Improving bio-conditioning dewatering performance of food waste anaerobic digestate at low ambient temperatures by heating treatment.

Food waste anaerobic digestate (FWAD) containing high concentrations of contaminants must be purified or recycled. Bio-conditioning dewatering followed by activated sludge process (BDAS) has emerged as a promising technology for treating FWAD. However, the bio-conditioning dewatering as a pivotal step of BDAS is often negatively affected by low ambient temperatures often occurred in winter.

Effects of food waste hydrolysate as an external carbon source on defoaming in wastewater treatment with activated sludge process.

The activated sludge process is the most widely used technology for treating municipal wastewater. However, thick foam often occurs in activated sludge process. Here, we reported for the first time the effect of food waste hydrolysate (FWH) as an external carbon source on defoaming in activated sludge process.

Insight into performance of nitrogen removal enhanced by adding lactic acid-rich food waste fermentation liquid as carbon source in municipal wastewater treatment.

Lactic acid-rich fermentation liquid (LAFL) of food waste is found to act as a promising alternative carbon source for nitrogen removal in wastewater treatment. Here, LAFL was employed to investigate its impacts on nitrogen removal during raw municipal wastewater treatment with a comparison to sodium acetate (NaAc). Results indicated that nitrogen removals were comparable when incorporated with LAFL and NaAc (92.

A novel approach for purifying food waste anaerobic digestate through bio-conditioning dewatering followed by activated sludge process: A case study.

Although anaerobic digestion is the mainstream technology for treating food waste (FW), the high pollutant concentration in the resultant food waste anaerobic digestate (FWAD) often poses challenges for the subsequent biochemical treatment such as activated sludge process. In this study, taking a typical FW treatment plant as an example, we analyzed the reasons behind the difficulties in treating FWAD and tested a novel process called as bio-conditioning dewatering followed by activated sludge process (BDAS) to purify FWAD. Results showed that high concentrations of suspended solids (SS) (16439 ± 475 mg/L), chemical oxygen demand (COD) (24642 ± 1301 mg/L), and ammonium nitrogen (NH-N) (2641 ± 52 mg/L) were main factors affecting the purification efficiency of FWAD by the conventional activated sludge process.

Aeration pre-treatment role in improving the performance of bio-conditioning dewatering of food waste anaerobic digestate.

Bio-conditioning dewatering followed by activated sludge process (BDAS) is a promising technology for purifying food waste anaerobic digestate (FWAD). However, the bio-conditioning dewatering efficiency is often affected by FWAD properties and ambient temperature. Here, we firstly reported that aeration pre-treatment of FWAD played an important role in improving the bio-conditioning dewatering performance of FWAD.

Enhanced dewatering extent of sludge by FeO-driven heterogeneous Fenton.

Homogeneous Fenton (Fe/HO) serves as a high-efficiency conditioning method for sludge dewatering due to the generation of strong oxidizing hydroxyl radicals (OH). However, high dose of ferric salts produces iron-rich dewatered sludge and decrease sludge organic matters, which will not be conducive to the subsequent disposal and reutilization. Considering advantages of FeO as heterogeneous Fenton catalyst, FeO-activated HO (FeO + HO) in this study was adopted to improve sludge deep-dewatering.

Promoting dewatering efficiency of sludge by bioleaching coupling chemical flocculation.

In recent years, bioleaching has emerged as a cost-effective technology for enhancing the dewaterability of sludge. However, the lengthy treatment time involved in sludge bioleaching processes limits daily treatment capacity for sludge. Here, a novel approach was developed through a short time of sludge bioleaching with A.

Schwertmannite-based heterogeneous Fenton for enhancing sludge dewaterability over a wide pH range.

Fe-based Fenton technology is commonly used to enhance sludge dewaterability, but it requires subsequent neutralization, resulting in excessive chemical consumption. In this study, we investigated the feasibility of using schwertmannite-composited FeO (Sch/FeO) as a heterogeneous Fenton catalyst to enhance sludge dewaterability without the need for pH adjustment. A high reduction efficiency of sludge specific resistance to filtration (94.

Feasibility of Bio-Coagulation Dewatering Followed by Bio-Oxidation Process for Treating Swine Wastewater.

The unsatisfactory performance of the conventional swine wastewater treatment is drawing increasing attention due to the large amount of refractory chemical oxygen demand (COD), nitrogen, and phosphorus attached to the suspended solids (SS). In this study, for the first time, a novel process based on bio-coagulation dewatering followed by a bio-oxidation (BDBO) system was developed to treat swine wastewater containing high-strength SS, COD, TN, and TP. Firstly, after the bio-coagulation process, the removal efficiencies of SS, COD, NH-N, and TP reached as high as 99.

