Greenhouse gas reduction of co-benefit-type wastewater treatment system for fish-processing industry: A real-scale case study in Indonesia

This study examined the application of co-benefit-type wastewater treatment technology in the fish-processing industry. Given that there was a dearth of information on fish-processing industrial wastewater in Indonesia, site surveys were conducted. For the entire fish-processing industry throughout the country, the dissemination rate of wastewater treatment facilities was less than 50%. Using a co-benefit approach, a real-scale swim-bed technology (SBT) and a system combining an anaerobic baffled reactor (ABR) with SBT (ABR–SBT) were installed in a fishmeal processing factory in Bali, Indonesia, and the wastewater system process performance was evaluated. In a business-as-usual scenario, the estimated chemical oxygen demand load and greenhouse gas (GHG) emissions from wastewater from the Indonesian fish-processing industry were 33 000 tons per year and 220 000 tons of equivalent CO_(2) per year, respectively. On the other hand, the GHG emissions in the co-benefit scenarios of the SBT system and ABR–SBT system were 98 149 and 26 720 tons per year, respectively. Therefore, introducing co-benefit-type wastewater treatment to Indonesia’s fish-processing industry would significantly reduce pollution loads and GHG emissions.

Profit Analysis by Soil Carbon Sequestration with Different Composts and Cooperated with Biochar during Corn (Zea mays) Cultivation Periods in Sandy Loam Soil

Despite the ability of biochar to enhance soil fertility and to sequester soil carbon, its potential reduction of green house gas emissions and profit analysis with different organic composts and cooperated with biochar for crop cultivation have been a few evaluated. This study was conducted to estimate their greenhouse gas emission reduction and profit analysis by soil carbon sequestration with different organic composts and cooperated with biochar application during corn cultivation periods. For the experiment, the treatments were consisted of aerobic digestate of swine wastes (AD), pig compost as the control (PC), cow compost (CC) and pig compost cooperated with 1% biochar (PC + 1% biochar). The soil texture used in this study was sandy loam, and application rates of chemical fertilizer were 190-39-221 kg·ha-1 (N-P2O5-K2O) as recommended amount after soil test. The soil samples were periodically taken at every 15 day intervals during the experimental periods. It was observed that soil carbon sequestration by AD, CC and PC + 1% biochar application was estimated to be 429 kg·ha-1, 2366 kg·ha-1, and 3978 kg·ha-1, and their CO2-e emission reductions were estimated to be 0.16 tones for AD, 0.87 tones for CC, and 14.58 tones for PC + 1% biochar per hectar for corn cultivation periods. Their profits were estimated at $14.58 for lowest and $451.90 for highest. In Korea Climate Exchange, it was estimated to be $115.20 per hectar of corn cultivation with PC + 1% biochar. So, the price of CO2 per hectar for corn cultivation with PC + 1% biochar was high at 16.8 times relative to cow compost treatment only. For the plant growth response, it was observed that plant height and fresh ear yield were not significantly different among the treatments. Therefore, these experimental results might be fundamental data for assuming a carbon trading mechanism exists for biochar soil application in agricultural practices.

Effects of the nitrification inhibitor nitrapyrin and the plant growth regulator gibberellic acid on yield-scale nitrous oxide emission in maize fields under hot climatic conditions

Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N_(2)O)emission and increase crop yield.However,no concrete information on their mitigation of N_(2)O emission is available under soil and environmental conditions as in Pakistan.A field experiment was established using a silt clay loam soil from Peshawar,Pakistan,to study the effect of urea applied in combination with a nitrification inhibitor,nitrapyrin(2-chloro-6-tri-chloromethyl pyridine),and/or a plant growth regulator,gibberellic acid(GA_3),on N_(2)O emission and the nitrogen(N)uptake efficiency of maize.The experimental design was a randomized complete block with five treatments in four replicates:control with no N(CK),urea(200 kg N ha^(-1))alone,urea in combination with nitrapyrin(700 g ha^(-1)),urea in combination with GA_3(60 g ha^(-1)),and urea in combination with nitrapyrin and GA_3.The N_(2)O emission,yield,N response efficiency,and total N uptake were measured during the experimental period.The treatment with urea and nitrapyrin reduced total N_(2)O emission by 39%–43%and decreased yield-scaled N_(2)O emission by 47%–52%,relative to the treatment with urea alone.The maize plant biomass,grain yield,and total N uptake increased significantly by 23%,17%,and 15%,respectively,in the treatment with urea and nitrapyrin,relative to the treatment with urea alone,which was possibly due to N saving,lower N loss,and increased N uptake in the form of ammonium;they were further enhanced in the treatment with urea,nitrapyrin,and GA_3 by 27%,36%,and 25%,respectively,probably because of the stimulating effect of GA_3 on plant growth and development and the reduction in biotic and abiotic stresses.These results suggest that applying urea in combination with nitrapyrin and GA_3 has the potential to mitigate N_(2)O emission,improve N response efficiency,and increase maize yield.