Wastewater treatment system

Abstract

A treatment system and process is described herein to separate constituent parts from aqueous-based products or by-products, such as wastewater from a cellulosic ethanol process. The treatment system may include an ultrafiltration system, a first reverse osmosis system and a second reverse osmosis system. The treatment system may be configured to operate in modified batch mode.

1 . A wastewater treatment process, comprising:
 sending a volume of initial wastewater from a first receptacle through an ultrafiltration (UF) system to yield a UF permeate, wherein a UF concentrate filtered by the UF system is returned to the first receptacle;   feeding the UF permeate into a second receptacle;   passing a volume of second receptacle wastewater through a first reverse osmosis (RO) system to yield a first RO permeate, wherein a first RO concentrate filtered by the first RO system is returned to the second receptacle; and   moving the first RO permeate through a second RO system to yield a second RO permeate, wherein a second RO concentrate filtered by the second RO system is returned to the second receptacle.   
     
     
         2 . The wastewater treatment process according to  claim 1 , further comprising removing a receptacle concentrate from at least one of the first and second receptacles. 
     
     
         3 . The wastewater treatment process according to  claim 2 , further comprising recycling the receptacle concentrate for use as a fuel or fertilizer. 
     
     
         4 . The wastewater treatment process according to  claim 1 , wherein the wastewater is the by-product of a cellulosic ethanol process, constituents of the by-product selected from the group consisting essentially of whole stillage, thin stillage, process wash water, process chemical cleaning solution water, boiler blow down, cooling tower blow down, rain water run off, and combinations thereof. 
     
     
         5 . The wastewater treatment process according to  claim 4 , further comprising producing thin stillage by treating whole stillage using a centrifugation process. 
     
     
         6 . The wastewater treatment process according to  claim 4 , wherein the second RO permeate is substantially free of furfural, organic acids, total dissolved organic and inorganic solids (TDS), and total suspended solids (TSS). 
     
     
         7 . The wastewater treatment process according to  claim 1 , wherein the analytical composition of the wastewater includes a high concentration of total dissolved organic and inorganic solids (TDS), total organic carbon (TOC), total suspended solids (TSS), carbonaceous biochemical oxygen demand (CBOD), or metals, and combinations thereof. 
     
     
         8 . The wastewater treatment process according to  claim 1 , wherein the UF system includes one or more membranes having 1 inch tubes. 
     
     
         9 . The wastewater treatment process according to  claim 1 , wherein the second RO permeate includes a percentage of water from the initial wastewater in the range of about 90% to about 98%. 
     
     
         10 . The wastewater treatment process according to  claim 9 , wherein the second RO permeate is of sufficient quality to either be recycled and/or to meet the Louisiana Department of Environmental Quality (LDEQ) standard. 
     
     
         11 - 16 . (canceled) 
     
     
         17 . A treatment system to remove solids from wastewater, comprising:
 an ultrafiltration (UF) system;   a first reverse osmosis (RO) system; and   a second RO system, wherein a concentrate generated from each of the UF system, the first RO system, and the second RO system are recycled through the system.   
     
     
         18 . The treatment system according to  claim 17 , further comprising a first receptacle upstream of the UF system and a second receptacle between the UF system and the first RO system. 
     
     
         19 . The treatment system according to  claim 17 , further comprising a plurality of pumps configured to transfer wastewater and treated wastewater through the system. 
     
     
         20 . A method of treating wastewater from a cellulosic ethanol process, comprising:
 pumping a volume of wastewater, including thin stillage, through an ultrafiltration (UF) system to yield a UF permeate;   collecting the UF permeate in a receptacle;   pumping a volume of receptacle wastewater through a first reverse osmosis (RO) system to yield a first RO permeate; and   pumping the first RO permeate through a second RO system to yield a second RO permeate, wherein concentrates from the UF system, first RO system and second RO system are recycled upstream.   
     
     
         21 . The method of  claim 1 , wherein the ultrafiltration system is capable of retaining 99% of the suspended solids. 
     
     
         22 . The method of  claim 4 , wherein the thin stillage wastewater containing 0.5-3% total suspended solids and 1-3% of dissolved organic compounds 
     
     
         23 . The method of  claim 1 , wherein the total organic carbon is less than 50 mg/L. 
     
     
         24 . The method of  claim 23 , wherein the total organic carbon is less than 25 mg/L. 
     
     
         25 . The method of  claim 24 , wherein the total organic carbon is less than 10 mg/L.