Strategy for nitrogen removal from piggery waste

Abstract

This study was conducted with an influent containing about 20% solids, obtainable from scraper type separation resulting in about 40 g/L TCOD and 5.5 g/L TKN, to find an optimum operating condition for nitrogen removal. Both laboratory scale reactors and a full scale treatment plant removed 80 to 90% nitrogen by biological means up to 35 degrees C with 10% by ammonia stripping. The full scale plant however was operated at 35 to 45 degrees C, and at 45 degrees C, 30% nitrogen was removed by biological means, 50% by ammonia stripping, 14% by chemical coagulation and 6% by activated carbon adsorption, respectively. Struvite formation could not be observed at 30 degrees C or higher. Nitrite nitrification and denitrification could save about 35% in tank volume and 50% in carbon requirements at 25 degrees C, respectively. For a complete denitrification with a proper temperature, the influent TCOD/TKN ratio must exceed 6 with oxic/total reactor volume ratio of 0.5. The influent TCOD level or organic load should be lower so as not to increase the reactor temperature above 35 degrees C and avoid nitrification inhibition. The estimated optimum nitrogen loading rates were 0.15 for summer and 0.23 kg TKN/m3/d for winter, respectively. With a cooling facility, the nitrogen loads could be increased to 0.35 kg TKN/m3/d equivalent to an organic loading rate of 2.5 kg COD/m3/d.

Application of membrane bioreactor system with full scale plant on livestock wastewater

“…In relation to above factors, the nitrification rate generally varied with availability of alkalinity, organic and nitrogen loads, temperature and others (Choi et al, 2003). The temperature of the bioreactor in the summer season was generally elevated to about 50 8C by the large amount of heat released from the microbial reaction in the organic load should be lower down so as not to increase the reactor temperature higher than 35 8C to avoid nitrification inhibition (Choi and Eum, 2001). Accordingly it needs heat control to get a sufficient nitrification rate without a cooling facility.…”

Khảo sát hiệu quả xử lý nước thải chăn nuôi heo sau bể biogas bằng công nghệ lọc sinh học kết hợp bãi lọc thực vật

“…Mỗi năm khối lượng nguồn thải từ chăn nuôi ra môi trường là khoảng 84,5 triệu tấn/năm, trong đó, chỉ khoảng 20% được sử dụng hiệu quả (làm khí sinh học, ủ phân, nuôi trùn, cho cá ăn,…), còn lại 80% lượng chất thải chăn nuôi đã bị lãng phí và phần lớn thải ra môi trường gây ô nhiễm (T. H. Nguyen, 2017). Nước thải chăn nuôi heo là nguồn nước thải có hàm lượng chất ô nhiễm cao (chất hữu cơ, chất dinh dưỡng, chất rắn lơ lửng), sẽ gây ô nhiễm môi trường nếu không xử lý tốt (Choi & Eum, 2002;Le, Le, & Nguyen, 2012).…”