TY - JOUR

T1 - Grey water treatment in stacked multi-layer reactors with passive aeration and particle trapping

AU - Prajapati, B.

AU - Jensen, M. B.

AU - Jørgensen, N. O.G.

AU - Petersen, N. B.

PY - 2019/9/15

Y1 - 2019/9/15

N2 - When adequately treated, grey water represents a potent alternative water resource, as it constitutes a large proportion of household wastewater. The objective of this paper was to test a full scale version of a novel compact grey water treatment technology, based on passive aeration and particle trapping in multiple layers. Using a modified dual porosity filtration technology, grey water from a public bath was passed through a stack of eight reactors, each 0.75 m × 0.55 × 0.22 m, serially connected for gravity driven flow from top to bottom in a zig-zag pattern. The topmost reactor served as pre-filter for removal of hair and other larger debris. The lower seven reactors facilitated degradation of bulk organic contaminants in biofilm established on a stack of five fibrous polyamide nets, and trapping of particles by sedimentation on five interlaid corrugated plastic plates. By operating the reactors in a time-controlled batch-mode, the corrugated plates further served to trap air and thus ensure passive aeration of the subsequent batch. The production rate was 1.2 m3/d and the hydraulic retention time 2 h, at an aerial footprint of 0.4 m2, excluding storage tanks. After two weeks of initialization, a biofilm had established and the system was monitored for additionally three weeks. Significantly improved effluent quality was obtained as measured from reductions in turbidity (95%), total suspended solids (94%), chemical oxygen demand (87%), and microbiological parameters (55–98%), and from stable level of dissolved oxygen in effluent of 3.5 mg/L. Future optimization includes custom-made reactors for maximizing production capacity, improved removal of total N and total P, and addition of final disinfection.

AB - When adequately treated, grey water represents a potent alternative water resource, as it constitutes a large proportion of household wastewater. The objective of this paper was to test a full scale version of a novel compact grey water treatment technology, based on passive aeration and particle trapping in multiple layers. Using a modified dual porosity filtration technology, grey water from a public bath was passed through a stack of eight reactors, each 0.75 m × 0.55 × 0.22 m, serially connected for gravity driven flow from top to bottom in a zig-zag pattern. The topmost reactor served as pre-filter for removal of hair and other larger debris. The lower seven reactors facilitated degradation of bulk organic contaminants in biofilm established on a stack of five fibrous polyamide nets, and trapping of particles by sedimentation on five interlaid corrugated plastic plates. By operating the reactors in a time-controlled batch-mode, the corrugated plates further served to trap air and thus ensure passive aeration of the subsequent batch. The production rate was 1.2 m3/d and the hydraulic retention time 2 h, at an aerial footprint of 0.4 m2, excluding storage tanks. After two weeks of initialization, a biofilm had established and the system was monitored for additionally three weeks. Significantly improved effluent quality was obtained as measured from reductions in turbidity (95%), total suspended solids (94%), chemical oxygen demand (87%), and microbiological parameters (55–98%), and from stable level of dissolved oxygen in effluent of 3.5 mg/L. Future optimization includes custom-made reactors for maximizing production capacity, improved removal of total N and total P, and addition of final disinfection.

KW - Decentralized

KW - Dual porosity filtration

KW - Grey water reuse

KW - Low-cost

KW - Multi-layer reactor

KW - Space-efficient

UR - http://www.scopus.com/inward/record.url?scp=85066963292&partnerID=8YFLogxK

U2 - 10.1016/j.watres.2019.05.096

DO - 10.1016/j.watres.2019.05.096

M3 - Journal article

C2 - 31195334

AN - SCOPUS:85066963292

VL - 161

SP - 181

EP - 190

JO - Water Research

JF - Water Research

SN - 0043-1354

ER -