Operating costs for the treatment of coking wastewater

I have been involved in the treatment of coking wastewater from a coking plant: Ammonia evaporation involves costs related to steam, and the ammonia produced is then absorbed using concentrated sulfuric acid, which is used to produce sulfuric acid and nitrogen fertilizers for sale. The subsequent processes include air flotation, hydrolysis-acidification, secondary contact oxidation, followed by coagulation and sedimentation. Since the steam is used in an internal cycle within the plant, its cost is low; the total treatment cost is approximately 9–11 yuan per ton.

1. Biochemical operation costs: ① Electricity consumption – The current wastewater treatment capacity is 50 m3/h, resulting in a daily treatment volume of 1200 m3. The operating power is 300 kW, with an electricity cost of 0.5 yuan/kWh. The cost of electricity per ton of water used is: (300/50)×0.5=3 yuan. ② Water costs: The water used in biochemical industries includes water for fan cooling and water for defoaming purposes; the consumption is 25 m3/h, and the cost of water is 1 yuan/m3. The cost of clean water required to treat one ton of wastewater is: (25/50)×1=0.5 yuan. ③ The chemicals that need to be added for biochemical treatment include soda ash (sodium carbonate), phosphates (sodium metaphosphate), polyaluminum (polyaluminum chloride), polyiron (polyferric chloride), and PAM (polyacrylamide). The usage amounts and unit prices are as follows: Soda ash: 1500 kg/day, with a consumption of 1.25 kg per ton of water; the unit price is 2.83 yuan/kg. Thus, the cost of soda ash per ton of water is: 1.25 × 2.83 = 3.6 yuan. Phosphates: 150 kg/day, with a consumption of 0.125 kg per ton of water; the unit price is 4.2 yuan/kg. Therefore, the cost of phosphates per ton of water is: 0.125 × 4.2 = 0.525 yuan. Polyaluminum: 200 kg/day, with a consumption of 0.1667 kg per ton of water; the unit price is 1.88 yuan/kg. Hence, the cost of polyaluminum per ton of water is: 0.1667 × 1.88 = 0.3134 yuan. Polyiron: 25 kg/day, with a consumption of 0.0208 kg per ton of water; the unit price is 2.145 yuan/kg. Thus, the cost of polyiron per ton of water is: 0.0208 × 2.145 = 0.0446 yuan. PAM: 6 kg/day, with a consumption of 0.005 kg per ton of water; the unit price is 4 yuan/kg. Therefore, the cost of PAM per ton of water is: 0.005 × 4 = 0.2 yuan. In total, the cost of these chemicals per ton of water is 3.6 + 0.525 + 0.3134 + 0.0446 + 0.2 = 4.683 yuan. ④Testing reagents: The cost of chemicals for the biochemical laboratory is 5,000 yuan per month. Therefore, the amount of chemicals required per ton of water is: 5,000 / (30 × 1,200) = 0.138, which is approximately 0.14 yuan. ⑤ Depreciation costs: The depreciation cost for biochemical equipment is 98,000 yuan per month (this figure was provided by the finance department). Thus, the depreciation cost per ton of water is: 98,000 / (30 × 1,200) = 2.722 yuan. ⑥ Maintenance costs: These include major and minor repairs to the equipment as well as the replacement of valve components, and amount to 15,000 yuan per month. Hence, the maintenance cost per ton of water is: 15,000 / (1,200 × 30) = 0.416, or approximately 0.42 yuan. ⑦ Staff salaries: There are currently 34 employees working in the biochemical department. If the salary for employees is calculated at 1,500 yuan per month, then the cost associated with labor per ton of water processed is: 1,500×34/(1,200×30) = 1.4167, which rounds to 1.42 yuan. ⑧ Administrative costs: These are charged at 10% of the operating costs; thus, the amount is: (3 + 0.5 + 4.683 + 0.14 + 2.722 + 0.42 + 1.42) × 0.1 = 1.2885. ⑨ The total cost is: 3 + 0.5 + 4.683 + 0.14 + 2.722 + 0.42 + 1.42 + 1.2885 = 14.1735 yuan

3# A single boat – it uses quite little electricity, only 300 KW per day? It’s not quite appropriate; I’ll need 2500 KW for just one day. So what process are you talking about? There's time to go and take a look/learn something

The wastewater treatment company selected by my company seems to use a process similar to that used upstairs; the issue is that the process you chose results in a higher power consumption per hour. My company’s power consumption per hour is around 200. As for our operating costs, the first four types of expenses are approximately 4.0 yuan less compared to those of the company upstairs. However, due to differences in staffing and equipment configuration, I don’t think there’s any comparability or relevance here.

The cost of treating coking wastewater is too high. For a project our company is working on in the north, the client told us that once they passed the environmental regulations check, there would be no need for wastewater treatment anymore, as the costs associated with it are too high; after all, the cost of using tap water there is just over one yuan per unit. In a word, it’s not worth it.