Enhancing propionic acid production in the acidogenic fermentation of food waste facilitated by a fungal mash under neutral pH.

Fungal mash derived from Aspergillus spp. is a green enzymatic additive for food waste (FW) valorization. In this study, the production of volatile fatty acids (VFAs) and the proportion of propionic acid (PA) in VFAs were increased by utilizing a complex enzyme (CE) obtained from Aspergillus oryzae.

Elucidating interactive effects of sulfidated nanoscale zero-valent iron and ammonia on anaerobic digestion of food waste.

In our previous study, anaerobic digestion of food waste could be effectively enhanced by adding sulfidated nanoscale zero-valent iron (S-nZVI) under high-strength ammonia concentrations. In this study, in order to further elucidate the specific interactive effects of S-nZVI and ammonia on anaerobic digestion of nitrogen-rich food waste, the methanogenic performance of anaerobic digestion systems respectively added with nanoscale zero-valent iron (nZVI) and S-nZVI were compared and monitored under different ammonia stress conditions. Both nZVI and S-nZVI could effectively stimulate the methanogenesis process among ammonia concentrations ranging from 0 to 3500 mg/L.

Fungal mash enzymatic pretreatment combined with pH adjusting approach facilitates volatile fatty acids yield via a short-term anaerobic fermentation of food waste.

As an alternative for commercial enzyme, crude enzyme of fungal mash could promote food waste (FW) hydrolysis, but its specific effects coupled pH adjusting on the production of volatile fatty acids (VFAs) remains unknown. The crude enzyme produced from an Aspergillus awamori, named complex-amylase (CA), was added to short-term anaerobic system of FW fermentation. Results showed that adding CA significantly improved the solubility and degradability of biodegradable and non-biodegradable organics in FW, where the SCOD concentration with adding CA increased by 116.

Efficient adsorption of Cr(VI) in acidic environment by nano-scaled schwertmannite prepared through pH regulation: characteristics, performances, and mechanism.

Acidic Cr(VI)-containing wastewater has received increasing attention in recent years. Schwertmannite is a suitable adsorbent for its acid resistance and good adsorption ability. However, it shows poor Cr(VI) adsorption performance under acidic conditions.

Isolation and characterisation of Fe(II)-oxidising bacteria and their application in the removal of arsenic in an aqueous solution.

Arsenic (As) is a toxic metalloid disseminated in water, soil, and air. Arsenic contamination is currently a major public health concern. This study investigated arsenic removal by Fe(II)-oxidising bacteria in an aqueous solution.

Food waste hydrolysate as a carbon source to improve nitrogen removal performance of high ammonium and high salt wastewater in a sequencing batch reactor.

The high ammonium and high salt (HAHS) wastewater generated from the anaerobic digestate of food waste is usually difficult to be treated by biological process because of its low C/N ratio. Herein, food waste hydrolysate (FWH) is rich in readily biodegradable organic matter, was utilized as carbon source to enhance the nitrogen removal of HAHS in the activated-sludge system. Results showed that compared with the control average total nitrogen removal efficiency increased from 73.

Nitrogen removal performance of high ammonium and high salt wastewater by adding carbon source from food waste fermentation with different acidogenic metabolic pathways.

Food waste fermentation liquid components, mainly lactate and volatile fatty acids (VFAs), can be used as alternative carbon sources to improve the nitrogen removal efficiency. To investigate the effects of carbon sources generated from food waste (FW) fermentation liquid on nitrogen removal for the treatment of high ammonium and high salt wastewater (HAHS), the lactate, acetate, propionate, butyrate, and their mixtures were added in activated sludge systems operating over 130-days. Lactate and butyrate inhibited nitrifiers by enriching polyphosphate accumulating organisms (PAOs), thus deteriorated nitrogen removal after a long-term period.

Hydroxyl, Fe, and Jointly Determined the Crystal Growth and Morphology of Schwertmannite in a Sulfate-Rich Acidic Environment.

Schwertmannite, ubiquitously found in iron and sulfate-rich acid mine drainage, is generated via biological oxidation of ferrous ions by . However, little information on the mechanisms of biogenic schwertmannite formation and crystal growth is available. This study deliberately investigated the relationships among mineral morphology, solution chemistry, and phase transformation of schwertmannite in -containing ferrous sulfate solutions.

