Carbon capture for blackwater: chemical enhanced high-rate activated sludge process

Abstract

Blackwater has more benefits for carbon recovery than conventional domestic wastewater. Carbon capture and up-concentration are crucial prerequisites for carbon recovery from blackwater, the same as domestic wastewater. Both chemical enhanced primary treatment (CEPT) and high-rate activated sludge (HRAS) processes have enormous potential to capture organics. However, single CEPT is subject to the disruption of influent sulfide, and single HRAS has insufficient flocculation capacity. As a result, their carbon capture efficiencies are low. By combining CEPT and HRAS with chemical enhanced high rate activated sludge (CEHRAS) process, the limitations of single CEPT and single HRAS offset each other. The carbon mineralization efficiency was significantly influenced by SRT rather than iron salt dosage. An iron dosage significantly decreased chemical oxygen demand (COD) lost in effluent. Both SRT and iron dosage had a significant influence on the carbon capture efficiency. However, HRT had no great impact on the organic mass balance. CEHRAS allowed up to 78.2% of carbon capture efficiency under the best conditions. The results of techno-economic analysis show that decreasing the iron salt dosage to 10 mg Fe/L could promise profiting for blackwater treatment. In conclusion, CEHRAS is a more appropriate technology to capture carbon in blackwater.

Evolution and Prospects in Managing Sewage Sludge Resulting from Municipal Wastewater Purification

“…Step aeration [100][101][102] Modified aeration (with or without primary settling) [100][101][102] High-rate ASP [100][101][102]104] Extended aeration [105][106][107] Hatfield and Krauss processes [108][109][110] Contact stabilization [111][112][113][114] Membrane bioreactor (MBR) [115][116][117] Sequencing batch reactor (SBR) [118][119][120][121] The microorganisms partly feed on and partly retain various inorganic compounds; for example, modern activated sludge plants manage to retain about 90% of the phosphorus; even in the case of wastewater with a high phosphorus content (about 15-20 mg/L), the component value is below 2 mg/L, which is the maximum value allowed in many developed countries [122]. Furthermore, these microorganisms retain a good percentage of different heavy metals present in MWW [123].…”

The application of membrane sequencing batch reactors in high rate activated sludge processes: the effect of the organic loading rate on the bioflocculation and fouling phenomenon

“…If the electricity generation and heat recovery efficiency of the internal combustion engine are considered equal to 39.5% and 39.0%, respectively, 41 then the corresponding additional electricity and heat production will be 0.10 kWh Environmental Science: Water Research & Technology Paper per kg COD feed and 0.091 kWh per kg COD feed , respectively. If the electricity price in industrial systems is taken to be 0.11 USD per kWh, 39 the additional energy produced by this method can save up to 0.021$ per kg COD feed . Also, sludge bulking is a common problem in SBR processes 42 and can lead to high suspended solids in the effluent, therefore resulting in a significant reduction in COD and energy recovery.…”