, but also cause overwhelming stench inside and outside the farm, wastewater flowing everywhere, swarms of mosquitoes and flies, and pathogens spreading everywhere. The animals' growing environment is severely polluted, animal health is threatened, animal safety is not guaranteed, and animal quality declines. It is precisely for this reason that many farms have low efficiency, or go bankrupt and close down, or are ordered by government departments to rectify or shut down.
 

So how can farm wastewater be effectively treated? How can we avoid polluting the environment while also effectively using waste and turning waste into treasure? To find the answer, the reporter came to Zhaobao Ecological Farm in Fujian Province, famous for ecological breeding of wild animals.

As soon as you step into the farm, you immediately feel refreshed and relaxed: because this place does not look like a farm at all, and you would never imagine that this could be a large-scale farm producing millions of rare birds and wild animals annually. Surrounded by green trees, with birdsong and fragrant flowers, it gives the impression of a holiday resort —— everywhere you look is greenery, everything you smell is osmanthus fragrance and fresh grass, and everything you hear is the warbling of birds. On this nationally renowned special wild animal farm, you cannot see a bit of wastewater or smell a bit of stench. How does Zhaobao Farm achieve this?

1. Ecological recycling technology

Ecological recycling is an agricultural production model strongly advocated by the state and also the direction of world agricultural development. Lan Zhaoyan, chairman of Zhaobao Farm, recognized the importance of ecological recycling to the farm's production development and environmental protection as early as before 1995. Therefore, he consulted a large amount of ecological technical material from around the world and, combined with his own practice, established a unique ecosystem of recycling between breeding and planting.

This system includes a scientific and reasonable water supply and drainage system, biological deodorization technology, biogas digester, wastewater treatment pond, plant plantation, and so on. The specific principle is that animal manure and wastewater produced by breeding enter the biogas digester to ferment into biogas energy. The biogas residue and biogas slurry from the digester are used to irrigate plants such as fruit trees, forage grass, corn, vegetables, flowers and nursery stock. The forage grass, corn, vegetables and so on are used to feed the animals. In this way, the cycle repeats endlessly and continuously.

2. Treatment and utilization of wastewater

Although most animal manure enters the biogas digester for utilization, the wastewater from washing animal pens still needs to be treated. The farm established five purification and sedimentation ponds. Biological agents are added to the wastewater for deodorization, and then it is sedimented pond by pond, finally entering a large pond full of water hyacinth. Water hyacinth has a well-developed root system and can purify wastewater, making it clear. Once the purified water accumulates to a certain amount, it naturally flows out through pipes and irrigates the forage grass and osmanthus trees around the reservoir. The water treated in this way basically meets the national Class 2 discharge standard. Water hyacinth can also be used to feed animals such as wild boars, so it can truly be said that everything is a treasure.