Fabricating FeO-schwertmannite as a Z-scheme photocatalyst with excellent photocatalysis-Fenton reaction and recyclability.

Here we reported an effective method to solve the rate-limiting steps, such as the reduction of Fe to Fe and an invalid decomposition of HO in a conventional Fenton-like reaction. A magnetic heterogeneous photocatalyst, FeO-schwertmannite (FeO-sch) was successfully developed by adding FeO in the formation process of schwertmannite. FeO-sch shows excellent electrons transfer ability and high utilization efficiency of HO (98.

Improving solid-liquid separation performance of anaerobic digestate from food waste by thermally activated persulfate oxidation.

Anaerobic digestion is a promising ecofriendly technology for the management of the continuous increasing food waste (FW). However, the large amount of resulting anaerobic digestate are very difficult to be purified due to high concentration of suspended colloids. Solid-liquid separation is a pivotal step for the subsequent biological treatment of the digestate by activated sludge process.

Recovering iron and sulfate in the form of mineral from acid mine drainage by a bacteria-driven cyclic biomineralization system.

Acid mine drainage (AMD) is recognized as a challenge encountered by mining industries globally. Cyclic mineralization method, namely Fe oxidation/mineralization-residual Fe reduction-resultant Fe oxidation/mineralization, could precipitate Fe and SO present in AMD into iron hydroxysulfate minerals and greatly improve the efficiency of subsequent lime neutralization, but the current Fe-mediated reduction approach increased the mineralization cycles. This study constructed a bacteria-driven biomineralization system based on the reactions of Acidithiobacillus ferrooxidans-mediated Fe oxidation and Acidiphilium multivorum-controlled Fe reduction, and utilized water-dropping aeration and biofilm technology to satisfy the requirement of practical application.

A novel approach for treating acid mine drainage through forming schwertmannite driven by a mixed culture of Acidiphilium multivorum and Acidithiobacillus ferrooxidans prior to lime neutralization.

As the predominant treatment approach of acid mine drainage (AMD), lime neutralization often exhibits inefficiencies since the abundance of iron and sulfate in AMD usually form iron hydroxide and gypsum precipitate coatings on the surface of lime. In this study, a novel approach of biomineralization prior to lime neutralization for treating AMD was proposed, in which iron and sulfate were biologically precipitated as schwertmannite through iron biological reduction-oxidation driven by a culture mixed with Acidiphilium multivorum JZ-6 and Acidithiobacillus ferrooxidans LX5. It was found that only five cycles of iron reduction by A.

The coupling reaction of Fe bio-oxidation and resulting Fe hydrolysis drastically improve the formation of iron hydroxysulfate minerals in AMD.

The oxidation of Fe by () in acid mine drainage (AMD) is often accompanied by formation of iron hydroxysulfate minerals, such as schwertmannite and jarosite. This study reported that 80 mmol L of Fe could be completely oxidized by LX5 within 48 h, but only 27.7% of the resultant Fe precipitated to form schwertmannite.

A novel approach coupling ferrous iron bio-oxidation and ferric iron chemo-reduction to promote biomineralization in simulated acidic mine drainage.

A novel -mediated approach coupling biological oxidation and chemical reduction for treating acid mine drainage (AMD) was investigated. The results showed that controlled addition of zero valent iron (ZVI) into the coupling system did not exhibit a significant adverse influence on the bacterial activity of but markedly increased the formation of secondary Fe-minerals. Nutrition did not affect the efficiency of coupling process, except for the bacteria density of .

A novel approach to rapidly purify acid mine drainage through chemically forming schwertmannite followed by lime neutralization.

Acid mine drainage (AMD) has been recognized as a major challenge to the global mining industry due to its environmental consequences. Lime neutralization has been a traditional treatment for AMD, but the abundance of iron and sulfate in AMD usually renders it ineffective by forming iron hydroxide and gypsum precipitate coating on the surface of lime. In light of ubiquitous biological mineralization phenomena present at AMD sites, a rapid chemical mineralization was developed to reduce iron and sulfate and recovery of iron from AMD prior to lime neutralization.

Bioleached sludge composting drastically reducing ammonia volatilization as well as decreasing bulking agent dosage and improving compost quality: A case study.

Sludge bioleaching technology with Acidithiobacillus species has been commercially adopted for improving advanced dewatering of sludge in China since 2010. However, up to now, little information on bioleached dewatered sludge (BS) composting is available. Here, we report the changes of physicochemical and biological properties in BS composting and evaluate compost product quality compared to conventional dewatered sludge (CS) composting in an engineering scale composting facility.